KR20220100531A - Method for controlling sidelink communication and apparatus thereof - Google Patents

Abstract

The present disclosure relates to a technique for controlling sidelink communication using a DRX operation. According to one embodiment, provided are a method and an apparatus, wherein a method for performing sidelink communication by a terminal comprises the steps of: receiving a sidelink radio resource control (RRC) message from a base station or another terminal; configuring sidelink discontinuous reception (DRX) parameters by using information included in the sidelink RRC message; and monitoring the reception of sidelink data by using the sidelink DRX parameters.

Description

METHOD FOR CONTROLLING SIDELINK COMMUNICATION AND APPARATUS THEREOF

This disclosure relates to techniques for controlling sidelink communication using DRX operation.

There is a demand for large-capacity data processing, high-speed data processing, and various service requests using wireless terminals in vehicles and industrial sites. As described above, there is a need for a technology for a high-speed, large-capacity communication system capable of processing various scenarios and large-capacity data, such as video, wireless data, and machine-type communication data, beyond a simple voice-oriented service.

To this end, ITU-R discloses the requirements for adopting the IMT-2020 international standard, and research on next-generation wireless communication technology to meet the requirements of IMT-2020 is in progress.

In particular, 3GPP is conducting research on the LTE-Advanced Pro Rel-15/16 standard and the NR (New Radio Access Technology) standard in parallel to satisfy the IMT-2020 requirement, which is referred to as 5G technology. to be approved as a next-generation wireless communication technology.

In 5G technology, it can be applied and utilized in autonomous vehicles. To this end, it is necessary to apply 5G technology to sidelink communication (eg, vehicle communication (V2X)), and high-speed transmission/reception is required while ensuring high reliability for increased data for autonomous driving.

In addition, in order to satisfy operation scenarios of various autonomous vehicles such as platooning, various data communication such as multicast data transmission and reception as well as multiple unicast data transmission and reception using sidelink communication should be ensured.

However, for this purpose, the terminal performing sidelink communication must continuously monitor control data or user data in the sidelink radio resource in order to check whether the sidelink communication data is received. This can cause a significant spike in power consumption.

In the background described above, the present disclosure intends to disclose a technique for controlling sidelink communication using a DRX operation.

In one aspect, the present embodiments provide a method for a terminal to perform sidelink communication, the step of receiving a sidelink RRC (Radio Resource Control) message from a base station or another terminal and using information included in the sidelink RRC message. A method is provided, comprising the steps of configuring a sidelink Discontinuous Reception (DRX) parameter and monitoring reception of sidelink data using the sidelink DRX parameter.

In one aspect, the present embodiments provide a method for another terminal to perform sidelink communication, the steps of transmitting a sidelink RRC (Radio Resource Control) message to the terminal and sidelink channel status information (CSI) from the terminal ) receiving a request, and controlling the terminal to transmit sidelink channel state information while the sidelink DRX CSI timer is operating.

In one aspect, the present embodiments provide a terminal for performing sidelink communication, a receiver for receiving a sidelink RRC (Radio Resource Control) message from a base station or another terminal, and a sidelink using information included in the sidelink RRC message. Provided is a terminal device including a controller configured to configure a discontinuous reception (DRX) parameter and monitor reception of sidelink data using the sidelink DRX parameter.

In one aspect, the present embodiments provide sidelink channel status information (CSI) requests from a transmitter for transmitting a sidelink RRC (Radio Resource Control) message to a terminal and a terminal in another terminal performing sidelink communication Another terminal device is provided, comprising: a receiving unit for receiving ;

In the background described above, the present disclosure provides an effect of controlling sidelink communication using a DRX operation.

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which this embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a radio access technology to which the present embodiment can be applied.
5 is a diagram exemplarily illustrating 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 this embodiment can be applied.
7 is a diagram for explaining CORESET.
8 is a diagram exemplarily disclosed the architecture of the V2X communication system in the LTE system.
9 is a diagram for explaining an operation of a terminal according to an embodiment.
10 is a diagram for explaining an operation of another terminal according to an embodiment.
11 is a diagram for explaining a terminal configuration according to an embodiment.
12 is a diagram for explaining the configuration of another terminal according to an embodiment.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present embodiments, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present technical idea, the detailed description may be omitted. When "includes", "having", "consisting of", etc. mentioned in this specification are used, other parts may be added unless "only" is used. When a component is expressed in a singular, it may include a case in which the plural is included unless otherwise explicitly stated.

In addition, in describing the components of the present disclosure, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms.

In the description of the positional relationship of components, when two or more components are described as being "connected", "combined" or "connected", two or more components are directly "connected", "coupled" or "connected" ", but it will be understood that two or more components and other components may be further "interposed" and "connected," "coupled," or "connected." Here, other components may be included in one or more of two or more components that are “connected”, “coupled” or “connected” to each other.

In the description of the temporal flow relation related to the components, the operation method or the manufacturing method, for example, the temporal precedence relationship such as "after", "after", "after", "before", etc. Alternatively, when a flow precedence relationship is described, it may include a case where it is not continuous unless "immediately" or "directly" is used.

On the other hand, when numerical values or corresponding information (eg, level, etc.) for a component are mentioned, even if there is no explicit description separately, the numerical value or the corresponding information is based on various factors (eg, process factors, internal or external shock, It may be interpreted as including an error range that may be caused by noise, etc.).

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

The present embodiments disclosed below may be applied to a wireless communication system using various wireless access technologies. For example, the present embodiments are CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access) Alternatively, it may be applied to various various radio access technologies such as non-orthogonal multiple access (NOMA). In addition, the wireless access technology may mean not only a specific access technology, but also a communication technology for each generation established by various communication consultation organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced datarates for GSM evolution (EDGE). OFDMA may be implemented with a wireless technology such as 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 the universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) that uses evolved-UMTSterrestrial radio access (E-UTRA), and employs OFDMA in downlink and SC- in uplink FDMA is employed. As such, the present embodiments may be applied to currently disclosed or commercialized radio access technologies, or may be applied to radio access technologies currently under development or to be developed in the future.

On the other hand, in the present specification, a terminal is a comprehensive concept meaning a device including a wireless communication module for performing communication with a base station in a wireless communication system, and in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio), etc. It should be interpreted as a concept including all of UE (User Equipment), MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), wireless device, etc. 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 a V2X communication system may mean a vehicle, a device including a wireless communication module in the vehicle, and the like. In addition, in the case of a machine type communication (Machine Type Communication) system, it may mean an MTC terminal, an M2M terminal, a URLLC terminal, etc. equipped with a communication module to perform machine type communication.

A base station or cell of the present specification refers to an end that communicates with a terminal in terms of a network, a Node-B (Node-B), an evolved Node-B (eNB), gNode-B (gNB), a Low Power Node (LPN), Sector, site, various types of antennas, base transceiver system (BTS), access point, point (eg, transmission point, reception point, transmission/reception point), relay node (Relay Node) ), mega cell, macro cell, micro cell, pico cell, femto cell, RRH (Remote Radio Head), RU (Radio Unit), small cell (small cell), etc. In addition, the cell may mean including a BWP (Bandwidth Part) in the frequency domain. For example, the serving cell may mean the Activation BWP of the UE.

In the various cells listed above, since there is a base station controlling one or more cells, the base station can be interpreted in two ways. 1) in relation to the radio area, it may be the device itself providing a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, or a small cell, or 2) may indicate the radio area itself. In 1), the devices providing a predetermined radio area are controlled by the same entity, or all devices interacting to form a radio area cooperatively are directed to the base station. A point, a transmission/reception point, a transmission point, a reception point, etc. become an embodiment of a base station according to a configuration method of a wireless area. In 2), the radio area itself in which the signal is received or transmitted from the point of view of the user terminal or the neighboring base station may be indicated to the base station.

In the present specification, a cell is a component carrier having a coverage of a signal transmitted from a transmission/reception point or a coverage of a signal transmitted from a transmission/reception point (transmission point or transmission/reception point), and the transmission/reception point itself. can

Uplink (Uplink, UL, or uplink) refers to a method for transmitting and receiving data by a terminal to a base station, and downlink (Downlink, DL, or downlink) refers to a method for transmitting and receiving data to and from a terminal by a base station do. A downlink may mean a communication or communication path from a multi-transmission/reception point to a terminal, and an uplink may mean a communication or communication path from the terminal to a multi-transmission/reception point. In this case, 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 the multi-transmission/reception point.

The uplink and the downlink transmit and receive control information through a control channel such as a Physical Downlink Control CHannel (PDCCH), a Physical Uplink Control CHannel (PUCCH), etc., and a Physical Downlink Shared CHannel (PDSCH), a Physical Uplink Shared CHannel (PUSCH), etc Data is transmitted and received by configuring the same data channel. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH may be expressed in the form of 'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'. do.

For clarity of explanation, the present technical idea is mainly described below for a 3GPP LTE/LTE-A/NR (New RAT) communication system, but the present technical features are not limited to the corresponding communication system.

In 3GPP, after research on 4G (4th-Generation) communication technology, 5G (5th-Generation) communication technology is developed to meet the requirements of ITU-R's next-generation wireless access technology. Specifically, 3GPP develops LTE-A pro, which improved LTE-Advanced technology to meet the requirements of ITU-R as a 5G communication technology, and a new NR communication technology separate from 4G communication technology. LTE-A pro and NR both refer to 5G communication technology. Hereinafter, 5G communication technology will be described with a focus on NR unless a specific communication technology is specified.

In the NR operation scenario, various operation scenarios were defined by adding consideration of satellites, automobiles, and new verticals to the existing 4G LTE scenarios. It supports mMTC (Massive Machine Communication) scenario that requires low data rate and asynchronous access, and URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and supports high-speed mobility. .

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

<Normal NR system>

1 is a diagram schematically illustrating a structure of an NR system to which this embodiment can be applied.

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

gNB means a base station that provides NR user plane and control plane protocol termination to a terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal. The base station described in this specification should be understood as encompassing gNB and ng-eNB, and may be used as a meaning to distinguish gNB or ng-eNB as needed.

<NR Waveform, Pneumologic 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 MIMO (Multiple Input Multiple Output), and has advantages of using a low-complexity receiver with high frequency efficiency.

On the other hand, in NR, since the requirements for data rate, delay rate, coverage, etc. are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through the 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.

