KR20200051096A - Apparatus and method of CQI management for group-based side-link in new radio - Google Patents

Abstract

The present invention provides a channel quality information or indicator (CQI) management method for new radio (NR) sidelink operation, which is a wireless link between terminals for providing a vehicle to everything (V2X) service in a next generation/5G wireless access network. According to an embodiment of the present invention, in a method of managing CQI in sidelink communication in a next generation wireless network, a terminal sets a terminal to perform channel state information (CSI) reporting among other terminals based on CSI of other terminals set as a group cast.

Description

Apparatus and method of CQI management for group-based side-link in new radio}

The present invention describes a CQI management method for NR sidelink operation, which is a wireless link between terminals for providing V2X service in a next generation / 5G wireless access network (hereinafter referred to as NR [New Radio] in the present invention). . In particular, a specific method for CQI estimation and HARQ procedure design between scheduling UE and scheduled UEs for Groupcast sidelink communication is described.

According to an embodiment of the present invention, in a method for managing CQI in sidelink communication in a next-generation wireless network, setting a terminal to perform CSI reporting among the other terminals based on the CSI of other terminals set as a group cast It provides a method of characterizing.

1 is a diagram briefly showing a structure of an NR wireless communication system to which the present embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which the present embodiment can be applied.
3 is a diagram for describing a resource grid supported by a radio access technology to which the present embodiment can be applied.
4 is a diagram for describing a bandwidth part supported by a radio access technology to which the present embodiment can be applied.
5 exemplarily shows a synchronization signal block in a radio access technology to which the present embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a view for explaining CORESET.
8 is a diagram illustrating an example of symbol level alignment among different SCSs.
9 is a diagram illustrating a conceptual example of a bandwidth part.
10 is a diagram showing the configuration of a base station according to another embodiment.
11 is a view showing the configuration of a user terminal according to another embodiment.

Hereinafter, some embodiments of the present technology will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, the same components may have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the technical idea, when it is determined that the detailed description of the related known configuration or function may obscure the subject matter of the technical idea, the detailed description may be omitted.

In addition, in describing components of the present embodiments, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the essence, order, order, or number of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected to or connected to the other component, but different components between each component It will be understood that the "intervenes" may be, or each component may be "connected", "coupled" or "connected" through other components.

In addition, the terms and technical names used in the present specification are for describing specific embodiments, and the technical idea is not limited to the terms. The terms described below may be interpreted as meanings generally understood by those having ordinary knowledge in the technical field to which this technical idea belongs, unless otherwise defined. When the term is an incorrect technical term that does not accurately represent the technical idea, it should be understood as being replaced by a technical term that can be correctly understood by those skilled in the art. In addition, the general terms used in this specification should be interpreted as defined in the dictionary or in context before and after, and should not be interpreted as an excessively reduced meaning.

The wireless communication system in the present specification means a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, and a core network.

The embodiments disclosed below can be applied to a wireless communication system using various wireless access technologies. For example, the present embodiments are code division multiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single-electron frequency division multiple access (SC-FDMA). It can be applied to various wireless access technologies such as. CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with radio technologies such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented with wireless technologies such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA). IEEE 802.16m is an evolution of IEEE 802.16e, and provides backward compatibility with a system based on IEEE 802.16e. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is part of evolved UMTS (E-UMTS) using evolved-UMTS terrestrial radio access (E-UTRA), adopts OFDMA in the downlink and SC- in the uplink. Adopt FDMA. As described above, the present embodiments may be applied to a currently disclosed or commercialized wireless access technology, or may be applied to a wireless access technology currently being developed or to be developed in the future.

Meanwhile, the terminal in the present specification is a comprehensive concept that refers to a device including a wireless communication module that performs communication with a base station in a wireless communication system. UEs in WCDMA, LTE, HSPA, and IMT-2020 (5G or New Radio) (User Equipment), of course, should be interpreted as a concept including all of MS (Mobile Station), User Terminal (UT), Subscriber Station (SS), and wireless device in GSM. In addition, the terminal may be a user portable device such as a smart phone depending on the type of use, and in the V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, or the like. In addition, in the case of a machine type communication system, it may mean an MTC terminal or an M2M terminal equipped with a communication module so that the machine type communication is performed.

The base station or cell herein refers to an end that communicates with a terminal in terms of a network, Node-B (Node-B), evolved Node-B (eNB), gNode-B (gNB), Low Power Node (LPN), Sector, Site, Various types of antennas, Base Transceiver System (BTS), Access Point, Point (e.g., Send Point, Receive Point, Send / Receive Point), Relay Node (Relay Node) ), Mega cell, macro cell, micro cell, pico cell, femto cell, remote radio head (RRH), radio unit (RU), and small cell (small cell).

