阅读说明：本技术 支持窄带物联网的无线通信系统中的终端和基站之间的信号发送/接收方法和支持该方法的设备 (Signal transmitting/receiving method between terminal and base station in wireless communication system supporting narrowband internet of things and device supporting same ) 是由 朴昶焕 安俊基 尹硕铉 于 2018-02-19 设计创作，主要内容包括：公开一种在支持窄带物联网(NB-IoT)的无线通信系统中终端和基站之间的信号发送/接收方法以及支持该方法的设备。更具体地,公开当支持NB-IoT的无线通信系统是时分双工(TDD)系统时终端和基站之间的信号发送/接收方法的描述。(Disclosed are a signal transmission/reception method between a terminal and a base station in a wireless communication system supporting narrowband Internet of things (NB-IoT), and an apparatus supporting the same. More specifically, a description of a signal transmission/reception method between a terminal and a base station when an NB-IoT-enabled wireless communication system is a Time Division Duplex (TDD) system is disclosed.)

1. A method of receiving, by a terminal, a signal from a base station in a wireless communication system supporting narrowband internet of things (NB-IoT), the method comprising:

receiving a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) over a first carrier during different sub-time intervals,

wherein a time interval comprises a plurality of sub-time intervals,

wherein the NPSS is received during an Xth (where X is a natural number) sub-interval in each interval, and

receiving the NSSS during a Y-th (where Y is a natural number) sub-interval in a corresponding time interval at a period of two time intervals; and

receiving a system information block 1-narrowband (SIB1-NB) over a second carrier different from the first carrier during a Yth sub-time interval in a respective time interval with a periodicity of one or more time intervals.

2. The method of claim 1, wherein the first carrier is an anchor carrier and the second carrier is a non-anchor carrier.

3. The method of claim 1, wherein the values of X and Y are different from each other.

4. The method of claim 1, wherein the one time interval is one radio frame and each of the sub-time intervals is one subframe,

wherein the radio frame comprises 10 subframes.

5. The method of claim 4, wherein X is 6 and Y is 1.

6. The method of claim 1, wherein a period of one or more time intervals for transmitting the SIB1-NB corresponds to a period of two time intervals or a period of four time intervals.

7. The method of claim 6, wherein the SIB1-NB is received over the second carrier during a Yth sub-time interval of a time interval in which the NSSS is not transmitted.

8. The method of claim 1, wherein the wireless communication system is a Time Division Duplex (TDD) system.

9. The method of claim 8, wherein when the wireless communication system is a TDD system defined in a 3GPP Long Term Evolution (LTE) system, the wireless communication system does not support uplink/downlink configuration 0 for one radio frame defined in the 3GPP LTE system.

10. A method of transmitting a signal to a terminal by a base station in a wireless communication system supporting narrowband internet of things (NB-IoT), the method comprising:

transmitting a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) over a first carrier during different sub-time intervals,

wherein a time interval comprises a plurality of sub-time intervals,

wherein the NPSS is transmitted during an Xth (where X is a natural number) sub-interval in each interval, and

transmitting the NSSS during a Yth (where Y is a natural number) sub-interval in a corresponding time interval at a period of two time intervals; and

transmitting a system information block 1-narrowband (SIB1-NB) over a second carrier different from the first carrier during a Yth sub-time interval in a respective time interval with a periodicity of one or more time intervals.

11. A terminal for receiving a signal from a base station in a wireless communication system supporting narrowband internet of things (NB-IoT), the terminal comprising:

a receiver; and

a processor operatively coupled to the receiver,

wherein the processor is configured to:

receiving a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) over a first carrier during different sub-time intervals,

wherein a time interval comprises a plurality of sub-time intervals,

wherein the NPSS is received during an Xth (where X is a natural number) sub-interval in each interval, and

receiving the NSSS during a Y-th (where Y is a natural number) sub-interval in a corresponding time interval at a period of two time intervals; and is

Receiving a system information block 1-narrowband (SIB1-NB) over a second carrier different from the first carrier during a Yth sub-time interval in a respective time interval at a periodicity of one or more time intervals.

12. A base station for transmitting signals to terminals in a wireless communication system supporting narrowband internet of things (NB-IoT), the base station comprising:

a transmitter; and

a processor operatively coupled to the transmitter,

wherein the processor is configured to:

transmitting a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) over a first carrier during different sub-time intervals,

wherein a time interval comprises a plurality of sub-time intervals,

wherein the NPSS is transmitted during an Xth (where X is a natural number) sub-interval in each interval, and

transmitting the NSSS during a Yth (where Y is a natural number) sub-interval in a corresponding time interval at a period of two time intervals; and is

Transmitting a system information block 1-narrowband (SIB1-NB) over a second carrier different from the first carrier during a Yth sub-time interval in a respective time interval with a periodicity of one or more time intervals.

Technical Field

The following description relates to a wireless communication system, and more particularly, to a signal transmission/reception method between a terminal and a base station in a wireless communication system supporting narrowband internet of things (NB-IoT), and an apparatus supporting the same.

More specifically, a description of a method of transmitting and receiving signals between a terminal and a base station when a wireless communication system supporting narrowband internet of things (NB-IoT) is a Time Division Duplex (TDD) system is included in the following description.

Background

Wireless access systems have been widely deployed to provide various types of communication services such as voice or data. Generally, a wireless access system is a multiple access system that supports communication for multiple users by sharing available system resources (bandwidth, transmission power, etc.) among them. For example, multiple-access systems include Code Division Multiple Access (CDMA) systems, Frequency Division Multiple Access (FDMA) systems, Time Division Multiple Access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and single carrier frequency division multiple access (SC-FDMA) systems.

In particular, an internet of things (IoT) communication technology is newly proposed. Here, IoT refers to communication that does not involve human interaction. Methods of introducing such IoT communication techniques in cellular-based LTE systems are being further discussed.

Conventional Long Term Evolution (LTE) systems have been designed to support high speed data communications and are therefore considered expensive communication technologies.

However, the internet of things communication technology can be widely used only by reducing the cost.

Reducing bandwidth has been discussed as a cost reduction method. However, in order to reduce the bandwidth, a new frame structure should be designed in the time domain, and interference problems with existing neighboring LTE terminals should also be considered.

Disclosure of Invention

Technical problem

An object of the present invention is to provide a method of transmitting/receiving a synchronization signal between a terminal and a base station in a wireless communication system supporting a narrowband internet of things.

In particular, an object of the present invention is to provide a method of transmitting and receiving a synchronization signal between a terminal and a base station when a wireless communication system is a TDD system.

It will be apparent to those skilled in the art that the objects that can be achieved by the present disclosure are not limited to what has been particularly described hereinabove, and that the above and other objects that can be achieved by the present disclosure will be more clearly understood from the following detailed description.

Technical scheme

The present invention provides a method and apparatus for transmitting/receiving a signal between a terminal and a base station in a wireless communication system supporting a narrowband internet of things.

In one aspect of the present invention, provided herein is a method of receiving, by a terminal, a signal from a base station in a wireless communication system supporting narrowband internet of things (NB-IoT), the method including: receiving a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) through a first carrier during different sub-time intervals, wherein one time interval includes a plurality of sub-time intervals, wherein the NPSS is received during an xth (where X is a natural number) sub-time interval in each time interval, and the NSSS is received during a yth (where Y is a natural number) sub-time interval in a corresponding time interval at a period of 2 time intervals; and receiving a system information block 1-narrowband (SIB1-NB) through a second carrier different from the first carrier during a Y-th sub-time interval in the respective time interval with a periodicity of the one or more time intervals.

In another aspect of the present invention, provided herein is a method of transmitting a signal to a terminal by a base station in a wireless communication system supporting narrowband internet of things (NB-IoT), the method including: transmitting a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) through a first carrier during different sub-time intervals, wherein one time interval includes a plurality of sub-time intervals, wherein the NPSS is transmitted during an xth (where X is a natural number) sub-time interval in each time interval, and the NSSS is transmitted during a yth (where Y is a natural number) sub-time interval in a corresponding time interval at a period of 2 time intervals; and transmitting a system information block 1-narrowband (SIB1-NB) through a second carrier different from the first carrier during a Y-th sub-time interval in the corresponding time interval with a periodicity of the one or more time intervals.

In another aspect of the present invention, there is provided a terminal for receiving a signal from a base station in a wireless communication system supporting narrowband internet of things (NB-IoT), the terminal including: a receiver; a processor operably coupled to the receiver, wherein the processor is configured to receive a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) over a first carrier during different sub-time intervals, wherein a time interval comprises a plurality of sub-time intervals, wherein the NPSS is received during an xth (where X is a natural number) sub-time interval in each time interval, and the NSSS is received during a yth (where Y is a natural number) sub-time interval in a respective time interval at a period of two time intervals; receiving a system information block 1-narrowband (SIB1-NB) through a second carrier different from the first carrier during a Y-th sub-time interval in the corresponding time interval at a period of one or more time intervals.

In another aspect of the present invention, there is provided a base station for transmitting a signal to a terminal in a wireless communication system supporting narrowband internet of things (NB-IoT), the base station including: a transmitter; and a processor operatively coupled to the transmitter.

The processor is configured to transmit a Narrowband Primary Synchronization Signal (NPSS) and a Narrowband Secondary Synchronization Signal (NSSS) over a first carrier during different sub-time intervals, wherein a time interval includes a plurality of sub-time intervals, wherein the NPSS is transmitted during an xth (where X is a natural number) sub-time interval in each time interval, and the NSSS is transmitted during a yth (where Y is a natural number) sub-time interval in a corresponding time interval at a period of 2 time intervals; and transmitting a system information block 1-narrowband (SIB1-NB) through a second carrier different from the first carrier during a Y-th sub-time interval in the corresponding time interval with a period of one or more time intervals.