Specifically, the NR transmission numerology is determined based on sub-carrier spacing and cyclic prefix (CP), and the μ value is used as an exponential value of 2 based on 15 kHz as shown in Table 1 below. is changed to

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

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

Referring to FIG. 2 , a slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length in the time domain of the slot may vary according to a subcarrier interval. For example, in the case of a numerology having a 15 kHz subcarrier interval, the slot is 1 ms long and is configured with the same length as the subframe. On the other hand, in the case of numerology having a 30 kHz subcarrier interval, a slot consists 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 to have 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, NR defines a basic unit of scheduling as a slot, and also introduces a mini-slot (or a sub-slot or a non-slot based schedule) in order to reduce transmission delay in a radio section. When a wide subcarrier interval is used, the length of one slot is shortened in inverse proportion, so that transmission delay in a radio section can be reduced. The mini-slot (or sub-slot) is for efficient support of the URLLC scenario and can be scheduled in units of 2, 4, or 7 symbols.

Also, unlike LTE, NR defines uplink and downlink resource allocation at a symbol level within one slot. In order to reduce the HARQ delay, a slot structure capable of transmitting HARQ ACK/NACK directly within a transmission slot has been defined, and this slot structure will be described as a self-contained structure.

NR is designed to support a total of 256 slot formats, 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 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 transmission is scheduled to be distributed in one or more slots. Accordingly, the base station may 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 the table configured through UE-specific RRC signaling using SFI, and may indicate dynamically through Downlink Control Information (DCI) or statically or through RRC. It can also be ordered quasi-statically.

<NR Physical Resources>

In relation to a physical resource in NR, an antenna port, a resource grid, a resource element, a resource block, a bandwidth part, etc. are considered do.

An antenna port is defined such that a channel on which a symbol on an antenna port is carried can be inferred from a channel on which another symbol on the same antenna port is carried. When 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 QC/QCL) quasi co-location). Here, the wide range characteristic includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.

Referring to FIG. 3 , in the resource grid, since the NR supports a plurality of numerologies on the same carrier, a resource grid may exist according to each numerology. In addition, the resource grid may exist according to an antenna port, a subcarrier interval, and a transmission direction.

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

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

In NR, unlike LTE in which the carrier bandwidth is fixed at 20Mhz, 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 bandwidth part (BWP) may be designated within the carrier bandwidth and used by the terminal. In addition, the bandwidth part is associated with one numerology and is composed of a subset of continuous common resource blocks, and may be dynamically activated according to time. A maximum of four bandwidth parts are configured in the terminal, respectively, in uplink and downlink, and data is transmitted/received using the bandwidth part activated at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidth parts are set independently, and in the case of an unpaired spectrum, to prevent unnecessary frequency re-tunning between downlink and uplink operations For this purpose, the downlink and uplink bandwidth parts are set in pairs to share a center frequency.

<NR Initial Connection>

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

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

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

Referring to FIG. 5, the SSB consists of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, respectively, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

The terminal receives the SSB by monitoring the SSB in the time and frequency domains.

SSB can be transmitted up to 64 times in 5ms. A plurality of SSBs are transmitted using different transmission beams within 5 ms, and the UE performs detection on the assumption that SSBs are transmitted every 20 ms when viewed based on one specific 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 in 3 GHz or less, and SSB can be transmitted using up to 8 different beams in a frequency band of 3 to 6 GHz and up to 64 different beams in a frequency band of 6 GHz or more.

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 interval as follows.

On the other hand, the 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 in a place other than the center of the system band, and a plurality of SSBs may be transmitted in the frequency domain when broadband operation is supported. Accordingly, the UE monitors the SSB using a synchronization raster that is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are center frequency location information of the channel for initial access, are newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster, so that it can support fast SSB search of the terminal. can

The UE may acquire the MIB through the PBCH of the SSB. 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, the PBCH includes information on the position of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (eg, SIB1 neurology information, information related to SIB1 CORESET, search space information, PDCCH related parameter information), 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 neurology information is equally applied to some messages used in the random access procedure for accessing the base station after the terminal completes the cell search procedure. For example, the neurology information of SIB1 may be applied to at least one of messages 1 to 4 for the random access procedure.

The aforementioned RMSI may mean System Information Block 1 (SIB1), and SIB1 is periodically broadcast (eg, 160 ms) in the cell. SIB1 includes information necessary for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the UE to receive SIB1, it must receive neurology information used for SIB1 transmission and CORESET (Control Resource Set) information used for scheduling SIB1 through the PBCH. The UE checks scheduling information for SIB1 by using SI-RNTI in CORESET, and acquires SIB1 on PDSCH according to the scheduling information. SIBs other than SIB1 may be transmitted periodically or may be transmitted according to the request of the UE.

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

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

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), a UL grant (uplink radio resource), a temporary C-RNTI (Temporary Cell - Radio Network Temporary Identifier), and a Time Alignment Command (TAC). Since one random access response may include random access response information for one or more UEs, the random access preamble identifier may be included to inform which UE 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, RA-RNTI (Random Access - Radio Network Temporary Identifier).

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

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

<NR CORESET>

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

In this way, NR introduced the concept of CORESET in order to secure the flexibility of the system. 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. Quasi CoLocation (QCL) assumptions for each CORESET are set, and this is used for the purpose of notifying the characteristics of the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by the conventional QCL.

7 is a diagram 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 three OFDM symbols in the time domain. In addition, CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.

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 pieces of CORESET information through RRC signaling.

In the present specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals or various messages related to NR (New Radio) can be interpreted in various meanings used in the past or present or used in the future.

New Radio (NR)

As described above, NR conducted in 3GPP recently has a design that can satisfy various QoS requirements required for each subdivided and detailed usage scenario as well as an improved data rate compared to LTE. In particular, eMBB (enhancement Mobile BroadBand), mMTC (massive MTC), and URLLC (Ultra Reliable and Low Latency Communications) were defined as representative usage scenarios of NR. flexible) frame structure design is required. Each usage scenario has different requirements for data rates, latency, reliability, coverage, etc. Accordingly, as a method to efficiently satisfy the requirements for each usage scenario through the frequency band constituting an arbitrary NR system, different numerology (e.g. subcarrier spacing, subframe, TTI, etc.) based radio resource unit ( unit) is designed to multiplex efficiently.

For example, for numerology with different subcarrier spacing values, a discussion on how to support by multiplexing based on TDM, FDM, or TDM/FDM through one or multiple NR component carrier(s) lost. In addition, in configuring a scheduling unit in the time domain, a discussion has been made on a method of supporting one or more time units. In this regard, in NR, a subframe is defined as a type of time domain structure. As a reference numerology for defining the corresponding subframe duration, it was decided to define a single subframe duration composed of 14 OFDM symbols of the same 15 kHz Sub-Carrier Spacing (SCS)-based normal CP overhead as that of LTE. Accordingly, in NR, a subframe has a time duration of 1 ms. However, unlike LTE, the NR subframe is an absolute reference time duration, and slots and mini-slots may be defined as time units that are the basis of actual uplink/downlink data scheduling. In this case, the number of OFDM symbols constituting the slot, the y value, is determined to have a value of y=14 regardless of the SCS value in the case of normal CP.

Accordingly, an arbitrary slot consists of 14 symbols. In addition, all symbols may be used for DL transmission, or all symbols may be used for UL transmission, or may be used in the form of DL portion + (gap) + UL portion according to the transmission direction of the slot. have.

In addition, in any numerology (or SCS), a mini-slot composed of fewer symbols than the aforementioned slot is defined. A short time-domain scheduling interval for mini-slot-based uplink/downlink data transmission/reception may be configured, or a long time-domain scheduling interval for uplink/downlink data transmission/reception through slot aggregation may be configured. have. In particular, in the case of transmitting and receiving latency-sensitive data such as URLLC, it is difficult to satisfy the latency requirement if 1ms (14 symbols)-based slot-based scheduling defined in a numerology-based frame structure with a small SCS value such as 15kHz is performed. can Accordingly, scheduling that can satisfy the requirements of URLLC can be performed based on defining a mini-slot composed of fewer OFDM symbols than a slot composed of 14 symbols.

Meanwhile, in NR, the basic scheduling unit is changed to a slot. Also, regardless of subcarrier-spacing, the slot consists of 14 OFDM symbols. On the other hand, a non-slot structure composed of 2, 4, and 7 OFDM symbols, which is a smaller scheduling unit, is supported. The non-slot structure may be utilized as a scheduling unit for the URLLC service.

<LTE V2X Communication>

In the existing LTE system, a radio channel and radio protocol design for direct communication between terminals (ie, sidelink) was made to provide direct communication between terminals and V2X (particularly V2V) service.

In relation to the sidelink, PSS/SSS, which is a synchronization signal for synchronization between a wireless sidelink transmitter and a receiver, and a Physical Sidelink Broadcasting Channel (PSBCH) for transmitting and receiving a sidelink MIB (Master Information Block) related thereto are defined, and also discovery information PSDCH (Physical Sidelink Discovery channel) for transmission and reception, PSCCH (Physical Sidelink Control Channel) for transmission and reception of SCI (Sidelink Control Information), and PSSCH (Physical Sidelink Shared Channel) for transmitting and receiving sidelink data were designed.

In addition, for radio resource allocation for the sidelink, the technology was developed by dividing it into mode 1 in which the base station allocates radio resources and mode 2 in which the terminal selects and allocates radio resources from a pool. In addition, additional technological evolution was required in order to satisfy the V2X scenario in the LTE system.

By providing the vehicle with access to a cellular network (eg LTE or LTE-Advanced), the vehicle can be connected to the Internet and other vehicles. V2X (Vehicle to Everything) communication includes the following four types.

- V2V (Vehicle to Vehicle) Communication: Communication between vehicle and vehicle

- V2I (Vehicle to Infrastructure) Communication: Communication between vehicle and infrastructure

- V2N (Vehicle to Network) Communication: Communication between vehicle and network

- V2P (Vehicle to Pedestrian) Communication: Communication between vehicle and pedestrian

8 is a diagram exemplarily disclosed the architecture of the V2X communication system in the LTE system.

Referring to FIG. 8 , the V2X service may be provided through a PC5 interface and/or a Uu interface. Support via the PC5 interface was provided via V2X sidelink communication.

