Channel structure of sidelink synchronization signal block in listen-before-talk operation

Abstract

Systems, methods, apparatuses, or computer readable media for performing listen before talk (LBT) operations in sidelink communications are provided. A wireless communication device can perform an LBT operation with respect to a sidelink synchronization signal block (S-SSB), the S-SSB having a first portion and a second portion. The first portion can repeat one or more symbols of the second portion according to a configuration of the second portion. The wireless communication device can determine a failure of the LBT operation at a first point of the S-SSB. The wireless communication device can determine a success of the LBT operation at a second point of the S-SSB, the second point being after the first point. In response to the success, the wireless communication device can transmit at least a portion of the S-SSB, the portion mapping to one or more time domain resources starting from the second point.

Description

Technical Field

[0001] This disclosure generally relates to wireless communications, including but not limited to systems and methods for performing Listen-Before-Speak (LBT) operations in secondary link communications. Background Technology

[0002] The standards organization 3GPP is currently specifying a new radio interface called 5G New Radio (5GNR) and a next-generation packet core network (NG-CN or NGC). 5G NR will have three main components: 5G Access Network (5G-AN), 5G Core Network (5GC), and User Equipment (UE). To facilitate the implementation of different data services and requirements, the elements of 5GC (also known as network functions) have been simplified, with some elements being software-based so that they can be adapted as needed. Summary of the Invention

[0003] The exemplary embodiments disclosed herein are intended to address problems related to one or more issues arising in the prior art and provide additional features that will become apparent from the following detailed description taken in conjunction with the accompanying drawings. Exemplary systems, methods, apparatuses, and computer program products are disclosed herein according to various embodiments. However, it should be understood that these embodiments are presented by way of example and are not restrictive, and various modifications to the disclosed embodiments will be apparent to those skilled in the art who read this disclosure, while remaining within the scope of this disclosure.

[0004] At least one aspect relates to a system, method, apparatus, or computer-readable medium for performing a Listen-Before-Speak (LBT) operation in secondary link communication. A wireless communication device can perform an LBT operation with respect to a secondary link synchronization signal block (S-SSB), the S-SSB having a first portion and a second portion. The first portion can repeat one or more symbols of the second portion according to a configuration of the second portion. The wireless communication device can determine a failure of the LBT operation at a first point of the S-SSB. The wireless communication device can determine a success of the LBT operation at a second point of the S-SSB, the second point being after the first point. In response to the success, the wireless communication device can transmit at least a portion of the S-SSB, which is mapped to one or more time-domain resources starting from the second point.

[0005] In some embodiments, the wireless communication device may determine a second failure of the LBT operation at a third point in the S-SSB, the third point being after the first point. In some embodiments, in response to the second failure, the wireless communication device may transmit a second portion of the S-SSB, the second portion having one or more second time-domain resources after the first point. In some embodiments, in response to success at the second point, the wireless communication device may discard the second portion of the S-SSB, the second portion having one or more second time-domain resources starting from the second point. In some embodiments, the wireless communication device may determine a success of the LBT operation at a third point in the S-SSB, the third point being after the first point. In some embodiments, in response to success at the third point, the wireless communication device may transmit a second portion of the S-SSB, the second portion having one or more second time-domain resources starting from the third point.

[0006] In some embodiments, the first portion of the S-SSB may repeat one or more symbols of one of several types, which are among several types used for secondary link synchronization. These types may include at least one of the Secondary Link Primary Synchronization Signal (S-PSS) or the Secondary Link Secondary Synchronization Signal (S-SSS). In some embodiments, the first portion of the S-SSB may repeat one or more symbols of the second portion, depending on the configuration of the first portion. In some embodiments, the first portion of the S-SSB may repeat one or more symbols of the second portion, starting from an initial symbol index and ending at a terminating symbol index, where the terminating symbol index precedes the initial symbol of the Physical Secondary Link Broadcast Channel (PSBCH).

[0007] In some embodiments, S-SSB transmission may be applied only to the second S-SSB set. In some embodiments, the second S-SSB set may be located on a time slot not mapped by the resource pool association bitmap. In some embodiments, the entire first S-SSB set may be transmitted when the second point corresponds to the initial symbol index. In some embodiments, the first S-SSB set is located on a time slot mapped by the resource pool association bitmap. In some embodiments, on the time slot for transmitting / configuring / predefining the first S-SSB set, only a single starting point of the PSSCH / PSCCH may be configured or predefined / used.

[0008] In some embodiments, in response to success at a second point corresponding to the initial symbol index, the wireless communication device may transmit the entire S-SSB, which is mapped to one or more time-domain resources. In some embodiments, the wireless communication device may, in response to (i) LBT failure at a first point corresponding to the initial symbol index and (ii) LBT success at a second point corresponding to at least one index following the initial symbol index, discard at least one initial symbol corresponding to the initial symbol index during transmission. In some embodiments, in response to (i) LBT failure at the first point and (ii) success at a second point corresponding to a multiple of 9 μs or 16 μs following the first point, the wireless communication device may discard at least some time-domain resources during transmission, these resources being multiples of 9 μs or 16 μs following the first point.

[0009] In some embodiments, based on at least one of the number of symbols used for mapping, subcarrier spacing, number of RBs, or number of interleavings, the first portion of an S-SSB may repeat a repetition range corresponding to one or more symbols in the second portion. In some embodiments, the first number of S-SSBs not belonging to the resource pool and the second number of S-SSBs belonging to the resource pool may be configured or predefined, respectively. In some embodiments, the mapping ratio between the first number of S-SSBs not belonging to the resource pool and the second number of S-SSBs belonging to the resource pool may be configured or predefined.

[0010] In some embodiments, the first number defined within a set of resource blocks (RBs) or a bandwidth portion (BWP) may be different from or the same as the second number of symbols. In some embodiments, the first and second points may be identified from a plurality of candidate starting points for LBT operation. Each candidate starting point may be defined within at least one of the set of resource blocks (RBs) or a bandwidth portion (BWP).

