CN116998200A - Method and device for supporting side-link discontinuous reception in wireless communication system - Google Patents

Abstract

The present disclosure provides a method and apparatus for transmitting side link data by a first User Equipment (UE) in a wireless communication system supporting side link communication between the first UE and a second UE. The method includes identifying configuration information including information associated with Discontinuous Reception (DRX) of side link communications, and transmitting side link data to a second UE within a DRX active time, where the second UE performs DRX operation, the DRX active time of the second UE being identified based on the configuration information.

Description

Method and apparatus for supporting side link discontinuous reception in a wireless communication system

Technical Field

The present disclosure relates generally to a wireless communication system, and more particularly, to a method and apparatus for performing Discontinuous Reception (DRX) in a wireless communication system supporting side link communication.

Background

In order to meet the increasing demand for wireless data traffic since the fourth generation (4G) communication systems entered the market, efforts have been made to develop enhanced fifth generation (5G) communication systems or former 5G communication systems. Therefore, the 5G communication system or the former 5G communication system is referred to as a super 4G network communication system or a Long Term Evolution (LTE) after-system.

For higher data transmission rates, 5G communication systems are considered to be implemented on the ultra-high frequency millimeter wave (mmWave) band of, for example, 60 gigahertz (GHz). In order to mitigate the path loss on the ultra-high frequency band and increase the arrival range of radio waves, the following technique is considered: 5G communication systems, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas.

Various technologies have also been developed to enable 5G communication systems with enhanced networks, such as evolved or advanced small cells, cloud radio access networks (cloud RANs), ultra dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, coordinated multipoint (CoMP), and received interference cancellation.

There are various other schemes that are being developed for 5G systems, including, for example, hybrid Frequency Shift Keying (FSK) and quadrature amplitude modulation QAM (FQAM) and Sliding Window Superposition Coding (SWSC) as Advanced Code Modulation (ACM) schemes, and Filter Bank Multicarrier (FBMC), non-orthogonal multiple access (NOMA) and Sparse Code Multiple Access (SCMA) as advanced access schemes.

The internet is evolving from human-centric connected networks where information is created and consumed by humans to internet of things (IoT) networks where information is communicated and processed between things or other distributed components. Another emerging technology is internet of everything (IoE), which is a combination of big data processing technology and IoT technology, for example, through a connection with a cloud server.

In order to implement IoT, technical elements such as detection technology, wired/wireless communication, and network infrastructure, service interface technology, and security technology are required. Research into inter-object connection technologies such as sensor networks, machine-to-machine (M2M), or Machine Type Communication (MTC) is recently underway.

In an IoT environment, intelligent Internet Technology (IT) services may be provided that collect and analyze data generated by things connected to each other to create human life. Through conversion or integration of existing Information Technology (IT) technology and various industries, ioT may have various applications such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances industries, or advanced medical services.

Accordingly, various attempts are being made to apply the 5G communication system to 1oT. For example, 5G communication technologies such as sensor networks, M2M, and MTC are implemented by technologies including beamforming, MIMO, and array antennas. The application of cloud RANs as the big data processing technology described above may be considered as an example of a convergence between 5G technology and IoT technology.

Multiple services can be provided to users in a 5G communication system, which requires a method of providing services within the same time interval according to characteristics and an apparatus using the same. Various services provided by 5G communication systems, such as services satisfying the requirements of low latency and high reliability, are being studied. In particular, in the case of vehicle communication, unicast communication, multicast (or multicast) communication, and broadcast communication between a User Equipment (UE) and another UE are supported in the NR V2X system. Unlike LTE V2X, which is intended to transmit and receive basic safety information necessary for a vehicle to travel on a road, NR V2X is intended to provide higher-level services such as planning, advanced driving, extended sensor, or remote driving. An example of side link communication supported by a 5G communication system is vehicle-to-everything (V2X) communication. Hereinafter, for convenience of description, the V2X UE is an example of a UE performing side link communication, but the present disclosure may also be applied to various types of side link communication and V2X communication.

Disclosure of Invention

[ technical problem ]

The present disclosure is made to solve at least the above problems and/or disadvantages and to provide at least the advantages described below.

Accordingly, an aspect of the present disclosure is to provide a method and apparatus for efficiently supporting DRX in a wireless communication system supporting side link communication.

Another aspect of the present disclosure is to provide a method and apparatus for efficiently performing a sensing operation when performing a DRX operation in a wireless communication system supporting side link communication.

Another aspect of the present disclosure is to provide a method and apparatus for selecting resources when performing a DRX operation in a wireless communication system supporting side link communication.

Another aspect of the present disclosure is to provide a method and apparatus for efficiently selecting resources when a vehicle terminal exchanges information with another vehicle terminal and a pedestrian portable terminal using a side link in a wireless communication system supporting side link communication.

Another aspect of the present disclosure is to provide a procedure for sensing and resource selection when DRX is performed between terminals in side link communication. The disclosed method may be applied and effectively used to minimize power consumption of a terminal and enable sensing and resource selection to be performed in the context of a UE operating in DRX.

Technical scheme

According to aspects of the present disclosure, a method of transmitting side link data by a first UE in a wireless communication system supporting side link communication between the first UE and a second UE includes: identifying configuration information including information associated with Discontinuous Reception (DRX) of the side link communication; and transmitting the sidelink data to the second UE within a DRX active time in case the second UE performs the DRX operation, the DRX active time of the second UE being identified based on the configuration information.

According to aspects of the present disclosure, a first UE for transmitting side link data in a wireless communication system supporting side link communication between the first UE and a second UE includes a transceiver and a processor configured to identify configuration information including information associated with DRX for side link communication, and in case the second UE performs a DRX operation, to transmit side link data to the second UE via the transceiver within a DRX active time, the DRX active time of the second UE being identified based on the configuration information.

According to aspects of the disclosure, a method for receiving side link data by a second UE in a wireless communication system supporting side link communication between the first UE and the second UE includes: identifying configuration information including information associated with DRX for side link communication; and receiving side link data from the first UE during a DRX active time in case the second UE performs the DRX operation, the DRX active time of the second UE being identified based on the configuration information.

According to aspects of the present disclosure, a second UE for receiving side link data in a wireless communication system supporting side link communication between the first UE and the second UE includes a transceiver and a processor configured to identify configuration information including information associated with Discontinuous Reception (DRX) of the side link communication, and in case the second UE performs a DRX operation, receive the side link data from the first UE within a DRX active time, the DRX active time of the second UE being identified based on the configuration information.

Drawings

The foregoing and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which: fig. 1 illustrates a wireless communication system supporting side link communication according to an embodiment;

fig. 2 shows an example of a V2X communication method using side link communication according to an embodiment;

FIG. 3 illustrates a resource pool defined as a set of resources in time and frequency for transmission and reception in side link communication, according to an embodiment;

fig. 4 illustrates a method of allocating transmission resources by a base station in side link communication according to an embodiment;

fig. 5 illustrates a method of directly allocating/selecting transmission resources of side link communication by sensing by a UE in side link communication according to an embodiment;

Fig. 6 illustrates an example of a mapping structure of physical channels mapped in one slot in side link communication according to an embodiment;

fig. 7 illustrates a sensing window and a resource selection window necessary for a UE to perform resource (re) selection and re-evaluation of resource allocation/selection in side-chain communication when the UE operates in full sensing, according to an embodiment;

FIG. 8 illustrates a method for performing partial sensing in side link communication according to an embodiment;

FIG. 9 illustrates a method for performing partial sensing in side link communication according to an embodiment;

FIG. 10 illustrates a method according to an embodiment, wherein re-evaluation or preemption is additionally performed when partial sensing or random selection is performed in side link communication;

fig. 11A illustrates an inactive time (or off-duration) and an active time (or on-duration) of DRX determined according to a parameter set for DRX when performing a DRX operation in side-link communication, according to an embodiment;

fig. 11B illustrates an inactive time (or off-duration) and an active time (or on-duration) of DRX determined according to a parameter set for DRX when performing a DRX operation in side-link communication, according to an embodiment.

Fig. 12 illustrates a sensing method of a UE according to an embodiment;

fig. 13 illustrates a sensing method of a UE according to an embodiment;

fig. 14 illustrates a sensing method of a UE according to an embodiment;

fig. 15 illustrates an operation of a UE for sensing and resource selection when DRX is performed in side link communication according to an embodiment;

fig. 16 illustrates an internal structure of a UE according to an embodiment; and

fig. 17 shows an internal structure of a base station according to an embodiment.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

For clarity and brevity, descriptions of techniques that are known in the art and that are not directly related to the present disclosure are omitted.

Some elements may be exaggerated or shown schematically. The dimensions of each element do not necessarily reflect the actual dimensions of the element. The same reference numbers may be used throughout the drawings to refer to the same elements.

The advantages and features of the present disclosure and methods for accomplishing the same may be understood by the following embodiments described in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed herein, and various changes may be made thereto. The embodiments disclosed herein are provided solely to inform those of ordinary skill in the art of aspects of the disclosure.

As used herein, the term "unit" refers to a software element or a hardware element, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). The units play a specific role but are not limited to software elements or hardware elements. The units may be configured in a storage medium that may be addressed or configured to reproduce one or more processors. Thus, a unit includes elements such as software elements, object-oriented software elements, class elements, task elements, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data architectures, tables, arrays, and variables. The functionality provided for in the elements or units may be combined with additional elements or may be divided into sub-elements or sub-units. The elements or units may be implemented to render one or more CPUs in the device or a secure multimedia card. According to an embodiment, the "..unit" may comprise one or more processors.

The description of the embodiments of the present disclosure focuses mainly on RANs, new Radios (NRs) and core networks, packet cores (5G systems, or 5G core networks, or NG cores, or next generation cores) specified by the third generation partnership project (3 GPP) as a mobile communication standardization organization. However, the subject matter of the present disclosure, or slight variations thereto, may also be applicable to other communication systems sharing a similar technical background without departing from the scope of the present disclosure, as will be readily appreciated by those of ordinary skill in the art.

In a 5G system, a network data collection and analysis function (NWDAF), which is a network function for analyzing and providing data collected from a 5G network, may be defined to support network automation. The NWDAF may collect/store/analyze information from the 5G network and provide the results to unspecified Network Functions (NF). The analysis results can be used independently in each NF.

For ease of description, some terms or names defined in the 3GPP standards for 5G and NR LTE, or similar systems, may be used. However, the present disclosure is not limited by these terms and names, and is equally applicable to systems conforming to other standards.

As used herein, for ease of description, terms are provided as examples for identifying access nodes, representing network entities, representing messages, representing inter-network entity interfaces, and representing various identification information. Accordingly, the present disclosure is not limited by these terms, and these terms may be replaced with other similar terms.

