CN118020364A

CN118020364A - Method for performing side link communication and apparatus therefor

Info

Publication number: CN118020364A
Application number: CN202280065575.4A
Authority: CN
Inventors: 金善禹; 徐炯旭; 李柱贤; 金泽润
Original assignee: Industry University Cooperation Foundation IUCF HYU
Current assignee: Industry University Cooperation Foundation IUCF HYU
Priority date: 2021-09-27
Filing date: 2022-09-27
Publication date: 2024-05-10

Abstract

The present disclosure relates to a method and apparatus for performing side link communication. A method and apparatus for a terminal to perform side link communication are provided, the method including the steps of: transmitting side link control information to another terminal, the side link control information including request information for requesting coordination information and indication information for indicating a resource type to be included in the coordination information; receiving the coordination information from the other terminal; and determining resources for performing side link communication based on the coordination information and/or the resource sensing information.

Description

Method for performing side link communication and apparatus therefor

Technical Field

The present disclosure relates to a technique for performing side link communication.

Background

There is a need in vehicles and industrial sites for high-capacity data processing, high-rate data processing, and various services using wireless terminals. As described above, in addition to simple voice-oriented services, there is a need for a technology for a high-rate, high-capacity communication system that is capable of handling various scenarios and large-capacity data, such as video, wireless data, and machine-type communication data.

To this end, ITU-R discloses requirements for adopting the international standard of IMT-2020, and next generation wireless communication technologies are being studied to meet the requirements of IMT-2020.

In particular, 3GPP is concurrently researching advanced LTE Pro Rel-15/16 standard and new air interface access technology (NR) standard to meet the requirement of IMT-2020, which is called 5G technology, and planning approval of both standards as next generation wireless communication technology.

The 5G technology may be applied to an autonomous car. For this reason, it is necessary to apply the 5G technology to vehicle-to-everything (V2X) communication, and the automatic driving requires high-rate transmission and reception while ensuring high reliability of the growth data.

Further, in order to satisfy driving scenarios of various autonomous vehicles, such as formation travel (platooning), it is necessary to ensure multicast data transmission/reception and unicast data transmission/reception using V2X communication.

In this way, when a plurality of terminals perform side link communication using various communication types, there is a risk of collision of radio resources for side link communication. In particular, for a communication mode in which the base station does not explicitly schedule radio resources, the risk of collision increases due to congestion of radio resources for side link communication.

Disclosure of Invention

Technical problem

The embodiment can provide a method and equipment for executing side link communication.

Technical proposal

In one aspect, the present embodiment provides a method for performing side link communication by a UE, including: transmitting side link control information to a second UE, the side link control information including request information for requesting coordination information and indication information indicating a resource type to be included in the coordination information; receiving the coordination information from the second UE; resources for performing the side-link communication are determined based on at least one of the coordination information and resource sensing information.

On the other hand, the present embodiment provides a UE that performs side link communication, including: a transmitter that transmits side link control information to a second UE, the side link control information including request information for requesting coordination information and indication information indicating a resource type to be included in the coordination information; a receiver that receives the coordination information from the second UE; and a controller determining a resource for performing the side-link communication based on at least one of the coordination information and resource sensing information.

Advantageous effects

According to the present embodiment, a method and apparatus for performing side link communication may be provided.

Drawings

Fig. 1 is a schematic diagram of the structure of an NR wireless communication system to which the present embodiment can be applied;

Fig. 2 is a schematic diagram of a frame structure in an NR system to which the present embodiment can be applied;

fig. 3 is a schematic diagram of a resource grid supported by a radio access technology to which the present embodiment can be applied;

Fig. 4 is a schematic diagram of a bandwidth part (bandwidth part) supported by a radio access technology to which the present embodiment can be applied;

Fig. 5 is an exemplary diagram of a synchronization signal block in a radio access technology to which the present embodiment can be applied;

fig. 6 is a schematic diagram of a random access procedure in a radio access technology to which the present embodiment can be applied.

Fig. 7 is a schematic diagram of CORESET.

Fig. 8 is a schematic diagram of various scenarios of V2X communication.

Fig. 9 is a schematic diagram of a communication operation using coordination information according to an embodiment.

Fig. 10 is a view for describing an operation of a UE according to an embodiment.

Fig. 11 is a view for describing a configuration of a UE according to an embodiment.

Detailed Description

Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. Where reference numerals are assigned to components of each drawing, the same components may be assigned the same numerals even though they are shown in different drawings. Details of known techniques or functions may be omitted when it may be determined that they would obscure the subject matter of the present disclosure. When the terms "comprises" and/or "comprising," "having," "including," and/or "containing" are used in this specification, they specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but does not preclude the presence or addition of one or more other features, areas, integers, steps, operations, elements, components and/or groups thereof. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The designations of "first", "second", "a", "B", "a", and "(B)" etc. may be used to describe components of the invention. These designations are provided merely to distinguish one element from another and the nature, order, or number of elements is not limited by the designation.

When two or more components are described as being "connected," "coupled," or "coupled," in describing the positional relationship between the components, the two or more components may be directly "connected," "coupled," or another component may intervene. Here, other components may be included in one or more of two or more components that are "connected," "coupled," or "coupled" to each other.

When terms such as "after," "next," "after," and "before" are used to describe time-flow relationships with respect to components, methods of operation, and methods of manufacture, it may include non-continuous relationships unless the terms "immediately" or "directly" are used.

When a component is assigned a value or its corresponding information (e.g., level), the value or corresponding information may be interpreted to include tolerances that may result from various factors (e.g., process factors, internal or external influences, or noise).

In the present disclosure, a "wireless communication system" refers to a system for providing various communication services (such as voice and data packets) using radio resources, and the system may include a UE, a base station, or a core network.

The present embodiment disclosed below can be applied to a wireless communication system using various wireless access technologies. For example, the present embodiment can be applied to various wireless access technologies such as code division multiple access (code division multiple access, CDMA), frequency division multiple access (frequency division multiple access, FDMA), time division multiple access (time division multiple access, TDMA), orthogonal frequency division multiple access (orthogonal frequency division multiple access, OFDMA), single carrier frequency division multiple access (SINGLE CARRIER frequency division multiple access, SC-FDMA) or non-orthogonal multiple access (non-orthogonal multiple access, NOMA). Further, the radio access technology may refer not only to a specific access technology but also to each generation of communication technologies established by various communication organizations (e.g., 3GPP2, wi-Fi, bluetooth, IEEE, and ITU). For example, CDMA may be implemented as a wireless technology, such as universal terrestrial radio access (universal terrestrial radio access, UTRA) or CDMA2000.TDMA may be implemented as GSM (global system for mobile communications)/GPRS (general packet radio service)/EDGE (enhanced data rates for GSM evolution). OFDMA may be implemented using wireless technology, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), and so forth. IEEE 802.16m is an evolution of IEEE 802.16e that provides backward compatibility with IEEE 802.16 e-based systems. UTRA is a part of UMTS (universal mobile telecommunications system). 3GPP (third Generation partnership project) LTE (Long term evolution) is a part of E-UMTS (evolved UMTS) that uses evolved UMTS terrestrial radio Access (E-UTRA), with the downlink employing OFDMA and the uplink employing SC-FDMA. Thus, the present embodiment can be applied to a currently disclosed or commercialized radio access technology, and can also be applied to a radio access technology currently under development or to be developed in the future.