Specifically, the various V2X communication terminals (UEs A to D) are linked with a PC5 interface, and the V2X communication terminal and the V2X control function are linked with a V3 interface. In addition, the V2X application server and the V2X application of each V2X communication terminal are linked by the V1 interface. The V2X communication terminal is linked with the base station (E-UTRAN) with the Uu interface, and the base station is linked with the core network (MME and S/P GW) with the S1 interface. MME and S/P GW are linked with HSS and S6a interface, and HSS is linked with V2X control function and V4 interface. The core network entity is linked with the V2X application server and the SGi interface. On the other hand, the V2X application of each V2X communication terminal is linked to each other through the V5 interface.

The sidelink refers to the PC5 interface specified in 3GPP TS 23.303 as an interface between a terminal and a terminal.

In the conventional LTE system, resource allocation of a terminal supporting sidelink communication supports the following modes.

- Scheduled resource allocation: Requires an RRC connection for data transmission. The terminal requests transmission resource allocation to the base station, and the base station allocates sidelink control information (SCI) and transmission resources for data transmission. The terminal transmits the scheduling request and the subsequent sidelink BSR to the base station. The base station schedules transmission resources for sidelink communication using the configured SL-RNTI. For convenience of description, a resource allocation mode in which the base station allocates sidelink resources is referred to as a first mode. This is only for convenience of description and may be replaced with other names (sidelink Mode 1 for D2D, sidelink Mode 3 for V2X).

- UE autonomous resource allocation: UE selects a resource by itself from within a pre-configured sidelink resource pool, and selects a transmission format for transmitting sidelink control information and data. When a resource pool is selected, the selection is valid for the entire sidelink control period. When the corresponding period ends, the UE may perform resource pool selection again. For convenience of explanation, a resource allocation mode in which the terminal selects a sidelink resource according to a predetermined criterion in the sidelink resource pool is denoted as the second mode (sidelink Mode 2 for D2D, sidelink Mode 4 for V2X). do. This is only for convenience of description and may be replaced with another name.

In D2D communication such as public safety, the same resource allocation structure is shared in both modes (mode 1, mode 2). Data transmission is scheduled within the PSCCH period. Within this period, a set of subframes is used for PSCCH (Physical Sidelink Control CHannel) transmission. Another set of subframes is used for PSSCH transmission. PSCCH including scheduling control information for one corresponding PSSCH (Physical Sidelink Shared CHannel) is always transmitted before PSSCH data.

In V2X communication, in order to allocate PSCCH and PSSCH in two modes (mode 3, mode 4), a resource allocation structure completely different from the two modes (mode 1, mode 2) of D2D communication is used. First, there is no PSCCH period so that two physical channels (PSCCH and PSSCH) can be distributed and transmitted at different periods. The PSCCH and the PSSCH are separated in the frequency domain. In SCI format 1, two identical SCIs and a corresponding PSSCH transport block may be transmitted in the same subframe. A transport block may be transmitted once or twice. When transmitted twice, the receiver provides combining for the redundant version of the PSSCH transport block.

For sidelink communication when the terminal is out of coverage, a set of transmission/reception resource pools for sidelink control information may be preconfigured in the terminal. A set of transmission/reception resource pools for sidelink data information may be preconfigured in the terminal. In order to perform sidelink communication even when some UEs are in coverage and some UEs are out of coverage, all UEs are from a serving cell, a neighboring cell, and out of coverage (i.e. pre-configured transmission resource pools). For transmission of sidelink control information, a resource pool for receiving sidelink control information should be configured as a union of all used resource pools. Accordingly, power consumption was large for the terminal to receive the sidelink control information.

Meanwhile, the autonomous resource allocation terminal performs sensing for (re)selection of sidelink resources. The UE (re)selects some specific sidelink resources. And reserve a plurality of sidelink resources. Up to two parallel independent resource reservation processes may be allowed to be performed in the terminal. The UE is allowed to perform single resource selection for V2X sidelink transmission. A terminal using scheduled resource allocation may be configured to perform sensing. In addition, the sensing result can be periodically reported. The UE may perform sensing only in the sidelink transmission resource pool configured for reporting.

The resource pool for transmission of the pedestrian terminal (pedestrian UR) may overlap with the resource pool for V2X sidelink communication. A resource selection mechanism may be configured for each transport pool. For example, at least one of random selection and partial sensing-based selection may be configured. If configured to use only partial sensing-based selection, the UE may use partial sensing-based selection in a specific resource pool.

NR V2X/NR Sidelink

3GPP approved the NR V2X item to support advanced V2X services such as vehicles platooning, extended sensors, advanced driving, and remote driving based on NR in Rel-16. NR V2X is not intended to replace the service provided by LTE V2X, and it is assumed to supplement LTE V2X for improved V2X service and support interworking with LTE V2X. Accordingly, unlike LTE V2X, which provides broadcast-based V2X basic service, NR V2X includes support for unicast mode and groupcast mode.

In NR V2X, the resource allocation method is a scheduled resource allocation (mode 1) in which the base station performs scheduling for communication resources between terminals, and a terminal autonomous resource selection (mode 2) method in which the terminal autonomously selects a resource from a resource pool. This can be supported.

In the scheduled resource allocation mode, the base station schedules transmission resources for sidelink communication through the SL-RNTI on the PDCCH. In addition, the base station can allocate sidelink resources with two types of configured sidelink grants. Type 1 provides a sidelink grant configured directly by RRC. Type 2 defines the cycle of a sidelink configured with RRC and may activate or deactivate a sidelink grant configured with PDCCH. For NR sidelink communication, the PDCCH is addressed to the SL-CS-RNTI.

In order for the receiving terminal to receive and demodulate the PSSCH, sidelink control information (SCI) is used. SCI may consist of two parts. First, it can be divided into a first-stage SCI carried on the PSCCH (e.g. SCI format 1-A) and a second-stage SCI carried on the PSSCH.

SCI format 1-A is used for second-stage SCI scheduling transmitted on PSSCH and PSSCH and may include at least one of the following information.

- Priority (Priority), frequency resource assignment (Frequency resource assignment), Time resource assignment, resource reservation period, DMRS pattern, 2nd-stage SCI format, Beta_offset indicator, Number of DMRS port, Modulation and coding scheme, Additional MCS table indicator, PSFCH overhead indication

The second stage SCI is divided into SCI format 2-A and SCI format 2-B.

SCI format 2-A may include at least one of the following information.

- HARQ process number (HARQ process number/ID), New data indicator, Redundancy version, Source ID, Destination ID, HARQ feedback enable/disable indicator, Cast type indicator, CSI request

SCI format 2-B may include at least one of the following information.

- HARQ process number (HARQ process number/ID), New data indicator, Redundancy version, Source ID, Destination ID, HARQ feedback enable/disable indicator, Zone ID, communication range requirement

Meanwhile, in the terminal autonomous resource selection mode, the terminal may temporarily use the terminal autonomous resource selection with random selection for sidelink transmission based on the configuration of the exception transmission resource pool. Even for NR V2X, the receiving terminal had a burden of continuously monitoring the sidelink reception resource pool in all resource pools for sidelink communication.

In this regard, in order to reduce the power consumption of the terminal on the sidelink, it may be considered to apply the DRX function. However, no specific method was provided for this. In particular, since SCI is transmitted including DCI and other additional information transmitted on the Uu interface between the terminal and the base station, consideration for this may be necessary to provide the sidelink DRX, but no specific method has been presented.

In addition, in the sidelink interface between the terminal and the terminal, unlike the Uu interface between the terminal and the base station, the terminal performs transmission and reception by switching with another terminal through one sidelink carrier, or the terminal performs transmission and reception with the other terminal It can be done by switching. Therefore, when applying the sidelink DRX function for sidelink reception to the terminal, it may be desirable to consider the operation on the sidelink transmission function, but a specific method has not been presented for this.

As such, in the conventional V2X communication technology, the DRX function for reducing terminal power consumption in the transmission/reception process of the sidelink terminal is not provided. The present disclosure devised to solve this problem proposes a DRX operation method and apparatus for power-efficiently transmitting and receiving data in consideration of SCI between sidelink communication terminals. In addition, we propose a method and apparatus for power-efficiently providing a sidelink transmission to a terminal in connection with a sidelink DRX function.

The embodiment provided below may be applied to sidelink communication between an NR terminal and an NR terminal through an NR base station. Of course, the embodiment provided below may also be applied to sidelink communication between an NR terminal and an LTE terminal through an NR base station. Alternatively, the embodiment provided below may be applied to sidelink communication between an LTE terminal and an LTE terminal through an NR base station. Alternatively, the embodiment provided below may be applied to sidelink communication between an LTE terminal and an LTE terminal through an LTE base station. Alternatively, the embodiment provided below may be applied to sidelink communication between an LTE terminal and an NR terminal through an LTE base station. Alternatively, the embodiment provided below may be applied to sidelink communication between an NR terminal and an NR terminal through an LTE base station.

Meanwhile, the embodiments provided below may be applied to an LTE terminal connected to an eLTE base station connected through a 5G system (or 5G Core Network). Alternatively, the embodiment provided below may be applied to an E-UTRAN NR Dual Connectivity (EN-DC) terminal or an NR E-UTRAN Dual Connectivity (NE-DC) terminal that simultaneously provides LTE and NR wireless connectivity.

In the base station, any base station among the master base station or the secondary base station may indicate configuration information for sidelink communication. For convenience of description, the following description is mainly based on unicast V2X communication. This is for convenience of description, and the present embodiment may be applied to a groupcast or broadcast method. In addition, this embodiment can be applied to sidelink-based V2X communication as well as sidelink-based arbitrary applications (e.g. Public safety, IoT, commercial D2D). For example, it can be applied to a terminal having any capability related to Sidelink as well as a V2X capable terminal and a V2P capable terminal.

A terminal in the present specification means a device capable of performing sidelink communication. The base station may mean a transmission/reception point that has an RRC connection with the terminal. In addition, the other terminal means another terminal for performing sidelink communication with the terminal serving as the description standard in this specification, and there is no limitation on terms. That is, the other terminal can be described as a peer terminal in that it performs sidelink communication with a reference terminal. In addition to this, it may be described in various terms.

9 is a diagram for explaining an operation of a terminal according to an embodiment.

Referring to FIG. 9 , a terminal performing sidelink communication may perform a step of receiving a sidelink RRC (Radio Resource Control) message from a base station or another terminal (S900).

For example, the terminal may receive a sidelink RRC message from the base station. The sidelink RRC message may be a sidelink RRC reconfiguration message. The sidelink RRC message may include information for configuring sidelink or sidelink DRX in the terminal.

