User equipments, and communication methods

Abstract

A method performed by a user equipment (UE) is described. The method includes receiving, from a higher layer of the UE, a first parameter and a second parameter for a PSSCH transmission in a resource pool, the first parameter indicating a number of sub-channels, the second parameter indicating a number of RB sets, L RBSET; and determining candidate resources within a time interval for the PSSCH transmission, wherein a candidate resource Rr,x,y is defined as a set of one or more contiguous sub-channels starting from a sub-channel with index x in a slot with index y in the L RBSET contiguous RB sets starting from an RB set with index r, and the number of one or more contiguous sub-channels is determined at least based on the first parameter.

Description

[DxSCRIPTION][Title of Invention]USER EQUIPMENTS, AND COMMUNICATION METHODS[Technical Field]

[0001] The present disclosure relates to a user equipment, and a communication method.[Background Art]

[0002] At present, as a radio access system and a radio network technology aimed for the fifth generation cellular system, technical investigation and standard development are being conducted, as extended standards of Long Term Evolution (LTE), on LTE-Advanced Pro (LTE-A Pro) and New Radio technology (NR) in The Third Generation Partnership Project (3GPP).

[0003] In the fifth generation cellular system, three services of enhanced Mobile BroadBand (eMBB) to achieve high-speed and large-volume transmission, UltraReliable and Low Latency Communication (URLLC) to achieve low-latency and high- reliability communication, and massive Machine Type Communication (mMTC) to allow connection of a large number of machine type devices such as Internet of Things (loT) have been demanded as assumed scenarios.

[0004] For example, wireless communication devices may communicate with one or more device. For sidelink communication, two communication devices can communicate with each other via PC-5 interface. However, given the existing sidelink communication methods cannot directly applied to unlicensed spectrum, the flexibility and / or the efficiency of the whole sidelink communication system would be limited. As illustrated by this discussion, systems and methods according to the present invention, supporting sidelink communication over unlicensed spectrum, which may improve the communication flexibility and / or efficiency, would be beneficial.[Brief Description of the Drawings]

[0005] Figure 1 is a block diagram illustrating one configuration of one or more base stations and one or more user equipments (UEs) in which systems and methods for determination of candidate resources in a resource pool for SL transmissions may be implemented;

[0006] Figure 2 is a diagram illustrating one example 200 of a resource grid;

[0007] Figure 3 is a diagram illustrating one example 300 of common resource block grid, carrier configuration and B WP configuration by a UE 102 and a base station 160;

[0008] Figure 4 is a diagram illustrating one 400 example of CORESET configuration in a BWP by a UE 102 and a base station 160;

[0009] Figure 5 is a diagram illustrating one example 500 of interlaced transmission and reception in a BWP;

[0010] Figure 6 is a diagram illustrating one example 600 of a SL BWP and a resource pool within the SL BWP;

[0011] Figure 7 is a diagram illustrating one example 700 of a resource pool configuration;

[0012] Figure 8 is a diagram illustrating one example 800 of configurations of a SL BWP and SL resource pools;

[0013] Figure 9 is a diagram illustrating one example 900 of sub-channel determination in a resource pool by a UE 102;

[0014] Figure 10 is a flow diagram illustrating one implementation of a method 1000 for determination of candidate resources in a procedure of sensing and resource selection in a resource pool by a UE 102;

[0015] Figure 11 illustrates various components that may be utilized in a UE;

[0016] Figure 12 illustrates various components that may be utilized in a base station;[Description of Embodiments]

[0017] A user equipment (UE) is described. The UE includes reception unit configured to receive, from a higher layer of the UE, a first parameter and a second parameter for a PSSCH transmission in a resource pool, the first parameter indicating a number of sub-channels, the second parameter indicating a number of RB sets, ZRBSET; and control unit configured to determine candidate resources within a time interval for the PSSCH transmission, wherein a candidate resource is identified by a symbol Rr,x,ywherein a candidate resource Rr,x,yis defined as a set of one or more contiguous sub- channels starting from a sub-channel with index x in a slot with index y in the ZRBSET contiguous RB sets starting from an RB set with index r, and the number of one or more contiguous sub-channels is determined at least based on the first parameter.

[0018] A communication method performed by a user equipment (UE) is described. The method includes receiving, from a higher layer of the UE, a first parameter and a second parameter for a PSSCH transmission in a resource pool, the first parameter indicating a number of sub-channels, the second parameter indicating a number of RB sets, ZRBSET; and determining candidate resources within a time interval for the PSSCH transmission, wherein a candidate resource Rr,x,yis defined as a set of one or more contiguous sub-channels starting from a sub-channel with index x in a slot with index y in the ZRBSET contiguous RB sets starting from an RB set with index r, and the number of one or more contiguous sub-channels is determined at least based on the first parameter.

[0019] 3 GPP Long Term Evolution (LTE) is the name given to a project to improve the Universal Mobile Telecommunications System (UMTS) mobile phone or device standard to cope with future requirements. In one aspect, UMTS has been modified to provide support and specification for the Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN). 3GPP NR (New Radio) is the name given to a project to improve the LTE mobile phone or device standard to cope with future requirements. In one aspect, LTE has been modified to provide support and specification (TS 38.331, 38.321, 38.300, 37.340, 38.211, 38.212, 38.213, 38.214, etc.) for the New Radio Access (NR) and Next generation - Radio Access Network (NG-RAN).

[0020] At least some aspects of the systems and methods disclosed herein may be described in relation to the 3 GPP LTE, LTE- Advanced (LTE- A), LTE-Advanced Pro, New Radio Access (NR), and other 3G / 4G / 5G standards (e.g., 3GPP Releases 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and / or 18, and / orNarrow Band-Internet of Things (NB-IoT)). However, the scope of the present disclosure should not be limited in this regard. At least some aspects of the systems and methods disclosed herein may be utilized in other types of wireless communication systems.

[0021] A wireless communication device may be an electronic device used to communicate voice and / or data to a base station, which in turn may communicate with a network of devices (e.g., public switched telephone network (PSTN), the Internet, etc.). In describing systems and methods herein, a wireless communication device may alternatively be referred to as a mobile station, a UE (User Equipment), an accessterminal, a subscriber station, a mobile terminal, a remote station, a user terminal, a terminal, a subscriber unit, a mobile device, a relay node, etc. Examples of wireless communication devices include cellular phones, smart phones, personal digital assistants (PDAs), laptop computers, netbooks, e-readers, wireless modems, industrial wireless sensors, video surveillance, wearables, vehicles, roadside units, infrastructure devices, etc. In 3 GPP specifications, a wireless communication device is typically referred to as a UE. However, as the scope of the present disclosure should not be limited to the 3 GPP standards, the terms “UE” and “wireless communication device” may be used interchangeably herein to mean the more general term “wireless communication device”.

[0022] In 3GPP specifications, a base station is typically referred to as a gNB, a Node B, an eNB, a home enhanced or evolved Node B (HeNB) or some other similar terminology. As the scope of the disclosure should not be limited to 3GPP standards, the terms “base station,”, “gNB”, “Node B,” “eNB,” and “HeNB” may be used interchangeably herein to mean the more general term “base station.” Furthermore, one example of a “base station” is an access point. An access point may be an electronic device that provides access to a network (e.g,, Local Area Network (LAN), the Internet, etc.) for wireless communication devices. The term “communication device” may be used to denote both a wireless communication device and / or a base station.

[0023] It should be noted that as used herein, a “cell” may be any communication channel that is specified by standardization or regulatory bodies to be used for International Mobile Telecommunications-Advanced (IMT-Advanced), IMT-2020 (5G) and all of it or a subset of it may be adopted by 3GPP as licensed bands (e.g., frequency bands) to be used for communication between a base station and a UE. It should also be noted that in NR, NG-RAN, E-UTRA and E-UTRAN overall description, as used herein, a “cell” may be defined as “combination of downlink and optionally uplink resources.” The linking between the carrier frequency of the downlink resources and the carrier frequency of the uplink resources may be indicated in the system information transmitted on the downlink resources.

[0024] “Configured cells” are those cells of which the UE is aware and is allowed by a base station to transmit or receive information. “Configured cell(s)” may be serving cell(s). The UE may receive system information and perform the required measurements on configured cells. “Configured cell(s)” for a radio connection mayconsist of a primary cell and / or no, one, or more secondary cell(s). “Activated cells” are those configured cells on which the UE is transmitting and receiving. That is, activated cells are those cells for which the UE monitors the physical downlink control channel (PDCCH) and in the case of a downlink transmission, those cells for which the UE decodes a physical downlink shared channel (PDSCH). “Deactivated cells” are those configured cells that the UE is not monitoring the transmission PDCCH. It should be noted that a “cell” may be described in terms of differing dimensions. For example, a “cell” may have temporal, spatial (e.g., geographical) and frequency characteristics.

[0025] The base stations may be connected by the NG interface to the 5G - core network (5G-CN). 5G-CN may be called as to NextGen core (NGC), or 5G core (5GC). The base stations may also be connected by the SI interface to the evolved packet core (EPC). For instance, the base stations may be connected to a NextGen (NG) mobility management function by the NG-2 interface and to the NG core User Plane (UP) functions by the NG-3 interface. The NG interface supports a many-to-many relation between NG mobility management functions, NG core UP functions and the base stations. The NG-2 interface is the NG interface for the control plane and the NG-3 interface is the NG interface for the user plane. For instance, for EPC connection, the base stations may be connected to a mobility management entity (MME) by the Sl- MME interface and to the serving gateway (S-GW) by the Sl-U interface. The SI interface supports a many-to-many relation between MMEs, serving gateways and the base stations. The SI -MME interface is the SI interface for the control plane and the S 1 -U interface is the S 1 interface for the user plane. The Uu interface is a radio interface between the UE and the base station for the radio protocol.

[0026] The radio protocol architecture may include the user plane and the control plane. The user plane protocol stack may include packet data convergence protocol (PDCP), radio link control (RLC), medium access control (MAC) and physical (PHY) layers. A DRB (Data Radio Bearer) is a radio bearer that carries user data (as opposed to control plane signaling). For example, a DRB may be mapped to the user plane protocol stack. The PDCP, RLC, MAC and PHY sublayers (terminated at the base station 460a on the network) may perform functions (e.g., header compression, ciphering, scheduling, ARQ and HARQ) for the user plane. PDCP entities are located in the PDCP sublayer. RLC entities may be located in the RLC sublayer. MAC entitiesmay be located in the MAC sublayer. The PHY entities may be located in the PHY sublayer.

[0027] The control plane may include a control plane protocol stack. The PDCP sublayer (terminated in base station on the network side) may perform functions (e.g., ciphering and integrity protection) for the control plane. The RLC and MAC sublayers (terminated in base station on the network side) may perform the same functions as for the user plane. The Radio Resource Control (RRC) (terminated in base station on the network side) may perform the following functions. The RRC may perform broadcast functions, paging, RRC connection management, radio bearer (RB) control, mobility functions, UE measurement reporting and control. The Non-Access Stratum (NAS) control protocol (terminated in MME on the network side) may perform, among other things, evolved packet system (EPS) bearer management, authentication, evolved packet system connection management (ECM)-IDLE mobility handling, paging origination in ECM-IDLE and security control.

[0028] Signaling Radio Bearers (SRBs) are Radio Bearers (RB) that may be used only for the transmission of RRC and NAS messages. Three SRBs may be defined. SRJBO may be used for RRC messages using the common control channel (CCCH) logical channel. SRB1 may be used for RRC messages (which may include a piggybacked NAS message) as well as for NAS messages prior to the establishment of SRB2, all using the dedicated control channel (DCCH) logical channel. SRB2 may be used for RRC messages which include logged measurement information as well as for NAS messages, all using the DCCH logical channel. SRB2 has a lower priority than SRB1 and may be configured by a network (e.g., base station) after security activation. A broadcast control channel (BCCH) logical channel may be used for broadcasting system information. Some of BCCH logical channel may convey system information which may be sent from the network to the UE via BCH (Broadcast Channel) transport channel. BCH may be sent on a physical broadcast channel (PBCH). Some of BCCH logical channel may convey system information which may be sent from the network to the UE via DL-SCH (Downlink Shared Channel) transport channel. Paging may be provided by using paging control channel (PCCH) logical channel.

[0029] System information may be divided into the MasterlnformationBlock (MIB) and a number of SystemlnformationBlocks (SIBs).

[0030] The UE may receive one or more RRC messages from the base station to obtain RRC configurations or parameters. The RRC layer of the UE may configure RRC layer and / or lower layers (e.g., PHY layer, MAC layer, RLC layer, PDCP layer) of the UE according to the RRC configurations or parameters which may be configured by the RRC messages, broadcasted system information, and so on. The base station may transmit one or more RRC messages to the UE to cause the UE to configure RRC layer and / or lower layers of the UE according to the RRC configurations or parameters which may be configured by the RRC messages, broadcasted system information, and so on.

[0031] The size of various fields in the time domain is expressed in time units . The constantK = TSK= (Aand.

[0032] Multiple OFDM numerologies are supported as given by Table 4.2-1 of [TS 38.211] where p and the cyclic prefix for a bandwidth part are obtained from the higher- layer parameter sub carrier Spacing and cyclicPrefix, respectively.

[0033] The size of various fields in the time domain may be expressed as a number of time units 71=1 / (15000x2048) seconds. Downlink and uplink transmissions are organized into frames with duration, eachconsisting of ten subframes of duration. Thenumber of consecutive OFDM symbols per subframe isEach frame is divided into two equally-sized halfframes of five subframes each with half-frame 0 consisting of subframes 0 -4 and halfframe 1 consisting of subframes 5 - 9.

[0034] For subcarrier spacing (SCS) configuration p, slots are numbered— 1} in increasing order within a subframe and} in increasing order within a frame.ijsthe number ofslots per subframe for subcarrier spacing configurationJM. There areconsecutive OFDM symbols in a slot where depends on the cyclic prefix as given by Tables4.3.2-1 and 4.3.2-2 of [TS 38.211]. The start of slot ry in a subframe is aligned in time with the start of OFDM symbol in the same subframe. Subcarrier spacingrefers to a spacing (or frequency bandwidth) between two consecutive subcarriers inthe frequency domain. For example, the subcarrier spacing can be set to 15kHz (i.e., ^=0), 30kHz (i.e. μ=1), 60kHz (i.e. μ=2), 120kHz (i.e. μ=3), or 240kHz (i.e. μ=4). A resource block is defined as a number of consecutive subcarriers (e.g., 12) in the frequency domain. For a carrier with different frequency, the applicable subcarrier may be different. For example, for a carrier in a frequency rang 1, a subcarrier spacing only among a set of {15kHz, 30kHz, 60kHz} is applicable. For a carrier in a frequency rang 2, a subcarrier spacing only among a set of {60kHz, 120kHz, 240kHz} is applicable. The base station may not configure an inapplicable subcarrier spacing for a carrier.

[0035] OFDM symbols in a slot can be classified as 'downlink', 'flexible', or 'uplink'. Signaling of slot formats is described in subclause 11.1 of [TS 38.213],

[0036] In a slot in a downlink frame, the UE may assume that downlink transmissions only occur in 'downlink' or 'flexible' symbols. In a slot in an uplink frame, the UE may only transmit in 'uplink' or 'flexible' symbols.

[0037] Various examples of the systems and methods disclosed herein are now described with reference to the Figures, where like reference numbers may indicate functionally similar elements. The systems and methods as generally described and illustrated in the Figures herein could be arranged and designed in a wide variety of different implementations. Thus, the following more detailed description of several implementations, as represented in the Figures, is not intended to limit scope, as claimed, but is merely representative of the systems and methods.

[0038] Figure 1 is a block diagram illustrating one configuration of one or more base stations 160 (e.g., eNB, gNB) and one or more user equipments (UEs) 102 in which systems and methods for determination of candidate resources in a resource pool for SL transmissions may be implemented. The one or more UEs 102 may communicate with one or more base stations 160 using one or more antennas 122a-n. For example, a UE 102 transmits electromagnetic signals to the base station 160 and receives electromagnetic signals from the base station 160 using the one or more antennas 122a- n. The base station 160 communicates with the UE 102 using one or more antennas 180a-n. Additionally, one or more UEs 102 may communicate with one or more UEs 102 using one or more antennas 122a-n. For example, a UE 102 transmits electromagnetic signals to another UE(s) 102 and receives electromagnetic signals from another UE(s) 102 using the one or more antennas 122a-n. That is, one or more UEs communicate with each other via sidelink communication.

[0039] The UEs 102 may directly communicate with each other by using the sidelink communication. For illustration, UE(s) 102 capable of sidelink communication include a UE 1A, a UE IB and aUE 1C. The UE 1 Amay be located within the coverage of the base station 160. The UE IB and the UE 1C may be located outside the coverage of the base station 160. The UE 1A and the base station 160 may communicate with each other via downlink and uplink communication. In addition, the UE 1 A and the UE IB may directly communicate with each other via sidelink communication. In addition, the UE I B and the UE 1C may directly communicate with each other via sidelink communication.

[0040] It should be noted that in some configurations, one or more of the UEs 102 described herein may be implemented in a single device. For example, multiple UEs 102 may be combined into a single device in some implementations. Additionally or alternatively, in some configurations, one or more of the base stations 160 described herein may be implemented in a single device. For example, multiple base stations 160 may be combined into a single device in some implementations. In the context of Figure 1, for instance, a single device may include one or more UEs 102 in accordance with the systems and methods described herein. Additionally or alternatively, one or more base stations 160 in accordance with the systems and methods described herein may be implemented as a single device or multiple devices.

[0041] The UE 102 and the base station 160 may use one or more channels 119, 121 to communicate with each other. For example, a UE 102 may transmit information or data to the base station 160 using one or more uplink (UL) channels 121 and signals. Examples of uplink channels 121 include a physical uplink control channel (PUCCH) and a physical uplink shared channel (PUSCH), etc. Examples of uplink signals include a demodulation reference signal (DMRS) and a sounding reference signal (SRS), etc. The one or more base stations 160 may also transmit information or data to the one or more UEs 102 using one or more downlink (DL) channels 119 and signals, for instance. Examples of downlink channels 119 include a PDCCH, a PDSCH, etc. A PDCCH can be used to schedule DL transmissions on PDSCH and UL transmissions on PUSCH, where the Downlink Control Information (DCI) on PDCCH includes downlink assignment and uplink scheduling grants. A PDCCH can be also used for scheduling of sidelink transmissions on PSCCH and PSSCH in one cell, where the Downlink Control Information (DCI) on PDCCH includes sidelink scheduling grants. The PDCCH is usedfor transmitting Downlink Control Information (DCI) in a case of downlink radio communication (radio communication from the base station to the UE). Here, one or more DCIs (may be referred to as DCI formats) are defined for transmission of downlink control information. Information bits are mapped to one or more fields defined in a DCI format. Examples of downlink signals include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a cell-specific reference signal (CRS), a non-zero power channel state information reference signal (NZP CSI-RS), and a zero-power channel state information reference signal (ZP CSI- RS), etc. Other kinds of channels or signals may be used.

[0042] For the UE(s) 102 capable of sidelink communication, the UEs 102 may use one or more sidelink channels 123 to communicate with each other. For example, a UE 102 may transmit information or data to another UE 102 using one or more sidelink (SL) channels 123 and signals. Examples of sidelink channels 123 include a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), a physical sidelink feedback channel (PSFCH), and a physical sidelink broadcast channel (PSBCH). Examples of sidelink signals include a demodulation reference signal (DMRS), a phase-tracking reference signal (PT-RS), a channel-state information reference signal (CSI-RS), a sidelink primary synchronization signal (S-PSS), and a sidelink secondary synchronization signal (S-SSS).

