阅读说明：本技术 用于在无线lan系统中配置针对宽频带发送的ngv帧的方法和装置 (Method and apparatus for configuring NGV frame for broadband transmission in wireless LAN system ) 是由 林东局 朴恩成 张仁善 崔镇洙 于 2019-10-01 设计创作，主要内容包括：提出了一种在无线LAN系统中发送NGV帧的方法和装置。具体地,发送装置生成NGV帧,并通过第一频带发送NGV帧。NGV帧包括L-STF、L-LTF、L-SIG、NGV-SIG、NGV-STF、NGV-LTF和NGV数据。L-STF、L-LTF、L-SIG和NGV-SIG以第二频带为单位被复制并且通过第一频带被发送。NGV-STF、NGV-LTF和NGV数据通过第一频带的全频带被发送。第一频带为20MHz频带,并且第二频带为10MHz频带。(A method and apparatus for transmitting an NGV frame in a wireless LAN system are provided. Specifically, the transmitting device generates an NGV frame, and transmits the NGV frame through the first band. The NGV frame includes L-STF, L-LTF, L-SIG, NGV-STF, NGV-LTF, and NGV data. The L-STF, L-LTF, L-SIG, and NGV-SIG are copied in units of a second band and transmitted through the first band. The NGV-STF, NGV-LTF and NGV data are transmitted over the full band of the first frequency band. The first frequency band is a 20MHz frequency band and the second frequency band is a 10MHz frequency band.)

1.A method for transmitting a new generation vehicular NGV frame in a wireless local area network system, the method comprising the steps of:

generating, by a transmitting device, an NGV frame; and

transmitting, by the transmitting device, the NGV frame to a receiving device over a first frequency band,

wherein the NGV frame includes a legacy short training field L-STF, a legacy long training field L-LTF, a legacy signal L-SIG, an NGV-STF, an NGV-LTF, and NGV data,

wherein the L-STF, the L-LTF, the L-SIG, and the NGV-SIG are duplicated in units of a second frequency band and transmitted through the first frequency band,

wherein the NGV-STF, the NGV-LTF, and the NGV data are transmitted over a full band of the first frequency band,

wherein the first frequency band is a 20MHz frequency band, and

wherein the second frequency band is a 10MHz frequency band.

2. The method of claim 1, wherein the NGV frame further comprises a duplicate legacy RL-SIG,

wherein the RL-SIG is duplicated in units of the second frequency band and transmitted through the first frequency band,

wherein the NGV frame includes a legacy portion, the NGV-SIG, and an NGV portion,

wherein the legacy portion comprises the L-STF, the L-LTF, the L-SIG, and the RL-SIG,

wherein the NGV portion includes the NGV-STF, the NGV-LTF, and the NGV data,

wherein the legacy portion and the NGV-SIG are generated by performing 2x down-converting DC to a frame format for a 20MHz band defined in an 802.11a system, and

wherein the NGV portion is generated by performing 2x down-conversion DC on a frame format for a 40MHz band defined in an 802.11ac system.

3. The method of claim 2, wherein the NGV portion has a set of orthogonal frequency division multiplexing, OFDM, parameters having a same symbol length as the legacy portion or a set of OFDM parameters having a symbol length 2 times the legacy portion.

4. The method of claim 2, wherein the AGC estimation information for the NGV portion is obtained from automatic gain control, AGC, estimation information obtained based on the L-STF, and

wherein the channel estimation information of the NGV portion is obtained from channel estimation information obtained based on the L-LTF.

5. The method of claim 2, wherein the RL-SIG is used to extend signal range and to perform packet classification, and

wherein the packet classification information is information classifying a legacy frame and the NGV frame.

6. The method of claim 2, wherein the RL-SIG or the NGV-SIG is modulated based on quadrature binary phase shift keying (Q-BPSK).

7. The method of claim 2, wherein additional tones are added to the L-SIG and the RL-SIG,

wherein the extra tones are used to perform channel estimation for the legacy portion and the NGV portion, and,

wherein a tone index of the additional tone is-28, -27, 28.

8. A transmission apparatus for transmitting a new-generation vehicular NGV frame in a wireless local area network system, the transmission apparatus comprising:

a memory;

a transceiver; and

a processor operatively connected to the memory and the transceiver,

wherein the processor is configured to:

generating the NGV frame, and

transmitting the NGV frame to a receiving device through a first frequency band,

wherein the NGV frame includes a legacy short training field L-STF, a legacy long training field L-LTF, a legacy signal L-SIG, an NGV-STF, an NGV-LTF, and NGV data,

wherein the L-STF, the L-LTF, the L-SIG, and the NGV-SIG are duplicated in units of a second frequency band and transmitted through the first frequency band,

wherein the NGV-STF, the NGV-LTF, and the NGV data are transmitted over a full band of the first frequency band,

wherein the first frequency band is a 20MHz frequency band, and

wherein the second frequency band is a 10MHz frequency band.

9. The transmission apparatus of claim 8, wherein the NGV frame further comprises a duplicate legacy RL-SIG,

wherein the RL-SIG is duplicated in units of the second frequency band and transmitted through the first frequency band,

wherein the NGV frame includes a legacy portion, the NGV-SIG, and an NGV portion,

wherein the legacy portion comprises the L-STF, the L-LTF, the L-SIG, and the RL-SIG,

wherein the NGV portion includes the NGV-STF, the NGV-LTF, and the NGV data,

wherein the legacy portion and the NGV-SIG are generated by performing 2x down-converting DC to a frame format for a 20MHz band defined in an 802.11a system, and

wherein the NGV portion is generated by performing 2x down-conversion DC on a frame format for a 40MHz band defined in an 802.11ac system.

10. The transmitting apparatus of claim 9, wherein the NGV portion has an orthogonal frequency division multiplexing, OFDM, parameter set having a same symbol length as the legacy portion or an OFDM parameter set having a symbol length 2 times the legacy portion.

11. The transmission apparatus according to claim 9, wherein AGC estimation information of the NGV portion is obtained from automatic gain control AGC estimation information obtained based on the L-STF, and

wherein the channel estimation information of the NGV portion is obtained from channel estimation information obtained based on the L-LTF.

12. The transmission apparatus of claim 9, wherein the RL-SIG is to extend a signal range and to perform packet classification, and

wherein the packet classification information is information classifying a legacy frame and the NGV frame.

13. The transmission apparatus of claim 9, wherein the RL-SIG or the NGV-SIG is modulated based on quadrature binary phase shift keying (Q-BPSK).

14. The transmission apparatus of claim 9, wherein additional tones are added to the L-SIG and the RL-SIG,

wherein the extra tones are used to perform channel estimation for the legacy portion and the NGV portion, and,

wherein a tone index of the additional tone is-28, -27, 28.

15. A method for receiving a new generation vehicular NGV frame in a wireless local area network system, the method comprising the steps of:

receiving, by a receiving device, the NGV frame from a transmitting device over a first frequency band; and

decoding the NGV frame by the receiving device,

wherein the NGV frame includes a legacy short training field L-STF, a legacy long training field L-LTF, a legacy signal L-SIG, an NGV-STF, an NGV-LTF, and NGV data,

wherein the L-STF, the L-LTF, the L-SIG, and the NGV-SIG are duplicated in units of a second frequency band and transmitted through the first frequency band,

wherein the NGV-STF, the NGV-LTF, and the NGV data are transmitted over a full band of the first frequency band,

wherein the first frequency band is a 20MHz frequency band, and

wherein the second frequency band is a 10MHz frequency band.

Technical Field

The present specification relates to a scheme for configuring an NGV frame in a wireless LAN system, and more particularly, to a method and apparatus for configuring an NGV frame in a wide frequency band to allow 802.11p and NGV interoperability (interoperable) in a wireless LAN system.

Background

Discussion is underway with respect to the next generation of Wireless Local Area Networks (WLANs). In the next-generation WLAN, the purpose is 1) to improve an Institute of Electrical and Electronics Engineers (IEEE)802.11 Physical (PHY) layer and a Medium Access Control (MAC) layer in 2.4GHz and 5GHz bands, 2) to improve spectrum efficiency and area throughput, 3) to improve performance in actual indoor and outdoor environments (e.g., an environment where an interference source exists, a dense heterogeneous network environment, and an environment where a high user load exists), and the like.

An environment mainly considered in the next generation WLAN is a dense environment in which Access Points (APs) and Stations (STAs) are many, and improvements in spectral efficiency and area throughput under the dense environment are discussed. Further, in the next generation WLAN, in addition to the indoor environment, substantial performance improvement in the outdoor environment, which is not sufficiently considered in the existing WLAN, is also concerned.

In particular, scenes of wireless offices, smart homes, stadiums, hotspots, and buildings/apartments are mainly focused in the next-generation WLAN, and improvement of system performance in a dense environment where there are many APs and STAs is discussed based on the corresponding scenes.

In the next generation WLAN, it is expected that the improvement of system performance in an Overlapping Basic Service Set (OBSS) environment and the improvement of outdoor environment performance and cellular offloading will be actively discussed, instead of the improvement of single link performance in one Basic Service Set (BSS). The directivity of the next generation means that the next generation WLAN gradually has a technical range similar to that of mobile communication. When considering the situation that mobile communication and WLAN technologies have been discussed in the field of small cell and direct-to-direct (D2D) communication in recent years, the technology and traffic convergence of next generation WLANs and mobile communication is expected to be more active.

Disclosure of Invention

Technical purpose

The present specification proposes a method and apparatus configured to transmit NGV frames in a wide band (wide band) in a wireless LAN system.

Technical scheme

One example of the present specification proposes a method for transmitting NGV frames.

The present embodiment can be performed in a network environment supported by the next generation wireless LAN system. The next generation wireless LAN system is an enhanced version of the 802.11p system that can satisfy backward compatibility with the 802.11p system. The next-generation wireless LAN system may also be referred to as a next-generation V2X (NGV) wireless LAN system or an 802.11bd wireless LAN system.

The embodiment is performed by a transmitting apparatus, and the transmitting apparatus may correspond to an AP. The receiving apparatus of this embodiment may correspond to an NGV STA supporting an NGV or 802.11bd system, or may correspond to an 11p STA supporting an 802.11p system.

This embodiment proposes a method for configuring an NGV frame for transmitting an NGV signal over a wide frequency band (20MHz or more) while satisfying interoperability, backward compatibility, or coexistence between an NGV or 802.11bd wireless LAN system and an 802.11p system that is a legacy system.

The transmitting device generates a New Generation Vehicle (NGV) frame.

The transmitting device transmits the NGV frame through the first frequency band.

The NGV frame includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG), a Repeated Legacy (RL) -SIG, an NGV-STF, an NGV-LTF, and NGV data.

The L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG are copied in units of a second frequency band and transmitted through the first frequency band. The first frequency band is a 20MHz frequency band and the second frequency band is a 10MHz frequency band. That is, the L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG may be configured in units of a 10MHz band (or channel), and, in order to transmit in a 20MHz band, frames (legacy portion and NGV-SIG) transmitted in the 10MHz band may be copied once and then transmitted.

In contrast, NGV-STF, NGV-LTF and NGV data are transmitted over the full band of the first band. That is, NGV-STF, NGV-LTF, and NGV data, which are the remaining fields except for the previously copied field, can be transmitted by using all of the entire 20MHz band (first band).

Advantageous effects

According to the embodiments proposed in the present specification, by configuring NGV frames interoperable between 802.11p and NGV, and by eliminating interference between 802.11p and NGV and transmitting NGV frames in a 20MHz band, improved throughput and fast communication speed can be achieved.

Drawings

Fig. 1 is a conceptual diagram illustrating the structure of a Wireless Local Area Network (WLAN).

Fig. 2 is a diagram showing an example of a PPDU used in the IEEE standard.

Fig. 3 is a diagram showing an example of the HE PDDU.

Fig. 4 is a diagram showing a layout of Resource Units (RUs) used in a frequency band of 20 MHz.

Fig. 5 is a diagram showing a layout of Resource Units (RUs) used in a frequency band of 40 MHz.

Fig. 6 is a diagram showing a layout of Resource Units (RUs) used in a frequency band of 80 MHz.

Fig. 7 is a diagram illustrating another example of the HE PPDU.

Fig. 8 is a block diagram illustrating one example of an HE-SIG-B according to an embodiment.

Fig. 9 shows an example of a trigger frame.

Fig. 10 shows an example of the common information field.

Fig. 11 shows an example of subfields included in the per-user information field.

Fig. 12 shows an example of a HE TB PPDU.

Fig. 13 shows a MAC frame format used in the wireless LAN system.

Fig. 14 shows an a-MPDU format used in the wireless LAN system.

Figure 15 shows a band plan for a 5.9GHz DSRC.

Fig. 16 shows a frame format of an 802.11p system.

Fig. 17 shows an example of an NGV PPDU format.

Fig. 18 shows another example of an NGV PPDU format.

Fig. 19 shows yet another example of an NGV PPDU format.

Fig. 20 shows an example of an NGV PPDU format transmitted in a 20MHz band.

Fig. 21 shows another example of an NGV PPDU format transmitted in a 20MHz band.

Fig. 22 shows an example of an NGV PPDU format transmitted in a 20MHz band and not including NGV-STF.

Fig. 23 shows an example of an NGV PPDU format transmitted in a 20MHz band and not including NGV-LTFs.

