阅读说明：本技术 通信设备及通信方法、信息处理设备、其控制方法和程序 (Communication apparatus, communication method, information processing apparatus, control method therefor, and program ) 是由 藤森祐树 于 2020-02-05 设计创作，主要内容包括：通信设备发送无线帧,该无线帧具有物理层(PHY)的前导码和数据字段。前导码包括传统短训练字段(L-STF)、传统长训练字段(L-LTF)、传统信号字段(L-SIG)、极高吞吐量信号A字段(EHT-SIG-A)、EHT短训练字段(EHT-STF)和EHT长训练字段(EHT-LTF)。EHT-SIG-A包括子字段,在该子字段中,与在数据字段中包括的数据的发送中是否使用混合自动重传请求(HARQ)有关的信息被设置。(A communication device transmits a radio frame having a preamble and a data field of a physical layer (PHY). The preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a very high throughput signal A field (EHT-SIG-A), an EHT short training field (EHT-STF), and an EHT long training field (EHT-LTF). The EHT-SIG-a includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in the data field is set.)

1. A communication device, the communication device comprising:

a transmitting part for transmitting a radio frame including a preamble of a physical layer (PHY) and a data field,

wherein the preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), an extremely high throughput signal A field (EHT-SIG-A), an EHT short training field (EHT-STF), and an EHT long training field (EHT-LTF), and

the EHT-SIG-a includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in a data field is set.

2. The communication device of claim 1, wherein

In the case where the radio frame is used for multi-user communication, another field (EHT-SIG-B) arranged after the EHT-SIG-A and before the EHT-STF is included, and

the EHT-SIG-B includes a subfield in which information on whether HARQ is used in transmission of data included in the data field for each of the plurality of partner devices is set.

3. The communication device according to claim 1 or 2, wherein the subfield includes information of a type of HARQ to be used in case HARQ is used in transmission of data included in the data field.

4. The communication device according to claim 1 or 2, wherein the subfield is a 1-bit field indicating whether HARQ is used in transmission of data included in the data field.

5. The communication device according to any of claims 1 to 4, wherein in case of receiving a radio frame in which information indicating that HARQ is used is set in a subfield, a function for performing reception using HARQ is activated.

6. The communication device according to any one of claims 1 to 5, further comprising a plurality of communication processing sections,

wherein, in a case where a radio frame in which the information indicating that the HARQ is used is set in the subfield is received, the radio frame is distributed to a first communication section among the plurality of communication processing sections, and in a case where a radio frame in which the information indicating that the HARQ is not used is set in the subfield is received, the radio frame is distributed to a second communication section among the plurality of communication processing sections.

7. A communication device, the communication device comprising:

a receiving part for receiving a radio frame including a preamble of a physical layer (PHY) and a data field,

wherein the preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), an extremely high throughput signal A field (EHT-SIG-A), an EHT short training field (EHT-STF), and an EHT long training field (EHT-LTF), and

the EHT-SIG-a includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in the data field is set.

8. An information processing apparatus, the information processing apparatus comprising:

a generation section for generating a radio frame including a preamble and a data field of a physical layer (PHY),

wherein the preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), an extremely high throughput signal A field (EHT-SIG-A), an EHT short training field (EHT-STF), and an EHT long training field (EHT-LTF), and

the EHT-SIG-a includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in the data field is set.

9. A communication method performed by a communication device, the communication method comprising:

a transmitting step of transmitting a radio frame including a preamble and a data field of a physical layer (PHY),

wherein the preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), an extremely high throughput signal A field (EHT-SIG-A), an EHT short training field (EHT-STF), and an EHT long training field (EHT-LTF), and

the EHT-SIG-a includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in the data field is set.

10. A communication method performed by a communication device, the communication method comprising:

a receiving step of receiving a radio frame including a preamble and a data field of a physical layer (PHY),

wherein the preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), an extremely high throughput signal A field (EHT-SIG-A), an EHT short training field (EHT-STF), and an EHT long training field (EHT-LTF), and

the EHT-SIG-a includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in the data field is set.