Herein, an interface (uplink and downlink) between a base station and a UE may be referred to as Uu interface, and an interface for side link communication between UEs may be referred to as PC5 interface. Meanwhile, the vehicles herein may include vehicles supporting vehicle-to-vehicle (V2V) communication, vehicles supporting vehicle-to-pedestrian (V2P) communication, vehicles supporting vehicle-to-network (V2N) communication, or vehicles supporting vehicle-to-infrastructure (V2I). The UE may include a roadside unit (RSU) equipped with UE features, an RSU equipped with base station features, or an RSU equipped with some base station features and some UE features. RSUs may be installed in various roadside facilities, such as traffic lights, tunnels, and intersections.

In this context, a base station may support V2X communication and general cellular communication, or a base station may support V2X communication only. In this case, the base station may be a 5G base station (gNB), a 4G base station (eNB), or an RSU. Thus, in this disclosure, a base station may be referred to as an RSU.

Hereinafter, V2X UEs are exemplified as examples of UEs performing side link communication in order to be described in embodiments of the present disclosure, but embodiments of the present disclosure may be applied to various types of side link communication and V2X communication to which the present disclosure is applicable.

In side link communication, the UE may select transmission resources for side link transmission by direct sensing. Here, sensing is an operation in which the UE monitors a side link channel, and may include monitoring/decoding a physical side link control channel (PSCCH) and measuring side link reference signal received power (SL-RSRP). In this case, various sensing and resource selection methods may be considered according to the state of the UE and the transmission environment. In particular, the following resource selection modes/methods may be used.

Full sensing

Partial sensing

Random selection

In the above method, the full sensing is a method of performing sensing in a portion defined as a sensing window except for a slot in which the UE performs side link transmission. In the case of full sensing, there is a disadvantage in that power consumption of the UE increases since continuous monitoring must be performed in a portion defined as a sensing window. This will be described below with reference to fig. 7. Thus, partial sensing and random selection may be considered in view of low power consumption of the UE. In the present disclosure, for convenience of description, partial sensing and random selection are named as power saving modes. In partial sensing, the time slots for performing sensing are limited as compared to full sensing. As a more detailed method, periodic based partial sensing and continuous partial sensing may be considered. This will be described below with reference to fig. 8 and 9. Further, the random selection is a method in which the UE randomly performs resource selection. Thus, the random selection does not require a sensing operation. Even when random selection is performed, there may be a UE that cannot perform sensing due to power consumption and a UE that can sense. Note that if a UE performing random selection is capable of sensing, it may perform sensing. Sensing in this case may be used to perform re-evaluation or preemption. When partial sensing or random selection is performed, a different sensing window needs to be set for re-evaluation and preemption compared to full sensing. This is described below with reference to fig. 10.

In particular, DRX between UEs may be considered in side link communication. When DRX is applied in side link communication, power consumption of the UE can be minimized, thereby improving battery efficiency. Specifically, power consumption of the UE may occur in the following procedure.

Decoding control information first SCI sent over PSCCH: since UE scheduling information is included in the first SCI, by decoding the first SCI, corresponding information can be used to perform sensing

Decoding control information second SCI transmitted through PSSCH: the second SCI includes other control information not included in the first SCI

Decoding data transmitted through PSSCH

In the side link communication, a transmitting UE transmits side link control information (SCI) for scheduling side link data to a receiving UE through a physical side link control channel (PSCCH), and transmits side link data through a physical side link shared channel (PSSCH). In addition, SCI can also be transmitted through PSSCH. The SCI may include at least one of resource allocation information for transmitting side link data, modulation and Coding Scheme (MCS) information applied to the side link data, group destination ID information, source ID information, unicast destination ID information, power control information for side link power control, timing Advance (TA) information, DMRS configuration information for side link transmission, packet repetition transmission related information, and feedback information (a/N information) for the side link data.

In a period set as an inactive time when DRX is applied in side link communication, the UE may not perform decoding on the control information and the data information described above. In contrast, in a period set as an active time when DRX is applied, the UE may perform decoding on the control information and the data information described above. Thus, failure of the UE to perform channel sensing for resource selection may occur in the DRX inactivity period in side link communication. In the present disclosure, a case where UE sensing and resource selection may be limited when DRX is performed in side link communication is described, and a method and UE operation for solving this case are proposed. Fig. 1 illustrates a wireless communication system supporting side link communication according to an embodiment.

Referring to fig. 1, part (a) shows an example where all V2X UEs UE-1 and UE-2 are located within the coverage of the base station (in coverage, IC). All V2X UEs may receive data and control information from a base station through a Downlink (DL) or transmit data and control information to a base station through an Uplink (UL). In this case, the data and control information may include data and control information for V2X communication. The data and control information may be used for normal cellular communications. The V2X UE may transmit/receive data and control information for V2X communication through a Side Link (SL).

Part (b) of fig. 1 shows an example in which UE-1 in the V2X UE is located within the coverage of the base station and UE-2 is located outside the coverage of the base station, or in other words, some examples of partial coverage (partial coverage, PC) in which V2X UE-2 is located outside the coverage of the base station. The V2X UE-1 located within the coverage of the base station may receive data and control information from the base station through a downlink or transmit data and control information to the base station through an uplink. The V2X UE-2 located outside the coverage of the base station cannot receive data and control information from the base station through the downlink, nor cannot transmit data and control information to the base station through the uplink. V2X UE-2 may transmit/receive data and control information for V2X communication with V2X UE-1 through a side link.

Part (c) of fig. 1 shows an example in which all V2X UEs are located out of coverage (out of coverage, OOC) of the base station. Thus, V2X UEs UE-1 and UE-2 cannot receive data and control information from the base station over the downlink, nor cannot transmit data and control information to the base station over the uplink. V2X UE UE-1 and UE-2 may send/receive data and control information for V2X communication via the side links.

Part (d) of fig. 1 shows an example of a case where V2X communication is performed between V2X UE-1 and UE-2 located in different cells. In particular, part (d) of fig. 1 shows an example in which V2X UE-1 and UE-2 are connected to different base stations in a Radio Resource Control (RRC) connected state or a camp-on (RRC disconnected state, i.e. RRC idle state). In this case, V2X UE UE UE-1 may be a V2X transmitting UE and V2X UE UE-2 may be a V2X receiving UE. Alternatively, V2X UE UE-1 may be a V2X receiving UE and V2X UE UE-2 may be a V2X transmitting UE. V2X UE-1 may receive a System Information Block (SIB) from the base station (or camping station) to which it is connected, and V2X UE-2 may receive a SIB from another base station (or camping station) to which it is connected. In this case, as the SIB, an existing SIB or a SIB separately defined for V2X may be used. The information about the SIB received by V2X UE UE-1 and the information about the SIB received by V2X UE-2 may be different from each other. Thus, in order to perform V2X communication between UE-1 and UE-2 located in different cells, information needs to be consistent or a method for SIB information transmitted from different cells may be required.

For convenience of description, fig. 1 shows a V2X system composed of V2X UEs UE-1 and UE-2, but communication may be performed between two or more V2X UEs.

Fig. 2 shows an example of a V2X communication method using side link communication according to an embodiment.

Referring to part (a) of fig. 2, UE-1 201 (e.g., a transmitting (Tx) UE) and UE-2 202 (e.g., a receiving (Rx) UE) may perform one-to-one communication, which may be referred to as unicast communication.

Referring to part (b) of fig. 2, the Tx UE and the Rx UE may perform one-to-many communication, which may be referred to as multicast or multicast. In part (b) of fig. 2, UE-1 211, UE-2 212, and UE-3 213 form one group (group a) performing multicast communication. UE-4 214, UE-5 215, UE-6 216, and UE-7 217 form another group (group B) that performs multicast communications. Each UE may perform multicast communication only within the group to which it belongs. Communication between different groups may be achieved by unicast, multicast or broadcast communication. Although it is shown that two groups (group a, group B) are formed in part (B) of fig. 2, the present disclosure is not limited thereto.

The V2X UE in fig. 2 may perform broadcast communication when all V2X UEs receive data and control information transmitted by the V2X transmitting UE through a side link. As an example, when it is assumed that UE-1 211 in part (b) of fig. 2 is a Tx UE for broadcasting, all UEs (UE-2 212, UE-3 213, UE-4 214, UE-5 215, UE-6 216, and UE-7 217) may receive data and control information transmitted by UE-1 211.

Unlike LTE V2X, NR V2X may consider a form that supports a vehicle UE to transmit data to only one specific node through unicast and a form that transmits data to a plurality of specific nodes through multicast. For example, these unicast and multicast techniques may be useful in service scenarios, such as formation, a technique that connects two or more vehicles via one network to allow these networks to travel in groups. In particular, unicast communication may be required for the purpose of controlling one specific node by the leader node of the formation group, whereas multicast communication may be required for the purpose of synchronously controlling a group consisting of a certain number of nodes.

Fig. 3 illustrates a resource pool defined as a set of resources in time and frequency for transmission and reception in side link communication, according to an embodiment.

The resource granularity of the time axis/domain in the resource pool may be time slots. The resource granularity of the frequency axis/domain may be a subchannel composed of one or more Physical Resource Blocks (PRBs). In the present disclosure, an example of discontinuously allocating resource pools in the time domain is described, but the resource pools may also be allocated continuously in the time domain. Although examples of continuously allocating resource pools in the frequency domain are described herein, methods of discontinuously allocating resource pools in the frequency domain are not precluded.

Referring to fig. 3, a case 301 in which resource pools are discontinuously allocated in the time domain is shown in a hatched area. Fig. 3 shows the case when the granularity of the resources in the time domain is a slot. A side link slot may be defined within a slot for the uplink. In particular, the length (e.g., number) of symbols used as side links in one slot may be set as side link bandwidth part (BWP) information. Therefore, in the time slot for uplink, symbols configured as side links are not guaranteedThe number of slots cannot be side link slots. As the slots belonging to the resource pool, the slots of the transmission side link synchronization signal block (S-SSB) are excluded. Referring to 301, a set of time slots in the time domain that may be used as side links, in addition to such time slots, is shown asThe shaded part in 301 indicates the side link slots belonging to the resource, which can be (in advance) configured by bitmap with the resource pool information.

Referring to 302, a set of sidelink timeslots belonging to a resource pool in the time domain is shown asIn the present disclosure, the (pre) configuration indicates configuration information previously configured and stored in the UE, or indicates a case where the UE is configured in a cell-common manner by the base station. The UE in the cell common indication cell receives configuration information on the same information from the base station. In this case, a method of obtaining cell common information by receiving a side link system information block (SL-SIB) from a base station may be considered. Cell common also indicates the case where the UE is configured in a UE-specific manner after establishing an RRC connection with the base station. Instead of being UE specific, it is possible to express UE specific, which means that configuration information is received as a specific value for each UE. In this case, a method of obtaining UE-specific information by receiving an RRC message from a base station may be considered. For the (pre) configuration, a method configured as resource pool information and a method not configured in the resource pool information may be considered. When (pre) configured as resource pool information, all UEs operating in the respective resource pools may be operated with common configuration information except in the case where the UEs are configured in a UE-specific manner after establishing an RRC connection with the base station. However, the method of not configuring the (pre) configuration in the resource pool information is basically a method of configuring the pre-configuration independently of the resource pool configuration information. For example, one or more modes (e.g., A, B and C) are (pre) configured in the resource pool, and a reference is made by the (pre) configured information as to what mode is to be used among the (pre) configured modes in the resource pool information, independently of the resource pool configuration information Shown.