[0011] In some embodiments, the first number of candidate start points for LBT operations in the first RB set may be less than the second number of candidate start points for LBT operations in the second RB set. In some embodiments, the first position of at least one first candidate start point for LBT operations in the first RB set may be earlier than the second position of at least one second candidate start point for LBT operations in the second RB set. In some embodiments, a larger number of candidate start points or an earlier position of candidate start points may correspond to a higher priority of S-SSB or fewer LBT failures. S-SSBs are located on time slots not mapped by the resource pool association bitmap, or on time slots mapped by the resource pool association bitmap. In some embodiments, the S-SSBs located on time slots not mapped by the bitmap are associated with SSBs located on time slots mapped by the bitmap. Attached Figure Description

[0012] Various exemplary embodiments of this solution are described in detail below with reference to the accompanying drawings. The drawings are provided for illustrative purposes only, depicting only exemplary embodiments of this solution to facilitate the reader's understanding. Therefore, the drawings should not be considered as limitations on the breadth, scope, or applicability of this solution. It should be noted that these drawings are not necessarily drawn to scale for clarity and ease of explanation.

[0013] Figure 1 An example cellular communication network is shown that can implement the techniques disclosed herein according to embodiments of this disclosure;

[0014] Figure 2 Block diagrams of example base station and user equipment apparatuses according to some embodiments of the present disclosure are shown;

[0015] Figure 3 A block diagram of a network architecture for secondary link communication according to an illustrative embodiment is shown;

[0016] Figure 4 A block diagram of the channel structure of the sublink synchronization signal block (S-SSB) according to an illustrative embodiment is shown;

[0017] Figure 5 A block diagram of resource elements in a sublink synchronization signal block (S-SSB) according to an illustrative embodiment is shown;

[0018] Figure 6A A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, the repetition range of which includes a single type of synchronization signal occupying the entire frequency range;

[0019] Figure 6B A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, the repetition range of which includes interleaved (e.g., the synchronization signals on all symbols within the repetition range are different), multiple types of synchronization signals occupying different frequency range segments, and a physical secondary link broadcast channel (PSBCH).

[0020] Figure 6C A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, the repetition range of which includes non-interleaved (e.g., the synchronization signal is the same on all symbols within the repetition range), a single type of synchronization signal occupying different frequency range segments, and a physical secondary link broadcast channel (PSBCH).

[0021] Figure 6DA block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, the repetition range of which includes interleaved (e.g., the synchronization signals on all symbols in the repetition range are different), multiple types of synchronization signals occupying the entire frequency range, and a physical secondary link broadcast channel (PSBCH).

[0022] Figure 7A A block diagram of a secondary link synchronization signal block (S-SSB) is shown according to an illustrative embodiment, the first part of which repeats the second part, which contains various types of synchronization signals and physical secondary link broadcast channels (PSBCH) occupying different frequency bands and symbols.

[0023] Figure 7B A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, wherein the first part repeats the single type of synchronization signal of the second part, which occupies the entire frequency band;

[0024] Figure 7C A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, the first part of which repeats the single type of synchronization signal and PSBCH of the second part, which occupy the entire frequency band;

[0025] Figure 8 A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, in which the symbols of the second part are repeated using symbol indexes in the first part;

[0026] Figure 9A A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, which discards the first symbol of the first part and has a second part of multiple types of synchronization signals and physical secondary link broadcast channels (PSBCH) occupying different frequency segments and symbols.

[0027] Figure 9B A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, which discards the first symbol of the first portion and has a second portion of a single type of synchronization signal occupying the entire frequency band;

[0028] Figure 9C A block diagram of a secondary link synchronization signal block (S-SSB) according to an illustrative embodiment is shown, which discards the first symbol of a first portion and has a second portion containing multiple types of synchronization signals occupying the entire frequency band; and

[0029] Figure 10 A flowchart is shown of a method for performing a Listen-Before-Speak (LBT) operation in secondary link communication according to an illustrative embodiment. Detailed Implementation

[0030] Various exemplary embodiments of this solution will now be described with reference to the accompanying drawings to enable those skilled in the art to manufacture and use this solution. Those skilled in the art will understand that after reading this disclosure, various changes or modifications can be made to the examples described herein without departing from the scope of this solution. Therefore, this solution is not limited to the exemplary embodiments and applications described and illustrated herein. Furthermore, the specific order or hierarchy of steps in the methods disclosed herein is merely an example method. Based on design preferences, the specific order or hierarchy of steps in the disclosed methods or processes can be rearranged while still remaining within the scope of this solution. Therefore, those skilled in the art will understand that the methods and techniques disclosed herein present various steps or actions in an exemplary order, and this solution is not limited to the specific order or hierarchy presented, unless otherwise expressly stated.

[0031] Mobile communication technology and environment

[0032] Figure 1 An example wireless communication network and / or system 100 according to an embodiment of this disclosure is illustrated, in which the techniques disclosed herein can be implemented. In the following discussion, wireless communication network 100 can be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as "network 100". This example network 100 includes seven base stations 102 (hereinafter referred to as "BS 102"; also referred to as wireless communication nodes) and user equipment devices 104 (hereinafter referred to as "UE 104"; also referred to as wireless communication devices), which can communicate with each other via communication link 110 (e.g., a wireless communication channel), and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. Figure 1 In this context, BS 102 and UE 104 are contained within their respective geographical boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating within its allocated bandwidth to provide sufficient radio coverage for its intended users.

[0033] For example, BS 102 can operate with allocated channel transmission bandwidth to provide sufficient coverage to UE 104. BS 102 and UE 104 can communicate via downlink radio frame 118 and uplink radio frame 124, respectively. Each radio frame 118 / 124 can be further divided into subframes 120 / 127, which may include data symbols 122 / 128. In this disclosure, BS 102 and UE 104 are described herein as non-limiting examples of "communication nodes" that, in general, can practice the methods disclosed herein. According to various embodiments of this scheme, such communication nodes may be able to perform wireless and / or wired communication.

[0034] Figure 2 FIG. 2 illustrates a block diagram of an exemplary wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) in accordance with some embodiments of the present solution. System 200 may include components and elements configured to support known or conventional operating characteristics, which need not be described in detail herein. In an illustrative embodiment, system 200 may be used to transmit (e.g., send and receive) data symbols in a wireless communication environment (e.g., Figure 1 wireless communication environment 100) as described above.

[0035] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user equipment device 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled and interconnected with each other via a data communication bus 220 as needed. UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled and interconnected with each other via a data communication bus 240 as needed. BS 202 communicates with UE 204 via a communication channel 250, which may be any wireless channel or other medium suitable for transmitting the data described herein.

[0036] Those of ordinary skill in the art will understand that system 200 may also include any number of modules other than Figure 2 the modules shown. Those skilled in the art will understand that the various illustrative blocks, modules, circuits, and processing logics described in connection with the embodiments disclosed herein may be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, the various illustrative components, blocks, modules, circuits, and steps are generally described in terms of their functionality. Whether these functions are implemented as hardware, firmware, or software may depend on the particular application and the design constraints imposed on the overall system. Persons familiar with the concepts described herein may implement these functions in a suitable manner for each particular application, but these implementation decisions should not be construed as limiting the scope of the present disclosure.