11. A control method executed by an information processing apparatus, the control method comprising:

a generating step of generating a radio frame including a preamble and a data field of a physical layer (PHY),

wherein the preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), an extremely high throughput signal A field (EHT-SIG-A), an EHT short training field (EHT-STF), and an EHT long training field (EHT-LTF), and

the EHT-SIG-a includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in the data field is set.

12. A program configured to cause a computer to function as one of the communication apparatus defined in any one of claims 1 to 7 and the information processing apparatus defined in claim 8.

Technical Field

The present invention relates to a communication apparatus and a communication method thereof, an information processing apparatus, a control method thereof, and a program, and more particularly, to a communication control technique in a wireless LAN.

Background

In recent years, with an increase in the amount of data to be communicated, communication technologies such as wireless LAN (local area network) have been developed. As a main communication standard of the wireless LAN, IEEE (institute of electrical and electronics engineers) 802.11 standard series is known. The IEEE802.11 family of standards includes standards such as IEEE802.11 a/b/g/n/ac/ax. For example, in the latest standard ieee802.11ax, a technique of achieving a high peak throughput up to 9.6 gigabits per second (Gbps) using OFDMA (orthogonal frequency division multiple access) and further improving the communication speed in case of congestion has been standardized (see patent document 1).

On the other hand, in order to further improve the throughput, a research group called IEEE802.11EHT (very high throughput) has been formed as a successor standard to ieee802.11ax. In EHT, application of HARQ (Hybrid Automatic Repeat reQuest) having a soft combining technique between an Access Point (AP) and a Station (STA) has been examined. When HARQ with soft combining is used, efficient data transmission becomes possible as compared with the case of using conventional ARQ (automatic repeat request).

Reference list

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-050133

Disclosure of Invention

Technical problem

It is useful for a communication apparatus that has received a radio frame to quickly confirm whether HARQ is used in data transmission of the radio frame. On the other hand, since HARQ is not used in the conventional standard, there is no mechanism configured to cause the communication apparatus to recognize whether or not HARQ is used in data transmission of a radio frame.

Means for solving the problems

The present invention provides a technique that allows a communication apparatus to quickly recognize whether HARQ is used in data transmission of a radio frame when the communication apparatus receives the radio frame.

According to an aspect of the present invention, there is provided a communication apparatus characterized by comprising: a transmission section for transmitting a radio frame including a preamble of a physical layer (PHY) and a data field, wherein the preamble includes an L-STF (legacy short training field), an L-LTF (legacy long training field), an L-SIG (legacy signal field), an EHT-SIG-A (very high throughput Signal A field), an EHT-STF (EHT short training field), and an EHT-LTF (EHT long training field), and the EHT-SIG-A includes a subfield in which information on whether hybrid automatic repeat request (HARQ) is used in transmission of data included in the data field is set.

Advantageous effects of the invention

According to the present invention, when a communication apparatus receives a radio frame, it can be quickly identified whether or not HARQ is used in data transmission of the radio frame.

Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings. Note that the same reference numerals are used throughout the drawings to designate the same or similar components.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a diagram showing an example of the configuration of a network;

fig. 2 is a block diagram showing an example of a functional configuration of a communication apparatus;

fig. 3 is a block diagram showing an example of a hardware configuration of a communication apparatus;

fig. 4 is a flowchart showing an example of a procedure of a radio frame transmission process;

fig. 5 is a flowchart showing an example of a procedure of a radio frame reception process;

fig. 6 is a diagram showing an example of a PHY frame structure of an EHT SU PPDU;

fig. 7 is a diagram showing an example of a PHY frame structure of an EHT ER PPDU; and

fig. 8 is a diagram showing an example of a PHY frame structure of an EHT MU PPDU.