Referring to 303 of fig. 3, a case of continuously allocating resource pools in the frequency domain is shown. On the frequency axis, resource allocation may be set using SL BWP information and may be performed in units of subchannels. A subchannel may be defined as a granularity of resources on a frequency consisting of one or more PRBs. For example, a subchannel may be defined as an integer multiple of a PRB. Referring to 303, the subchannel may be composed of 5 consecutive PRBs, and the subchannel size (sizebchannel) may be the size of 5 consecutive PRBs. However, the contents shown in the drawings are only examples, and the size of the sub-channels may be differently set. Although typically one sub-channel consists of consecutive PRBs, it does not have to consist of consecutive PRBs. The sub-channel may be a basic unit of resource allocation of the PSSCH. In 303, startRB-Subchannel may indicate the starting position of the Subchannel on frequency in the resource pool. When resource allocation is performed in units of subchannels on the frequency axis, resources on the frequency can be allocated by configuration information such as a Resource Block (RB) index (startRB-Subchannel) at which a Subchannel starts, information (sizebchannel) on how many PRBs the Subchannel is composed, and the total number of subchannels (numsubbhannel). In this case, information about startRB-Subchannel, sizeSubchannel and numsubbhannel may be (pre) configured as frequency resource pool information.

Fig. 4 illustrates a method of allocating transmission resources by a base station in side link communication according to an embodiment.

Hereinafter, a method of allocating transmission resources by a base station in side link communication will be referred to as mode 1, which is a scheduled resource allocation. Mode 1 may indicate a method in which a base station allocates resources for side chain transmission to RRC-connected UEs in a dedicated scheduling scheme. Since the base station can manage side-chain communication resources, the mode 1 approach can be efficient for interference management and resource pool management.

Referring to fig. 4, a tx UE 401 may camp on a base station (gNB) 403 (405). The UE camping on the indication in the standby state (rrc_idle) may select (or reselect) a base station (cell) as needed and receive system information or paging information, etc.

The receiving UE 402 may camp on the base station (cell) 403 when the Rx UE 402 is located within the coverage of the base station (cell) 403 (407). Conversely, when the receiving UE 402 is located outside the coverage of the base station (cell) 403, the receiving UE 402 may not camp on the base station (cell) 403.

In this disclosure, rx UE 402 represents a UE that receives data transmitted by transmitting UE 401.

Each of the Tx UE 401 and the Rx UE 402 may receive SL-SIBs from the base station 403 (410). The SL-SIB information may include side link resource pool information for transmission/reception in side link communication, parameter configuration information for a sensing operation of resource selection, information for side link synchronization, or carrier information for side link transmission/reception operating at different frequencies. The Tx UE 401 and the Rx UE 402 may perform RRC configuration for side link communication through a PC5 RRC interface (415).

When data traffic for V2X communication is generated in Tx UE 401, tx UE 401 may be RRC connected to base station 403 (420), referred to herein as a Uu-RRC connection. Uu-RRC connection procedure 420 may be performed prior to data traffic generation for Tx UE 401. In mode 1, when Uu-RRC connection procedure 420 is performed between base station 403 and Rx UE 402, tx UE 401 may perform transmission to Rx UE 402 through a side link. In contrast, in mode 1, the Tx UE 401 may perform transmission to the Rx UE 402 through a side link even when the Uu-RRC connection procedure 420 is not performed between the base station 403 and the Rx UE 402.

The Tx UE 401 may transmit a request for transmission resources capable of performing V2X communication with the Rx UE 402 to the base station (430) using an uplink Physical Uplink Control Channel (PUCCH), an RRC message, or a Medium Access Control (MAC) Control Element (CE). The MAC CE may be a new format Buffer Status Report (BSR) MAC CE (including information about the size of data buffered for device-to-device (D2D) communication and it is an indicator of BSR for at least V2X communication). Tx UE 401 may request side chain resources through a Scheduling Request (SR) bit transmitted through an uplink physical control channel (PUCCH). In mode 1, the UE may additionally transmit information to the base station that may assist the base station in scheduling. This may be performed by an RRC message or MAC CE. In the present disclosure, the method for indicating the corresponding information is not limited thereto. The corresponding information may be referred to as ueassistance information.

Base station 403 may allocate V2X transmission resources to Tx UE 401. In this case, the base station may allocate transmission resources in a dynamic grant or a configured grant scheme.

In the dynamic grant scheme, a base station may allocate resources for TB transmission through Downlink Control Information (DCI). As the side link scheduling information included in the DCI, parameters related to transmission time of initial transmission and retransmission and a frequency allocation location information field may be included. The DCI for the dynamic grant scheme may be scrambled to a side link vehicle radio network temporary identifier (SL-V-RNTI) by a Cyclic Redundancy Check (CRC) to indicate the dynamic grant scheme.

In the configured grant scheme, the base station may periodically allocate resources for TB transmission by setting a semi-persistent scheduling (SPS) interval through Uu-RRC. In this case, the base station may allocate resources for one TB through DCI. The side link scheduling information of one TB included in the DCI may include parameters related to transmission time of initial transmission and retransmission resources and frequency allocation location information. When resources are allocated in the configured grant scheme, the transmission time/occasion of the initial transmission and retransmission of one TB and the frequency allocation position may be determined by DCI, and the resources for the next TB may be repeated at SPS intervals.

The DCI for the configured grant scheme may be CRC scrambled to the SL-SPS-V-RNTI to indicate the configured grant scheme. The activation/retransmission/reactivation/release of SPS transmissions in sidelink communication may be indicated to the UE through the PDCCH and the SL-SPS-V-RNTI is an identifier for identifying the UE. Configured Grant (CG) schemes may be divided into type 1CG and type 2CG. In the case of type 2CG, a set of resources that are authorized for configuration by DCI may be activated/deactivated.

Thus, in mode 1, the base station 403 may instruct the Tx UE 401 to schedule side link communication with the Rx UE 402 by DCI transmission via PDCCH (440).

Specifically, the DCI format 3_0 or the DCI format 3_1 may be DCI for side-link communication to the Tx UE 401 by the base station 403. The DCI format 3_0 may be DCI for scheduling an NR side link in one cell, and the DCI format 3_1 may be DCI for scheduling an LTE side link in one cell.

In the case of broadcast transmission, the Tx UE 401 may perform transmission without the RRC configuration 415 of the side link. In contrast, in case of unicast or multicast transmission, the Tx UE 401 may perform RRC connection with another UE one-to-one. Unlike Uu-RRC, the RRC connection between UEs may be referred to as PC5-RRC 415. In the case of multicast, the PC5-RRC 415 may be independently connected between UEs in the group. Although the connection of the PC5-RRC 415 is shown in FIG. 4 after the transmission 410 of the SL-SIB, the connection may be performed at any time prior to the transmission 410 of the SCI or SL-SIB.

Tx UE 401 may send SCI (first stage) to Rx UE 402 over PSCCH (460). Tx UE 401 may send SCI (second level) to Rx UE 402 via PSSCH (470). In this case, information related to resource allocation may be included in the first stage SCI, and other control information may be included in the second stage SCI. Tx UE 401 may send data to Rx UE 402 through the PSSCH (480). In this case, the first Stage (SCI), the second Stage (SCI), and the PSSCH may be transmitted together in the same slot. For the first Stage (SCI) transmitted in the PSCCH and the second Stage (SCI) transmitted in the PSCCH, reference may be made to the NR standard TS 38.212.

Fig. 5 illustrates a method of directly allocating/selecting transmission resources of side link communication by sensing of a UE in side link communication according to an embodiment.

Hereinafter, a method in which the UE directly allocates/selects transmission resources for side link communication through sensing in the side link communication is referred to as mode 2. The method of mode 2 may be referred to as a method of UE autonomous resource selection. In mode 2, as system information, the base station 503 may provide a transmission/reception resource pool for V2X side link communication, and the Tx UE 501 may allocate/select transmission resources according to the set rule/standard. Unlike mode 1, in which the base station directly participates in resource allocation, in mode 2, the Tx UE 501 may autonomously/directly select resources for side link communication based on a resource pool previously received through system information and transmit data.

Referring to fig. 5, a tx UE 501 may camp on a base station (cell) 503 (505). The UE camping on the indication in the standby state (rrc_idle) may select (or reselect) a base station (cell) as needed and receive system information or paging information, etc. Referring to fig. 5, unlike fig. 4 described above, in mode 2, when a Tx UE 501 is located within the coverage of a base station (cell) 503, the Tx UE 501 may camp on the base station (cell) 503. Conversely, when the Tx UE 501 is located outside the coverage of the base station (cell) 503, the Tx UE 50 may not camp on the base station (cell) 503.

The Rx UE 502 may camp on the base station (cell) 503 when the Rx UE 502 is located within the coverage of the base station (cell) 503 (507). Conversely, when the Rx UE 502 is located outside the coverage of the base station (cell) 503, the Rx UE 502 may not camp on the base station (cell) 503.

The Tx UE 501 and the Rx UE 502 may receive SL-SIBs from the base station 503 (510). The SL-SIB information may include side link resource pool information for transmission/reception in side link communication, parameter configuration information for a sensing operation, information for side link synchronization, or carrier information for side link transmission/reception operating at different frequencies. The Tx UE 501 and the Rx UE 502 may perform RRC configuration for side-link communication through the PC5 interface (515).

The difference between the embodiment of fig. 4 and the embodiment of fig. 5 is that in the embodiment of fig. 4, the base station 403 and the UE 401 operate in an RRC connected state, whereas in the embodiment of fig. 5, the UE 501 may even operate in an idle mode 520 (in an RRC disconnected state). Even in the RRC connected state 520, the base station 503 may enable the Tx UE 501 to autonomously/directly allocate/select transmission resources without directly participating in resource allocation. The RRC connection between the UE 501 and the base station 503 may be referred to as Uu-RRC 520. When data traffic for V2X communication is generated in the Tx UE 501, the Tx UE 501 may be configured with a resource pool through system information received from the base station 503, and the Tx UE 501 may directly allocate/select time/frequency domain resources by sensing in the configured resource pool (530). When resources are finally allocated/selected, the allocated/selected resources are determined as grants for the side link transmission.