Fig. 24 shows an example of an NGV PPDU format transmitted in a 20MHz band and excluding NGV-STF and NGV-LTF.

Fig. 25 shows another example of an NGV PPDU format transmitted in a 20MHz band and not including NGV-STF and NGV-LTF.

Fig. 26 shows an example of an NGV PPDU format transmitted in a 20MHz band and composed of only an L section and NGV data.

Fig. 27 shows an example of tone plans for the NGV PPDU format of fig. 26.

Fig. 28 shows another example of a tone plan for the NGV PPDU format of fig. 26.

Fig. 29 shows a PPDU format in which RL-SIG is added to the NGV PPDU format of fig. 26.

Fig. 30 shows an example of an NGV PPDU format with a copied L part and NGV part.

Fig. 31 shows an example of a PPDU format that does not include NGV-STF in the NGV PPDU format of fig. 30.

Fig. 32 shows an example of a PPDU format that does not include NGV-LTF in the NGV PPDU format of fig. 30.

Fig. 33 shows an example of a PPDU format not including NGV-STF and NGV-LTF in the NGV PPDU format of fig. 30.

FIG. 34 shows an example of a PPDU format that does not include NGV-STF, NGV-LTF, and NGV-SIG in the NGV PPDU format of FIG. 30.

Fig. 35 is a flowchart showing a procedure of transmitting an NGV frame by the transmitting apparatus according to the present embodiment.

Fig. 36 is a flowchart showing a procedure of receiving an NGV frame by a receiving device according to the present embodiment.

Fig. 37 is a diagram for describing an apparatus for implementing the above-described method.

Fig. 38 illustrates a more specific wireless device for implementing embodiments of the present disclosure.

Detailed Description

Fig. 1 is a conceptual diagram illustrating the structure of a Wireless Local Area Network (WLAN).

The upper part of fig. 1 shows the structure of an infrastructure Basic Service Set (BSS) of Institute of Electrical and Electronics Engineers (IEEE) 802.11.

Referring to the upper part of fig. 1, the wireless LAN system may include one or more infrastructure BSSs (100, 105) (hereinafter referred to as BSSs). The BSS (100, 105), which is a set of an AP and an STA (e.g., an Access Point (AP) (125) and a station (STA1) (100-1)) that successfully synchronize to communicate with each other, is not a concept indicating a specific area. The BSS (105) may include one or more STAs (105-1, 105-2) that may join an AP (130).

The BSS may include at least one STA, an AP providing a distribution service, and a Distribution System (DS) (110) connecting a plurality of APs.

The distribution system (110) may implement an Extended Service Set (ESS) (140) that is extended by connecting multiple BSSs (100, 105). ESS (140) may be used as a term indicating a network configured by connecting one or more APs (125, 130) via a distribution system (110). APs included in one ESS (140) may have the same Service Set Identification (SSID).

The portal (120) may serve as a bridge to connect a wireless LAN network (IEEE 802.11) and another network (e.g., 802. X).

In the BSS shown in the upper part of fig. 1, a network between APs (125, 130) and a network between an AP (125, 130) and an STA (100-1, 105-2) may be implemented. However, the network is configured to perform communication between the STAs even without the AP (125, 130). A network in which communication is performed by configuring a network between STAs even without an AP (125, 130) is defined as an Ad-Hoc network or an Independent Basic Service Set (IBSS).

The lower part of fig. 1 shows a conceptual diagram showing IBSS.

Referring to the lower part of fig. 1, the IBSS is a BSS operating in the Ad-Hoc mode. Since the IBSS does not include an Access Point (AP), there is no centralized management entity performing management functions at the center. That is, in the IBSS, the STAs (150-1, 150-2, 150-3, 155-4, 155-5) are managed in a distributed manner. In an IBSS, all STAs (150-1, 150-2, 150-3, 155-4, 155-5) may be constituted by mobile STAs and are not allowed to access the DS to constitute a self-contained network.

An STA, which is a predetermined functional medium including a Medium Access Control (MAC) compliant with the specification of the Institute of Electrical and Electronics Engineers (IEEE)802.11 standard and a physical layer interface for a radio medium, may be used as meaning including all APs and non-AP Stations (STAs).

A STA may be referred to by various names such as a mobile terminal, wireless device, wireless transmit/receive unit (WTRU), User Equipment (UE), Mobile Station (MS), mobile subscriber unit, or user only.

Further, the term user may be used in various meanings, e.g., in wireless LAN communication, the term may be used to refer to STAs participating in uplink MU MIMO and/or uplink OFDMA transmissions. However, the meaning of the term is not limited thereto.

Fig. 2 is a diagram showing an example of a PPDU used in the IEEE standard.

As shown in FIG. 2, various types of PHY Protocol Data Units (PPDUs) may be used in standards such as IEEE a/g/n/ac. Specifically, the LTF and STF fields include training signals, SIG-a and SIG-B include control information for the receiving station, and the data field includes user data corresponding to the PSDU.

In an embodiment, an improved technique associated with a signal (alternatively, a control information field) for a data field of a PPDU is provided. The signals provided in the embodiments may be applied to a high efficiency ppdu (he ppdu) according to the IEEE802.11 ax standard. That is, the signals modified over embodiments may be HE-SIG-a and/or HE-SIG-B included in the HE PPDU. HE-SIG-a and HE-SIG-B may even be denoted as SIG-a and SIG-B, respectively. However, the improved signal proposed in the embodiment is not particularly limited to the HE-SIG-a and/or HE-SIG-B standards, and may be applied to control/data fields having various names including control information in a wireless communication system transmitting user data.

Fig. 3 is a diagram showing an example of the HE PDDU.

The control information field provided in an embodiment may be HE-SIG-B included in the HE PPDU. The HE PPDU according to fig. 3 is one example of a PPDU for multiple users, and a PPDU for only multiple users may include HE-SIG-B and a corresponding HE SIG-B may be omitted in a PPDU for a single user.

As shown in fig. 3, the HE-PPDU for a multi-user (MU) may include a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG), a high efficiency signal a (HE-SIG a), a high efficiency signal B (HE-SIG B), a high efficiency short training field (HE-STF), a high efficiency long training field (HE-LTF), a data field (alternatively, a MAC payload), and a Packet Extension (PE) field. The various fields may be transmitted during the illustrated time period (i.e., 4 μ s or 8 μ s).

The various fields of fig. 3 will be described in more detail below.

Fig. 4 is a diagram showing a layout of Resource Units (RUs) used in a frequency band of 20 MHz.

As shown in fig. 4, Resource Units (RUs) corresponding to different numbers of tones (tones), i.e., subcarriers, are used for some fields constituting the HE-PPDU. For example, resources may be allocated in units of RUs shown for HE-STF, HE-LTF, and data fields.

As shown in the uppermost portion of fig. 4, 26 units (i.e., units corresponding to 26 tones) may be arranged. The 6 tones may be used as guard bands in the leftmost band of the 20MHz band and the 5 tones may be used as guard bands in the rightmost band of the 20MHz band. Further, 7 DC tones may be inserted into the center band (i.e., DC band), and there may be 26 cells corresponding to 13 tones on the left and right sides of the DC band. The 26 units, 52 units, and 106 units may be allocated to other frequency bands. Each cell may be assigned to a receiving station (i.e., user).

Further, in addition to the multi-user (MU), the RU layout of fig. 4 may be used even in the case of a Single User (SU), and in this case, as shown in the lowermost part of fig. 4, one 242 units may be used, and in this case, three DC tones may be inserted.

In one example of fig. 4, RUs having various sizes are proposed (i.e., 26-RU, 52-RU, 106-RU, 242-RU, etc.), and as a result, embodiments are not limited to a specific size of each RU (i.e., the number of corresponding tones) since the specific size of the RU may be extended or increased.

Fig. 5 is a diagram showing a layout of Resource Units (RUs) used in a frequency band of 40 MHz.

Even in the example of fig. 5, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, and the like can be used, similarly to the case where an RU having various RUs is used in the example of fig. 4. Further, 5 DC tones may be inserted into the center frequency, 12 tones may be used as guard bands in the leftmost band of the 40MHz band, and 11 tones may be used as guard bands in the rightmost band of the 40MHz band.

In addition, as shown in FIG. 5, when the RU layout is for a single user, 484-RU may be used. That is, the specific number of RUs may be modified similarly to one example of fig. 4.

Fig. 6 is a diagram showing a layout of Resource Units (RUs) used in a frequency band of 80 MHz.

Even in one example of fig. 6, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, and the like can be used, similarly to the case where an RU having various RUs is used in the example of each of fig. 4 or 5. Further, 7 DC tones may be inserted into the center frequency, 12 tones may be used as guard bands in the leftmost band of the 80MHz band, and 11 tones may be used as guard bands in the rightmost band of the 80MHz band. In addition, a 26-RU may be used, which uses 13 tones located on each of the left and right sides of the DC band.

Further, as shown in fig. 6, when the RU layout is for a single user, 996-RU may be used, and in this case, 5 DC tones may be inserted.

Further, the specific number of RUs may be modified similarly to one example of each of fig. 4 or 5.

Fig. 7 is a diagram illustrating another example of the HE PPDU.

The block shown in fig. 7 is another example describing the HE-PPDU block of fig. 3 in terms of frequency.

The illustrated L-STF (700) may include short training Orthogonal Frequency Division Multiplexing (OFDM) symbols. The L-STF (700) may be used for frame detection, Automatic Gain Control (AGC), diversity detection, and coarse frequency/time synchronization.

The L-LTF (710) may include long training Orthogonal Frequency Division Multiplexing (OFDM) symbols. The L-LTF (710) may be used for fine frequency/time synchronization and channel prediction.

The L-SIG (720) may be used to transmit control information. The L-SIG (720) may include information about the data rate and data length. Further, the L-SIG may be repeatedly transmitted (720). That is, a new format (e.g., may be referred to as R-LSIG) may be configured in which the L-SIG (720) repeats.

The HE-SIG-a (730) may include control information common to the receiving stations.

In particular, HE-SIG-a (730) may include information about: 1) a DL/UL indicator, 2) a BSS color field indicating an identification of the BSS, 3) a field indicating a remaining time of a current TXOP period, 4) a bandwidth field indicating at least one of 20, 40, 80, 160, and 80+80MHz, 5) a field indicating an MCS technique applied to the HE-SIG-B, 6) an indication field regarding whether the HE-SIG-B is modulated by a dual subcarrier modulation technique for MCS, 7) a field indicating a number of symbols for the HE-SIG-B, 8) a field indicating whether the HE-SIG-B is configured for full bandwidth MIMO transmission, 9) a field indicating a number of symbols for the HE-LTF, 10) a field indicating a length of the HE-LTF and a CP length, 11) a field indicating whether an OFDM symbol exists for LDPC coding, 12) a field indicating control information related to Packet Extension (PE), and 13) a field indicating information on the CRC field of the HE-SIG-a, and the like. Specific fields of the HE-SIG-a may be added or partially omitted. Further, some fields of the HE-SIG-a may be partially added or omitted in other environments other than the multi-user (MU) environment.

Additionally, HE-SIG-a (730) may be composed of two parts: HE-SIG-a1 and HE-SIG-a 2. HE-SIG-a1 and HE-SIG-a2 included in HE-SIG-a may be defined by the following format structure (fields) according to PPDU. First, the HE-SIG-a field of the HE SU PPDU may be defined as follows.

[ Table 1]

In addition, the HE-SIG-a field of the HE MU PPDU may be defined as follows.

[ Table 2]

In addition, the HE-SIG-a field of the HE TB PPDU may be defined as follows.

[ Table 3]

As described above, the HE-SIG-B (740) may be included only in case of PPDU for Multiple Users (MU). In principle, the HE-SIG-a (750) or HE-SIG-B (760) may include resource allocation information (alternatively, virtual resource allocation information) for at least one receiving STA.

Fig. 8 is a block diagram illustrating one example of an HE-SIG-B according to an embodiment.

As shown in fig. 8, the HE-SIG-B field includes a common field at the foremost part, and the corresponding common field is separated from the field that follows to be encoded. That is, as shown in fig. 8, the HE-SIG-B field may contain a common field including common control information and a user-specific field including user-specific control information. In this case, the common field may include a CRC field or the like corresponding to the common field, and may be encoded as one BCC block. As shown in fig. 8, the following user-specific fields may be encoded as one BCC block including "user-specific fields" for 2 users and CRC fields corresponding thereto.

The previous field of the HE-SIG-B (740) may be transmitted in duplicate on the MU PPDU. In the case of the HE-SIG-B (740), the HE-SIG-B (740) transmitted in a certain frequency band (e.g., a fourth frequency band) may even include control information for a data field corresponding to the corresponding frequency band (i.e., the fourth frequency band) and a data field of another frequency band (e.g., a second frequency band) other than the corresponding frequency band. Further, a format may be provided in which HE-SIG-B (740) in a particular frequency band (e.g., the second frequency band) is repeated with HE-SIG-B (740) of another frequency band (e.g., the fourth frequency band). Alternatively, HE-SIG B may be transmitted in encoded form on all transmission resources (740). A field following the HE-SIG B (740) may include separate information for each receiving STA receiving the PPDU.

The HE-STF (750) may be used to improve automatic gain control estimation in a multiple-input multiple-output (MIMO) environment or an OFDMA environment.