Detailed Description

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following examples are not intended to limit the scope of the claimed invention. A plurality of features are described in the embodiments, but the invention is not limited to the invention requiring all of these features, and a plurality of such features may be combined as appropriate. Further, in the drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.

(network construction)

Fig. 1 shows an example of the configuration of a wireless communication network according to the present embodiment. The wireless communication network includes one Access Point (AP) and Three Stations (STAs). Here, the AP 102 and each of the STAs 103 to 105 conforms to IEEE802.11EHT (extremely high throughput), and is configured to be capable of wireless communication conforming to a standard defined before the IEEE802.11EHT standard. Note that the name "IEEE802.11EHT" is provided for convenience and may be other names when the standard is established, but this specification and the appended claims cover all standards capable of supporting the later described processes. In the following description, without reference to a specific device or the like, an access point may be referred to as an "AP" and a station (terminal) may be referred to as an "STA", without reference numerals. Note that in fig. 1, a wireless communication network including one AP and three STAs is shown as an example, but the number of these communication devices may be more or less than the number shown. In an example, when STAs communicate with each other, there may be no AP. In fig. 1, a communicable area of a network formed by an AP 102 is represented by a circle 101. Note that the communication-capable area may cover a larger area, or may cover only a smaller area. Note that EHT is understood to be an acronym for very high throughput.

(construction of the apparatus)

Fig. 2 shows an example of a hardware configuration of each communication device (AP and STA). As an example of its hardware configuration, the communication apparatus includes a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207.

The storage unit 201 is formed of both or one of ROM and RAM, and stores programs for performing various operations described later and various information such as communication parameters for wireless communication. Note that a storage medium such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, or a DVD may be used as the storage unit 201, in addition to the memory such as the ROM and the RAM.

For example, the control unit 202 is formed of, for example, one or more processors such as a CPU and an MPU, an ASIC (application specific integrated circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), or the like. Here, the CPU is an acronym of a Central Processing Unit (Central Processing Unit), and the MPU is an acronym of a Micro Processing Unit (Micro Processing Unit). The control unit 202 executes a program stored in the storage unit 201, thereby controlling the entire apparatus. Note that the control unit 202 can control the entire apparatus by cooperation of a program stored in the storage unit 201 and an OS (operating system).

In addition, the control unit 202 controls the function unit 203 to execute predetermined processing such as image capturing, printing, or projection. The functional unit 203 is hardware used by the apparatus to execute predetermined processing. For example, if the apparatus is a camera, the function unit 203 is an image pickup unit and performs image pickup processing. For example, if the apparatus is a printer, the functional unit 203 is a printing unit and performs print processing. For example, if the apparatus is a projector, the function unit 203 is a projection unit and performs projection processing. The data to be processed by the function unit 203 may be data stored in the storage unit 201, or may be data that communicates with other APs or STAs via the communication unit 206 described below.

The input unit 204 receives various operations from a user. The output unit 205 performs various outputs to the user. Here, the output of the output unit 205 includes, for example, at least one of display on a screen, audio output of a speaker, vibration output, and the like. Note that both the input unit 204 and the output unit 205 can be implemented by one module like a touch panel.

The communication unit 206 controls wireless communication conforming to the IEEE802.11 standard series, or controls IP communication. The communication unit 306 is a so-called radio chip and may itself comprise one or more processors and memory. In the present embodiment, the communication unit 206 may perform processing conforming to at least the ieee802.11ax standard. In addition, the communication unit 206 controls the antenna 207 to transmit and receive a radio signal for wireless communication. The device communicates content such as image data, document data, or video data with other communication devices via the communication unit 306. The antenna 207 is an antenna that can transmit and receive a signal in at least any one of, for example, a sub-GHz band, a 2.4GHz band, a 5GHz band, and a 6GHz band. Note that the frequency band (and combination of frequency bands) to which the antenna 207 can adapt is not particularly limited. The antenna 207 may be one antenna, or may be a group of two or more antennas for MIMO (multiple input and multiple output) transmission/reception. Fig. 2 shows one antenna 207, but the antenna may comprise two or more antennas (two or more sets of antennas) adapted for different frequency bands.