In the case of broadcast transmission, the Tx UE 501 may perform transmission without the RRC configuration 515 for side link communication. In contrast, in case of unicast or multicast transmission, the Tx UE 501 may perform RRC connection with another UE one-to-one. Unlike Uu-RRC, the RRC connection between UEs may be referred to as PC5-RRC 515. In the case of multicast, the PC5-RRC 515 may be independently connected between UEs in the group. Referring to fig. 5, although the connection of the PC5-RRC 515 is shown after the transmission 510 of the SL-SIB, the connection may be performed before the transmission 510 of the SL-SIB or at any time before the transmission of the SCI.

The Tx UE 501 may send SCI (first stage) to the Rx UE 502 over the PSCCH (550). Tx UE 401 may send SCI (second level) to Rx UE 402 via PSSCH (560). In this case, information related to resource allocation may be included in the first stage SCI, and other control information may be included in the second stage SCI. The Tx UE 501 may transmit data to the Rx UE 502 through the PSSCH (570). In this case, the first Stage (SCI), the second Stage (SCI), and the PSSCH may be transmitted together in the same slot. For the first Stage (SCI) transmitted in the PSCCH and the second Stage (SCI) transmitted in the PSCCH, reference may be made to the NR standard TS 38.212.

As SCI for side link communication for Tx UE 401 or 501 to communicate with Rx UE 402 or 502, SCI format 1-a may exist as SCI (first level). As SCI (second level), SCI format 2-a or SCI format 2-B may also be present. In SCI (second stage), SCI format 2-a may include information for PSSCH decoding and may be used when hybrid automatic repeat request (HARQ) feedback is not used or when HARQ feedback is used and all ACK or NACK information is included. In contrast, SCI format 2-B may include information for PSSCH decoding and be used when HARQ feedback is not used or when HARQ feedback is used and only NACK information is included. For example, SCI format 2-B may be used only for multicast transmissions.

Fig. 6 illustrates an example of a mapping structure of physical channels mapped in one slot in side link communication according to an embodiment.

Specifically, fig. 6 shows the mapping of PSCCH, PSSCH and physical side link feedback channel (PSFCH). In the case of PSFCH, when HARQ feedback of the side link is activated in a higher layer, the time resources of the PSFCH may be (pre) configured as resource pool information. The physical side link feedback channel (PSFCH) is a channel carrying side link feedback control information (SFCI). For example, in side link communication, the Rx UE may transmit an ACK or NACK as a signal to the Tx UE in response to the side link data that the Rx UE has received. The SFCI may include such ACK/NACK information.

The resources in the time domain for transmitting information in the PSFCH may be (pre) configured to a value of every 0, 1, 2 and 4 slots. 0 indicates that no PSFCH resource is used. 1. 2 and 4 represent the configuration of PSFCH resources every 1, 2 and 4 slots. Part (a) in fig. 6 shows a structure of a slot in which a PSFCH resource is not configured, and part (b) in fig. 6 shows an example of a structure of a slot in which a PSFCH resource is configured.

The PSCCH/PSSCH/PSFCH may be allocated to one or more subchannels in the frequency domain. The subchannel allocation has been described in detail above in connection with fig. 3. Referring to fig. 6, the mapping of PSCCH/PSSCH/PSFCH in the time domain is described. One or more symbols may be used as an Automatic Gain Control (AGC) region 602 before the Tx UE transmits PSCCH/PSSCH/PSFCH in a corresponding slot 601. Since an Rx UE transmitting information in the PSFCH may be adjacent to or remote from a Tx UE receiving information in the PSFCH, information passing through the PSFCH may be received by the Tx UE with high or low reception power. Thus, the Tx UE may set the AGC range to receive the information in the PSFCH with proper power. When the corresponding symbol is used for AGC, a method for repeating a signal of another channel in the corresponding symbol region and transmitting the signal may be considered. In this case, the repetition signal of another channel may be a PSCCH symbol or some pscsch symbols. In contrast, the preamble may be transmitted in the AGC region, which may advantageously further shorten the AGC execution time as compared to a method of repeatedly transmitting a signal of another channel. When the preamble signal is transmitted for AGC, a specific sequence may be used as the preamble signal 602. In this case, as the preamble, sequences PSSCH DMRS, PSCCH DMRS or channel state information reference signals (CSI-RS) may be used. Here, the sequence used as the preamble is not limited to the above example. In addition, according to fig. 6, control information related to resource allocation may be transmitted in early symbols of a slot as a first stage SCI in a PSCCH 603, and other control information may be transmitted as a second stage SCI in an area 604 of the PSSCH.

The data scheduled by the control information may be transmitted in the PSSCH 605. In this case, the time-domain position of the second stage SCI may be transmitted according to the symbol map of the first PSSCH DMRS. The time-domain position of the transmission PSSCH DMRS 606 may be different in the time slots in which the PSFCH is transmitted and in the time slots in which the PSFCH is not transmitted, as shown in parts (a) and (b) of fig. 6. The example of part (a) of fig. 6 shows that the PSFCH 607 is located at the end of a slot, and the PSFCH 607 is a physical channel for transmitting feedback control information. By ensuring a predetermined idle time (guard) between the PSSCH 605 and the PSFCH 607, a UE that has transmitted/received the PSSCH 605 can be allowed to prepare to transmit or receive the PSFCH 607. After sending and receiving the PSFCH 607, a predetermined idle period (guard) may be guaranteed.

Fig. 7 illustrates a sensing window and a resource selection window necessary for a UE to perform resource (re) selection and re-evaluation of resource allocation/selection in side-chain communication when the UE operates in full sensing, according to an embodiment.

Referring to fig. 7, when triggering resource (re) selection at time n, a sensing window 701 may be defined as a time period [ n-T ₀ ,n-T _proc,0 ]。T ₀ May be the start time of the sensing window and may be (pre) configured with the resource pool information. T (T) ₀ May be defined as a positive integer in milliseconds (ms) and is not limited to a particular value. T (T) _proc,0 May be defined as the time required to process the sensing result and is not limited to a specific value. For example T _proc,0 May be defined as a positive integer in ms or as a slot unit.

When triggering resource (re) selection at time n, the resource selection window 702 may be determined as [ n+T ] ₁ ,n+T ₂ ]。T ₁ Is a time slot unit value and can be specific to T ₁ ≤T _proc,1 The selection is effected in accordance with the UE. T (T) _proc,1 May be defined as the maximum reference value taking into account the processing time required to select the resource. For example T _proc,1 May be defined as different slot unit values according to subcarrier spacing (SCS), and is not limited to a specific value. T (T) ₂ Is a time slot unit value and can be satisfied by the UE when T is satisfied _2min ≤T ₂ And selecting within a range of less than or equal to the remaining Packet Delay Budget (PDB). T (T) _2min For preventing the UE from selecting too low a value as T2, and may be based on the priority (prio of Tx UE _TX ) And SCS is set to "T" by higher layers _2min (prio _TX ) ". The UE may select transmission resources in a resource selection window 702.

Fig. 7 shows an example of triggering resource (re) selection at time n, and even after time n, the UE continuously performs sensing, thereby performing triggering for re-evaluation and preemption at n '(n' > n). In particular, when the UE determines that the resources selected due to triggering the resource (re) selection at time n are not suitable for transmission by continuously performing sensing after selecting the transmission resources, re-evaluation may be triggered at time n '(n' > n). The continuous sensing of the UE may be performed in a manner that a plurality of sensing windows are configured in parallel or sequentially. When the resources reserved by the UE overlap with resources reserved by another UE and resources reserved by another UE have a higher priority, preemption (reselection) for resource change may be triggered at time n '(n' > n) and the interference to the corresponding resources is measured to be higher. In this case, the resource 703 selected and reserved by the resource (re) selection at time n may be changed to another resource (706). Fig. 7 shows both the sensing window 704 and the resource selection window 705 for a time n '(n' > n) of trigger re-evaluation and preemption.

Fig. 8 illustrates a method of performing partial sensing in side link communication according to an embodiment. Fig. 9 illustrates a method of performing partial sensing in side link communication according to an embodiment.

Unlike the full sensing in fig. 7, the embodiments of fig. 8 and 9 are different methods for determining a slot for performing sensing when the UE operates in the partial sensing. However, it should be noted that the present disclosure is not limited thereto. Note that in fig. 8 and 9, when partial sensing is performed, resource selection windows 801 and 901 may be determined as described above in connection with reference numeral 702 of fig. 7.

Fig. 8 is a method of determining a time slot in which a UE performs sensing based on a periodic reservation interval, and may also be referred to as periodic based partial sensing, or may be referred to as other terminology.

Referring to FIG. 8, in a resource selection window 801, Y (. Gtoreq.1) candidate slots for resource selection may be selected. In this case, Y candidate slots may be selected in time, either continuously or non-continuously, in the resource selection window. The minimum value of Y may be (pre) configured. The final choice of Y value and which slot is to be selected may be determined by the UE implementation. In this case, one of the Y candidate slots is indicated by 802 As described with reference to fig. 3 +.>Side link slots belonging to a resource pool may be indicated. In this case, the time slot in which the UE performs sensing through the period-based partial sensing may be determined asVector Y represents Y candidate slots and if there is only one slot, it may be represented as Y, as shown in fig. 8. Vector P _reserve Is a value corresponding to the periodic reservation interval and may include one or more values. If the value is one, it can be represented as P as shown in FIG. 8 _reserve . The inclusion in P may be determined from a (pre) configured periodic reservation interval list s 1-resourereserved period list _reserve And the following method can be considered. However, it should be noted that the present disclosure is not limited to the following methods 1-1 to 1-3.

Method 1-1: using all values included in the sl-ResourceReserve PeriodList

Method 1-2: using only some (subset) of the values included in the sl-resoureaverveperiodic list

Method 1-3: using common divisors of values included in sl-ResourceReserve PeriodList

At the position ofIn (c), vector k is a value that determines the number of time slots in which partial sensing is performed. The interval between the sense slots may be defined by the inclusion of P _reserve Is determined by the reservation interval of the (c). Fig. 8 shows an example in which k is 1, 2, 3, 4, and 5. For determining k, at least one of the following methods 2-1 to 2-6 may be considered. However, it should be noted that the present disclosure is not limited to the following method.

Method 2-1: the processing time of the resource selection may be considered to select only one nearest time slot before the Y candidate time slots or before the time 803 of triggering the resource (re) selection. For example, according to fig. 8, only the slot corresponding to 804 may be selected as the slot in which partial sensing is performed for the candidate slot 802 for resource selection. Only the slot corresponding to 814 may be selected as the slot for which partial sensing is performed for the candidate slot 812 for resource selection.

Method 2-2: the processing time of the resource selection may be considered to select only the two most recent time slots before the Y candidate time slots or before the time 803 of triggering the resource (re) selection. For example, according to fig. 8, only the slots corresponding to 804 and 805 may be selected as slots for which partial sensing is performed for the candidate slot 802. Only the slots corresponding to 814 and 815 may be selected as slots for which partial sensing is performed for candidate slot 812.