As another example, the terminal may receive a sidelink RRC message from another terminal. The sidelink RRC message may be a sidelink RRC reconfiguration message. The sidelink RRC message may include information for configuring sidelink or sidelink DRX in the terminal. Here, the other terminal may mean a terminal peering with the terminal to perform or to perform sidelink communication. Alternatively, the other terminal may be a terminal for controlling sidelink communication of the terminal.

The terminal may perform a step of configuring a sidelink discontinuous reception (DRX) parameter using information included in the sidelink RRC message (S910).

For example, the sidelink RRC message may include a sidelink DRX parameter. The sidelink DRX parameter may include one or more pieces of information necessary for the UE to perform a DRX operation in the process of performing sidelink communication.

As an example, the sidelink DRX parameter may include a sidelink DRX CSI timer for receiving sidelink channel status information (CSI). As another example, the sidelink DRX parameters include sidelink DRX duration timer, sidelink DRX slot offset, sidelink DRX cycle, sidelink DRX start offset, sidelink DRX inactivity timer, sidelink reception DRX HARQ RTT timer, sidelink DRX inactivity timer, which will be described later. At least one of a link reception DRX retransmission timer and a sidelink transmission DRX retransmission timer may be further included. As another example, the sidelink DRX parameter may include a sidelink DRX resource reservation timer.

As such, the sidelink RRC message may include various information necessary for the terminal to perform a sidelink DRX operation. Specific parameters and parameter use operations will be described separately for each embodiment in more detail below.

Meanwhile, the sidelink DRX CSI timer may be set to start in connection with transmission of sidelink control information including a request for sidelink channel state information to another terminal. That is, the UE may configure a sidelink DRX CSI timer by receiving the sidelink RRC message, and may associate the start of the sidelink DRX CSI timer with the operation of transmitting the sidelink CSI request.

In addition, the sidelink DRX CSI timer may be set to expire when at least one event of receiving sidelink channel state information from another terminal and reaching a delay time range set for a sidelink channel state information report is satisfied. For example, when the sidelink channel state information is received while the sidelink DRX CSI timer is running, the UE may terminate (expire) the sidelink DRX CSI timer. Alternatively, the UE may terminate (expire) the sidelink DRX CSI timer when the delay time range set for the sidelink channel state information is reached when the sidelink DRX CSI timer is in operation.

The terminal may perform a step of monitoring reception of sidelink data using the sidelink DRX parameter (S920).

For example, the UE may configure sidelink DRX parameters and monitor sidelink data discontinuously in performing sidelink communication. Accordingly, a response to the sidelink channel state information according to the request for sidelink channel state information should be made when the terminal performs sidelink data monitoring.

Accordingly, the UE performs an operation of monitoring the sidelink control information while the sidelink DRX CSI timer is operating.

Through the above-described operation, the terminal can smoothly perform the sidelink DRX operation, and unnecessary power consumption of the terminal can be prevented. In addition to this, the UE may perform operations for resource reservation, resource selection, and the like in a sidelink DRX operation situation. Such an operation will be described in more detail by dividing for each embodiment below.

10 is a diagram for explaining an operation of another terminal according to an embodiment.

Referring to FIG. 10 , another terminal performing sidelink communication may perform a step of transmitting a sidelink RRC (Radio Resource Control) message to the terminal (S1000).

As described above, the sidelink RRC message may be transmitted by the base station, but a case in which the sidelink RRC message is transmitted by another terminal will be mainly described herein. If the base station transmits the sidelink RRC message, other terminals may also receive the corresponding RRC message from the base station.

The sidelink RRC message may be a sidelink RRC reconfiguration message. The sidelink RRC message may include information for configuring sidelink or sidelink DRX in the terminal. Here, the other terminal may mean a terminal peering with the terminal to perform or to perform sidelink communication. Alternatively, the other terminal may be a terminal for controlling sidelink communication of the terminal.

The other terminal may perform a step of receiving a request for sidelink channel status information (CSI) from the terminal (S1010).

Another terminal may receive a request message for requesting sidelink CSI from the terminal. The request message may be included in the sidelink control information. When the other terminal receives the sidelink CSI request, it measures channel state information according to the request.

The other terminal may perform a step of controlling the terminal to transmit sidelink channel state information while the sidelink DRX CSI timer is operating (S1020).

For example, the sidelink RRC message may include a sidelink DRX parameter. The sidelink DRX parameter may include one or more pieces of information necessary for the UE to perform a DRX operation in the process of performing sidelink communication.

For example, the sidelink DRX parameter may include a sidelink DRX CSI timer for the UE to receive sidelink channel status information (CSI). As another example, the sidelink DRX parameters include sidelink DRX duration timer, sidelink DRX slot offset, sidelink DRX cycle, sidelink DRX start offset, sidelink DRX inactivity timer, sidelink reception DRX HARQ RTT timer, sidelink DRX inactivity timer, which will be described later. At least one of a link reception DRX retransmission timer and a sidelink transmission DRX retransmission timer may be further included. As another example, the sidelink DRX parameter may include a sidelink DRX resource reservation timer.

As such, the sidelink RRC message may include various information necessary for the terminal to perform a sidelink DRX operation. Specific parameters and parameter use operations will be described separately for each embodiment in more detail below.

Meanwhile, the sidelink DRX CSI timer may be set so that the terminal starts in connection with transmission of sidelink control information including a request for sidelink channel state information to another terminal. That is, the UE may configure a sidelink DRX CSI timer by receiving the sidelink RRC message, and may associate the start of the sidelink DRX CSI timer with the operation of transmitting the sidelink CSI request.

In addition, the sidelink DRX CSI timer may be set to expire when at least one event of receiving sidelink channel state information from another terminal and reaching a delay time range set for a sidelink channel state information report is satisfied. For example, when the sidelink channel state information is received while the sidelink DRX CSI timer is running, the UE may terminate (expire) the sidelink DRX CSI timer. Alternatively, the UE may terminate (expire) the sidelink DRX CSI timer when the delay time range set for the sidelink channel state information is reached when the sidelink DRX CSI timer is in operation.

Accordingly, the other terminal may measure the channel state according to the sidelink CSI request received from the terminal, and transmit the measurement result during a time period in which the sidelink DRX CSI timer configured in the terminal is operating. For example, the UE may configure sidelink DRX parameters and monitor sidelink data discontinuously in performing sidelink communication. Accordingly, a response to the sidelink channel state information according to the request for sidelink channel state information should be made when the terminal performs sidelink data monitoring.

Through this operation, even when DRX is applied to communication between terminals, sidelink communication such as CSI transmission/reception can be smoothly performed.

Each of the embodiments described below may be implemented individually or in any combination.

How to control sidelink DRX operation in consideration of 2nd stage SCI reception

If the sidelink DRX configuration for controlling the sidelink DRX operation is indicated and applied by the base station when the terminal is in the RRC connected state, the terminal is applied to all (or one or more) sidelink carriers (or all activated sidelinks). For a link carrier, or for all configured sidelink carriers), it may cause the MAC entity to receive the PSCCH (or SCI) discontinuously.

Alternatively, even if the terminal is in the RRC IDLE / RRC inactive state, if the sidelink DRX configuration is preconfigured or the corresponding system information is received by the base station, the terminal is configured for all (or one or more) sidelink carriers (or all active side For a link carrier, or for all configured sidelink carriers), it may cause the MAC entity to receive the PSCCH (or SCI) discontinuously.

Or, in an RRC state, when a sidelink DRX configuration is indicated and applied through a sidelink RRC reconfiguration message (RRCReconfigurationSidelink) from the other terminal to the terminal, the terminal is configured for all (or one or more) sidelink carriers (or all activations) sidelink carrier, or for all configured sidelink carriers), the MAC entity may receive the PSCCH (or SCI) non-contiguously.

If it is not the case described above, the UE may continuously monitor the PSCCH (or SCI).

As described above, the SCI may be divided into two stages and indicated to the UE. The terminal to which the sidelink DRX configuration is applied may receive/monitor the PSCCH in active time.

For example, if the UE receives SCI on the PSCCH, the UE needs to receive/monitor the ^2nd stage SCI on the PSSCH in order to distinguish/identify the corresponding DRX configuration. The terminal includes at least one of HARQ process number (HARQ process number/ID), New data indicator, Redundancy version, Source ID, Destination ID, HARQ feedback enable/disable indicator, Cast type indicator and CSI request included in the ^2nd stage SCI. It is possible to distinguish/identify the corresponding DRX configuration through .

For the sidelink unicast mode, the sidelink DRX configuration can be configured per pair of source (origin) and destination pairs. A terminal that has sent the DRX configuration in out-of-coverage may determine the DRX configuration. For the sidelink unicast mode, a plurality of DRX configurations may be indicated and applied to the terminal.

For the sidelink groupcast and broadcast modes, the sidelink DRX configuration may be configured through one common configuration information. In the in-coverage RRC idle/RRC inactive/RRC connection, the transmitting terminal and the receiving terminal may acquire the DRX configuration through the SIB. In the out-of-coverage, the transmitting terminal and the receiving terminal may acquire the DRX configuration through pre-configuration. For the sidelink groupcast and broadcast modes, a plurality of DRX configurations may be indicated and applied to the terminal.

The source L2 ID identifies the sender of the data in the NR sidelink communication. The source L2 ID is 24 bits long and is split into two bit strings at the MAC layer. The first bit string is forwarded to the sender's physical layer as the LSB part (8 bits) of the source L2 ID. The first bit string identifies the source of the intended data in the sidelink control information (SCI). And the first bit string is used for packet filtering in the physical layer of the receiver. The second bit string is carried in the MAC header as the MSB part (16 bits) of the source L2 ID. The second bit string is used for packet filtering in the MAC layer of the receiver.

The destination L2 ID identifies the target of the data in the NR sidelink communication. The destination L2 ID has a length of 24 bits and is divided into two bit strings at the MAC layer. The first bit string is forwarded to the sender's physical layer as the LSB part (16 bits) of the destination L2 ID. The first bit string identifies a target of intended data in sidelink control information (SCI). And the first bit string is used for packet filtering in the physical layer of the receiver. The second bit string is carried in the MAC header as the MSB part (8 bits) of the destination L2 ID. The second bit string is used for packet filtering in the MAC layer of the receiver.