The HE-LTF (760) may be used to estimate a channel in a MIMO environment or an OFDMA environment.

The size of Fast Fourier Transform (FFT)/Inverse Fast Fourier Transform (IFFT) applied to the fields after HE-STF (750) and the size of FFT/IFFT applied to the fields before HE-STF (750) may be different from each other. For example, the size of the FFT/IFFT applied to the HE-STF (750) and the fields after the HE-STF (750) may be four times the size of the FFT/IFFT applied to the fields before the HE-STF (750).

For example, when at least one field among L-STF (700), L-LTF (710), L-SIG (720), HE-SIG-A (730), and HE-SIG-B (740) on the PPDU of FIG. 7 is referred to as a first field, at least one of the data field (770), HE-STF (750), and HE-LTF (760) may be referred to as a second field. The first field may include fields associated with legacy systems and the second field may include fields associated with HE systems. In this case, a Fast Fourier Transform (FFT) size and an Inverse Fast Fourier Transform (IFFT) size may be defined as a size N (N is a natural number, for example, N ═ 1, 2, and 4) times the FFT/IFFT size used in the conventional wireless LAN system. That is, an FFT/IFFT having a size N (═ 4) times that of the first field of the HE PPDU may be applied. For example, 256FFT/IFFT may be applied to a bandwidth of 20MHz, 512FFT/IFFT may be applied to a bandwidth of 40MHz, 1024FFT/IFFT may be applied to a bandwidth of 80MHz, and 2048FFT/IFFT may be applied to a contiguous 160MHz or a non-contiguous 160MHz bandwidth.

In other words, the size of the subcarrier space/subcarrier spacing may be 1/N times the subcarrier space used in the conventional wireless LAN system (N is a natural number, e.g., N-4, and the subcarrier spacing is set to 78.125 kHz). That is, a subcarrier spacing having a size of 312.5kHz, which is a legacy subcarrier spacing, may be applied to a first field of the HE PPDU, and a subcarrier space having a size of 78.125kHz may be applied to a second field of the HE PPDU.

Alternatively, the IDFT/DFT period applied to each symbol of the first field may be expressed as 1/N (N-4) times the IDFT/DFT period applied to each data symbol of the second field. That is, the IDFT/DFT length applied to each symbol of the first field of the HE PPDU may be expressed as 3.2 μ s, and the IDFT/DFT length applied to each symbol of the second field of the HE PPDU may be expressed as 3.2 μ s × 4(═ 12.8 μ s). The length of the OFDM symbol may be a value obtained by adding the length of the Guard Interval (GI) to the IDFT/DFT length. The length of the GI may have various values such as 0.4. mu.s, 0.8. mu.s, 1.6. mu.s, 2.4. mu.s, and 3.2. mu.s.

For simplicity of explanation, in fig. 7, it is shown that the frequency band used by the first field and the frequency band used by the second field exactly coincide with each other, but in reality the two frequency bands may not exactly coincide with each other. For example, a main frequency band of a first field (L-STF, L-LTF, L-SIG, HE-SIG-A, and HE-SIG-B) corresponding to a first frequency band may be the same as a majority of a frequency band of a second field (HE-STF, HE-LTF, and data), but boundary faces of the respective frequency bands may not overlap with each other. As shown in fig. 4 to 6, since a plurality of null subcarriers, DC tones, guard tones, and the like are inserted during the placement of an RU, it may be difficult to precisely adjust the boundary surface.

A user (e.g., a receiving station) may receive HE-SIG-a (730) and may be instructed to receive downlink PPDU based on HE-SIG-a (730). In this case, the STA may perform decoding based on the FFT size changed from the HE-STF (750) and the fields after the HE-STF (750). Conversely, when the STA may not be indicated as receiving the downlink PPDU based on the HE-SIG-a (730), the STA may stop decoding and configure a Network Allocation Vector (NAV). A Cyclic Prefix (CP) of the HE-STF (750) may have a larger size than a CP of another field, and during the CP period, the STA may perform decoding for the downlink PPDU by changing an FFT size.

Hereinafter, in an embodiment of the present disclosure, data (alternatively, or frames) transmitted by an AP to an STA may be denoted as a term referred to as downlink data (alternatively, downlink frames), and data (alternatively, frames) transmitted by an STA to an AP may be denoted as a term referred to as uplink data (alternatively, uplink frames). Further, transmission from the AP to the STA may be denoted as downlink transmission, and transmission from the STA to the AP may be denoted as a term referred to as uplink transmission.

In addition, a PHY Protocol Data Unit (PPDU), a frame, and data transmitted through downlink transmission may be denoted as terms such as a downlink PPDU, a downlink frame, and downlink data, respectively. The PPDU may be a data unit including a PPDU header and a physical layer service data unit (PSDU), alternatively, a MAC Protocol Data Unit (MPDU). The PPDU header may include a PHY header and a PHY preamble, and the PSDU (alternatively, MPDU) may include a frame or an indication frame (alternatively, an information unit of a MAC layer) or a data unit indicating the frame. The PHY header may be denoted as a Physical Layer Convergence Protocol (PLCP) header as another term, and the PHY preamble may be denoted as a PLCP preamble as another term.

Also, PPDU, frame, and data transmitted through uplink transmission may be denoted as terms such as uplink PPDU, uplink frame, and uplink data, respectively.

In the wireless LAN system to which the embodiments of the present specification are applied, the total bandwidth may be used for downlink transmission to one STA and uplink transmission to one STA. Further, in the wireless LAN system to which the embodiments of the present specification are applied, the AP may perform Downlink (DL) multi-user (MU) transmission based on multiple input multiple output (MU MIMO), and the transmission may be expressed as a term referred to as DL MU MIMO transmission.

In addition, in the wireless LAN system according to the embodiment, a transmission method based on Orthogonal Frequency Division Multiple Access (OFDMA) is preferably supported for uplink transmission and/or downlink transmission. That is, data units (e.g., RUs) corresponding to different frequency resources are allocated to users to perform uplink/downlink communication. Specifically, in the wireless LAN system according to the embodiment, the AP may perform DL MU transmission based on OFDMA, and the transmission may be expressed as a term referred to as DL MU OFDMA transmission. When performing DL MU OFDMA transmission, the AP may transmit downlink data (alternatively, a downlink frame and a downlink PPDU) to a plurality of respective STAs through a plurality of respective frequency resources on overlapping time resources. The plurality of frequency resources may be a plurality of subbands (alternatively, subchannels) or a plurality of Resource Units (RUs). DL MU OFDMA transmission may be used with DL MU MIMO transmission. For example, DL MU MIMO transmission based on multiple space-time streams (alternatively, spatial streams) may be performed on a particular subband (alternatively, a subchannel) allocated for DL MU OFDMA transmission.

Further, in the wireless LAN system according to the embodiment, uplink multi-user (UL MU) transmission in which a plurality of STAs transmit data to the AP on the same time resource may be supported. Uplink transmission by multiple respective STAs on overlapping time resources may be performed in the frequency or spatial domain.

When uplink transmission by a plurality of respective STAs is performed on the frequency domain, resources of different frequencies may be allocated to the plurality of respective STAs as uplink transmission resources based on OFDMA. The different frequency resources may be different subbands (alternatively, subchannels) or different Resource Units (RUs). A plurality of corresponding STAs may transmit uplink data to the AP through different frequency resources. The transmission method by different frequency resources may be expressed as a term referred to as UL MU OFDMA transmission method.

When performing uplink transmission by a plurality of respective STAs on a spatial domain, different spatio-temporal streams (alternatively, spatial streams) may be allocated to the plurality of respective STAs, and the plurality of respective STAs may transmit uplink data to the AP through the different spatio-temporal streams. The transmission method by different spatial streams may be expressed as a term referred to as UL MU MIMO transmission method.

UL MU OFDMA transmission and UL MU MIMO transmission may be used together with each other. For example, UL MU MIMO transmission based on multiple space-time streams (alternatively, spatial streams) may be performed on specific subbands (alternatively, subchannels) allocated for UL MU OFDMA transmission.

In a conventional wireless LAN system that does not support MU OFDMA transmission, a multi-channel allocation method is used to allocate a wider bandwidth (e.g., a bandwidth exceeding 20MHz) to one terminal. When one channel unit is 20MHz, the plurality of channels may include a plurality of 20MHz channels. In the multi-channel allocation method, a primary channel rule is used to allocate a wider bandwidth to a terminal. When the primary channel rule is used, there is a limit to allocate a wider bandwidth to a terminal. Specifically, according to the primary channel rule, when a secondary channel adjacent to the primary channel is used in an overlapping bss (obss) and thus is busy, the STAs may use the remaining channels other than the primary channel. Therefore, since the STA may transmit a frame only to the primary channel, the transmission of the frame by the STA for a plurality of channels is limited. That is, in the conventional wireless LAN system, when high throughput is obtained by operating a wider bandwidth in the current wireless LAN environment where OBSS is not small, the main channel rule for allocating a plurality of channels may be a great limitation.

To solve this problem, in the embodiments, a wireless LAN system supporting the OFDMA technique is disclosed. That is, the OFDMA technique may be applied to at least one of the downlink and uplink. Also, the MU-MIMO technique may be additionally applied to at least one of a downlink and an uplink. When using OFDMA technology, multiple channels can be used simultaneously by not one terminal but multiple terminals, without being limited by the main channel rules. Accordingly, a wider bandwidth can be operated to improve efficiency of operating wireless resources.

As described above, in the case where uplink transmission performed by each of a plurality of STAs (e.g., non-AP STAs) is performed in the frequency domain, the AP may allocate different frequency resources corresponding to each of the plurality of STAs as uplink transmission resources based on OFDMA. In addition, as described above, the frequency resources different from each other may correspond to different subbands (or subchannels) or different Resource Units (RUs).

Different frequency resources corresponding to each of the plurality of STAs are indicated by the trigger frame.

Fig. 9 shows an example of a trigger frame. The trigger frame of fig. 9 allocates resources for uplink multi-user (MU) transmission and may be transmitted from the AP. The trigger frame may be configured as a MAC frame and may be included in a PPDU. For example, the trigger frame may be transmitted through the PPDU shown in fig. 3, through the legacy PPDU shown in fig. 2, or through a specific PPDU newly designed for the corresponding trigger frame. In case that the trigger frame is transmitted through the PPDU of fig. 3, the trigger frame may be included in a data field shown in the drawing.

Each field shown in fig. 9 may be partially omitted, or other fields may be added. Further, the length of each field may vary differently than as shown.

The frame control field (910) shown in fig. 9 may include information on a version of a MAC protocol and other additional control information, and the duration field (920) may include time information for configuring a NAV or information on an identifier (e.g., AID) of the user equipment.

In addition, the RA field (930) includes address information of a receiving STA of a corresponding trigger frame, and may be omitted if necessary. The TA field (940) includes address information of STAs (e.g., APs) that trigger the corresponding trigger frame, and the common information field (950) includes common control information applied to a receiving STA that receives the corresponding trigger frame. For example, a field indicating the length of an L-SIG field of the UL PPDU transmitted in response to the corresponding trigger frame or information controlling the content of a SIG-a field (i.e., HE-SIG-a field) of the UL PPDU transmitted in response to the corresponding trigger frame may be included. Also, as the common control information, information on the length of a CP of the UP PPDU transmitted in response to a corresponding trigger frame or information on the length of an LTF field may be included.

In addition, it is preferable to include per-user information fields (960#1 to 960# N) corresponding to the number of receiving STAs which receive the trigger frame of fig. 9. The per-user information field may be referred to as an "RU allocation field".

In addition, the trigger frame of fig. 9 may include a padding field (970) and a frame check sequence field (980).

It is preferable that each of the per-user information fields (960#1 to 960# N) shown in fig. 9 includes a plurality of subfields.

Fig. 10 shows an example of the common information field. Among the subfields of fig. 10, some subfields may be omitted, and other additional subfields may also be added. In addition, the length of each subfield shown in the drawing may vary.

The trigger type field (1010) of fig. 10 may indicate a trigger frame variant (trigger frame variable) and an encoding of the trigger frame variant. The trigger type field (1010) may be defined as follows.

[ Table 4]

The UL BW field (1020) of fig. 10 indicates the bandwidth in the HE-SIG-a field of a HE Trigger (TB) based PPDU. The UL BW field (1020) may be defined as follows.

[ Table 5]

UL BW subfield value	Description of the invention
		0	20MHz
1	40MHz
		2	80MHz
3	80+80MHz or 160MHz

The Guard Interval (GI) and LTF type field (1030) of fig. 10 indicates the GI and HE-LTF type of the HE TB PPDU response. The GI and LTF type fields (1030) may be defined as follows.

[ Table 6]

GI and LTF field values	Description of the invention
		0	1x HE-LTF+1.6μs GI
1	2x HE-LTF+1.6μs GI
		2	4x HE-LTF+3.2μs GI(#15968)
3	Retention

Further, when the GI and LTF type field (1030) has a value of 2 or 3, the MU-MIMO LTF mode field (1040) of fig. 10 indicates the LTF mode of the UL MU-MIMO HE TB PPDU response. At this time, the MU-MIMO LTF mode field (1040) may be defined as follows.

The MU-MIMO LTF mode field (1040) indicates one of an HE single stream pilot HE-LTF mode or an HE masked HE-LTF sequence mode if the trigger frame is allocated an RU occupying the entire HE TB PPDU bandwidth and allocated to one or more STAs.