Meanwhile, in the present disclosure, "UE" is an integrated concept meaning a device including a wireless communication module that communicates with a base station in a wireless communication system, and should be interpreted as a concept of: it may include not only User Equipment (UE) in, for example WCDMA, LTE, NR, HSPA and IMT-2020 (5G or new air interface), but also Mobile Station (MS), user Terminal (UT), subscriber station (subscriber station, SS) or wireless device in GSM. Further, depending on the type of use, the UE may be a user portable device, such as a smart phone, and in the V2X communication system, the UE may refer to a vehicle or a device in the vehicle including a wireless communication module. Further, in the case of a machine type communication system, the UE may be an MTC terminal, an M2M terminal, or URLLC terminal assigned with a communication module to perform machine type communication.

In the present disclosure, a "base station" or "cell" refers to a terminal that communicates with UEs in terms of a network, and conceptually includes various coverage areas, such as a node B, an evolved node B (eNB), gNode-B (gNB), a Low Power Node (LPN), a sector, a site, various types of antennas, a Base Transceiver System (BTS), an access point, a point (e.g., a transmission point, a reception point, or a transmission/reception point), a relay node, a macrocell, a microcell, a picocell, a femtocell, a radio remote head (remote radio head, RRH), a Radio Unit (RU), or a small cell. Further, a "cell" may refer to a cell including a bandwidth part (BWP) in a frequency domain. For example, "serving cell" may refer to an active BWP of the UE.

Since there are base stations controlling one or more cells among the various cells listed above, the base stations can be interpreted as two meanings. The base station may be 1) the device itself that provides the macro, micro, pico, femto or small cells associated with the radio area, or 2) the radio area itself. In 1), all devices providing a predetermined radio area and controlled by the same entity or interacting via cooperation to configure the radio area are denoted as base stations. An embodiment of the base station is a transmission/reception point, a transmission point or a reception point according to a scheme of configuring a radio area. In 2), the radio region in which signal reception or transmission is performed may itself be a base station from the viewpoint of the UE or the neighboring base station.

In the present disclosure, a "cell" may refer to a coverage of a signal transmitted from a transmission/reception point, a component carrier having a signal coverage transmitted from a transmission/reception point (transmission point or transmission/reception point), or the transmission/reception point itself.

Uplink (UL) refers to a scheme in which a UE transmits and receives data to and from a base station, and Downlink (DL) refers to a scheme in which a base station transmits and receives data to and from a UE. The downlink may refer to communication or communication paths from multiple transmission/reception points to the UE, and the uplink may refer to communication or communication paths from the UE to multiple transmission/reception points. In this case, in the downlink, the transmitter may be part of a plurality of transmission/reception points, and the receiver may be part of the UE. Further, in the uplink, the transmitter may be a part of the UE and the receiver may be a part of a plurality of transmission/reception points.

Uplink and downlink transmit/receive control information through a control channel such as a physical downlink control channel (physical downlink control channel, PDCCH) or a physical uplink control channel (physical uplink control channel, PUCCH), and a data channel such as a physical downlink shared channel (physical downlink SHARED CHANNEL, PDSCH) or an actual uplink shared channel (physical uplink SHARED CHANNEL, PUSCH) is configured to transmit/receive data. Hereinafter, the context of transmitting/receiving signals through channels such as PUCCH, PUSCH, PDCCH and PDSCH is denoted as "transmitting or receiving PUCCH, PUSCH, PDCCH and PDSCH".

Although the technical spirit is mainly focused on a 3GPP LTE/LTE-a/New RAT (NR) communication system for clarity of description, technical features are not limited to such a communication system.

After the 3GPP has studied the fourth generation (4G) communication technology, the fifth generation (5G) communication technology has been developed to meet the requirements of the ITU-R next generation radio access technology. In particular, 3GPP has developed novel NR communication technologies separate from LTE-A pro and 4G communication technologies, which enhance advanced LTE technology to meet ITU-R requirements as 5G communication technologies. LTE-Apro and NR both refer to 5G communication technologies. Hereinafter, unless specified as a specific communication technology, a 5G communication technology will be described with emphasis on NR.

The operation scenario in NR defines various operation scenarios by adding satellite, car and new vertical domain considerations in the existing 4G LTE scenario, and from the service perspective, supports an enhanced mobile broadband (enhanced mobile broadband, eMBB) scenario, a large-scale machine communication (mMTC) scenario with high UE density but wide deployment range requiring low data rate and asynchronous access, and an ultra-reliable low-latency (ultra-reliability and low latency, URLLC) scenario requiring high responsiveness and reliability and supporting high-speed mobility.

To meet these scenes, NR discloses a wireless communication system employing a new waveform and frame structure technique, a low delay technique, an ultra high band (mmWave) support technique, and a technique providing forward compatibility. In particular, NR systems have proposed various technical modifications in terms of flexibility in providing forward compatibility. The main technical features of NR are described below with reference to the drawings.

< NR System overview >

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

Referring to fig. 1, the NR system is divided into a 5G core network (5 GC) and an NR-RAN part. The NG-RAN is composed of a gNB and a NG-eNB, providing user plane (SDAP/PDCP/RLC/MAC/PHY) and User Equipment (UE) control plane (RRC) protocol termination. The gNB or gNB and the ng-eNB are interconnected by an Xn interface. The gNB and NG-eNB are connected to the 5GC via an NG interface. The 5GC may include access and mobility management functions (ACCESS AND mobility management function, AMF) responsible for control plane, e.g., UE access and mobility control functions, and user plane functions (user plane function, UPF) responsible for user data control functions. NR supports both a frequency band below 6GHz (frequency range 1 (FR 1)) and a frequency band above 6GHz (frequency range 2 (FR 2)).

GNB refers to a base station providing NR user plane and control plane protocol termination to a UE, while ng-eNB refers to a base station providing E-UTRA user plane and control plane protocol termination to a UE. In this disclosure, a base station should be understood to include a gNB and a ng-eNB, and is used to refer to a gNB or a ng-eNB, respectively, if necessary.

< NR waveform, parameter set (numerology), and frame Structure >

NR uses CP-OFDM waveform using cyclic prefix for downlink transmission and CP-OFDM or DFT-s-OFDM for uplink transmission. OFDM technology is easily combined with multiple-input multiple-output (multiple input multiple output, MIMO) and has the advantages of high frequency efficiency and the ability to use low complexity receivers.

Meanwhile, since the above three scenes have different requirements for data rate, delay, and coverage in NR, it is necessary to effectively satisfy the requirements of each scene by constructing a frequency band of any NR system. For this reason, techniques for efficiently multiplexing radio resources based on a plurality of different parameter sets have been proposed.

Specifically, the NR transmission parameter set is determined based on the subcarrier spacing and the Cyclic Prefix (CP), as shown in table 1 below, and it varies exponentially, with an exponent value of 2 used as μ with respect to 15 kHz.