[0043] Each of the one or more UEs 102 may include one or more transceivers 118, one or more demodulators 114, one or more decoders 108, one or more encoders 150, one or more modulators 154, one or more data buffers 104 and one or more UE operations modules 124. For example, one or more reception and / or transmission paths may be implemented in the UE 102. For convenience, only a single transceiver 118, decoder 108, demodulator 114, encoder 150 and modulator 154 are illustrated in the UE 102, though multiple parallel elements (e.g., transceivers 118, decoders 108, demodulators 114, encoders 150 and modulators 154) may be implemented.

[0044] The transceiver 118 may include one or more receivers (reception units) 120 and one or more transmitters (transmission units) 158. The one or more receivers 120 may receive signals (e.g., downlink channels, downlink signals, sidelink channels, sidelink signals) from the base station 160 or from another UE 102 using one or more antennas 122a-n. For example, the receiver 120 may receive and downconvert signals to produce one or more received signals 116. The one or more received signals 116 maybe provided to a demodulator 114. The one or more transmitters 158 may transmit signals (e.g., uplink channels, uplink signals, sidelink channels, sidelink signals) to the base station 160 or to another UE 102 using one or more antennas 122a-n. For example, the one or more transmitters 158 may upconvert and transmit one or more modulated signals 156.

[0045] The demodulator 114 may demodulate the one or more received signals 116 to produce one or more demodulated signals 112. The one or more demodulated signals 112 may be provided to the decoder 108. The UE 102 may use the decoder 108 to decode signals. The decoder 108 may produce one or more decoded signals 106, 110. For example, a first UE-decoded signal 106 may comprise received payload data, which may be stored in a data buffer 104. A second UE-decoded signal 110 may comprise overhead data and / or control data. For example, the second UE-decoded signal 110 may provide data that may be used by the UE operations module 124 to perform one or more operations.

[0046] As used herein, the term “module” may mean that a particular element or component may be implemented in hardware, software or a combination of hardware and software. However, it should be noted that any element denoted as a “module” herein may alternatively be implemented in hardware. For example, the UE operations module 124 may be implemented in hardware, software or a combination of both.

[0047] In general, the UE operations module 124 may enable the UE 102 to communicate with the one or more base stations 160. For a UE capable of sidelink communication, the UE operations module 124 may enable the UE 102 to communicate with the one or more other UE. The UE operations module 124 may include a UE RRC information configuration module 126. For a UE capable of sidelink communication, the UE operations module 124 may include a UE sidelink (SL) control module (unit) 128. In some implementations, the UE operations module 124 may include physical (PHY) entities, Medium Access Control (MAC) entities, Radio Link Control (RLC) entities, packet data convergence protocol (PDCP) entities, and a Radio Resource Control (RRC) entity. For example, the UE RRC information configuration module 126 may process RRC parameter for random access configurations, initial UL BWP configuration, maximum bandwidth the UE can support, and cell specific PUCCH resource configuration(s).

[0048] For a UE capable of sidelink transmission, the UE RRC information configuration module 126 may process parameters included in the (pre-)configuration(s) related to sidelink communications. The UE RRC information configuration module 126 may include a memory unit to store the (pre-)configuration(s) related to sidelink communications. For example, the UE RRC information configuration module 126 may, based on the parameters, determine a SL BWP, one or more resource pools within the SL BWP in frequency domain and time domain for SL communications. The UE RRC information configuration module 126 may provide information related to SL BWP configuration and resource pool configuration to the UE SL control module 128. The UE SL control module 128 may set the SL BWP configuration and the resource pool configuration.

[0049] The UE SL control module 128 may determine the frequency resources, the time resources, the code resources, and / or numerologies for transmission or reception of the PSCCH, the PSSCH, S-SS / PSBCH and / or the PSFCH. The frequency resources for transmission or reception of the PSCCH, the PSSCH and the PSFCH include information related to assigned sub-channel(s) (or interlace(s)) and RB set(s).

[0050] The UE RRC information configuration module 126 may provide the UE SL control module 128 information regarding whether parameters A, B, C, D, E is configured to the UE for a resource pool or not. The parameters A, B, C, D, E are illustrated below.

[0051] The UE operations module 124 may provide information 148 to the one or more receivers 120. For example, the UE operations module 124 may inform the receiver(s) 120 when or when not to receive transmissions based on the Radio Resource Control (RRC) message (e.g., broadcasted system information, RRC reconfiguration message), MAC control element, SCI (Sidelink Control Information) and / or the DCI (Downlink Control Information). The UE operations module 124 may provide information 148, including the PDCCH monitoring occasions, DCI format size, PSCCH monitoring occasions and SCI format size, to the one or more receivers 120. The UE operation module 124 may inform the receiver(s) 120 when or where to receive / monitor the PDCCH candidate for DCI formats and / or the PSCCH candidate for SCI formats. DCI formats can be used at least for scheduling of SL transmission(s) (PSCCH and / or PSSCH transmission(s)) in one cell and / or for scheduling of PUSCH and / or PDSCH in one cell.

[0052] The UE operations module 124 may provide information 138 to the demodulator 114. For example, the UE operations module 124 may inform the demodulator 114 of a modulation pattern anticipated for transmissions from the base station 160.

[0053] The UE operations module 124 may provide information 136 to the decoder 108. For example, the UE operations module 124 may inform the decoder 108 of an anticipated encoding for transmissions from the base station 160. For example, the UE operations module 124 may inform the decoder 108 of an anticipated PDCCH candidate encoding with which DCI size for transmissions from the base station 160. The UE operations module 124 may inform the decoder 108 of an anticipated PSCCH candidate encoding with which SCI size for transmissions from another UE 102.

[0054] The UE operations module 124 may provide information 142 to the encoder 150. The information 142 may include data to be encoded and / or instructions for encoding. For example, the UE operations module 124 may instruct the encoder 150 to encode transmission data 146 and / or other information 142.

[0055] The encoder 150 may encode transmission data 146 and / or other information 142 provided by the UE operations module 124. For example, encoding the data 146 and / or other information 142 may involve error detection and / or correction coding, mapping data to space, time and / or frequency resources for transmission, multiplexing, etc. The encoder 150 may provide encoded data 152 to the modulator 154.

[0056] The UE operations module 124 may provide information 144 to the modulator 154. For example, the UE operations module 124 may inform the modulator 154 of a modulation type (e.g., constellation mapping) to be used for transmissions to the base station 160. The modulator 154 may modulate the encoded data 152 to provide one or more modulated signals 156 to the one or more transmitters 158.

[0057] The UE operations module 124 may provide information 140 to the one or more transmitters 158. This information 140 may include instructions for the one or more transmitters 158. For example, the UE operations module 124 may instruct the one or more transmitters 158 when to transmit a signal to the base station 160 or another UE 102. The one or more transmitters 158 may upconvert and transmit the modulated signal(s) 156 to one or more base stations 160 or another one or more UEs 102.

[0058] The base station 160 may include one or more transceivers 176, one or more demodulators 172, one or more decoders 166, one or more encoders 109, one or moremodulators 113, one or more data buffers 162 and one or more base station operations modules 182. For example, one or more reception and / or transmission paths may be implemented in a base station 160. For convenience, only a single transceiver 176, decoder 166, demodulator 172, encoder 109 and modulator 113 are illustrated in the base station 160, though multiple parallel elements (e.g., transceivers 176, decoders 166, demodulators 172, encoders 109 and modulators 113) may be implemented.

[0059] The transceiver 176 may include one or more receivers (reception units) 178 and one or more transmitters (transmission units) 117. The one or more receivers 178 may receive signals (e.g., uplink channels, uplink signals) from the UE 102 using one or more antennas 180a-n. For example, the receiver 178 may receive and downconvert signals to produce one or more received signals 174. The one or more received signals 174 may be provided to a demodulator 172. The one or more transmitters 117 may transmit signals (e.g., downlink channels, downlink signals) to the UE 102 using one or more antennas 180a-n. For example, the one or more transmitters 117 may upconvert and transmit one or more modulated signals 115.

[0060] The demodulator 172 may demodulate the one or more received signals 174 to produce one or more demodulated signals 170. The one or more demodulated signals 170 may be provided to the decoder 166. The base station 160 may use the decoder 166 to decode signals. The decoder 166 may produce one or more decoded signals 164, 168. For example, a first base station-decoded signal 164 may comprise received payload data, which may be stored in a data buffer 162. A second base station-decoded signal 168 may comprise overhead data and / or control data. For example, the second base station-decoded signal 168 may provide data (e.g., PUSCH transmission data) that may be used by the base station operations module 182 to perform one or more operations.

[0061] In general, the base station operations module 182 may enable the base station 160 to communicate with the one or more UEs 102. For a base station capable of sidelink communication, the UE operations module 124 may enable the base station 160 to communicate with the one or more UEs 102 capable of sidelink communication. The base station operations module 182 may include a base station RRC information configuration module 194. For a base station capable of sidelink communication, the base station operations module 182 may include a base station sidelink (SL) control module 196 (or a base station SL processing module 196). The base station operationsmodule 182 may include PHY entities, MAC entities, RLC entities, PDCP entities, and an RRC entity.

[0062] For a base station capable of sidelink transmission, the base station SL control module 196 may determine, for respective UE, the time and frequency resources for scheduling PSCCH and PSSCH and input the information to the base station RRC information configuration module 194.

[0063] The base station operations module 182 may provide the benefit of performing PDCCH candidate search and monitoring efficiently. The base station operations module 182 may provide information 190 to the one or more receivers 178. For example, the base station operations module 182 may inform the receiver(s) 178 when or when not to receive transmissions based on the RRC message (e.g., broadcasted system information, RRC reconfiguration message), MAC control element, and / or the DCI (Downlink Control Information).

[0064] The base station operations module 182 may provide information 188 to the demodulator 172. For example, the base station operations module 182 may inform the demodulator 172 of a modulation pattern anticipated for transmissions from the UE(s) 102.

[0065] The base station operations module 182 may provide information 186 to the decoder 166. For example, the base station operations module 182 may inform the decoder 166 of an anticipated encoding for transmissions from the UE(s) 102.

[0066] The base station operations module 182 may provide information 101 to the encoder 109. The information 101 may include data to be encoded and / or instructions for encoding. For example, the base station operations module 182 may instruct the encoder 109 to encode transmission data 105 and / or other information 101.

[0067] In general, the base station operations module 182 may enable the base station 160 to communicate with one or more network nodes (e.g., a NG mobility management function, a NG core UP functions, a mobility management entity (MME), serving gateway (S-GW), gNBs). The base station operations module 182 may also generate a RRC reconfiguration message to be signaled to the UE 102.

[0068] The encoder 109 may encode transmission data 105 and / or other information 101 provided by the base station operations module 182. For example, encoding the data 105 and / or other information 101 may involve error detection and / or correction coding, mapping data to space, time and / or frequency resources fortransmission, multiplexing, etc. The encoder 109 may provide encoded data 111 to the modulator 113. The transmission data 105 may include network data to be relayed to the UE 102.

[0069] The base station operations module 182 may provide information 103 to the modulator 113. This information 103 may include instructions for the modulator 113. For example, the base station operations module 182 may inform the modulator 113 of a modulation type (e.g., constellation mapping) to be used for transmissions to the UE(s) 102. The modulator 113 may modulate the encoded data 111 to provide one or more modulated signals 115 to the one or more transmitters 117.

[0070] The base station operations module 182 may provide information 192 to the one or more transmitters 117. This information 192 may include instructions for the one or more transmitters 117. For example, the base station operations module 182 may instruct the one or more transmitters 117 when to (or when not to) transmit a signal to the UE(s) 102. The base station operations module 182 may provide information 192, including the PDCCH monitoring occasions and DCI format size, to the one or more transmitters 117. The base station operation module 182 may inform the transmitter(s) 117 when or where to transmit the PDCCH candidate for DCI formats with which DCI size. The one or more transmitters 117 may upconvert and transmit the modulated signal(s) 115 to one or more UEs 102.

[0071] It should be noted that one or more of the elements or parts thereof included in the base station(s) 160 and UE(s) 102 may be implemented in hardware. For example, one or more of these elements or parts thereof may be implemented as a chip, circuitry or hardware components, etc. It should also be noted that one or more of the functions or methods described herein may be implemented in and / or performed using hardware. For example, one or more of the methods described herein may be implemented in and / or realized using a chipset, an application-specific integrated circuit (ASIC), a large-scale integrated circuit (LSI) or integrated circuit, etc.

[0072] A base station may generate a RRC message including the one or more RRC parameters and may transmit the RRC message to a UE. A UE may receive, from a base station, a RRC message including one or more RRC parameters. In the present disclosure, the terms ‘RRC parameter(s)’, ‘RRC information element(s)’, ‘higher layer parameter(s)’ can be used interchangeably. In the present disclosure, higher layer mayreefer to a layer upper than the physical layer (i.e., Layer 1), for example, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and / or application layer.

[0073] A RRC parameter may further include one or more RRC parameter(s). In the present disclosure, a RRC message may include system information, a RRC message may include one or more RRC parameters. A RRC message may be sent on a broadcast control channel (BCCH) logical channel, a common control channel (CCCH) logical channel or a dedicated control channel (DCCH) logical channel.

[0074] In the present disclosure, a description “a UE is configured with or is provided a parameter” also implies the description “the UE may receive, from the base station, an RRC message (or information) which includes the parameter”. Likewise, the description “a base station configures the UE with or provides the UE the parameter” also implies the description “the base station may transmit, to the UE, an RRC message (or information) which includes the parameter”.

[0075] Figure 2 is a diagram illustrating one example of a resource grid 200.

[0076] For each numerology (i.e., for each SCS w) and carrier, a resource grid of subcarriers and e OFDM symbols is defined, starting atcommon resource blockindicated by higher layer signaling. There is one set of resource grids per transmission direction (uplink or downlink) with the subscript x set to DL and UL for downlink and uplink, respectively. There is one resource grid for a given antenna port p, subcarrier spacing configuration p, and the transmission direction (downlink or uplink). When there is no risk for confusion, the subscript x may be dropped.

[0077] In the Figure 2, the resource gird 200 includes the(202) subcarriers in the frequency domain and includese (204) symbols in the time domain. In the Figure 2, as an example for illustration, the subcarrier spacing configuration p is set to 0. That is, in the Figure 2, the number of consecutive OFDM symbols (204) per subframe is equal to 14.

[0078] The carrier bandwidthe'^for subcarrier spacingconfiguration p is given by the higher-layer (RRC) parameter carrierBandwidth in the SCS-SpecificCarrier IE. The starting positionfor subcarrier spacing configuration p is given by the higher-layer parameter offsetToCarrier in the SCS- SpecificCarrier IE. The frequency location of a subcarrier refers to the center frequency of that subcarrier.

[0079] In the Figure 2, for example, a value of offset is provided by the higher-layer parameter offsetToCarrier. That is, k= 12 X offset is the lowest usable subcarrier on this carrier.

[0080] Each element in the resource grid for antenna port p and subcarrier spacing configuration p is called a resource element and is uniquely identified by (k, l)p^ where k is the index in the frequency domain and I refers to the symbols position in the time domain relative to same reference point. The resource element consists of one subcarrier during one OFDM symbol.

[0081] A resource block is defined as ASCRB=12 consecutive subcarriers in the frequency domain. As shown in the Figure 2, a resource block 206 includes 12 consecutive subcarriers in the frequency domain. Resource block can be classified as common resource block (CRB) and physical resource block (PRB).

[0082] Common resource blocks are numbered from 0 and upwards in the frequency domain for subcarrier spacing configuration The center of subcarrier 0 of common resource block with index 0 (i.e. CRB0) for subcarrier spacing configuration p coincides with point A. The relation between the common resource block numbernCRB ’nthe frequency domain and resource element (k, Z) for subcarrier spacing configuration p is given by Formula (1) ncRpl=floor(k / NScRB') where k is defined relative to the point A such that / c=0 corresponds to the subcarrier centered around the point A. The function floor(A) hereinafter is floor operation to output a maximum integer not larger than the A.

[0083] Point A refers to as a common reference point. Point A coincides with subcarrier 0 (i.e., A=0) of a CRB 0 for all subcarrier spacing. Point A can be obtained from a RRC parameter offsetToPointA or a RRC parameter absoluteFrequencyPointA. The RRC parameter offsetToPointA is used for a PCell downlink and represents the frequency offset between point A and the lowest subcarrier of the lowest resource block, which has the subcarrier spacing provided by a higher-layer parameter subCarrierSpacingCommon and overlaps with the SS / PBCH block used by the UE for initial cell selection, expressed in units of resource blocks assuming 15 kHz subcarrier spacing for frequency range (FR) 1 and 60 kHz subcarrier spacing for frequency range (FR2). FR1 corresponds to a frequency range between 410MHz and 7125MHz. FR2 corresponds to a frequency range between 24250MHz and 52600MHz. The RRCparameter absoluteFrequencyPointA is used for all cased other than the PCell case and represents the frequency-location of point A expressed as in ARFCN. The frequency location of point A can be the lowest subcarrier of the carrier bandwidth ( or the actual carrier). Additionally, point A may be located outside the carrier bandwidth ( or the actual carrier).

[0084] As above mentioned, the information element (IE) SCS-SpecificCarrier provides parameters determining the location and width of the carrier bandwidth or the actual carrier. That is, a carrier (or a carrier bandwidth, or an actual carrier) is determined (identified, or defined) at least by a RRC parameter offsetToCarrier , a RRC parameter subcarrierSpacing, and a RRC parameter carrierBandwidth in the SCS- SpecificCarrier IE.

[0085] The subcarrierSpacing indicates (or defines) a subcarrier spacing of the carrier. The offsetToCarrier indicates an offset in frequency domain between point A and a lowest usable subcarrier on this carrier in number of resource blocks (e.g. CRBs) using the subcarrier spacing defined for the carrier. The carrierBandwidth indicates width of this carrier in number of resource blocks (e.g., CRBs or PRBs) using the subcarrier spacing defined for the carrier. A carrier includes at most 275 resource blocks.

[0086] Physical resource blocks for subcarrier spacing configuration p are defined within a bandwidth part and numbered form 0 tohere i is the number of the bandwidth part. The relation between the physical resource block nppf in bandwidth part (BWP) i and the common resource blockis given by Formula (2)whereis the common resource block where bandwidth part i starts relative to common resource block 0 (CRB0). When there is no risk for confusion the index p may be dropped.

[0087] A BWP is a subset of contiguous common resource block for a given subcarrier spacing configuration p on a given carrier. To be specific, a BWP can be identified (or defined) at least by a subcarrier spacing p indicated by the RRC parameter subcarrierSpacing, a cyclic prefix determined by the RRC parameter cyclicPreflx, a frequency domain location, a bandwidth, an BWP index indicated by bwp-td and so on. The locationAndBandwidth can be used to indicate the frequency domain location and bandwidth of a BWP. The value indicated by the locationAndBandwidth is interpreted as resource indicator value (RIV) corresponding to an offset (a starting resource block) 7?5start and a length ZRB in terms of contiguously resource blocks. The offset RB^t is aμumber of CRBs between the lowest CRB of the carrier and the lowest CRB of the BWP. Theis given as Formula (3) NBWP,tstart' ■" =Ocamer+7?5start. The value of Ocarrier is provided by offsetTocarrier for the corresponding subcarrier spacing configuration jj..

[0088] A UE 102 configured to operate in B WPs of a serving cell, is configured by higher layers for the serving cell a set of at most four BWPs in the downlink for reception. At a given time, a single downlink BWP is active. The bases station 160 may not transmit, to the UE 102, PDSCH and / or PDCCH outside the active downlink BWP. A UE 102 configured to operate in BWPs of a serving cell, is configured by higher layers for the serving cell a set of at most four BWPs for transmission. At a given time, a single uplink BWP is active. The UE 102 may not transmit to the base station 160, PUSCH or PUCCH outside the active BWP. The specific signaling (higher layers signaling) for BWP configurations are described later.