Method 2-3: the set sensing window [ n-T ] can be set ₀ ,n-T _proc,0 ]All time slots in (1) are determined asFor example, according to FIG. 8, when the window [ n-T ] is sensed ₀ ,n-T _proc,0 ]When set to 809, the time slots corresponding to reference numerals 804, 805, and 806 may be selected for use with the candidate pairTime slot 802 performs the sensed time slot. The slots corresponding to reference numerals 814, 815 and 816 may be selected as slots for performing sensing on the candidate slot 812.

Method 2-4: at P _reserve In this case, k may be determined in such a manner that only one slot is selected for one reservation interval, and k may be determined by the UE implementation. The maximum value of k may be (pre) configured. For example, according to fig. 8, the ue determines k=2 for the candidate slot 802, and may select only the slot corresponding to 805 as the slot for performing partial sensing. The UE determines k=2 for the candidate slot 812 and selects only the slot corresponding to 815 as the slot for performing partial sensing.

Method 2-5: one or more values of k may be (pre) configured by the method of (pre) configuring k. For example, according to fig. 8, when k=1 and 2 are (pre) configured for the candidate slots 802, only slots corresponding to reference numerals 804 and 805 may be selected as slots for performing partial sensing. When k=1 and 2 are (pre) configured for the candidate slots 812, only the slots corresponding to 814 and 815 may be selected as slots for performing partial sensing. A method of (pre) configuring different values of k according to a Channel Busy Ratio (CBR), which is a measurement indicating a channel congestion state, may be considered. In general, as channel congestion increases, the measured CBR value increases, while collision of selected resources needs to be prevented by performing better sensing when the channel is more congested. Therefore, when the CBR value is higher, a larger k value needs to be used. The threshold for selecting the CBR value of k may be determined by the UE implementation or (pre) configuration. In this case, the threshold value of the CBR value may also be determined to be a different value according to the priority.

Method 2-6: k is configured and determined using a bitmap (pre). For example, according to fig. 8, when a bitmap of length 5 is used for the candidate slot 802 and is (pre) configured to [10110], only slots corresponding to reference numerals 805, 806, and 808 may be selected as slots for performing partial sensing. When a bitmap of length 5 is used for the candidate slot 812 and is (pre) configured as [10110], only slots corresponding to reference numerals 815, 816, and 818 may be selected as slots for performing partial sensing.

Fig. 9 illustrates another method for performing part. Unlike the cycle-based partial sensing of fig. 8, the method shown in fig. 9 is for performing sensing based on a continuous sensing window, and may be referred to as continuous partial sensing, or may be referred to as other terms. Since partial sensing is performed in fig. 9, a sensing window shorter than that in the full sensing of fig. 7 may be used. Thus, the sensing window 903 for continuous partial sensing may be defined as [ n+T ] _A ,n+T _B ]Is a time period of (a). In this case, note that for triggering resource (re) selection, T _A And T _B The relative time n 902 may be set to a positive number as shown in part (a) of fig. 9, or may be set to a negative number as shown in part (b) of fig. 9. T (T) _A And T _B May be set to 0.

Fig. 10 illustrates a method according to an embodiment, wherein re-evaluation or preemption is additionally performed when partial sensing or random selection is performed in side link communication.

In contrast to the full sensing in fig. 7, when partial sensing or random selection is performed, a different sensing window needs to be set for re-evaluation and preemption. According to fig. 10, when a trigger for re-evaluation or preemption occurs in a time slot n ', a sensing window 1001 for re-evaluation and preemption may be set to a time period [ n' -T ] _C ,n'-T _proc,0 ]. Here, T _proc,0 Not limited to a particular value, but may be set to T as defined in the full sense described in connection with FIG. 7 _proc,0 The same value. T (T) _C Not limited to a particular value. For example, a value of 32 slots may be used as T _C . The resource selection window 1002 may be defined as a time period [ n' +T ] ₁ ,n'+T ₂ ]. For T ₁ And T ₂ Please refer to the description in connection with fig. 7. Thus, when a resource selection pattern is determined by partial sensing or random selection in the side link and re-evaluation or preemption is additionally performed, the resource 1003 that has been selected or reserved for re-evaluation and preemption can be re-selected as another resource 1004 in the resource selection window 1002 by the sensing result in the sensing window 1001. Note that in the following In case of machine selection, only UEs capable of performing sensing may perform re-evaluation and preemption.

Fig. 11A illustrates an inactive time (or off-duration) and an active time (or on-duration) of DRX determined according to a parameter set for DRX when performing a DRX operation in side-link communication, according to an embodiment. Fig. 11B illustrates an inactive time (or off-duration) and an active time (or on-duration) of DRX determined according to a parameter set for DRX when performing a DRX operation in side-link communication, according to an embodiment.

The UE may perform monitoring/decoding of the side channel for control information and data information for data reception in a period corresponding to an active time of the DRX. In contrast, in a period corresponding to the inactive time of DRX, monitoring/decoding for control information and data information for data reception may not be performed. In the side link communication, the control information includes a first SCI, which is control information transmitted through the PSCCH, and a second SCI, which is control information transmitted through the PSSCH. The data information may be transmitted through the PSSCH. It can be assumed that control information and data information are always simultaneously transmitted in side link communication. Therefore, the time point (slot) when the control information is received may be the same as the time point (slot) when the data information is received.

The inactivity time and activity time for DRX operation in side-link communication may be determined in consideration of the following parameters. However, it should be noted that in the present disclosure, parameters for determining the inactivity time and activity time of DRX are not limited to the parameters presented below. It is also noted that some of the following parameters may not be used in DRX for side link communication.

DRX related parameters

drx-cycle:

Indicating a period of time for which DRX is applied. The start position (drx-StartOffset) of drx-cycle1101 may be set. As shown in parts (a) and (b) of fig. 11, intervals of the inactive time 1110 and the active time 1111 may be set within the drx-cycle. In the side link communication, a drx-cycle having a long period and a short period may be configured.

2)drx-onDurationTimer:

Is the period of time that the DRX-onduration timer operates in the active time (or on duration) of DRX in the DRX-cycle1101, and may correspond to the active time 1110 of DRX from the start to the expiration of the DRX-onduration timer 1102. The remaining period of DRX-cycle1101 after the time when DRX-onduration timer 1102 expires may be the inactivity time 1111 of DRX. Part (a) of fig. 11 shows an example in which only a DRX-onduration timer 1102 is defined in side link communication, and an inactive time 1110 and an active time 1111 of DRX are operated.

3)drx-InactivityTimer:

If side link control information on the PSCCH is detected/received (1103) before DRX-onduration timer 1102 expires in DRX-cycle 1101, the active time of DRX may be extended from the time the control information is detected/received to the time the DRX-incaactyitytimer 1104 operates and expires. The remaining period of DRX-cycle 1101 after the time when DRX-inactivity timer1104 expires may be the inactivity time 1111 of DRX. Part (b) of fig. 11 shows an example in which a DRX-onduration timer 1102 and a DRX-incaactytimer 1104 are defined in side link communication, and an inactive time 1110 and an active time 1111 of DRX are operated.

4)drx-HARQ-RTT-Timer:

As shown in part (c) of fig. 11B, when retransmission is performed in the side link communication, DRX-HARQ-round trip time-Timer (DRX-HARQ-RTT) may be triggered in the UE in an active time 1110 of DRX 1101 (1103). As a condition for triggering the drx-HARQ-RTT-Timer 1105 in the side link communication, when the side link control information is received or the side link control information is received and the location information for retransmission is indicated in the side link control information (first SCI), the drx-HARQ-RTT-Timer 1105 may be applied until the next retransmission is received according to the corresponding information. When DRX-HARQ-RTT-Timer 1105 expires, the UE may operate in an active time 1110 of DRX 1101 to receive the retransmission. In this case, as described in detail below, the active time 1110 of the DRX 1101 may be a period during which the DRX-retransmission timer 1106 operates. As described above, since the location information on the initial transmission and retransmission resources (including information on the presence or absence of the retransmission resources) is indicated in the first SCI, the drx-HARQ-RTT-Timer 1105 can be assumed and defined as a time interval between retransmission resources or a time interval between the initial transmission and retransmission resources indicated in the first SCI. If no retransmission resources are indicated in the received first SCI, the drx-HARQ-RTT-Timer 1105 may not operate. Part (c) of fig. 11B shows an example in which a DRX-onduration Timer 1102, a DRX-incaactyl Timer1104, a DRX-HARQ-RTT-Timer 1105, and a DRX-retransmission Timer 1106 are defined in side link communication, and inactive times 1111, 1113 and active times 1110, 1112 of the DRX 1101 are operated.

5)drx-RetransmissionTimer:

In part (c) of fig. 11B, when retransmission is performed in the side link communication, the drx-retransmission Timer 1106 may operate from when the drx-HARQ-RTT-Timer1105 expires. Therefore, the drx-retransmission Timer 1106 does not operate during the period of time that the drx-HARQ-RTT-Timer1105 operates. In side link communication, the drx-retransmission timer 1106 may also be determined as a fixed value of one slot or one subframe. In this case, the drx-retransmission timer 1106 may not be defined. However, the present disclosure is not limited thereto. In other words, in side link communications, drx-retransmission timer 1106 may be set to a value of one or more slots or one or more subframes. Thus, as in part (c) of fig. 11, the period of DRX-retransmission timer 1106 operation may be set to the active time 1112 of DRX 1101 to receive retransmissions from the counterpart UE (peer UE). The remaining DRX-cycle period is set to the inactivity time 1113 of the DRX 1101 so that the UE cannot perform reception of control and data information.

6)drx-SlotOffset:

This may be used to adjust the starting position of DRX applications in side link communications when supporting various subcarrier spacings (SCS).

7) WUS (wake-up signal) period:

As shown in part (d) of fig. 11B, when WUS for saving power of the UE in the side link communication is used, a WUS period may be set. Under the assumption that WUS is transmitted according to the WUS period, the UE may monitor WUS at a location where WUS is transmitted (1107). Part (d) of fig. 11B shows an example of determining the inactivity time and activity time of the DRX 1101 using WUS. If WUS indicates that the UE is not awake in 1107 as shown in part (d) of fig. 11B, the UE does not operate the DRX-onduration timer1102 in the DRX-cycle 1101, and the entire DRX-cycle may be set to the inactivity time 1110 of the DRX 1101. In contrast, when WUS indicates that the UE wakes up in 1107, the UE may perform operations as shown in parts (a) and (B) of fig. 11A or as shown in part (c) of fig. 11B according to the configured DRX parameters.

According to the above description, the active time (or start-up duration) in DRX may be defined under the following conditions. For example, when the DRX cycle is set in the side link communication, the active time (or start-up duration) may correspond to a period when the DRX-onduration timer or DRX-incaivitytimer or DRX-retransmission timer operates.