The MU-MIMO LTF mode field (1040) indicates an HE single stream pilot HE-LTF mode if the trigger frame does not allocate an RU occupying the entire HE TB PPDU bandwidth and the RU is not allocated to one or more STAs. The MU-MIMO LTF mode field (1040) may be defined as follows.

[ Table 7]

Fig. 11 shows an example of subfields included in the per-user information field. Among the subfields of fig. 11, some subfields may be omitted, and other additional subfields may also be added. In addition, the length of each subfield shown in the drawing may vary.

The user identifier field (or AID12 field, 1110) of fig. 11 indicates an identifier of an STA (i.e., a receiving STA) corresponding to per-user information, where an example of the identifier may be the entire AID or a portion of the AID.

Further, an RU allocation field (1120) may be included. In other words, when the receiving STA identified by the user identifier field (1110) transmits an UL PPDU in response to the trigger frame of fig. 9, the corresponding UL PPDU is transmitted through an RU indicated by the RU allocation field (1120). In this case, preferably, the RU indicated by the RU allocation field (1120) indicates the RU shown in fig. 4, 5 and 6. The specific structure of the RU allocation field (1120) will be described later.

The subfields of fig. 11 may include a (UL FEC) coding type field (1130). The coding type field (1130) may indicate a coding type of an uplink PPDU transmitted in response to the trigger frame of fig. 9. For example, the coding type field (1130) may be set to "1" when BCC coding is applied to the uplink PPDU, and the coding type field (1130) may be set to "0" when LDPC coding is applied.

In addition, the subfield of fig. 11 may include an UL MCS field (1140). The MCS field (1140) may indicate an MCS scheme applied to an uplink PPDU transmitted in response to the trigger frame of fig. 9.

In addition, the subfield of fig. 11 may include a trigger-related user information field (1150). When the trigger type field (1010) of fig. 10 indicates the basic trigger variant, the trigger related user information field (1150) may include an MPDU MU spacing factor subfield (2 bits), a TID aggregation limit subfield (3 bits), a reserved field (1 bit), and a preferred AC subfield (2 bits).

Hereinafter, the present disclosure proposes an example of improving a control field included in a PPDU. The improved control field according to the present disclosure includes a first control field including control information required to interpret (interpret) a PPDU and a second control field including control information for demodulating a data field of the PPDU. The first control field and the second control field may be used for various fields. For example, the first control field may be the HE-SIG-a (730) of fig. 7, and the second control field may be the HE-SIG-B (740) shown in fig. 7 and 8.

Hereinafter, specific examples of improving the first control field or the second control field will be described.

In the following examples, a control identifier inserted into the first control field or the second control field is proposed. The size of the control identifier may vary, and may be implemented with 1 bit of information, for example.

When, for example, 20MHz transmission is performed, a control identifier (e.g., a 1-bit identifier) may indicate whether a 242-type RU is allocated. As shown in fig. 4-6, various sizes of RUs may be used. These RUs can be roughly classified into two types. For example, all of the RUs shown in fig. 4 to 6 may be classified into a 26-type RU and a 242-type RU. For example, a 26-type RU may include 26-RUs, 52-RUs, and 106-RUs, while a 242-type RU may include 242-RUs, 484-RUs, and larger RUs.

A control identifier (e.g., a 1-bit identifier) may indicate that a 242-type RU has been used. In other words, the control identifier may indicate that 242-RUs, 484-RUs, or 996-RUs are included. If the transmission band in which the PPDU is transmitted has a bandwidth of 20MHz, the 242-RU is a single RU corresponding to the full bandwidth (i.e., 20MHz) of the transmission band. Accordingly, a control identifier (e.g., a 1-bit identifier) may indicate whether a single RU corresponding to the full bandwidth of the transmission band is allocated.

For example, if the bandwidth of the transmission band is 40MHz, the control identifier (e.g., a 1-bit identifier) may indicate whether a single RU corresponding to the full bandwidth of the transmission band (i.e., a bandwidth of 40 MHz) has been allocated. In other words, the control identifier may indicate whether the 484-RU has been allocated for transmission in a frequency band having a bandwidth of 40 MHz.

For example, if the bandwidth of the transmission band is 80MHz, the control identifier (e.g., a 1-bit identifier) may indicate whether a single RU corresponding to the full bandwidth of the transmission band (i.e., a bandwidth of 80 MHz) has been allocated. In other words, the control identifier may indicate whether the 996-RU has been allocated for transmission in a frequency band having a bandwidth of 80 MHz.

Various technical effects may be achieved by a control identifier (e.g., a 1-bit identifier).

First, when a single RU corresponding to the full bandwidth of a transmission band is allocated by a control identifier (e.g., a 1-bit identifier), allocation information of the RU may be omitted. In other words, since only one RU is allocated over the entire transmission band instead of a plurality of RUs, allocation information of RUs may be intentionally omitted.

Furthermore, the control identifier may be used as signaling for full bandwidth MU-MIMO. For example, when a single RU is allocated over the full bandwidth of the transmission band, multiple users may be allocated to the corresponding single RU. In other words, even if the signal for each user is not unique in the time and spatial domains, other techniques (e.g., spatial multiplexing) may be used to multiplex the signals for multiple users in the same single RU. Thus, a control identifier (e.g., a 1-bit identifier) may also be used to indicate whether full bandwidth MU-MIMO as described above is used.

The common field included in the second control field (HE-SIG-B, 740) may include an RU allocation subfield. The common field may include a plurality of RU allocation subfields (including N RU allocation subfields) according to a PPDU bandwidth. The format of the common fields may be defined as follows.

[ Table 8]

The RU allocation subfield included in the common field of the HE-SIG-B may be configured with 8 bits and may be indicated as follows for a 20MHz PPDU bandwidth. The RU to be used as the data part in the frequency domain is allocated using an index for the RU size and a setting in the frequency domain. The mapping between the 8-bit RU allocation subfield for RU allocation and the number of users per RU can be defined as follows.

[ Table 9]

The user-specific fields included in the second control field (HE-SIG-B, 740) may include a user field, a CRC field, and a tail field. The format of the user-specific fields may be defined as follows.

[ Table 10]

Further, the user-specific field of the HE-SIG-B is composed of a plurality of user fields. The plurality of user fields are located after the common field of the HE-SIG-B. The position of the RU allocation subfield of the common field and the position of the user field of the user specific field are used together to identify an RU for transmitting data of the STA. Multiple RUs designated as a single STA are now allowed in the user specific field. Thus, signaling allowing a STA to decode its own data is sent in only one user field.

As an example, it may be assumed that the RU allocation subfield is configured with 01000010 of 8 bits to indicate that five 26-tone RUs are arranged beside one 106-tone RU and that three user fields are included in the 106-tone RU. At this time, the 106-tone RU may support multiplexing of the three users. The example may indicate that eight user fields included in the user-specific field are mapped to six RUs, the first three user fields being allocated according to the MU-MIMO scheme in the first 106 tone RUs and the remaining five user fields being allocated to each of the five 26 tone RUs.

The user field included in the user-specific field of the HE-SIG-B may be defined as follows. First, the user fields allocated for non-MU-MIMO are as follows.

[ Table 12]

The user fields allocated for MU-MIMO are as follows.

[ Table 13]

Fig. 12 shows an example of a HE TB PPDU. The PPDU of fig. 12 shows an uplink PPDU transmitted in response to the trigger frame of fig. 9. At least one STA receiving the trigger frame from the AP may check the common information field and the individual user information field of the trigger frame and may transmit the HE TB PPDU simultaneously with another STA having received the trigger frame.

As shown, the PPDU of fig. 12 includes various fields, each of which corresponds to the fields shown in fig. 2, 3 and 7. Further, as shown, the HE TB PPDU (or uplink PPDU) of fig. 12 may not include the HE-SIG-B field but only the HE-SIG-a field.

1. Carrier sense multiple access/collision avoidance (CSMA/CA)

In IEEE802.11, communication is implemented in a shared wireless medium, and thus has fundamentally different characteristics from a wired channel environment. For example, communication may be based on carrier sense multiple access/collision detection (CSMA/CD) in a wired channel environment. For example, when a signal is transmitted once in Tx, the signal is transmitted to Rx without significant signal attenuation since the channel environment does not change much. In this case, when a collision occurs between two or more signals, the collision is detectable. This is because the detected power in Rx is instantaneously (instant) larger than the power transmitted in Tx. However, in a wireless channel environment, the channel is affected by various factors (for example, the signal may be greatly attenuated according to distance or may instantaneously experience deep fading), and carrier sensing cannot be correctly implemented in Tx for whether the signal is actually correctly transmitted in Rx or whether there is collision. Thus, a Distributed Coordination Function (DCF) was introduced in 802.11 as a carrier sense multiple access/collision avoidance (CSMA/CA) mechanism. Herein, a Station (STA) having data to transmit performs a Clear Channel Assessment (CCA) for listening to a medium during a specific duration (e.g., DCF interframe space (DIFS)) before transmitting the data. In this case, if the medium is idle, the STA can transmit data by using the medium. On the other hand, if the medium is busy, data may be transmitted after waiting for a random backoff period in addition to the DIFS, assuming that several STAs have waited to use the medium. In this case, a random backoff period may make collisions avoidable because each STA has probabilistically a different backoff interval, and thus does not end up having a different transmission time, assuming there are several STAs used to transmit data. When one STA starts transmitting, other STAs cannot use the medium.

The random back-off time and procedure will be briefly described as follows. When a particular medium transitions from busy to idle, several STAs begin to prepare for data transmission. In this case, to minimize collisions, STAs intending to transmit data select respective random backoff counts and wait for those slot times. The random backoff count is a pseudo-random integer value and is in [0CW ]]One of the evenly distributed values is selected. Herein, CW denotes a contention window. The CW parameter has a CWMin value as an initial value and when transmission fails, the valueIt will double. For example, if an ACK response is not received in response to a transmitted data frame, a collision may be considered to have occurred. If the CW value has a CWmax value, the CWmax value is maintained until the data transmission is successful, and when the data transmission is successful, the CWmax value is reset to the CWmin value. In this case, for ease of implementation and operation, the values CW, CWmin and CWmax are preferably kept at 2ⁿ-1. Furthermore, if the random backoff procedure starts, the STA is in [0CW ]]A random backoff count is selected within the range and the medium is then continuously monitored while the backoff slot is being counted down. Meanwhile, the countdown is stopped if the medium enters a busy state, and the countdown of the remaining backoff slots is resumed when the medium returns to an idle state.

PHY Process

The PHY transmit/receive process in Wi-Fi is as follows, but the specific packet configuration method may be different. For convenience, only 11n and 11ax are used as examples, but a similar process is followed for 11 g/ac.

That is, in the PHY transmission process, a MAC Protocol Data Unit (MPDU) or an aggregate MPDU (a-MPDU) transmitted from the MAC side is converted into a single PHY Service Data Unit (PSDU) at the PHY side and transmitted by inserting a preamble, a tail bit, and a padding bit (optional), and this is called a PPDU.

The PHY reception process is generally as follows. When performing energy detection and preamble detection (L/HT/VHT/HE preamble detection for each Wi-Fi version), information on PSDU configuration is obtained from a PHY header (L/HT/VHT/HE-SIG) to read a MAC header and then read data.

MAC header

Fig. 13 shows a MAC frame format used in the wireless LAN system.

The MAC frame format (1310) includes a set of fields generated in a fixed order in all frames. Fig. 13 shows a general MAC frame format. The first three fields (frame control, duration/ID and address 1) and the last Field (FCS) together constitute the minimum frame format and are present in all frames including the reserved type and subtype. Address 2, address 3, sequence control, address 4, QoS control, HT control, and frame body fields are present only in a specific frame type and lower types.

In addition, fig. 13 shows a frame control field (1320) included in the MAC frame format.

The first three subfields of the frame control field (1320) are protocol version, type, and subtype. The remaining subfields of the frame control field may vary depending on the configuration of the type and subtype subfields.

The remaining subfields of the frame control field include to DS, from DS, more fragments, retry, power management, more data, protected frame, and + HTC/sequence subfield if the type subfield value is not equal to 1, or if the subtype subfield value is not equal to 6. In this case, the format of the frame control field is as shown in the lower part of fig. 13.

In case the type subfield value is equal to 1, or if the value of the subtype subfield is equal to 6, the remaining subfields of the frame control field include control frame extension, power management, more data, protected frame and + HTC/sequence subfields (not shown).

4. Aggregate MPDU (A-MPDU)

Fig. 14 shows an a-MPDU format used in the wireless LAN system.

As shown in fig. 14, the a-MPDU (1410) is composed of a sequence of one or more a-MPDU sub-frames having various sizes and EOF padding.

In addition, fig. 14 shows the structure of an a-MPDU sub-frame (1420). Each a-MPDU sub-frame (1420) is made up of MPDU delimiters (1440) that are optionally followed (concatenated) by MPDUs. Each non-final a-MPDU sub-frame of the a-MPDU additionally comprises padding octets (padding octets) such that the length of the sub-frame is a multiple of the 4 octet length. The content of such octets is not yet determined.

In the HT PPDU, the last a-MPDU subframe is not padded.

In addition, fig. 14 also shows an EOF padding field (1430). The EOF padding field is present only in the VHT PPDU.