Since the various cells listed above have a base station that controls each cell, the base station can be interpreted in two ways. 1) a device that provides a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, and a small cell in relation to the wireless area, or 2) the wireless area itself. In 1), all devices that provide a predetermined wireless area are controlled by the same entity or interact to configure the wireless area in a collaborative manner. Points, transmission / reception points, transmission points, reception points, and the like, according to a configuration method of a wireless area, are examples of a base station. In 2), the radio area itself, which receives or transmits a signal from the perspective of the user terminal or the neighboring base station, may be directed to the base station.

In this specification, a cell is a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission / reception point, or a transmission / reception point itself. Can be.

Uplink (Uplink, UL, or uplink) means a method of transmitting and receiving data to the base station by the terminal, downlink (Downlink, DL, or downlink) means a method of transmitting and receiving data to the terminal by the base station A downlink may refer to a communication or communication path from multiple transmission / reception points to a terminal, and an uplink may refer to a communication or communication path from a terminal to multiple transmission / reception points. At this time, in the downlink, the transmitter may be a part of multiple transmission / reception points, and the receiver may be a part of the terminal. In addition, in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.

In the uplink and downlink, control information is transmitted and received through control channels such as a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH), and a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), and the like. The same data channel is configured to transmit and receive data. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is also referred to as 'transmit and receive PUCCH, PUSCH, PDCCH and PDSCH'. do.

In order to clarify the description, hereinafter, the technical idea is mainly focused on the 3GPP LTE / LTE-A / NR (New RAT) communication system, but the technical features are not limited thereto.

3GPP has been conducting research on 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology after research on 4G (4th-Generation) communication technology. Specifically, 3GPP is conducting research on new NR communication technology that is separate from LTE-A pro and 4G communication technology, which have improved LTE-Advanced technology to meet the requirements of ITU-R with 5G communication technology. LTE-A pro and NR are both expected to be submitted in 5G communication technology, but hereinafter, for convenience of explanation, the present embodiments will be described with reference to NR.

The operating scenario in NR defined various operation scenarios by adding considerations for satellites, automobiles, and new verticals in the existing 4G LTE scenarios.In terms of service, it has an eMBB (Enhanced Mobile Broadband) scenario, high terminal density, but wide It is deployed in the range and supports the Massive Machine Communication (mmmTC) scenario, which requires low data rate and asynchronous connection, and the Ultra Reliability and Low Latency (URLLC) scenario, which requires high responsiveness and reliability and supports high-speed mobility. .

To satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, low latency technology, ultra-high-bandwidth (mmWave) support technology, and forward compatibility technology are applied. In particular, the NR system proposes various technical changes in terms of flexibility in order to provide forward compatibility. The main technical features will be described below with reference to the drawings.

<NR system general>

1 is a diagram briefly showing the structure of an NR system to which the present embodiment can be applied.

Referring to FIG. 1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and NG-RAN is controlled for a user plane (SDAP / PDCP / RLC / MAC / PHY) and user equipment (UE). It consists of gNB and ng-eNBs that provide a plane (RRC) protocol termination. The gNB interconnects or the gNB and ng-eNB are interconnected via an Xn interface. gNB and ng-eNB are each connected to 5GC through an NG interface. The 5GC may include an Access and Mobility Management Function (AMF), which is responsible for a control plane such as a terminal access and mobility control function, and a User Plane Function (UPF), which is a control function for user data. The NR includes support for frequencies below 6 GHz (FR1, Frequency Range 1) and frequencies above 6 GHz (FR2, Frequency Range 2).

gNB means a base station providing NR user plane and control plane protocol termination to the terminal, and ng-eNB means a base station providing E-UTRA user plane and control plane protocol termination to the terminal. The base station described in this specification should be understood as a meaning encompassing gNB and ng-eNB, and may be used in a sense to refer to a gNB or ng-eNB as necessary.

<NR wave form, pneumatics and frame structure>

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with multiple input multiple output (MIMO), and has the advantage of being able to use a low-complexity receiver with high frequency efficiency.

On the other hand, in the NR, since the demands for data rate, delay rate, and coverage for each of the three scenarios described above are different from each other, it is necessary to efficiently satisfy the requirements for each scenario through a frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

값이 2의 지수 값으로 사용되어 지수적으로 변경된다.Specifically, the NR transmission numerology is determined based on sub-carrier spacing (CP) and cyclic prefix (CP), and is based on 15khz as shown in Table 1 below.

The value is used as an exponent value of 2 and is changed exponentially.

Subcarrier spacing Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR numerology can be divided into 5 types according to the subcarrier spacing. This is different from that in which the subcarrier spacing of LTE, which is one of 4G communication technologies, is fixed at 15khz. Specifically, the subcarrier interval used for data transmission in NR is 15, 30, 60, and 120 khz, and the subcarrier interval used for synchronization signal transmission is 15, 30, 12, and 240 khz. In addition, the extended CP applies only to the 60khz subcarrier spacing. On the other hand, the frame structure (frame structure) in the NR is defined as a frame having a length of 10ms composed of 10 subframes (subframe) having the same length of 1ms. One frame can be divided into 5 ms half frames, and each half frame includes 5 subframes. In the case of a 15khz subcarrier interval, one subframe is composed of one slot, and each slot is composed of 14 OFDM symbols.