As described above, some parameters may not be used in the side link DRX, or other parameters may be additionally considered. Note that the parameters may vary depending on the transmission method (e.g., broadcast, unicast, or multicast) in the side link communication. In the present disclosure, the method for setting the parameter information is not limited to a specific method. This information may be (pre) configured and in case of unicast may be configured by PC5-RRC or by side link MAC-CE.

As described above, the UE may not perform monitoring/decoding of the above-described control information and data information in a period set as an inactive time when DRX is applied in side link communication. The control information may include first SCI and second SCI information. As described above, mode 2 sensing in side link communication (i.e., a scheme in which the UE directly allocates/selects transmission resources for side link communication by sensing) is an operation in which the UE monitors the side link channel and includes decoding of PSCCH (in other words, decoding of the first SCI) and SL-RSRP measurement. If monitoring/decoding control information (first SCI and second SCI) is not allowed for data reception in a period of inactivity time set to DRX in side link communication, but monitoring/decoding control information (first SCI) is allowed for resource selection sensing, sensing may be performed in the inactivity time of DRX, so that a UE performing DRX in side link communication may not experience problems when performing the sensing operation described in connection with fig. 7 to 10. However, when neither monitoring/decoding control information for data reception nor monitoring/decoding control information (first SCI) for sensing is allowed in the side link communication in the period of the inactive time set to DRX, a problem related to the mode 2 sensing operation may occur. The following first embodiment teaches UE operation and methods for solving problems that may occur in mode 2 sensing operation. When a Tx UE (peer UE) transmitting side link data to an Rx UE performing a DRX operation performs mode 2 sensing to select resources, the Rx UE needs to be able to receive the data. Therefore, the UE operation needs to be defined in consideration of this situation.

First embodiment

The first embodiment discloses an operation method of mode 2 sensing and resource selection in which neither monitoring/decoding control information (first SCI and second SCI) is allowed for data reception nor monitoring/decoding control information (first SCI) is allowed for sensing in a period set as an inactive time of DRX in a side link. In this case, the UE may not perform sensing in a period set as an inactive time of DRX in the auxiliary link communication. When the UE needs to perform side link DRX and mode 2 sensing, if a period (slot) for performing sensing (refer to a sensing period of fig. 7 to 10) overlaps with an inactive time of DRX, the following method may be regarded as UE operation. It should be noted that the present disclosure is not limited to the following sensing methods, and two or more of the following sensing methods may be combined and used.

Sensing method 1: the sensing period (slot) is adjusted to an active time of the side link DRX to ensure a preset sensing period (slot), and the UE performs sensing in the corresponding sensing period (slot).

The sensing method 2. The ue performs sensing only in a period (slot) corresponding to an active time of the side link DRX in a preset sensing period (slot).

According to the sensing method 2, sensing is performed only when at least a portion of a preset sensing period (slot) corresponds to an active time of the side link DRX. If all preset sensing periods (slots) correspond to inactive times of the side link DRX, sensing may not be performed. To solve this problem, the UE may adjust the time n at which the resource (re) selection is triggered such that a partial sensing period (slot) is included in the active time of the side link DRX. The UE may identify whether a portion of a sensing period (slot) is included in an active time of the sidelink DRX based on the DRX-related configuration information.

Sensing method 3. Ue does not perform sensing. In this case, random selection may be used for resource selection.

Sensing method 4: this is a combination of the sensing method 2 and the sensing method 3, and refer to embodiments 2 and 3 described in detail below.

Sensing method 5: the preset sensing period (slot) is set as an active time of the side link DRX, and the UE performs sensing in the set sensing period (slot).

According to the sensing method 5, it is possible to determine that the sensing period (slot) is set to the active time of the side link DRX such that monitoring/decoding of control information (first SCI) is only allowed for resource selection sensing, and monitoring/decoding of control information (first SCI and second SCI) is not allowed for data reception. Instead, it may be determined that monitoring/decoding of control information (first SCI) is allowed for the purpose of resource selection sensing and monitoring of control information (first SCI and second SCI) is allowed for the purpose of data reception.

If the sensing method 5 allows decoding control information (first SCI and second SCI) for data reception, corresponding information for data transmission/reception between UEs in side link communication may be additionally indicated. In this case, various indication methods may be used. In general, an indication may be provided that the DRX wake up time is matched by the SCI (first SCI or second SCI). In contrast, in unicast, the corresponding indication may be provided by PC5-RRC or side link MAC CE. The method for indication by SCI can be advantageously used for all broadcast, multicast and unicast. The indication method for matching the side link DRX wake-up time in the sensing method 5 can be supported even when it can be determined that the sensing period (slot) is set to the active time of the side link DRX such that decoding of the control information (first SCI) is allowed only for resource selection sensing and monitoring/decoding of the control information (first SCI and second SCI) is not allowed for data reception.

Fig. 12 shows a sensing method 1 of a UE according to an embodiment.

Part (a) of fig. 12 shows an example in which, when full sensing of fig. 7 and continuous partial sensing of fig. 9, and partial sensing and random selection of fig. 10 are performed by the sensing method 1, a sensing period set to perform re-evaluation and preemption is adjusted. According to the sensing method 1, the sensing period can be extended only in the period set as the DRX active time 1201. Part (a) of fig. 12 shows an example in which the sensing period 1200 is set and a portion of the sensing period overlaps with the DRX inactivity time (1202). Part (a) of fig. 12 shows an example in which DRX active times 1201, 1203 and inactive time 1202 are configured, and it should be noted that various active and inactive times of DRX may be generated according to DRX parameters. Since a portion of the sensing period 1200 is set to the inactive period 1202 of the DRX such that sensing cannot be performed in the inactive period 1202 in part (a) of fig. 12, the sensing period may be adjusted to be extended and operated as shown by the sensing window 1204 according to the sensing method 1 to further secure the sensing period. In this case, an extended sensing period may be set in the active time 1203 of the DRX. If the active time period of DRX is discontinuous, the extended sensing period may also be set to discontinuous.

Part (b) of fig. 12 shows an example in which a sensing period (time slot) set to perform the cycle-based partial sensing of the embodiment of fig. 8 is adjusted by the sensing method 1. When DRX is not configured and operated in the side link, the method described in connection with the embodiment of fig. 8 may be used to determine a sensing period (time slot) set to perform cycle-based partial sensing. However, if DRX is operated in side link communication such that a period (slot) in which sensing is performed overlaps with an inactive time of DRX, a sensing period (slot) may be determined according to the sensing method 1. When DRX is not configured and operated in side link communication, the sensing time slot 1200 of part (b) of fig. 12 is set, and the UE may perform sensing in the corresponding time slot 1200. However, if the DRX is operated such that a period (slot) in which sensing is performed in the side link communication overlaps with the inactive time of the DRX (1200), as shown in part (b) of fig. 12, the UE may not perform sensing in the overlapping (1200) period. In this case, in part (b) of fig. 12, the sensing time slot 1203 is adjusted by the sensing method 1 to be set in the active period 1201 of the DRX instead of being set in the overlap period 1200, thereby enabling sensing in the corresponding period. Therefore, when applied to the period-based partial sensing, the sensing method 1 may be interpreted as a method of limiting a period (slot) for performing sensing to be set in an active time of DRX.

According to the sensing method 5, the active time (or start-up duration) in DRX may be set under the following conditions.

When the DRX cycle is set in the side link communication, the condition for setting the active time (or the start-up duration) may include at least one of the following conditions.

Condition 1: when the drx-ondurationTimer or the drx-InactivityTimer or the drx-retransmission Timer is operated

Condition 2: when the sensing period (time slot) operates (when sensing is performed in the sensing period (time slot))

Setting the DRX cycle in the side link communication in the sensing method 5 may be interpreted as performing DRX in the side link communication. An example when the sensing period (slot) operates may be interpreted as a case where the sensing period (slot) is a timer run time of the DRX active time. Note that the method of the first embodiment described above can be applied to the sensing method described in connection with fig. 7 to 10.

Second embodiment

Disclosed in the second embodiment is a UE operation when the sensing methods 2 to 4 described in connection with the first embodiment are applied to a sensing period (slot) set to perform the cycle-based partial sensing of fig. 8. As described above, according to the sensing method 2, sensing is performed only when at least a portion of the preset sensing period (slot) corresponds to the active time of the side link DRX. If all preset sensing periods (slots) correspond to inactive times of the side link DRX, sensing may not be performed. Therefore, for the sensing method 2 to be operable over time, it is necessary to apply the sensing method 3, or as in the sensing method 4, selectively apply the sensing method 2 and the sensing method 3 according to predetermined conditions in the above-described case.

Fig. 13 illustrates sensing methods 2 to 4 of a UE according to an embodiment.

Part (a) of fig. 13 shows an example in which, as described in connection with fig. 8, one slot among the Y candidate slots is referred to1300 (selected to perform cycle-based partial sensing), x=2 monitoring slots 1301 and 1302 are set as slots for performing partial sensing, but the corresponding slots are all included in the inactive time 1310 of the side link DRX. When X (Σ1) monitoring slots are set to perform cycle-based partial sensing but the corresponding slots are included in the inactive time of the side link DRX such that the available sensing period (slot) is not guaranteed, as shown in part (a) of fig. 13, the UE does not perform sensing, and random selection can be used for resource selection, as in sensing method 3.

Part (b) of fig. 13 shows an example according to one of the Y candidate slots as described in connection with fig. 81300 (selected to perform cycle-based partial sensing), x=3 monitoring slots 1301, 1302, and 1303 are set as slots for performing partial sensing, but one slot 1302 of the slots is included in the inactive time 1310 of the side link DRX, and the other two slots 1301 and 1303 are included in the active time of the side link DRX. The X (1) monitoring slots are arranged to perform periodic based partial sensing, but as In the case where only the slots corresponding to Y (1+.y+.x) shown in part (b) of fig. 13 are included in the active time of the side link DRX and are available for sensing, the sensing method 2 may be used or the sensing method 4 may be considered as follows. Specifically, according to the sensing method 2, if the UE performs periodic based partial sensing among Y available sensing slots and X-Y (0) slots that are not available occur, the corresponding slots are not used for sensing.

The sensing method 4 is used to determine under what conditions the sensing method 2 or the sensing method 3 is selected. Specifically, according to the sensing method 4, if Y is N% or more of X, the cycle-based partial sensing is performed in Y slots by the sensing method 2. Otherwise, according to the sensing method 3, sensing is not performed, and random selection may be used for resource selection. N=100 means that when x=y (i.e. when all set monitoring slots are available), this means that sensing method 3 is selected if at least one non-sensing capable slot is caused from the X monitoring slots by the inactivity time of the side link DRX.

In the sensing method 4, N may be fixed to a specific value or settable. When N can be set, a (pre) configured method can be used, and if PC5-RRC is available as in unicast, a method of setting it through PC5-RRC or side link MAC CE can be considered. A method in which N is included in SCI (first SCI or second SCI) and indicated may also be considered. When N is settable, a method of setting N in association with a Channel Busy Ratio (CBR) may also be considered. In side link communication, the UE may measure CBR and as channel congestion increases, the measured CBR value may increase. In general, as channel congestion increases, improved sensing needs to be performed to avoid collisions in resource selection. Thus, it may be supported that N varies depending on CBR value (or CBR level).