The EOF padding sub-frame subfield includes zero (0) or more EOF padding sub-frames. The EOF padding subframe is an a-MPDU subframe having 0 in the MPDU length field and 1 in the EOF field.

In the VHT PPDU, padding may be determined according to the following rule.

0-3 octets in the padding subfield of the last a-MPDU sub-frame before the EOF padding sub-frame (see 1430 of fig. 14). The contents of these octets are unspecified.

There are 0 or more EOF padding subframes in the EOF padding subframes EOF subfield.

0-3 octet EOF padding octets subfield. The contents of these octets are unspecified.

The a-MPDU pre-EOF padding corresponds to a-MPDU content not included in the EOF padding field. To meet the minimum MPDU start interval requirement, the a-MPDU pre-EOF padding includes all a-MPDU subframes having 0 in the MPDU length field and 0 in the EOF field.

In addition, fig. 14 also shows an MPDU delimiter (1440). The MPDU delimiter (1440) has a length of 4 octets, and the MPDU delimiter (1440) of fig. 14 shows the structure of the MPDU delimiter transmitted by a non-DMG STA. The structure of the MPDU delimiter transmitted by the DMG STA is a structure (not shown) in which the EOF subfield is removed from the MPDU delimiter transmitted by a non-DMG STA.

The contents of the MPDU delimiter (1440) (non-DMG) may be defined as follows.

[ Table 14]

5. Special short-range communication (DSRC)

The 5.9GHz DSRC is a medium-short range communication service that supports both public safety and private operations in roadside-to-vehicle and vehicle-to-vehicle communication environments. DSRC is designed to complement cellular communications by providing very high data transfer rates where it is important to minimize latency of the communication link and isolate relatively small communication areas. In addition, the PHY and MAC protocols are based on modifications of ieee802.11p for Wireless Access (WAVE) in a vehicle environment.

<IEEE 802.11p>

802.11p uses the 802.11a PHY by performing 2-fold downcoming (downcoming) on the PHY. That is, 802.11p transmits signals by using a 10MHz bandwidth instead of a 20MHz bandwidth. The parameter sets for comparing 802.11a and 802.11p are as follows.

[ Table 15]

Figure 15 shows a band plan for a 5.9GHz DSRC. The channels of the DSRC band include a control channel and a service channel, and each channel is capable of performing data transmission at 3, 4.5, 6, 9, 12, 18, 24, and 27 Mbps. If there is an optional channel of 20MHz, transmission of 6, 9, 12, 18, 24, 36, 48, and 54Mbps can be performed. All services and channels should support 6, 9 and 12 Mbps. And, in case of a control channel, although the preamble is 3Mbps, the message itself is 6 Mbps. Where channels 174 and 176 and channels 180 and 182 are authorized by a frequency management organization, the channel groups may be 20MHz channels 175 and 181, respectively. The remaining channels should be reserved for future use. Short messages or notification data and public safety alarm data etc. are broadcast to all On Board Units (OBUs) over a control channel. To maximize service efficiency and quality and reduce interference between services, the control channel and the service channel have been isolated.

The channel number 178 is a control channel that automatically performs searching and receives notification or data transmission and warning messages and the like from roadside units (RSUs). All data of the control channel should be transmitted within 200ms and repeated with a predetermined period. In the control channel, public safety warnings have the highest priority than any other private message. Private messages of more than 200ms are sent over the service channel.

Private messages or longer public safety messages, etc. are sent over the service channel. To prevent collision (or collision), a scheme for detecting a channel status, i.e., Carrier Sense Multiple Access (CSMA), is used before transmission.

Hereinafter, EDCA parameters in BSS external environment (OCB) mode will be defined. The OCB mode represents a state in which direct communication between nodes can be performed without any procedure associated with an AP. The basic EDCA parameter set for STA operation with dot11 ocbarctivated as true is shown below.

[ Table 16]

AC	CWmin	CWmax	AIFSN	TXOP limitation
					AC_BK	aCWmin	aCWmax	9	0
AC_BE	aCWmin	aCWmax	6	0
					AC_VI	(aCWmin+1)/2-1	aCWmin	3	0
AC_VO	(aCWmin+1)/4-1	(aCWmin+1)/2-1	2	0

The OCB mode is characterized as follows.

In the MAC header, to/from DS field is 0

Address

-single or group destination MAC address

-BSSID field ═ wildcard BSSID

-address 1: RA, address 2: TA, address 3: wildcard BSSID

Service without IEEE802.11 authentication, association, or data confidentiality

TXOP limit of 0

Using TC (TID) only

STAs need not be synchronized to a common clock or use these mechanisms

The STA may keep the TSF timer for purposes other than synchronization

STA may send action frame and if STA keeps TSF timer, may send timing advertisement frame STA may send control frame except for control frame of subtype PS-Poll, CF-End and CF-End + CFAck

The STA may transmit data frames of the subtype data, null, QoS data and QoS null

STAs with dot11 OCBActive equal to true should not join or start BSS

6. Embodiments applicable to the present disclosure

Next Generation Vehicle (NGV) systems proposed to improve 2 times throughput and support high speed can transmit signals by using a wide bandwidth, compared to 11p systems for V2X of 5.9GHz band. The present specification proposes a method for configuring a frame format for transmitting a signal by using a 20MHz bandwidth in order to achieve enhanced performance in an NGV.

In order that V2X can be easily supported on the 5.9GHz band, technology development for NGV is being performed in consideration of improvement in throughput and high-speed support of DSRC (11p), and in order to achieve 2-fold improvement in throughput, wide-bandwidth (20MHz) transmission is being considered instead of conventional 10MHz transmission. Further, the NGV channel supports at least one operation of interoperability/backward compatibility/coexistence with conventional 11 p. Therefore, a 20MHz frame format for supporting the above operation and transmitting a signal by using a 20MHz bandwidth is required. This specification presents a method for configuring a frame format for 20MHz transmission.

An 802.11p packet supporting vehicle-to-vehicle communication of the 5.9GHz band may be configured by applying the OFDM parameter set of 11a for the 10MHz band, and the packet uses the frame format shown in fig. 16.

Fig. 16 shows a frame format of an 802.11p system.

As shown in fig. 16, the 11p frame is composed of an STF for synchronization and AGC, an LTF for channel estimation, and a Signal (SIG) field including information on a data field. In addition, in fig. 16, the data field includes a service field, and the service field is composed of 16 bits.

Since the 11p frame is configured by applying the same set of OFDM parameters as 11a for the 10MHz band, the symbol duration of the 11p frame (where one symbol duration is equal to 8us) is longer than 11 a. That is, the length of the 11p frame is twice as long as the 11a frame in terms of time.

Frame format of NGV

Fig. 17 shows an example of an NGV PPDU format.

Compared to 11p using the frame format of fig. 16, a 10MHz NGV frame proposed for improving throughput and supporting high speed may be configured as shown in fig. 17. The NGV PPDU of fig. 17 may include a preamble portion of 11p for backward compatibility with 11 p.

As shown in fig. 17, in order to achieve backward compatibility with 11p using a 5.9GHz band, a frame is configured by placing STF, LTF, and SIG (L-STF, L-LTF, and L-SIG of fig. 17) constituting a preamble of 11p at the beginning (or foremost) of the frame. In addition, the frame may be configured of NGV data and NGV-SIG, NGV-STF, NGV-LTF, and the like constituting NGV-SIG including control information for NGV after L-SIG.

Fig. 17 is only an example of an NGV frame format. Also, it can be considered to add an OFDM symbol for NGV frame differentiation after the L part (L-STF, L-LTF, and L-SIG). That is, the NGV frame format may be configured to have the structure shown in fig. 18.

Fig. 18 shows another example of an NGV PPDU format.

In addition, the frame may be configured by placing an OFDM symbol for indicating an NGV frame format or for indicating information on an NGV frame in front of an NGV control field. At this time, the number of symbols placed in front of the NGV-SIG may be equal to 1 or more, and the symbol may be a symbol (RL-SIG) in which L-SIG is repeated.

As shown in fig. 18, the NGV portion (NGV-STF, NGV-LTF, NGV data) may be constituted by symbols having the same symbol length as 11p (i.e., 156.25kHz), or may be constituted by symbols having a longer symbol length than 11p symbols (i.e., 78.125 kHz).

Fig. 19 shows yet another example of an NGV PPDU format.

Unlike fig. 17 and 18, to fully support interoperability with 11p, NGV frames or NGV PPDUs may be transmitted via 11p transmissions, i.e., without detection (e.g., preamble detection, packet detection) to the 11p PPDU or without the presence of 11p devices. As described above, as shown in fig. 19, in the case where there is no signal transmission for an 11p device in a channel, or in the case where there is no 11p device using a corresponding channel, the NGV frame format may be configured the same as the conventional 11p frame format. At this time, the NGV frame format may be configured by using a tone plan other than the tone plan (tone plan) of 11 p. For example, NGV 10MHz transmission may be performed by applying 2x Downconversion (DC) to an 11ac 20MHz tone plan.

As described above, since NGV uses an available tone number greater than 11p, in order to perform channel estimation on such tones, additional tones are added to the L-SIG and then transmitted. At this point, the index of the extra tone is (-28-272728).

Further, in fig. 19, in order to perform packet classification on the 11bd frame, L-SIG (RL-SIG) may be repeatedly placed after L-SIG. Subsequently, an NGV-SIG field including information about 11bd transmission may be placed in order to configure the 11bd frame. At this time, an extra tone may also be added to the repeated L-SIG (RL-SIG), and the NGV-SIG may transmit information by using the same number of available tones as the added extra tone. At this time, the tone index of the extra tone is [ -28-272728 ]. Also, since the receiving end can obtain a combining gain by repeatedly transmitting L-SIG, it would be advantageous in expanding the range for 11bd transmission.

Based on the frame format for 10MHz transmission, a frame format for transmitting a signal by using a 20MHz bandwidth may be configured as follows. That is, the 20MHz NGV frame format may be configured based on the 10MHz NGV frame format shown in fig. 17 and 18.

1) Utilizing conventional wide bandwidth frame formats

Fig. 20 shows an example of an NGV PPDU format transmitted in a 20MHz band.

The L sections (L-STF, L-LTF, and L-SIG) and the NGV-SIG are configured to have a replica structure in units of 10MHz channels, and the NGV sections (NGV-STF, NGV-LTF, NGV data) are configured based on the full 20 MHz.

i. The NGV portion configured by using the full band (i.e., 20MHz) can be configured as follows.

The i-1.NGV portion can be configured without downconversion by reusing the 11ac 20MHz format.

The i-2.NGV portion can be configured by performing 2x downconversion on an 11ac 40MHz format.

The i-3.NGV portion can be configured by performing 4x downconversion on an 11ac 80MHz format.

B. Since the NGV part is transmitted by using a wide bandwidth, information on the BW is transmitted through the NGV-SIG field, and the NGV-STA can decode the frame format according to the bandwidth through the received information.

C. The frame format for 20MHz bandwidth transmission configured as described above may be configured as shown in fig. 20.

D. As described above, the NGV portion (NGV-STF, NGV-LTF, NGV data) may be configured by using the same OFDM parameter set (i.e., subcarrier spacing of 156.25kHz) as the legacy portion (11p preamble portion) or by using a parameter set having a symbol length 2 times that of the legacy portion (i.e., subcarrier spacing of 78.125 kHz). Also, in the frame, since the L part always exists in front of the NGV part and since the L part is always transmitted before the NGV part, the NGV STA can apply information on AGC and channel estimation and the like, which have been performed by using the received L part, to the NGV part. Therefore, 20MHz channel transmission can be performed by using a frame format different from the above-described frame format.

Fig. 21 shows another example of an NGV PPDU format transmitted in a 20MHz band.

Additionally, in an NGV PPDU, repeated L-SIG (RL-SIG) symbols may be placed in front of the NGV-SIG for range extension and PPDU differentiation. To transmit a larger amount of information over the NGV-SIG, additional tones may be used. Also, herein, extra tones may be used for channel estimation and may be added to the L-SIG and repeated L-SIG (RL-SIG) symbols. At this time, the tone index of the extra tone is [ -28-272728 ]. The frame format for 20MHz bandwidth transmission configured as described above may be configured as shown in fig. 21.

E. In addition, 11bd can perform 20MHz channel transmission by using a frame format different from the above-described frame format.

Fig. 22 shows an example of an NGV PPDU format transmitted in a 20MHz band and not including NGV-STF.

i. Frame format not including NGV-STF

i-1. when performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform AGC for 20MHz by using the L-STF. Therefore, in the case where the NGV section uses the same parameter set as the conventional section, AGC estimation does not need to be additionally performed in the NGV section. In addition, even though the NGV portion has been configured by using a different set of parameters (e.g., 4x DC), since power control can be performed by using AGC obtained by using a conventional (or existing) L-STF, no additional AGC estimation needs to be performed on the NGV portion. Therefore, in this case, it is not necessary to configure the NGV-STF, and therefore, the frame format can be configured as shown in fig. 22. In addition, since 11bd does not perform MIMO transmission, power control per reception antenna is not required. Therefore, it is not necessary to additionally configure the STF.

i-2. therefore, in this case, the NGV-STF does not need to be configured, and therefore, the frame format can be configured as described above.

i-3 since a separate NGV-STF is not configured for AGC estimation, frame overhead can be reduced.

i-4 in fig. 22, NGV-SIG can be modulated based on Q-BPSK.

i-5. in the structure of fig. 22, NGV-SIG is only an example. And thus, the L-SIG may be repeated, or an OFDM symbol based on Q-BPSK modulation for 11bd PPDU discrimination may be placed instead of the NGV-SIG symbol. In addition, a repeated L-SIG or one OFDM symbol based on Q-BPSK modulation may be placed in front of the NGV-SIG symbol.