TABLE 1

μ	Subcarrier spacing	Cyclic prefix	Supporting data	Supporting synchronization
					0	15	Ordinary use	Is that	Is that
1	30	Ordinary use	Is that	Is that
					2	60	General, extension	Is that	Whether or not
3	120	Ordinary use	Is that	Is that
					4	240	Ordinary use	Whether or not	Is that

As shown in table 1 above, NR parameter sets can be classified into five types according to subcarrier spacing. This is different from the subcarrier spacing fixed to 15kHz in LTE, which is one 4G communication technology. Specifically, in NR, the subcarrier intervals for data transmission are 15khz, 30khz, 60khz and 120khz, and the subcarrier intervals for synchronization signal transmission are 15khz, 30khz, 12khz and 240khz. Further, the extended CP is applied only to 60khz subcarrier spacing. Meanwhile, as a frame structure in NR, a frame having a length of 10ms, which is composed of 10 subframes having the same length of 1ms, is defined. One frame may be divided into half frames of 5ms, and each half frame may include 5 subframes. With a 15khz subcarrier spacing, one subframe is composed of one slot, and each slot is composed of 14 OFDM symbols. Fig. 2 is a schematic diagram of a frame structure in an NR system to which the present embodiment can be applied.

Referring to fig. 2, in the case of the normal CP, a slot is fixedly composed of 14 OFDM symbols, but the length of the slot in the time domain may vary according to subcarrier spacing. For example, in the case of a parameter set with a 15khz subcarrier spacing, the slots have the same length as the subframes, such as a length of 1 ms. In contrast, in the case of a parameter set having a subcarrier spacing of 30kHz, a slot is composed of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. In other words, subframes and frames are defined to have a fixed length, and slots are defined as the number of symbols, and the time length may vary according to the subcarrier spacing.

Meanwhile, NR defines a slot as a basic unit of scheduling, and in order to reduce transmission delay in a wireless section, micro-slot (or sub-slot based or non-slot based scheduling) is employed. If a wide subcarrier spacing is used, the length of one slot is inversely proportional shortened, so that a transmission delay in a wireless section can be reduced. The minislot is used to efficiently support URLLC scenarios and can be scheduled in units of 2,4, or 7 symbols.

Further, unlike LTE, NR defines uplink and downlink resource allocation as symbol level in one slot. In order to reduce HARQ delay, a slot structure is defined that enables HARQ ACK/NACK to be directly transmitted in a transmission slot, and this slot structure is referred to as a self-contained structure in the description.

NR is designed to be able to support 256 slots in total, of which 62 slot formats are used in 3GPP Rel-15. In addition, a common frame structure constituting an FDD or TDD frame is supported by a combination of various slots. For example, a slot structure in which all symbols of a slot are configured as a downlink, a slot structure in which all symbols are configured as an uplink, and a slot structure in which downlink symbols and uplink symbols are combined are supported. In addition, NR supports data transmission that is distributed and scheduled in one or more time slots. Thus, the base station may use the slot format indicator (slot format indicator, SFI) to inform the UE whether the slot is a downlink slot, an uplink slot, or a flexible slot. With SFI, the base station may indicate the slot format by indicating an index of a table configured via UE-specific RRC signaling, and may indicate the slot format dynamically or semi-statically by RRC through downlink control information (downlink control information, DCI).

< NR physical resource >

Antenna ports, resource grids, resource elements, resource blocks and bandwidth parts are considered in connection with the physical resources in the NR.

The antenna ports are defined such that a channel carrying a symbol on an antenna port can be inferred from a channel carrying another symbol on the same antenna port. If the large scale characteristics of the channels carrying symbols on one antenna port can be inferred from the channels carrying symbols on a different antenna port, then the two antenna ports can be said to have a QC/QCL (quasi co-located/quasi co-located) relationship. Here, the large scale characteristics include one or more of delay spread, doppler spread, frequency shift, average received power, and reception timing.

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

Referring to fig. 3, since NRs support a plurality of parameter sets in the same carrier, a resource grid may exist according to each parameter set. Further, the resource grid may exist according to antenna ports, subcarrier spacing, or transmission direction.

The resource block consists of 12 subcarriers and is defined only in the frequency domain. Furthermore, the resource elements are composed of one OFDM symbol and one subcarrier. Thus, as shown in fig. 3, the size of one resource block may vary according to the subcarrier spacing. Further, in NR, a "point a" serving as a common reference point of a resource block grid is defined, as well as common resource blocks and virtual resource blocks.

Fig. 4 is a schematic diagram of a bandwidth portion supported by a radio access technology to which the present embodiment can be applied.

In NR, unlike LTE, where the carrier bandwidth is fixed to 20Mhz, a maximum carrier bandwidth of from 50Mhz to 400Mhz is set for each subcarrier interval. Therefore, it is not assumed that all UEs use all of these carrier bandwidths. Thus, in NR, as shown in fig. 4, a bandwidth part (BWP) may be designated within a carrier bandwidth and used by a UE. Furthermore, the bandwidth part is associated with one parameter set and consists of a subset of consecutive common resource blocks and can be dynamically activated over time. Up to four bandwidth parts may be configured in the UE for each of the uplink and downlink. The data is transmitted/received using the portion of bandwidth that is active at a given time.

In the case of paired spectrum, the uplink bandwidth portion and the downlink bandwidth portion are set independently, while in the case of unpaired spectrum, the uplink bandwidth portion and the downlink bandwidth portion are set as pairs to share a center frequency to prevent unnecessary frequency retuning between downlink and uplink operations.

< NR initial Access >

In NR, the UE performs a cell search and random access procedure to access a base station and performs communication.

Cell search is a procedure such that: the UE synchronizes with a cell of the base station using a synchronization signal block (synchronization signal block, SSB) transmitted by the base station, obtains a physical layer cell ID, and obtains system information.

Fig. 5 is an exemplary diagram of a synchronization signal block in a radio access technology to which the present embodiment can be applied.

Referring to fig. 5, ssb is composed of primary and secondary synchronization signals (primary synchronization signal, PSS) and (secondary synchronization signal, SSS) occupying 1 symbol and 127 subcarriers, respectively, and PBCH spanning 3 OFDM symbols and 240 subcarriers.

The UE monitors the SSB in the time and frequency domains and receives the SSB.

SSBs may be transmitted up to 64 times in 5 milliseconds. Multiple SSBs are transmitted on different transmission beams in a time of 5ms, and the UE performs detection assuming that SSBs are transmitted every 20ms period based on one specific beam for transmission. The number of beams available for SSB transmission within 5ms may increase with increasing frequency band. For example, up to 4 SSB beams may be transmitted below 3GHz, up to 8 different beams may be used to transmit SSBs in the frequency band of 3GHz to 6GHz, and up to 64 different beams may be used to transmit SSBs in the frequency band of 6GHz or higher.

Two SSBs are included in one slot, and the start symbol and the number of repetitions within the slot are determined according to the subcarrier spacing as follows.

Meanwhile, unlike the SS of the conventional LTE, SSB is not transmitted on the center frequency of the carrier bandwidth. In other words, SSBs may be transmitted even outside the center of the system band, and in the case of supporting wideband operation, multiple SSBs may be transmitted in the frequency domain. Thus, the UE monitors the SSB through a synchronization grid (synchronization raster), which is a candidate frequency location for monitoring the SSB. A carrier grid and a synchronization grid are newly defined in NR, which are center frequency location information about an initial access channel, the synchronization grid having a wider frequency interval than the carrier grid so that a UE can perform a rapid SSB search.