[0089] A UE 102, configured to operate in a SL BWP, is configured or preconfigured by higher layers for the serving cell or by a pre-configuration a SL BWP for sidelink reception and / or transmission. At a given time, a single SL BWP is active. The UE 102 may not transmit, to another UE 102, sidelink channel (PSCCH, PSCCH, and / or PSFCH) outside the active SL BWP.

[0090] Figure 3 is a diagram illustrating one example 300 of common resource block grid, carrier configuration and BWP configuration by a UE 102 and a base station 160.

[0091] Point A 301 is the lowest subcarrier of a CRB0 for all subcarrier spacing configurations. The CRB grid 302 and the CRB grid 312 are corresponding to two different subcarrier spacing configurations. The CRB grid 302 is for subcarrier spacing configuration μ =0 (i.e., the subcarrier spacing with 15kHz). The CRB grid 312 is for subcarrier spacing configuration μ =1 (i.e., the subcarrier spacing with 30kHz).

[0092] One or more carriers are determined by respective SCS-SpecificCarrier EEs, respectively. In the Figure 3, the carrier 304 uses the subcarrier spacing configuration p=0. And the carrier 314 uses the subcarrier spacing configuration μ=1. The starting positionof the carrier 304 is given based on the value of an offset 303 (i.e. Ocarrier) indicated by an offsetToCarrier in an SCS-SpecificCarrier IE. As shown in the Figure 3, for example, the offsetToCarrier indicates the value of the offset 303 as Ocarrier =3. That is, the starting positionof the carrier 304 corresponds to the CRB3 ofthe CRB grid 302 for subcarrier spacing configuration p-Q. In the meantime, the starting position Agri / tort,Aof the carrier 314 is given based on the value of an offset 313 (i.e. Ocarrier) indicated by an offsetToCarrier in another SCS-SpecificCarrier IE. For example, the offsetToCarrier indicates the value of the offset 313 as Orame / =1. That is, the starting position NeC'artJJof the carrier 314 corresponds to the CRB1 of the CRB grid 312 for subcarrier spacing configuration ^=1. A carrier using different subcarrier spacing configurations can occupy different frequency ranges.

[0093] As above-mentioned, a BWP is for a given subcarrier spacing configuration / / . One or more BWPs can be configured for a same subcarrier spacing configuration p. For example, in the Figure 3, the BWP 306 is identified at least by the p=0, a frequency domain location, a bandwidth (ZRB), and an BWP index (index A). The first PRB (i.e. PRBO) of a BWP is determined at least by the subcarrier spacing of the BWP, an offset derived by the locationAndBandwidth and an offset indicated by the offsetToCarrier corresponding to the subcarrier spacing of the BWP. An offset 305 (RRstart) is derived as 1 by the locationAndBandwidth. According to the Formulas (2) and (3), the PRBO of BWP 306 corresponds to CRB 4 of the CRB grid 302, and the PRB1 of BWP 306 corresponds to CRB 5 of the CRB grid 302, and so on.

[0094] Additionally, in the Figure 3, the BWP 308 is identified at least by thea frequency domain location, a bandwidth (ERB), and an BWP index (index B). For example, an offset 307 (RRstart) is derived as 6 by the locationAndBandwidth. According to the Formulas (2) and (3), the PRBO of BWP 308 corresponds to CRB 9 of the CRB grid 302, and the PRB1 of BWP 308 corresponds to CRB 10 of the CRB grid 302, and so on.

[0095] Additionally, in the Figure 3, the BWP 316 is identified at least by the ^=7, a frequency domain location, a bandwidth (ZRB), and an BWP index (index C). For example, an offset 315 (Restart) is derived as 1 by the locationAndBandwidth. According to the Formulas (2) and (3), the PRBO of BWP 316 corresponds to CRB 2 of the CRB grid 312, and the PRB1 of BWP 316 corresponds to CRB 3 of the CRB grid 312, and so on.

[0096] In the present disclosure, a BWP illustrated in the Figure 3 may refer to a DL BWP, a UL BWP, or a sidelink BWP.

[0097] As shown in the Figure 3, a carrier with the defined subcarrier spacing locate in a corresponding CRB grid with the same subcarrier spacing. A BWP with the definedsubcarrier spacing locate in a corresponding CRB grid with the same subcarrier spacing as well.

[0098] A base station may transmit a RRC message including one or more RRC parameters related to BWP configuration to a UE. A UE may receive the RRC message including one or more RRC parameters related to BWP configuration from a base station. For each cell, the base station may configure at least an initial DL BWP, one initial uplink bandwidth parts (initial UL BWP) and one sidelink BWP to the UE. Furthermore, the base station may configure additional UL and DL BWPs to the UE for a cell.

[0099] SIB1, which is a cell-specific system information block (SystemlnformationBlock, SIB), may contain information relevant when evaluating if a UE is allowed to access a cell and define the scheduling of other system information. SIB1 may also contain radio resource configuration information that is common for all UEs, and barring information applied to the unified access control. The RRC parameter ServingCellConfigCommon is used to configure cell specific parameters of a UE's serving cell. The RRC parameter ServingCellConfig is used to configure (add or modify) the UE with a serving cell, which may be the SpCell or an SCell of an MCG or SCG. The RRC parameter ServingCellConfig herein are mostly UE specific but partly also cell specific.

[0100] The base station may configure the UE with a RRC parameter BWP- Downlink and a RRC parameter BWP -Uplink. The RRC parameter BWP -Downlink can be used to configure an additional DL BWP. The RRC parameter BWP-Uplink can be used to configure an additional UL BWP. The base station may transmit the BWP- Downlink and the BWP-Uplink which may be included in RRC parameter ServingCellConfig to the UE.

[0101] The UE may be configured by the based station, at least one initial BWP and up to 4 additional BWP(s). One of the initial BWP and the configured additional BWP(s) may be activated as an active BWP. The UE may monitor DCI format, and / or receive PDSCH in the active DL BWP. The UE may not monitor DCI format, and / or receive PDSCH in a DL BWP other than the active DL BWP. The UE may transmit PUSCH and / or PUCCH in the active UL BWP. The UE may not transmit PUSCH and / or PUCCH in a BWP other than the active UL BWP.

[0102] As above-mentioned, a UE may monitor DCI format in the active DL BWP. To be more specific, a UE may monitor a set of PDCCH candidates in one or more CORESETs on the active DL BWP on each activated serving cell configured with PDCCH monitoring according to corresponding search space set where monitoring implies decoding each PDCCH candidate according to the monitored DCI formats.

[0103] A set of PDCCH candidates for a UE to monitor is defined in terms of PDCCH search space sets. A search space set can be a CSS set or a USS set. A UE may monitor a set of PDCCH candidates in one or more of the search space sets.

[0104] Figure 4 is a diagram illustrating one 400 example of CORESET configuration in a BWP by a UE 102 and a base station 160.

[0105] Figure 4 illustrates that a UE 102 is configured with three CORESETs for receiving PDCCH transmission in two BWPs. In the Figure 4, 401 represent point A. 402 is an offset in frequency domain between point A 401 and a lowest usable subcarrier on the carrier 403 in number of CRBs, and the offset 402 is given by the offsetToCarrier in the SCS-SpecificCarrier IE. The BWP 405 with index A and the carrier 403 are for a same subcarrier spacing configuration p. The offset 404 between the lowest CRB of the carrier and the lowest CRB of the BWP in number of RBs is given by the locationAndBandwidth included in the BWP configuration for BWP A. The BWP 407 with index B and the carrier 403 are for a same subcarrier spacing configuration p. The offset 406 between the lowest CRB of the carrier and the lowest CRB of the BWP in number of RBs is given by the locationAndBandwidth included in the BWP configuration for BWP B.

[0106] For the BWP 405, two CORESETs are configured. As above-mentioned, a RRC parameter frequencyDomainResource in respective CORESET configuration indicates the frequency domain resource for respective CORESET. In the frequency domain, a CORESET is defined in multiples of RB groups and each RB group consists of 6 RBs. For example, in the Figure 4, the RRC parameter frequencyDomainResource provides a bit string with a fixed size (e.g., 45 bits) as like ‘ 11010000...000000’ for CORESET#1. That is, the first RB group, the second RB group, and the fourth RB group belong to the frequency domain resource of the CORESET#! . Additionally, the RRC parameter frequencyDomainResource provides a bit string with a fixed size (e.g., 45 bits) as like ‘00101110...000000’ for CORESET#2. That is, the third RB group, thefifth RB group, the sixth RB group and the seventh RB group belong to the frequency domain resource of the CORESET#2.

[0107] For the BWP 407, one CORESET is configured. As above-mentioned, a RRC parameter frequencyDomainResource in the CORESET configuration indicates the frequency domain resource for the CORESET #3. In the frequency domain, a CORESET is defined in multiples of RB groups and each RB group consists of 6 RBs. For example, in the Figure 4, the RRC parameter frequencyDomainResource provides a bit string with a fixed size (e.g., 45 bits) as like ‘ 11010000. ..000000’ for CORESET#3. That is, the first RB group, the second RB group, and the fourth RB group belong to the frequency domain resource of the CORESET#3. Although the bit string configured for CORESET&3 is same as that for CORESET#!, the first RB group of the BWP B is different from that of the BWP A in the carrier. Therefore, the frequency domain resource of the CORESET&3 in the carrier is different from that of the CORESET#! as well.

[0108] For the communication system, spectrum is divided into licensed spectrum and unlicensed spectrum. The NR technologies have been developed in the licensed spectrum and in the unlicensed spectrum. The operation in unlicensed spectrum, used as a complementary solution, can increase the throughput of the overall wireless communication system. However, operation in unlicensed spectrum is subject to regulatory limitations and restrictions. For example, the European Telecommunications Standards Institute (ETSI) has defined regulations for operation over the unlicensed spectrum. For example, the occupied channel bandwidth (OCB), which is defined as a bandwidth containing 99% of the signal power, should be larger than a percentage of the nominal channel bandwidth (NCB). For example, according to the ETSI regulations, the OCB should be between 70% and 100% of the NCB for 5GHz band.

[0109] An unlicensed band (or a carrier, or a subband) would be divided into one or multiple non-overlapping channels of 20MHz bandwidth in the frequency domain. For a (nominal) channel bandwidth of 20MHz, one transmission should occupy a channel bandwidth larger than what the regulation on OCB requires, for example, one transmission should be larger than 80% of the channel bandwidth of 20MHz to meet the OCB requirement. To meet the OCB requirement, the design of interlaced transmission had been introduced where each interlace transmission within a channel bandwidth can occupy a channel bandwidth being larger than what the OCB requires.

[0110] The unlicensed band (unlicensed spectrum) may be or may be not configured with operation with shared spectrum channel access. Likewise, the licensed band (licensed spectrum) may be or may be not configured with operation with shared spectrum channel access. In the present disclosure, the unlicensed band (the unlicensed spectrum) configured with operation with shared spectrum channel access can be termed the unlicensed band A (the unlicensed spectrum A). The unlicensed band (unlicensed spectrum) not configured with operation with shared spectrum channel access can be termed the unlicensed band B (the unlicensed spectrum B). The licensed band (the licensed spectrum) configured with operation with shared spectrum channel access can be termed the licensed band C (the licensed spectrum C). The licensed band (licensed spectrum) not configured with operation with shared spectrum channel access can be termed the licensed band D (the licensed spectrum D).

[0111] Interlaced transmission had been introduced to ensure the compliance with the regulations on OCB and NCB requirements. Specifically, the interlaced transmission is designed such that each interlace can occupy the channel bandwidth where the occupied channel bandwidth can fulfill the requirement of the OCB.

[0112] An interlace includes a set of resource blocks that are spread out across the bandwidth of a carrier in the frequency domain. A number of interlaces M is subject to the value of a SCS. That is, the number of interlaces M may be predefined according to a specific SCS. For example, if the SCS is equal to 15kHz, the number of resource block interlaces M is correspondingly equal to 10. If the SCS is equal to 30kHz, the number of resource block interlaces Mis correspondingly equal to 5.

[0113] Figure 5 is a diagram illustrating one example 500 of interlaced transmission and reception in a BWP.

[0114] In the Figure 5, each block in the frequency domain refers to a common resource block. In the Figure 5, the subcarrier spacing is configured as 30kHz and the number of resource block interlaces Mare 5. Then the interlaces are indexed from 0 to M-l. That is, an interlace m, where m = 0, 1, ..., M-l, consists of a plurality of common resource blocks with indexes {m, M+m, 2M+m, 3M+m, ...}. For example, in the Figure 5, the interlace m=0 consists of common resource blocks with indexes {0, 5, 10, 15, ...}, the interlace w=l consists of common resource blocks with indexes { 1, 6, 11, 16, .. .}, and so on.

[0115] In the frequency domain, a BWP 501 is determined as illustrated in Figure 3. An interlaced resource block in the BWP is denoted as nfRB mwhere theis indexed from 0, 1, in the BWP. The relation between the interlace resource blockinterlace m and the common resource blockis given byresourceblock where the BWP starts relative to common resource block 0 (i.e., a common resource block with index 0). In the Figure 5, the BWP 501 starts in a CRB with index 4 relative to the CRB with index 0.

[0116] At least for NR-U operation in, for example, 5GHz spectrum, a BWP may have a bandwidth of multiple of 20MHz. A sub-band may comprise 20MHz or a multiple of 20MHz bandwidth. A sub-band may also be referred to as a sub-channel, or a channel access bandwidth (e.g., a channel of 20MHz). Then a BWP may include one or more sub-bands in the frequency domain. A sub-band consists of multiple nonoverlapping RBs. The number of resource blocks within a sub-band may depend on the SCS of the BWP. For example, the sub-band size for SCS=15kHz may be equal to 108 for a 40MHz BWP, and the sub-band size for SCS=30kHz may be equal to 53 for a 40MHz BWP. That is, a sub-band is an RB set of non-overlapping and contiguous (common) resource blocks. And a sub-band can be defined by a starting common RB and an ending common RB in the frequency domain. Hereinafter, an RB set is used to refer to a sub-band. In other words, an RB set consists of non-overlapping resource blocks and can be defined by a starting common RB and an ending common RB.

[0117] As in the Figure 5, the BWP 501 includes two RB sets, i.e., a RB set 502 and a RB set 503. The RB sets within a BWP can be indexed from 0 in an increase order along with the frequency. According to higher layer (RRC) configurations, there may be a gap 504 between two consecutive RB sets. The gap in unit of resource block can be indicated by the higher layer configurations. Additionally or alternatively, there may be no gap between two RB sets. In other words, there may be a separation of zero, one, or more RBs between two contiguous RB sets within the BWP in the frequency domain.

[0118] In the Figure 5, in the frequency domain, a interlace whose RBs have a lowest CRB index within the first RB set is the interlace m = 4, while the interlace whose RBs have a lowest CRB index within the second RB set is the m = 0.

[0119] In order to ensure a fair co-existence with another NR-U node and / or another radio access technology (RAT) node such as wireless LAN node, the base station 160 and / or the UE 102 may have to perform Listen Before Talk (LBT) procedure before their transmissions. LBT procedure is also referred to as Channel Access procedure. The base station 160 and / or the UE 102 may perform the channel access procedure to determine if there is the presence of other transmission in a channel before their transmission. There may be several types of Channel Access (CA) procedures. For example, Cat-1 LBT is a channel access procedure without channel sensing. Cat-2 LBT is a channel access procedure with one shot channel sensing. Cat-2 LBT may also be referred to as Type-2 channel access procedure. Cat-1 and Cat-2 LBTs may be allowed only inside COT. Cat-3 LBT is a channel access procedure with random backoff with a fixed contention window (CW) size. Cat-4 LBT is a channel access procedure with random backoff with an adaptive CW size. Cat-4 LBT may also be referred to as Type- 1 channel access procedure.

[0120] In a BWP, before a gNB and / or a UE attempt to transmit a signal, the gNB and / or the UE may first perform channel sensing in each RB set to check whether a channel (or one or more RB sets within the BWP allocated for transmission) is available or not for transmission. If the channel or the allocated RB set(s) is sensed to be considered to be idle (i.e., the channel is available for transmission or the gNB and / or the UE gets a channel access successfully), the gNB and / or the UE may transmit on the channel or on the allocated RB set(s). On the other hand, if the channel or the allocated RB set(s) is sensed to be considered to be busy (i.e., the channel is not available or the gNB and / or the UE does not get a channel access successfully), the gNB and / or the UE may not transmit on the channel or on the allocated RB set(s).

[0121] Vehicle-to-everything (V2X) communication technologies have been developed by 3 GPP for the automotive industry. V2X refers to a communication technology through which a vehicle exchanges information with another vehicle, a pedestrian, an object having an infrastructure, and so on. The V2X is divided into 4 types, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to- network (V2N), and vehicle-to-pedestrian (V2P). Therefore, the V2X communication is different from the communication between the UEs and gNBs. The V2X communication enables the communication between the UEs, which is also called as sidelink. That is, sidelink communication supports UE-to-UE direct communication viaa PC5 interface. In other words, sidelink communication is directly performed or communicated between one transmitting UE and one or more receiving UEs.

[0122] Sidelink communication consists of unicast, groupcast and broadcast. The unicast may refer to a communication between two UEs, i.e., one transmitting UE and one receiving UE. The groupcast and / or the broadcast may refer to a communication between one transmitting UE and multiple receiving UEs.

[0123] Currently NR Sidelink communication supports two sidelink resource allocation modes, mode 1 and mode 2. The difference between the sidelink resource allocation mode 1 and the sidelink resource allocation mode 2 lies in which determine the resource to be used for the sidelink communication.

[0124] In mode 1, the sidelink resource allocation is provided or determined by the base station and / or the network. That is, for mode 1, the base station may manage the resource allocation for the UEs. For example, a base station may allocate the resources for sidelink communication to an in-coverage UE. In sidelink resource allocation mode 1 , dynamic grant, configured grant type 1 and configured grant type 2 are supported for PSSCH and PSCCH transmission. In sidelink resource allocation mode 1, for sidelink dynamic grant, the PSSCH transmission is scheduled by a DCI format 3_0. For sidelink configured grant type 1, the configured grant is provided (activated) or released (deactivated) by RRC signaling. For sidelink configured grant type 2, the configured grant is provided or released by PDCCH with the DCI format 3_0.

[0125] In mode 2, the sidelink resource allocation is determined by a TX UE itself. The UE may decide the sidelink transmission resources in a resource pool. The UE may carry out the resource allocation without involvement of the base station. These UEs may autonomously determine to select resources for sidelink communication based on a sensing-based procedure.

[0126] In mode 1, the DCI format 3_0 is used by the base station for scheduling of NR PSCCH and NR PSSCH in one cell. The base station may determine the scheduling information of NR PSCCH and NR PSSCH and provide the scheduling information to an in-coverage UE. The scheduling information may at least include a Resource pool index field, a time gap field, a HARQ process number field, a new data indicator field, a Lowest index of the subchannel allocation to the initial transmission field, SCI format 1-A fields, and so on. The Resource pool index field is used to indicate an index of a resource pool for which the sidelink transmission is scheduled and the SCI format 1-Afields here refer to the frequency resource assignment field and the time resource assignment field. That is, in mode 1 , the base station may determine the time and frequency resource assignment for scheduling of sidelink transmission and then generate the corresponding fields of the scheduling information in the DCI format 3_0. A TX UE (an in-coverage UE) that received the DCI format 3_0 may transmit the PSCCH with SCI format 1-A and the PSSCH in the resource assigned by the base station based on the scheduling information in the DCI format 3_0. Moreover, the SCI format 1 -A transmitted by the TX UE includes the frequency resource assignment field and the time resource assignment field which are as same as those included in the DCI format 3_0. A RX UE (an out-coverage UE and / or an in-coverage UE) that received the PSCCH with the SCI format 1-A can receive the PSSCH in the resource assigned by the base station.