[0037] According to some embodiments, UE transceiver 230, which may be referred to herein as "uplink" transceiver 230, includes a radio frequency (RF) transmitter and an RF receiver, each including circuitry coupled to antenna 232. A duplex switch (not shown) can alternately couple the uplink transmitter or receiver to the uplink antenna in a time-division duplex manner. Similarly, according to some embodiments, BS transceiver 210, which may be referred to herein as "downlink" transceiver 210, includes an RF transmitter and an RF receiver, each including circuitry coupled to antenna 212. A downlink duplex switch can alternately couple the downlink transmitter or receiver to downlink antenna 212 in a time-division duplex manner. The operation of the two transceiver modules 210 and 230 can be coordinated in a timely manner such that the uplink receiver circuitry is coupled to uplink antenna 232 to receive transmissions on wireless transmission link 250, while the downlink transmitter is coupled to downlink antenna 212. Conversely, the operation of the two transceivers 210 and 230 can be coordinated in a timely manner, such that the downlink receiver is coupled to the downlink antenna 212 to receive transmissions on the wireless transmission link 250, while the uplink transmitter is coupled to the uplink antenna 232. In some embodiments, there is tight time synchronization with minimal guard time between changes in duplex direction.

[0038] UE transceiver 230 and base transceiver 210 are configured to communicate via wireless data communication link 250 and cooperate with appropriately configured RF antenna arrangements 212 / 232, which may support specific wireless communication protocols and modulation schemes. In some illustrative embodiments, UE transceiver 230 and base transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it should be understood that this disclosure is not necessarily limited to specific standards and related protocols in application. Rather, UE transceiver 230 and base transceiver 210 may be configured to support alternative or additional wireless data communication protocols, including future standards or variations thereof.

[0039] According to various embodiments, BS 202 may be, for example, an evolved Node B (eNB), a serving eNB, a target eNB, a nanocell, or a picocell. In some embodiments, UE 204 may be embodied in various types of user equipment, such as mobile phones, smartphones, personal digital assistants (PDAs), tablets, laptops, wearable computing devices, etc. Processor modules 214 and 236 may be implemented or realized using a general-purpose processor, content-addressable memory, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof to perform the functions described herein. In this way, the processor may be implemented as a microprocessor, a controller, a microcontroller, a state machine, etc. The processor may also be implemented as a combination of computing devices, such as a combination of a digital signal processor and a microprocessor, multiple microprocessors, a combination of one or more microprocessors with a digital signal processor core, or any other such configuration.

[0040] Furthermore, the steps of the methods or algorithms described in relation to the embodiments disclosed herein can be directly embodied in hardware, firmware, software modules executed by processor modules 214 and 236 respectively, or any actual combination thereof. Memory modules 216 and 234 can be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 can be coupled to processor modules 210 and 230 respectively, such that processor modules 210 and 230 can read information from and write information to memory modules 216 and 234 respectively. Memory modules 216 and 234 can also be integrated into their respective processor modules 210 and 230. In some embodiments, memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during instructions to be executed by processor modules 210 and 230 respectively. Memory modules 216 and 234 may each include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0041] Network communication module 218 typically represents the hardware, software, firmware, processing logic, and / or other components of base station 202 that enable bidirectional communication between base station transceiver 210 and other network components and communication nodes configured to communicate with base station 202. For example, network communication module 218 may be configured to support Internet or WiMAX traffic. In a typical deployment, but not limited to, network communication module 218 provides an 802.3 Ethernet interface, enabling base station transceiver 210 to communicate with legacy Ethernet-based computer networks. In this way, network communication module 218 may include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). The terms “configured for,” “configured to,” and variations thereof, used herein in connection with a particular operation or function, refer to devices, components, circuits, structures, machines, signals, etc., that are physically constructed, programmed, formatted, and / or arranged to perform a particular operation or function.

[0042] The Open Systems Interconnection (OSI) model (referred to as the "OSI model" in this document) is a conceptual and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) for interconnection and communication with other systems. The model is divided into seven sub-components or layers, each representing a set of conceptual services provided to its upper and lower layers. The OSI model also defines logical networks and efficiently describes computer packet transmission using different layer protocols. The OSI model can also be referred to as the seven-layer OSI model or the seven-layer model. In some embodiments, the first layer may be the physical layer. In some embodiments, the second layer may be the Media Access Control (MAC) layer. In some embodiments, the third layer may be the Radio Link Control (RLC) layer. In some embodiments, the fourth layer may be the Packet Data Convergence Protocol (PDCP) layer. In some embodiments, the fifth layer may be the Radio Resource Control (RRC) layer. In some embodiments, the sixth layer may be the Non-Access Stratum (NAS) layer or the Internet Protocol (IP) layer, and the seventh layer is other layers.

[0043] Figure 3A schematic diagram of a network architecture for secondary link communication is shown. For example, as shown, the network may include a base station (BS), a relay (node) (e.g., a header UE), and two UEs, UE1 and UE2. For example, UE1 may be a mobile phone, while UE2 may be a smart gadget (e.g., smart glasses). In some embodiments, UE1 and / or UE2 may be Internet of Things (IoT) devices. UE1 and UE2 may communicate with the BS directly or via the relay. Based on secondary link (SL) scheduling received from the BS, the relay, UE1, and UE2 may communicate with each other. Communication between any two relays, UE1, and UE2 can be referred to as secondary link communication. SL communication may take the form of unicast, multicast, or broadcast. Furthermore, UE2 may communicate with the BS / relay via UE1. That is, UE1 can act as a UE / mobile relay.

[0044] 2. Systems and methods for performing "listen-before-speak" operations in secondary link communication.

[0045] Now for reference Figure 4 The diagram illustrates a block diagram of the channel structure for a Sublink Synchronization Signal Block (S-SSB). For S-SSB transmission in sublink operation on unlicensed spectrum, LBT failure can lead to the failure of the Physical Sublink Broadcast Channel (PSBCH) and synchronization signal transmission, thus degrading the synchronization and communication performance of the sublink. LBT failure may be more likely to occur compared to WiFi, which can transmit at any time. This may be because, when LBT operation senses idleness for a given duration prior to this moment, it may only initiate S-SSB transmission at the slot boundary starting from the PSBCH at symbol 0, such as... Figure 3 As shown.