Here, the first carrier may correspond to an anchor carrier, and the second carrier may correspond to a non-anchor carrier.

Further, X and Y may be set to different values.

One time interval may be one radio frame and each sub-time interval may be one subframe, wherein a radio frame may include 10 subframes.

In this case, X may be 6, and Y may be 1.

The period of the one or more time intervals used to transmit the SIB1-NB may correspond to a period of two time intervals or a period of four time intervals.

The SIB1-NB may be received through the second carrier during a Y-th sub-time interval in a time interval in which NSSS is not transmitted.

The wireless communication system may be a Time Division Duplex (TDD) system.

In this case, when the wireless communication system is a TDD system defined in a 3GPP Long Term Evolution (LTE) system, the wireless communication system may not support the uplink/downlink configuration 0 for one radio frame defined in the 3GPP LTE system.

It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed.

Advantageous effects

As is apparent from the above description, the embodiments of the present disclosure have the following effects.

According to an embodiment of the present invention, the terminal and the base station may transmit and receive NPSS and NSSS through the anchor carrier, while transmitting and receiving signals through the non-anchor carrier in the SIB 1-NB.

In particular, in case of the LTE TDD system, it is difficult for the terminal to know the uplink/downlink configuration established by the base station before receiving the SIB information, and thus the terminal and the base station should be limited to transmitting and receiving NPSS, NSSS, SIB1-NB, etc. through a downlink subframe commonly applicable to all uplink/downlink configurations. In contrast, the present invention provides a method of performing signal transmission/reception by minimizing collisions between signals within limited downlink resources, and thus a terminal and a base station can transmit/receive signals using an optimized transmission/reception method.

Those skilled in the art will appreciate that the effects that can be achieved by the present disclosure are not limited to what has been particularly described hereinabove, and that other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. In other words, a person skilled in the art may also derive from the examples of the invention unexpected effects according to embodiments of the invention.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and together with the detailed description provide embodiments of the invention. However, the technical features of the present invention are not limited to the specific drawings. The features disclosed in each of these figures are combined with each other to configure new embodiments. Reference numerals in each figure correspond to structural elements.

Fig. 1 is a diagram illustrating a physical channel and a signal transmission method using the physical channel.

Fig. 2 is a diagram illustrating an exemplary radio frame structure.

Fig. 3 is a diagram illustrating an exemplary resource grid for the duration of a downlink slot.

Fig. 4 is a diagram illustrating an exemplary structure of an uplink subframe.

Fig. 5 is a diagram illustrating an exemplary structure of a downlink subframe.

Fig. 6 is a diagram illustrating a self-contained subframe structure applicable to the present invention.

Fig. 7 and 8 are diagrams illustrating a representative method for connecting a TXRU to an antenna unit.

Fig. 9 is a diagram schematically illustrating an exemplary hybrid beamforming structure from the perspective of a transceiver unit (TXRU) and a physical antenna in accordance with the present invention.

Fig. 10 is a diagram schematically illustrating an exemplary beam scanning operation for a synchronization signal and system information during Downlink (DL) transmission according to the present invention.

Fig. 11 is a diagram schematically illustrating arrangement of in-band anchor carriers for an LTE bandwidth of 10 MHz.

Fig. 12 is a diagram schematically illustrating a position where a physical downlink channel and a downlink signal are transmitted in an FDD LTE system.

Fig. 13 is a diagram illustrating exemplary resource allocation for NB-IoT signals and LTE signals in-band mode.

Fig. 14 to 17 are diagrams illustrating various examples of special subframe configurations.

Fig. 18 is a diagram illustrating the meanings of a subframe configuration and a flag according to the CP length in fig. 14 to 17.

Fig. 19 is a diagram schematically illustrating a signal transmission/reception method between a terminal and a base station according to the present invention.

Fig. 20 is a diagram showing a configuration of a terminal and a base station that can implement the proposed embodiment.

Detailed Description

The embodiments of the present disclosure described below are combinations of elements and features of the present disclosure in specific forms. Elements or features may be considered optional unless otherwise specified. Each element or feature may be practiced without being combined with other elements or features. Further, embodiments of the present disclosure may be constructed by combining parts of elements and/or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some structures or elements of any one embodiment may be included in another embodiment, and may be replaced with corresponding structures or features of another embodiment.

In the description of the drawings, detailed descriptions of known processes or steps of the present disclosure will be avoided so as not to obscure the subject matter of the present disclosure. In addition, processes or steps that can be understood by those skilled in the art will not be described.

Throughout the specification, when a certain part "includes" or "includes" a certain component, it means that other components are not excluded, and other components may be further included unless otherwise specified. The terms "unit", "device (-or/er)" and "module (module)" described in the specification indicate a unit for processing at least one function or operation, which may be implemented by hardware, software, or a combination thereof. In addition, the terms "a" or "an", "one", "the", and the like may be used in the context of the present disclosure (and more particularly in the context of the following claims) to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

In the embodiments of the present disclosure, the description is mainly composed of a data transmission and reception relationship between a Base Station (BS) and a User Equipment (UE). The BS refers to a terminal node of a network that directly communicates with the UE. The specific operations described as being performed by the BS may be performed by an upper node of the BS.

That is, it is apparent that, in a network composed of a plurality of network nodes including the BS, various operations for communication with the UE may be performed by the BS or a network node other than the BS. The term "BS" may be replaced with a fixed station, a node B, an evolved node B (eNode B or eNB), an Advanced Base Station (ABS), an access point, etc.

In the embodiments of the present disclosure, the term terminal may be replaced with a UE, a Mobile Station (MS), a Subscriber Station (SS), a mobile subscriber station (MSs), a mobile terminal, an Advanced Mobile Station (AMS), and the like.

The transmitting end is a fixed and/or mobile node providing a data service or a voice service, and the receiving end is a fixed and/or mobile node receiving a data service or a voice service. Therefore, on the Uplink (UL), the UE may serve as a transmitting end and the BS may serve as a receiving end. Similarly, on a Downlink (DL), the UE may serve as a receiving end and the BS may serve as a transmitting end.

Embodiments of the present disclosure may be supported by standard specifications disclosed for at least one of the wireless access systems including: the Institute of Electrical and Electronics Engineers (IEEE)802.xx system, the third generation partnership project (3GPP) system, the 3GPP Long Term Evolution (LTE) system, the 3GPP 5G NR system, and the 3GPP2 system. In particular, embodiments of the present disclosure may be supported by the following standard specifications: 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS36.321, 3GPP TS 36.331, 3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS38.321, and 3GPP TS 38.331. That is, steps or portions in the embodiments of the present disclosure, which are not described to clearly disclose the technical idea of the present disclosure, may be explained by the above standard specifications. All terms used in the embodiments of the present disclosure may be interpreted by a standard specification.

Reference will now be made in detail to embodiments of the present disclosure with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure, rather than to merely show embodiments that can be implemented according to the present disclosure.

The following detailed description includes specific nomenclature to provide a thorough understanding of the disclosure. However, it is apparent to those skilled in the art that other terms may be substituted for specific terms without departing from the technical spirit and scope of the present disclosure.

For example, the term TxOP may be used interchangeably with transmission period or Reserved Resource Period (RRP) in the same sense. In addition, a Listen Before Talk (LBT) procedure for the same purpose as a carrier sense procedure, CCA (clear channel assessment), CAP (channel access procedure) for determining whether a channel state is idle or busy may be performed.

Hereinafter, a 3GPP LTE/LTE-A system, which is an example of a wireless access system, is explained.

Embodiments of the present disclosure may be applied to various wireless access systems such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like.

CDMA may be implemented as a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA 2000. The TDMA may be implemented as a radio technology such as global system for mobile communications (GSM)/General Packet Radio Service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented as a radio technology such as IEEE 802.11(Wi-Fi), IEEE802.16(WiMAX), EEE 802.20, evolved UTRA (E-UTRA), and so on.

UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP LTE is part of an evolved UMTS (E-UMTS) using E-UTRA, employing OFDMA for the DL and SC-FDMA for the UL. LTE-Advanced (LTE-A) is an evolution of 3GPP LTE. Although the embodiments of the present disclosure are described in the context of a 3GPP LTE/LTE-a system in order to clarify technical features of the present disclosure, the present disclosure is also applicable to an IEEE802.16 e/m system and the like.

1.3GPP LTE/LTE-A system

1.1. Physical channel and signal transmitting and receiving method using the same

In a wireless access system, a UE receives information from a base station on the DL and transmits information to the base station on the UL. Information transmitted and received between the UE and the base station includes general data information and various types of control information. There are many physical channels according to the type/usage of information transmitted and received between the base station and the UE.

Fig. 1 illustrates a physical channel and a general signal transmission method using the same, which may be used in an embodiment of the present disclosure.

When the UE is powered on or enters a new cell, the UE performs an initial cell search (S11). Initial cell search involves acquiring synchronization with a base station. Specifically, the UE synchronizes its timing with the base station and acquires information such as a cell Identifier (ID) by receiving a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from the base station.

Then, the UE may acquire information broadcasted in the cell by receiving a Physical Broadcast Channel (PBCH) from the base station.

During initial cell search, the UE may monitor a DL channel state by receiving a downlink reference signal (DLRS).

After the initial cell search, the UE may obtain more detailed system information by receiving a Physical Downlink Control Channel (PDCCH) and receiving a Physical Downlink Shared Channel (PDSCH) based on information of the PDCCH (S12).