[0127] In mode 2, a TX UE may autonomously determine to select resources for sidelink communication and generate the fields in SCI format 1-A to notify an RX UE of the time and frequency resource assignment. The RX UE that received the PSCCH with the SCI format 1 -A can receive the PSSCH in the resource assigned by the TX UE.

[0128] Sidelink communication supports physical channels such as Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Feedback Channel (PSFCH), and Physical Sidelink Broadcast Channel (PSBCH).

[0129] The PSCCH is used for transmitting / receiving sidelink control information (e.g., the lst-stage SCI). For example, the PSCCH indicates resource and other transmission parameters used by a UE for PSSCH reception. PSCCH transmission is associated with a DM-RS. For PSCCH, QPSK is supported.

[0130] The PSSCH is used for transmitting / receiving sidelink control information (e.g., the 2nd-stage SCI), transport block(s) of data, and channel state information (CSI). The sidelink control information herein may include information, for example, for HARQ for HARQ procedures and CSI feedback triggers, etc. At least 6 OFDM symbols within a slot are used for PSSCH transmission. PSSCH transmission is associated with a DM-RS and may be associated with a PT-RS. For PSSCH, QPSK, 16QAM, 64QAM and 256QAM are supported.

[0131] Each PSSCH transmission is associated with an PSCCH transmission. A PSCCH transmission carries the 1ststage of the SCI where the 1ststage of the SCI mayschedule one or more resources for one or more PSSCH transmissions. That is, the one or more PSSCH transmissions are associated with the PSCCH transmission. In other words, the PSCCH transmission (or the 1ststage of the SCI) may be associated with one or more PSSCH transmissions.

[0132] PSFCH is used for carrying HARQ feedback over the sidelink from a UE which is an intended recipient of a PSSCH transmission to the UE which performed the PSSCH transmission. PSFCH sequence is transmitted in one PRB repeated over two OFDM symbols near the end of the sidelink resource in a slot.

[0133] The PSBCH is used for transmitting broadcast information. PSBCH occupies 9 and 7 symbols for normal and extended CP cases respectively, including the associated DM-RS.

[0134] Sidelink communication supports physical signals such as demodulation reference signal (DM-RS), phase-tracking reference signal (PT-RS), channel-state information reference signal (CSI-RS), sidelink synchronization signals.

[0135] The DMRS(s) are associated with PSCCH, PSSCH and / or PSBCH. A transmitting UE may transmit the DMRS within the associated sidelink physical channel. A receiving UE may use the DMRS to estimate and / or decode the associated sidelink physical channel.

[0136] The PT-RS is used to mitigate the effect of phase noise. A transmitting UE may transmit the PT-RS within the PSSCH transmission. The receiving UE may receive the PT-RS and use the PT-RS to mitigate the effect of phase noise.

[0137] The CSI-RS is used for measuring channel state information. A transmitting UE may transmit sidelink CSI-RS within a unicast PSSCH transmission. A receiving UE may measure the channel state information by using the CSI-RS and transmit a CSI report based on the measurement to the transmitting UE.

[0138] The Sidelink synchronization signal consists of sidelink primary and sidelink secondary synchronization signals (S-PSS, S-SSS), each occupying 2 symbols and 127 subcarriers. The sidelink synchronization signals are transmitted together with the PSBCH in a slot. Specifically, reception occasions of a PSBCH, S-PSS, and S-SSS are in consecutive symbols in a slot and form a S-SS / PSBCH block. For a SL-BWP, the S-SS / PSBCH block has a same SCS as the PSCCH, the PSSCH, and / or the PSFCH.

[0139] In various implementations of the present disclosure, a UE may be provided NR sidelink communication (pre-)configuration(s). For simplicity,(pre-)configuration(s) hereinafter refer to the NR sidelink communication (pre-)configuration(s). (Pre-)configuration(s) in the present disclosure may include configuration(s) received by system information (e.g., SIB 12) from a base station, configuration(s) received by dedicated RRC signaling (e.g., RRC configuration / parameters / message) from a base station, and / or configuration(s) preconfigured in the UE (i.e., pre-configuration). Regarding the pre-configuration, a memory unit of the UE may store the pre-configuration in advance.

[0140] In various examples or implementations of the present disclosure, (pre-)configuration(s) may include configuration(s) of one or more sidelink BWPs for sidelink communication. That is, a UE may receive the configuration(s) of the one or more BWPs included in system information, in dedicated RRC signaling, and / or in a pre-configuration. In the present disclosure, a UE may be provided by the (pre-)configuration(s) a BWP for sidelink transmissions.

[0141] In various examples or implementations of the present disclosure, a SL BWP configuration may include configuration(s) of one or more resource pools for sidelink communication. That is, the configuration(s) of the one or more resource pools (the configuration(s) related to the one or more resource pools) may be received in system information, received in dedicated RRC signaling, and / or preconfigured in a preconfiguration. According to the configuration(s), a resource pool may be indicated to be used either for sidelink communication reception or for sidelink communication transmission. Additionally or alternatively, a resource pool may be indicated to be used for both sidelink communication reception and sidelink communication transmission. Each resource pool is associated with either the sidelink resource allocation Mode 1 or the sidelink resource allocation Mode 2.

[0142] Figure 6 is a diagram illustrating one example 600 of a SL BWP and a resource pool within the SL BWP.

[0143] A UE 102 is provided by a parameter SL-BWP-Conflg a BWP (a SL BWP) for sidelink transmission with numerology and resource grid. The determination of a SL BWP 601 is similar as how to determine a BWP specified in the Figure 3.

[0144] In the Figure 6, each block in the time domain represents a slot. One resource pool is configured within the SL BWP 601. The resource pool can be for transmission of PSSCH, PSCCH and / or PSFCH, and / or for reception of PSSCH, PSCCH and / orPSFCH. The first RB of the resource pool relative to the first RB of SL BWP, 602, may be indicated by a parameter included in the (pre-)configurations.

[0145] Not all the slots within the SL BWP may be assigned to a resource pool within the SL BWP. That is, not all the slots may belong to a resource pool. A slot assigned to a resource pool (or a slot belongs to a resource pool) can be also referred to a slot available for the resource pool. On the contrary, a slot not assigned to a resource pool (or a slot does not belong to a resource pool) can be also referred to a slot unavailable for the resource pool. Therefore, a resource pool may consist of a plurality (set) of non-contiguous slots in the time domain. In a SL BWP, different resource pools may be assigned with different sets of slots. The UE may determine the set of slots assigned to a resource pool according to the (pre-)configurations. A transmitting UE may transmit one or more physical SL channels or one or more SL signals in one or more resource pools within a SL BWP, while a receiving UE may receive one or more physical SL channels or one or more SL signals in one or more resource pools within a SL BWP.

[0146] In the Figure 6, slot#0 refers to a first slot of a radio frame corresponding to SFN 0 of the serving cell or DFN 0. As illustrated in the Figure 6, a set of slots with indexes #4, #5, #7 and #10 belong to the resource pool. The slots in the set for a resource pool are re-indexed such that the logical slot indexes are successive from 0 to T’max -1 where the T’max is the number of the slot in the set. For example, in the Figure 6, the four slots in the set can be re-indexed as slots with logical slot indexes 0, 1, 2, and 3. The slots available for a resource pool may be provided or indicated by a parameter sl- TimeResource and may occur with a periodicity of 10240 ms.

[0147] Sidelink control information is split into two stages, i.e., lst-stage SCI and 2nd-stage SCI. Specifically, SCI carries on PSCCH is the 1st-stage SCI, which transports sidelink scheduling information. That is, the 1st- stage SCI is sent on PSCCH. The SCI carries on PSSCH is the 2nd-stage SCI, which transports sidelink scheduling information, and / or inter-UE coordination related information. That is, the 2nd- stage SCI is send on PSSCH.

[0148] The fields of the l3t-stage SCI formats (e.g., the SCI format 1-A) are mapped to the information bits of the 1st- stage SCI. The SCI format 1-A is used for the scheduling of PSSCH and 2nd- stage SCI on PSSCH.

[0149] The SCI format 1-A may include the following fields, e.g., Priority, Frequency resource assignment, Time resource assignment, Resource reservation period, DMRS pattern, 2nd-stage SCI format, Beta_offset indicator, Number of DMRS port, Modulation and coding scheme, Additional MCS table indicator, PSFCH overhead indication, Reserved, Conflict information receiver flag. As above-mentioned, in Mode I, the UE may obtain the time resource assignment field and the frequency resource assignment field from DCI format 3_0 and include them in SCI format 1-A. In mode 2, the UE may determine the resource allocation for sidelink transmission and generate the time resource assignment field and the frequency resource assignment field in SCI format 1-A.

[0150] The fields defined in each of the 2nd- stage SCI formats (e.g., the SCI format 2-A, SCI format 2-B, SCI format 2-C) are mapped to the information bits of the 2nd- stage SCI. The SCI format 2-A is used for the decoding of PSSCH, with HARQ operation when HARQ-ACK information includes ACK or NACK, when HARQ-ACK information includes only NACK, or when there is no feedback of HARQ-ACK information. The SCI format 2-B is used for the decoding of PSSCH, with HARQ operation when HARQ-ACK information includes only NACK, or when there is no feedback of HARQ-ACK information. The SCI format 2-C is used for the decoding of PSSCH and providing inter-UE coordination information or requesting inter-UE coordination information.

[0151] In NR Releases 16 / 17, sidelink communication was developed to operate in licensed spectrum. In NR Release 18, to further support commercial use cases with increased sidelink data rate, sidelink communication over unlicensed spectrum is under discussion. As above-mentioned, operation over unlicensed spectrum should fulfill different regulatory limitations and restrictions, e.g., OCB / NCB requirements. Interlaced transmission should be introduced for sidelink communication over unlicensed spectrum such that the regulatory requirement can be fulfilled. Hereinafter, unlicensed spectrum refers to the above-mentioned unlicensed spectrum A, i.e., the shared spectrum.

[0152] For the sidelink transmissions over unlicensed spectrum, whether the OCB requirement is needed to be complied with is depending on region regulation. Therefore, for an unlicensed spectrum where OCB requirement is not required, the existing transmission scheme (in other words, contiguous RB-based transmission scheme) forsidelink physical channel and signals, which is specified in 3GPP NR Releases 16 and 17, can be reused for sidelink communication over the unlicensed spectrum. On the other hand, for an unlicensed spectrum where OCB requirement is required, the interlaced transmission (interlace RB-based transmission) scheme can be applied to sidelink communication over the unlicensed spectrum.

[0153] In the present disclosure, to achieve a flexible and efficient design, a parameter A (i.e., a higher layer parameter A) is introduced to indicate which scheme of the contiguous RB-based transmission scheme and the interlace RB-based transmission scheme is applied for the sidelink transmission in a resource pool or in a SL BWP. Additionally or alternatively, in the present disclosure, the parameter A may be used to indicate whether OCB requirement is required for a SL BWP or not.

[0154] In the present disclosure, the UE 102 and / or the bases station 160 may determine, based on whether the parameter A is configured, whether interlace RB-based transmission or contiguous RB-based transmission is used for SL transmission (i.e., PSSCH / PSCCH transmission) in the resource pool.

[0155] In a case that a SL BWP configuration or the resource pool configuration includes the parameter A (i.e., the parameter A is present or is configured in the SL BWP configuration or the resource pool configuration), the UE 102 may determine the SL BWP or the resource pool is configured with interlace RB-based transmission, that is, the UE 102 may determine interlace RB-based transmission is used for the PSCCH / PSCCH transmission and / or the PSFCH transmission in the SL BWP provided by the SL BWP configuration or in the resource pool provided by the resource pool configuration, and / or, may determine OCB requirement is required for the SL BWP provided by the SL BWP configuration or for the resource pool provided by the resource pool configuration.

[0156] In a case that a SL BWP configuration or a resource pool configuration does not include the parameter A (i.e., the parameter A is not present or is not configured in the SL BWP configuration or the resource pool configuration), the UE 102 may determine that the SL BWP or the resource pool is configured with contiguous RB- based transmission and may determine the SL BWP or the resource pool is not configured with interlace RB-based transmission. In this case, interlace RB-based transmission is not used for the PSCCH / PSCCH transmission and / or the PSFCH transmission in the SL BWP provided by the SL BWP configuration or in the resourcepool provided by the resource pool configuration, and / or, the UE 102 may determine OCB requirement is not required for the SL BWP provided by the SL BWP configuration or for the resource pool provided by the resource pool configuration.

[0157] Additionally or alternatively, in the present disclosure, the UE 102 and / or the bases station 160 may determine, based on how the parameter A is configured, whether interlace RB-based transmission or contiguous RB-based transmission is used for SL transmission (i.e., PSSCH / PSCCH transmission) in the resource pool. The parameter A may be set to one of “a first value” and “a second value”. Then, in a case that the parameter A is present (or is configured) and the parameter A is set to “a first value”, the UE 102 may determine that the SL BWP or the resource pool is configured with interlace RB-based transmission. On the other hand, in a case that the parameter A is present (or is configured) and the parameter A is set to “a second value”, the UE 102 may determine that the SL BWP or the resource pool is configured with contiguous RB-based transmission.

[0158] In the present disclosure, the parameter A may be a common parameter to a plurality of SL resource pools which are configured within a SL BWP. That is, a SL BWP configuration may include the parameter A such that the parameter A is a common indication of which scheme is applied to all the resource pools which are configured in the SL BWP provided by the SL BWP configuration. Specifically, in a case that the SL BWP configuration includes the parameter A or in a case that the SL BWP configuration includes the parameter A and the parameter A is set to “a first value”, the interlaced transmission scheme is applied to all the resource pools configured in the SLBWP. That is, the UE 102 may determine to use interlaced RB-based transmission for sidelink transmission / reception in all the resource pools configured in the SL BWP. In a case that the SL BWP configuration does not include the parameter A or in a case that the SL BWP configuration includes the parameter A and the parameter A is set to “a second value”, the contiguous RB-based transmission is applied to all the resource pools configured in the SL BWP. That is, the UE 102 may determine to not use interlaced transmission scheme and to use the contiguous RB-based transmission scheme for sidelink transmission / reception in all the resource pools configured in the SL BWP.

[0159] Additionally or alternatively, the parameter may be a dedicated parameter specific to a resource pool. That is, a resource pool configuration may include the parameter A such that the parameter A is a specific indication of which scheme isapplied for a resource pool provided by the resource pool configuration. Specifically, in a case that a resource pool configuration includes the parameter A or in a case that the resource pool configuration includes the parameter A and the parameter A is set to “a first value”, the interlaced transmission scheme is applied to a resource pool configured by the resource pool configuration. That is, the UE 102 may determine to use interlaced RB-based transmission for sidelink transmission / reception in the resource pool. In a case that a resource pool configuration does not include the parameter A or in a case that the resource pool configuration includes the parameter A and the parameter A is set to “a second value”, the contiguous RB-based transmission scheme is applied to a resource pool configured by the resource pool configuration. That is, the UE 102 may determine to not use interlaced transmission scheme and determine to use the contiguous RB-based transmission scheme for sidelink transmission / reception in the resource pool.

[0160] For convenience of illustration, hereinafter, the first case can be referred to as the case that the SL BWP or the SL resource pool is configured with contiguous RB- based transmission, while the second case can be referred to as the case that the SL BWP or the SL resource pool is configured with interlace RB-based transmission.

[0161] In the present disclosure, for a carrier with a SCS u, a number of intra-cell guard bands may be configured on the carrier with the SCS u. Each intra-cell guard band is defined by a start common resource block and a size in number of common resource blocks. For each intra-cell guard band, the start common resource block and the size in number of common resource blocks are provided by parameters, for example, parameters startCRB and nrofCRBs, respectively. The size of a guard band can be configured as 0 RB or non-zero RBs. For a carrier, if information of the intra-cell guard bands is not configured by parameters, the intra-cell guard bands may be predefined or predetermined for the carrier with a SCS u.

[0162] The intra-cell guard bands separate RB sets in the carrier with the SCS u. The number of intra-cell guard bands on a carrier with a SCS can be denoted as ARB-set -1. That is, the UE is provided with ARB-SBI -1 intra-cell guard bands on a carrier. The ARB-set -1 intra-cell guard bands separate ARB-SU RB sets in a carrier. That is, the number of RB set for the carrier is ARB-set. Each RB set is defined by a start common resource block and an end common resource block in the frequency domain. The UE may determine a start common resource block and an end common resource block for an RBset based on the information of the intra-cell guard bands. Then an RB set consists of a plurality of contiguous common resource blocks in the frequency domain. For a carrier with different SCSs, an RB set may include different numbers of common resource blocks. For example, in a case that subcarrier spacing equals to 15KHz, the number of resource blocks within an RB set may be configured to be between 100 and 110. In a case that subcarrier spacing equals to 30kHz, the number of resource blocks within an RB set may be configured to be between 50 and 55. However, as an exception, for a resource pool, at most one RB set may be configured to contain 56 resource blocks. Specifically, a single RB set is defined by a starting common RB and an ending common RB in the frequency domain.

[0163] A UE may be configured with one or more SL BWP on the carrier with the SCS u. In the frequency domain, a SL BWP may be configured to include one or more RB sets on the carrier. The number of the one or more RB sets within a SL BWP are based on the configured bandwidth of the SL BWP. The one or more RB sets within a SL BWP can be denoted as ARB-setBWPwhere A?RB-sctBWPcan be less than or equal to AAB- set. The one or more RB sets within a SL BWP are indexed from 0 to A / RB-setBWP-1 in the order of increasing frequency of the SL BWP and starting at the lowest frequency.

[0164] Likewise, the UE may be configured with one or more SL resource pools within a SL BWP on the carrier with the SCS u. In the frequency domain, a SL resource pool may be configured to include one or more RB sets within the SL BWP on the carrier. The number of RB sets included in a SL resource pool are based on the configured bandwidth of the resource pool, The RB sets included in a SL resource pool can be denoted as A'RB-SCSR Pwhere AA<B-setRPcan be less than or equal to Azi<B-sctBWP. The RB sets included in a resource pool are indexed from 0 to 2VRB-setRP-1 in the order of increasing frequency of the resource pool and starting at the lowest frequency.

[0165] In the present disclosure, a SL BWP and / or a resource pool may be divided into one or more RB sets, where each of the one or more RB sets does not overlap with each other in the frequency domain. That is, the one or more RB sets do not have overlapping RBs in the frequency domain. The one or more RB sets within the resource pool are indexed from 0 in the order of increasing frequency of the one or more RB sets.

[0166] Additionally or alternatively, a guard band including zero, one or multiple RBs may separate two consecutive (or adjacent) RB sets amongst the one or more RB sets within a resource pool or a SL BWP. In other words, in the frequency domain, a SLBWP or a SL resource pool may include one or more RB sets and zero, one or more guard bands wherein one guard band is located between two adjacent RB sets.

[0167] In the present disclosure, in a resource pool, the sub-channel is a resource allocation granularity in frequency domain for SL transmission. Therefore, how to make the SL transmissions meet OCB and PSD requirement depends on how to design the sub-channel structure. In other words, how to determine sub-channels in a resource pool depends on whether the resource pool is configured with contiguous RB -based transmission or interlace RB-based transmission.

[0168] In the first case, the UE 102 may determine that a sub-channel consists of multiple contiguous PRBs in frequency domain, while in the second case, the UE 102 may determine that a sub-channel includes PRBs of one or more interlaces contained in an RB set. In the first case, the determination of sub-channel in a resource pool is specified in the Figure 7. The determination of sub-channels for the first case is similar as the existing design of sub-channel specified in NR Releases 16 and 17 where a subchannel consists of contiguous PRBs in the frequency domain. In the second case, a sub-channel may be associated with one or more interlaces. That is, a sub-channel may include PRBs of one or more interlaces contained in an RB set in the frequency domain where the PRBs of one or more interlaces are not contiguous in the frequency domain. An RB set of a resource pool consists of one or more sub-channels in the frequency domain. A resource pool consists of one or more sub-channels in the frequency domain.