The UE may obtain MIB through PBCH of SSB. The master information block (master information block, MIB) includes minimum information for the UE to receive remaining system information (remaining minimum system information (REMAINING MINIMUM SYSTEM INFORMATION, RMSI)) broadcasted by the network. Further, the PBCH may include information about the location of the first DM-RS symbol in the time domain, information that the UE monitors SIB1 (e.g., SIB1 parameter set information, SIB1 CORESET-related information, search space information, PDCCH-related parameter information, etc.), offset information between the common resource block and the SSB (absolute location of the SSB within the carrier is transmitted through SIB 1), and the like. Here, SIB1 parameter set information is equally applicable to some messages used in a random access procedure in which a UE accesses a base station after completing a cell search procedure. For example, the parameter set information on SIB1 may be applied to at least one of messages 1 to 4 for the random access procedure.

The RMSI above may refer to system information block 1 (SIB 1). SIB1 is broadcast periodically (e.g., 160 ms) in a cell. SIB1 includes information required for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order to receive SIB1, the UE needs to receive parameter set information for SIB1 transmission and control resource set (control resource set, CORESET) information for SIB1 scheduling through the PBCH. The UE uses the SI-RNTI in CORESET to identify the scheduling information of SIB1 and obtains SIB1 on the PDSCH according to the scheduling information. The rest of the SIBs except SIB1 may be periodically transmitted and may be transmitted at the request of the UE.

Referring to fig. 6, if 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 the PRACH. Specifically, in a specific time slot periodically repeated, a random access preamble is transmitted to a base station through PRACH consisting of consecutive radio resources. In general, when a UE initially accesses a cell, a contention-based random access procedure is performed, and when random access for beam fault recovery (beam failure recovery, BFR) is performed, a non-contention-based random access procedure is performed.

The UE receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble Identifier (ID), an uplink radio resource (UL grant), a temporary cell radio network temporary identifier (cell-radio network temporary identifier, C-RNTI), and a time alignment command (TIME ALIGNMENT command, TAC). Since one random access response may include random access response information for one or more UEs, a random access preamble identifier may be included to indicate which UE the included UL grant, temporary C-RNTI, and TAC are valid for. The random access preamble identifier may be an identifier of a 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, i.e. a random access radio network temporary identifier (RA-RNTI).

Upon receiving the valid random access response, the UE processes information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies TAC and stores temporary C-RNTI. Further, the UE transmits data stored in a buffer of the UE or newly generated data to the base station using UL grant. In this case, information that can identify the UE should be included.

Finally, the UE receives a downlink message for contention resolution (contention resolution).

In NR, a downlink control channel is transmitted in a control resource set (CORESET) of 1 to 3 symbols in length, and uplink/downlink scheduling information, slot format index (slot format index, SFI), transmission power control (transmit power control, TPC) information, and the like are transmitted.

Thus, NR introduced the concept of CORESET to ensure flexibility of the system. The control resource set (CORESET) refers to time-frequency resources for the downlink control signal. The UE may decode the candidate control channels using one or more search spaces in CORESET time-frequency resources. A quasi co-location (QCL) hypothesis is set for each CORESET, which is used to indicate the characteristics of the analog beam direction, and in addition to delay spread, doppler shift, and average delay, which are the characteristics assumed by conventional QCL.

Fig. 7 is a schematic diagram of CORESET.

Referring to fig. 7, coreset may exist in various forms within a carrier bandwidth within one slot. In the time domain CORESET may consist of up to 3 OFDM symbols. Further CORESET is defined as a multiple of 6 resource blocks in the frequency domain (up to carrier bandwidth).

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

As used herein, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, and various messages related to a new air interface (NR) may be interpreted as various meanings that are currently used or that are used in the future.

< Side Link >

In a conventional LTE system, in order to perform direct communication between UEs and provide V2X (particularly V2V) services, a wireless channel and a wireless protocol are designed for direct communication (i.e., side link) between UEs.

Regarding the side links, S-PSS/S-SSS, which are synchronization signals for synchronization between a radio side link transmitting end and a receiving end, and physical side link broadcast channels (PHYSICAL SIDELINK broadcasting channel, PSBCH), which are side link Master Information Blocks (MIB) for transmission and reception associated therewith, are defined, and physical side link discovery channels (PHYSICAL SIDELINK discovery channel, PSDCH), physical side link control channels (PHYSICAL SIDELINK control channels, PSCCH) for transmission/reception of side link control information (sidelink control information, SCI), and physical side link shared channels (PHYSICAL SIDELINK SHARED CHANNEL, PSSCH) are designed.

In addition, in order to allocate radio resources for the side link, the technology is separately developed into mode 1 in which the base station allocates radio resources and mode 2 in which the UE selects and allocates radio resources from the radio resource pool. Furthermore, LTE systems require additional technical evolution to meet V2X scenarios.

In this environment, the 3GPP derives 27 traffic scenarios related to vehicle identification in Rel-14, and determines the main performance requirements according to road conditions. Furthermore, in recent Rel-15, 25 more advanced business scenarios, such as convoy, advanced driving and remote vehicle sensors, were deduced and six performance requirements were determined.

In order to meet these performance requirements, technology development is performed to improve the performance of the side link technology developed based on the conventional D2D communication, thereby meeting the V2X requirements. In particular, for application to cellular-V2X (C-V2X), techniques for enhancing the physical layer design of the side link to accommodate high-speed environments, resource allocation techniques, and synchronization techniques may be selected as main research techniques.

The side links described below may be understood to include links for D2D communications developed after 3GPP Rel-12, V2X communications after Rel-14, and NR V2X after Rel-15. Furthermore, each channel term, synchronization term and resource term are described with the same terminology regardless of D2D communication requirements and V2X Rel-14 and 15 requirements. However, for ease of understanding, the difference of the side link satisfying the V2X scene requirement from the side link for D2D communication in Rel-12/13 is mainly described as needed. Accordingly, for ease of understanding and comparison, the side link related terms described below are divided only for D2D communication/V2X communication/C-V2X communication and are not limited to a particular scenario.

< Resource Allocation >

Fig. 8 is a schematic diagram of various scenarios of V2X communication.

Referring to fig. 8, V2X UEs (labeled vehicle, but may be arranged in various ways, e.g., UEs) may be located within or outside the coverage of a base station (eNB or gNB or ng-NB). For example, communication may be performed between UEs (UE N-1, UE G-1, and UE X) within the coverage of a base station, or communication may be performed between UEs (e.g., UE N-1 and UE N-2) within the coverage of a base station and outside the coverage of a base station. Or communication may be performed between UEs outside the coverage of the base station (e.g., UE G-1 and UE G-2).

In these different scenarios, in order for the corresponding UE to perform communication using the side link, it is necessary to allocate radio resources for communication, and allocation of radio resources largely includes base station processing allocation and UE self-selection and allocation.

Specifically, the scheme of the UE allocating resources in the side link includes a scheme (mode 1) in which the base station participates in selection and management of resources and a scheme (mode 2) in which the UE itself selects resources. In mode 1, the base station schedules a scheduling assignment (scheduling assignment, SA) pool resource region and a DATA pool resource region allocated thereto to the transmitting UE.

Meanwhile, the resource pool may be subdivided into several types. First, the resource pools may be divided according to the contents of side chain signals transmitted in each resource pool. For example, the content of the sidelink signal may be partitioned and a separate resource pool may be configured for each content. As the content of the sidelink signal, there may be Scheduling Assignment (SA), sidelink data channel, and discovery channel.