Fig. 3 shows an example of a functional configuration of each communication device (AP and STA). As an example, the communication apparatus includes a wireless LAN control unit 301, a frame generation unit 302, an HARQ control unit 303, a UI control unit 304, a storage unit 305, and an antenna 306.

The wireless LAN control unit 301 is configured to include circuits that transmit/receive radio signals to/from another wireless LAN device (for example, another AP or STA) using the antenna 306, and a program configured to control these circuits. The wireless LAN control unit 301 performs communication control of the wireless LAN such as transmission of the frame generated by the frame generation unit 302 and reception of radio frames from other wireless LAN devices according to the IEEE802.11 standard series. The frame generation unit 302 generates a radio frame including data to be transmitted to, for example, other APs or STAs. At this time, the frame generation unit 302 generates a radio frame based on the control of the HARQ control unit 303. HARQ control section 303 generates an error correction code for transmitting data, controls the version of the error correction code to be transmitted when retransmission is performed, and the like, according to the type of HARQ (hybrid automatic repeat request) to be used. Further, the HARQ control unit 303 performs error correction decoding by an error correction code for the received data according to the type of HARQ to be used. Further, if an error contained in the received data cannot be completely corrected, the HARQ control unit 303 stores the data containing the error in a reception buffer held by the HARQ control unit 303. Then, the HARQ control unit 303 performs error correction decoding using the reception data contained in the packet retransmitted thereafter and the reception data stored in the reception buffer, thereby efficiently performing error correction. Types of HARQ include, for example, Chase Combining (Chase Combining) and incremental redundancy. The type of HARQ may also include, for example, Partial Chase Combining (Partial Chase Combining) and Partial Incremental Redundancy (Partial Incremental Redundancy), etc. These are merely examples, and other HARQ types may be used. The UI control unit 304 is configured to include hardware related to a User Interface (UI), such as a touch panel and buttons configured to accept operations of the communication apparatus by a user (not shown) of the communication apparatus, and a program configured to control these. Note that the UI control unit 304 also has a function of presenting information to the user, such as display of images or audio output, for example. The storage unit 305 is configured to include a storage device such as a ROM (read only memory) or a RAM (random access memory) configured to store a program to be executed by the communication device and various data.

In the present embodiment, if the communication apparatus is a transmission apparatus and transmission data is transmitted using HARQ, the frame generation unit 302 generates a radio frame including a PHY (physical layer) preamble indicating that HARQ is used. If the communication device is a receiving device, the communication device decodes the PHY preamble upon receiving the radio frame, thereby specifying whether to use HARQ. Therefore, for example, the communication apparatus can activate the HARQ control unit 303 according to reception of a radio frame using HARQ, and as a result, waste of power consumption of the communication apparatus can be suppressed. Further, for example, in a communication apparatus including a plurality of communication processing units configured to simultaneously process data, a series of data transmitted using HARQ may be distributed to a first communication processing unit, and data transmitted without using HARQ may be distributed to a second communication processing unit. At this time, when the decoding of the physical header is completed, the data distribution destination can be quickly distributed. Therefore, the simultaneous processing of data can be efficiently performed.

(procedure of treatment)

Next, a procedure of processing to be performed by the communication apparatus will be described. Note that before the processing to be described below is performed, a connection is established between a communication device of a transmission side (hereinafter referred to as a transmission device) and a communication device of a reception side (hereinafter referred to as a reception device) by the processing defined by the IEEE802.11 standard. Also, in order to simplify the description, a process according to whether HARQ is used will be described herein, and a description of ARQ that may be used independently of HARQ will be omitted. Fig. 4 shows an example of a procedure of processing to be performed by the transmitting device, and fig. 5 shows an example of a procedure of processing to be performed by the receiving device.