Fig. 23 shows an example of an NGV PPDU format transmitted in a 20MHz band and not including NGV-LTFs.

Frame format without NGV-LTF

When performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform channel estimation for 20MHz by using the L-LTF. Therefore, in the case where the NGV section uses the same parameter set as the conventional section, it is not necessary to additionally perform channel estimation in the NGV section. If the NGV portion is configured by using a different set of parameters (e.g., 4x DC), since the tone spacing is 1/2, the channel estimation value obtained by using the existing L-LTF can be applied to two carriers. And, therefore, there is no need to configure the NGV-LTF in order to perform additional channel estimation on the NGV portion. In addition, the channel can be estimated by using the NGV-STF. Therefore, in this case, it is not necessary to configure the NGV-LTF for channel estimation, and therefore, the frame format may be configured as shown in fig. 23.

And ii-2, since a separate NGV-LTF is not configured for channel estimation, frame overhead can be reduced.

in fig. 23, NGV-SIG may be modulated based on Q-BPSK.

ii-4. in FIG. 23, NGV-SIG is an example only. And thus, the L-SIG may be repeated, or an OFDM symbol based on Q-BPSK modulation for 11bd PPDU discrimination may be placed instead of the NGV-SIG symbol. In addition, a repeated L-SIG (RL-SIG) or one OFDM symbol based on Q-BPSK modulation may be placed in front of the NGV-SIG symbol.

Fig. 24 shows an example of an NGV PPDU format transmitted in a 20MHz band and excluding NGV-STF and NGV-LTF.

Frame formats excluding NGV-STF and NGV-LTF

When performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform AGC and channel estimation on 20MHz by using the L-STF and the L-LTF. Therefore, in the case where the NGV section uses the same parameter set as the conventional section, AGC estimation and channel estimation do not need to be additionally performed in the NGV section. In the case where the NGV portion is configured by using a different set of parameters (e.g., 4x DC), the AGC estimate and channel estimation information obtained by using the existing L-STF and L-LTF may be used by applying to the NGV portion by the tone spacing of 1/2. For example, in the case of configuring NGV data by using 4x DC, since the tone spacing becomes 1/2 of the L part, almost no change occurs in the channel according to the frequency. Accordingly, data can be estimated by applying information on a channel estimated for a carrier by using L-LTF to 2 subcarriers of an NGV data part. As described above, since information estimated by using the L-STF and the L-LTF can be used, it is not necessary to configure NGV-STF and NGV-LTF for AGC estimation and channel estimation. And, therefore, the frame format can be configured as shown in fig. 24.

iii-2 since separate NGV-STF and NGV-LTF are not configured for AGC estimation and channel estimation, frame overhead can be reduced.

in FIG. 24, NGV-SIG can be modulated based on Q-BPSK.

Fig. 25 shows another example of an NGV PPDU format transmitted in a 20MHz band and not including NGV-STF and NGV-LTF.

in FIG. 24, NGV-SIG is an example only. And thus, the L-SIG may be repeated, or an OFDM symbol based on Q-BPSK modulation for 11bd PPDU discrimination may be placed instead of the NGV-SIG symbol. In addition, a repeated L-SIG (RL-SIG) or one OFDM symbol based on Q-BPSK modulation may be placed in front of the NGV-SIG symbol. At this time, as shown in fig. 25, a frame format having a repeated L-SIG (RL-SIG) placed in front of an NGV-SIG symbol may be configured.

Fig. 26 shows an example of an NGV PPDU format transmitted in a 20MHz band and composed of only an L section and NGV data.

in the case of consisting of only an L portion and an NGV data portion:

iv-1. when performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform AGC and channel estimation on 20MHz by using the L-STF and the L-LTF. Therefore, in the case where the NGV section uses the same parameter set as the conventional section, there is no need to additionally perform AGC estimation and channel estimation. Therefore, NGV-STF and NGV-LTF can be omitted.

Fig. 27 shows an example of a tone plan for the NGV PPDU format of fig. 26.

Fig. 28 shows another example of a tone plan for the NGV PPDU format of fig. 26.

iv-2. as shown in fig. 27 and 28, since the legacy portion is duplicated in units of 10MHz, and since the NGV data portion is transmitted using the entire bandwidth, the available tones for the L-SIG and data may be different. Thus, additional tones may be used by adding additional tones to the L-SIG in order to perform channel estimation for the available tones used in performing NGV data transmissions. For example, when performing 10MHz transmission, if NGV data uses an 11ac 20MHz tone scheme, the 4 extra tones may be transmitted by adding them to the L-SIG. And, at this time, the tone index is [ -28-272728 ].

A. For example, in the case where the same guard tone as 11ac 20MHz is used when performing 20MHz transmission, the NGV data portion may configure a frame as shown in fig. 27, and 20MHz transmission may be performed.

i. As shown in fig. 27, since channel estimation cannot be performed on all available tones by using L-SIG, channel estimation may be performed via interpolation (interpolation) using left and right extra tones of lower and upper 10MHz bands.

B. In addition, the transmitting apparatus may configure a frame as shown in fig. 28, and may perform 20MHz transmission. As shown in fig. 28, in the case where the guard tones (i.e., left guard (e.g., 6 tones) and right guard (e.g., 5 tones)) of the L portion and NGV data portion are the same, an extra tone may be added. At this time, the tone index of the extra tone is [ 27282930 ] in the upper 10MHz band and [ -30-29-28-27] in the lower 10MHz band.

Fig. 28 is only an example, and in case that the number of available tones is different, in order to perform channel estimation according to frequency, additional tones may be added not only to the center tone including DC but also to the tones on both sides.

3. As described above, channel estimation for the NGV data portion may be performed by using extra tones added to the L-SIG.

4. Since the NGV PPDU format of fig. 24 does not additionally configure an NGV-STF for AGC estimation, an NGV-LTF for channel estimation, and a control field, frame overhead can be reduced.

5. Unlike part 4, transmission may be performed by using a frame structure in which L-SIG (RL-SIG) is repeated to achieve robust transmission of 11 bd.

Fig. 29 shows a PPDU format in which RL-SIG is added to the NGV PPDU format of fig. 26.

A. Information on 11p and NGV frame formats may be indicated by using RL-SIG.

i. For example, the information may be indicated by using polarity (polarity) of the RL-SIG.

B. The extra tones may be used in both the L-SIG and RL-SIG, in which case the 4 extra tones may be used in their entirety for channel estimation, or only the 4 extra tones applied to the L-SIG may be used.

i. Information about the NGV data field (e.g., information about BW, coding, format, etc.) may be notified by using the 4 extra tones used in the RL-SIG.

2) When transmission is performed with a 20MHz bandwidth, an NGV frame is configured by duplicating all 10MHz unit frame formats

Fig. 30 shows an example of an NGV PPDU format with a copied L part and NGV part.

Unlike the embodiment of 1), to support interoperability, NGV frames may be configured as shown in fig. 30 when 20MHz bandwidth transmission is performed.

A. When performing wide bandwidth transmission, a frame is configured by duplicating a 10MHz unit frame format within a wide bandwidth.

B.L sections (L-STF, L-LTF and L-SIG) and NGV-SIG/one OFDM symbol may be configured to have a structure copied in units of 10MHz channels, and NGV sections (NGV-STF, NGV-LTF and NGV data) are also configured by being copied in units of 10MHz channels as with the L section.

C. At this time, NGV data transmitted through each 10MHz channel may be loaded by distributing the encoded data to each 10MHz channel, or NGV data transmitted through each 10MHz channel may be loaded by separately performing an encoding process on different data every 10 MHz. In addition, the same data may be repeated and then transmitted.

i. The OFDM symbols for NGV data transmission are configured by using the same carrier spacing as the conventional 11 p.

To improve transmission efficiency, NGV data may be transmitted by using a 40MHz tone plan of 11 ac. In the above structure, the tone spacing of the NGV portion may be configured by using 1/2 of the 11p tone spacing corresponding to 78.125 kHz.

D. In the above structure, in order to achieve reliability enhancement, range expansion, and packet classification, a frame may be configured by placing a symbol (RL-SIG) in which L-SIG is repeated between L-SIG and NGV-SIG.

E. As described above, since a signal is transmitted by using the duplicated frame format of the legacy system, when 20MHz transmission is performed, interoperability can be fully supported since there is no influence on the legacy system.

F. As described above, in the case of performing wide bandwidth transmission by using duplicated frames, in order to transmit a larger amount of data to the NGV device, the NGV portion may configure the frames by allocating additional tones. That is, transmission may be performed by using a tone allocation other than 11p (e.g., a tone allocation of a 20MHz band of 11 ac).

i. The extra tones allocated to the NGV devices are decoded and used only by the NGV devices. Also, the 11p device identifies the extra tone as a guard tone, and thus, the 11p device does not decode the extra tone.

i-1. thus, by using the extra tones, as described above, interoperability with conventional 11p STAs may be maintained and a greater number of tones may be used for NGV devices.

Additional tones for NGV STAs may be added as described below.

The AP configures the frame by adding extra tones only in the NGV portion (i.e., starting from the NGV-STF).

in order to transmit a larger amount of information through the NGV-SIG field, additional tones are applied from the L-SIG field. At this time, the extra tone transmitted through the L-SIG is used in order to perform channel estimation on the extra tone of the NGV field.

At this time, the tone index of the extra tone is [ -28-272728 ]. In the case where the L-SIG is repeated after the L-SIG (RL-SIG), the extra tone is repeated as well.

ii-3. unlike the description provided above, the extra tones may be sent by applying the extra tones from the beginning (or beginning) of the frame. Also, at this time, as in the conventional method, the 11p STA receives a signal by using only the remaining tones except for the extra tone, and when receiving a signal, the NGV STA receives a signal by using all tones including the extra tone.

Fig. 31 shows an example of a PPDU format that does not include NGV-STF in the NGV PPDU format of fig. 30.

Fig. 32 shows an example of a PPDU format that does not include NGV-LTF in the NGV PPDU format of fig. 30.

Fig. 33 shows an example of a PPDU format not including NGV-STF and NGV-LTF in the NGV PPDU format of fig. 30.

FIG. 34 shows an example of a PPDU format that does not include NGV-STF, NGV-LTF, and NGV-SIG in the NGV PPDU format of FIG. 30.

G. Since the duplicated frame format is used to perform 20MHz transmission, a signal can be transmitted by using the frame formats shown in fig. 31 to 34, unlike the description provided above. Hereinafter, the frame formats of fig. 31 to 34 are merely exemplary. Also, although not shown in fig. 31 to 34, in order to perform range expansion and packet classification, L-SIG (RL-SIG) may be repeatedly configured after L-SIG.

i. Frame format not including NGV-STF

i-1. when performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform AGC for 20MHz by using the L-STF. Therefore, in the case where the NGV section uses the same parameter set as the conventional section, AGC estimation does not need to be additionally performed in the NGV section. In addition, even though the NGV part has been configured by using a different set of parameters (e.g., 4x DC), since power control can be performed by using AGC obtained by using a conventional (or existing) L-STF, no additional AGC estimation needs to be performed on the NGV part. Therefore, in this case, it is not necessary to configure the NGV-STF, and therefore, the frame format can be configured as shown in fig. 31.

i-2 since a separate NGV-STF is not configured for AGC estimation, frame overhead can be reduced.

Frame format without NGV-LTF

When performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform channel estimation for 20MHz by using the L-LTF. Therefore, in the case where the NGV section uses the same parameter set as the conventional section, it is not necessary to additionally perform channel estimation in the NGV section. In the case where the NGV portion has been configured by using a different set of parameters (e.g., 4x DC), since the tone spacing is 1/2, the channel estimation value obtained by using the existing L-LTF can be applied to two carriers. And, therefore, there is no need to configure the NGV-LTF to perform additional channel estimation on the NGV portion. Therefore, in this case, it is not necessary to configure the NGV-LTF for channel estimation, and therefore, the frame format may be configured as shown in fig. 32.

Since a separate NGV-LTF is not configured for channel estimation, frame overhead can be reduced.

Frame formats excluding NGV-STF and NGV-LTF

When performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform AGC and channel estimation for 20MHz by using the L-STF and the L-LTF. Therefore, in the case where the NGV section uses the same parameter set as the conventional section, there is no need to additionally perform AGC estimation and channel estimation. In the case where the NGV portion is configured by using a different set of parameters (e.g., 4x DC), then the AGC estimation and channel estimation information obtained by using the existing L-STF and L-LTF can be used by applying to the NGV portion since the tone spacing is 1/2. For example, in the case of configuring NGV data by using 4x DC, since the tone spacing becomes 1/2 of the L part, almost no change occurs in the channel according to the frequency. Accordingly, data can be estimated by applying information on a channel estimated for a carrier by using L-LTF to 2 subcarriers of an NGV data part. As described above, since information estimated by using the L-STF and the L-LTF can be used, it is not necessary to configure NGV-STF and NGV-LTF for AGC estimation and channel estimation. And, therefore, the frame format can be configured as shown in fig. 33.

iii-2 since separate NGV-STF and NGV-LTF are not configured for AGC estimation and channel estimation, frame overhead can be reduced.

iii-3. unlike the description provided above, NGV transmission may be performed by using a structure including RL-SIG for robust transmission or for packet classification.

iii-3-A. an indication may be provided for 11p PPDU and NGV PPDU or NGV frame formats by using RL-SIG.

iii-3-A-i. for example, information can be indicated by using the polarity of RL-SIG.