The SA may be a signal including information such as: the location of resources used by the transmitting UE in the transmission of the subsequent sidelink data channel, the modulation and coding scheme (modulation and coding scheme, MCS) or MIMO transmission scheme required to modulate the other data channels, and the timing advance (TIMING ADVANCE, TA). The signal may be multiplexed and transmitted with the side link data on the same resource unit, in which case the SA resource pool may refer to a resource pool in which the SA is multiplexed and transmitted with the side link data.

Meanwhile, the FDM scheme applied to V2X communication can reduce delay time when data resources are allocated after SA resource allocation. For example, consider a non-adjacent scheme of separating control channel resources and data channel resources in one subframe in the time domain and an adjacent scheme of continuously allocating control channels and data channels in one subframe.

Meanwhile, when the SA is multiplexed and transmitted on the same resource unit as the side link data, only the side link data channels other than the SA information may be transmitted in the resource pool for the side link data channels. In other words, the resource elements already used for transmitting SA information on a single resource element in the SA resource pool can still be used for transmitting side link data in the side link data channel resource pool. The discovery channel may be a pool of resources for messages to allow a transmitting UE to send its ID or such information to be discovered by neighboring UEs. Even when the contents of the side link signals are the same, different resource pools may be used according to the transmission/reception properties of the side link signals.

For example, regardless of the sidelink data channels or discovery messages, they may be divided into different resource pools according to the following: a side link signal transmission timing determination scheme (e.g., whether to transmit upon receiving a synchronization reference signal or to transmit with applying a predetermined TA), a resource allocation scheme (e.g., whether the base station specifies transmission resources of individual signals for the UE or the individual transmitting UE selects the individual signal transmission resources by itself), a signal format (e.g., the number of symbols each side link signal occupies in one subframe or the number of subframes used to transmit one side link signal), a signal strength from the base station, or a transmission power strength of the side link UE.

< Synchronization Signal >

As described above, the side link communication UE is highly likely to be located outside the coverage of the base station. Even in this case, communication using the side link should be performed. For this reason, the problem of obtaining synchronization by UEs located outside the coverage of the base station is important.

Based on the above description, a method for time and frequency synchronization of sidelink communications, in particular communications between vehicles, between a vehicle and another UE, and between a vehicle and an infrastructure network, is described.

D2D communication uses a Side Link Synchronization Signal (SLSS), which is a synchronization signal transmitted from a base station for time synchronization between UEs. In C-V2X, satellite systems (Global navigation satellite System (global navigation SATELLITE SYSTEM, GNSS)) may be additionally considered to enhance synchronization performance. However, priority may be given to synchronization establishment, or the base station may indicate priority information. For example, in determining that the transmissions of the UE are synchronized, the UE first selects a synchronization signal to be directly transmitted by the base station, and if the UE is located at the edge of the coverage of the base station, the synchronization is preferentially performed with SLSS transmitted by UEs within the coverage of the base station.

Meanwhile, a wireless UE installed in a vehicle or a UE installed on a vehicle is relatively less susceptible to battery consumption problems, and a satellite signal (e.g., GPS) can be used for navigation purposes, so that the satellite signal can be used when time and frequency synchronization is established between UEs. Here, the satellite signals may be GNSS signals, such as global navigation satellite system (GLONAS), GALILEO, and beiou, in addition to the example Global Positioning System (GPS).

Meanwhile, the side link synchronization signals may include side link primary synchronization signals (SIDELINK PRIMARY synchronization signal, S-PSS) and side link secondary synchronization signals (sidelink secondary synchronization signal, S-SSS). The S-PSS may have a Zadoff-chu sequence of a predetermined length or a similar/modified/repeated structure of the PSS. Further, other Zadoff-Chu root indices (e.g., 26 and 37) may be used, unlike DL PSS. S-SSS may have a similar/modified/repeated structure of SSS or M sequences. If the UE synchronizes from the base station, the SRN becomes the base station and the side link synchronization signal (sidelink synchronization signal, S-SS) becomes the PSS/SSS.

Unlike the DL PSS/SSS, the S-PSS/S-SSS follows the UL subcarrier mapping scheme. The physical side link broadcast channel (PHYSICAL SIDELINK broadcast channel, PSBCH) may be such a channel: in this channel, the UE first needs to know basic system information (e.g., information related to S-SS, duplex Mode (DM), TDD UL/DL configuration, information related to resource pool, application type related to S-SS, subframe offset, broadcast information, etc.) before transmitting and receiving side-chain signals. The PSBCH may be transmitted on the same subframe as the S-SS or on a subsequent subframe. DMRS may be used for demodulation of PSBCH. The S-SS and PSBCH may be referred to as a side link synchronization signal block (sidelink synchronization signal block, S-SSB).

The SRN may be a node transmitting the S-SS and PSBCH. S-SS may have a particular sequence form. The PSBCH may have the form of a sequence indicating specific information or a codeword subjected to predetermined channel coding. Here, the SRN may be a base station or a specific side chain UE. In the case of partial network coverage or outside of network coverage, the UE may become an SRN.

In addition, the S-SS may be relayed as needed for side-link communication with out-of-coverage UEs, and may be relayed through multiple hops. In the following description, the relay synchronization signal is a concept including not only a synchronization signal of a direct relay base station but also a transmission side link synchronization signal in a separate format according to a synchronization signal reception time. When the side link synchronization signal is thus relayed, the UE in the coverage area and the UE out of the coverage area can directly communicate.

< NR side Link >

As described above, unlike V2X based on LTE systems, NR based V2X technology is required to meet complex requirements, such as autopilot.

NR V2X is intended to flexibly provide V2X service in a more diverse environment by applying a frame structure, a parameter set, and a channel transmission and reception procedure of NR. For this, development of technologies such as a resource sharing technology between a base station and a UE, a side chain carrier aggregation (CARRIER AGGREGATI, CA) technology, a partial sensing technology of a pedestrian UE, and sTTI is necessary.

NR V2X is determined to support unicast and multicast as well as broadcast used in LTE V2X. In this case, for multicast and unicast, it is determined to use the target group ID, but determination of whether to use the source ID will be discussed later.

Further, since HARQ for QoS is supported, control information is also determined to include HARQ process ID. In LTE HARQ, the PUCCH of HARQ is transmitted four subframes after downlink transmission. However, in NR HARQ, PUCCH resources and feedback timing may be indicated by, for example, a PUCCH resource indicator or PDSCH-to-HARQ feedback timing indicator in DCI format 1_0 or 1_1.

In LTE V2X, separate HARQ ACK/NACK information is not transmitted to reduce overhead, and for data transmission stability, the transmitting UE is determined to be able to retransmit data once according to its choice. However, NR V2X is able to transmit HARQ ACK/NACK information according to data transmission stability, in which case information is bundled and transmitted, reducing overhead.

In other words, the transmitting UE1 may transmit three data to the receiving UE2, and if the receiving UE generates HARQ ACK/NACK information as a response, the information may be bundled and transmitted through the PSCCH.

Meanwhile, in FR1 in the frequency domain below 3GHz, 15kHz, 30kHz, 60kHz, and 120kHz are determined to be discussed later as subcarrier spacing (subcarrier spacing, SCS) candidates. Further, for FR2 in the frequency domain above 3GHz, it was determined that 30kHz, 60kHz, 120kHz, and 240kHz were discussed as subcarrier spacing (SCS) candidates. NR V2X may support a minislot of less than 14 symbols (e.g., 2/4/7 symbols) as a minimum scheduling unit.