To complete the connection with the base station, the UE may perform a random access procedure with the base station (S13 to S16). In the random access procedure, the UE may transmit a preamble on a Physical Random Access Channel (PRACH) (S13), and may receive the PDCCH and a PDSCH associated with the PDCCH (S14). In case of contention-based random access, the UE may additionally perform a contention resolution procedure including transmitting an additional PRACH (S15) and receiving a PDCCH signal and a PDSCH signal corresponding to the PDCCH signal (S16).

After the above procedure, the UE may receive a PDCCH and/or a PDSCH from the base station (S17), and transmit a Physical Uplink Shared Channel (PUSCH) and/or a Physical Uplink Control Channel (PUCCH) to the base station in a general UL/DL signal transmission procedure (S18).

The control information transmitted by the UE to the base station is generally referred to as Uplink Control Information (UCI). The UCI includes hybrid automatic repeat request acknowledgement/negative acknowledgement (HARQ-ACK/NACK), Scheduling Request (SR), Channel Quality Indicator (CQI), Precoding Matrix Index (PMI), Rank Indicator (RI), and the like.

In the LTE system, UCI is generally transmitted on PUCCH periodically. However, if the control information and the traffic data should be transmitted simultaneously, the control information and the traffic data may be transmitted on the PUSCH. In addition, UCI may be transmitted on PUSCH aperiodically after receiving a request/command from the network.

1.2. Resource structure

Fig. 2 illustrates an exemplary radio frame structure used in embodiments of the present disclosure.

Fig. 2(a) shows a frame structure type 1. Frame structure type 1 is applicable to both full Frequency Division Duplex (FDD) systems and half FDD systems.

One radio frame is 10ms (T)_f＝307200·T_s) Long, comprising 20 slots of equal size indexed from 0 to 19. Each slot is 0.5ms (T)_slot＝15360·T_s) Long. One subframe includes two consecutive slots. The ith subframe includes the 2 i-th and (2i +1) -th slots. That is, the radio frame includes 10 subframes. The time required for transmitting one subframe is defined as a Transmission Time Interval (TTI). T is_sIs T_s＝1/(15kHz×2048)＝3.2552×10^-8(about 33ns) the sample time given. One slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols or SC-FDMA symbols in the time domain and a plurality of Resource Blocks (RBs) in the frequency domain.

A slot includes a plurality of OFDM symbols in the time domain. Since OFDMA is adopted for DL in the 3GPP LTE system, one OFDM symbol represents one symbol period. The OFDM symbols may be referred to as SC-FDMA symbols or symbol periods. An RB is a resource allocation unit including a plurality of consecutive subcarriers in one slot.

In a full FDD system, each of the 10 subframes may be used for DL transmission and UL transmission simultaneously during a 10ms duration. The DL transmission and UL transmission are distinguished by frequency. On the other hand, the UE cannot simultaneously perform transmission and reception in the semi-FDD system.

The above radio frame structure is purely exemplary. Accordingly, the number of subframes in a radio frame, the number of slots in a subframe, and the number of OFDM symbols in a slot may be changed.

Fig. 2(b) shows a frame structure type 2. The frame structure type 2 is applied to a Time Division Duplex (TDD) system. One radio frame is 10ms (T)_f＝307200·T_s) Long, including each having a length of 5ms (═ 153600 · T)_s) Two half frames long. Each field includes a respective length of 1ms (30720. T)_s) Five subframes. The ith subframe includes subframes each having a length (T) of 0.5ms_slot＝15360·T_s) And the (2i +1) th slot. T is_sIs T_s＝1/(15kHz×2048)＝3.2552×10^-8(about 33ns) the sample time given.

Type 2 frames include special subframes with three fields: a downlink pilot time slot (DwPTS), a Guard Period (GP), and an uplink pilot time slot (UpPTS). DwPTS is used for initial cell search, synchronization, or channel estimation at the UE, and UpPTS is used for channel estimation at the base station and UL transmission synchronization with the UE. The GP is used to cancel UL interference between UL and DL caused by multipath delay of DL signals.

Table 1 below lists the special subframe configuration (DwPTS/GP/UpPTS length).

[ Table 1]

In addition, in the LTE release-13 system, the configuration of the special subframe (i.e., the length of DwPTS/GP/UpPTS) can be newly configured by considering the number X of additional SC-FDMA symbols, which is provided by a higher layer parameter named "srs-UpPtsAdd" (if this parameter is not configured, X is set to 0). In the LTE release-14 system, a specific subframe configuration #10 is newly added. For a special subframe configuration {3,4,7,8} for normal cyclic prefix in downlink and a special subframe configuration {2,3,5,6} for extended cyclic prefix in downlink, the UE does not want to be configured with 2 additional UpPTS SC-FDMA symbols, for a special subframe configuration {1,2,3,4,6,7,8} for normal cyclic prefix in downlink and a special subframe configuration {1,2,3,5,6} for extended cyclic prefix in downlink, the UE does not want to be configured with 4 additional UpPTS SC-FDMA symbols.

[ Table 2]

Fig. 3 illustrates an exemplary structure of a DL resource grid for the duration of one DL slot that may be used in embodiments of the present disclosure.

Referring to fig. 3, a DL slot includes a plurality of OFDM symbols in the time domain. One DL slot includes 7 OFDM symbols in the time domain and an RB includes 12 subcarriers in the frequency domain, to which the present disclosure is not limited.

Each element of the resource grid is referred to as a Resource Element (RE). RB includes 12x7 REs. Number of RBs in DL slot N^DLDepending on the DL transmission bandwidth.

Fig. 4 illustrates a structure of a UL subframe that may be used in an embodiment of the present disclosure.

Referring to fig. 4, the UL subframe may be divided into a control region and a data region in a frequency domain. A PUCCH carrying UCI is allocated to the control region and a PUSCH carrying user data is allocated to the data region. To maintain the single carrier property, the UE does not transmit PUCCH and PUSCH simultaneously. A pair of RBs in a subframe is allocated to a PUCCH of a UE. The RBs of the RB pair occupy different subcarriers in two slots. Therefore, it can be said that the RB pair hops on the slot boundary.

Fig. 5 illustrates a structure of a DL subframe that may be used in an embodiment of the present disclosure.

Referring to fig. 5, up to three OFDM symbols of a DL subframe starting from OFDM symbol 0 are used as a control region to which a control channel is allocated, and the other OFDM symbols of the DL subframe are used as a data region to which a PDSCH is allocated. DL control channels defined for the 3GPP LTE system include a Physical Control Format Indicator Channel (PCFICH), a PDCCH, and a physical hybrid ARQ indicator channel (PHICH).

The PCFICH is transmitted in the first OFDM symbol of the subframe, carrying information on the number of OFDM symbols used to transmit control channels in the subframe (i.e., the size of the control region). The PHICH is a response channel for UL transmission, and delivers a harq ack/NACK signal. Control information carried on the PDCCH is referred to as Downlink Control Information (DCI). The DCI transmits UL resource allocation information, DL resource allocation information, or UL transmission (Tx) power control commands for a UE group.

2. New radio access technology system

As many communication devices require higher communication capacity, the necessity of greatly improved mobile broadband communication compared to existing Radio Access Technologies (RATs) has increased. In addition, there is also a need for large-scale Machine Type Communication (MTC) capable of providing various services at any time and at any place by connecting several devices or objects to each other. In addition, communication system designs have been proposed that can support reliability and delay sensitive services/UEs.

As a new RAT considering enhanced mobile broadband communication, large-scale MTC, and ultra-reliable and low-delay communication (URLLC), etc., a new RAT system has been proposed. In the present invention, for convenience of description, the corresponding technology is referred to as a new RAT or a New Radio (NR).

2.1. Parameter set

The NR system to which the present invention is applicable supports various OFDM parameter sets shown in the following table. In this case, the value of μ per carrier bandwidth part and cyclic prefix information can be signaled in DL and UL, respectively. For example, the value of μ per downlink carrier bandwidth part and cyclic prefix information may be signaled by DL-BWP-mu and DL-MWP-cp corresponding to higher layer signaling. As another example, the value of μ per uplink carrier bandwidth part and cyclic prefix information may be signaled by UL-BWP-mu and UL-MWP-cp corresponding to higher layer signaling.

[ Table 3]

μ	Δf＝2μ·15[kHz]	Cyclic prefix
			0	15	Is normal
1	30	Is normal
			2	60	Normal, extended
3	120	Is normal
			4	240	Is normal

2.2. Frame structure

DL and UL transmissions are configured with frames of length 10 ms. Each frame may consist of ten subframes each having a length of 1 ms. In this case, the number of consecutive OFDM symbols in each subframe is

In addition, each subframe may be composed of two half-frames having the same size. In this case, the two half frames are composed of subframes 0 to 4 and subframes 5 to 9, respectively.

With respect to the subcarrier spacing μ, the slots may be numbered within one subframe in ascending order as follows:and may also be numbered within the frame in ascending order as follows:in this case, the number of consecutive OFDM symbols in one slot may be determined according to a cyclic prefixAs shown in the table below. Starting time slot of a subframeStarting OFDM symbol of the same subframe as in the time dimensionAnd (4) aligning. Table 4 shows the number of OFDM symbols in each slot/frame/subframe in case of a normal cyclic prefix, and table 5 shows the number of OFDM symbols in each slot/frame/subframe in case of an extended cyclic prefix.

[ Table 4]

[ Table 5]

In the NR system to which the present invention can be applied, a self-contained slot structure can be applied based on the above-described slot structure.

Fig. 6 is a diagram illustrating a self-contained slot structure suitable for use with the present invention.