2 is a diagram for explaining a frame structure in an NR system to which the present embodiment can be applied.

Referring to FIG. 2, the slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length of the slot may vary depending on the subcarrier interval. For example, in the case of a numerology having a 15 khz subcarrier spacing, the slot is 1 ms long and is configured to have the same length as the subframe. On the contrary, in the case of a neuromerlage having a 30 khz subcarrier spacing, a slot is composed of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined with a fixed time length, and the slot is defined by the number of symbols, so that the time length may vary according to the subcarrier interval.

Meanwhile, the NR defines a basic unit of scheduling as a slot, and also introduces a mini-slot (or sub-slot or non-slot based schedule) to reduce transmission delay in a radio section. If a wide subcarrier interval is used, the length of one slot is inversely shortened, and thus transmission delay in a wireless section can be reduced. The mini-slot (or sub-slot) is for efficient support for the URLLC scenario and can be scheduled in units of 2, 4, and 7 symbols.

Also, unlike LTE, uplink and downlink resource allocation is defined as a symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of directly transmitting HARQ ACK / NACK in a transmission slot has been defined, and this slot structure is referred to as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in Rel-15. In addition, a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which downlink symbols and uplink symbols are combined are supported. In addition, NR supports that data transmissions are scheduled to be distributed in one or more slots. Accordingly, the base station can inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station may indicate the slot format by indicating the index of a table configured through RRC signaling using SFI, and dynamically indicate through DCI (Downlink Control Information) or statically or quasi-statically through RRC. It might be.

<NR Physical Resources>

With regard to physical resources in NR, antenna ports, resource grids, resource elements, resource blocks, and bandwidth parts are considered. Can be.

The antenna port is defined such that a channel carrying a symbol on the antenna port can be inferred from a channel carrying another symbol on the same antenna port. If the large-scale property of a channel carrying a symbol on one antenna port can be inferred from a channel carrying a symbol on another antenna port, the two antenna ports are QC / QCL (quasi co-located or quasi co-location). Here, a wide range of characteristics include one or more of delay spread, doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for describing a resource grid supported by a radio access technology to which the present embodiment can be applied.

Referring to FIG. 3, a resource grid may exist according to each neuromerging because the NR supports a plurality of neuromerging on the same carrier. In addition, the resource grid may exist according to the antenna port, subcarrier spacing, and transmission direction.

A resource block is composed of 12 subcarriers and is defined only on the frequency domain. In addition, the resource element (resource element) is composed of one OFDM symbol and one subcarrier. Therefore, as shown in FIG. 3, the size of one resource block may vary according to the subcarrier interval. In addition, in NR, "Point A" serving as a common reference point for the resource block grid, a common resource block, and a virtual resource block are defined.

4 is a diagram for describing a bandwidth part supported by a radio access technology to which the present embodiment can be applied.

Unlike LTE, where the carrier bandwidth is fixed at 20Mhz in NR, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in NR, as shown in FIG. 4, a terminal can be used by designating a bandwidth part within a carrier bandwidth. In addition, the bandwidth part is associated with one neurology and is composed of a subset of consecutive common resource blocks, and can be dynamically activated with time. A maximum of 4 bandwidth parts are configured in the uplink and downlink, respectively, and data is transmitted and received using the bandwidth part activated at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidth parts are independently set, and in the case of an unpaired spectrum, unnecessary frequency re-tunning is prevented between downlink and uplink operation. In order to achieve this, the bandwidth part of the downlink and uplink is set in pairs so that the center frequency can be shared.

<NR initial connection>

In NR, a terminal accesses a base station and performs a cell search and random access procedure to perform communication.

Cell search is a procedure in which a terminal synchronizes with a cell of a corresponding base station, acquires a physical layer cell ID, and acquires system information using a synchronization signal block (SSB) transmitted by the base station.

5 exemplarily shows a synchronization signal block in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 5, the SSB is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) and three OFDM symbols occupying one symbol and 127 subcarriers, respectively, and a PBCH spanning 240 subcarriers.

The UE receives the SSB by monitoring the SSB in the time and frequency domain.

SSB can be transmitted up to 64 times in 5 ms. Multiple SSBs are transmitted in different transmission beams within a 5 ms time period, and the UE performs detection by assuming that SSBs are transmitted every 20 ms periods based on a specific one beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted at 3 GHz or less, and up to 8 SSBs can be transmitted using up to 8 different beams in the frequency band from 3 to 6 GHz and up to 64 in the frequency band above 6 GHz.