As RS candidates, the discussion DM-RS, PT-RS, CSI-RS, SRS and AGC training signals are determined.

Side link UL SPS

In general, UL transmissions using SPS may cause some delay when the gap between user data generation and configured SPS resources is large. Thus, when SPS is used for delay sensitive traffic (e.g., side link communications), the SPS scheduling interval should be small enough to support the delay requirement.

However, a smaller SPS scheduling interval may result in more overhead because the UE may not fully utilize the configured SPS resources. Therefore, the gap between user data generation and the configured SPS resources should be small and the SPS scheduling interval should be suitable to meet the delay requirement. Currently, there is no mechanism to support this function.

The UE may receive SPS configurations for one or more particular logical channels. The UE may receive SPS configuration for a particular logical channel through system information, an RRC connection setup message, an RRC connection reconfiguration message, or an RRC connection release message.

When data is available for a particular logical channel, the UE may request the base station to activate SPS and then perform UL transmission using the configured SPS resources according to an SPS activation command received from the base station. The UE may transmit an SPS activation request to the base station through a Physical Uplink Control Channel (PUCCH), a MAC Control Element (CE), or an RRC message. In other words, the UE may send an SPS activation request to the base station using the control resources for requesting SPS activation. The control resource may be a PUCCH resource, a random access resource, or a new UL control channel resource. Further, the UE may send an SPS activation request to the base station during e.g. RRC connection (re) establishment, during handover, after handover or in rrc_connected.

Since the UE actively requests SPS activation from the base station when there is UL data to be transmitted, a gap between generation of UL data and configured SPS resources can be reduced.

For example, the UE receives SPS configuration information including three SPS configurations from the base station. If there is UL data to be transmitted in the upper layer, the UE transmits an SPS request message to the base station, for example, through the MAC CE. The base station transmits an Ack message for one of the three SPS configurations. The UE transmits UL data through a specific resource according to a corresponding SPS configuration, for example, within a 1 second period.

Meanwhile, if UL data to be transmitted exists at an upper layer at a specific time, the UE transmits an SPS request message to the base station again through, for example, MAC CE. The base station transmits an Ack message for another of the three SPS configurations. The UE transmits UL data through a specific resource according to a corresponding SPS configuration, for example, within a period of 100 seconds.

Meanwhile, S-SS id_net is a set of S-SSIDs used by UEs that select a synchronization signal of a base station as a synchronization reference in the physical layer SLSSID {0,1, …,335} and may be {0,1, …,167}. Further, S-SS id_oon is a set of S-SSIDs used when the base station/out-of-coverage UE itself transmits a synchronization signal, and may be {168, 169, …,335}.

As described above, unlike conventional signal transmission and reception between a base station and a UE, side link communication between UEs performs resource allocation, time synchronization setting, and reference signal transmission independently or in combination with the base station.

In particular, in the case of the next generation radio access technology (including terms such as NR and 5G), many protocols between the base station and the UE are added/modified. Thus, unlike the conventional V2X communication protocol based on the LTE technology, the side link communication based on the NR technology also needs to develop various protocols.

In the present disclosure, operations such as PSCCH, PSSCH, or DMRS configuration, resource allocation, and synchronization signal reception when a transmitting UE and a receiving UE perform side link communication are proposed. Each of the following embodiments focuses on side link communication for description, but may also be applied to C-V2X and D2D communication as described above.

Since the subcarrier spacing (SCS) of the OFDM communication system varies in NR, it is also necessary to change the frame structure of the side link for information transmission and reception in the side link communication.

In the present embodiment, the side link signal may use CP-OFDM type waveforms of CP-OFDM type and DFT-s-OFDM type. In addition, the side link may use the following subcarrier spacing (hereinafter, referred to as "SCS"). For example, in a Frequency Range (FR) 1 using a frequency band of less than 6GHz, SCS of 15kHz, 30kHz and 60kHz is used, and in this case, 60kHz intervals exhibiting the best performance may be set to be inactive. In FR2 using a frequency band of 6GHz or more, an interval of 60kHz and 120kHz is used, and a frequency band of 60kHz may be mainly used.

Further, the side link uses a Cyclic Prefix (CP) to prevent modulation that may occur during wireless communication transmission/reception, and its length may be set equal to that of the normal CP of the NR Uu interface. An extended CP may be applied if necessary.

As described above, the side link communication can be performed based on the NR radio access technology. Further, given a scenario of communication with a side link, there is a possibility that a plurality of UEs are gathered within a predetermined range and perform communication, such as when traveling in a formation.

In this case, radio resources for side link communication may frequently collide with each other. In particular, a procedure for resolving resource collision may be required in mode 2 in which the UE selects a side link communication resource from a predetermined resource pool based on a sensing operation, unlike in mode 1 in which the side link communication resource is allocated and scheduled by the base station.

In these cases, an embodiment of the radio resource coordination technique is described below.

Referring to fig. 9, side-chain communication may be performed between a UE-B (TX UE) 900 and an RX UE 920. In this case, the UE-B900 transmits data to the RX-UE (920) using resources for performing side link communication.

However, in the case where the UE-B900 selects a side link resource allocation mode of resources for performing side link communication, the resources used by other UEs may overlap. If the resources overlap, side link communication may not be smoothly performed.

Thus, the UE-A910 may send coordination information to the UE-B900 to prevent resource conflict issues. For example, the UE-B900 may prevent collision by selecting radio resources to be used for side link communication based on received coordination information (RSAI). In other words, the UE-A910 may be a coordinator UE that provides resource selection assistance information (resource selection assistance information, RSAI) to the UE-B900 through inter-UE coordination. Meanwhile, UE-B900 is a TX UE that receives coordination information from UE-A910.

In particular, the following embodiments may be applied to coordination between UEs in side link resource allocation mode 2 (a mode in which the UE selects side link resources by itself).

For example, upon request of the UE-B900, the UE-A910 may send to the UE-B900 preferred resource information that the UE-B900 may use and/or non-preferred resource information that the UE-B900 may not use.

As another example, even without a request from UE-B900, UE-a 910 may send to UE-B900 coordination information indicating whether there is a collision and the collision resources of side-chain radio resources that UE-B900 intends to use.

However, in the embodiment of transmitting and receiving the coordination information as described above, there are various execution problems such as whether the UE-B900 can process the coordination information and what information should be included in the coordination information. Accordingly, various embodiments are described in greater detail below, with an emphasis on operations for coordinating smooth transmission/reception of information. For convenience of description, a UE receiving coordination information is referred to as a UE, and a UE transmitting coordination information is referred to as a second UE. However, the role of each UE may be described in detail as needed.

Referring to fig. 10, the UE may perform a step of transmitting side chain control information including request information for requesting coordination information and indication information indicating a resource type to be included in the coordination information to the second UE (S1010).

The UE may be configured to select the side-link radio resources by receiving coordination information through higher layer signaling. Higher layer signaling may be received from a base station and may be an RRC message. For example, whether to process coordination information of the UE may be indicated by disabling or enabling processing of a specific field in the RRC message.

The UE may request coordination information to select resources for side link communication.