In fig. 6, a hatched region (e.g., symbol index ═ 0) indicates a downlink control region, and a black region (e.g., symbol index ═ 13) indicates an uplink control region. The remaining region (e.g., symbol index ═ 1 to 13) can be used for DL data transmission or UL data transmission.

Based on this structure, the base station and the UE can sequentially perform DL transmission and UL transmission in one slot. That is, the base station and the UE can not only receive DL data in one slot but also transmit UL ACK/NACK in response to the DL data. Therefore, due to this structure, it is possible to reduce the time required until data retransmission in the event of a data transmission error, thereby minimizing the delay of the final data transmission.

In such a self-contained slot structure, a time interval of a predetermined length is required in order to allow the process of switching the base station and the UE from the transmission mode to the reception mode, and vice versa. For this, in the self-contained slot structure, some OFDM symbols at the time of switching from DL to UL are set as a Guard Period (GP).

Although it is described that the self-contained slot structure includes both the DL control region and the UL control region, these control regions can be selectively included in the self-contained slot structure. In other words, the self-contained slot structure according to the present invention may include a DL control region or an UL control region, and both the DL control region and the UL control region, as shown in fig. 6.

In addition, for example, the slots may have various slot formats. In this case, the OFDM symbol in each slot may be divided into a downlink symbol (denoted by "D"), a flexible symbol (denoted by "X"), and an uplink symbol (denoted by "U").

Therefore, the UE can assume that DL transmission occurs only in symbols denoted by "D" and "X" in the DL slot. Similarly, the UE can assume that UL transmission occurs only in symbols denoted by "U" and "X" in the UL slot.

2.3. Analog beamforming

In the millimeter wave (mmW) system, since the wavelength is short, a plurality of antenna elements can be mounted in the same region. That is, considering that the wavelength in the 30GHz band is 1cm, a total of 100 antenna elements may be mounted in a 5cm by 5cm panel at intervals of 0.5 λ (wavelength) in the case of a two-dimensional array. Accordingly, in mmW systems, coverage or throughput can be improved by increasing Beamforming (BF) gain using multiple antenna elements.

In this case, each antenna unit may include a transceiver unit (TXRU) so that the transmission power and phase of each antenna unit can be adjusted. By doing so, each antenna element is able to perform independent beamforming per frequency resource.

However, it is not cost-effective to install TXRUs in all of the approximately 100 antenna units. Therefore, a method of mapping a plurality of antenna elements to one TXRU using analog phase shifters and adjusting the direction of a beam has been considered. However, since only one beam direction is generated over the entire frequency band, this method has a disadvantage in that frequency selective beamforming is not possible.

To solve this problem, as an intermediate form of digital BF and analog BF, a hybrid BF having fewer B TXRUs than Q antenna elements can be considered. In the case of hybrid BF, the number of beam directions capable of simultaneous transmission is limited to B or less, depending on how the B TXRUs and the Q antenna elements are connected.

Fig. 7 and 8 are diagrams illustrating a representative method for connecting a TXRU to an antenna unit. Here, the TXRU virtualization model represents a relationship between a TXRU output signal and an antenna unit output signal.

Fig. 7 illustrates a method for connecting TXRUs to subarrays. In fig. 7, one antenna unit is connected to one TXRU.

Meanwhile, fig. 8 illustrates a method for connecting all TXRUs to all antenna elements. In fig. 8, all antenna units are connected to all TXRUs. In this case, a separate additional unit is required to connect all antenna units to all TXRUs, as shown in fig. 8.

In fig. 7 and 8, W indicates a phase vector weighted by an analog phase shifter. That is, W is the main parameter that determines the analog beamforming direction. In this case, the mapping relationship between the CSI-RS antenna ports and the TXRU may be 1:1 or 1 to many.

The configuration shown in fig. 7 has a disadvantage in that it is difficult to achieve beamforming focusing, but has an advantage in that all antennas can be configured at low cost.

In contrast, the configuration shown in fig. 8 has an advantage in that beam-forming focusing can be easily achieved. However, since all antenna units are connected to the TXRU, it has a disadvantage of high cost.

When a plurality of antennas are used in the NR system to which the present invention is applicable, a hybrid Beamforming (BF) scheme in which digital BF and analog BF are combined may be applied. In this case, analog BF (or Radio Frequency (RF) BF) means an operation of performing precoding (or combining) at an RF stage. In hybrid BF, each of a baseband stage and an RF stage performs precoding (or combining), and thus, performance similar to digital BF can be achieved while reducing the number of RF chains and the number of digital-to-analog (D/a) (or analog-to-digital (a/D)) converters.

For ease of description, the hybrid BF structure may be represented by N transceiver units (TXRUs) and M physical antennas. In this case, the digital BF for the L data layers transmitted by the transmitting end may be represented by an N × L matrix. The N converted digital signals obtained thereafter are converted into analog signals via the TXRU, and then subjected to analog BF, which is represented by an M × N matrix.

Fig. 9 is a diagram schematically illustrating an exemplary hybrid BF structure from the perspective of a TXRU and a physical antenna in accordance with the present invention. In fig. 9, the number of digital beams is L, and the number of analog beams is N.

In addition, in the NR system to which the present invention can be applied, the base station designs the analog BF to be changed in units of symbols to provide more effective BF support to UEs located in a specific area. Further, as illustrated in fig. 9, when N specific TXRUs and M RF antennas are defined as one antenna panel, the NR system according to the present invention considers introducing a plurality of antenna panels to which independent hybrid BF is applicable.

In the case where the base station utilizes a plurality of analog beams as described above, the analog beams advantageous for signal reception may differ depending on the UE. Therefore, in the NR system to which the present invention can be applied, a beam scanning operation is being considered in which a base station transmits signals (at least synchronization signals, system information, paging, etc.) by applying different analog beams in a specific Subframe (SF) on a symbol-by-symbol basis so that all UEs can have reception opportunities.

Fig. 10 is a diagram schematically illustrating an exemplary beam scanning operation for a synchronization signal and system information in a DL transmission procedure according to the present invention.

In the following fig. 10, a physical resource (or physical channel) which transmits system information of the NR system to which the present invention is applicable in a broadcast manner is referred to as xPBCH. Here, analog beams belonging to different antenna panels within one symbol may be transmitted simultaneously.

As illustrated in fig. 10, in order to measure a channel of each analog beam in the NR system to which the present invention can be applied, an introduction beam RS (brs), which is a Reference Signal (RS) transmitted by applying a single analog beam (corresponding to a specific antenna panel), is being discussed. A BRS may be defined for multiple antenna ports, and each antenna port of the BRS may correspond to a single analog beam. In this case, unlike the BRS, a synchronization signal or xPBCH can be transmitted by applying all analog beams in the analog beam group so that any UE can receive a signal well.

3. Narrow-band Internet of things (NB-IoT)

Hereinafter, technical features of the NB-IoT will be described in detail. Although the NB-IoT system based on the 3GPP LTE standard will be mainly described for simplicity, the same configuration is also applicable to the 3GPP NR standard. To this end, some technical configurations may be modified (e.g. sub-frame- > slot)

Although the NB-IoT technology will be described in detail below based on the LTE standard technology, the LTE standard technology can be replaced with the NR standard technology within a range easily derived by those skilled in the art.

3.1. Mode of operation and frequency

The NB-IoT supports three modes of operation, intra-band, guard-band, and independent, and the same requirements apply to each mode.

(1) In the in-band mode, some resources in a Long Term Evolution (LTE) band are allocated to the NB-IoT.

(2) In the guard-band mode, the LTE guard band is utilized, and the NB-IoT carriers are arranged as close as possible to the LTE edge subcarriers.

In the standalone mode, some carriers in a global system for mobile communications (GSM) band are allocated and operated separately.

The NB-IoT UE searches for the anchor carrier in units of 100kHz for initial synchronization, and the anchor carrier center frequencies of the in-band and guard-band should be within ± 7.5kHz from the channel grid of the 100kHz channel. In addition, in LTE PRBs, 6 middle PRBs are not allocated to NB-IoT. Thus, the anchor carrier may be located only on a particular Physical Resource Block (PRB).

Fig. 11 is a diagram schematically illustrating arrangement of in-band anchor carriers for an LTE bandwidth of 10 MHz.

As shown in fig. 11, Direct Current (DC) subcarriers are positioned at the channel grid. Since the center frequency interval between adjacent PRBs is 180kHz, the PRB indices 4, 9, 14, 19, 30, 35, 40, and 45 have center frequencies of ± 2.5kH from the channel grid.

Similarly, in the case of a bandwidth of 20MHz, the center frequency of the PRBs suitable for anchor carrier transmission is located at ± 2.5kHz from the channel grid, and at ± 7.5kHz for bandwidths of 3MHz, 5MHz, and 15 MHz.

In the guard band mode, PRBs immediately adjacent to edge PRBs of LTE are positioned ± 2.5kHz from the channel grid with bandwidths of 10MHz and 20 MHz. In the case of 3MHz, 5MHz, and 15MHz, the center frequency of the anchor carrier may be located at ± 7.5kHz from the channel grid by using guard bands corresponding to three subcarriers from the edge PRB.

The standalone mode anchor carrier is aligned with the 100kHz channel grid and all GSM carriers, including the DC carrier, can be used as NB-IoT anchor carriers.

In addition, NB-IoT supports operation of multiple carriers, and in-band + in-band, in-band + guard band, guard band + guard band, and independent + independent combinations may be used.

3.2. Physical channel

3.2.1. Downlink (DL)

For the NB-IoT downlink, an Orthogonal Frequency Division Multiple Access (OFDMA) scheme with 15kHz subcarrier spacing is employed. This scheme provides orthogonality between subcarriers to facilitate coexistence with LTE systems.