Two SSBs are included in one slot, and the starting symbol and the number of repetitions in the slot are determined according to the subcarrier interval.

On the other hand, SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the SS of the conventional LTE. That is, the SSB may be transmitted out of the center of the system band, and when supporting broadband operation, a plurality of SSBs may be transmitted on the frequency domain. Accordingly, the terminal monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and the synchronization raster, which are the center frequency location information of the channel for initial access, are newly defined in the NR, and the synchronization raster has a wider frequency interval than the carrier raster, and thus supports fast SSB search of the UE. Can be.

The terminal may acquire MIB through the PBCH of the SSB. The MIB (Master Information Block) includes minimum information for the terminal to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, PBCH is information on the location of the first DM-RS symbol on the time domain, information for the UE to monitor SIB1 (for example, SIB1 neuromerging information, information related to SIB1 CORESET, search space information, PDCCH Related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like. Here, the SIB1 pneumatic information is equally applied to messages 2 and 4 of the random access procedure for accessing the base station after the terminal completes the cell search procedure.

The aforementioned RMSI means System Information Block 1 (SIB1), and SIB1 is broadcast periodically (ex, 160 ms) in a cell. SIB1 includes information necessary for the UE to perform the initial random access procedure, and is periodically transmitted through the PDSCH. In order to receive SIB1, the UE must receive pneumatic information used for SIB1 transmission and control resource set (CORESET) information used for scheduling of SIB1 through the PBCH. The UE checks scheduling information for SIB1 using SI-RNTI in CORESET, and acquires SIB1 on the PDSCH according to the scheduling information. SIBs other than SIB1 may be periodically transmitted or may be transmitted according to a terminal request.

6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6, when cell search is completed, the UE transmits a random access preamble for random access to the base station. The random access preamble is transmitted through PRACH. Specifically, the random access preamble is transmitted to the base station through PRACH composed of continuous radio resources in a specific slot that is periodically repeated. In general, a contention-based random access procedure is performed when the UE initially accesses a cell, and a non-competition-based random access procedure is performed when random access is performed for beam failure recovery (BFR).

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), UL grant (uplink radio resource), temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier) and TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, a random access preamble identifier may be included to inform which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a Random Access-Radio Network Temporary Identifier (RA-RNTI).

Upon receiving a valid random access response, the terminal processes the information included in the random access response, and performs scheduled transmission to the base station. For example, the UE applies TAC and stores a temporary C-RNTI. In addition, by using UL Grant, data stored in the buffer of the terminal or newly generated data is transmitted to the base station. In this case, information capable of identifying the terminal should be included.

Finally, the terminal receives a downlink message for contention resolution.

<NR CORESET>

The downlink control channel in the NR is transmitted in a control resource set (CORESET) having a length of 1 to 3 symbols, and transmits up / down scheduling information, slot format index (SFI), and transmit power control (TPC) information. .

Thus, in order to secure the flexibility of the system, NR introduced the concept of CORESET. CORESET (Control Resource Set) means a time-frequency resource for a downlink control signal. The UE may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. QCL (Quasi CoLocation) assumptions for each CORESET were established, and this is used to inform the characteristics of the analog beam direction in addition to delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by the conventional QCL.

7 is a view for explaining CORESET.

Referring to FIG. 7, CORESET may exist in various forms within a carrier bandwidth within one slot, and CORESET may consist of up to 3 OFDM symbols in a time domain. In addition, CORESET is defined as a multiple of 6 resource blocks from the frequency domain to the carrier bandwidth.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration to receive additional configuration information and system information from the network. After establishing a connection with the base station, the terminal may receive and configure one or more CORESET information through RRC signaling.

In this specification, frequency, frame, subframe, resource, resource block, region, band, subband, control channel, data channel, synchronization signal, various reference signals, various signals, various messages related to NR (New Radio) Can be interpreted as meaning used in the past or present or various meanings used in the future.

 [5G NR (New Rat)]

3GPP recently approved “Study on New Radio Access Technology”, a study item for research on next-generation / 5G radio access technology, and based on this, RAN WG1 has a frame structure, channel coding & modulation for NR (New Radio), respectively. , waveform & multiple access scheme, etc. started. NR is required to be designed to satisfy various QoS requirements required for each segmented and specific usage scenario, as well as an improved data rate compared to LTE. In particular, as a representative usage scenario of NR, enhancement mobile BroadBand (eMBB), massive MTC (mMTC) and Ultra Reliable and Low Latency Communications (URLLC) have been defined, and a flexible frame compared to LTE as a method to satisfy the requirements for each usage scenario. Structure design is required. Because each usage scenario has different requirements for data rates, latency, reliability, coverage, etc., different numerology (as a method for efficiently satisfying requirements for each usage scenario through a frequency band constituting an arbitrary NR system) For example, there is a need for a method of efficiently multiplexing radio resource units based on subcarrier spacing, subframe, TTI, etc.).