Based on the completion of the preparation of the transmission target data, the transmission apparatus starts the processing shown in fig. 4 and encodes the transmission target data (step S401). Here, encoding using both an error detection code and an error correction code is performed on transmission target data. As an example, the error detection code may be a Cyclic Redundancy Check (CRC) code, but is not limited thereto. As an example, the error correction code may be a binary convolutional code, a low density parity check code, a turbo code, or the like, but is not limited thereto. Note that an error correction code suitable for both the transmitting apparatus and the receiving apparatus is used.

Then, the transmission apparatus performs processing of generating a radio frame containing the encoded transmission target data. At this time, the transmitting apparatus determines whether to use HARQ (step S402). Upon determining that HARQ is not used (no in step S402), the transmission apparatus generates and transmits a radio frame including a PHY preamble indicating that HARQ is not used (step S403). At this time, if ARQ is not used, the transmitting apparatus discards the transmission target data (step S408). Note that if ARQ is performed, the transmission target data is not discarded but held (for example, in the storage unit 305) to prepare for retransmission and discarded after the processing of steps S405 to S407 described later.

On the other hand, when it is determined that HARQ is used (yes in step S402), the transmitting apparatus generates and transmits a radio frame including a PHY preamble indicating that HARQ is used (step S404). At this time, the transmitting apparatus holds the transmission target data (for example, in the storage unit 305) without discarding, to prepare for retransmission. Then, the transmitting apparatus determines whether the data transmission is successful (step S405). The transmitting device determines that data transmission has been successful if an Ack is received from the receiving device within, for example, a predetermined time (Ack timeout (AckTimeout) defined by the IEEE802.11 standard). Upon determining that the data transmission has succeeded (yes in step S405), the transmission apparatus discards the held transmission target data after the transmission (step S408). Note that at this time, the transmitting apparatus resets the retransmission count to 0. The transmitting device may determine whether the data transmission is successful by, for example, block ACK. In this case, the transmitting device can confirm whether transmission of the transmission target data is successful using a Block ACK Starting Sequence Control (Block ACK Starting Sequence Control) and a Block ACK Bitmap (Block ACK Bitmap) included in the Block ACK. Note that, if the above ACK or block ACK is not received within a predetermined time, the transmitting apparatus determines that data transmission has failed.

Upon determining that the data transmission has failed (no in step S405), next, the transmitting apparatus determines whether the current retransmission count has reached the upper limit value (dot 11ShortRetryLimit defined by the IEEE802.11 standard) (step S406). Note that the current retransmission count is held for each transmission target data, and the initial value is set to 0, incremented by only 1 each time data retransmission is performed. When determining that the retransmission count of the transmission target data has not reached the upper limit value (no in step S406), the transmission apparatus retransmits the transmission target data (step S407). Note that in the retransmission, an appropriate version of the encoded data generated in step S401 is transmitted. For example, in Chase combining type HARQ, the same transmission target data is transmitted every time. In the incremental redundancy type, different versions of encoded data are transmitted at a time. After that, the transmitting apparatus returns the process to step S405 to repeat the retransmission of the transmission target data as necessary. Note that if the retransmission count has reached the upper limit value (yes in step S406), the transmitting apparatus discards the transmission target data (step S408) and ends the processing.

Upon receiving a radio frame (data) from a transmitting apparatus (step S501), the receiving apparatus performs a data decoding process on the received data (step S502). Note that the receiving device decodes the PHY preamble of the radio frame to determine whether the radio frame is suitable for HARQ. Upon receiving the radio frame indicating the use of HARQ, the receiving apparatus starts performing processing from step S503. On the other hand, upon receiving a radio frame indicating that HARQ is not used, the receiving apparatus may request retransmission such as ARQ according to detection of an error in the radio frame, and discard the received radio frame. The receiving apparatus performs decoding processing using a decoding algorithm corresponding to the error correction code, and performs error detection using a detection algorithm corresponding to the error detection code. Note that, for retransmission data in the case of using HARQ, the receiving apparatus performs a decoding process based on (for example, by combining) data including an error and held in the reception buffer and newly received data. This makes it possible to efficiently perform error correction processing.