On the downlink, physical channels such as a Narrowband Physical Broadcast Channel (NPBCH), a Narrowband Physical Downlink Shared Channel (NPDSCH), and a Narrowband Physical Downlink Control Channel (NPDCCH) are provided, and a narrowband secondary synchronization signal (NPSS), a narrowband primary synchronization signal (NSSS), and a Narrowband Reference Signal (NRS) are provided as physical signals.

Fig. 12 is a diagram schematically illustrating a position where a physical downlink channel and a downlink signal are transmitted in an FDD LTE system.

As shown in fig. 12, NPBCH is transmitted in the first subframe of each frame, NPSS is transmitted in the sixth subframe of each frame, and NSSS is transmitted in the last subframe of each even frame.

The NB-IoT UE should acquire system information about the cell in order to access the network. For this purpose, synchronization with the cell should be obtained through a cell search procedure, and a synchronization signal (NPSS, NSSS) is transmitted on the downlink for this purpose.

The NB-IoT UE acquires frequency, symbol, and frame synchronization using the synchronization signal and searches 504 physical cell ids (pcids). The LTE synchronization signal is designed to be sent on 6 PRB resources and is not reusable for NB-IoT using 1 PRB.

Therefore, new NB-IoT synchronization signals have been designed, and the three operating modes of NB-IoT are designed in the same way.

More specifically, the NPSS, which is a synchronization signal in the NB-IoT system, is composed of a Zadoff-chu (zc) sequence having a sequence length of 11 and a root index value of 5.

Here, NPSS may be generated according to the following equation.

[ equation 1]

Here, S (1) for the symbol index l may be defined as shown in the following table.

[ Table 6]

NSSS, which is a synchronization signal in an NB-IoT system, is composed of a combination of a ZC sequence of a sequence length of 131 and a binary scrambling sequence such as a Hadamard sequence. Specifically, the NSSS indicates the PCID to the NB-IoT UE in the cell through a combination of sequences.

Here, NSSS may be generated according to the following equation.

[ equation 2]

Here, the parameters in equation 2 may be defined as follows.

[ Table 7]

Binary sequence b_q(m) can be defined as shown in the following table, and the number of frames n_fCyclic shift of theta_fCan be defined by the equation given below.

[ Table 8]

[ equation 3]

NRS is provided as a reference signal for channel estimation required for physical downlink channel demodulation, and is generated in the same manner as in LTE. However, NB narrowband-physical cell id (pcid) is used as an initial value for initialization.

The NRS is transmitted to one or two antenna ports and the base station supporting up to two NB-IoT transmit antennas.

The NPBCH carries to the UE a master information block narrowband (MIB-NB) which is the minimum system information that the NB-IoT UE should know to access the system.

The Transport Block Size (TBS) of the MIB-NB is 34 bits, is updated and transmitted at a Transmission Time Interval (TTI) period of 640ms, and includes information such as an operation mode, a System Frame Number (SFN), a hyper-SFN, a cell-specific reference signal (CRS) port number, and a channel grid offset.

The NPBCH signal may be repeatedly transmitted a total of 8 times to improve coverage.

NPDCCH has the same transmit antenna configuration as NPBCH, and supports three types of Downlink Control Information (DCI) formats. DCI N0 is used to transmit scheduling information of a Narrowband Physical Uplink Shared Channel (NPUSCH) to a UE, and DCIs N1 and N2 are used to transmit information required for demodulation of NPDSCH to the UE. The transmission of NPDCCH may be repeated up to 2048 times to improve coverage.

NPDSCH is a physical channel for transmitting a transport channel (TrCH) such as a downlink shared channel (DL-SCH) or a Paging Channel (PCH). The maximum TBS is 680 bits and the transmission may be repeated up to 2048 times to improve coverage.

3.2.2. Uplink (UL)

The uplink physical channels include a Narrowband Physical Random Access Channel (NPRACH) and NPUSCH, and support single tone transmission and multi-tone transmission.

Multi-tone transmission is supported only for subcarrier spacing of 15kHz and single tone transmission is supported for subcarrier spacing of 3.5kHz and 15 kHz.

On the uplink, the 15Hz subcarrier spacing may maintain orthogonality with LTE, providing optimal performance. However, a subcarrier spacing of 3.75kHz may reduce orthogonality, resulting in performance degradation due to interference.

The NPRACH preamble consists of four symbol groups, wherein each symbol group consists of a Cyclic Prefix (CP) and five symbols. NPRACH only supports single tone transmission with 3.75kHz subcarrier spacing and provides CPs of 66.7 μ s and 266.67 μ s in length to support different cell radii. Each symbol group performs frequency hopping, and the frequency hopping pattern is as follows.

The subcarriers used to transmit the first symbol group are determined in a pseudo-random manner. The second symbol group skips one subcarrier, the third symbol group skips six subcarriers, and the fourth symbol group skips one subcarrier hop.

In case of repeated transmission, the frequency hopping procedure is repeatedly applied. To improve coverage, the NPRACH preamble may be repeatedly transmitted up to 128 times.

NPUSCH supports two formats. Format 1 is used for UL-SCH transmission and its maximum Transport Block Size (TBS) is 1000 bits. Format 2 is used for transmitting uplink control information such as HARQ ACK signaling. Format 1 supports both single-tone and multi-tone transmissions, and format 2 supports only single-tone transmissions. In single tone transmission, p/2 Binary Phase Shift Keying (BPSK) and p/4-QPSK (Quadrature phase shift keying) are used to reduce the peak to average power ratio (PAPR).

3.2.3. Resource mapping

In the independent and guard-band mode, all resources included in 1 PRB may be allocated to NB-IoT. However, in the in-band mode, resource mapping is limited in order to maintain orthogonality with existing LTE signals.

Without system information, the NB-IoT UE should detect NPSS and NSSS for initial synchronization. Therefore, resources classified as the LTE control channel allocation region (OFDM symbols 0 to 2 in each subframe) cannot be allocated to NPSS and NSSS, and NPSS and NSSS symbols mapped to Resource Elements (REs) overlapping with LTE CRS should be punctured.

Fig. 13 is a diagram illustrating exemplary resource allocation for NB-IoT signals and LTE signals in-band mode.

As shown in fig. 13, for convenience of implementation, NPSS and NSSS are not transmitted on the first three OFDM symbols in a subframe corresponding to a transmission resource region of a control channel in the conventional LTE system regardless of an operation mode. Common Reference Signals (CRS) in the legacy LTE system and REs of NPSS/NSSS colliding on physical resources are punctured and mapped so as not to affect the legacy LTE system.

After cell search, the NB-IoT UE demodulates NPBCH without system information other than PCID. Therefore, NPBCH symbols cannot be mapped to the LTE control channel allocation region. Since four LTE antenna ports and two NB-IoT antenna ports should be assumed, REs allocated to CRS and NRS cannot be allocated to NPBCH. Therefore, NPBCH should be rate matched according to the given available resources.

After demodulating NPBCH, the NB-IoT UEs may acquire information about CRS antenna port numbers, but may still not know information about LTE control channel allocation regions. Accordingly, NPDSCH for transmitting system information block type 1(SIB1) data is not mapped to resources classified as an LTE control channel allocation region.

However, unlike the case of NPBCH, REs not allocated to LTE CRS may be allocated to NPDSCH. Because the NB-IoT UE has acquired all information related to resource mapping after receiving SIB1, NPDSCH (except for the case of transmitting SIB1) and NPDCCH may be mapped to available resources based on LTE control channel information and CRS antenna port numbers.

4. Proposed embodiments

Hereinafter, the present invention will be described in more detail based on the technical concept disclosed above.

NB-IoT in legacy LTE systems is designed to be supportable only in the normal Cyclic Prefix (CP) of Frequency Division Duplex (FDD) systems. For the anchor carrier on which the synchronization signals (e.g., Narrowband Primary Synchronization Signal (NPSS), Narrowband Secondary Synchronization Signal (NSSS), master information block-narrowband (MIB-NB), and system information block type 1-NB transmission (SIB1-NB)) are transmitted, the transmission subframe location of each channel is fixed in the time domain, as shown in the table given below.

[ Table 9]

Here, NPSS and NPBCH are transmitted in subframes 0 and 5 of each radio frame, respectively, while NSSS is transmitted only in subframe 9 of an even-numbered radio frame. In addition, a SIB1-NB (system information block type 1-NB) may be transmitted in subframe 4 in every other frame of 16 consecutive radio frames, where the period and starting position of the 16 radio frames may be according toAnd schedulinglnfossib 1. However, even if the subframe is not used for SIB-1NB transmission in a particular cell, SIB1-NB transmission may be performed in subframe 4 in another cell.

Therefore, there is a need to transmit at least 4 DL subframes on the anchor carrier for NB-IoT services, and at least 5 DL subframes should ensure CarrierConfigDedicated-NB transmission for random access response and for non-anchor carrier configuration.

On the other hand, in the TDD system, the number of DL subframes in a radio frame may be limited according to UL/DL configuration, as shown in the following table.

[ Table 10]

Here, D, U and S denote downlink, uplink, and special subframes, respectively. For an eNB supporting enhanced interference mitigation and traffic adaptation (eIMTA) features, a portion of a UL subframe may be dynamically changed to a DL subframe.