[0169] Figure 7 is a diagram illustrating one example 700 of a resource pool configuration in time and frequency domain. In the Figure 7, the resource pool is configured with the contiguous RB-based transmission indicated by the parameter A, that is, the first case. A PSSCH transmission / reception is performed in one or more contiguously allocated sub-channels in the frequency domain where each sub-channel consists of multiple contiguous RBs in the frequency domain. The SCS of the resource pool may be 15kHz, 30kHz or 60kHz.

[0170] As illustrated in the Figure 7, a resource pool within a SL BWP can be divided into one or multiple contiguous sub-channels in the frequency domain. That is, a resource pool within a SL BWP consists of Asubchanneiszcontiguous sub-channels in the frequency domain. The number of Mubchannei51,is indicated by a parameter sl- NumSubchannel included in the configuration of the resource pool. Each sub-channel includes a number of contiguous RBs in the frequency domain. The number ofcontiguous RBs is indicated by a parameter sl-SubchannelSize included in the configuration of the resource pool. For illustration, the number of contiguous RBs indicated by the parameter sl-SubchannelSize can be denoted as Asub.

[0171] In the Figure 7, each block in the frequency domain represents a sub-channel of the resource pool 701. For example, in the Figure 7, the parameter sl-NumSubchannel indicates that Mubchannei51is 4. That is, the resource pool 701 consists of 4 contiguous sub-channels in the frequency domain. The first RB of the first sub-channel of the resource pool 701 in the SL BWP may be indicated by a parameter sl-StartRB- Sub channel. The first sub-channel of a resource pool refers to a sub -channel with the lowest subchannel index in the resource pool. In the Figure 7, the subchannel #0 is the first sub-channel of the resource pool 701, that is, the sub-channel with the lowest subchannel index 0. As shown in the Figure 7, the subchannel #0 includes 7<Sub contiguous PRBs starting from the PRB indicated by the parameter sl-StartRB- Subchannel; the subchannel #1 includescontiguous PRBs starting from a PRB adjacent to the lastRB of the subchannel #0; the subchannel #2 includes Asub contiguous PRBs starting from a PRB adjacent to the last RB of the subchannel #1 ; subchannel #3 includes Asub contiguous PRBs starting from a PRB adjacent to the last RB of the subchannel #2.

[0172] In the Figure 7, in a case that the resource pool 701 includes one RB set, a sub-channel includes or consists of RBs in the RB set. In a case that the resource pool 701 includes multiple RB sets and one or more guard bands, for sub-channels in the resource pool 701, some sub-channels may consist of RBs in one RB set, some subchannels may consist of RBs in two RB sets and RBs in one guard band, and / or some sub-channels may consist of RBs in one RB set and RBs in one guard band,.

[0173] In the second case, for a resource pool that is configured with interlace RB- based transmission, each RB of the resource pool is mapped to an RB of an interlace m. Furthermore, each RB within a resource pool is mapped to an interlace. In other words, in the present disclosure, a resource pool may consist of a plurality of interlaces. In the frequency domain, a resource pool is divided into a number of interlaces M where each interlace consists of non-contiguous (common) resource blocks. As above-mentioned, the value of M is determined per SCS.

[0174] Figure 8 is a diagram illustrating one example 800 of configurations of a SL BWP and SL resource pools.

[0175] As in the Figure 8, a CRB grid is used to represent the common resource blocks in a carrier with a SCS, That is, a CRB index is used to represent a CRB in the carrier. The CRBs in the carrier are indexed from 0 in an order of increasing frequencies and starting from point A. Here, as an example in the Figure 8, the carrier 801 uses the subcarrier spacing configuration ^=1, i.e., the SCS = 30kHz. The starting position AgriTtort"' of the carrier 801 is given based on the value of an offset 802 (i.e. Ocamer) indicated by a parameter (e.g., the above-mentioned offsetToCarrier). That is, the carrier 801 starts from the CRB with index 2, i.e., the N&idstar!,IJ= 2, and includes a plurality of contiguous CRBs with index from 2 to 107. That is, the carrier bandwidth Agrid^"" of the carrier 801 in number of RBs is 106.

[0176] Each CRB on the carrier is mapped to an interlace m where the mapping between CRBs and interlaces are performed cyclically from 0 to M-\ in an order of increasing frequencies of CRBs. As in the Figure 8, CRBs on the carrier are mapped to an interlace cyclically from 0 to 4 in the order of increasing frequencies of the CRBs and starting from the lowest frequency of a CRB.

[0177] As illustrated in the Figure 8, a number of intra-cell guard band is equal to 1, i.e., ARB-set -1=1. As above-mentioned, the intra-cell guard band 803 can be defined by a start CRB and a size in number of CRBs provided by a parameter startCRB and a parameter nrofCRBs, respectively. Specifically, the parameter startCRB indicates an RB offset relative to the starting CRB of the carrier 801. A CRB index of a starting CRB of an intra-cell guard band is given by its corresponding parameter startCRB and the Agrid'stort’'wof the carrier 801. In the Figure 8, the parameter startCRB indicates an RB offset as 50. The starting CRB of the intra-cell guard band 803 is determined by the summation of the RB offset and the Agridi'tort"“, i.e., the starting CRB of the intra-cell guard band 803 is the CRB with index 52. And the intra-cell guard band 803 includes 6 CRBs that is provided by the parameter nrofCRBs.

[0178] Then the intra-cell guard band 803 separates two RB sets 804 and 805 in the carrier 801, i.e., ARB-set=2. Within the carrier, the RB sets are indexed from 0 to ARB-set -1 in an order of increasing frequencies. The RB set 804 can be indexed with 0, i.e., the RB set 804 refers to the RB set 0 within the carrier 801 . Likewise, the RB set 805 can be indexed with 1, i.e., the RB set 805 refers to the RB set 1 within the carrier 801.

[0179] The starting position (the starting CRB) of the RB set 804 is the starting position Agrid^'^' of the carrier 801 . The ending CRB of the RB set 804 is determinedbased on the starting positionof the carrier 801 and the RB offset provided by the parameter startCRB for the intra-cell guard band 803. Additionally, the starting CRB of the RB set 805 is determined based on the starting positionSof the carrier 801, the RB offset provided by the parameter startCRB for the intra-cell guard band 803, and the size of the intra-cell guard band 803 by the parameter nrofCRBs. The ending CRB of the RB set 805 is determined based on the starting positionof the carrier 801 and the size of the carrier 801.

[0180] In the present disclosure, a SL BWP can be configured to include one, more or all RB sets within the carrier. In the Figure 8, a SLBWP 806 is configured to include all RB sets within the carrier 801. That is, the number of RB sets within the SL BWP806 is same as that within the carrier 801. Likewise, the RB sets within a SL BWP are numbered in increasing order from 0.

[0181] A PRB grid is used to represent the physical resource blocks in a SL BWP. That is, a PRB index is used to represent a PRB in the SL BWP. The PRBs in the BWP are indexed from 0 in an order of increasing frequencies. A PRB in a SL BWP corresponds to a CRB in a carrier. Likewise, a PRB in a BWP corresponds to an RB of an interlace m in a carrier. As illustrated in the Figure 8, the PRB with index 0 corresponds to the CRB with index 2, the PRB with index 1 corresponds to the CRB with index 3, and so on. Likewise, the PRB with index 0 corresponds to an RB of interlace m=2. The PRB with index 1 corresponds to an RB of interlace m=3.

[0182] In various examples or various implementations of the present disclosure, one or more SL resource pools can be configured within a SL BWP on the carrier with the SCS u. A SL resource pools can be configured to include one or more RB sets of a SL BWP in the frequency domain.

[0183] As illustrated in Figure 8, two SL resource pools, i.e., a SL resource pool807 and a SL resource pool 808 are configured in the SL BWP 806. The SL resource pool 807 is configured to include the RB set 804, the RB set 805, and the guard band 803 in the frequency domain. The SL resource pool 808 is configured to include the RB set 805 in the frequency domain. That is, different SL resource pools can be configured with different number of RB sets within a SL BWP, which are depending on configured bandwidths of the resource pools. The RB sets included in a SL resource pool can be denoted aswhere ARB-setRPcan be less than or equal to ARB-setBWP. The RB sets included in a resource pool are indexed from 0 to A7<B-setRP-1 in the order of increasingfrequency of the resource pool and starting at the lowest frequency. The resource pool807 includes ATB-SMRP ::U RB sets and the resource pool 808 includes JVRB-setRP=l RB set.

[0184] In the Figure 8, the resource pool 807 starts in a RPB with index 0 relative to the starting PRB of the SL BWP (i.e., PRB with index 0), while the resource pool808 starts in a RPB with index 56 relative to the starting PRB of the SL BWP (i.e., PRB with index 0). A SL BWP and / or a resource pool is configured not to include parts of an RB set. In the present disclosure, a SL BWP and / or a resource pool may be configured to start on an RB with a lowest CRB index within a first RB set and to end an RB with a largest CRB index within a second RB set. The first RB set and the second RB set can refer to a same RB set or different RB sets within the carrier. In other words, a starting RB of a SL BWP and / or a SL resource pool is a starting RB of an RB set. Likewise, an ending (last) RB of a SL BWP and / or a SL resource pool is an ending RB of an RB set.

[0185] Hereinafter, mapping (determination) between sub-channel (s) and interlace(s) is illustrated for a resource pool where interlaced transmission scheme is configured. In the second case, a sub-channel is defined and indexed within 1 RB set within a resource pool. That is, the mapping between sub-channel and interlace(s) is performed in each RB set within a resource pool. In the present disclosure, the number of one or more interlaces to be included in a sub-channel may be provided by a parameter. That is, a parameter can be introduced to indicate the number of above- mentioned one or more interlaces to the UE 102. For example, a parameter B is introduced to indicate K interlace(s) wherein 1 sub-channel includes the K interlaces within 1 RB set. That is, K interlaces within 1 RB set are formed to a sub-channel. A sub-channel may consist of K interlaces within 1 RB set. The value of K can be equal to 1 or larger than 1. For example, in case of SCS=15kHz (i.e., A / =10), the value of K indicated by the parameter B may be 1, 2, 5, or 10. In case of SCS=30kHz (i.e., M=5), the value of K indicated by the parameter B may be 1 or 5.

[0186] Additionally or alternatively, the SL resource pool configuration may not include the parameter B. The UE 102 may determine the value of K as a default value or a predefined value. For example, in a case that the SL resource pool configuration may not include the parameter B, the UE 102 may determine A=l. That is, if a SL resource pool configuration aims to set K as the default value, the SL resource poolconfiguration is not necessary to always include the parameter B so that signaling overhead of the parameter B can be reduced.

[0187] To determine or identify each sub-channel in an RB set, besides determining the number of interlaces to be included in a sub-channel, the UE 102 also needs to determine a starting interlace index for each sub-channel or at least for a first subchannel in the RB set. The first sub-channel in an RB set means a sub-channel with the lowest sub-channel index (i.e., index 0) in the RB set. In other words, within an RB set, the sub-channel is indexed starting from index 0. The sub-channel within index #0 in an RB set can be referred to as the first sub-channel in the RB set.

[0188] In the present disclosure, the UE 102 may determine that the starting interlace index for the first sub-channel in each RB set is the interlace index 0. That is, the sub-channel with index 0 includes K interlaces starting from a starting interlace index 0. For each RB set in a resource pool, 1 sub-channel is defined within 1 RB set, and is incrementally indexed in increasing order of interlace indexes starting from interlace index 0. Within an RB set, the starting interlace index for a sub-channel with index i is an interlace index successively following the interlace index of the last interlace included in the sub-channel with index z-1. Specifically, the UE 102 may determine that a sub-channel with an index i includes K interlace(s) with interlace index(es) calculated as (i*K + j) where i = 0, 1, ..., (dV / ZX-1), and j=0, 1 , ..., K-\. The M is 10 in a case that a subcarrier spacing (SCS) of the SL BWP is 15kHz and 5 in a case that the SCS is 30kHz. (MIK) is the number of sub-channels included in each RB set in the resource pool. For convenience of illustration, MubChannei1*5861is used to denote the number of sub-channels for each RB set, that is MubChannei1^864= (MIK).

[0189] As long as the UE 102 determines which interlace(s) among M interlaces to be included in a sub-channel, the UE 102 is able to determine which resources blocks to be included in the sub-channel. In other words, mapping between sub-channel and interlace(s) also means mapping between sub-channel in an RB set and resource blocks in one or more interlaces contained within the RB set. For an RB set, a sub-channel includes resource blocks in respective determined K interlace(s) contained within the RB set. That is, for an RB set, resource blocks in K interlace(s) contained within the RB set are mapped or grouped to 1 sub-channel in the RB set. Specifically, for a subchannel with an index i in an RB set where i = 0, 1 , . . . , (MubChanneiRBset-1), the subchannel with index i includes resource blocks in K interlace(s) with interlace index(es)calculated as (i*K + j) contained within the RB set. Herein, j=0, 1, K-l. In other words, the UE may determine resource blocks of a sub-channel in an RB set as an intersection of the RBs of the determined K interlaces and the RB set.

[0190] In the present disclosure, for an interlace with index, the number of resource blocks in the interlace contained within an RB set may be same as or different from that of resource blocks in the interlace contained within another RB set. Likewise, for an RB set, the number of resource blocks in an interlace contained within the RB set may be same as or different from that of resource blocks in another interlace contained within the RB set. Therefore, within an RB set, although a sub-channel includes same number of interlaces within the same RB set, the number of resource blocks included in a sub-channel may be same as or different from that of resource blocks included in another sub-channel. Likewise, for a sub-channel with a same index i in different RB sets, the number of resource blocks included in the sub-channel with index i in an RB set may be same as or different from that of resource blocks included in the sub-channel with index i in another sub-channel RB set.

[0191] Figure 9 is a diagram illustrating one example 900 of sub-channel determination in a resource pool by a UE 102. In the example 900, K is equal to 1, that is, one sub-channel includes 1 interlace within 1 RB set. To be specific, 1 sub-channel consists of resource blocks of K=\ interlace within 1 RB set. A SL resource pool 901 in the Figure 9 is as same as the SL resource pool 807 that is specified in the Figure 8. That is, the above description for the resource pool 807 in the Figure 8 can be applied to that for the SL resource pool 901. The SCS of the resource pool is 30kHz and, as above-mentioned, the number of interlaces M is 5 for 30KHz SCS.

[0192] As in the Figure 9, the resource pool 901 is configured to include an RB set 902, an guard band 903, and, an RB set 904 in the frequency domain. The UE 102 may determine sub-channels for each RB set in the resource pool 901. The RB set 902 includessub-channels. The sub-channels within in the RB set 902 are indexed from 0 to 4. Within the RB set 902, the sub-channel with index 0 includes the interlace with index m = 0, the sub-channel with index 1 includes the interlace with index m = 1, sub-channel with index 2 includes the interlace with index m = 2, sub-channel with index 3 includes the interlace with index m = 3, and, subchannel with index 4 includes the interlace with index m = 4. In other words, within the RB set 902, the sub-channel with index 0 includes resource blocks in the interlace withindex m = 0 contained in the RB set 902, the sub-channel with index 1 includes resource blocks in the interlace with index m = 1 contained in the RB set 902 and so on.

[0193] Likewise, the RB set 904 includes5 sub-channels. The sub-channels within in the RB set 904 are indexed from 0 to 4 as well. Within the RB set 904, the sub-channel with index 0 includes the interlace with index m = 0, the sub-channel with index 1 includes the interlace with index m = 1, sub-channel with index 2 includes the interlace with index m = 2, sub-channel with index 3 includes the interlace with index m = 3, and, sub-channel with index 4 includes the interlace with index m = 4. In other words, within the RB set 904, the sub-channel with index 0 includes resource blocks in the interlace with index m = 0 contained in the RB set 904, the sub-channel with index 1 includes resource blocks in the interlace with index m = 1 contained in the RB set 904 and so on.

[0194] As in the Figure 9, a sub-channel is defined within each RB set and does not include resource block in guard band 903. And the total number of sub-channels in the resource pool 901 , which can be denoted as, is 10. That is, in the second case, the total number of sub-channels included in a resource pool (i.e., Asubchanneiffi) is calculated or determined by the UE 102 based on the parameter B (i.e., the value of K), the value of M, and the number ofRB set(s) contained in the resource pool. Specifically, the value of may be determined or calculated as (MIK) * ARB-setRPwhereis the number of RB set(s) contained in the resource pool. On the other hand, as above-mentioned in the Figure 7, in the first case, the total number of sub-channels included in a resource pool (i.e., ) is indicated or determined by the parametersl-NumSub channel.

[0195] In the frequency domain, the frequency domain resource allocation granularity is one sub-channel for a PSSCH transmission. That is, for PSSCH transmission, the frequency domain unit is a sub-channel. A PSSCH transmission may be performed in one or more contiguous sub-channels in the frequency domain.

[0196] Regardless of whether the resource pool is configured with contiguous RB- based transmission or interlace RB-based transmission, in the time domain, the UE may be configured with a set of slots assigned to a resource pool for SL transmission. For example, as illustrated in the Figure 7, each block in the time domain represents a slot in the set of slots assigned to the resource pool 701. The slot indexes in the Figure 7 refer to the logical slot indexes. The OFDM symbols within a slot assigned for sidelinktransmission are provided by parameters included in the (pre-)configuration. To be specific, SL transmissions can start from a first symbol indicated by a parameter sl- StartSymbol and be within a number of consecutive symbols indicated by a parameter sl-LengthSymbols. As in the Figure 7, the duration 702 starts at the third OFDM symbol which is indicated by the parameter sl-StartSymbol and consists of 11 consecutive OFDM symbols which is indicated by the parameter sl-LengthSymbols, For a slot indicated for transmission of S-SS / PSBCH blocks, the first symbol and the number of consecutive symbols is predetermined.

[0197] For a sidelink transmission over the unlicensed spectrum, the UE 102 may apply LBT before performing a SL transmission. When LBT is applied, the UE 102 senses the channel to determine whether the channel is free or busy. For the UE 102, both Physical layer (Layer 1, Physical entity) and MAC layer (MAC entity) are involved in LBT operation. Specifically, Physical layer (i.e., a layer lower than the MAC layer) may perform an LBT procedure before a SL transmission. In a case that the channel is sensed free, the UE 102 (i.e., the Layer 1 of the UE 102) may perform the SL transmission. On the other hand, in a case that the channel is sensed busy, the UE 102 (i.e., the Layer 1 of the UE 102) may not perform the SL transmission. The terms “A channel is sensed busy”, “the UE detects LBT failure on the channel” and “the channel is identified as being occupied” have same meaning and can be used interchangeably. Likewise, the terms “A channel is sensed free”, “the UE does not detect LBT failure on the channel” and “the channel is identified as not being occupied” have same meaning and can be used interchangeably. If the UE detects LBT failure on a channel, the UE cannot access or fails to access the channel for a following SL transmission. If the UE does not detect LBT failure on a channel, the UE can access the channel for a following SL transmission.

[0198] When the UE 102 performs the LBT procedure before an SL transmission and the SL transmission is not performed by the UE 102, the physical layer (Layer 1) of the UE 102 may send an LBT failure indication to the MAC entity. That is, if the UE 102 fails to access the channel(s) prior to an intended SL transmission, the physical layer of the UE 102 may notify higher layers about the channel access (LBT) failure.