For another example, if the UE receives SCI on the PSCCH, the UE needs to receive/monitor the ^2nd stage SCI on the PSSCH in order to distinguish/identify the corresponding DRX configuration. Alternatively, the UE needs to receive/monitor the ^2nd stage SCI in order to decode/process the PSSCH.

One or more DRX configurations may be indicated and applied for each cast type for an arbitrary terminal. Alternatively, for sidelink unicast, the sidelink DRX configuration may be configured for each pair of source and destination. Alternatively, one or more sidelink DRX configurations may be indicated and applied for a pair of source and destination for sidelink unicast. ^2nd stage SCI information may be received/monitored/decoded on ^PSSCH through 1st stage SCI information. Through the information included in the ^2nd stage SCI, the UE can control the operation of the DRX parameter applied through the corresponding DRX configuration.

The sidelink DRX parameter may include one or more of the following parameters.

o Sidelink discontinuous reception (DRX) on-duration timer: indicates duration information at the start of the DRX cycle in the sidelink.

o Sidelink DRX (slot) offset: indicates a delay before starting the sidelink DRX on-duration timer. For example, the sidelink DRX on-duration timer may be started at a fixed offset time (after) from a specific time based on the sync source of the UE.

o Sidelink DRX cycle: Indicates sidelink DRX cycle information. A sidelink Long/Short DRX cycle may be included. The short DRX cycle may or may not be used selectively, and only the Long DRX cycle may be used.

o Sidelink DRX start offset: indicates offset information defining a subframe/slot where the sidelink DRX cycle starts.

o Sidelink discontinuous reception inactivity timer: indicates duration information after PSCCH / PSSCH omission (or PSCCH / PSSCH period or PSCCH / PSSCH reception time) in which SCI indicates sidelink transmission to a new corresponding terminal for the MAC entity do. Alternatively, the PSCCH indicates duration information after the PSCCH omission (or PSCCH/SCI reception time) indicating new sidelink transmission for the MAC entity. Alternatively, ^2nd SCI on the PSSCH for the MAC entity indicates duration information after a PSSCH occupancy (or PSSCH period or PSSCH reception time) indicating new sidelink transmission.

o Sidelink reception discontinuous reception HARQ RTT timer (referred to as drx-HARQ-RTT-TimerRX-SL for convenience of description): Indicates minimum duration information until reception SCI for HARQ retransmission is expected by the MAC entity. The corresponding timer may be operated for each SL reception HARQ process.

o Sidelink transmission non-continuous reception HARQ RTT timer (referred to as drx-HARQ-RTT-TimerTX-SL for convenience of explanation): A grant for transmission HARQ retransmission by the MAC entity [or SCI (for example, if scheduling from the UE) ) or DCI (for example, if scheduling is instructed by the base station)] indicates minimum duration information until expected. The corresponding timer may be operated for each SL transmission HARQ process.

o Sidelink reception discontinuous reception retransmission timer (represented as drx-RetransmissionTimerRX-SL for convenience of explanation): indicates the maximum duration information until sidelink retransmission is received. The corresponding timer may be operated for each SL reception HARQ process.

o Sidelink transmission non-continuous reception retransmission timer (represented as drx-RetransmissionTimerTX-SL for convenience of explanation): Grant for sidelink retransmission [or SCI (eg, if scheduling is instructed from the UE) or DCI (eg For example, if scheduling is instructed by the base station)], it indicates the maximum duration information until received. The corresponding timer may be operated for each SL transmission HARQ process.

When the sidelink DRX cycle is configured, the active time for the sidelink carrier(s)/resource pool(s) (within one DRX group) may be defined including one or more of the following.

- When sidelink DRX on-duration timer or sidelink DRX inactivity timer is running

- When sidelink transmission DRX retransmission timer or sidelink reception DRX retransmission timer is running

If any sidelink DRX parameters are configured, the terminal (MAC entity) may operate as follows for the corresponding DRX configuration.

1> If DRX configuration/DRX group is in active time,

2> Monitor PSCCH/SCI in the corresponding DRX configuration/DRX group. Alternatively, the 1st stage SCI on PSCCH and/or the 2nd stage SCI on PSSCH are monitored.

2> If PSCCH / SCI indicates (new) sidelink transmission (or, if 1 ^st stage SCI on PSCCH and 2 ^nd stage SCI on PSSCH indicate (new) sidelink transmission for the corresponding terminal, 2 ^nd One of including the source/destination L1 ID that the terminal intends to receive (intended) through stage SCI, including the source/destination L2 ID that the terminal intends to receive (intended) on the MAC header, and including the cast type that the terminal intends to receive if the above is satisfied)

3> Start/restart the sidelink DRX inactivity timer in the first symbol after the end of the PSSCH (eg the last PSSCH symbol). Alternatively, the sidelink DRX inactivity timer is started/restarted in the first symbol after the end of the PSSCH including the ^2nd stage SCI. Alternatively, the sidelink DRX inactivity timer is started/restarted in the first symbol after the end of the PSCCH.

1> If the sidelink DRX inactivity timer expires:

2> PSCCH/SCI can be monitored non-continuously. Alternatively, PSCCH monitoring may be skipped. Alternatively, SCI monitoring may be skipped. Alternatively, 1 ^st stage SCI on PSCCH and 2 ^nd stage SCI on PSSCH monitoring may be skipped.

1> [(SFN Х 10) + subframe number] modulo (sidelink drx-Cycle) = sidelink drx-StartOffset

2> Start sidelink DRX on-duration timer after sidelink DRX slot offset from the start of the subframe. (start sidelink drx-onDurationTimer after drx-SlotOffset from the beginning of the subframe.)

How to define parameters for controlling sidelink DRX operation according to CSI request

The sidelink CSI reporting procedure is used to provide sidelink channel state information to the counterpart terminal. For convenience of description, a case in which the sidelink transmitting terminal receives the CSI report from the sidelink receiving terminal will be described. The transmitting terminal may indicate the delay time range (sl-LatencyBoundCSI-Report) for the sidelink CSI report to the receiving terminal through a sidelink RRC reconfiguration message (RRCReconfigurationSidelink). For example, the delay time range may be configured within 3 to 160 slots. If the receiving terminal receives the CSI request, the corresponding receiving terminal may measure the sidelink CSI within the configured delay time range and transmit the measurement result (sidelink CSI report) to the transmitting terminal that has transmitted the CSI request. When the transmitting terminal transmits a CSI request to the receiving terminal through SCI, the transmitting terminal can expect to receive the CSI reporting from the receiving terminal within the aforementioned delay time range. If sidelink DRX is operated in the transmitting terminal, and if the time at which the receiving terminal wants to transmit the CSI reporting corresponds to the sidelink DRX inactive time of the transmitting terminal, even if the receiving terminal transmits the CSI reporting, the transmitting terminal cannot receive it. To prevent this, you can use the following methods.

For example, when a transmitting terminal operating sidelink DRX transmits an SCI including a CSI request to a receiving terminal, the transmitting terminal may define a timer for including as an active time on the sidelink DRX and start it. For convenience of description, this is denoted as a sidelink DRX CSI timer. This is only for convenience of description and may be replaced with any other name.

When the transmitting terminal transmits the SCI including the CSI request to the receiving terminal (the MAC entity receiving it from the physical layer) starts/restarts the sidelink DRX CSI timer. If it is desired to set a specific period/duration/offset for CSI measurement, the corresponding timer may be started/restarted after the period/duration/offset. When the transmitting terminal receives the CSI reporting (CSI response), the transmitting terminal may stop the sidelink DRX CSI timer. For example, upon receiving the sidelink CSI reporting MAC CE, the transmitting terminal may stop the sidelink DRX CSI timer. The sidelink DRX CSI timer may have the same value as the delay time range for the sidelink CSI report described above. While the sidelink DRX CSI timer is running, it may be included in the active time for monitoring the PSCCH (or SCI).

For another example, if the transmitting terminal operating sidelink DRX transmits SCI including the CSI request to the receiving terminal, the receiving terminal reports sidelink CSI (e.g. sidelink CSI) according to an arbitrary active time on the sidelink DRX of the transmitting terminal. Reporting MAC CE) may be transmitted. For example, the receiving terminal may transmit sidelink CSI reporting (e.g. sidelink CSI reporting MAC CE) while the sidelink DRX duration timer (or sidelink DRX inactivity timer) (of the transmitting terminal) is operating.

If the sidelink CSI reporting is triggered by the SCI and is not canceled, if the receiving terminal (the MAC entity of the receiving terminal) has a sidelink resource allocated for new transmission, and the corresponding sidelink resource is any of the transmitting / counterpart terminal Corresponds to the active time of , and if the sidelink shared channel (SL-SCH) resource can accommodate the sidelink reporting MAC CE and its subheader, if it has the sidelink resource, to generate the sidelink CSI reporting MAC CE Instructs the Multiplexing and Assembly procedure. If the resource does not correspond to any active time of the transmitting/counter terminal, a CSI reporting MAC CE can be generated and transmitted to the transmitting/counter-terminal at a time belonging to an arbitrary active time before the sidelink CSI report timer expires. have.

How to operate a CSI request in conjunction with a sidelink DRX parameter

When the receiving terminal in which the sidelink DRX operates is expected to transmit PSCCH/PSSCH through the resource reserved by the transmitting terminal, it is preferable to maintain the active time. To this end, the receiving terminal waits for the CSI reporting reception according to the CSI request for the corresponding sidelink carrier (cell/PC-5 RRC connection/cast type) in one sidelink DRX configuration (or sidelink DRX group). It can be processed in conjunction with the sidelink DRX timer included in the active time.

When a sidelink DRX cycle is configured, the active time for a sidelink carrier/cell/PC-5 RRC/cast type in one sidelink DRX configuration (or sidelink DRX group) may include one or more of the following times: can

- while the sidelink DRX on-duration timer is running

- while the sidelink DRX inactivity timer is running

- while sidelink DRX retransmission timer is running

Hereinafter, a method for processing in connection with the sidelink DRX inactivity timer will be described. This is only for convenience of description, and processing in conjunction with any sidelink DRX timer included in the above-described active time is also included in the scope of this embodiment.

When the UE transmits the SCI including the CSI request to the counterpart UE, the MAC entity of the UE instructing the UE to transmit the SCI including the CSI request from the physical layer starts/restarts the sidelink DRX inactivity timer. For example, if the PSCCH/CSI including the CSI request is transmitted, the UE starts/restarts the sidelink DRX inactivity timer in the first symbol after the end of the PSCCH transmission. For another example, if PSCCH/CSI including a CSI request is transmitted, the UE starts/restarts the sidelink DRX inactivity timer at the first symbol after a specific period/duration/offset after the end of PSCCH transmission.