DwPTS and UpPTS are configured before and after the special subframe existing between DL and UL intervals, respectively. The gap between DwPTS and UpPTS is used for downlink-to-uplink handover and Timing Advance (TA). As described above, the configuration of OFDM or SC-FDMA symbol levels in the special subframe may be represented as shown in fig. 14 to 17 according to CP lengths of downlink and uplink and a higher layer parameter srs-UpPtsAdd. Here, as described above, X (srs-UpPtsAdd) may not be set to 2 for the special subframe configuration {3,4,7,8} of the normal CP in the downlink and the special subframe configuration {2,3,5,6} of the extended CP in the downlink. In addition, X (srs-UpPtsAdd) may not be set to 4 for the special subframe configuration {1,2,3,4,6,7,8} of the normal CP in the downlink and the special subframe configuration {1,2,3,5,6} of the extended CP in the downlink.

Fig. 14 is a diagram illustrating a special subframe configuration to which a normal CP in DL and a normal CP in UL are applied.

Fig. 15 is a diagram illustrating a special subframe configuration to which a normal CP in DL and an extended CP in UL are applied.

Fig. 16 is a diagram illustrating a special subframe configuration to which an extended CP in DL and a normal CP in UL are applied.

Fig. 17 is a diagram illustrating a special subframe configuration to which an extended CP in DL and an extended CP in UL are applied.

Fig. 18 is a diagram illustrating the meanings of a flag and a subframe configuration according to the CP length in fig. 14 to 17. As shown in fig. 18, a subframe according to the extended CP is composed of 12 symbols, and a subframe according to the normal CP is composed of 14 symbols. Here, each DL symbol and UL symbol may be represented as shown at the bottom in fig. 18. Hereinafter, it is assumed that the same structure as described above is applied to the present invention.

Here, for convenience of explanation and expression, it is assumed that the index n of the nth downlink/uplink symbol and the additional downlink/uplink symbol of the DwPTS/UpPTS conforms to the index number of fig. 18. That is, in each configuration, the starting index of n _ U may not be 0.

In fig. 14 to 17, the space-time segment of the DwPTS and UpPTS periods may be used by a UE (e.g., NB-IoT UE) as a DL-to-UL handover gap and may be configured to be about 20 microseconds, which is about 1/3 times shorter than the period of an OFDM or SC-FDMA symbol. Further, n-a (X, y) in each row represents a default type of the nth special subframe configuration having a dwPTS period and a UpPTS period including X OFDM symbols and y SC-FDMA symbols, and n-B (X, y +2) and n-C (X, y +4) represent special subframe configurations in which the number of SC-FDMA symbols is increased from the default type n-a (X, y) according to the value of X (srs-UpPtsAdd).

As described above, in the TDD system, the number of subframes fixed to the downlink may vary according to the UL/DL configuration, and even the number of OFDM symbols fixed to the downlink in the special subframe may vary according to the special subframe configuration.

However, when supporting the eIMTA feature, the eNB may be allowed to dynamically change a portion of the uplink subframes to downlink subframes.

However, given the fixed scheduling of NPSS, NSSS, NPBCH, and SIB1-NB for NB-IoT systems, an eIMTA scheme in which a particular uplink subframe is always changed to a downlink subframe may not be desirable.

Therefore, in order to support NB-IoT in a TDD system, it is necessary to design a structure capable of supporting as many available downlink subframes or OFDM symbols as possible according to a combination of various UL/DL configurations and special subframe configurations.

To design an NB-IoT anchor carrier structure suitable for a TDD system, the following items or constraints may be considered.

1. Mode of operation

The NB-IoT supports four modes of operation (in-band same PCI, in-band different PCI, guardband, independent). The operation mode of the anchor carrier is transmitted in the MIB-NB of the NPBCH. Accordingly, there is a need to provide an NB-IoT channel structure in which NB-IoT UEs can perform the same synchronization regardless of the mode of operation, up to the detection and decoding of NPSS, NSSS, and NPBCH of the NB-IoT UEs. Otherwise, the NB-IoT UE needs to add blind detection and decoding according to the operation mode. This architecture is not suitable for NB-IoT modems, which have the features of "low cost and long battery life".

UL/DL configuration and special subframe configuration

As can be seen from table 10, subframe 0 and subframe 5 are downlink subframes that may be commonly used for all UL/DL configurations. Subframe 1 may always be configured as a partial downlink subframe, and subframe 6 may be configured as a partial downlink subframe or a full downlink subframe (a subframe in which all symbols are configured for downlink OFDM) according to the UL/DL configuration.

Thus, to support NB-IoT in all UL/DL configurations, only subframes 0 and 5 may be used as full downlink subframes.

On the other hand, when another NB-IoT channel structure is designed according to the UL/DL configuration and the special subframe configuration to ensure another downlink subframe or OFDM symbol as a full downlink subframe, blind detection and decoding may be added. This structure is not suitable for NB-IoT modems with "low cost and long battery life" features.

3. Reusing NPSS and NSSS of LTE Release 14

As described above, NPSS and NSSS are defined in the 3GPP standard.

More specifically, the NPSS includes the Zadoff-Chu sequence and the cover sequence of table 4, and is allocated to 11 OFDM symbols except for the first 3 OFDM symbols of the subframe for transmission.

In addition, the NSSS performs phase rotation according to the binary sequence and frame number of table 8 based on the Zadoff-Chu sequence, and then is allocated to 11 OFDM symbols except for the first three OFDM symbols of the subframe, as in the case of the NPSS, so that transmission is performed.

In other words, in order to allocate NPSS and NSSS, one PRB pair having 12 Resource Elements (REs) is required in the frequency domain, and 12 OFDM symbols are required in the time domain. In addition, NPSS and NSSS may be positioned on consecutive OFDM symbols such that it is assumed that there is a little variation in the channel in each sequence in the time domain. If some symbols in each sequence are non-consecutively arranged in the time domain, decoding performance may be degraded.

Therefore, even in NB-IoT of the TDD system, NPSS and NSSS need to be allocated to at least 11 consecutive OFDM symbols in the time domain.

4. Reusing LTE Release 14 NPBCH

NPBCH is transmitted on 11 consecutive OFDM symbols in each subframe 0. However, unlike NPSS and NSSS, the MIB-NB having a payload of 34 bits (having a space of 11 bits) and a Cyclic Redundancy Check (CRC) of 16 bits is subjected to 1/3 tail-biting convolutional code (TBCC) coding and rate matching, and then QPSK modulated so as to be transmitted within 640 milliseconds.

Then, the NPBCH can be demodulated and decoded through channel estimation based on a Narrowband Reference Signal (NRS).

Thus, unlike NPSS and NSSS, NPBCH does not need to have 11 consecutive OFDM symbols in the time domain. Even when transmitted on non-contiguous OFDM symbols, only including NRS four channel estimates in non-contiguous OFDM symbol intervals can be designed by changing the existing structure.

However, in order to support the same modulation order (QPSK) and code rate as the existing NPBCH, it needs to be allocated to 11 OFDM symbols in a radio frame, or 100 REs in addition to 4-port CRS REs and 2-port NRS REs.

In this case, if different PBCH structures are designed according to the operation mode and UL/DL configuration, they may not be suitable for NB-IoT modems with "low cost and long battery life" features from the perspective of NB-IoT UEs, because of the added blind detection and decoding.

In the present invention, based on the above considerations and constraints, a detailed description will be given of the structures and arrangements of synchronization signals (NPSS and NSSS), channels (NPBCH), NRS-B (which is a reference signal for PBCH demodulation and may be different from NRS of NPDSCH and/or NPDCCH), and SIB1-NB for TDD systems, and a signal transmission/reception method based thereon.

4.1. The first proposal is as follows: "Default Carrier designated for NPBCH and SIB 1-NB"

In this section, UL/DL configuration 0 has the minimum number of downlink subframes as a way to support NB-IoT operation in all UL/DL configurations, the arrangement of NPSS and NSSS or NSSS and NPSS is transmitted and received in subframe 0 and subframe 5 based on UL/DL configuration 0. Here, the body transmitting the NPSS and/or NSSS may be an eNB, and the body receiving the NPSS and/or NSSS may be an NB-IoT UE.

Here, since a full downlink subframe capable of transmitting NPBCH and SIB1-NB may be insufficient, NPBCH and SIB1-NB may be transmitted on a non-anchor carrier in the present invention.

However, since the non-anchor carrier operation is defined as the capability of the UE, there may be a case where non-anchor configuration is impossible according to the capability of the UE. When the configuration is established so as not to support UL/DL configuration 0, particularly for NB-IoT UEs supporting only single carrier operation, ambiguity may occur for the NB-IoT UEs because UL/DL configuration is not identifiable using only sequence information on NPSS and NSSS. Thus, it is difficult for the eNB to expect proper operation of the NB-IoT UE.

Therefore, to support NB-IoT operation in all TDD UL/DL configurations, it is necessary to assume that non-anchor carrier operation of the UE is mandatory. In this case, the TDD NB-ioute may detect NPSS and NSS on the anchor carrier, change the frequency to a special default carrier, and expect to receive NPBCH and SIB1-NB on the non-anchor carrier.

Here, a default non-anchor carrier on which NPBCH and SIB1-NB can be transmitted (and random access can be performed) may be referred to as a second anchor carrier. This operation may be predefined by an equation representing the relationship between the anchor carrier and the second anchor carrier using a similar method as the E-UTRA absolute radio frequency channel number (EARFCN), or may be predefined as a specific offset value. Here, a method similar to EARFCN may be defined as the following equation.