[0199] On the other hand, when the UE 102 performs the LBT procedure before an SL transmission and the SL transmission is performed by the UE 102, the physical layer of the UE 102 may not send an LBT failure indication to the MAC entity. That is, if theUE 102 accesses the channel(s) prior to an intended SL transmission, the physical layer of the UE 102 may not notify higher layers about the channel access (LBT) failure.

[0200] Here, the SL transmission can be any SL transmission such as S-SSB transmission, PSFCH transmission, and PSCCH / PSSCH transmission.

[0201] In the present disclosure, LBT failure indication is per RB set. That is, LBT failure is detected per RB set. The (pre-)configuration may provide the following parameters used for detection of consistent LBT failure, e.g., Ibt- FailurelnstanceMaxCount and Ibt-FailureDetectionTimer. The Ibt- FailurelnstanceMaxCount indicates a number and determines after how many LBT failure indications received from the physical layer the UE triggers SL LBT failure recovery. The Ibt-FailureDetectionTimer indicates a value corresponding to a duration in unit of ms.

[0202] The MAC entity may maintain a timer Ibt-FailureDetectionTimer and a counter LBT_COUNTER for each RB set. The counter is a counter for LBT failure indication which is initially set to 0. For each RB set, if a LBT failure indication has been received from lower layers (Physical layer), the MAC entity may start or restart the Ibt-FailureDetectionTimer and increment the counter LBT_COUNTER by 1. If the value of the counter LBT_COUNTER is equal to or larger than the number indicated by the Ibt-FailurelnstanceMaxCount, the MAC entity may trigger consistent LBT failure for the RB set. In other words, the UE 102 may count LBT failure indications from the physical layer to the MAC entity for an RB set and in a case that the counted number of the LBT failure indications is equal to or larger than the number indicated by the Ibt- FailurelnstanceMaxCount, the UE 102 may trigger consistent LBT failure for the RB set and / or may determine that consistent LBT failure is detected on the RB set. In addition, in a case that the timer Ibt-FailureDetectionTimer expires, the MAC entity may set the counter LBT_COUNTER to 0.

[0203] As above-mentioned, sidelink resource allocation mode 2 is for UE autonomous resource selection. The UE may autonomously determine to select resources for PSSCH transmission based on a sensing-based procedure. The procedure of the sensing and resource selection is to determine a subset of candidate resources which are reported by the physical layer of the UE to higher layers in PSSCH resource selection in sidelink resource allocation mode 2. Candidate resources in the subset are available for PSSCH transmission and MAC entity may randomly select one or multipletime and frequency resources for one transmission opportunity from the subset indicated by the physical layer.

[0204] In the present disclosure, the procedure of the sensing and resource selection can be also called as “the procedure of determining a subset of candidate resources which will be reported by the physical layer of the UE 102 to higher layers of the UE 102 in PSSCH resource selection in sidelink resource allocation mode 2” or as “the procedure of determining a subset of candidate resources for a PSSCH transmission”.

[0205] In the present disclosure, the higher layer may trigger a procedure of determining a subset of candidate resources for the PSSCH transmission in a slot n of a resource pool. In the present disclosure, for a sidelink transmission over the unlicensed spectrum, a resource pool where sidelink transmission is performed can be configured with contiguous RB-based transmission or interlace RB-based transmission. The slot n can be regarded as the time of trigger n for the procedure. For the procedure of sensing and resource selection, the timeline of a sensing window and a resource selection window are determined based on the time of the trigger slot n. The slot n herein refers to a slot in the resource pool (i.e., a slot with logical slot index n in the resource pool). Additionally, unless otherwise specified, a slot that would be described or explained below for the procedure refers to a slot of the resource pool, i.e., a logical slot that belongs to the resource pool.

[0206] In various embodiments and implementations of the present disclosure, the higher layer is a layer higher than physical layer. That is, the higher layer is higher relative to the physical layer. For example, the higher layer may be the MAC layer. Alternatively, the higher layer may be the RRC layer.

[0207] To trigger the procedure in the slot n, the higher layer may provide parameters for the PSSCH transmission to the physical layer. For example, the parameters may include a parameter indicating a resource pool from which the candidate resources are to be reported, a parameter indicating a priority of the PSSCH transmission p\, a parameter indicating a remaining packet delay budget, a parameter indicating a number of sub-channels to be used for the PSSCH transmission in a slot, and so on. The number of sub-channels to be used for the PSSCH transmission in a slot can be denoted as Zsubcn. For convenience of illustration, the parameter indicating Tsubcn can be termed the parameter C.

[0208] To process the procedure of determining a subset of candidate resources to be reported to higher layers, the UE 102 may first need to define (identify or determine) what a candidate resource is, that is, a candidate resource includes what kind of time and frequency resources within the resource selection window. In other words, what kind of time and frequency resources within the resource selection window can be defined as a candidate resource for the PSSCH transmission. The procedure of determining a subset of candidate resources for a PSSCH transmission includes several steps that are illustrated below.

[0209] In the procedure of determining a subset of candidate resources for a PSSCH transmission, the UE 102 may perform step 1 to determine or define candidate resource within a time interval. In step 1, for determining the candidate resources, the UE needs to determine a time interval [n+7), n+Z)]. The determination of candidate resources and determination of time interval are included in step 1 of the procedure. In other words, step 1 is a step of defining or determining a set of candidate resources within the resource selection window (i.e., the time interval [n+Zi, n+Z?]).

[0210] In step 1 of the procedure, the UE 102 may define the resource selection window as time interval [n+Zi, n+Tz]. The UE may determine a value for T\ to satisfy with 0<=Ti<=Tproc,i where the Tproc.i is a predefined value with respect to SCS of the resource pool. The UE may determine the value of h based on the remaining packet delay budget in slots. The selection window starts shortly after the trigger for selection of resources and cannot be longer than the remaining 1 packet delay budget.

[0211] To determine how to define the candidate resource in the procedure, in the present disclosure, the higher layer may or may not further provide a parameter E to the physical layer where the parameter E indicates a number of RB sets, LRBSet>tobe used for the PSSCH transmission in a slot. The determination of how the UE 102 determines to define a candidate resource based on the parameter C and / or the parameter E (if provided) is illustrated below.

[0212] In some embodiments, for a resource where contiguous RB-based transmission is applied, the higher layer may not provide the parameter E for the procedure of the sensing and resource selection in the resource pool. Then the UE 102 may determine to define a candidate resource based on the parameter C. Specifically, the UE 102 may determine that a candidate resource is defined as a set of UUI,CHcontiguous sub-channels with sub-channel indexes x +j in a slot where j = 0, . . . , fsubCH—!• The symbol Rx ycan be used to identify the candidate resources in the selection window, x indicates a starting sub-channel index of the candidate resource, y indicates a slot index of the candidate resource. That is, with the indicated LsubCH, each candidate resource can be identified or determined by a starting sub-channel index, and a slot index. The value of x can be taken from 1 with meetingthe condition that the value of(subCH) should be less than

[0213] In some embodiments, determination method of defining or identifying candidate resource for a resource pool where interlace RB-based transmission is applied based on whether the parameter E is indicated is provided. For a resource pool where interlace RB-based transmission is applied, the higher layer may or may not provide the parameter E for the procedure of the sensing and resource selection in the resource pool. Then the UE 102 may determine to define a candidate resource based on (i) the parameter C and / or (ii) whether the parameter E is provided or not.

[0214] In a case that the parameter E is provided to the resource pool for the procedure of the sensing and resource selection, the UE 102 may determine to define candidate resources based on the parameter C and the parameter E. Specifically, the UE 102 may determine that a candidate resource is defined as a set ofcontiguous sub-channels in LRBsetcontiguous RB sets in a slot wherethis case, candidate resources are defined to use the same number LRBSetthat is indicated by the parameter E. Meanwhile, each candidate resource includes a set ofcontiguous sub-channels in each RB set of the LRBSetcontiguous RB set(s).

[0215] Here, in some embodiments, the symbol Rr,x,ycan be used to identify the candidate resources in the selection window, r indicates a starting RB set index of a candidate resource, x indicates a starting sub-channel index of the candidate resource, y indicates a slot index of the candidate resource. That is, with the indicated Z,subCHand fRBset, each candidate resource can be identified or determined by a starting RB set index, a starting sub-channel index, and a slot index. The candidate resource includes ^subCH contiguous sub-channels starting from the sub-channel with index x in each RB set of the LRBsetcontiguous RB set(s) starting from the RB set with index r wherein the product of theHand the LRBsetis equal to the LsubCH.

[0216] Specifically, a candidate resource RTiXiy is defined as a setcontiguous sub-channels with sub-channel indexes x + j in LRBSetcontiguous RB sets with RB set indexes r + I in a slot y where j = 0, . . . , L^bak — 1, 1 = 0, . .. , LRBset~ 1-

[0217] In a case that the parameter E is not provided to the resource pool for the procedure of the sensing and resource selection, UE 102 may determine to define a candidate resource based on the parameter C. The UE 102 may determine that a candidate resource is defined as a setcontiguous sub-channels in LRBsetcontiguous RB sets in a slot where the value of LRBsetcanbe one of this case, for theprocedure of sensing and selection procedure, candidate resources may have different numbers (values) of LRBset- That is, for a procedure of sensing and resource selection, a candidate resource can be defined within 1 RB set and can be defined across multiple RB sets. The value of LRBsetcanhe taken from a range {1, ... , min{LsubCH, JVRB..set}}. Although the value range of LRBset is within {1, ... , min{LsubCH, V?B-SJ}: the value of LRBsetshould be taken to ensure the outcome of (LSubCH / LRBset) 's aninteger.

[0218] Here, in some embodiments, the symbol RriXycan be used to identify the candidate resources in the selection window, r indicates a resource indication value (RIV) which corresponds to a starting RB set index (r0) and the number of contiguous RB sets (Z>RBset) f°rthe candidate resources, x indicates a starting sub-channel index of the candidate resource, and y indicates a slot index of the candidate resource. That is, with the indicated LsubCH,each candidate resource can be identified or determined by a RIV of RB set allocation information, a starting sub-channel index, and a slot index. The candidate resource includes contiguous sub-channels starting from the subchannel with index x in each RB set of the LRBsetcontiguous RB set(s) starting from the RB set with index r0wherein the product of theand the LRBSet is equal tothe isubCH-

[0219] Specifically, a candidate resource RriXiy is defined as a set ofcontiguous sub-channels with sub-channel indexes x + j in LRBset contiguous RB sets with RB set indexes r0+ I in a slot1, the values of r0and LRBsetare given based on the RIV r, the value of'soutput of dividing LsubCHby LRBset.

[0220] For 0<= RIV < iVRg.sel(2V^B_set+l) / 2, the RIV corresponds to a starting RB set index r0and a number of contiguous RB sets LRBset where the RIV is defined by:else

[0221] Additionally or alternatively, in some embodiments, the symbolcanbe used to identify the candidate resources in the selection window. I indicates a number of contiguous RB sets, LRBset;used for the candidate resource, r indicates a starting RB set index for the candidate resource, x indicates a starting sub-channel index of the candidate resource, and y indicates a slot index of the candidate resource. That is, with the indicated LsubcH, each candidate resource can be identified or determined by a number of contiguous RB sets, a starting RB set index, a starting subchannel index, and a slot index. The candidate resource includescontiguous sub-channels starting from the sub-channel with index x in each RB set of the LRBset contiguous RB set(s) starting from the RB set with index r wherein the product of thesubCHand the LRBsetis equal to the LsubCH.

[0222] Specifically, a candidate resource Ri>r,x,y is defined as a set ofcontiguous sub-channels with sub-channel indexes x -I- j in LRBsetcontiguous RB sets with RB set indexes r + k in a slot

[0223] In various embodiments and implementations of the present disclosure, the value of r can be taken from 0,1, ... ,— 1 with meeting the condition that the value of (r + lRBset— 1) should be less than iV[^.set. The value of x can be taken from 0,1,~ with meeting the condition that the value of (x + 1-^bcn — 1) should be less than- fo addition, variables r, x, y (or I, r, x, y) are not ordered in the symbol such that the variables can be specified in any sequence.

[0224] According to above embodiments, each candidate resource can be uniquely identified by respective symbol such that physical layer and higher layer can have same common understanding on identifying candidate resources within the selection window without ambiguity. A more efficient sidelink communication system is provided.

[0225] In the present disclosure, the UE 102 shall assume any candidate resource is in a slot y within the time interval [n+Z), n+Zz]. The UE 102 may not determine a resource in a slot outside the time interval [n+Z), n+Zy as a candidate resource.

[0226] In the present disclosure, the term “a set ofcontiguous sub-channels in LRBsetcontiguous RB sets” means that “there is one setcontiguous subchannels in each RB set of the LRBsetcontiguous RB sets”. Therefore, for a resource that is defined or determined as a set of L^CH contiguous sub-channels in LRBsetcontiguous RB sets, the resource includes LRBsetsets of L^CH contiguous subchannels wherein one set ofcontiguous sub-channels is contained in one RB set of the LRBsetcontiguous RB sets.

[0227] In the present disclosure, in some embodiments, in the case that the parameter E is not provided to the resource pool for the procedure of the sensing and resource selection, for the procedure, a candidate resource can be defined within an RB set (if LRBset ~ 1) and can be defined across a set of multiple RB sets (if LRBset> 1). For a candidate resource that is defined across a set of multiple RB sets, RB set indexes in the set of RB sets may be contiguous.

[0228] In the present disclosure, in some embodiments, in the case that the parameter E is provided to the resource pool for the procedure of the sensing and resource selection, for the procedure, a candidate resource can be defined with the indicated LRBsetcontiguous RB sets.

[0229] For a candidate resource, the number of sub-channels contained in the candidate resource is equal to (LsubCH / LRBset) which depends on the number of RB sets, LRBset, contained in the candidate resources. However, for a candidate resource, the product of the number of sub-channels used by a candidate resource in an RB set and the number of RB sets used by the candidate resource should be equal to LsubCHsubchannels. When a candidate resource is defined across a set of LRBsetRB sets, the number of sub-channels contained in each of the LRBsetRB sets is same and the subchannel indexes Xj where j — 0, . . . , (LsubCH / LRBset) — 1 are same as well. In other words, for a candidate resource across different RB sets, sub-channel indexes should be same in the different RB sets.

[0230] In the present disclosure, in some embodiments, the higher layer may further provide a parameter D (or information) to the physical layer. The physical layer of theUE 102 (e.g., the control unit 128 of the UE 102) may be provided by the parameter D from the higher layer of the UE 102 (e.g., MAC entity, RRC information configuration module 126) the information relating to consistent LBT failure on the resource pool. For example, the parameter D may provide information of consistent LBT failure at least for each of the RB sets contained in the resource pool. Physically layer of the UE 102 may determine the information of consistent LBT failure for each RB set in the resource pool based on the parameter D.

[0231] In the present disclosure, in some embodiments, the parameter D may be provided to a resource pool regardless of whether the resource is configured with interlace RB-based transmission or contiguous RB-based transmission.

[0232] Specifically, the parameter D may be a bit string (i.e., bitmap). In some embodiments, the length of the bit string Zbitmap can be given or determined based on the amount of the RB set(s) contained in the resource pool. For example, the length of the bit string Zbitmap can be equal to the number of RB set(s) contained in the resource pool NRB-setRP- Each bit of the bitmap corresponds to one RB set contained in the resource pool and then each bit indicates information of consistent LBT failure for its corresponded RB set, e.g., whether consistent LBT failure is detected on its corresponded RB set. In other words, the bitmap of size Zbitmap with one bitmap bit per RB set in the resource pool such that each RB set in the resource pool is addressable. The order of bitmap is such that RB set with index 0 to RB set with index (ARB-setRP-1) may be mapped from MSB to LSB. Alternatively, the order of bitmap is such that RB set with index 0 to RB set with index (NRB-setRP-1) may be mapped from LSB to MSB.

[0233] Additionally or alternatively, in some embodiments, the length of the bit string Lbitmapcan be given or determined based on the amount of the RB set(s) contained in the SL BWP. For example, the length of the bit string Zbitmap can be equal to the number of RB set(s) contained in the SL BWP NRB-setBWP. Likewise, the bitmap of size Zbitmap with one bitmap bit per RB set in the SL BWP such that each RB set in the SL BWP is addressable. The order of bitmap is such that RB set with index 0 to RB set with index (NRB-setBWP-1) may be mapped from MSB to LSB. For a resource pool, the UE 102 can determine corresponding bit(s) in the bitmap for RB set(s) contained in the resource pool depending on frequency location of the RB set(s) among the NRB-setBWPRB sets. For example, as illustrated in the Figure 8, the SL BWP 806 is configured to include NRB-setBWP=2 RB sets and the resource pool 808 includes NRB-setRP= 1 RB set.The UE 102 may determine that LSB of the bitmap of size Zbitmap = 2 is the bit corresponding to the RB set in the pool 808. Alternatively, the order of bitmap is such that RB set with index 0 to RB set with indexNRB-setBWP-1) may be mapped from LSB to MSB.

[0234] In the present disclosure, in some embodiments, the bit value can be used to indicate whether consistent LBT failure is detected in its corresponded RB set or not. Additionally or alternatively, the bit value can be used to indicate whether consistent LBT failure has not been triggered and not cancelled in its corresponded RB set or not. For example, if the bit value is 1, its corresponded RB set is determined as an RB set where consistent LBT failure is detected, and / or where consistent LBT failure has been triggered and not cancelled. If the bit value is 0, its corresponded RB set is determined as an RB set where consistent LBT failure is not detected, and / or where consistent LBT failure has not been triggered or has been cancelled. For example, if the bit value is 0, its corresponded RB set is determined as an RB set where consistent LBT failure is detected, and / or where consistent LBT failure has been triggered and not cancelled. If the bit value is 1, its corresponded RB set is determined as an RB set where consistent LBT failure is not detected, and / or where consistent LBT failure has not been triggered or has been cancelled.

[0235] Physically layer of the UE 102 may acquire the information of consistent LBT failure for each RB set in the resource pool based on respective corresponding bit value. Based on the information, the UE 102 may determine whether consistent LBT failure is detected for RB set(s) in the resource pool, which RB set(s) are the RB set(s) where consistent LBT failure is detected, and / or, which RB set(s) are the RB set(s) where consistent LBT failure is not detected.

[0236] Additionally or alternatively, in a case that the higher layer does not provide the parameter D to the resource pool from which the candidate resources are to be reported, physical layer of the UE 102 (e.g., the control unit 128 of the UE 102) may determine that there is no consistent LBT failure detected on any RB set in the resource pool.

[0237] The information of consistent LBT failure impacts the procedure of the sensing and resource selection. Currently how to execute the procedure of the sensing and resource selection based on the information of consistent LBT failure has not been specified. The present implementations of the present disclosure provide new methodsand solutions on how to execute the procedure of the sensing and resource selection over unlicensed spectrum based on the information of consistent LBT failure, which would provide a more efficient and flexible sidelink communication system.

[0238] Figure 10 is a flow diagram illustrating one implementation of a method 1000 for determination of candidate resources in a procedure of sensing and resource selection in a resource pool by a UE 102. The procedure of the sensing and resource selection is to determine a subset of candidate resources which will be reported by the physical layer of the UE 102 to the higher layer of the UE 102 in PSSCH resource selection in sidelink resource allocation mode 2. That is, the higher layer (e.g., the MAC layer) of the UE 102 may select one or more resources for PSSCH transmission from the subset of candidate resources reported from the physical layer of the UE 102. In other words, the subset of candidate resources are resources available for PSSCH transmission.

[0239] In the implementation of the present disclosure, the resource pool may include one or more RB sets in the frequency domain. As illustrated above, each RB set in the resource pool includes MubChanneiRBsetsub-channels.

[0240] The above-mentioned parameter A configures whether interlace RB-based transmission is applied in the resource pool. That is, the above-mentioned parameter A may indicate whether interlace RB-based transmission or contiguous RB-based transmission is applied in the resource pool.