[0046] To increase S-SSB channel access opportunities, a method can be proposed to increase the number of candidate S-SSB start points (e.g., within a time slot). This way, when LBT operation occurs at a specified initial start point... a If the process fails, you can start from the beginning. b Perform the LBT operation. a and b The time interval can be 9 μs, 16 μs, or an integer multiple of the sign. If the LBT operation is at a candidate start point... b Successful, without transmitting at the initial starting point. a and b Mapped signals or channels between, or transmitted only in b S-SSB can still successfully access the channel after the mapping signal or channel.

[0047] For S-SSB transmissions involving secondary link operations on unlicensed spectrum, some transmission slots can be excluded from the candidate pool according to the following procedure. Under the first procedure, the set of slots that may belong to the secondary link resource pool can be represented as follows: ,in:

[0048] ,

[0049] The time slot index can be time slot 0 relative to the radio frame corresponding to System Frame Number (SFN) 0 or Direct Frame Number (DFN) 0 of the serving cell. This is in addition to the option to configure the S-SS / PSBCH block (S-SSB). In addition to the one time slot, the set can include all other time slots.

[0050] For secondary link operations on unlicensed spectrum, there may be two types of S-SSB slots. According to the procedure described above, one type of S-SSB slot can be excluded from the SL (secondary link) resource pool. This type of S-SSB slot may therefore not be mapped by the resource pool association bitmap.

[0051] Another type of S-SSB slot is configured or predefined in a set of slots that may belong to the secondary link resource pool (e.g., not to the set to be excluded). This type of S-SSB slot can therefore be mapped by a resource pool association bitmap. However, these S-SSB slots may reside within a set of slots allocated to the secondary link resource pool and correspond to specific slots. Its corresponding ,in .

[0052] In the second procedure, the User Equipment (UE) can determine the set of time slots allocated to the secondary link resource pool as follows. A resource pool association bitmap can be used. The length of the bitmap It can be configured at a higher level. If... ,in Then time slot It belongs to this set. Time slots within the set can be reindexed, allowing the remaining time slots to... subscript i Continuous ,in It can be the number of remaining time slots in the set.

[0053] The UE can determine the set of resource blocks allocated to the secondary link resource pool. This determination is made by... N PRB A resource block pool consisting of physical resource blocks (PRBs). Sub-channel m ( m= 0, 1, ..., numSubchannel - 1) can include a set A contiguous resource block, with physical resource block number [ ]. , ,in and Each is determined by higher-level parameters sl- StartRB-Subchannel and sl-SubchannelSize Given. The UE may not need to use the last one in the resource pool. mod One PRB.

[0054] A. Symbol configuration in the secondary link synchronization signal block (S-SSB)

[0055] In conjunction with the Listen-Before-Speak (LBT) operation, the symbol configuration in the Secondary Link Synchronization Signal Block (S-SSB) can be as follows: The repetition range for carrying repeated Primary Synchronization Signals (PSS), Secondary Synchronization Signals (SSS), or Physical Secondary Link Broadcast Channels (PSBCH) can be predefined or configured. The predefined or configured frequency resources can be occupied by some or all of the S-PSS / S-SSS / PSBCH. Configuration can include configurations made via gNB, Radio Resource Control (RRC), system information, or pre-configuration.

[0056] Now for reference Figure 5 This diagram depicts the resource elements within a Sublink Synchronization Signal Block (S-SSB). For example, a Sublink PSS (S-PSS) or Sublink SSS (S-SSS) of length 127 can occupy up to 11 resource blocks (RBs), with resource elements (REs) {0, 1, 129, 130, 131} representing protection REs set to 0. The PSBCH can occupy a configured or predefined frequency range (e.g., the number of interleaving intervals). The PSBCH cannot be mapped to intra-cell protection RBs or REs.

[0057] Now for reference Figure 6A The diagram illustrates a block diagram of a Sublink Synchronization Signal Block (S-SSB), whose repetition range contains a single type of synchronization signal occupying the entire frequency range. The S-SSB can be mapped from a starting point (e.g., the first symbol of a time slot) to the end of the time slot. An S-SSB can comprise two parts. The first part can be mapped from a symbol... Beginning, and including The second part can be derived from the symbols. Beginning, and including A symbol. It can take values ​​within the range {0,1,2,3,4,5,6,7}.

[0058] In the first part, the S-PSS or S-SSS may be mapped to a configured or predefined frequency range (e.g., the number of interleaving symbols if configured or predefined). An S-PSS or S-SSS of length 127 may occupy no more than 11 RBs (132 REs), where RE{0, 1, 129, 130, 131} is set to 0. The S-PSS or S-SSS may repeat from (i) the configured / predefined symbols and (ii) the first symbol with the S-PSS or S-SSS until the last symbol containing the same number of symbols as in the repeating range in the second part, and further repeat in the frequency domain of the first part.

[0059] refer to Figure 6B The diagram shows a block diagram of the Sublink Synchronization Signal Block (S-SSB), whose repetition range contains interleaved (e.g., the synchronization signals on all symbols within the repetition range are different) multiple types of synchronization signals and PSBCH occupying different frequency range segments. Now refer to... Figure 6C The diagram illustrates a block diagram of a secondary link synchronization signal block (S-SSB) whose repeating range includes non-interleaved (e.g., the synchronization signal is the same on all symbols within the repeating range) single-type synchronization signals and PSBCH occupying different frequency range segments. As shown in these examples, a set of predefined symbols configured in the second part (e.g., symbols containing only S-PSS or symbols containing only S-SSS) can be repeated onto the predefined symbols configured in the first part.

[0060] Now for reference Figure 6D The diagram illustrates a block diagram of a secondary link synchronization signal block (S-SSB) whose repetition range includes interleaved (e.g., synchronization signals on all symbols within the repetition range are different) multiple types of synchronization signals occupying the entire frequency range. As shown in the example, in the second part, configured or predefined S-PSS, S-SSS, or PSBCH can be mapped to configured or predefined frequency ranges, such as the number of interleavings and the number of resource blocks (RBd).