Additional tones may be used in the L-SIG and RL-SIG. Also, in this case, the 4 extra tones may be all used for channel estimation, or only the 4 extra tones applied to the L-SIG may be used.

information about the NGV data field (e.g., information about BW, coding, format, etc.) may be pre-notified by using the 4 extra tones used in the RL-SIG.

Frame formats that do not include NGV-STF, NGV-LTF, and NGV-SIG fields

1. When performing 20MHz transmission, the L part has been transmitted before the NGV part, and the NGV STA can perform AGC and channel estimation for 20MHz by using the L-STF and the L-LTF.

2. To use a greater number of tones for NGV data transmission, extra tones may be added to the L-SIG and, by using the extra tones, channel estimation may be performed on the additionally used NGV data tones. As described above, since information estimated by using the L-STF, L-LTF, and L-SIG can be used, it is not necessary to configure NGV-STF and NGV-LTF for performing AGC estimation and channel estimation and NGV-SIG for estimating NGV data tones. And, therefore, the frame format can be configured as shown in fig. 34.

3. Unlike the description provided above, NGV transmission may be performed by using a structure including RL-SIG for robust transmission or for packet classification.

A. Indications may be provided for 11p PPDU and NGV PPDU or NGV frame formats by using RL-SIG.

i. For example, the information may be indicated by using the polarity of the RL-SIG.

B. Additional tones may be used in the L-SIG and RL-SIG. Also, in this case, the 4 extra tones may be all used for channel estimation, or only the 4 extra tones applied to the L-SIG may be used.

i. Information about the NGV data field (e.g., information about BW, coding, format, etc.) may be notified by using the 4 extra tones used in the RL-SIG.

v. as described above, in the case of transmitting NGV signals by using a duplicated frame format, data transmitted through respective 10MHz channels in order to increase throughput of NGV data transmission may be different from each other, and NGV data may be transmitted by repeating the same data in order to increase reliability of NGV transmission.

1. Information on the format of data transmitted through the 10MHz channel may be transmitted through the NGV-SIG.

A. To indicate a transmission format of NGV data, the NGV-SIG field may allocate 1 bit for a frame format/transmission mode in order to indicate to the STA whether data is copied and then transmitted as described above, or whether another data is transmitted.

B. In the description provided above, in the NGV-SIG field configured every 10MHz, the same information may be duplicated, or different types of information may be transmitted through a 10MHz channel.

2. If different data is transmitted, the signal may be transmitted by applying a different type of modulation to each 10MHz channel.

3) Structure for transmitting more information from NGV-SIG by using 4 extra tones

To transmit a larger amount of control information in the frame structure proposed in this embodiment, a larger amount of information can be transmitted from the NGV-SIG by using 4 extra tones (where the tone indices for 10MHz are-28, -27, 28).

An ngv-SIG symbol may transmit a signal by using 56 available subcarriers (or tones).

To perform channel estimation on the extra tones, 4 extra tones may also be used in the L-SIG (e.g., tone indices-28, -27, 28). And, in this case, the 4 extra tones will be used for channel estimation only.

To perform channel estimation more accurately, 4 extra tones for channel estimation may also be used in the L-LTF.

Hereinafter, the embodiment of the present disclosure described above with reference to fig. 13 to 34 will be described in more detail.

Fig. 35 is a flowchart showing a procedure of transmitting an NGV frame by the transmitting apparatus according to the present embodiment.

The example of fig. 35 may be performed in a network environment supported by a next generation wireless LAN system. The next generation wireless LAN system is an enhanced version of the 802.11p system that can satisfy backward compatibility with the 802.11p system. The next-generation wireless LAN system may also be referred to as a next-generation V2X (NGV) wireless LAN system or an 802.11bd wireless LAN system.

The example of fig. 35 is performed by a transmitting apparatus, and the transmitting apparatus may correspond to an AP. The receiving apparatus of this embodiment may correspond to an NGV STA supporting an NGV or 802.11bd system, or may correspond to an 11p STA supporting an 802.11p system.

This embodiment proposes a method for configuring an NGV frame for transmitting an NGV signal over a wide frequency band (20MHz or more) while satisfying interoperability, backward compatibility, or coexistence between an NGV or 802.11bd wireless LAN system and an 802.11p system that is a legacy system.

In step S3510, the transmitting device generates a New Generation Vehicle (NGV) frame.

In step S3520, the transmitting apparatus transmits the NGV frame through the first band.

The NGV frame includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG), a Repeated Legacy (RL) -SIG, an NGV-STF, an NGV-LTF, and NGV data.

The L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG are duplicated in units of the second frequency band and transmitted through the first frequency band. The first frequency band is a 20MHz frequency band and the second frequency band is a 10MHz frequency band. That is, the L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG may be configured in units of a 10MHz band (or channel), and in order to transmit in a 20MHz band, frames (legacy portion and NGV-SIG) transmitted in the 10MHz band may be copied once and then transmitted.

In contrast, NGV-STF, NGV-LTF and NGV data are transmitted over the full band of the first band. That is, NGV-STF, NGV-LTF, and NGV data, which are the remaining fields except for the previously copied field, can be transmitted by using all of the entire 20MHz band (first band).

Additionally, the NGV frame may include a legacy portion, an NGV-SIG, and an NGV portion. At this time, the legacy portion may include L-STF, L-LTF, L-SIG, and RL-SIG. The NGV portion may include NGV-STF, NGV-LTF, and NGV data.

The legacy portion and NGV-SIG may be generated by performing 2x Down Conversion (DC) on a frame format for the 20MHz band defined in the 802.11a system.

The NGV portion may be generated by performing 2x Down Conversion (DC) on a frame format for the 40MHz band defined in the 802.11ac system. Alternatively, the NGV portion may be generated without performing DC on a frame format for the 20MHz band defined in the 802.11ac system. Alternatively, the NGV portion may be generated by performing 4x DC on a frame format for the 80MHz band defined in the 802.11ac system.

The NGV portion may have an Orthogonal Frequency Division Multiplexing (OFDM) parameter set having the same symbol length as the legacy portion, or may have an OFDM parameter set having a symbol length 2 times that of the legacy portion. If the NGV portion has the same set of OFDM parameters as the legacy portion in symbol length, the tone spacing of the NGV portion may be equal to 156.26 kHz. And, if the NGV portion has an OFDM parameter set with a symbol length 2 times that of the legacy portion, the tone spacing of the NGV portion may be equal to 78.125 kHz.

AGC estimation information of the NGV portion may be obtained from Automatic Gain Control (AGC) estimation information obtained based on the L-STF. Therefore, the NGV-STF may not be included in the NGV section since an additional AGC estimation process does not need to be performed for the NGV section.

The channel estimation information of the NGV portion may be obtained from the channel estimation information obtained based on the L-LTF. Therefore, the NGV-LTF may not be included in the NGV section since there is no need to perform an additional channel estimation process for the NGV section.

The RL-SIG can be used to extend the signal range and to perform packet classification. In addition, RL-SIG can also be used to enhance the reliability of L-SIG as the signal field of L-SIG is repeated between L-SIG and NGV-SIG.

The packet classification information may be information that classifies the legacy frames and NGV frames. As RL-SIG is transmitted (or as L-SIG is repeated and then transmitted), the range of NGV signals may be expanded.

The RL-SIG or NGV-SIG may be modulated based on quadrature binary phase shift keying (Q-BPSK). By modulating RL-SIG or NGV-SIG based on Q-BPSK, an NGV (or 802.11bd) apparatus can perform packet classification that distinguishes between legacy frames and NGV frames.

Extra tones may be added to the L-SIG and RL-SIG. The extra tones may be used to perform channel estimation for the legacy portion and the NGV portion.

The tone index of the extra tone may be-28, -27, 28. In an 802.11p system, since the OFDM subcarriers range from-26 to 26, the index of the added extra tone may be-28, -27, 28. For example, since L-SIG and RL-SIG are duplicated once in units of 10MHz bands, extra tones may be added for the higher 10MHz band and extra tones may be added for the lower 10MHz band (herein, the tone indices of the extra tones added to each of the higher 10MHz band and the lower 10MHz band are-28, -27, 28). As another example, additional tones with tone indices of 27, 28, 29, 30 may be added for the higher 10MHz band, and additional tones with tone indices of-30, -29, -28, -27 may be added for the lower 10MHz tone.

The reception apparatus may include a legacy STA supporting the 802.11p system or an NGV STA supporting the 802.11bd system.

In the case where the receiving apparatus is a legacy STA supporting the 802.11p system, the receiving apparatus (legacy STA) may decode even the legacy portion, and by decoding the RL-SIG, the receiving apparatus may verify that the corresponding frame is not its frame (or PPDU) and may stop the decoding process.

In the case where the reception apparatus is an NGV STA supporting the 802.11bd system, the reception apparatus can decode the legacy portion and the NGV-SIG in order to know control information required for the NGV portion, and then, the reception apparatus can receive an NGV frame through a 20MHz band.

In addition, the NGV-SIG may also include information about Modulation and Coding Scheme (MCS), number of space-time streams (NSTS), transmit opportunity (TXOP), Dual Carrier Modulation (DCM), midamble, doppler, space-time block coding (STBC), coding, bandwidth, Basic Service Set (BSS) color, BSS identifier, reception identifier, packet length, signal range, Low Density Parity Check (LDPC) additional (or extra) symbols, Cyclic Redundancy Check (CRC), and tail bits.

The information on the bandwidth may include information on a 10MHz or 20MHz band supported by the wireless LAN system. The information on the MCS may include information that the wireless LAN system supports at most 256 QAM. The information on encoding may include information on Binary Convolutional Codes (BCC) or LDPC supported by the wireless LAN system.

Fig. 36 is a flowchart showing a procedure of receiving an NGV frame by a receiving device according to the present embodiment.

The example of fig. 36 can be performed in a network environment supported by a next generation wireless LAN system. The next generation wireless LAN system is an enhanced version of the 802.11p system that can satisfy backward compatibility with the 802.11p system. The next-generation wireless LAN system may also be referred to as a next-generation V2X (NGV) wireless LAN system or an 802.11bd wireless LAN system.

The example of fig. 36 is performed by a reception apparatus, and the reception apparatus may correspond to an NGV STA supporting an NGV or 802.11bd system, or may correspond to an 11p STA supporting an 802.11p wireless LAN system. The transmission apparatus of fig. 36 may correspond to an AP.

This embodiment proposes a method for configuring an NGV frame for transmitting an NGV signal over a wide frequency band (20MHz or more) while satisfying interoperability, backward compatibility, or coexistence between an NGV or 802.11bd wireless LAN system and an 802.11p system that is a legacy system.

In step S3610, the receiving device receives a New Generation Vehicle (NGV) frame from the transmitting device through the first frequency band.

In step S3620, the receiving apparatus decodes the received NGV frame.

The NGV frame includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG), a Repeated Legacy (RL) -SIG, an NGV-STF, an NGV-LTF, and NGV data.

The L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG are copied in units of the second frequency band and transmitted through the first frequency band. The first frequency band is a 20MHz frequency band and the second frequency band is a 10MHz frequency band. That is, the L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG may be configured in units of a 10MHz band (or channel), and, in order to be transmitted in a 20MHz band, frames (legacy portion and NGV-SIG) transmitted in the 10MHz band may be copied once and then transmitted.

In contrast, NGV-STF, NGV-LTF and NGV data are transmitted over the full band of the first band. That is, NGV-STF, NGV-LTF, and NGV data, which are the remaining fields except for the previously copied field, can be transmitted by using all of the entire 20MHz band (first band).

Additionally, the NGV frame may include a legacy portion, an NGV-SIG, and an NGV portion. At this time, the legacy portion may include L-STF, L-LTF, L-SIG, and RL-SIG. The NGV portion may include NGV-STF, NGV-LTF, and NGV data.

The legacy portion and NGV-SIG may be generated by performing 2x Down Conversion (DC) on a frame format for the 20MHz band defined in the 802.11a system.

The NGV portion may be generated by performing 2x Down Conversion (DC) on a frame format for the 40MHz band defined in the 802.11ac system. Alternatively, the NGV portion may be generated without performing DC for a frame format for a 20MHz band defined in an 802.11ac system. Alternatively, the NGV portion may be generated by performing 4x DC on a frame format for the 80MHz band defined in the 802.11ac system.

The NGV portion may have an Orthogonal Frequency Division Multiplexing (OFDM) parameter set having the same symbol length as the legacy portion, or may have an OFDM parameter set having a symbol length 2 times that of the legacy portion. If the NGV portion has OFDM parameters with the same symbol length as the legacy portion, the tone spacing of the NGV portion may be equal to 156.26 kHz. And, if the NGV portion has an OFDM parameter set with a symbol length 2 times that of the legacy portion, the tone spacing of the NGV portion may be equal to 78.125 kHz.