As a method for this, a method of multiplexing and supporting scheduling units in a time domain and TDM, FDM, or TDM / FDM based on one or multiple NR component carriers for numerology having different subcarrier spacing values Discussion on how to support more than one time unit in the construction was made. In this regard, in NR, a subframe is defined as a type of time domain structure, and 14 OFDM symbols of normal CP overhead based on 15kHz SCS (Sub-Carrier Spacing), which is the same as LTE as a reference numerology for defining the subframe duration. It was decided to define a single subframe duration consisting of. Accordingly, the subframe in NR has a time duration of 1 ms. However, unlike LTE, the subframe of NR is an absolute reference time duration, and slots and mini-slots may be defined as time units based on actual uplink / downlink data scheduling. In this case, the number of OFDM symbols constituting the slot and the y value are defined as y = 7 and 14 for numerology having an SCS value of up to 60 kHz, and y = 14 for numerology having an SCS value greater than 60 kHz. It was decided to have a value.

Accordingly, an arbitrary slot may be composed of 7 or 14 symbols, and all symbols may be used for DL transmission, or all symbols may be used for UL transmission, or DL portion depending on the transmission direction of the slot. + (gap) + UL portion.

In addition, in a certain numerology (or SCS), a mini-slot consisting of fewer symbols than the corresponding slot is defined, and based on this, a short length time-domain scheduling interval for transmitting / receiving uplink / downlink data is established, or slot aggregation Through this, a long-length time-domain scheduling interval for transmitting / receiving uplink / downlink data may be configured. In particular, in the case of transmission / reception of latency critical data such as URLLC, when scheduling is performed in a slot unit based on 0.5 ms (7 symbols) or 1 ms (14 symbols) defined in a numerology-based frame structure having a small SCS value such as 15 kHz. In order to achieve this, it may be difficult to satisfy the latency requirement, so for this, a mini-slot consisting of fewer OFDM symbols than the corresponding slot can be defined to define scheduling for latency critical data such as the corresponding URLLC.

Alternatively, as described above, by supporting multiplexing of numerology with different SCS values in one NR carrier by TDM and / or FDM method, based on the slot (or mini-slot) length defined for each numerology. A method of scheduling data according to latency requirements is also being considered. For example, as shown in FIG. 8 below, when the SCS is 60 kHz, since the symbol length is reduced to about 1/4 compared to the case of the SCS 15 kHz, when one slot is composed of 7 OFDM symbols in the same way, the corresponding 15 kHz based slot The length is 0.5ms, while the slot length based on 60kHz is reduced to about 0.125ms.

In this way, NR defines different SCS or different TTI lengths to discuss how to satisfy URLLC and eMBB requirements.

[BWP (bandwidth part)]

In the case of the existing LTE system, it supports scalable bandwidth operation for any LTE component carrier (CC). That is, according to the frequency deployment scenario, any LTE operator can configure a single LTE CC to configure a minimum bandwidth of 1.4 MHz to a maximum of 20 MHz, and the normal LTE terminal has a 20 MHz bandwidth of one LTE CC. Transceiver capability was supported.

However, in the case of NR, the design is made to support NR terminals having different transmission / reception bandwidth capabilities through one wideband NR CC, and thus is subdivided into arbitrary NR CCs as shown in FIG. 9 below. It is required to support flexible wider bandwidth operation through different bandwidth part configuration and activation for each terminal by configuring one or more bandwidth part (s) composed of the configured bandwidth.

Specifically, in the NR, one or more bandwidth parts can be configured through one serving cell configured from the viewpoint of the terminal, and the corresponding terminal activates one DL bandwidth part and one UL bandwidth part in the serving cell, thereby uplink / downlink data. It is defined to be used for transmission and reception. In addition, when a plurality of serving cells are configured in the corresponding terminal, that is, for a terminal to which CA is applied, one DL bandwidth part and / or UL bandwidth part is activated for each serving cell, and uplink / downlink is performed using radio resources of the corresponding serving cell. It is defined to be used for transmitting and receiving link data.

Specifically, an initial bandwidth part for an initial access procedure of a terminal is defined in an arbitrary serving cell, and one or more UE-specific bandwidth part (s) is configured through dedicated RRC signaling for each terminal, and also fallback for each terminal The default bandwidth part for operation can be defined.

However, it can be defined to activate and use a plurality of DL and / or UL bandwidth parts at the same time according to the capability and bandwidth part (s) configuration of the terminal in any serving cell, but in NR rel-15, any terminal can use It was defined to activate and use only one DL bandwidth part and UL bandwidth part at a time.