[0061] Now for reference Figure 7A The diagram shows a block diagram of the secondary link synchronization signal block (S-SSB), where the first part repeats the single type of synchronization signal from the second part, occupying the entire frequency band. See also... Figure 7BThe diagram illustrates a block diagram of a Sublink Synchronization Signal Block (S-SSB), where the first part repeats the single-type synchronization signal of the second part, occupying the entire frequency band. In some embodiments, an S-PSS or S-SSS of length 127 can occupy no more than 11 RBs (132 REs), where REs {0, 1, 129, 130, 131} are set to 0. As shown, the symbol containing the S-PSS or S-SSS can be wrapped by the PSBCH. The PSBCH cannot be mapped to REs set to 0, and should not be mapped to intra-cell guard bands between RB sets. Reference Figure 7C The diagram illustrates a block diagram of a secondary link synchronization signal block (S-SSB), where the first part repeats the single type of synchronization signal and PSBCH from the second part, occupying the entire frequency band. All symbols within the repetition range should be repeated from symbols in the second part that have either S-PSS or S-SSS. This structure may have the advantage of distinguishing between the first part's mode and the second part's mode.

[0062] Predefined symbols (e.g., symbols containing only S-PSS or only S-SSS) can be repeated from the second part to the predefined symbols configured in the first part. Symbols for both the first and second parts can be generated, for example, by repeating the symbols from the second part to the symbol positions in the first part and mapping them to a time slot structure. Symbols from the second part can be mapped to positions within a time slot and then repeated to the configured or predefined symbols in the first part to generate a time slot structure.

[0063] A set of candidate start points can be set for the UE to perform channel access. If the Listen-Before-Speak (LBT) operation at a given start point is unsuccessful, the next start point will be used for the LBT operation. The UE can perform LBT at a candidate start point (e.g., the first symbol or before the first symbol).

[0064] If the LBT operation is successful, the S-SSB can be transmitted, and the mapped signal or channel between the initial candidate start point and the candidate start point where the LBT operation succeeded can be discarded. Only the mapped signal or channel after the candidate start point where the LBT operation succeeded can be transmitted. Otherwise, the LBT can be performed at another candidate start point, which can be 9 μs, 16 μs, or a symbol after the previous start point. The above procedure applies to S-SSBs that do not belong to a resource pool, such as S-SSBs whose time slots are not mapped by the resource pool association bitmap. For S-SSBs whose time slots are not mapped by the resource pool association bitmap, the start symbol index can take a value within the range {0, 1, 2, 3, 4, 5, 6, 7}.

[0065] The number of predefined or configured S-SSBs that do not belong to a resource pool and the number of S-SSBs that belong to a resource pool (e.g., S-SSBs whose time slots are mapped by a graph associated with the resource pool) can be configured within a specified frequency range (e.g., RB set, bandwidth portion (BWP), or carrier). These numbers can be the same or different. For S-SSBs whose time slots are mapped by a bitmap associated with the resource pool, the starting symbol index can be 0.

[0066] The configuration or predefined configuration of candidate start points that can identify at least one start point may include the number of candidate start points, the location of the start point, the index of the associated S-SSB in the resource pool (e.g., the S-SSB whose time slot is mapped by a bitmap associated with the resource pool), the priority level, or the LBT failure operation of the S-SSB that belongs to or does not belong to the resource pool (e.g., the number), etc.

[0067] B. When the Listen-Before-Speak (LBT) operation succeeds at the initial symbol, the transmission of the Sublink Synchronization Signal Block (S-SSB) begins. lose

[0068] like Figure 7A As shown in 7B, the number of PSBCH symbols can be mapped to a configured or predefined frequency resource, where the symbol index follows symbol 0, by using the number of interleaving symbols (e.g., 2, 3, 4, or 5), the number of RBs (e.g., 20, 30, 40, 50), or the number of symbols used for PSBCH mapping starting from a configured or predefined symbol index. The repetition range can be configured or predefined as the range of symbols between symbol 0 and the last symbol preceding the PSBCH start symbol. Now refer to... Figure 8 The diagram illustrates a block diagram of a secondary link synchronization signal block (S-SSB), where symbols with symbol indices are repeated in the first part, and symbols in the second part are repeated. The repeated S-PSS or S-SSS in the original symbols 1–2 and 3–4 can be mapped to symbols 0–1 and 2–3 respectively, based on the index in the second part; or the repeated S-PSS or S-SSS in symbols 5–6 and 7–8 can be mapped to symbols 0–1 and 2–3 respectively, based on the index of the entire time slot. In this case, the time slot structure can be transmitted when the LBT operation succeeds at symbol 0 and idleness is detected for a specified duration prior to symbol 0.

[0069] C. When the Listen-Before-Speak (LBT) operation fails at the initial symbol and succeeds at the next symbol, the secondary link... Transmission of step signal block (S-SSB)

[0070] The number of PSBCHs can be mapped to a configured or predefined frequency resource, where the symbol index follows symbol 0, using the number of interleavings (e.g., 2, 3, 4, or 5), the number of RBs, or the number of symbols used for PSBCH mapping starting from a configured or predefined symbol index. The repetition range can be configured or predefined as the range of symbols between symbol 0 and the last symbol before the PSBCH start symbol. Based on the index within the second part, the S-PSS or S-SSS repeating in the original symbols 1-2 and 3-4 can be mapped to symbols 0-1 and 2-3 respectively, or the S-PSS or S-SSS repeating in symbols 5-6 and 7-8 can be mapped to symbols 0-1 and 2-3 respectively, based on the index of the entire time slot. In this case, when the LBT operation fails at symbol 0 and idle is sensed for a specified duration before symbol 1, the time slot structure can be transmitted. The symbol S-PSS mapped to symbol 0 can be discarded, and the S-PSS, PSBCH, or S-SSS mapped from symbol 1 to the end of the time slot can be transmitted.

[0071] These are reflected in the examples depicted. (Reference) Figure 9A This depicts a block diagram of the Sublink Synchronization Signal Block (S-SSB), which discards the first symbol of the first part and has a second part containing various types of synchronization signals occupying different frequency bands and symbols, as well as the Physical Sublink Broadcast Channel (PSBCH). (See reference...) Figure 9B This depicts a block diagram of the Sublink Synchronization Signal Block (S-SSB), which discards the first symbol of the first part and has a second part consisting of a single type of synchronization signal occupying the entire frequency band. (Reference) Figure 9C This depicts a block diagram of the Sublink Synchronization Signal Block (S-SSB), which discards the first symbol of the first part and has a second part containing multiple types of synchronization signals occupying the entire frequency band.