The receiving apparatus determines whether an error is detected in the result of decoding the received data (step S503). If an error is detected (YES in step S503), the receiving apparatus determines whether the current retransmission count has reached the upper limit value (step S504). If the retransmission count does not reach the upper limit value (no in step S504), the receiving apparatus requests the transmitting apparatus to perform retransmission (step S505) and performs a later-described reception buffering process on the received packet (step S508). Note that the receiving apparatus executes processing again from step S501 in accordance with reception of retransmission data in accordance with the retransmission request. Note that the retransmission request is made when the Ack is not received during, for example, an Ack timeout (AckTimeout) time defined by the IEEE802.11 standard. That is, the receiving device may implicitly request retransmission by avoiding action on the transmitting device. Further, the receiving device may explicitly send a retransmission request to the transmitting device using a block ack (block ack) or other signal. If block ACK is used, the receiving device may notify the transmitting device of reception failure by setting a bit corresponding to the sequence number of the packet in which an error is detected to 0 in a block ACK bitmap. Further, the receiving device may transmit a NAK frame as a retransmission request packet. After that, the receiving apparatus performs a later-described reception buffering process (step S508) and ends the process.

On the other hand, if no error is detected in the decoding result of the received data (no in step S503), the receiving apparatus transmits an acknowledgement response frame such as ACK or block ACK to the transmitting apparatus (step S506). If block ACK is used, the receiving apparatus notifies the transmitting apparatus of a packet that has been successfully received using a block ACK bitmap corresponding to a sequence number of the packet. For example, the receiving device may notify the transmitting device that data reception has been successful by setting a bit corresponding to a sequence number of a packet in which an error is not detected in the block ACK bitmap to 1. After that or simultaneously with step S506, the reception apparatus outputs the reception data to a program configured to control an upper layer above a MAC (medium access control) layer (step S507). Further, after that or simultaneously with step S506 or S507, the receiving apparatus performs the above-described reception buffering process (step S508) and ends the process.

In the reception buffering process, the reception apparatus holds an error packet in which an error is detected in a reception buffer (for example, in the storage unit 305) as main data. On the other hand, if no error is detected, or if the retransmission count reaches the upper limit and retransmission is no longer performed, the receiving apparatus discards the main data held in the reception buffer in the reception buffering process.

(frame Structure)

Each of fig. 6 to 8 shows an example of a radio frame (PPDU) (physical layer (PHY) protocol data unit) defined by the IEEE802.11EHT standard and transmitted/received in the processes shown in fig. 4 and 5. Fig. 6 shows an example of an EHT SU (single user) PPDU as a PPDU for single user communication, and fig. 7 shows an example of an EHT MU (multi user) PPDU for multi user communication. Fig. 8 shows an example of an EHT ER (extended range) PPDU for long-distance transmission. The EHT ER PPDU is used when a communication area should be extended in communication between an AP and a single STA.

The PPDU includes fields including an STF (short training field), an LTF (long training field), and a SIG (signal field). As shown in FIG. 6, the PPDU header includes L (legacy) -STF 601, L-LTF 602, and L-SIG 603 to ensure backward compatibility with the IEEE802.11a/b/g/n/ax standard. Note that each frame format shown in fig. 7 and 8 includes L-STF (L-STF 701 or 801), L-LTF (L-LTF 702 or 802), and L-SIG (L-SIG 703 or 803)). Note that the L-LTF is arranged immediately after the L-STF, and the L-SIG is arranged immediately after the L-LTF. Note that each of the structures shown in fig. 6 to 8 further includes RL-SIG (repeat L-SIG, RL-SIG 604, 704, or 804) arranged immediately after the L-SIG. In the RL-SIG field, the contents of the L-SIG are repeatedly transmitted. RL-SIG is used to enable the receiving side to recognize that the PPDU conforms to a standard following the ieee802.11ax standard and may be omitted in IEEE802.11EHT in some cases. In addition, instead of the RL-SIG, a field for enabling the receiving side to recognize that the PPDU conforms to IEEE802.11EHT may be provided.