[LTE sidelink]

In the existing LTE system, a direct channel between terminals to provide direct communication between terminals and V2X (especially V2V) service, that is, design of a radio channel and radio protocol for sidelink transmission / reception. In this regard, a PSSS / SSSS that is a synchronization signal for synchronization between a wireless sidelink transmitting end and a receiving end and a PSBCH (Physical Sidelink Broadcasting Channel) for transmitting and receiving a sidelink Master Information Block (MIB) have been defined, and PSDCH for transmitting and receiving discovery information. (Physical Sidelink Discovery channel), PSCCH (Physical Sidelink Control Channel) for transmitting and receiving Sidelink Control Information (SCI), and PSSCH (Physical Sidelink Shared Channel) for transmitting and receiving sidelink data were made.

In the existing V2X sidelink, only broadcast-related transmission existed. In 5G NR V2X, Groupcast and unicast are newly introduced as new technologies. Therefore, the transmission link management method for Groupcast / Unicast transmission is currently being discussed in Rel-16.

The present invention describes a CQI management method for NR sidelink operation, which is a wireless link between terminals for providing a next generation / 5G NR V2X service. In particular, a specific method for CQI estimation and HARQ procedure design between scheduling UE and scheduled UEs for Groupcast sidelink communication is described.

Currently, NR V2X is undergoing a new sidelink design. That is, it was decided to introduce a new Unicast / Groupcast in addition to the broadcast supported by the existing LTE sidelink.

In addition, Groupcast also decided to support sidelink HARQ feedback like Unicast.

Below are the relevant decisions at the RAN1 # 94bis meeting.

Agreements:

· For unicast, sidelink HARQ feedback and HARQ combining in the physical layer are supported.

o FFS details, including the possibility of disabling HARQ in some scenarios

· For groupcast, sidelink HARQ feedback and HARQ combining in the physical layer are supported.

o FFS details, including the possibility of disabling HARQ in some scenarios

Hereinafter, a method for managing CQI related to V2X sidelink Groupcast described above is proposed. The proposal of the present invention broadly includes two categories. Includes proposals for 'CSI estimation and reporting method' and 'HARQ feedback transmission method' of scheduled UEs configured with Groupcast.

Method 1. Scheduling UE may be set to perform CSI reporting by selecting only a specific UE (s) based on CSI of scheduled UEs configured as Groupcast.

In this proposal, we propose a method for managing a radio link for Scheduling UE and Scheduled UE for Group-cast during sidelink communication of V2X.

* Scheduling UE: means a terminal that performs the same role as an existing gNB in a sidelink set as an entire group

* Scheduled UE (s): Other UEs in the group controlled by the Scheduling UE are called Scheduled UEs

In this proposal, CSI estimation and feedback methods of terminals configured as Groupcast are described. CSI (channel state information) basically refers to information such as CQI, RI, and PMI required to set the MCS of the terminal. Hereinafter, it will be described mainly on channel quality information or indicator (CQI), but for all CSI components Common application is possible.

Groupcast refers to a sidelink use-case in which a scheduling UE transmits data to terminals in a group, and it is decided to introduce HARQ feedback unlike the existing LTE V2X sidelink. Therefore, for HARQ feedback, it is basically necessary to report CQI from scheduled UEs in a group and set the MCS level of a data channel to be transmitted based on the information. In addition, since transmission may not be properly performed through this transmission process, HARQ feedback must be operated, and scheduled UEs must report A / N feedback to the scheduling UE.

In this proposal, it is suggested that all scheduled UEs in the group always feedback the CQI as a system burden, and select a specific UE among scheduled UEs to set as a representative UE in the group. The UE configured as the representative UE periodically performs CQI reporting to the scheduling UE, and other UEs do not skip or set the CQI reporting procedure. That is, UEs not set as the representative UE (s) in the group may perform CQI estimation, but may perform an operation of omitting reporting.

The UEs configured in the groupcast transmission mode report the CQI to the first scheduling UE. Here, the method of setting the representative UE by the scheduling UE can be set based on the information received as follows.

- Groupcast_RSRP: Received signal received power estimated by scheduled UEs based on PSDCH (Physical sidelink discovery channel), discovery reference signal (DRS), beacon signal, SSB, and CSI-RS transmitted by scheduling UE

- Groupcast_RSRQ: Received signal received quality estimated using the same physical RS / Channel as Groupcast_RSRP

- Groupcast_CQI: Feedback information based on MCS level estimated using the same RS as Groupcast_RSRP. RI and PMI can be transmitted together.

The Scheduling UE selects a representative UE in the group based on the feedback information, and can set the MCS level of the data channel transmitted through the PSSCH based on the CQI of the corresponding terminal. The representative UE in the group may be configured with a single terminal or some multiple terminals.

Example 1-1. Select the worst CQI UE in the group and set up the MCS to report the CQI periodically

- This is a case where the UE with the lowest CQI in the group is set as the representative UE. That is, since the data set with the MCS level around the representative UE is transmitted through the PSSCH, it can be assumed that other UEs in the group can stably receive data. This embodiment has the same concept as the cell-edge terminal of the existing cell.