[0072] D. Repetition range of the secondary link synchronization signal block (S-SSB) section

[0073] The number of repetition ranges can be predefined or configured within {1,2,3,4,5,6,7} symbols, and this number may vary depending on the configuration or predefined subcarrier spacing and interleaving number used for PSBCH mapping. For example, configuring 2 symbols as the number of symbols in the repetition range could mean setting the interleaving number for carrying the PSBCH to 3 at a 30kHz subcarrier spacing. In this case, the PSBCH could be at a rate matching floor(11 / 15*9) = 7 Orthogonal Frequency Division Multiplexing (OFDM) symbols, omitting 2 symbols as the repetition range. In another example, configuring 4 symbols as the number of symbols in the repetition range could mean setting the interleaving number for carrying the PSBCH to 2 at a 15kHz subcarrier spacing. In this case, the PSBCH could be at a rate matching floor(11 / 20*9) = 5 OFDM symbols, omitting 4 symbols as the repetition range.

[0074] Some other settings and PSBCH rate matching methods may result in additional repetition ranges, such as {1, 3, 5, 6, 7} symbols. The number of OFDM symbols can be derived from the association rules between the number of interleavings or RBs configured / defined for mapping the PSBCH and the subcarrier spacing of the S-SSB. One or more symbols of the S-PSS, S-SSS, or PSBCH can be mapped to symbols within the repetition range.

[0075] E. Symbol mapping relative to resource pool in secondary link synchronization block (S-SSB)

[0076] The number of S-SSBs configured or predefined as not belonging to a resource pool can be greater than the number of S-SSBs configured or predefined as belonging to a resource pool. A mapping ratio greater than 1 can be used to map the number of S-SSBs configured or predefined as not belonging to a resource pool to the number of S-SSBs configured or predefined as belonging to a resource pool, and the number of S-SSBs configured or predefined as not belonging to a resource pool can reside in different RB sets or BWPs. The above time slot structure can be applied to one or more S-SSBs configured or predefined as not belonging to a resource pool.

[0077] F. Configuration of candidate starting points for the Listen-The-After-Speak (LBT) operation

[0078] Candidate start points for LBT operations can be configured or predefined using different start points. These candidate start points are used for multiple S-SSBs configured within a frequency range (e.g., in different RB sets or BWPs). The number of candidate start points for LBT operations in one RB set may be less than the number of candidate start points for LBT operations in another RB set.

[0079] The position of a candidate start point for an LBT operation in one RB set can be earlier than the position of a candidate start point for an LBT operation in another RB set. The earlier the position of a candidate start point for an S-SSB in an RB set, or the fewer the number of candidate start points for LBT operations, the higher the priority of S-SSBs that do not belong to the resource pool or those associated with the resource pool. The earlier the position of a candidate start point for an S-SSB in an RB set, or the fewer the number of candidate start points for LBT operations, the more LBT failures occur for S-SSBs that do not belong to the resource pool or those associated with the resource pool. The position of a candidate start point for an S-SSB can be determined based on the number of candidate start points, the priority of S-SSBs that do not belong to the resource pool or those associated with the resource pool, and the number of LBT failures for S-SSBs that do not belong to the resource pool or those associated with the resource pool.

[0080] G. Procedure for performing Listen-Before-Speak (LBT) operation in secondary link communication

[0081] Now for reference Figure 10 A flowchart of a method 1000 for performing a Listen-Before-Speak (LBT) operation in secondary link communication is shown. Method 1000 can be implemented or performed using any of the components described above, such as BS 102 or 202 or UE 104 or 204, etc. In a brief overview, the wireless communication device can configure a secondary link synchronization signal block (S-SSB) (1005). The wireless communication device can perform an LBT operation with respect to the S-SSB (1010). The wireless communication device can detect that the LBT operation failed at a first point (“point A”) (1015). The wireless communication device can determine whether the LBT operation was successful at a second point (“point B”) after the first point (1020). If the LBT operation was successful at the second point, the wireless communication device can transmit a portion of the S-SSB starting from the second point (1025). The wireless communication device can also discard another portion of the S-SSB between the first and second points (1030). On the other hand, if the LBT operation fails at the second point, the wireless communication device can continue to perform the LBT operation at the third point (referred to as the second point again when determining the transmission) (1035).

[0082] More specifically, a wireless communication device (e.g., UE 104 or 204) may define or configure a Link Synchronization Signal Block (S-SSB) (1005). An S-SSB may include a set of resource elements or symbols defined across frequency and time for performing Listen-Before-Speak (LBT) operation. An S-SSB may identify or include a first portion and a second portion, etc. Each of the first and second portions may include a corresponding subset of resource elements or symbols for secondary link synchronization. The first portion may, depending on the configuration of the second portion, copy, repeat, or duplicate one or more symbols of the second portion. In some embodiments, the first portion may, depending on the configuration of the first portion, repeat one or more symbols of the second portion.

[0083] The first part can correspond to the repeating range portion of S-SSB (e.g., such as...). Figures 6A-6C (as shown), and may include a subset of symbols in the second part. In some embodiments, the first part of the S-SSB may repeat one or more symbols of one type, which is one of several types used for secondary link synchronization. Symbols may correspond to resource blocks or resource elements defined across frequency and time. The several types may identify or include one or more of the following: Secondary Link Primary Synchronization Signal (S-PSS) or Secondary Link Secondary Synchronization Signal (S-SSS), etc. One or more repeating symbols may begin before the initial symbol of the second part of the S-SSB, which is the initial symbol of the Physical Secondary Link Broadcast Channel (PSBCH) symbol.

[0084] In some embodiments, the first portion of the S-SSB may repeat a repetition range corresponding to one or more symbols in the second portion. The repetition range may be based on one or more of the number of symbols used for mapping, subcarrier spacing, number of redundancies (RBs), or number of interleavings. Mapping may be a mapping between one or more symbols in the first portion of the S-SSB and one or more symbols in the second portion of the S-SSB. The number of symbols may correspond to the number of symbols in the S-PSS, S-SSS, or PSBCH, etc. The subcarrier spacing (SCS) may correspond to the reciprocal of the symbol time in the specified channel. The number of interleavings may correspond to the number of times the specified set of symbols (e.g., S-PSS and S-SSS) repeats within the repetition range of the S-SSB.

[0085] The S-SSB configured for LBT operation by the wireless communication device may be located outside the resource pool, with at least one other S-SSB belonging to the resource pool. In some embodiments, a first number of S-SSBs not belonging to the resource pool and a second number of S-SSBs belonging to the resource pool can be configured or predefined separately. In some embodiments, the mapping ratio between the first number of S-SSBs not belonging to the resource pool and the second number of S-SSBs belonging to the resource pool is predefined. In some embodiments, the first number defined within a resource block (RB) set or bandwidth portion (BWP) may be different from or the same as the second number of symbols.