The L-STF 601 is used for detection of PHY frame, AGC (automatic gain control), timing detection, and the like. The L-LTF 602 is used for highly accurate frequency/time synchronization, acquisition of propagation channel information (CSI: channel state information), and the like. The L-SIG 603 is used to transmit control information including information such as a data transmission rate and a PHY frame length. Legacy devices that comply with the IEEE802.11a/b/g/n/ax standard may decode the various legacy fields described above.

Each PPDU also includes further EHT-SIGs (EHT-SIG-A605, EHT-SIG-A705, EHT-SIG-B706, or EHT-SIG-A805) arranged immediately after the RL-SIG and used to transmit control information for the EHT. Each PPDU also includes a STF for EHT (EHT-STF 606, 707, or 806) and an LTF for EHT (EHT-LTF 607, 708, or 807). Each PPDU includes a data field 608, 709, or 808 and a packet extension field 609, 710, or 809 following these control fields. The portion including fields from L-STF to EHT-LTF of each PPDU is referred to as a PHY preamble. Note that the respective fields of the respective PPDUs may not necessarily be arranged in the order shown in the respective drawings in fig. 6 to 8, or may include new fields not shown in the respective drawings in fig. 6 to 8.

Note that each of fig. 6 to 8 shows a PPDU capable of ensuring backward compatibility as an example. However, if backward compatibility is not required to be ensured, the legacy field may be omitted, for example. In this case, synchronization is established, for example, using EHT-STF and EHT-LTF instead of L-STF and L-LTF. Then, one of the plurality of EHT-LTFs and the EHT-STF following the EHT-SIG field may be omitted.

As shown in tables 1 and 2 below, EHT-SIG-a 605 and 805 included in the EHT SU PPDU and the EHT ER PPDU include EHT-SIG-a1 and EHT-SIG-a2, respectively, which are required to receive the PPDU. In the present embodiment, the HARQ subfield indicating whether to use HARQ at the time of transmission of data included in the data field of the PPDU is included in the EHT-SIG-a 1. Further, the EHT-SIG-A705 of the EHT MU PPDU shown in FIG. 7 includes EHT-SIG-A1 and EHT-SIG-A2 required to receive the PPDU as shown in tables 3 and 4 below. In the present embodiment, the HARQ subfield as described above is included in the EHT-SIG-a 2. For example, when HARQ is used, 1 is set in the HARQ subfield. When HARQ is not used, 0 is set in the HARQ subfield. However, this is merely an example. Conversely, when HARQ is used, 0 may be set in the HARQ subfield, and when HARQ is not used, 1 may be set in the HARQ subfield. Note that the configurations of table 1 to table 4 are merely examples, and information of HARQ may be notified at a position other than the 15 th bit of the EHT-SIG-a1 field, for example, in the EHT SU PPDU and the EHT ER PPDU. Similarly, in the EHT MU PPDU, information of HARQ may be notified at a position other than the 8 th bit of the EHT-SIG-a2 field. The names and contents of the fields may be different from those shown in tables 1 to 4.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

Note that the EHT-SIG-B706 of the EHT MU PPDU includes information of the common field as shown in table 5 and information of the user block field as shown in table 6, which are necessary for receiving the PPDU.