Example 1-2. Worst in group, 2 ^nd  Selecting worst CQI UE and setting up MCS to report CQI periodically

-This is a case where at least two UEs having the lowest CQI in the group are selected and set as representative UEs. Final MCS level may be operated by selecting the average or 2 ^nd worst CQI of the two terminals.

Example 1-3. Selecting the best CQI UE in the group, periodically setting up the MCS and reporting the CQI

- This is a case where the UE with the highest CQI in the group is set as the representative UE. That is, only the representative UE can receive stable PSSCH only by initial transmission, and retransmission may be required to other UEs. In actual application, some offset can be used based on the value. CQI_reported (CQI reported by the terminal)-CQI_offset (adjusted value) can be adjusted to be flexible.

Example 1-4. Group's best, 2 ^nd  Selecting the best CQI UE and setting the MCS to report the CQI periodically

- It is similar to Example 1-2.

Example 1-5. Selecting the UE that represents the average CQI of the UEs in the group, periodically setting the MCS and reporting the CQI

- The MCS is selected based on the CQI average of the terminals in the group. Basically, UEs having a low CQI may require retransmission.

In all of the above embodiments, a constant CQI offset value can be applied in common. When signaling the CQI and MCS adjustment values to scheduled UEs, the UE reports the adjusted CQI by applying the corresponding values, and when not signaling to the scheduled UEs, the scheduling UE can apply and adjust itself.

In this proposal, CQI reporting for a representative UE can be set / directed by a scheduling UE through separate signaling, and can be applied in all forms such as configured siganlling / dynamic signaling.

Method 2. Scheduling UE may select only a specific UE (s) among scheduled UEs configured as a Groupcast to operate the HARQ procedure.

In this proposal, a method of operating HARQ feedback of terminals configured as a group-cast is described. According to the method of setting A / N resource of scheduled UEs in this proposal, it is described by dividing into methods 2-1 and 2-2 below. Here, the channels through which the scheduled UEs receiving data through the PSSCH report A / N feedback are specified as Sidelink_feedback channels, and the corresponding names are PSCCH format-2, Physical sidelink feedback channel (PSFCH), and Physical sidelink HARQ Indication channel (PSHICH). ) And other names, but have the same meaning.

In this proposal, the Scheduling UE can select a representative UE from among scheduled UEs in the group and set the UE to perform A / N feedback. Through this, the system burden for all UEs in the group to transmit A / N feedback may be reduced. That is, only the representative UE among the terminals receiving the data through the PSSCH normally transmits A / N feedback.

The A / N transmission method of the scheduled UE transmitting A / N can be divided into three types as follows.

- Alt.1: The terminal selected as the representative in the group feeds back the A / N for the PSSCH at any time to the scheduling UE.

- Alt.2: The terminal selected as the representative in the group feeds back Ack or Nack to the scheduling UE.

- Alt.3: The terminal selected as the representative in the group feeds back only one of Ack or Nack to the scheduling UE.

■ The representative terminal feeds back only when a Nack occurs, and skips A / N transmission when Ack occurs. The Scheduling UE detects whether or not the Nack has been received from the representative UE, and re-transmits when the Nack is detected within a predetermined A / N timing or A / N reception window. If the Nack is not detected in the reception window, it is assumed that the UE receives PSSCH successfully.

■  The representative terminal feedbacks only when an Ack occurs, and skips A / N transmission in the case of a Nack. The Scheduling UE detects whether or not the Ack is received from the representative UE, and retransmits when the Ack is not detected within a predetermined A / N timing or A / N reception window. If the Ack is not detected in the reception window, it is assumed that the PSSCH reception of the terminals has failed, and the retransmission procedure is performed.

■ The Ack or Nack transmitted by the representative UE in the Groupcast can be determined by the scheduling UE to determine whether or not it is accurately received only at the specified A / N timing, and it can also determine whether to detect it within the schedule A / N reception window. Scheduling UE or gNB may set the A / N transmission timing of other UEs in the groupcast through PSCCH, or may be set to RRC (gNB is the subject) / configured (scheduling UE is the subject). The A / N tming can be set to a common value for terminals in the group, and the principle can be applied to unicast.

Option 2-1. The Scheduling UE configures A / N resources (PSCCH) of all UEs in the Groupcast, and then configures only a specific UE (s) to perform HARQ operation.

This proposal proposes a specific method for HARQ resource setting of all terminals in a group except for the scheduling UE among HARQ feedback operation methods of terminals set as Group-cast proposed in Method 2. In this proposal, all terminals configured as a groupcast are allocated A / N resources corresponding to the PSSCH when they are received. Here, the corresponding A / N feedback resources may be independent of each other or may be set as overlapping common resources.