How to define parameters for controlling sidelink DRX operation according to resource reservation

While the receiving terminal performs the DRX function for sidelink reception, when the transmitting terminal that has set up a PC5-RRC connection to the terminal operates in the terminal autonomous resource allocation mode (resource allocation second mode), the transmitting terminal performs some specific Sidelink resources can be (re)selected. In addition, a plurality of sidelink resources may be reserved. Resource reservation provides the effect of reducing the possibility of collision when performing sidelink communication.

For each transport pool, a resource selection mechanism may be configured. For example, one of random selection, partial sensing-based selection, and full sensing-based selection may be configured. In order for the transmission data of the (transmitting) terminal to be received by the other (receiving) terminal in which the DRX function is operating using the reserved resource, the resource reserved by the (transmitting) terminal is the active time of the counterpart (receiving) terminal. included in the data must be transmitted. If sidelink DRX is operated in the receiving terminal, and the time corresponding to the resource reserved by the transmitting terminal corresponds to the sidelink DRX inactive time of the receiving terminal, the transmitting terminal transmits the PSCCH/PSSCH using the reserved resource. Even if it is transmitted, the receiving terminal cannot receive it. To prevent this, you can use the following methods.

For example, when a receiving terminal in which sidelink DRX operates is expected to transmit PSCCH/PSSCH through a resource reserved by the transmitting terminal, it may define a timer to be included as an active time on the sidelink DRX and start it. For convenience of description, this is denoted as a sidelink DRX resource reservation timer. This is only for convenience of description and may be replaced with any other name.

First, it will be described from the perspective of the transmitting terminal. If the transmitting terminal (the MAC entity of the transmitting terminal) has selected to generate a selected sidelink grant corresponding to a plurality of MAC PDUs, and sidelink data is available in one logical channel, the transmitting terminal is the selected resource allowed for that logical channel. If you do not have a pool, choose a resource pool. The transmitting terminal may perform a TX resource (re)selection check on the selected resource pool. If TX resource (re)selection is triggered as a result of the TX resource (re)selection check, the transmitting terminal selects an allowed value configured by RRC in the sidelink resource reservation period list. In addition, the transmitting terminal may set the resource reservation interval to a selected value. The transmitting terminal may randomly select time and frequency resources from the resources indicated by the physical layer. Alternatively, the transmitting terminal may randomly select time and frequency resources for one transmission opportunity from the resources indicated by the physical layer. Alternatively, the transmitting terminal may randomly select time and frequency resources for one or more transmission opportunities from available resources according to the selected time/frequency resource. A randomly selected resource may be used to select a set of periodic resources spaced by a resource reservation interval for transmission of the PSCCH and PSSCH corresponding to the number of transmission opportunities of the MAC PDU. The transmitting terminal transmits the SCI including the resource reservation period/interval.

Next, it will be described from the viewpoint of the receiving terminal. When the transmitting terminal transmits the SCI including the resource reservation period to the receiving terminal (the receiving terminal (the MAC entity of the receiving terminal) that has received it from the physical layer) starts/restarts the sidelink DRX resource reservation timer. If it is desired to set a specific period/duration/offset for starting/restarting the resource reservation timer, the corresponding timer may be started/restarted after the period/duration/offset. Alternatively, the sidelink DRX resource reservation timer may be started/restarted after a certain period/duration/offset/number of slots in the resource reservation period. The corresponding period/duration/offset/slot number may be set to a value less than the resource reservation period. If the transmitting terminal transmits an SCI that does not include a resource reservation period (or an SCI with a resource reservation period of 0 or without resource reservation) to the receiving terminal, (the receiving terminal (the MAC entity of the receiving terminal) that has received it from the physical layer Stop the sidelink DRX resource reservation timer. If the transmitting terminal does not transmit the PSCCH/PSSCH in the next resource reservation period, the receiving terminal (the MAC entity of the receiving terminal) stops the sidelink DRX resource reservation timer. While the sidelink DRX resource reservation timer is running, it may be included in the active time for monitoring the PSCCH (or SCI).

For another example, when the transmitting terminal transmits the SCI including the resource reservation period to the receiving terminal, the transmitting terminal may determine the resource reservation period according to a period in which an arbitrary active time arrives on the sidelink DRX of the receiving terminal. For example, the transmitting terminal may determine and transmit the resource reservation period with the same value as the DRX cycle or an arbitrary multiple value.

How to operate in connection with the sidelink DRX parameter when the resource reservation period is received

When the receiving terminal in which the sidelink DRX operates is expected to transmit PSCCH/PSSCH through the resource reserved by the transmitting terminal, it is preferable to maintain the active time. To this end, the receiving terminal sets the resource reservation period in one sidelink DRX configuration (or sidelink DRX group) to the sidelink DRX timer included in the active time for the corresponding sidelink carrier (cell/PC-5 RRC connection/cast type). can be dealt with in connection with

When a sidelink DRX cycle is configured, the active time for a sidelink carrier/cell/PC-5 RRC/cast type in one sidelink DRX configuration (or sidelink DRX group) may include one or more of the following times: can

- while the sidelink DRX on-duration timer is running

- while the sidelink DRX inactivity timer is running

- while sidelink DRX retransmission timer is running

Hereinafter, a method for processing in connection with the sidelink DRX inactivity timer will be described. This is only for convenience of description, and processing in association with any sidelink DRX timer included in the active time is also included in the scope of this embodiment.

When the transmitting terminal transmits the SCI including the resource reservation period to the receiving terminal, the receiving terminal (the MAC entity of the receiving terminal) that has received the resource reservation period from the physical layer starts/restarts the sidelink DRX inactivity timer. For example, if the PSCCH indicates a new transmission, the receiving terminal starts/restarts the sidelink DRX inactivity timer in the first symbol after the end of PSCCH reception. For another example, if the PSCCH indicates a resource reservation period (or a non-zero resource reservation period), the receiving terminal starts/restarts the sidelink DRX inactivity timer in the next resource reservation period/interval. For another example, if the PSCCH indicates a resource reservation period (or a non-zero resource reservation period), the receiving terminal first (or nth, n is an arbitrary natural number) before the next resource reservation period/interval after the end of PSCCH reception may be indicated or preconfigured) Start/restart the sidelink DRX inactivity timer in the symbol.

Through the above operation, sidelink communication can be performed power-efficiently. Meanwhile, various embodiments for performing sidelink communication in a power efficient manner will be described below. The embodiments described below may be implemented independently or in any combination with the above-described embodiments.

Define sidelink DRX parameters and default behavior

The sidelink DRX parameter may include various information and detailed parameters as described above. Specific sidelink DRX parameters are omitted as described above.

When sidelink DRX is configured, the MAC entity may operate as follows.

1> If one MAC PDU is transmitted in one configured sidelink grant:

2> Start the sidelink reception drx-HARQ-RTT-Timer for the corresponding HARQ process. In this case, the time may be the first symbol after the end of the first repetition of the corresponding PSSCH (or PSCCH) transmission. Alternatively, it may be the first symbol after the end of the corresponding PSSCH (or PSCCH) transmission. or any point in time.

2> Stop the sidelink reception drx-RetransmissionTimer for the corresponding HARQ process.

1> If sidelink receive drx-HARQ-RTT-Timer expires:

2> If the corresponding HARQ process is not decoded successfully:

3> Start the sidelink reception drx-RetransmissionTimer for the corresponding HARQ process. In this case, the time point may be the first symbol after expiration of the reception drx-HARQ-RTT-Timer. or any point in time.

1> If sidelink transmit drx-HARQ-RTT-Timer expires:

2> Start the sidelink transmission drx-RetransmissionTimer for the corresponding HARQ process. In this case, the time point may be the first symbol after expiration of the transmission drx-HARQ-RTT-Timer. or any point in time.

If the sidelink DRX inactivity timer and the sidelink short cycle are configured, the following operation may be performed.

1> If the sidelink DRX inactivity timer expires:

2> If a sidelink short cycle is configured:

3> Start or restart the sidelink Short cycle timer (the duration the UE shall follow the Short DRX cycle). In this case, the time may be the first symbol after expiration of the corresponding sidelink DRX inactivity timer. or any point in time.

3> Use sidelink Short DRX cycle.

2> otherwise

3> Use sidelink Long DRX cycle.

1> If sidelink Short DRX cycle is used, [(SFN Х 10) + subframe number] modulo (sidelink drx-ShortCycle) = (sidelink drx-StartOffset) modulo (drx-ShortCycle):

2> Start sidelink DRX on-duration timer after sidelink DRX slot offset from the start of the subframe. (start sidelink drx-onDurationTimer after drx-SlotOffset from the beginning of the subframe.)

1> If sidelink Long DRX cycle is used, [(SFN Х 10) + subframe number] modulo (drx-LongCycle) = drx-StartOffset:

2> Start the sidelink DRX duration timer after the sidelink DRX slot offset from the start of the subframe.

The operation according to the basic sidelink DRX parameter configuration has been described above. Hereinafter, the link between resource selection and DRX operation will be described.

A method of linking resource selection of a transmitting terminal and a sidelink DRX operation of a counterpart receiving terminal

As described above, in the sidelink interface between the terminal and the terminal, unlike the Uu interface between the terminal and the base station, the terminal can perform communication by switching transmission/reception with another terminal through one sidelink carrier. Alternatively, the terminal may perform communication by switching transmission and reception with a specific counterpart terminal. Therefore, when applying the sidelink DRX function for sidelink reception to the terminal, it is necessary to consider the operation on the sidelink transmission function.

While the terminal performs the sidelink DRX function, the terminal (eg, terminal autonomous resource allocation terminal) may perform sensing for (re)selection of sidelink resources. The UE may (re)select some specific sidelink resources. And the terminal may reserve a plurality of sidelink resources. A resource selection mechanism may be configured for each transport pool. For example, one of random selection, partial sensing based selection (e.g. monitoring a subset of the full sensing window) and full sensing based selection may be configured. Random selection can (re)select resources without sensing. All resources within the resource selection window may be selected with the same probability. In partial sensing, sensing may be performed within one or a plurality of short time windows. The position of the sensing window, the position of the selecten window, the step size, etc. may be indicated through the RRC configuration.