[ Table 5]

[ Table 6]

As shown in table 6, in the user block field, a user field is included, and information of each user is stored. The format of the user field varies depending on whether data is transmitted to a plurality of users through OFDMA or data is transmitted through MU-MIMO. Table 7 shows user fields when data is transmitted through OFDMA, and table 8 shows user fields when data is transmitted through MU-MIMO.

[ Table 7]

[ Table 8]

Whether to use HARQ for data transmission to a user (a plurality of partner devices of a transmitting device) is set in an HARQ subfield of a user field. Note that the HARQ subfield of the EHT-SIG-a2 may be omitted if provided in the user field. In addition, if the HARQ subfield is provided in the EHT-SIG-a2, the HARQ subfield of the user field may be omitted. The HARQ subfield may be provided in both the EHT-SIG-a2 and the user field. For example, whether to use HARQ for data transmission to each user may be specified in the HARQ subfield of the EHT-SIG-a2, and the type of HARQ may be specified in the HARQ subfield of the user field.

In the above manner, the communication apparatus can activate the HARQ control unit 303 according to reception of a radio frame using HARQ, and turn off the HARQ control unit 303 at a timing other than that. As a result, waste of power consumption of the communication apparatus can be suppressed. Further, for example, in a communication apparatus including a plurality of communication processing units configured to process data simultaneously, a series of data transmitted using HARQ may be distributed to a first communication processing unit, and data transmitted without using HARQ may be distributed to a second communication processing unit. This makes it possible to easily process a set of data having a predetermined relationship with each other at once. At this time, when the decoding of the physical header is completed, the data distribution destination can be quickly distributed. Therefore, the simultaneous processing of data can be efficiently performed. Note that, in addition to the AP 102 and the STAs 103 to 105 as communication devices, an information processing device (e.g., a radio chip) for generating the above-described PHY preamble may also implement the present invention.

In the above example, the case where the HARQ subfield is a 1-bit field indicating whether or not HARQ is used has been described. However, the present invention is not limited thereto. For example, the HARQ subfield may be prepared as a field of two or more bits, and may set not only a value indicating whether HARQ is used, but also a value indicating a type of HARQ in the case of using HARQ if HARQ is used. Further, for example, in the above example, if the HARQ subfield of the EHT-SIG-a1 or EHT-SIG-a2 is set to 1, the EHT-SIG-A3 added as a part of the EHT-SIG-a may be included in the radio frame. For example, the EHT-SIG-a3 may include a HARQ type subfield indicating the HARQ type to be used. The type of HARQ may be shown such that, for example, Chase combining is represented by the HARQ type subfield set to 0, incremental redundancy is represented by the HARQ type subfield set to 1, and partial Chase combining is represented by the HARQ type subfield set to 2. Note that these are merely examples, and the type and the bit may be associated in another pattern. The HARQ type subfield does not always have to be provided as a part of the EHT-SIG-a. For example, another signal field may be prepared between the EHT-SIG-A and the EHT-STF (or EHT-SIG-B). In this case, the HARQ type subfield may be set in the signal field. The PHY preamble of the PPDU used in the IEEE802.11EHT standard informs a receiving device of the type of HARQ used for transmission of transmission data. The reception apparatus may switch the method of HARQ used in the data reception process according to the type of HARQ used. At this time, when, for example, the PHY preamble of the PPDU is acknowledged, the receiving apparatus may activate a communication processing function in the HARQ method to be used and turn off a communication processing function in the HARQ method not to be used.

The present invention can be implemented by supplying a program for implementing one or more functions of the above-described embodiments to a system or an apparatus via a network or a storage medium and causing one or more processors in a computer of the system or apparatus to read out and execute the program. The invention may also be implemented by a circuit (e.g., an ASIC) for performing one or more functions.

The present invention is not limited to the above-described embodiments, and various changes and modifications can be made within the spirit and scope of the present invention. Therefore, to apprise the public of the scope of the present invention, the appended claims are made.

This application claims priority from japanese patent application No. 2019-036404, filed on 28.2.2019, which is hereby incorporated by reference.