[ equation 4]

F_UL＝F_{DL_low}+0.1(N_DL-N_Offs，DL)+0.0025(2M_DL+1)+f(M_DL)[MHz]

Here, F_ULAndrespectively represent the second anchor carrier frequency and the lowest frequency (constant) of the corresponding frequency band, and N_DL、N_Offs，DLAnd M_DLIndicates the downlink EARFCN number,An offset value for calculating the downlink EARFCN, and the NB-IoT downlink channel number. In addition, f (M)_DL) Represents a function indicating a relative offset between the anchor carrier and the second anchor carrier, and may have a value greater than or equal to 0. f (M)_DL) Is set to be band agnostic or band agnostic, and its value may be limited considering 3MHz, which is the minimum LTE bandwidth capable of performing NB-IoT operations. In other words, at 3MHz, only the PRB2 or 12 is allowed to be used as an anchor carrier, and the assignable second anchor carrier may be set to one of 8 values except for the central 6 RBs or anchor carrier.

NPSS, NSSS, and NPBCH may be configured to be transmitted on an anchor carrier, and only SIB1-NB may be configured to be transmitted on a second anchor carrier. This configuration may even apply to the case where NB-IoT is not supported in UL-DL configuration 0. In this case, f (M) may be added in addition to schedulingInfoSIB1-r13 of MIB-NB_DL) Is allocated to 11 spare bits of information and provided to the NB-IoT UE.

4.2. The second proposal is as follows: "use the same subframe location as in the previous case for NPSS, NSSS, and NPBCH, and change the location of SIB1-NB according to UL/DL configuration (part A)"

In this section, a detailed description will be given of a method of changing the subframe position of the SIB1-NB according to the UL/DL configuration while maintaining the NPSS, NSSS, and NPBCH structures same as the previous case, assuming that NB-IoT is not supported in UL/DL configuration 0.

However, since the subframe location of the SIB1-NB is not fixed, information about the scheduling of the SIB1-NB can be added and transmitted in the MIB-NB.

According to the method proposed in this section, the subframe locations of NPSS, NSSS, NPBCH, and SIB1-NB can be configured as shown in the following two tables. Alternatively, the SIBs 1-NB and NSSS may be sent in subframe 9 alternately every 10 milliseconds.

[ Table 11]

[ Table 12]

Here, NSSS is transmitted only in subframe 9 of an even-numbered radio frame. In this case, since UL/DL configuration 0 has only two full downlink subframes in the radio frame, it is assumed that UL/DL configuration 0 is not considered in the second proposal.

In addition, UL/DL configuration 6 has only three full downlink subframes in a radio frame. Thus, in UL/DL configuration 6, SIB1-NB may be divided into SIB1-NB-a and SIB1-NB-B and transmitted using the DwPTS of special subframes 1 and 6, SIB1-NB, or SIB1-NB may be transmitted through only one of special subframes 1 and 6. This approach may be particularly considered in NB-IoT systems according to the 3GPP NR system.

As a method of changing the scheduling of the SIB1-NB according to the UL/DL configuration and the special subframe configuration, it is necessary to change SIB1-NB scheduling information in the MIB-NB or add SIB1-NB scheduling information to the MIB-NB and transmit.

The information for SIB1-NB scheduling may be included as 4-bit information in the MIB and sent to the NB-IoT UE. The 4-bit information of the MIB may determine the number of repetitions of the SIB1-NB and the TBS, and may be transmitted by modulation through Quadrature Phase Shift Keying (QPSK).

Then, the NB-IoT UE uses 11 OFDM symbols except for the first 3 OFDM symbols in the radio frame and performs rate matching based on NB-IoT antenna port information and LTE antenna port information obtained from NPBCH detection. In particular, the NB-IoT UE may be based on SIB1-NB repetition information obtained from the MIB-NB and SIB1-NB repetition information obtained from the NSSSTo determine the location of the radio frame in which the SIB1-NB is transmitted.

The NB-IoT UE may use "a portion of 11 spare bits for NPBCH" or "CRC masking different from traditional NPBCH CRC masking" to acquire information about the subframe location of SIB 1-NB.

Here, according to the method of "using a part of 11 spare bits for NPBCH", it is possible to distinguish up to 2048 pieces of information from each other. However, since the spare bits may be used to indicate other information in the future, a minimum number of bits may be allocated to the information regarding the subframe location of the SIB 1-NB.

According to the method of "using CRC masking different from the conventional NPBCH CRC masking", the performance of CRC false alarm may be affected by the amount of added information. Therefore, there is a need to distinguish information about the SIB1-NB at a minimum level. In this case, information about the SIB1-NB can be distinguished in each case as follows.

1. Fixing the location of SIB1-NB according to UL/DL configuration

Referring to table 11, the SIB1-NB may be transmitted in (on) subframe 4 or 9 or subframe 1 or 6 (or 1 and 6). Thus, the information regarding the subframe location of the SIB1-NB may be divided into a maximum of four (or five) pieces.

2. When the position of SIB1-NB changes according to UL/DL configuration

Referring to table 12, the SIB1-NB may be transmitted in (on) subframe 3,4,6,7,8, or 1 (or subframes 1 and 6). In this case, the information on the subframe location of the SIB1-NB may be divided into a maximum of six (or seven) pieces.

3. When the position of SIB1-NB changes according to special subframe configuration

Referring to tables 11 and 12, in case of UL/DL configuration 6, NPSS, NSSS, and NPBCH are allocated to a full downlink subframe, and thus, SIB1-NB may be allocated to subframe 1 or 6 (or subframes 1 and 6), which is a special subframe.

In this case, the DwPTS period varies among the special subframe configurations. Therefore, the number of available OFDM can be limited. Furthermore, because the number of OFDM symbols in the control region is not known before the NB-IoT UE decodes the SIB1-NB, the number of OFDM symbols on which the SIB1-NB may be transmitted in addition to 3 OFDM symbols in the DwPTS period may be further reduced.

Accordingly, in order to use as many OFDM symbols as possible in the DwPTS period, the eNB may transmit information on "the number of symbols of the control region of the SIB1-NB subframe on NPBCH" to the NB-IoT UE.

In addition, there are 10 special subframe configurations for the normal CP and the type, and 8 special subframe configurations for the extended CP. However, when only information on the DwPTS period is distinguished, 6 special subframe configurations are sufficient for the normal CP and 5 special subframe configurations are sufficient for the extended CP.

In addition, if the number of downlink OFDM symbols of the DwPTS is insufficient, the downlink OFDM symbols may be further allocated in a gap period following the DwPTS to transmit the SIB 1-NB. In this case, a legacy LTE reference signal (e.g., CRS) may not be included in the downlink OFDM symbol added after the DwPTS period. As a result, the rate matching of the SIB1-NB may be applied differently from the existing DwPTS or full downlink subframe.

Alternatively, the SIBs 1-NB and NSSS may be sent in subframe 9 alternately every 10 milliseconds.

4.3. The third proposal is that: "use the same subframe location as in the previous case for NPSS, NSSS, and NPBCH, and change the location of SIB1-NB according to UL/DL configuration (part B)"

In this section, a method similar to the second proposal and even allowing the use of UL/DL configuration 0 will be described in detail.

However, the proposed method may be applied only to enbs supporting eIMTA or enbs allowing scheduling constraints on subframe 9. According, the uplink subframe 9 may be changed to a downlink subframe every 2 msec as shown in the following table.

In addition, the SIB1-NB may be divided into two parts as in UL/DL subframe configuration 6, and transmitted in subframes 1 and 6.

Alternatively, the SIB1-NB and NSSS may be alternately sent in subframe 9 every 10 milliseconds.

[ Table 13]

4.4. The fourth proposal is that: 'transmitting NPBCH in special subframe of anchor carrier'

As described above, NPBCH is transmitted by QPSK modulation, unlike NPSS and NSSS, which are composed of a combination of specific sequences, and thus NPBCH may not need to be transmitted on consecutive OFDM symbols. However, in this case, NRS for channel estimation may be transmitted in the interval of the non-consecutive OFDM symbols. Furthermore, considering that the TDD system is generally suitable for a relatively narrow coverage as compared to the FDD system, the code rate of the NPBCH may be designed to be higher than that of the NPBCH of LTE release 14 NB-IoT. In other words, in the TDD system, a new NPBCH channel structure or allocation method using a smaller number of OFDM symbols than the NPBCH of the LTE release may be considered.

[ Table 14]

Table 14 shows an example of transmitting NPSS, NSSS, and NPBCH on an anchor carrier in all UL/DL configurations. In this case, the SIB1-NB may be sent on the second anchor carrier as in the first proposal.

For all UL/DL configurations, subframes 0 and 5 are configured as full downlink subframes. Thus, NPSS and NSSS may be transmitted in subframes 0 and 5, respectively, or may be transmitted in subframe 5 and subframe 0, respectively.

NPBCH modulated and transmitted by QPSK may be divided into a part a and a part B as shown in table 13, and transmitted in subframes 1 and 6. Alternatively, the payload size of the MIB may be reduced or the code rate may be increased to transmit the NPBCH in only one of subframes 1 or 6.

In the following description, it is assumed that NPBCH is divided into part a and part B and transmitted.

In UL/DL configurations 3,4, and 5, subframe 6 is configured as a full downlink subframe. However, in order to design the NPBCH structure regardless of the UL/DL configuration, the NPBCH may be divided into the part a and the part B in the same manner even in the UL/DL configurations 3,4, and 5 as in the other UL/DL configurations.

If the NPBCH is configured to be transmitted only in subframe 6 without being divided into part a and part B in the case of UL/DL configurations 3,4 and 5, a method of "using a part of 11 spare bits for NPBCH" or "expanding a table of NPBCH CRC masks" may be used to distinguish such a configuration from NPBCH configurations for other UL/DL subframes.