For example, the UE may include request information for requesting coordination information in side chain control information and transmit it to the second UE. As another example, the UE may include indication information for indicating the type of resources to be included in the coordination information in the side chain control information and transmit it to the second UE. As another example, the UE may include the request information and the indication information in side chain control information at the same time and transmit them to the second UE.

For example, side link control information including the request information and/or the indication information may be transmitted through a physical side link shared channel (PSSCH). The side link control information includes first side link control information included in the PSCCH and second side link control information included in the PSSCH. In this case, the above request information and/or the instruction information may be included in the second side chain control information.

Specifically, the request information may indicate whether the UE requests coordination information.

For example, the request information may be indicated by a value of a first field consisting of 1 bit included in the side chain control information. The value of the first field may be used to identify whether the side link control information is used to request coordination information or to provide coordination information. In other words, the first field is a field for identifying whether side chain control information including request information is used for requesting coordination information or for including and providing coordination information. For example, if the value of the first field is set to "0", it may refer to the corresponding side chain control information being used to request coordination information, and the value of the other field and/or the other field may be changed accordingly. If the value of the first field is set to "1", it may mean that the corresponding side chain control information may include coordination information, and in this case, coordination information may be additionally included. Of course, the values of the first fields may be set opposite to each other.

As another example, the indication information may be indicated by a value of a second field consisting of 1 bit different from the first field included in the side link control information. For example, when the value of the first field is set to request coordination information, the second field may be included in the side chain control information. The second field may indicate which resource type is requested by the coordination information requested by the UE. For example, the second UE transmitting the coordination information may include preferred resource information in the coordination information and transmit the preferred resource information. Alternatively, the second UE may include non-preferred resource information in the coordination information and transmit the non-preferred resource information. Thus, when coordination information is requested, the UE may specify which information (resource type) is requested. In other words, the value of the second field may be used to indicate the resource type of any one of the preferred resource information and the non-preferred resource information determined by the second UE. If the value of the second field is set to "0", it may be interpreted that the UE requests transmission of the preferred resource information through the coordination information. Or if the value of the second field is set to "1", it may be interpreted that the UE requests transmission of non-preferred resource information through coordination information.

As described above, the UE may also request a required resource type when requesting coordination information.

The UE may perform the step of receiving coordination information from the second UE (S1020).

For example, when the UE requests coordination information, the UE may receive coordination information from the second UE. The coordination information may be received over a PSSCH or PSCCH. If the second UE receives side link control information requesting coordination information from the UE, the second UE may generate preferred resource information or non-preferred resource information in consideration of, for example, a resource sensing result sensed by the second UE, resource usage information, and the like. Further, the second UE may generate any one of the preferred resource information and the non-preferred resource information based on the indication information received from the UE and transmit it to the UE.

The UE may receive preferred resource information or non-preferred resource information from the second UE through the coordination information based on the transmission of the side chain control information including the request information and the indication information.

The UE may perform the step of determining resources for performing side link communication based on at least one of the coordination information and the resource sensing information (S1030).

For example, the UE may select a resource for performing side-link communication using at least one of the coordination information and the sensing result resource information sensed in the sensing window. The UE should select side-link radio resources to communicate with the target UE (RX UE 920 in fig. 9). In particular, in mode 2, since the base station configures a side chain radio resource pool in the UE and the UE selects resources within the pool, the UE should directly select resources to be used.

In order to select the side link radio resources, the UE selects a specific radio resource using a resource sensing result in a preset sensing window. As the resource sensing result, a channel measurement result such as RSRP for a specific frequency resource may be used.

Meanwhile, the UE according to the present embodiment may select a side-chain radio resource using both the sensing result resource information and the above-described coordination information.

For example, when the preferred resource information is included in the coordination information, the UE may select a resource commonly included in the sensing result resource information and the preferred resource information as a resource for performing side link communication.

As another example, when the coordination information includes the preferred resource information, the UE may select a resource for performing side-chain communication from the preferred resource information without using the sensing result resource information.

As another example, when non-preferred resource information is included in the coordination information, the UE may select resources other than the radio resources included in the non-preferred resources from the sensing result resource information for performing the side link communication.

The above preferred resource information may include information on radio resources preferred by the second UE to be used by the UE. The non-preferred resource information may include information on radio resources that the second UE expects the UE not to use.

Accordingly, when the coordination information is received, the UE may select side-chain radio resources based on the sensing result resource information and the coordination information. By this operation, even in an environment in which a plurality of UEs perform side link communication, the UEs can reduce the probability of communication problems due to resource conflicts. Further, by requesting coordination information and indicating a specific resource type as needed, unnecessary increases in system overhead can be prevented.

The above description has focused mainly on an operation according to an explicit request in a scheme of transmitting/receiving coordination information, but the present disclosure is not limited thereto. Further various embodiments that may be performed by the UE described above are described in detail below.

For example, the UE may transmit an N-bit index through a specific side link control information format to transmit the type of inter-UE coordination information required to sense side link resources to the second UE.

For example, an index of N bits may be composed of 2 bits. The 2-bit index may indicate whether the UE requests coordination information and the requested resource type, as shown in table 2 below. Table 2 exemplarily discloses contents of a one-time request coordination information scheme type using 2 bits.

TABLE 2

As another example, the UE may use one of two bits to indicate whether coordination information is requested. Further, the UE may use another bit to indicate the type of resource requested. For example, the UE may indicate whether to request coordination information using one bit as shown in table 3 and indicate a resource type through the remaining one bit.

TABLE 3

First bit	Second bit	Content of the request
			0	-	Does not request any coordination information
1	-	Requesting coordination information
			-	0	Requesting a preferred set of resources
-	1	Requesting a set of non-preferred resources

The 2 bits may be configured in the same field or in different fields. As another example, the UE may include information indicating whether coordination information can be received in side chain control information transmitted over the PSCCH. In other words, when the UE indicates that coordination information can be received in the sidelink control information transmitted through the PSCCH, the second UE may transmit coordination information indicating whether a collision occurs when it collides or expects a collision with sidelink radio resources reserved for use by the UE.

As described above, the UE may request coordination information and indicate a resource type through various methods.

The configuration of the UE described above is described again below with reference to the accompanying drawings.

Referring to fig. 11, a UE 1100 performing side link communication may include: a transmitter 1120, the transmitter 1120 transmitting side link control information to the second UE, the side link control information including request information for requesting coordination information and indication information indicating a type of resources to be included in the coordination information: a receiver 1130 that receives coordination information from the second UE; and a controller 1110 determining resources for performing side link communication based on at least one of the coordination information and the resource sensing information.

UE 1100 may be configured to select side-link radio resources by higher layer signaling to receive coordination information. Higher layer signaling may be received from a base station and may be an RRC message. For example, whether to process coordination information of the UE may be indicated by disabling or enabling processing of a specific field in the RRC message.

UE 1100 may request coordination information to select resources for side-link communications.

For example, the transmitter 1120 may include request information for requesting coordination information in side chain control information and transmit it to the second UE. As another example, the transmitter 1120 may include indication information for indicating the type of resources to be included in the coordination information in the side chain control information and transmit it to the second UE. As another example, the transmitter 1120 may include request information and indication information in the side chain control information at the same time and transmit it to the second UE.

For example, side link control information including request information and/or indication information may be transmitted through a physical side link shared channel (PSSCH). The side link control information includes first side link control information included in the PSCCH and second side link control information included in the PSSCH. In this case, the above request information and/or the instruction information may be included in the second side chain control information.