The measured CBR value may be mapped to a defined CBR level. Specifically, as the CBR value decreases, a lower N value may be set so that the sensing method 4 may select the sensing method 2 more frequently. In this method, the threshold value of the CBR value may be set to be different according to priority. The threshold value for determining the CBR value of N may be determined by the UE implementation or may be (pre) configured.

As shown in part (b) of FIG. 13, X (. Gtoreq.1) monitoring slots are set to perform periodic based partial sensing. However, in the case where only the slots corresponding to Y (1+.y+.x) are included in the active time of the side link DRX and are available for sensing, the condition of selecting one of the sensing method 2 and the sensing method 3 by the sensing method 4 is not limited only when Y is N% or more of X. For example, as another condition, a case where the activity time in the drx-cycle is N% more can be considered. The active time may be limited to the active time determined by drx-onduration timer. This is why the drx-incavitytimer or drx-retransmission timer can operate context-independent. In this case, the sensing method 2 may be applied when the activity time is N% more in the drx-cycle, otherwise, the sensing method 3 may be applied. This method is disclosed in view of the difficulty of performing sensing when a large amount of active time is not guaranteed in the drx-cycle.

Third embodiment

The third embodiment discloses UE operation when the sensing methods 2 to 4 described in connection with the second embodiment are applied for a sensing period in which re-evaluation and preemption are performed when full sensing of fig. 7, continuous partial sensing of fig. 9, and partial sensing and random selection of fig. 10 are performed.

As described above, according to the sensing method 2, the ue may perform sensing only when at least a portion of the preset sensing period (slot) corresponds to an active time of the side link DRX. The UE may not perform sensing if all preset sensing periods (slots) correspond to inactive times of the side link DRX. Therefore, for the sensing method 2 to be operable over time, it is necessary to apply the sensing method 3, or as in the sensing method 4, selectively apply the sensing method 2 and the sensing method 3 according to predetermined conditions in the above-described case.

Fig. 14 shows sensing methods 2 to 4 according to embodiments.

Part (a) of fig. 14 shows an example in which a sensing period 1401 set to perform re-evaluation and preemption when full sensing of fig. 7 and continuous partial sensing of fig. 9, and partial sensing and random selection of fig. 10 are performed is fully included in an inactive time 1410 of the side link DRX. When a sensing period (slot) of length X is set as shown in part (a) of fig. 14, but a corresponding slot is included in the inactive time of the side link DRX such that an available sensing period (slot) is not guaranteed, sensing is not performed, and random selection may be used for resource selection as in sensing method 3.

Part (b) of fig. 14 shows an example in which only a part of the sensing period 1401 set to perform re-evaluation and preemption when performing the full sensing of fig. 7 and the continuous part sensing of fig. 9 and the partial sensing and random selection of fig. 10 is included in the inactive time 1410 of the side link DRX, and the rest of the sensing period 1401 is included in the active time 1411 of the side link DRX. When the sensing period (slot) of length X is set, but only Y (Y) Where the corresponding length of the slot is available for sensing, sensing method 2 may be used or sensing method 4 may be considered as follows.

Specifically, according to the sensing method 2, if the UE performs monitoring only in the sensing slot corresponding to the length Y and an unavailable area of length X-Y (0) occurs, the corresponding area is not used for sensing. The sensing method 4 is used to determine whether to select the sensing method 2 or the sensing method 3 under predetermined conditions. Specifically, according to the sensing method 4, if Y is N% or more of X, sensing is performed in Y slots by the sensing method 2. Otherwise, according to the sensing method 3, sensing is not performed, and random selection may be used for resource selection. N=100 means that when x=y (i.e., when all set time slots are available), this means that the sensing method 3 is selected if there is an area that cannot be sensed in a sensing period (time slot) of length X by the inactive time of the side link DRX. In the sensing method 4, N may be fixed to a specific value or settable. When N is settable, a (pre) configured method may be used, and if PC5-RRC is available as in unicast, a method of setting it by PC5-RRC or side link MAC CE may be considered. A method in which N is included in SCI (first SCI or second SCI) and indicated can also be considered. When N is settable, a method of setting N in association with CBR may also be considered.

In the side link, the UE may measure CBR, and as channel congestion increases, the measured CBR value may increase. In general, as channel congestion increases, improved sensing needs to be performed to avoid collisions in resource selection. Thus, it may be supported that N varies depending on CBR value (or CBR level). The measured CBR value may be mapped to a defined CBR level). Specifically, as the CBR value decreases, a lower N value may be set so that the sensing method 4 may select the sensing method 2 more frequently. In this method, the threshold value of the CBR value may be set to be different according to priority. The threshold value for determining the CBR value of N may be determined by the UE implementation or may be (pre) configured. In part (b) of fig. 14, a sensing period (slot) of length X is set. However, when only the sensing period (slot) corresponding to the length of Y (y+.x) is included in the active time of the side link DRX and is available for sensing, the condition of selecting one of the sensing method 2 and the sensing method 3 by the sensing method 4 is not limited only when Y is N% or more of X. For example, as another condition, it can be considered when the activity time is N% more in drx-cycle. The active time may be limited to the active time determined by Drx-onduration timer. This is why the drx-incavitytimer or drx-retransmission timer may or may not be running depending on the context. In this case, the sensing method 2 may be applied when the active time is N% more in the drx-cycle. Otherwise, the sensing method 3 may be applied. This method is disclosed in view of the difficulty of performing sensing when a large amount of active time is not guaranteed in the drx-cycle.

Fourth embodiment

In the fourth embodiment, when the above-described mode 2 sensing (i.e., a scheme in which the UE directly allocates/selects transmission resources for side link communication by sensing) is performed to select resources to the Tx UE transmitting side link data to the Rx UE performing the DRX operation, the Rx UE needs to be able to receive the data. Therefore, it is necessary to define the UE operation in consideration of this situation. In other words, when DRX is operated in side link communication, different operations of defining the UE to determine the resource selection window are required, unlike when DRX is not operated in side link communication.

Specifically, if UE B transmits side link data to UE a in a period in which UE a operates in DRX inactivity time in side link communication, UE a may not receive the side link data. Thus, in performing mode 2 sensing to select resources, a Tx UE (peer UE) transmitting side link data to an Rx UE performing DRX needs to determine a resource selection window to allow the Rx UE to receive the transmitted data. Thus, the following method may be regarded as UE operation. It should be noted that the present disclosure is not limited to the following resource selection methods, and two or more of the following resource selection methods may be combined and used.

Resource selection method 1: the resource selection window is adjusted to the active time of the side link DRX and the UE selects resources in the corresponding time period (slot).

According to resource selection method 1, even as described in connection with FIG. 7, the resource selection window [ n+T ] ₁ ,n+T ₂ ]The UE may also select T within a range that meets the remaining Packet Delay Budget (PDB) when adjusting to the active time of the side link DRX ₂ . According to the resource selection method 1, the Rx UE can receive the corresponding transmission only when the side link DRX is operated and only during the active time of the DRX, compared to when the UE determines the resource selection window when the side link DRX is not operated, and thus the length of the resource selection window determined by the UE can be adjusted. Such a problem may occur in which the resource selection window is adjusted to the active time of DRX due to the PDB, so that an optional resource candidate cannot be guaranteed. To this end, the UE may adjust the time n of the resource (re) selection trigger such that the resource selection window comprises at least the active time of the side link DRX.

In the resource selection method 1, if the resource selection window is adjusted to the active time of the side link DRX such that there is no optional PSSCH resource, the Tx UE may select a transmission resource in the exception pool. In this case, the exception pool may be understood as a resource pool in which the side link transmission/reception is always possible independently of the side link DRX. The exception pool may be understood as a pre-configured temporary resource pool other than the (pre) configured side link resource pool described above, such that side link transmission/reception may be independent of DRX. As another example, if the available resources for side link communication are sufficient, the UE may also be allocated resources using a configured authorization scheme to ensure resource allocation by the exception pool. The resource selection in the exception pool may be performed with random selection without sensing performed by the UE. The above-described operation of the Tx UE transmitting SCI including resource allocation information to the Rx UE through the PSCCH may be performed in the same manner even when the resources are selected using the exception pool. The exception pool may be configured by at least one of RRC information, SIB information or other higher layer signaling information or DCI, SCI information or other L1 signaling information. Thus, when there are no resources within the resource selection window that the UE can select or reselect, an exception pool may be used.

The resource selection method 2. The ue determines a resource selection window without considering the side link DRX and selects resources only in a corresponding region as an active time of the DRX in a corresponding period (slot).

According to resource selection method 2, a resource selection window [ n+T ] may be determined as described in connection with FIG. 7 ₁ ,n+T ₂ ]. The selectable resource candidates only occur when at least a portion of the resource selection window corresponds to an active time of the sidelink DRX. Such a problem may occur where there are no alternative resource candidates, if the entire resource selection window corresponds to the inactivity time of the sidelink DRX. To this end, the UE may adjust the time n of the resource (re) selection trigger such that the resource selection window comprises at least the active time of the side link DRX.

In the resource selection method 2, if resources need to be selected only in the corresponding region as the active time of DRX in the resource selection window, if there is no optional PSSCH resource, the Tx UE may select transmission resources in the exception pool. In this case, the exception pool may be understood as a pool capable of always side link transmission/reception independently of side link DRX. The exception pool may be understood as a pre-configured temporary resource pool in addition to the side link resource pool configured by the (pre) configuration described above, so that the side link transmission/reception may be independent of DRX. As another example, if the available resources for side link communication are sufficient, the UE may also be allocated resources using a configured authorization scheme to ensure resource allocation by the exception pool. The resource selection in the exception pool may be performed with random selection without performing sensing. The above-described operation of the Tx UE transmitting SCI including resource allocation information to the Rx UE through the PSCCH may be performed in the same manner even when the resources are selected using the exception pool. The exception pool may be configured by at least one of RRC information, SIB information or other higher layer signaling information or DCI, SCI information or other L1 signaling information. Thus, when there are no resources within the resource selection window that the UE can select or reselect, an exception pool may be used.

The resource selection method 3. The UE determines a resource selection window without considering the side link DRX and defines a corresponding period (slot) as an active time of the side link DRX, and the UE selects resources only in the determined resource selection window region.

According to the resource selection method 3, the active time for setting the resource selection window to the side link DRX may also be determined to allow monitoring/decoding control information (first SCI) for resource selection sensing and control information (first SCI and second SCI) for data reception. Corresponding information for data transmission/reception between UEs in side link communication may be additionally indicated. In this case, various indication methods may be used. In general, an indication can be made that the DRX wake up time is matched by SCI (first SCI or second SCI). In contrast, in unicast, a corresponding indication may be made by PC5-RRC or by a side link MAC CE. However, the method indicated by SCI can be advantageously used for all broadcast, multicast and unicast.