To divide NPBCH into part a and part B to transmit NPBCH-a and NPBCH-B in DwPTS of a special subframe, NB-IoT UEs need information on DwPTS periods for rate matching. Thus, in a manner similar to the second proposal described above, the eNB may provide relevant information to the NB-IoT UEs by "using a portion of the 11 spare bits for NPBCH" or "extending the NPBCH CRC masked table".

Alternatively, the SIB1-NB and NSSS may be alternately sent in subframe 9 every 10 milliseconds.

4.5. The fifth proposal is that: "sending NSSS and SIB1-NB by time multiplexing"

Unlike NPSS and NPBCH, NSSS and SIB1-NB may not be sent in every radio frame. More specifically, the NSSS may be configured to transmit once every 2 milliseconds, and the SIB1-NB may be configured to transmit once every 2 milliseconds or according to a sum of repetition timesNo transmission is made within a few milliseconds.

Hereinafter, a method of time multiplexing NSSS and SIB1-NB based on radio frames will be described in detail based on the features of NSSS and SIB1-NB allowing discontinuous transmission thereof as described above.

The described time multiplexing method can be defined separately from the subframe positions of NPSS and NPBCH, and can be used even when NPSS and NPBCH are configured as shown in table 13 or 14. In this section, for simplicity, the proposed time multiplexing method will be described in more detail based on table 15, which table 15 is a modification of table 14.

[ Table 15]

In table 15, NSSS may be transmitted in subframe 5 of each odd-numbered (or even-numbered) radio frame, and the SIB1-NB may be transmitted in each even-numbered (or odd-numbered) radio frame within 160-millisecond consecutive radio frames in order to avoid collision with NSSS. Here, transmitting the SIB1-NB in a continuous period of 160 milliseconds may mean that the same SIB1-NB may be repeatedly transmitted at regular intervals within 160 milliseconds.

Here, if the number of repetitions is 16, when the condition is satisfiedThe SIB1-NB may be sent in odd numbered radio frames. In this case, if the number of repetitions is 16, the SIB1-NB may not avoid colliding with the NSSS. Considering that the TDD system is suitable for a relatively narrow bandwidth compared to the FDD system, the constraint may be configured such that 16 is not used as the number of repetitions of the SIB 1-NB.

As a more specific example, the number of repetitions according to the frame structure type as shown in the following table may be proposed. In this case, to avoid collision with the SIB1-NB, NSSS may be sent in subframe 5 of each odd-numbered radio frame.

[ Table 16]

Fig. 19 is a diagram schematically illustrating a signal transmission/reception method between a UE and a BS according to the present invention.

As shown in fig. 19, the UE receives NPSS, NSSS, etc. over a first carrier (e.g., an anchor carrier) and receives a SIB1-NB over a second carrier (e.g., a non-anchor carrier).

In this case, as shown in fig. 19, the UE may receive NPSS through the first carrier in an xth (e.g., X ═ 6) sub-time interval in each time interval, and may receive NSSS through the first carrier in a Y (e.g., Y ═ 1) sub-time interval in a corresponding time interval (e.g., nth time interval) at a period of two time intervals. Next, when the MIB-NB included in the received PBCH indicates that the SIB1-NB is transmitted through the second carrier, the UE may receive the SIB1-NB through the second carrier in a sub-time interval of Y-th (e.g., Y ═ 1) in a corresponding time interval at a period of one or more time intervals.

As a specific example, in case of transmitting the SIB1-NB at a period of one time interval, the SIB1-NB may be transmitted through the second carrier in the 1 st sub-time interval of the nth time interval and the 1 st sub-time interval of the (N +1) th time interval.

Alternatively, in case of transmitting the SIB1-NB at a period of 2 or 4 time intervals, the SIB1-NB may be transmitted through the second carrier during the Y-th sub-time interval in a time interval in which the NSSS is not transmitted.

With this configuration, the UE may receive the SIB1-NB without colliding with another signal (e.g., NSSS).

As an example applicable to the present invention, when the UE operates in the LTE TDD system, the above-mentioned one time period may correspond to one radio frame of the LTE TDD system, and one sub-time interval may correspond to one subframe of the LTE TDD system.

As another example, when the UE operates in the LTE TDD system, the LTE TDD system may not support UL/DL configuration 0 of one radio frame defined in the LTE system in order to support NB IoT operation. In this case, UL/DL configuration 0 of one radio frame may correspond to "uplink/downlink configuration 0" in table 10.

As an operation corresponding to the operation of the UE described above, the BS may transmit NPSS through the first carrier in an xth (where X is, for example, 6) sub-time interval of each time interval, and transmit NSSS through the first carrier in a yth (for example, Y ═ 1) sub-time interval of a corresponding time interval (for example, nth time interval) at a period of 2 time intervals. If the MIB-NB included in the received PBCH indicates that the SIB1-NB is transmitted on the second carrier, the BS may transmit the SIB1-NB on the second carrier in the Y-th (e.g., Y ═ 1) sub-time interval in the corresponding time interval at a period of one or more time intervals.

Since examples of the proposed method described above can also be included in an implementation of the present invention, it is clear that these examples are considered as one proposed method. Although the above methods may be implemented independently, the proposed methods may be implemented in a combined (aggregated) form of a part of the proposed methods. The rules may be defined such that the base station informs the UE of information on whether to apply the proposed method (or information on the rules of the proposed method) through a predefined signal (e.g., a physical layer signal or a higher layer signal).

5. Device configuration

Fig. 20 is a diagram illustrating configurations of a UE and a base station capable of implementing the proposed embodiments. The UE and the base station shown in fig. 20 operate to implement the above-described embodiments of the signal transmission/reception method between the UE and the base station.

UE 1 may act as a transmitter on UL and as a receiver on DL. The base station (eNB or gNB)100 may act as a receiving end on UL and as a transmitting end on DL.

That is, each of the UE and the base station may include: a transmitter (Tx)10 or 110 and a receiver (Rx)20 or 120 for controlling transmission and reception of information, data and/or messages; and an antenna 30 or 130 for transmitting and receiving information, data and/or messages.

Each of the UE and the base station may further include a processor 40 or 140 for implementing the foregoing embodiments of the present disclosure, and a memory 50 or 150 for temporarily or permanently storing the operation of the processor 40 or 140.

The UE 1 configured as described above receives NPSS, NSSS, SIB1-NB, etc. through the receiver 20. In this operation, UE 1 may receive NPSS and NSSS over a first carrier (e.g., an anchor carrier) and SIB1-NB over a second carrier (e.g., a non-anchor carrier). For example, as shown in fig. 19, if the NSSS is received in the 1 st sub-interval in the nth interval, the SIB1-NB may be received in the 1 st sub-interval in the N +1 (or N +3) th interval.

As a corresponding operation, the base station 100 transmits NPSS, NSSS, SIB1-NB, etc. through the transmitter 110. In this operation, the base station 100 may transmit NPSS and NSSS over a first carrier (e.g., an anchor carrier) and SIB1-NB over a second carrier (e.g., a non-anchor carrier). For example, as shown in fig. 19, if the NSSS is transmitted in the 1 st sub-interval in the nth interval, the SIB1-NB may be transmitted in the 1 st sub-interval in the (N +1) (or (N +3) th interval.

Tx and Rx of the UE and the base station may perform packet modulation/demodulation functions for data transmission, high-speed packet channel coding functions, OFDM packet scheduling, TDD packet scheduling, and/or channelization. Each of the UE and the base station of fig. 20 may further include a low power Radio Frequency (RF)/Intermediate Frequency (IF) module.

Meanwhile, the UE may be any one of a Personal Digital Assistant (PDA), a cellular phone, a Personal Communication Service (PCS) phone, a Global System for Mobile (GSM) phone, a Wideband Code Division Multiple Access (WCDMA) phone, a Mobile Broadband System (MBS) phone, a handheld PC, a laptop PC, a smart phone, a multi-mode multi-frequency (MM-MB) terminal, and the like.

A smart phone is a terminal that takes advantage of the advantages of both mobile phones and PDAs. It incorporates the PDA's functions (i.e., scheduling and data communications such as fax transmission and reception and internet connection) into the mobile phone. The MB-MM terminal refers to a terminal having a multi-modem chip built therein and capable of operating in any one of a mobile internet system and other mobile communication systems (e.g., CDMA2000, WCDMA, etc.).

Embodiments of the present disclosure may be implemented by various means (e.g., hardware, firmware, software, or a combination thereof).

In a hardware configuration, the method according to the exemplary embodiments of the present disclosure may be implemented by one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or the like.

In a firmware or software configuration, the method according to the embodiment of the present disclosure may be implemented in the form of a module, a procedure, a function, etc. performing the above-described functions or operations. The software codes may be stored in memory 50 or 150 and executed by processors 40 or 140. The memory is located inside or outside the processor and may transmit and receive data to and from the processor via various known means.

It will be apparent to those skilled in the art that the present disclosure may be practiced in other specific ways than those set forth herein without departing from the spirit and essential characteristics of the present disclosure. The above-described embodiments are therefore to be construed in all aspects as illustrative and not restrictive. The scope of the disclosure should be determined by the appended claims and their legal equivalents, rather than by the description, and all changes that come within the meaning and range of equivalency of the appended claims are intended to be embraced therein. It is obvious to those skilled in the art that claims that are not explicitly cited in each other in the appended claims may be presented in combination as an embodiment of the present disclosure or included as a new claim by subsequent amendment after the application is filed.

Industrial applicability

The present disclosure is applicable to various wireless access systems including a 3GPP system and/or a 3GPP2 system. In addition to these wireless access systems, embodiments of the present disclosure are applicable to all technical fields in which wireless access systems find their application. Furthermore, the proposed method can also be applied to millimeter wave communication using an ultra-high frequency band.