According to this proposal, A / N feedback resources are first set for all terminals in the groupcast. The subject of resource setting may be directly performed by the scheduling UE assigned with the resource pool or directly by the gNB. After the A / N feedback resource setting is completed, when the terminals in the groupcast receive data through the PSSCH, only the UE configured as the representative UE performs A / N feedback. The representative UE can be configured as a single UE or multiple UEs in a group as described above. That is, the A / N feedback resource setting is set for all scheduled UEs in the group, but the actual A / N feedback can be seen that only the resources of the representative UE (s) are 'activation'.

That is, A / N feedback resources are allocated even if other terminals in the groupcast except the representative UE (s) receive data through the PSSCH, but do not perform the HARQ operation.

Option 2-2. The Scheduling UE selects only a specific UE (s) in the Groupcast to set A / N resources (PSCCH) and performs HARQ operation.

In this proposal, only the representative UE (s) among the terminals configured as Groupcast are allocated A / N resources, unlike the method proposed in Method 2-1. Here, the corresponding resources may be set to be independent resources from each other or to overlap common resources.

The subject of resource setting may be directly performed by the scheduling UE assigned with the resource pool or directly by the gNB. After the single or several A / N feedback resource settings for the representative UE (s) are completed, when the terminals in the groupcast receive data through the PSSCH, only the terminal set as the representative UE performs A / N feedback. The representative UE can be configured as a single UE or multiple UEs in a group as described above.

That is, other terminals in the groupcast except the representative UE (s) do not perform HARQ operation even when receiving data through the PSSCH, and the A / N feedback resource itself is not allocated.

In Scheme 2 / 2-1 / 2-2, the HARQ procedure for the representative UE and A / N resource allocation can be set / instructed by the scheduling UE through separate signaling, and applied in all forms such as configured siganlling / dynamic signaling. This is possible.

The present invention describes a CQI management method for NR sidelink operation, which is a wireless link between terminals for providing a next generation / 5G NR V2X service. In particular, a specific method for CQI estimation and HARQ procedure design between scheduling UE and scheduled UEs for Groupcast sidelink communication is described.

10 is a diagram showing the configuration of a base station 1000 according to another embodiment.

Referring to FIG. 10, the base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The control unit 1010 controls the overall operation of the base station 1000 according to a method of managing CQI in sidelink communication in a next-generation wireless network required to perform the present invention.

The transmitting unit 1020 and the receiving unit 1030 are used to transmit and receive signals, messages, and data necessary to perform the present invention described above.

11 is a diagram showing the configuration of a user terminal 1100 according to another embodiment.

Referring to FIG. 11, the user terminal 1100 according to another embodiment includes a reception unit 1110, a control unit 1120, and a transmission unit 1130.

The reception unit 1110 receives downlink control information, data, and messages from a base station through a corresponding channel.

In addition, the control unit 1120 controls the overall operation of the user terminal 1100 according to a method for managing CQI in sidelink communication in a next-generation wireless network required to perform the present invention.

The transmitter 1130 transmits uplink control information, data, and a message to the base station through a corresponding channel.

The above-described embodiments can be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. That is, steps, components, and parts that are not described in order to clearly reveal the technical idea among the embodiments may be supported by the above-described standard documents. In addition, all terms disclosed in this specification may be described by standard documents disclosed above.

The above-described embodiments may be implemented through various means. For example, the embodiments can be implemented by hardware, firmware, software, or a combination thereof.

For implementation by hardware, the method according to the embodiments includes one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, the method according to the embodiments may be implemented in the form of an apparatus, procedure, or function that performs the functions or operations described above. The software code can be stored in a memory unit and driven by a processor. The memory unit is located inside or outside the processor, and can exchange data with the processor by various known means.

In addition, the terms "system", "processor", "controller", "component", "module", "interface", "model" and "unit" described above generally refer to computer-related entity hardware, hardware and software. It can mean a combination, software or running software. For example, the above-described components may be, but are not limited to, a processor driven process, a processor, a controller, a control processor, an object, an execution thread, a program, and / or a computer. For example, both an application running on a controller or processor and a controller or processor can be a component. One or more components can be in a process and / or thread of execution, and the components can be located on one system or deployed to more than one system.

The above description and the accompanying drawings are merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art may combine, separate, and replace configurations without departing from the essential characteristics of the present technology. Various modifications and variations such as changes will be possible. Therefore, the embodiments disclosed in the present specification are not intended to limit the technical spirit, but to explain, and the scope of the technical spirit is not limited by these embodiments. The scope of protection of the technical spirit should be interpreted by the claims, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present specification.

Claims (1)

A method for managing CQI in sidelink communication in a next generation wireless network,
Method for setting a terminal to perform CSI reporting among the other terminals, based on the CSI of the other terminals set by the group cast.

Images