According to the resource selection method 3, the active time (or the start-up duration) in DRX may be defined under the following conditions.

When the DRX cycle is set in the side link communication, the condition for setting the active time (or the start-up duration) may include at least one of the following conditions.

Condition 1: when the drx-ondurationTimer or the drx-InactivityTimer or the drx-retransmission Timer is operated

Condition 2: when the resource selection window operates (when the resource selection window for resource selection is configured)

Setting the DRX cycle in the side link communication in the resource selection method 3 may be interpreted as performing DRX in the side link communication. An instance when the resource selection window operates may be interpreted as a case where the corresponding resource selection window is the timer run time of the DRX active time.

When the cycle-based partial sensing is performed as shown in fig. 8, Y (1) candidate slots may be selected in the resource selection window 801. In this case, Y candidate slots may be continuously or discontinuously selected in the time domain in the resource selection window. The minimum value of Y may be (pre) configured. The final choice of the Y value and which slot to select may be determined by the UE implementation. When Y (. Gtoreq.1) candidate slots are selected in the resource selection window 801 when configuring and operating the side link DRX, selection needs to be made among slots corresponding to the active time of the side link DRX.

Fig. 15 illustrates an operation of a UE for sensing and resource selection when DRX is performed in side link communication according to an embodiment.

Specifically, fig. 15 shows four UEs (UE 1 to UE 4) performing transmission/reception in the side link. Fig. 15 shows an example in which UE1 is a UE performing side link data transmission (i.e., PSSCH transmission) to UE2, and UE2 is a UE performing side link DRX. As described in connection with the fourth embodiment, if UE1 transmits side link data to UE2 in a period in which UE2 operates in DRX inactivity time in side link communication, UE2 may not receive the side link data. Thus, in performing mode 2 sensing to select resources, in step 1501, a peer UE (UE 1) transmitting side link data to a UE (UE 2) performing DRX needs to determine (or adjust) a resource selection window to allow the Rx UE (UE 2) to receive the transmitted data. In various methods, a UE performing transmission/reception in a side link may be configured with whether DRX and DRX-related parameters are configured. For example, when (pre) configured or in case of unicast, the corresponding information may be configured by PC5-RRC or MAC CE. In step 1502, UE1 may select resources in the resource selection window determined in step 1501 and transmit side link data to UE2 over the PSCCH/PSSCH. For details, reference is made to the fourth embodiment in fig. 15. Although the steps of the present disclosure in connection with the fourth embodiment shown in fig. 15 are focused on the case of mode 2, even in the case of mode 1, if the base station allocates resources to UE1 and the Rx UE (i.e., UE 2) is performing DRX, the base station needs to grasp DRX state information of UE2 and allocate resources in DRX active time of UE 2. For this, the base station needs to know DRX state information (e.g., whether DRX is configured and DRX related parameters) of the UE. As described in connection with fig. 4, in the case of mode 1, the UE may additionally transmit information to the base station that may assist in base station scheduling. This may be done through RRC messages or MAC CEs. In the present disclosure, the method for indicating the corresponding information is not limited thereto. The corresponding information may be referred to as ueassistance information. The base station may generally configure the DRX state information cell-commonly, and the base station may assume a corresponding configuration. In contrast, when the base station cannot adjust the corresponding configuration (e.g., when the corresponding information is configured through the PC5-RRC or MAC CE in the case of unicast), the UE may include DRX state information in the UE assumability information and indicate the information to the base station. In the case of mode 1, the base station needs to receive DRX configuration information of the UE and perform mode 1 scheduling, and the UE may accordingly expect the base station to perform mode 1 scheduling with DCI.

In fig. 15, when UE2 is performing side link DRX, sensing may not be possible in the inactive time of side link DRX. As described in connection with the first to third embodiments, the UE2 may not perform the sensing step when the entire sensing period (slot) is the inactive time of DRX. Thus, as in step 1503, the UE2 does not perform sensing, or needs to determine/adjust a sensing period (slot) in the active time of DRX. When the sensing period (time slot) is determined as the active time of DRX, UE2 may monitor the PSCCH (first SCI) of another UE (UE 3) in the sensing period as in step 1504. For details of these steps, please refer to the first to third embodiments. Fig. 15 shows an example in which UE3 is a UE performing side link data transmission (i.e., PSSCH transmission) to UE4, and UE4 is a UE not performing side link DRX. In this case, unlike in step 1501, the UE3 may determine a resource selection window and select resources without considering DRX of the Rx UE and transmit side link data to the UE4 through PSCCH/PSSCH in step 1505.

Fig. 16 illustrates an internal structure of a UE according to an embodiment of the present disclosure.

Referring to fig. 16, a UE may include a UE receiver 1600, a UE transmitter 1604, and a UE processor 1602. The UE receiver 1600 and the UE transmitter 1604 may be collectively referred to as a transceiver. The UE processor 1602 may control the sensing operation and/or the resource selection operation according to the above-described embodiments, and the UE processor 1602 may be referred to as a controller or processor. The UE processor 1602 may transmit/receive signals to/from a base station through a transceiver. The UE processor 1602 may transmit/receive signals to/from a counterpart UE in side link communication through a transceiver. The signals may include control information and data. To this end, the transceiver may include a Radio Frequency (RF) transmitter for up-converting and amplifying the transmitted signal, and an RF receiver for low noise amplifying the received signal and down-converting the frequency of the received signal. The transceiver may receive signals via a radio channel, output signals to the UE processor 1602, and transmit signals output from the UE processor 1602 via the radio channel. The UE processor 1602 may control a sequence of processes that the UE is capable of operating in accordance with the embodiments described above.

Fig. 17 shows an internal structure of a base station according to an embodiment.

Referring to fig. 17, a base station may include a base station receiver 1701, a base station transmitter 1705, and a base station processor 1703. The base station receiver 1701 and the base station transmitter 1705 may be collectively referred to as a transceiver. The base station processor 1703 may provide DRX-related configuration information to the UE and schedule side-link resources to consider the DRX operation of the UE and provide scheduled resource allocation information to the UE when performing the above-described mode 1 operation (base station allocates transmission resources in side-link communication). In this case, the UE may expect the base station to allocate the mode 1 resource in consideration of DRX. The base station processor 1703 may transmit/receive signals to/from the UE through a transceiver. The signals may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying the transmitted signal, and an RF receiver for low noise amplifying the received signal and down-converting the frequency of the received signal. The transceiver may receive signals via a radio channel, output signals to the base station processor 1703, and transmit signals output from the base station processor 1703 via the radio channel. The base station processor 1703 may control the base station to be able to operate a series of processes according to the above-described embodiments.

It will be understood that each block of the flowchart illustrations, and combinations of flowcharts, can be implemented by computer program instructions. Because computer program instructions may be provided in a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions described in conjunction with the blocks of each flowchart. Because computer program instructions may be stored in a computer-usable or computer-readable memory and may be directed to a computer or other programmable data processing apparatus to function in a particular manner, the instructions stored in the computer-usable or computer-readable memory may produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks. Because computer program instructions may be provided in a computer or other programmable data processing apparatus, the instructions which produce a process implemented process such that the instructions which execute on the computer or other programmable data processing apparatus create means for implementing the functions specified in the flowchart block or blocks.

Each block may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the block may occur out of the order. For example, two blocks shown in succession may be executed substantially concurrently or the blocks may be executed in the reverse order, depending upon the functionality involved.

Although the present disclosure has been described with reference to various embodiments, various changes may be made without departing from the spirit and scope of the disclosure, which is not limited by the detailed description and embodiments, but by the appended claims and their equivalents.

Claims (14)

1. A method for transmitting side link data by a first user equipment UE in a wireless communication system supporting side link communication between a first user equipment UE and a second UE, the method comprising: identifying configuration information including information associated with discontinuous reception DRX of the sidelink communications; and In the case where the second UE performs a DRX operation, sending the side link data to the second UE within a DRX activity time, the DRX activity time of the second UE being identified based on the configuration information . 2. The method of claim 1, wherein identifying the configuration information includes by using radio resource control of a PC5 interface for the side link communication between the first UE and the second UE. RRC configuration to obtain the configuration information. 3. The method of claim 1, wherein the configuration information includes information indicating whether DRX is configured for the side link communication. 4. The method of claim 1, further comprising: Determine a resource selection window based on the DRX activity time of the second UE; and The resource selection window is used to select a resource for transmitting the side link data. 5. The method of claim 1, wherein resources for transmitting the sidelink data are selected within the DRX active time of the second UE. 6. The method of claim 1, further comprising selecting resources for transmitting the side-link data by using a sensing scheme in which the UE directly selects transmission resources for side-link communication. 7. The method of claim 1, wherein information associated with the DRX includes at least one of the following: information about the DRX cycle, which indicates the period of time during which said DRX is applied, information regarding a DRX on duration timer indicating the duration of said active time in said DRX cycle, Information regarding a DRX inactivity timer indicating an extended duration of the activity time when sidelink control information is detected before the expiration of the DRX on persistence timer, and Wherein, the activity time corresponds to the time period during which the DRX on-continuation timer or the DRX inactivity timer operates. 8. A first user equipment UE, configured to send side link data in a wireless communication system that supports side link communication between the first UE and the second UE, the first UE comprising: transceiver; and Processor, configured as: identifying configuration information including information associated with discontinuous reception DRX of the sidelink communications; and In the case where the second UE performs a DRX operation, the side link data is sent to the second UE via the transceiver within a DRX activity time, the DRX activity time of the second UE is based on the identified by the above configuration information. 9. A first UE according to claim 8, adapted to operate according to one of claims 2 to 7. 10. A method for receiving sidelink data by a second UE in a wireless communication system supporting sidelink communication between a first user equipment UE and a second UE, the method comprising: identifying configuration information including information associated with discontinuous reception DRX of the sidelink communications; and In the case where the second UE performs a DRX operation, the side link data is received from the first UE within a DRX activity time, and the DRX activity time of the second UE is determined based on the configuration information. Identify. 11. The method of claim 10, wherein identifying the configuration information includes by using radio resource control of a PC5 interface for the sidelink communication between the first UE and the second UE. RRC configuration to obtain the configuration information. 12. The method of claim 10, wherein the sidelink data is received using allocated resources within the DRX active time of the second UE. 13. A second user equipment UE, configured to receive side link data in a wireless communication system supporting side link communication between a first UE and the second UE, the second UE comprising: transceiver; and Processor, configured as: identifying configuration information including information associated with discontinuous reception DRX of the sidelink communications; and In the case where the second UE performs a DRX operation, the side link data is received from the first UE within a DRX activity time, and the DRX activity time of the second UE is determined based on the configuration information. Identify. 14. A second UE according to claim 13, adapted to operate according to one of claims 11 and 12.