[0086] The wireless communication device can perform, execute, or implement LBT operations regarding the S-SSB (1010). The wireless communication device can perform LBT operations in unlicensed spectrum to enable S-SSB transmission in a secondary link operation. While performing this operation, the wireless communication device can monitor or sense other communications (e.g., signals or channels) within the unlicensed spectrum. Through sensing, the wireless communication device can determine whether other communications exist on the same resources as the S-SSB (e.g., resources defined in time and frequency) in the unlicensed spectrum.

[0087] The wireless communication device can determine, identify, or detect an LBT operation failure at a first point (“Point A”) (1015). During LBT operation, if other communication exists on the same resource as the S-SSB in the monitored spectrum, the wireless communication device can detect the failure. By detecting the failure, the wireless communication device can measure, determine, or identify the first point in time of the failure. The wireless communication device can identify the first point from a set of candidate starting points for LBT operation and can define the first point within a set of resource blocks (RBs) or bandwidth portions (BWPs). The wireless communication device can then continue performing LBT operation with the first point as a reference.

[0088] The wireless communication device can identify or determine whether the LBT operation was successful at a second point (“Point B”) following the first point (1020). When performing the LBT operation, if there is no other communication on the same resource as the S-SSB after the first point, the wireless communication device can determine that the LBT operation was successful. If success is determined, the wireless communication device can measure, determine, or identify the second point at the time the success was detected. The wireless communication device can identify the second point from a set of candidate start points for the LBT operation (e.g., the same set as the first point) and can define the second point within a set of resource blocks (RBs) or bandwidth portions (BWPs). In some embodiments, between the first and second points, the first portion of the S-SSB can repeat one or more symbols of the second portion starting from the initial symbol index. Furthermore, the first portion can end the repetition at a terminating symbol index preceding the initial symbol of the Physical Sublink Broadcast Channel (PSBCH).

[0089] Alternatively, when other communications exist on the same resource as the S-SSB, the wireless communication device can determine that the LBT operation after the first point has failed. In the case of failure, the wireless communication device can promptly measure, determine, or identify the second point (also referred to herein as the third point) until success is detected. During the execution of the LBT operation at the third point, the identification of the second point for successful LBT operation should continue; the third point is 9 μs, 16 μs, or a symbol following the previous second point. The third point can be identified by the wireless communication device from a set of candidate starting points for LBT operation (e.g., the same set as the first point), and the second point can be defined within a set of resource blocks (RBs) or bandwidth portions (BWPs).

[0090] The wireless communication device can identify a first point, a second point, and a third point from a set of candidate start points for LBT operation. In some embodiments, the first number of candidate start points for LBT operation in the first RB set is less than the second number of candidate start points for LBT operation in the second RB set. In some embodiments, the first position of at least one first candidate start point for LBT operation in the first RB set may be earlier than the second position of at least one second candidate start point for LBT operation in the second RB set.

[0091] If the LBT operation is successful at the second point, the wireless communication device can send, provide, or transmit a portion of the S-SSB starting from the second point (1025). This portion of the SSB can be mapped from the second point to one or more time-domain resources (e.g., symbols or intervals between symbols). In some embodiments, upon success at the second point corresponding to the initial symbol index, the wireless communication device can transmit the entire S-SSB mapped to one or more time-domain resources.

[0092] Regarding resource pools, the portion of the S-SSB to be transmitted may be unrelated to the resource pool of another S-SSB set. In some embodiments, the transmission of S-SSBs may be limited to only the second S-SSB set. The second S-SSB set may be located on a time slot not mapped by a resource pool association bitmap. In some embodiments, the entire first S-SSB set may be transmitted when the second point corresponds to the initial symbol index. The first S-SSB set may be located on a time slot mapped by a resource pool association bitmap.

[0093] The wireless communication device may also release or discard another portion (1030) of the S-SSB between the first and second points during transmission. In some embodiments, the wireless communication device may discard at least one symbol corresponding to the initial symbol index during transmission. The discarding of a symbol may be in response to: (i) a failure at the first point corresponding to the initial symbol index; and (ii) a success at a second point corresponding to at least one index after the initial symbol index.

[0094] On the other hand, if the LBT operation fails at the second point, the wireless communication device can continue to perform the LBT operation at the third point (1035). The third point can be, for example, 9 μs, 16 μs, or a symbol after the second point. If the LBT operation succeeds, the third point can replace the second point, and transmission can begin from the second point, discarding the S-SSB symbols between the first and second points. Alternatively, the LBT operation can continue at points after the third point until the LBT operation succeeds at the designated point that replaces the second point. In some embodiments, the wireless communication device can determine that the LBT operation succeeds at the third point for an S-SSB after the first point. When the LBT operation succeeds at the third point, the wireless communication device can begin transmitting a second portion of the S-SSB, the second portion having one or more resources (e.g., time-domain resources) or symbols starting from the third point.

[0095] While various embodiments of this solution have been described above, it should be understood that they are presented by way of example only and not by way of limitation. Similarly, various diagrams may depict example architectures or configurations, and these diagrams are provided to enable those skilled in the art to understand the exemplary features and functionality of this solution. However, those skilled in the art will understand that the solution is not limited to the example architectures or configurations shown, but can be implemented using various alternative architectures and configurations. Furthermore, as those skilled in the art will understand, one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of this disclosure should not be limited to any of the illustrative embodiments described above.

[0096] It should also be understood that any reference to elements in this document using names such as "first," "second," etc., generally does not restrict the number or order of these elements. Rather, these names serve as a convenient means of distinguishing two or more elements or instances of elements. Therefore, references to the first and second elements do not imply that only two elements can be used, or that the first element must somehow precede the second element.

[0097] Furthermore, those skilled in the art will understand that information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, and symbols that may be referenced in the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0098] Those skilled in the art will also understand that any of the various illustrative logic blocks, modules, processors, devices, circuits, methods, and functions related to the aspects disclosed herein can be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of both), firmware, various forms of programs, or design code containing instructions (which may be referred to herein as "software" or "software module" for convenience) or any combination of these technologies. To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been described above in general terms of functionality. Whether these functions are implemented as hardware, firmware, or software, or as a combination of these technologies, depends on the specific application and the design constraints imposed on the system as a whole. Those skilled in the art can implement the described functions in various ways for each specific application, but such implementation decisions will not deviate from the scope of this disclosure.