AGC estimation information of the NGV portion may be obtained from Automatic Gain Control (AGC) estimation information obtained based on the L-STF. Therefore, the NGV-STF may not be included in the NGV section since an additional AGC estimation process does not need to be performed for the NGV section.

The channel estimation information of the NGV portion may be obtained from the channel estimation information obtained based on the L-LTF. Therefore, the NGV-LTF may not be included in the NGV section since there is no need to perform an additional channel estimation process for the NGV section.

The RL-SIG can be used to extend the signal range and to perform packet classification. In addition, RL-SIG can also be used to enhance the reliability of L-SIG as the signal field of L-SIG is repeated between L-SIG and NGV-SIG.

The packet classification information may be information that classifies the legacy frames and NGV frames. As RL-SIG is transmitted (or as L-SIG is repeated and then transmitted), the range of NGV signals may be expanded.

The RL-SIG or NGV-SIG may be modulated based on quadrature binary phase shift keying (Q-BPSK). By modulating RL-SIG or NGV-SIG based on Q-BPSK, an NGV (or 802.11bd) apparatus can perform packet classification that distinguishes between legacy frames and NGV frames.

Extra tones may be added to the L-SIG and RL-SIG. The extra tones may be used to perform channel estimation for the legacy portion and the NGV portion.

The tone index of the extra tone may be-28, -27, 28. In an 802.11p system, since the OFDM subcarriers range from-26 to 26, the index of the additional tones added may be-28, -27, 28. For example, since L-SIG and RL-SIG are duplicated once in units of 10MHz bands, extra tones may be added for the higher 10MHz band and extra tones may be added for the lower 10MHz band (herein, the tone indices of the extra tones added to each of the higher 10MHz band and the lower 10MHz band are-28, -27, 28). As another example, additional tones with tone indices of 27, 28, 29, 30 may be added for the higher 10MHz band, and additional tones with tone indices of-30, -29, -28, -27 may be added for the lower 10MHz band.

The reception apparatus may include a legacy STA supporting the 802.11p system or an NGV STA supporting the 802.11bd system.

In the case where the receiving apparatus is a legacy STA supporting the 802.11p system, the receiving apparatus (legacy STA) may decode even the legacy portion, and by decoding the RL-SIG, the receiving apparatus may verify that the corresponding frame is not its frame (or PPDU) and may stop the decoding process.

In the case where the reception apparatus is an NGV STA supporting the 802.11bd system, the reception apparatus can decode the legacy portion and the NGV-SIG in order to know control information required for the NGV portion, and then, the reception apparatus can receive an NGV frame through a 20MHz band.

In addition, the NGV-SIG may also include information about Modulation and Coding Scheme (MCS), number of space-time streams (NSTS), transmit opportunity (TXOP), Dual Carrier Modulation (DCM), midamble, doppler, space-time block coding (STBC), coding, bandwidth, Basic Service Set (BSS) color, BSS identifier, reception identifier, packet length, signal range, Low Density Parity Check (LDPC) additional (or extra) symbols, Cyclic Redundancy Check (CRC), and tail bits.

The information on the bandwidth may include information on a 10MHz or 20MHz band supported by the wireless LAN system. The information on the MCS may include information that the wireless LAN system supports at most 256 QAM. The information on encoding may include information on Binary Convolutional Codes (BCC) or LDPC supported by the wireless LAN system.

7. Device arrangement

Fig. 37 is a diagram for describing an apparatus for implementing the above-described method.

The wireless device (100) of fig. 37 is a transmission device that can implement the above-described embodiments and can operate as an AP STA. The wireless device (150) of fig. 37 is a receiving device that can implement the above-described embodiments and can operate as a non-AP STA.

The transmitting apparatus (100) may include a processor (110), a memory (120), and a transmitting/receiving unit (130), and the receiving apparatus (150) may include a processor (160), a memory (170), and a transmitting/receiving unit (180). The transmission/reception unit (130, 180) transmits/receives radio signals, and can operate in the physical layer of IEEE 802.11/3GPP or the like. The processor (110, 160) may operate in a physical layer and/or a MAC layer and may be operatively connected to the transmitting/receiving unit (130, 180).

The processor (110, 160) and/or the transmit/receive unit (130, 180) may include an Application Specific Integrated Circuit (ASIC), other chipsets, logic circuitry, and/or a data processor. The memory (120, 170) may include Read Only Memory (ROM), Random Access Memory (RAM), flash memory, memory cards, storage media, and/or other storage units. When the embodiments are performed by software, the techniques (or methods) described herein may be performed with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules may be stored in a memory (120, 170) and executed by a processor (110, 160). The memory (120, 170) may be implemented (or placed) within the processor (110, 160) or external to the processor (110, 160). Further, the memory (120, 170) may be operatively connected to the processor (110, 160) via various means known in the art.

The processor (110, 160) may implement the functions, processes, and/or methods set forth in this disclosure. For example, the processor (110, 160) may perform operations according to the present embodiments.

The operation of the processor (110) of the transmitting apparatus will be described in detail as follows. A processor (110) of the transmitting device generates an NGV frame and transmits the NGV frame through the first band.

The operation of the processor (160) of the receiving apparatus will be described in detail as follows. A processor (160) of the receiving device receives the NGV frames from the transmitting device through the first frequency band and decodes the received NGV frames.

Fig. 38 illustrates a UE to which technical features of the present disclosure may be applied.

The UE includes a processor (610), a power management module (611), a battery (612), a display (613), a keypad (614), a Subscriber Identity Module (SIM) card (615), a memory (620), a transceiver (630), one or more antennas (631), a speaker (640), and a microphone (641).

The processor (610) may be configured to implement the functions, processes, and/or methods set forth in the present disclosure described below. The processor (610) may be configured to control one or more other components of the UE (600) to implement the functions, processes, and/or methods set forth by the present disclosure as described below. Layers of a radio interface protocol may be implemented in the processor (610). The processor (610) may include an Application Specific Integrated Circuit (ASIC), other chipsets, logic circuitry, and/or data processing means. The processor (610) may be an Application Processor (AP). The processor (610) may include at least one of a Digital Signal Processor (DSP), a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a modem (modulator and demodulator). An example of the processor (610) may be implemented byManufactured SNAPDRAGONTM series processors,Manufactured EXYNOST series processor,A series of processors manufactured,A manufactured HELIOTM series of processors,Manufactured ATOM family of processors or corresponding next generation processors.

The power management module (611) manages power for the processor (610) and/or the transceiver (630). The battery (612) supplies power to the power management module (611). The display (613) outputs the results of the processing by the processor (610). The keypad (614) receives input to be used by the processor (610). The keypad (614) may be displayed on the display (613). The SIM card (615) is an integrated circuit used to securely store an International Mobile Subscriber Identity (IMSI) number and its associated keys for identifying and authenticating users on mobile telephone devices, such as mobile telephones and computers. The contact information may also be stored on a number of SIM cards.

The memory (620) is operatively coupled with the processor (610) and stores various information to operate the processor (610). The memory (620) may include Read Only Memory (ROM), Random Access Memory (RAM), flash memory, memory cards, storage media, and/or other storage devices. When the embodiments are implemented in software, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules may be stored in a memory (620) and executed by a processor (610). The memory (620) may be implemented within the processor (610) or external to the processor (610), in which case the memory (620) may be communicatively coupled to the processor (610) via various means as is known in the art.

The transceiver 630 is operatively coupled with the processor 610 and transmits and/or receives radio signals. The transceiver (630) includes a transmitter and a receiver. The transceiver (630) may include baseband circuitry for processing radio frequency signals. The transceiver (630) controls one or more antennas (631) to transmit and/or receive radio signals.

The speaker (640) outputs sound-related results processed by the processor (610). The microphone (641) receives sound-related input to be used by the processor (610).

In the case of a transmitting device, a processor (610) generates an NGV frame and transmits the NGV frame through a first band.

In the case of a receiving device, a processor (610) receives NGV frames from a transmitting device over a first frequency band and decodes the received NGV frames.

The NGV frame includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG), a Repeated Legacy (RL) -SIG, an NGV-STF, an NGV-LTF, and NGV data.

The L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG are copied in units of the second frequency band and transmitted through the first frequency band. The first frequency band is a 20MHz frequency band and the second frequency band is a 10MHz frequency band. That is, the L-STF, L-LTF, L-SIG, RL-SIG, and NGV-SIG may be configured in units of a 10MHz band (or channel), and, in order to be transmitted in a 20MHz band, frames (legacy portion and NGV-SIG) transmitted in the 10MHz band may be copied once and then transmitted.

In contrast, NGV-STF, NGV-LTF and NGV data are transmitted over the full band of the first band. That is, NGV-STF, NGV-LTF, and NGV data, which are the remaining fields except for the previously copied field, can be transmitted by using all of the entire 20MHz band (first band).

Additionally, the NGV frame may include a legacy portion, an NGV-SIG, and an NGV portion. At this time, the legacy portion may include L-STF, L-LTF, L-SIG, and RL-SIG. The NGV portion may include NGV-STF, NGV-LTF, and NGV data.

The legacy portion and NGV-SIG may be generated by performing 2x Down Conversion (DC) on a frame format for the 20MHz band defined in the 802.11a system.

The NGV portion may be generated by performing 2x Down Conversion (DC) on a frame format for the 40MHz band defined in the 802.11ac system. Alternatively, the NGV portion may be generated without performing DC for a frame format for a 20MHz band defined in an 802.11ac system. Alternatively, the NGV portion may be generated by performing 4x DC on a frame format for the 80MHz band defined in the 802.11ac system.

The NGV portion may have an Orthogonal Frequency Division Multiplexing (OFDM) parameter set having the same symbol length as the legacy portion, or may have an OFDM parameter set having a symbol length 2 times that of the legacy portion. If the NGV portion has the same set of OFDM parameters as the legacy portion in symbol length, the tone spacing of the NGV portion may be equal to 156.26 kHz. And, if the NGV portion has an OFDM parameter set with a symbol length 2 times that of the legacy portion, the tone spacing of the NGV portion may be equal to 78.125 kHz.

AGC estimation information of the NGV portion may be obtained from Automatic Gain Control (AGC) estimation information obtained based on the L-STF. Therefore, the NGV-STF may not be included in the NGV section since an additional AGC estimation process does not need to be performed for the NGV section.

The channel estimation information of the NGV portion may be obtained from the channel estimation information obtained based on the L-LTF. Therefore, the NGV-LTF may not be included in the NGV section since there is no need to perform an additional channel estimation process for the NGV section.

The RL-SIG can be used to extend the signal range and to perform packet classification. In addition, RL-SIG can also be used to enhance the reliability of L-SIG as the signal field of L-SIG is repeated between L-SIG and NGV-SIG.

The packet classification information may be information that classifies the legacy frames and NGV frames. As RL-SIG is transmitted (or as L-SIG is repeated and then transmitted), the range of NGV signals may be expanded.

The RL-SIG or NGV-SIG may be modulated based on quadrature binary phase shift keying (Q-BPSK). By modulating RL-SIG or NGV-SIG based on Q-BPSK, an NGV (or 802.11bd) apparatus can perform packet classification that distinguishes between legacy frames and NGV frames.

Extra tones may be added to the L-SIG and RL-SIG. The extra tones may be used to perform channel estimation for the legacy portion and the NGV portion.

The tone index of the extra tone may be-28, -27, 28. In an 802.11p system, since the OFDM subcarriers range from-26 to 26, the index of the added extra tone may be-28, -27, 28. For example, since L-SIG and RL-SIG are duplicated once in units of 10MHz bands, extra tones may be added for the higher 10MHz band and extra tones may be added for the lower 10MHz band (herein, the tone indices of the extra tones added to each of the higher 10MHz band and the lower 10MHz band are-28, -27, 28). As another example, additional tones with tone indices of 27, 28, 29, 30 may be added for the higher 10MHz band, and additional tones with tone indices of-30, -29, -28, -27 may be added for the lower 10MHz tone.

The reception apparatus may include a legacy STA supporting the 802.11p system or an NGV STA supporting the 802.11bd system.

In the case where the receiving apparatus is a legacy STA supporting the 802.11p system, the receiving apparatus (legacy STA) may decode even the legacy portion, and by decoding the RL-SIG, the receiving apparatus may verify that the corresponding frame is not its frame (or PPDU) and may stop the decoding process.

In the case where the reception apparatus is an NGV STA supporting the 802.11bd system, the reception apparatus can decode the legacy portion and the NGV-SIG in order to know control information required for the NGV portion, and then, the reception apparatus can receive an NGV frame through a 20MHz band.

In addition, the NGV-SIG may also include information about Modulation and Coding Scheme (MCS), number of space-time streams (NSTS), transmit opportunity (TXOP), Dual Carrier Modulation (DCM), midamble, doppler, space-time block coding (STBC), coding, bandwidth, Basic Service Set (BSS) color, BSS identifier, reception identifier, packet length, signal range, Low Density Parity Check (LDPC) additional (or extra) symbols, Cyclic Redundancy Check (CRC), and tail bits.

The information on the bandwidth may include information on a 10MHz or 20MHz band supported by the wireless LAN system. The information on the MCS may include information that the wireless LAN system supports at most 256 QAM. The information on encoding may include information on Binary Convolutional Codes (BCC) or LDPC supported by the wireless LAN system.