[0241] In resource allocation mode 2, the higher layer of the UE 102 may request the UE 102 (i.e., the physical layer of the UE 102) to determine a subset of candidate resources from which the higher layer will select resources for PSSCH / PSCCH transmission. That is, the UE 102 may trigger 1001, a procedure of determining a subset of candidate resources for a PSSCH transmission.

[0242] In other words, the UE 102 (the physical layer or physical layer unit of the UE 102) may receive, from the higher layer of the UE 102, a request or an indication to trigger the procedure of determining a subset of candidate resources for a PSSCH transmission.

[0243] The UE 102 (the physical layer or physical layer unit of the UE 102) may further receive 1002, from the higher layer of the UE 102, a parameter indicating information of consistent LBT failure for the resource pool. The parameter is the above- mentioned parameter D.

[0244] In an example A of the present implementation, a determination method is that, in step 1 of the procedure, the UE 102 may take the information of consistent LBT failure into consideration in defining the candidate resource. The UE 102 may determine 1003 to define a candidate resource based on the parameters provided by the higher layer wherein the parameters may include the parameter C, the parameter D, and the parameter E (if provided).

[0245] The parameter D may indicate zero, one, or more RB sets where consistent LBT failure is detected in the resource pool where interlace RB-based transmission is configured. In a case that parameter D indicated that there is one or more RB sets where consistent LBT failure is detected in the resource pool, the UE 102 may determine that a candidate resource is defined as a set of L^^H contiguous sub-channels in LRBsetcontiguous RB sets in a slot within the time interval wherein any RB set of the LRBsetcontiguous RB sets of the candidate resource is not an RB set of the indicated one or more RB sets where consistent LBT failure is detected. To be specific, for a resource that includes a set of L^bcx contiguous sub-channels in LRBsetcontiguous RB sets in a slot, the UE 102 may determine that the resource is a candidate resource if any RB set of the LRBsetcontiguous RB sets of the resource is not indicated as consistent LBT failure by the parameter D, and may determine that the resource is not a candidate resource if at least one RB set of the LRBsetcontiguous RB sets of the resource is indicated as consistent LBT failure.

[0246] To be specific, as above-mentioned, the Rr,x,yor the Ri,r,x,ycan identity a resource. For example, for a resource denoted by the Rr,x,yin a case that the at least one RB set of the LRBset RB sets with RB set indexes r0+ I (or r0+ I ) is indicated as consistent LBT failure, the UE 102 may determine that the resource is not a candidate resource. On the other hand, in a case that the any of the LRBsetRB sets with RB set indexes r0+ I (or r0+ I ) has not been indicated as consistent LBT failure, the UE 102 may determine that the resource is the candidate resource. Likewise, for a resource denoted by the Ri,r,x,y, in a case that the at least one RB set of the LRBsetRB sets with RB set indexes r + / < is indicated as consistent LBT failure, the UE 102 may determine that the resource is not a candidate resource. On the other hand, in a case that the any of the LRBsetRB sets with RB set indexes r + k has not been indicated as consistent LBT failure, the UE 102 may determine that the resource is the candidate resource.

[0247] In a case that there is no RB set where consistent LBT failure is detected in the resource pool where interlace RB-based transmission is configured, the UE 102 may determine a candidate resource as a setcontiguous sub-channels in LRBsetcontiguous RB sets in a slot within the time interval.

[0248] The parameter D may indicate zero, one, or more RB sets where consistent LBT failure is detected in the resource pool where contiguous RB-based transmission is configured. In a case that parameter D indicated that there is one or more RB sets where consistent LBT failure is detected in the resource pool, the UE 102 may determine that a candidate resource is defined as a set of LsubcH contiguous subchannels in a slot within the time interval wherein any sub-channel of hsubCH contiguous sub-channels of the candidate resource does not overlap with an RB set of the indicated one or more RB sets where consistent LBT failure is detected. In other words, any subchannel of the hsubCH contiguous sub-channels of the candidate resource does not include one or multiple RBs that belong to an RB set where consistent LBT failure is detected. Therefore, for a resource that includes a set of AsubCH contiguous sub-channels in a slot, the UE 102 may determine that the resource is a candidate resource if any subchannel of the hsubcH contiguous sub-channels of the resource does not include at least 1 RB that belongs to an RB set which is indicated by the parameter D with consistent LBT failure, and may determine that the resource is not a candidate resource if at least one sub-channel of the LsubCHcontiguous sub-channels of the resource includes at least 1 RB that belongs to an RB set which is indicated as consistent LBT failure.

[0249] In the example A, upon defining the candidate resources within the time interval [n+Ti, n+Tz], the UE 102 may determine the total number of candidate resources within the time interval [n+7\ n+7Y]. The total number of candidate resources can be denoted by Motaii.

[0250] The resources that overlap with RB set(s) where consistent LBT failure is detected are not suitable to be selected as candidate resource for PSSCH transmission. Therefore, according to the example A, determining to not define these kinds of resources as candidate resources in step 1 is beneficial for execution of following steps of the procedure and can provide an efficient resource selection for PSSCH transmission.

[0251] In an example B of the present implementation, a determination method is that, in step 1 of the procedure, the UE 102 may not take the information of consistent LBT failure into consideration in defining the candidate resource. The UE 102 may determine to define a candidate resource based on the parameter C and / or the parameter E (if provided) and not based on the parameter D. The UE 102 may exclude candidate resources from the defined candidate resources based on the parameter D.

[0252] The determination of how the UE 102 determines to define a candidate resource based on the parameter C and / or the parameter E (if provided) is same as illustrated as above. The UE 102 may determine or may determine to define candidate resources within the time interval. Upon defining the candidate resources within the time interval [n+Ti, n+Ty, the UE 102 may determine the total number of candidate resources within the time interval [n+7), n+T?]. The total number of candidate resources can be denoted by Motan.

[0253] In the example B, the UE 102 may determine 1003 whether to exclude one or more candidate resources from the Motan candidate resources (i.e., above defined candidate resources) based on the parameter D.

[0254] In some embodiments, for example, the parameter D indicated that there is one or more RB sets where consistent LBT failure is detected in the resource pool wherein the resource pool is configured with interlace RB-based transmission. In this case, the UE 102 may determine whether to exclude, from the Motai2 candidate resources, a candidate resource based on whether at least one of the LRBsetcontiguous RB sets of the candidate resource is an RB set indicated as consistent LBT failure by the parameter D.

[0255] For any candidate resource in the Mtotai2 candidate resources, in a case that at least one RB set of the LRBsetcontiguous RB sets of a candidate resource is an RB set where consistent LBT failure is detected or indicated by the parameter D, the UE 102 may determine to exclude the candidate resource from the set of the Motai2 candidate resources. The UE 102 may determine the total number of remaining candidate resources after exclusion. The total number of remaining candidate resources after exclusion can be denoted by Motai3. In other words, after exclusion, the total number of candidate resources remaining in the set of the Motai2 candidate resources is denoted by MotaB.

[0256] In some embodiments, for example, the parameter D indicated that there is one or more RB sets where consistent LBT failure is detected in the resource pool wherein the resource pool is configured with contiguous RB-based transmission. In this case, the UE 102 may determine whether to exclude, from the Motan candidate resources, a candidate resource based on whether at least one sub-channel of the fsubcn contiguous sub-channels of the candidate resource overlaps with an RB set indicated as consistent LBT failure by the parameter D. In other words, the UE 102 may determine whether to exclude, from the Motai2 candidate resources, a candidate resource based on whether at least one sub-channel of the LsubCH contiguous sub-channels of the candidate resource includes at least 1 RB that belongs to an RB set indicated as consistent LBT failure by the parameter D.

[0257] For any candidate resource in the Motai2 candidate resources in a resource pool where contiguous RB-based transmission is configured, in a case that at least one sub-channel of the LsubcH contiguous sub-channels of a candidate resource includes at least 1 RB that belongs to an RB set where consistent LBT failure is detected or indicated by the parameter D, the UE 102 may determine to exclude the candidate resource from the set of the Motai2 candidate resources. The UE 102 may determine the total number of remaining candidate resources after exclusion. The total number of remaining candidate resources after exclusion can be denoted by Motai3- In other words, after exclusion, the total number of candidate resources remaining in the set of the Motan candidate resources is denoted by Motai3.

[0258] The resources that overlap with RB set(s) where consistent LBT failure is detected are not suitable to be selected as candidate resource for PSSCH transmission. Therefore, according to the example B, excluding these kinds of resources as candidate resources in step I is beneficial for execution of following steps of the procedure and can provide an efficient resource selection for PSSCH transmission.

[0259] In some embodiments, the UE 102 may be configured to execute the method in the example A in the step 1. In some embodiments, the UE 102 may be configured to execute the method in the example B in the step 1 . In some embodiments, for the UE 102, which method between the example A and the example B can be determined in 3 GPP the specification.

[0260] After executing step 1 of the procedure, the UE 102 may further execute the procedure with following steps.

[0261] In step 2, the UE 102 may define a sensing window for PSSCH monitoring by the range of slots [n-To, n-Tproc,o]. To is defined as the number of slots corresponding to 1100 ms (millisecond) or 100 ms which is indicated by parameter sl-SensingWindow . The values of Tproc.o are predefined in specification and depend on sub-carrier spacing. The UE 102 may monitor slots which belongs to the resource pool within the sensing window except for those in which its own transmission occurs. In the slots of the sensing window, the UE 102 may keep decoding PSCCH transmitted by other UEs and also measure corresponding PSSCH energy, i.e., SL-RSRP. PSCCH RSRP and PSSCH RSRP are defined as the linear average over the power contributions of the resource elements that carry DMRS associated with PSCCH and PSSCH, respectively.

[0262] The UE 102 may collect, based on received SCI format from other UEs, sensing information including information of time and frequency resources, resource reservation period value, and measured SL-RSRP. In other words, The UE 102 may determine which resources to be reserved by other UEs based on the sensing information. The UE 102 may maintain a record of which resources have been reserved by other UEs based on the decoded PSCCH information (sensing information). In the present disclosure, determining a reserved resource includes (i) the determination of frequency resource for the reserved resource, and (ii) time resource for the reserved resource. The frequency resource refers to which sub-channel(s) in which RB set(s) that the reserved resource consists of. The time resource refers to the time location (e.g., slot index) in the SL resource pool for the reserved resource.

[0263] Step 3 is a step of setting internal parameter Th(pi,p]'). The UE 102 may set the internal parameter Th(pt, pj) to the corresponding value of RSRP threshold indicated by the zthfield in sl-Thres-RSRP-List. The value of i is calculated by the formula i = pt + (pj — 1) X 8. The parameter sl-Thres-RSRP-List indicates a list of 64 RSRP thresholds and a RSRP threshold corresponds to a combination (pf, pj). Here, ptis the value of the priority field in a received SCI format 1-A and pj is the priority of the transmission of the UE 102 selecting resources. In the procedure, p, = prioTX.

[0264] Step 4 is a step of initialization of a set of candidate resources. In the step 4, the UE 102 may initialize a set SA to the set of all the candidate resources. In a case thatthe UE 102 executes the method in the example A, the UE 102 may initialize the set 5A to the set of all the Motaii candidate resources. In a case that the UE 102 executes the method in the example B, the UE 102 may initialize the set SA to the set of all the Motai3 candidate resources, In other words, in a case that the UE 102 executes the method in the example B, the UE 102 may not initialize the set 5A to the set of all the Motai2 candidate resources.

[0265] Additionally or alternatively, in some embodiments, the UE 102 may not perform resource exclusion based on the parameter D in the example B in the step 1. Instead, in the example B, the UE 102 may perform resource exclusion based on the parameter D in the step 4. Here, the UE 102 may determine to denote the total number of candidate resources by Motai2 in step 1. In step 4, in a case that the parameter D is provided (i.e., in a case that the information of RB sets where consistent LBT failure is detected is provided), the UE 102 may determine whether to exclude, from the Motai2 candidate resources, a candidate resource based on whether at least one of the LRBsetcontiguous RB sets of the candidate resource is an RB set indicated as consistent LBT failure by the parameter D. Same exclusion method illustrated in example B in the step 1 can be equally applied in the step 4. Upon exclusion, the total number of remaining candidate resources after exclusion can be denoted by Motais. The UE 102 may not initialize the set 5A to the set of all the Motai2 candidate resources but initialize the set 5A to the set of all the Motai3 candidate resources. The UE 102 may determine to denote the total number of candidate resources by Motai3. In a case that the parameter D is not provided (i.e., in a case that there is no information of RB sets where consistent LBT failure is detected is provided), the UE 102 initialize the set 5A to the set of all the Motai2 candidate resources.

[0266] Additionally or alternatively, in some embodiments, the UE 102 may not perform resource exclusion based on the parameter D in the example B in the step 1. Then, in example B, the resource exclusion may be performed in the step 4. Here, the UE 102 may determine to denote the total number of candidate resources by Motai2 in step 1. In step 4, the UE 102 may initialize the set 5A to the set of all the Motai2 candidate resources. Then, the UE 102 may perform resource exclusion based on the parameter D in the step 4. For the resource pool where interlace RB-based transmission is configured, in a case that the parameter D is provided (i.e., in a case that the informationof RB sets where consistent LBT failure is detected is provided), the UE 102 may determine whether to exclude, from the set SA, a candidate resource based on whether at least one of the LRBsetcontiguous RB sets of the candidate resource is an RB set indicated as consistent LBT failure by the parameter D. For the resource pool where contiguous RB-based transmission is configured, in a case that the parameter D is provided (i.e., in a case that the information of RB sets where consistent LBT failure is detected is provided), the UE 102 may determine whether to exclude, from the set 5A, a candidate resource based on whether at least one sub-channel of the LsubCH contiguous sub-channels of a candidate resource overlaps with at least 1 RB set indicated as consistent LBT failure by the parameter D or based on whether at least one sub-channel of the fsubcH contiguous sub-channels of a candidate resource includes at least 1 RB that belongs to an RB set indicated as consistent LBT failure by the parameter D. Same exclusion method illustrated in example B in the step 1 can be equally applied in the step 4. Upon exclusion, the total number of remaining candidate resources after exclusion can be denoted by Motai3- That is, the Motai2 in step 1 may be replaced by the A / total3.

[0267] Upon executing the step 4, the UE 102 may go to execute step 5.

[0268] Step 5 is a step of resource exclusion related to slot(s) in which the UE 102 has not monitored within the sensing window. As illustrated in step 2, within the sensing window, the UE 102 may not monitor slot(s) in which the UE 102 performs its own transmission due to half duplex operation. While other UEs could perform PSCCH / PSSCH transmissions in the slot(s) not monitored by the UE 102. For illustration, a slot in which the UE 102 has not monitored within the sensing window can be denoted as a slot m.

[0269] Given that the UE 102 cannot sense or obtain the sensing information from other UEs transmitted in the slot m, the UE 102 may assume that another UE transmits a SCI format 1-A in the slot m, i.e., the UE 102 may assume that a hypothetical SCI format 1-A is received in the slot m. The UE 102 may consider that any periodicity value (resource reservation period value) allowed by the higher layer parameter sl- ResourceReservePeriodList may be used by another UE to reserve resources for their periodic PSCCH / PSSCH transmissions. The parameter sl-ResourceReservePeriodList indicates a set of possible resource reservation period Prsvp_Rx allowed in the resourcepool in the unit of millisecond. The UE 102 may use each period Prsvp_RX inthe set to determine slot(s) corresponding to the slot m wherein the determined slot(s) are within the selection window. The UE 102 may exclude any candidate resource from the set SA if the candidate resource locates in the determined slot(s) corresponding to the slot m.

[0270] To be specific, the UE 102 may determine slot(s) corresponding to the slot m as slot(s) within the selection window. The parameter q is aninteger that takes values in the range 1 <= q <= Q. Here, if andelse Q is equal to 1. Tscaiis set to selectionwindow size Tz converted to units of millisecond. A resource reservation period verted to a period in logical slots as

[0271] Therefore, in step 5, the UE 102 may determine one or multiple slots corresponding to not monitored slot(s) (e.g., slot m) based on a set of resource reservation periods indicated by the parameter sl-ResourceReservePeriodList and slot position of not monitored slot(s). In the step 5, the UE 102 may determine to exclude any candidate resources from the set SA if the candidate resource overlaps with (or locates in) the determined one or multiple slots corresponding to not monitored slot(s) within the sensing window.

[0272] In step 5, after exclusion, the UE 102 may further check the number of candidate resources remaining in the set SA and compare the number to a certain proportion of total candidate resources. In a case that the number of candidate resources remaining in the set SA is equal to or larger than a certain proportion of the total candidate resources, the UE 102 may next execute the step 6. In a case that number of candidate resources remaining in the set SA is smaller than the certain proportion of the total candidate resources, the UE 102 may determine to initialize the set SA to the set of all the candidate resources as in step 4 and next execute the step 6. The number of the total candidate resource is denoted by Mtotal. The certain proportion of the total candidate resources, which can be denoted by X x Mtota[, is given based on the parameter sl-TxPercentageList. The sl-TxPercentageList indicates the value of X for the prioTX. To be specific, the sl-TxPercentageList indicates a list of X where each Xin the list corresponds to respective prioTX. The proportion is set by (pre-)configuration to X= 20%, 35%, or 50% for each priority prioTX.

[0273] In the example A, Mtotaican be replaced by the Mtotairthat denotes the total candidate resources. In the example B, Mtotalcan be replaced by the Mtotai3that denotes the total candidate resources. In a case that the UE 102 executes the method in the example A, the UE 102 may calculate the certain proportion of the total candidate resources by X x. In a case that the UE 102 executes the method in the example B, the UE 102 may calculate the certain proportion of the total candidate resources by X x Mtotat3.

[0274] Step 6 is a step of resource exclusion based on the received SCI information (SCI format 1-A) and sidelink measurement performed for the received SCI format 1- A. The UE 102 may measure the SL-RSRP for the received SCI format 1-A in the slot of the sensing window. The SL-RSRP may imply the level of interference which would be caused and experienced if the UE 102 performs transmission in them. The SL-RSRP can be (pre-)configurable measurement of either PSSCH-RSRP or PSCCH-RSRP.

[0275] In step 6, for those slots where SCI format 1-A is received, the UE 102 may perform resource exclusion based on PSCCH decoded and RSRP measured in those slots. For example, the UE 102 may receive a SCI format 1-A in the slot z. The 'Resource reservation period' field and the 'Priority' field in the received SCI format 1- A indicates the value Prsvp-RXand the value prioRX, respectively. The UE 102 may use determine a SL-RSRP threshold for combinationp]') as illustrated in step 3 where Pi is replaced by the indicated prioRXand pj is replaced by the prioTX, and set Th(pi,pj)' to the determined SL-RSRP threshold. In other words, the SL-RSRP threshold is at least a function of the priority p\ and pj where pi is the value of priority field in the received SCI format and pj is the priority of the transmission of the UE 102 selecting resources for the triggered procedure.

[0276] In the step 6, the UE may exclude any candidate resource from the set SA if the candidate resource overlaps with time and frequency resource of a reserved resource indicated by the received SCI format 1-A and the SL-RSRP measurement performed for the received SCI format 1-A is higher than the SL-RSRP threshold Th(pi, Pj'). If a candidate resource overlaps with time and frequency resource of a reserved resource indicated by the received SCI format 1-A and the SL-RSRP measurement performedfor the received SCI format 1-A is not higher than the SL-RSRP threshold Th(pt,pj'), the UE 102 may not exclude the candidate resource from the set SA- Thus, a higher priority transmission from the UE 102 can occupy resources which are reserved by other UEs with sufficiently low SL-RSRP and sufficiently lower-priority traffic.

[0277] Upon executing the step 6, the UE 102 may go to execute step 7.