While the counterpart terminal performs the DRX function for sidelink reception, the terminal paired with the terminal (eg, terminal autonomous resource allocation terminal) may perform sensing for (re)selection of sidelink resources. The paired terminal may (re)select some specific sidelink resources. And the paired terminal may reserve a plurality of sidelink resources. For each transport pool, a resource selection mechanism may be configured for each transport pool. For example, one of random selection, partial sensing-based selection, and full sensing-based selection may be configured. In order for the (transmitting) terminal's data transmission through the sidelink interface to be received by the counterpart (receiving) terminal operating the DRX function, the (transmitting) terminal needs to transmit data during the active time of the counterpart (receiving) terminal there is

As an example, while the sidelink DRX duration timer of the (receiving) terminal is operating, the (transmitting) terminal may limit (re)select a resource. For this, the corresponding sidelink DRX configuration may be associated with the resource pool. Each resource pool may be linked to at least one of random selection, partial sensing-based selection, and full sensing-based selection.

If the MAC entity of the (transmitting) terminal has selected to generate the selected sidelink grant corresponding to a plurality of MAC PDUs, and sidelink data is available in one logical channel, check the TX resource (re)selection on the selected resource pool can be performed.

If TX resource (re)selection is triggered as a result of the TX resource (re)selection check of the (transmitting) terminal, time and frequency resources may be randomly selected from the resources indicated by the physical layer. Alternatively, the (transmission) terminal may randomly select time and frequency resources for one transmission opportunity from the resources indicated by the physical layer. Alternatively, the (transmission) terminal may randomly select time and frequency resources for one or more transmission opportunities from available resources according to the selected time/frequency resource.

The corresponding time resource may be randomly selected from among the time resources included in the time when the sidelink DRX on-duration timer operates. For example, [(SFN Х 10) + subframe number] modulo (drx-LongCycle) = drx-StartOffset from the start of the subframe (slot) to the sidelink DRX slot offset after the sidelink DRX duration timer value is added within the time It can be selected from among the included time resources. Here, the subframe may be a slot. Alternatively, when the sidelink DRX duration timer expires, the selected sidelink grant/resource may be released/discarded/removed/cleared. TX resource (re)selection [or (re)selection check] may be performed on the selected resource pool.

As another example, while the sidelink DRX inactivity timer of the (receiving) terminal is operating, the (transmitting) terminal may limit (re)select the resource. For this, the corresponding sidelink DRX configuration may be associated with the resource pool. Each resource pool may be linked to at least one of random selection, partial sensing-based selection, and full sensing-based selection.

If the MAC entity of the (transmitting) terminal has selected to generate the selected sidelink grant corresponding to a plurality of MAC PDUs, and sidelink data is available in one logical channel, a TX resource (re)selection check is performed on the selected resource pool. can be done

If TX resource (re)selection is triggered as a result of the TX resource (re)selection check of the (transmitting) terminal, time and frequency resources may be randomly selected from the resources indicated by the physical layer. Alternatively, the (transmission) terminal may randomly select time and frequency resources for one transmission opportunity from the resources indicated by the physical layer. Alternatively, the (transmission) terminal may randomly select time and frequency resources for one or more transmission opportunities from available resources according to the selected time/frequency resource.

The corresponding time resource may be randomly selected from among the time resources included in the time the sidelink DRX inactivity timer operates. Alternatively, when the sidelink DRX inactivity timer expires, the selected sidelink grant/resource may be released/discarded/removed/cleared. TX resource (re)selection [or (re)selection check] may be performed on the selected resource pool.

As another example, while the sidelink transmission DRX retransmission timer or the sidelink reception DRX retransmission timer of the (receiving) UE is operating, the (transmitting) UE may limit (re)select resources. For this, the corresponding sidelink DRX configuration may be associated with the resource pool. Each resource pool may be linked to at least one of random selection, partial sensing-based selection, and full sensing-based selection.

If the MAC entity of the (transmitting) terminal has selected to generate the selected sidelink grant corresponding to a plurality of MAC PDUs, and sidelink data is available in one logical channel, check the TX resource (re)selection on the selected resource pool can be performed.

If TX resource (re)selection is triggered as a result of the TX resource (re)selection check of the (transmitting) terminal, time and frequency resources may be randomly selected from the resources indicated by the physical layer. Alternatively, the (transmission) terminal may randomly select time and frequency resources for one transmission opportunity from the resources indicated by the physical layer. Alternatively, the (transmission) terminal may randomly select time and frequency resources for one or more transmission opportunities from available resources according to the selected time/frequency resource.

The corresponding time resource may be randomly selected from among time resources included in the time when the sidelink transmission DRX retransmission timer or the sidelink reception DRX retransmission timer operates. Alternatively, when the sidelink transmission DRX retransmission timer or the sidelink reception DRX retransmission timer expires, the selected sidelink grant/resource may be released/discarded/removed/cleared. TX resource (re)selection [or (re)selection check] may be performed on the selected resource pool.

How to link sidelink DRX operation with sidelink resource reservation period

While the counterpart terminal performs the DRX function for sidelink reception, the terminal paired with the terminal (eg, terminal autonomous resource allocation terminal) may perform sensing for (re)selection of sidelink resources. The paired terminal may (re)select some specific sidelink resources. And the paired terminal may reserve a plurality of sidelink resources. For each transport pool, a resource selection mechanism may be configured for each transport pool. For example, at least one of random selection, partial sensing-based selection, and full sensing-based selection may be configured. In order for the data transmission of the (transmitting) terminal through the sidelink interface to be received by the other (receiving) terminal operating the DRX function, the resource reserved by the (transmitting) terminal is in the active time of the counterpart (receiving) terminal. Data needs to be transmitted to be included. Otherwise, the UE may consider that the reserved resource is not valid.

As an example, according to the period/cycle in which the sidelink DRX duration timer of the (receiving) terminal operates, the (transmitting) terminal may limit the reservation of resources. For this, the corresponding sidelink DRX configuration may be associated with the resource pool. Each resource pool may be linked to at least one of random selection, partial sensing-based selection, and full sensing-based selection.

If the MAC entity has selected to generate a selected sidelink grant corresponding to a plurality of MAC PDUs, and sidelink data is available in one logical channel, a TX resource (re)selection check may be performed on the selected resource pool.

If TX resource (re)selection is triggered as a result of the TX resource (re)selection check, an allowed value configured by RRC in the sidelink resource reservation period list may be selected. In addition, the resource reservation interval may be set to a selected value. The value for the resource reservation interval included in the resource reservation period list may be indicated in connection with the DRX cycle value. For example, it may be configured with the same value as the DRX cycle or an arbitrary multiple value.

Time and frequency resources may be randomly selected from resources indicated by the physical layer. Alternatively, time and frequency resources for one transmission opportunity may be randomly selected from the resources indicated by the physical layer. Alternatively, time and frequency resources for one or more transmission opportunities may be randomly selected from available resources according to the selected time/frequency resource.

A randomly selected resource may be used to select a set of periodic resources spaced by a resource reservation interval for transmission of PSCCH and PSSCH.

The corresponding resource may be randomly selected from among the resources included in the time when the aforementioned arbitrary sidelink DRX parameter (e.g. sidelink DRX duration timer) operates.

How to link the position of the sensing window, the position of the selecten window, and the step size to the DRX parameters

While the counterpart terminal performs the DRX function for sidelink reception, the terminal paired with the terminal (eg, terminal autonomous resource allocation terminal) may perform sensing for (re)selection of sidelink resources. The paired terminal may perform some sensing during the active time or during the active time from a predetermined offset before the active time and (re)select a specific sidelink resource. And the paired terminal may reserve a plurality of sidelink resources.

Full sensing or partial sensing may be configured such that sensing is performed within one or a plurality of short time windows. Partial sensing may be configured such that sensing is performed on a subset of the full sensing window. The position of the sensing window, the position of the selecten window, the step size, etc. may be indicated through the RRC configuration.

At least one parameter among the position of the sensing window, the position of the selecten window, and the step size may be configured in connection with any DRX parameter. For example, while the sidelink DRX duration timer of the (receiving) terminal is operating, the (transmitting) terminal may be configured to perform sensing. As another example, when the sidelink DRX duration timer of the (receiving) terminal starts (or before a predetermined offset of the start of the corresponding timer), the (transmitting) terminal may be configured to start sensing. As another example, when the sidelink DRX duration timer of the (receiving) terminal is stopped/expired (or before a predetermined offset of the corresponding timer), the (transmitting) terminal may be configured to stop/stop sensing. Although the description is based on the sidelink DRX duration timer for convenience of description, the use of arbitrary sidelink DRX parameters is also included in the scope of the present embodiment.

The embodiments described above may be applied to unicast-based sidelink communication supporting one PC5-RRC connection for a pair of a source L2 ID and a destination L2 ID in an access stratum (AS). The aforementioned arbitrary parameters may be indicated and applied from one terminal to the other terminal through the sidelink RRC reconfiguration message. The PC5-RRC connection is a logical connection between two terminals for a pair of source L2 IDs and destination L2 IDs, and may be established after PC5 unicast link establishment.

Also, the above-described operation may be applied to groupcast-based sidelink communication in which user traffic is transmitted and received through a sidelink among terminals belonging to one group. It can also be applied to broadcast-based sidelink communication in which user traffic is transmitted and received through the sidelink among the aforementioned terminals.

According to the present disclosure, sidelink communication can be performed power-efficiently.

Hereinafter, configurations of a terminal capable of performing some or all of the above-described embodiments and other paired terminals will be described once again with reference to the drawings.

11 is a diagram for explaining a terminal configuration according to an embodiment.

Referring to FIG. 11 , a terminal 1100 performing sidelink communication uses a receiver 1130 that receives a sidelink RRC (Radio Resource Control) message from a base station or another terminal and information included in the sidelink RRC message. and a control unit 1110 that configures sidelink discontinuous reception (DRX) parameters and monitors reception of sidelink data using the sidelink DRX parameters.

For example, the receiver 1130 may receive a sidelink RRC message from the base station. The sidelink RRC message may be a sidelink RRC reconfiguration message. The sidelink RRC message may include information for configuring sidelink or sidelink DRX in the terminal.

As another example, the receiver 1130 may receive a sidelink RRC message from another terminal. The sidelink RRC message may be a sidelink RRC reconfiguration message. The sidelink RRC message may include information for configuring sidelink or sidelink DRX in the terminal.