For example, the request information may be indicated by a value of a first field consisting of 1 bit included in the side chain control information. The value of the first field may be used to identify whether the side link control information is used to request coordination information or to provide coordination information. In other words, the first field is a field for identifying whether side chain control information including request information is used for requesting coordination information or for including and providing coordination information. For example, if the value of the first field is set to "0", it may refer to the corresponding side chain control information being used to request coordination information, and the value of the other field and/or the other field may be changed accordingly. If the value of the first field is set to "1", it may mean that the corresponding side chain control information may include coordination information, in which case coordination information may be additionally included. Of course, the values of the first fields may be set opposite to each other.

Meanwhile, when coordination information is requested, the receiver 1130 may receive the coordination information from the second UE. The coordination information may be received over a PSSCH or PSCCH. If the second UE receives side link control information requesting coordination information from the UE, the second UE may generate preferred resource information or non-preferred resource information in consideration of, for example, a resource sensing result sensed by the second UE, resource usage information, and the like. Further, the second UE may generate any one of the preferred resource information and the non-preferred resource information based on the indication information received from the UE and transmit it to the UE.

The receiver 1130 may receive the preferred resource information or the non-preferred resource information from the second UE through the coordination information based on the transmission of the side chain control information including the request information and the indication information.

Meanwhile, the controller 1110 may determine resources for performing side-link communication based on the coordination information.

For example, the controller 1110 may select a resource for performing side-link communication using at least one of coordination information and sensing result resource information sensed in a sensing window.

To select the side-link radio resource, the controller 1110 selects a specific radio resource using a resource sensing result in a preset sensing window. As the resource sensing result, a channel measurement result such as RSRP for a specific frequency resource may be used.

For example, when the preferred resource information is included in the coordination information, the controller 1110 may select a resource commonly included in the sensing result resource information and the preferred resource information as a resource for performing side-link communication.

As another example, when the coordination information includes the preferred resource information, the controller 1110 may select a resource for performing side-link communication from the preferred resource information without using the sensing result resource information.

As another example, when non-preferred resource information is included in the coordination information, the controller 1110 may select resources other than the radio resources included in the non-preferred resources from the sensing result resource information for performing side-link communication.

Further, the controller 1110 may control the operation of the UE 1100 required to perform the above-described embodiments.

In addition, the transmitter 1120 and the receiver 1130 transmit/receive signals, data, and messages with the base station and another UE through corresponding channels.

The above-described embodiments may be supported by standard documents disclosed in IEEE 802, 3GPP, and 3GPP2 as wireless access systems. In other words, the above-described standard documents may support steps, components and parts which are not described in order to clarify the technical spirit in the embodiments. Furthermore, all terms disclosed in the present disclosure may be described by the above-disclosed standard documents.

The present embodiment described above can be implemented in various ways. For example, the present embodiments may be implemented by various means, such as hardware, firmware, software, or a combination thereof.

When implemented in hardware, the method according to the present embodiment may be implemented by, for example, one or more application-specific integrated circuits (ASICs), digital signal processors (DIGITAL SIGNAL processors, DSPs), digital signal processing devices (DIGITAL SIGNAL processing device, DSPDs), programmable logic devices (programmable logic device, PLDs), field programmable gate arrays (field programmable GATE ARRAY, FPGAs), processors, controllers, microcontrollers, or microprocessors.

When implemented in firmware or hardware, the method according to the present embodiment may be implemented in the form of a device, process or function that performs the functions or operations described above. The software codes may be stored in memory units and driven by processors. The memory unit may be located inside or outside the processor to exchange data with the processor in various known ways.

The terms such as "system," "processor," "controller," "component," "module," "interface," "model," or "unit" generally refer to the physical hardware, combination of hardware and software, or software in execution, in relation to a computer. For example, the above-described components may be, but are not limited to being, processes driven by a processor, a controller, a control processor, an entity, a thread of execution, a program, and/or a computer. For example, an application executed by a controller or processor, and the controller or processor may be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one device (e.g., system, computing device, etc.) or distributed between two or more devices.

The above-described embodiments are merely examples, and those of ordinary skill in the art will appreciate that various modifications may be made thereto without departing from the scope of the present invention. Accordingly, the examples set forth herein are provided for the purpose of illustration and are not intended to limit the scope of the invention, and it should be understood that the scope of the invention is not limited by the examples. The scope of the present disclosure should be construed by the following claims, and all technical spirit within its equivalents should be construed as falling within the scope of the present disclosure.

Cross Reference to Related Applications

The present patent application claims priority from korean patent application nos. 10-2021-012696 and 10-2022-012699 filed in the korean intellectual property office on the respective days 2021, 9, 27 and 2022, 9, 26 (a), the entire disclosures of which are incorporated herein by reference. This patent application claims priority from other applications filed in other countries, the entire disclosure of which is also incorporated herein by reference.

Claims

1. A method of performing side link communication by a terminal, the method comprising:

Transmitting side link control information to a second terminal, wherein the side link control information comprises request information for requesting coordination information and indication information for indicating a resource type to be included in the coordination information;

Receiving the coordination information from the second terminal; and

Based on at least one of the coordination information and resource sensing information, a resource for performing the side-link communication is determined.

2. The method of claim 1, wherein the sidelink control information is included in a Physical Sidelink Shared Channel (PSSCH) for transmission.

3. The method of claim 1, wherein the request information is represented by a value of a first field consisting of one bit; and

Wherein the indication information is represented by a value of a second field composed of one bit different from the first field.

4. A method according to claim 3, wherein the value of the first field is used to identify whether the side link control information is used to request the coordination information or to provide the coordination information.

5. A method according to claim 3, wherein the value of the second field is used to indicate the resource type of any one of the preferred resource information and the non-preferred resource information determined by the second terminal.

6. The method of claim 1, wherein determining the resource comprises: at least one of the coordination information and sensing result resource information sensed within a sensing window is used to select a resource for performing the side-link communication.

7. The method of claim 6, wherein determining the resource comprises: when the preferred resource information is included in the coordination information, a resource including the sensing result resource information and a resource commonly included in the preferred resource information is selected as a resource for performing the side link communication.

8. The method of claim 6, wherein determining the resource comprises: when the non-preferred resource information is included in the coordination information, resources other than the radio resources included in the non-preferred resources are selected from the sensing result resource information for performing the side-link communication.

9. A terminal that performs side link communication, comprising:

a transmitter that transmits side link control information including request information for requesting coordination information and indication information indicating a type of resource to be included in the coordination information to a second terminal;

a receiver that receives the coordination information from the second terminal; and

And a controller determining a resource for performing the side link communication based on at least one of the coordination information and the resource sensing information.

10. The terminal of claim 9, wherein the side link control information is included in a physical side link shared channel (PSSCH) for transmission.

11. The terminal of claim 9, wherein the request information is represented by a value of a first field consisting of one bit; and

12. The terminal of claim 11, wherein a value of the first field is used to identify whether the sidelink control information is used to request the coordination information or to provide the coordination information.

13. The terminal of claim 11, wherein a value of the second field is used to indicate a resource type of any one of preferred resource information and non-preferred resource information determined by the second terminal.

14. The terminal of claim 9, wherein the controller uses at least one of the coordination information and sensing result resource information sensed within a sensing window to select a resource for performing the side-link communication.