[0278] Step 7 is a step of checking whether the number of candidate resources remaining in the set SA is smaller than X X Mtotai(i.e., the certain proportion of the total candidate resources within the selection window) and determining whether to increase Th(pi,pJ') by 3 dB for each priority combination (pj, p7). In the example A, Mtotai can be replaced by thethat denotes the total candidate resources. In the example B, Mtotaican be replaced by the MtotaV3that denotes the total candidate resources. In a case that the UE 102 executes the method in the example A, the UE 102 may calculate the certain proportion of the total candidate resources by X x Mtotau. In a case that the UE 102 executes the method in the example B, the UE 102 may calculate the certain proportion of the total candidate resources by X X Mtotal3.

[0279] In step 7, in a case that the number of candidate resources remaining in the set SA is equal to or larger than X x Mtotai, the UE 102 may determine to complete the procedure and report the set SA to higher layer. In a case that number of candidate resources remaining in the set SA is smaller than X X Mtotai, the UE 102 may determine to increase Th(pl, pj') by 3 dB for each priority combination (pt,Pp) and continue to execute steps of the procedure from step 4. That is, in this case, the UE 192 may repeat exclusion operation. Until the number of candidate resources remaining in the set SA is not smaller than X x Mtotai, the UE 102 may iteratively repeat the candidate resource exclusion operations.

[0280] In the present disclosure, whether to iteratively repeat the step of candidate exclusion (step 6) is determined at least based on the Mtotai. In other words, the Mtotalmay be at least used to determine whether to iteratively repeat the step of candidate exclusion (step 6). Specifically, in the example A, whether to iteratively repeat the step of candidate exclusion (step 6) is determined at least based on theor based on the X x Mtotan, In the example B, whether to iteratively repeat the step of candidate exclusion (step 6) is determined at least based on the Mtotai3or based on the X X ^totals •

[0281] In the present disclosure, as above-mentioned, there are 3 operations of resource exclusions. The first exclusion operation is the candidate resource exclusion step that is performed at least based on the information of consistent LBT failure provided by the parameter D. The second exclusion operation is the candidate resource exclusion step that is performed at least based on slot index(es) of not monitored slot(s) and periodicity values indicated by the parameter sl-ResourceReservePeriodList. The third exclusion operation is the candidate resource exclusion step that is performed at least based on the received SCI format 1-A and sidelink RSRP measurement for the received SCI format 1-A. The details of three exclusions operation have been explained above.

[0282] In some embodiments, to report candidate resources from a resource pool where either contiguous RB-based transmission and interlace RB-based transmission can be configured, the UE 102 may sequentially perform candidate resource exclusions in the order of the first exclusion operation, the second exclusion operation, and the third exclusion operation. The above illustration regarding defining the candidate resource can be applied. The UE 102 may firstly execute the first exclusion operation, secondly, execute the second exclusion operation, thirdly, execute the third exclusion operation. After executing the first exclusion operation, the UE 102 may not perform a check step, i.e,, to check whether the number of candidate resources remaining in the set SA is smaller than X · MtotaI. After executing the second exclusion operation, the UE 102 may perform the check step, i.e., to check whether the number of candidate resources remaining in the set SA is smaller than X · Mtotal. After executing the third exclusion operation, the UE 102 may perform the check step, i.e., to check whether the number of candidate resources remaining in the set SA is smaller than X • Mtotal.

[0283] In a case that the number of candidate resources remaining in the set SA is smaller than X · Mtotal, the UE 102 may iteratively repeat the second exclusion operation and / or the third exclusion operation. The UE 102 may not repeat the first exclusion operation regardless of if the number of candidate resources remaining in the set SA is smaller than X · Mtotal. The UE 102 may iteratively repeat the second exclusion operation and / or the third exclusion operation until the number of candidate resources remaining in the set SA is not smaller than X X Mtotat.

[0284] According to the exclusion order and the timing of performing check step, the candidate resources overlapping with RB set(s) indicated as consistent LBT failure can be excluded first and there is no need to retrieve these candidate resources for PSSCH transmission given that these candidate resources are not suitable for PSSCH transmission. On the other hand, the candidate resources excluded in the second exclusion operation and the third exclusion operation can be retrieved such that the amount of candidate resources reported to higher layer for resource selection can be guaranteed. Therefore, an efficient SL communication system is provided.

[0285] In the present disclosure, determination of a candidate resource for a procedure of sensing and resource selection in a resource pool may include one, more, or all of (I) determining the number of sub-channel(s) contained in the candidate resource, (II) determining sub-channel index(es) of sub-channel(s) contained in the candidate resource, (III) determining RB set index(es) of RB set(s) contained in the candidate resource, and (IV) determining slot index(es) where the candidate resource locates. Determination of a candidate resource for a resource pool where interlace RB- based transmission is applied includes the time and frequency resource. Specifically, determination of a candidate resource includes determining include one, more, or all of determining the number of sub-channel(s) contained in the candidate resource, determining sub-channel index(es) of sub-channel(s) contained in the candidate resource, determining RB set index(es) ofRB set(s) contained in the candidate resource, and determining slot index(es) where the candidate resource locates.

[0286] In the present disclosure, for the resource allocation of a PSSCH transmission, the time domain unit is a slot (a logical slot) while the frequency domain unit is a sub-channel in an RB set. In a resource pool, a PSSCH transmission or a PSSCH reception may be performed in one or more sub-channels in one or more RB sets in the frequency domain and in a set of one or more slots in the time domain.

[0287] Regarding the time resource allocation behavior, a parameter sl- MaxNumP er Reserve is used to indicate a maximum number of reserved PSCCH / PSSCH resources that can be indicated by the SCI format 1-A. The parameter sl-MaxNumP er Reserve is configured per resource pool. The value of the parameter sl- MaxNumPerReserve can be configured to 2 or 3, which means an SCI format 1-A can schedule up to 2 or 3 reserved resources for PSCCH / PSSCH transmission in the time domain.

[0288] The UE and / or the base station may determine the size of the time resource assignment field based on the value of the parameter sl-MaxNumP er Reserve. The UE and / or the base station may determine the size of the time resource assignment field as 5 bits when the value of the higher layer parameter sl-MaxNumP er Reserve is configured to 2 and may determine the size of the time resource assignment field as 9 bits when the value of the higher layer parameter sl-MaxNumP er Reserve is configured to 3.

[0289] The base station may use the time resource assignment field of the DCI format 3_0 to indicate a UE a set of one or more slots for PSSCH transmission. The UE may use the time resource assignment field of an SCI format 1 - A to determine a set of one or more slots for PSSCH transmission / reception associated with the SCI format 1-A. The one or more slots in the set can be contiguous or non-contiguous in the time domain. The number of the one or more slots in the set, N, may not be always same as the value of the parameter sl-MaxNumPerReserve. The number of the one or more slots, N, can be smaller than or equal to the value of the parameter sl-MaxNumPerReserve. The one or more slots in the set can be also referred to as the N actual resources for PSSCH transmission / reception.

[0290] Specifically, the time resource assignment field carries logical slot offset indications of / V=l or 2 actual resources when sl-MaxNumPerReserve is 2, and A=1 or 2 or 3 actual resources when sl-MaxNumPerReserve is 3, in a form of time RIV (TRIV) field which is determined as follows:

[0291] Herein, the value of the time resource assignment field can be referred to as a time resource indicator value (TRIV). The first resource among the N actual resource(s) is in the slot where the SCI format 1-A was received. For illustration, t\ denotes z'-th resource time offset in logical slots of a resource pool with respect to the first resource where for N-2, 1 <= t\ <= 31 ; and for N=3, 1 <= t\ <= 30, t\ < ti <= 31 . For example, when t\ = 1, it means the second resource is assigned in a slot adjacent to the first resource.

[0292] According to the above formula for TRIV, when the parameter sl- MaxNumP er Reserve is configured to 2, the size of the time resource assignment is 5 bits where 1 codepoint (i.e., TRIV = 0) indicates no second resource to be scheduled by the SCI format, i.e., the SCI format schedules the AM actual resource (the first resource) for PSSCH transmission, and each of the remaining 31 codepoints indicate a corresponding logical slot offset indication for the scheduled second resource with respect to the first resource.

[0293] Likewise, when the parameter sl-MaxNumP er Reserve is configured to 3, the size of the time resource assignment is 9 bits where 1 codepoint (i.e., TRIV = 0) indicates no second and third resources to be scheduled by the SCI format; 31 codepoints (i.e., 1 <= TRIV <= 31) indicate that there is a second resource scheduled by the SCI format but no third resource scheduled by the SCI format wherein each of the 31 codepoints indicates a corresponding logical slot offset indication for the second resource with respect to the first resource; a part of the remaining codepoints indicate there are both a second resource and a third resource scheduled by the SCI format, wherein one of the part of the remaining codepoints may indicate corresponding logical slot offset indications for the second resource and the third resource with respect to the first resource.

[0294] The UE 102 and / or the base station 160 may determine the size of the frequency resource assignment field based on whether or how the parameter A is configured or not. Specifically, in the first case, the UE may determine the size of the frequency resource assignment field as when the value ofthe parameter sl-MaxNumPerReserve is configured to 2, and may determine the size of the frequency resource assignment field aswhen the value of the parameter sl-MaxNumP er Reserve is configured to 3. Here, |\4] denotes the ceiling operation which is to output a smallest integer not less than A. The ^ subchannel isthe number of the one or more sub-channels included in a resource pool, which is indicated by the parameter sl-NumSub channel included in a configuration of the resource pool. Each sub-channel includes a number of contiguous RBs in the frequency domain. According to the formulas for determining the size of frequency resource assignment field, the UE may determine the size of the frequency resource assignment field based on the parameter sl-MaxNumP er Reserve and the parameter sl- NumSubchannel, The size determination herein for the frequency resource assignment field may be applied to a resource pool which is configured with the contiguous RB- based transmission.

[0295] In the second case, the UE 102 and / or the base station 160 may determine the size of the frequency resource assignment field as (X+Y) bits where the X MSBs provide the RB set allocation and the Y LSBs provide the sub-channel allocation. The value of X is determined as when the value of the parametersl-MaxNumP er Reserve is configured to 2, or is determined as when the value of the parameter sl-MaxNumP er Reserve is configured to 3. The value of Y is determined as when the value of the parameter sl-MaxNumPerReserveis configured to 2, or is determined asthe value of the parameter sl-MaxNumP er Reserve is configured to 3.

[0296] The frequency resource assignment field provides a frequency RIV (FRIV) in the first case. That is, the value of the frequency resource assignment field can be referred to as a frequency resource indicator value (FRIV). The frequency resource assignment field indicates the number of contiguously allocated sub-channels for each of the N actual resources and the starting sub-channel indexes of the N actual resources except the first resource.

[0297] To be specific, the frequency resource for PSSCH transmission can be determined from the FRIV as follows. If the sl-MaxNumPerReserve is 2, then FRIV — 0 • If the sl-MaxNumPerReserve is 3, then) Here, the number of contiguously allocated sub-channels can be denoted by hSubCH where the LsubCH— 1- In the frequency domain, each resource among the N actual resources includes the LsubCHsub-channel(s). The starting sub-channel indexes for the first resource among the N actual resources can be denoted aswhere the sub-channel with index n is a sub-channel on which the lowest PRB of theassociated PSCCH is transmitted. Moreover, the sub-channel with index nss^cH 0is also a lowest sub-channel for the sidelink (PSSCH) transmission scheduled by the SCI format 1-A. Additionally,denotes the starting sub-channel index for the second resource, anddenotes the starting sub-channel index for the third resource.

[0298] In the second case, the frequency resource assignment field provides two frequency RIVs (FRIVs) where X MSBs of the frequency resource assignment field provide a FRIV_RBset, and Y LSBs of the frequency resource assignment field provide a FRIV_sub channel.

[0299] The FRIV_RBset is used to determine a number of contiguously allocated RB sets for each of the N actual resources and the starting RB set indexes of the N actual resources except the first resource. To be specific, the RB set allocation for PSSCH transmission can be determined from the FRIVJRBset as follows. If the sl- MaxNumPerReserve is 2, then 0-lithe sl-MaxNumPerReserve is 3, then FRIV_RBset = n^sgt r+ n^set? ■ (IV^3.set+e . Here, the number of contiguously allocated RB sets can be denoted by LRBSetwhere the hRBset — !■ Inthe frequency domain, each resource among the N actual resources includes the LRBSetRB set(s). The starting RB set index for the first resource among the N actual resources can be denoted as n^g^.o where the RB set with indexis an RB set on which the lowest PRB of the associated PSCCH is transmitted., denotes the starting RB set index for the second resource, and z denotes the starting RB set index for the third resource.

[0300] The F R1V _subchannel indicates the number of contiguously allocated subchannels for each of the N actual resources in an RB set and the starting sub-channel indexes of the N actual resources except the first resource. To be specific, the sub-channel allocation for PSSCH transmission can be determined from the FRIV -Subchannel as follows. If the sl-MaxNumP er Reserve is 2, then. If the sl-MaxNumP er Reserve is 3, then~Here, the number of contiguously allocated sub-channels in an RB set can be denoted by FsubCH, RBset where the- In the frequency domain, each resource among the N actual resources includes the LSubCH, RBset sub-channel(s) in each allocated RB set. The total number of sub-channels included in each resource is equal to LsubCH = ^subCH, RBsetx^RBset-

[0301] The starting sub-channel indexes for the first resource among the N actual resources in each allocated RB set can be denoted as n^bcHi0. The sub-channel with index'nthe RB set with index’s asub-channel on which the lowest PRB of the associated PSCCH is transmitted. That is, the UE 102 may transmit PSCCH with SCI format 1-A in the sub-channel with index nss^H,o >nthe RB set with index- Additionally,1denotes the starting sub-channel index for the second resource in each allocated RB set, denotes the starting sub-channel indexfor the third resource in each allocated RB set.

[0302] In mode 1, after determining the frequency resource for PSCCH / PSSCH transmission for a UE, the base station may generate some or all of the first field, the second field, the frequency resource assignment (i.e., a FRIV) field in the DCI format 3_0 to indicate the UE the determined frequency resource for PSCCH / PSSCH transmission. The UE (i.e., a TX UE) may transmit a SCI format 1 -A including the frequency resource assignment generated by the base station and transmit the PSCCH / PSSCH on the determined frequency resource.

[0303] Upon detection the SCI format 1-A, a RX UE can determine the frequency resource based on the frequency resource assignment field and the frequency location where the SCI format 1-A is detected.

[0304] Figure 11 illustrates various components that may be utilized in a UE 1102. The UE 1102 (UE 102) described in connection with Figure 11 may be implemented in accordance with the UE 102 described in connection with Figure 1. The UE 1102 includes a processor 1181 that controls operation of the UE 1102. The processor 1181may also be referred to as a central processing unit (CPU). Memory 1187, which may include read-only memory (ROM), random access memory (RAM), a combination of the two or any type of device that may store information, provides instructions 1183a and data 1185a to the processor 1181. A portion of the memory 1187 may also include non-volatile random access memory (NVRAM). Instructions 1183b and data 1185b may also reside in the processor 1181. Instructions 1183b and / or data 1185b loaded into the processor 1181 may also include instructions 1183a and / or data 1185a from memory 1187 that were loaded for execution or processing by the processor 1181. The instructions 1183b may be executed by the processor 1181 to implement one or more of the methods described above.

[0305] The UE 1102 may also include a housing that contains one or more transmitters 1158 and one or more receivers 1120 to allow transmission and reception of data. The transmitter(s) 1158 and receiver(s) 1120 may be combined into one or more transceivers 1118. One or more antennas 1122a-n are attached to the housing and electrically coupled to the transceiver 1118.

[0306] The various components of the UE 1102 are coupled together by a bus system 1189, which may include a power bus, a control signal bus and a status signal bus, in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in Figure 11 as the bus system 1189. The UE 1102 may also include a digital signal processor (DSP) 1191 for use in processing signals. The UE 1102 may also include a communications interface 1193 that provides user access to the functions of the UE 1102. The UE 1102 illustrated in Figure 11 is a functional block diagram rather than a listing of specific components.

[0307] Figure 12 illustrates various components that may be utilized in a base station 1260. The base station 1260 described in connection with Figure 12 may be implemented in accordance with the base station 160 described in connection with Figure 1. The base station 1260 includes a processor 1281 that controls operation ofthe base station 1260. The processor 1281 may also be referred to as a central processing unit (CPU). Memory 1287, which may include read-only memory (ROM), random access memory (RAM),, a combination of the two or any type of device that may store information, provides instructions 1283a and data 1285a to the processor 1281. A portion of the memory 1287 may also include non-volatile random access memory (NVRAM). Instructions 1283b and data 1285b may also reside in the processor 1281.Instructions 1283b and / or data 1285b loaded into the processor 1281 may also include instructions 1283 a and / or data 1285a from memory 1287 that were loaded for execution or processing by the processor 1281. The instructions 1283b may be executed by the processor 1281 to implement one or more of the methods 300 described above.

[0308] The base station 1260 may also include a housing that contains one or more transmitters 1217 and one or more receivers 1278 to allow transmission and reception of data. The transmitter(s) 1217 and receiver(s) 1278 may be combined into one or more transceivers 1276. One or more antennas 1280a-n are attached to the housing and electrically coupled to the transceiver 1276.

[0309] The various components of the base station 1260 are coupled together by a bus system 1289, which may include a power bus, a control signal bus and a status signal bus, in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in Figure 12 as the bus system 1289. The base station 1260 may also include a digital signal processor (DSP) 1291 for use in processing signals. The base station 1260 may also include a communications interface 1293 that provides user access to the functions of the base station 1260. The base station 1260 illustrated in Figure 12 is a functional block diagram rather than a listing of specific components.

[0310] The term “computer-readable medium” refers to any available medium that can be accessed by a computer or a processor. The term “computer-readable medium,” as used herein, may denote a computer- and / or processor-readable medium that is non- transitory and tangible. By way of example, and not limitation, a computer-readable or processor-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer or processor. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

[0311] It should be noted that one or more of the methods described herein may be implemented in and / or performed using hardware. For example, one or more of the methods described herein may be implemented in and / or realized using circuitry, a chipset, an application-specific integrated circuit (ASIC), a large-scale integrated circuit (LSI) or integrated circuit, etc.

[0312] Each of the methods disclosed herein comprises one or more steps or actions for achieving the described method. The method steps and / or actions may be interchanged with one another and / or combined into a single step without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0313] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the systems, methods and apparatus described herein without departing from the scope of the claims.

Claims

[CLAIMS]1 . A user equipment (UE), comprising: reception unit configured to receive, from a higher layer of the UE, a first parameter and a second parameter for a PSSCH transmission in a resource pool, the first parameter indicating a number of sub-channels, the second parameter indicating a number of RB sets, ZRBSET; and control unit configured to determine candidate resources within a time interval for the PSSCH transmission, wherein a candidate resource is identified by a symbol Rr,x,y> wherein a candidate resource Rr,x,y is defined as a set of one or more contiguous subchannels starting from a sub-channel with index x in a slot with index y in the LRBSET contiguous RB sets starting from an RB set with index r, and the number of one or more contiguous sub-channels is determined at least based on the first parameter.

2. The UE according to the claim 1 : wherein interlace RB-based transmission is configured for the resource pool.

3. A communication method performed by a user equipment (UE), comprising: receiving, from a higher layer of the UE, a first parameter and a second parameter for a PSSCH transmission in a resource pool, the first parameter indicating a number of sub-channels, the second parameter indicating a number of RB sets, ERBSET; and determining candidate resources within a time interval for the PSSCH transmission, wherein a candidate resource Rr,x,y is defined as a set of one or more contiguous subchannels starting from a sub-channel with index x in a slot with index y in the ZRBSET contiguous RB sets starting from an RB set with index r, and the number of one or more contiguous sub-channels is determined at least based on the first parameter.

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