[0099] Furthermore, those skilled in the art will understand that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented within or executed by an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, or any combination thereof. Logic blocks, modules, and circuits may also include antennas and / or transceivers for communication with various components within a network or device. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other suitable configuration to perform the functions described herein.

[0100] If implemented in software, the functionality can be stored as one or more instructions or code on a computer-readable medium. Therefore, the steps of the methods or algorithms disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media include computer storage media and communication media, including any medium capable of transferring computer programs or code from one place to another. Storage media can be any available medium accessible to a computer. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to store the desired program code in the form of instructions or data structures and is accessible to a computer.

[0101] In this document, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements used to perform the relevant functions described herein. Furthermore, for ease of discussion, various modules are described as discrete modules; however, as will be apparent to those skilled in the art, two or more modules can be combined to form a single module that performs the relevant functions according to embodiments of this solution.

[0102] Furthermore, in embodiments of this solution, memory or other storage and communication components may be employed. It should be understood that, for clarity, embodiments of this solution have been described above with reference to different functional units and processors. However, it is apparent that any suitable functional distribution among different functional units, processing logic elements, or domains can be used without departing from this solution. For example, functions illustrated as being performed by a separate processing logic element or controller may be performed by the same processing logic element or controller. Therefore, references to specific functional units are merely references to suitable means for providing said functions and do not indicate a strict logical or physical structure or organization.

[0103] Those skilled in the art will readily recognize that various modifications to the embodiments described in this disclosure, as well as the general principles defined herein, can be applied to other embodiments without departing from the scope of this disclosure. Therefore, this disclosure is not intended to limit itself to the embodiments shown herein, but should be accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the appended claims.

Claims

1. A method of performing a listen-before-talk, LBT, operation in sidelink communications, comprising: performing, by a wireless communication device, an LBT operation with respect to a synchronization signal block, S-SSB, within an interior of the S-SSB, the S-SSB having a first portion and a second portion, wherein the first portion repeats one or more symbols of the second portion according to a configuration of the second portion; determining, by the wireless communication device, a failure of the LBT operation at a first point of the S-SSB; determining, by the wireless communication device, a success of the LBT operation at a second point of the S-SSB, the second point being after the first point; and transmitting, by the wireless communication device, at least a portion of the S-SSB in response to the success, the at least a portion mapping to one or more time domain resources starting from the second point.

2. The method of claim 1, further comprising: determining, by the wireless communication device, a second failure of the LBT operation at a third point of the S-SSB, the third point being after the first point; and transmitting, by the wireless communication device, a second portion of the S-SSB in response to the success at the second point, the second portion having one or more second time domain resources starting from the second point.

3. The method of claim 1, further comprising: determining, by the wireless communication device, a success of the LBT operation at a third point of the S-SSB, the third point being after the first point; and transmitting, by the wireless communication device, a second portion of the S-SSB in response to the success at the third point, the second portion having one or more second time domain resources starting from the third point. discarding, by the wireless communication device, a second portion of the S-SSB in the transmission between the first point and the second point in response to the success. the first portion of the S-SSB repeats one or more symbols of a type, the type being one of a plurality of types for sidelink synchronization, the plurality of types including at least one of a sidelink primary synchronization signal, S-PSS, or a sidelink secondary synchronization signal, S-SSS.

4. The method of claim 1, further comprising: the first portion repeats one or more symbols of the second portion according to a configuration of the first portion of the S-SSB.

5. The method of claim 1, wherein, the first portion of the S-SSB repeats one or more symbols of the second portion starting at an initial symbol index and ending at a terminal symbol index, the terminal symbol index being before an initial symbol of a physical sidelink broadcast channel, PSBCH.

6. The method of claim 1, wherein, the transmission of the S-SSB applies to a second set of S-SSBs only.

7. The method of claim 1, wherein, the second set of S-SSBs is on a time slot not mapped by a resource pool association bitmap.

8. The method of claim 1, wherein, the entire first set of S-SSBs is transmitted in a case where the second point corresponds to the initial symbol index.

9. The method of claim 8, wherein, the first set of S-SSBs is on a time slot mapped by a resource pool association bitmap.

10. The method of claim 1, wherein, ​ 11. The method of claim 10, wherein, ​ 12. The method of claim 7, wherein, The transmission further comprises transmitting an entire S-SSB in response to success at a second point corresponding to the initial symbol index, the entire S-SSB being mapped to the one or more time domain resources.

13. The method of claim 7, further comprising: In response to (i) failure at a first point corresponding to the initial symbol index and (ii) success at a second point corresponding to at least one index after the initial symbol index, dropping, by the wireless communication device, at least one initial symbol corresponding to the initial symbol index in a transmission. (i) failure at a first point corresponding to the initial symbol index; and (ii) success at a second point corresponding to at least one index after the initial symbol index. The first portion of the S-SSB repeats a repetition range corresponding to one or more symbols of the second portion based on at least one of a number of symbols for mapping, a subcarrier spacing, a number of resource blocks, RBs, or a number of interlaces.

14. The method of claim 1, wherein, A first number of S-SSBs not belonging to a resource pool and a second number of S-SSBs belonging to the resource pool are configured separately or predefined separately.

15. The method of claim 1 or 7, wherein, A mapping ratio between the first number of S-SSBs not belonging to the resource pool and the second number of S-SSBs belonging to the resource pool is predefined.

16. The method of claim 1 or 7, wherein, The first number and the second number of symbols are the same or different within a set of resource blocks, RBs, or a bandwidth part, BWP.

17. The method of claim 15, wherein, The first point and the second point are identified from a plurality of candidate starting points for an LBT operation, each candidate starting point being defined within at least one of a set of resource blocks, RBs, or a bandwidth part, BWP.

18. The method of claim 1, wherein, A first number of candidate starting points for the LBT operation in a first set of RBs is less than a second number of candidate starting points for the LBT operation in a second set of RBs.

19. The method of claim 15, wherein, A first location of at least one first candidate starting point for the LBT operation in the first set of RBs is earlier than a second location of at least one second candidate starting point for the LBT operation in the second set of RBs.

20. The method of claim 15, wherein, The processor is configured to read code from the memory and perform the method according to any one of claims 1 to 20.

21. A wireless communication device comprising a processor and a memory, wherein, 22. A computer program product comprising a computer readable program medium code stored thereon, which when executed by a processor, causes the processor to perform the method according to any one of claims 1 to 20. ​

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