For example, the sidelink RRC message may include a sidelink DRX parameter. The sidelink DRX parameter may include one or more pieces of information necessary for the UE to perform a DRX operation in the process of performing sidelink communication.

As an example, the sidelink DRX parameter may include a sidelink DRX CSI timer for receiving sidelink channel status information (CSI). As another example, the sidelink DRX parameters include the aforementioned sidelink DRX duration timer, sidelink DRX slot offset, sidelink DRX cycle, sidelink DRX start offset, sidelink DRX inactivity timer, sidelink receive DRX HARQ RTT timer, side At least one of a link reception DRX retransmission timer and a sidelink transmission DRX retransmission timer may be further included. As another example, the sidelink DRX parameter may include a sidelink DRX resource reservation timer.

Meanwhile, the sidelink DRX CSI timer may be set to start in connection with transmission of sidelink control information including a request for sidelink channel state information to another terminal. That is, the controller 1110 may configure a sidelink DRX CSI timer by receiving the sidelink RRC message, and may associate the start of the sidelink DRX CSI timer with the operation of transmitting the sidelink CSI request.

In addition, the sidelink DRX CSI timer may be set to expire when at least one event of receiving sidelink channel state information from another terminal and reaching a delay time range set for a sidelink channel state information report is satisfied. For example, when the sidelink channel state information is received while the sidelink DRX CSI timer is running, the controller 1110 may terminate (expire) the sidelink DRX CSI timer. Alternatively, when the sidelink DRX CSI timer is in operation, the controller 1110 may terminate (expire) the sidelink DRX CSI timer when the delay time range set for the sidelink channel state information is reached.

The controller 1110 may configure sidelink DRX parameters and monitor sidelink data discontinuously in performing sidelink communication. Accordingly, a response to the sidelink channel state information according to the request for sidelink channel state information should be made when the terminal performs sidelink data monitoring. Accordingly, the controller 1110 performs an operation of monitoring the sidelink control information while the sidelink DRX CSI timer is running.

In addition to this, the controller 1110 controls the overall operation of the terminal 1100 according to the sidelink communication through the DRX operation required for performing the above-described embodiment.

The transmitter 1120 and the receiver 1130 are used to transmit/receive signals, messages, and data necessary for performing the above-described embodiment with a base station or another terminal.

12 is a diagram for explaining the configuration of another terminal according to an embodiment.

Referring to FIG. 12 , another terminal 1200 performing sidelink communication includes a transmitter 1220 that transmits a sidelink RRC (Radio Resource Control) message to the terminal and sidelink channel status information (CSI) from the terminal. ) includes a receiver 1230 that receives the request and a controller 1210 that controls transmission of sidelink channel state information while the sidelink DRX CSI timer is operating in the terminal.

The sidelink RRC message may be a sidelink RRC reconfiguration message. The sidelink RRC message may include information for configuring sidelink or sidelink DRX in the terminal.

The receiver 1230 may receive a request message for requesting sidelink CSI from the terminal. The request message may be included in the sidelink control information. When receiving the sidelink CSI request, the controller 1210 measures channel state information according to the request.

Meanwhile, the sidelink RRC message may include a sidelink DRX parameter. The sidelink DRX parameter may include one or more pieces of information necessary for the UE to perform a DRX operation in the process of performing sidelink communication.

For example, the sidelink DRX parameter may include a sidelink DRX CSI timer for the UE to receive sidelink channel status information (CSI). As another example, the sidelink DRX parameters include the aforementioned sidelink DRX duration timer, sidelink DRX slot offset, sidelink DRX cycle, sidelink DRX start offset, sidelink DRX inactivity timer, sidelink receive DRX HARQ RTT timer, side At least one of a link reception DRX retransmission timer and a sidelink transmission DRX retransmission timer may be further included. As another example, the sidelink DRX parameter may include a sidelink DRX resource reservation timer. As such, the sidelink RRC message may include various information necessary for the terminal to perform a sidelink DRX operation.

The sidelink DRX CSI timer may be set so that the terminal starts in connection with transmission of sidelink control information including a request for sidelink channel state information to another terminal. That is, the UE may configure a sidelink DRX CSI timer by receiving the sidelink RRC message, and may associate the start of the sidelink DRX CSI timer with the operation of transmitting the sidelink CSI request.

In addition, the sidelink DRX CSI timer may be set to expire when at least one event of receiving sidelink channel state information from another terminal and reaching a delay time range set for a sidelink channel state information report is satisfied. For example, when the sidelink channel state information is received while the sidelink DRX CSI timer is running, the UE may terminate (expire) the sidelink DRX CSI timer. Alternatively, the UE may terminate (expire) the sidelink DRX CSI timer when the delay time range set for the sidelink channel state information is reached when the sidelink DRX CSI timer is in operation.

Accordingly, the controller 1210 may measure the channel state according to the sidelink CSI request received from the terminal, and control the measurement result to be transmitted during a time period in which the sidelink DRX CSI timer configured in the terminal is operating. For example, the UE may configure sidelink DRX parameters and monitor sidelink data discontinuously in performing sidelink communication. Accordingly, a response to the sidelink channel state information according to the request for sidelink channel state information should be made when the terminal performs sidelink data monitoring.

In addition to this, the controller 1210 controls the overall operation of the other terminal 1200 according to the sidelink communication through the DRX operation required for performing the above-described embodiment.

The transmitter 1220 and the receiver 1230 are used to transmit/receive signals, messages, and data necessary for performing the above-described embodiment with the base station or the terminal.

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

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

In the case of implementation by hardware, the method according to the present embodiments may include one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), may be implemented by a processor, a controller, a microcontroller or a microprocessor.

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

Also, as described above, terms such as "system", "processor", "controller", "component", "module", "interface", "model", or "unit" generally refer to computer-related entities hardware, hardware and software. may mean a combination of, software, or running software. For example, the aforementioned component may be, but is not limited to, a process run by a processor, a processor, a controller, a controlling processor, an object, a thread of execution, 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 may reside within a process and/or thread of execution, and the components may be located on one device (eg, a system, computing device, etc.) or distributed across two or more devices.

The above description is merely illustrative of the technical spirit of the present disclosure, and various modifications and variations will be possible without departing from the essential characteristics of the present disclosure by those skilled in the art to which the present disclosure belongs. In addition, the present embodiments are not intended to limit the technical spirit of the present disclosure, but to explain, and thus the scope of the present technical spirit is not limited by these embodiments. The protection scope of the present disclosure should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present disclosure.

Claims (20)

A method for a terminal to perform sidelink communication, the method comprising:
Receiving a sidelink RRC (Radio Resource Control) message from a base station or another terminal;
configuring a sidelink discontinuous reception (DRX) parameter using information included in the sidelink RRC message; and
and monitoring reception of sidelink data using the sidelink DRX parameter. The method of claim 1,
The sidelink DRX parameter is
A method comprising a sidelink DRX CSI timer for receiving sidelink channel status information (CSI). 3. The method of claim 2,
The sidelink DRX CSI timer is
A method configured to be started in connection with transmission of sidelink control information including the request for sidelink channel state information to another terminal. 3. The method of claim 2,
The sidelink DRX CSI timer is
The method is configured to expire when at least one event of receiving the sidelink channel state information from another terminal and reaching a delay time range set for the sidelink channel state information report is satisfied. 3. The method of claim 2,
Monitoring the reception of the sidelink data comprises:
A method of monitoring sidelink control information while the sidelink DRX CSI timer is running. In a method for another terminal to perform sidelink communication,
Transmitting a sidelink RRC (Radio Resource Control) message to the terminal;
receiving a request for sidelink channel status information (CSI) from the terminal; and
and controlling, in the terminal, to transmit the sidelink channel state information while a sidelink DRX CSI timer is operating. 7. The method of claim 6,
The sidelink RRC message is
and a sidelink discontinuous reception (DRX) parameter, wherein the sidelink DRX parameter includes the sidelink DRX CSI timer for receiving sidelink channel state information. 8. The method of claim 7,
The sidelink DRX CSI timer is
A method configured to be started in connection with transmission of sidelink control information including a request for sidelink channel state information to the other terminal. 8. The method of claim 7,
The sidelink DRX CSI timer is
The method is configured to expire when at least one event of receiving the sidelink channel state information from the other terminal and reaching a delay time range set for the sidelink channel state information report is satisfied. 7. The method of claim 6,
The terminal is
A method of monitoring sidelink control information while the sidelink DRX CSI timer is running. In a terminal performing sidelink communication,
a receiver for receiving a sidelink RRC (Radio Resource Control) message from a base station or another terminal;
Configure a sidelink Discontinuous Reception (DRX) parameter using information included in the sidelink RRC message,
and a control unit monitoring reception of sidelink data using the sidelink DRX parameter. 12. The method of claim 11,
The sidelink DRX parameter is
A terminal including a sidelink DRX CSI timer for receiving sidelink channel status information (CSI). 13. The method of claim 12,
The sidelink DRX CSI timer is
A terminal configured to be started in connection with transmission of sidelink control information including the request for sidelink channel state information to another terminal. 13. The method of claim 12,
The sidelink DRX CSI timer is
A terminal configured to expire when at least one event of receiving the sidelink channel state information from another terminal and reaching a delay time range set for the sidelink channel state information report is satisfied. 13. The method of claim 12,
The control unit is
A terminal monitoring sidelink control information while the sidelink DRX CSI timer is operating. In another terminal performing sidelink communication,
a transmitter for transmitting a sidelink RRC (Radio Resource Control) message to the terminal;
a receiving unit for receiving a request for sidelink channel status information (CSI) from the terminal; and
and a control unit controlling the sidelink channel state information to be transmitted while the sidelink DRX CSI timer is operating in the terminal. 17. The method of claim 16,
The sidelink RRC message is
and a sidelink discontinuous reception (DRX) parameter, wherein the sidelink DRX parameter includes the sidelink DRX CSI timer for receiving sidelink channel state information. 18. The method of claim 17,
The sidelink DRX CSI timer is
Another terminal configured to be started in connection with transmission of sidelink control information including the request for sidelink channel state information to the other terminal. 18. The method of claim 17,
The sidelink DRX CSI timer is
Another terminal configured to expire when at least one event of receiving the sidelink channel state information from the other terminal and reaching a delay time range set for the sidelink channel state information report is satisfied. 17. The method of claim 16,
The terminal is
Another terminal that monitors sidelink control information while the sidelink DRX CSI timer is running.

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