Methods, devices, and computer-readable media for sidelink transmissions

Abstract

Embodiments of the present disclosure relate to methods, devices, apparatuses, and computer readable media for sidelink transmission. According to embodiments of the present disclosure, a first device determines a target transmission starting position from a group of candidate transmission starting positions in a sidelink slot based on an access category of a sidelink transmission to be performed. The first device performs a listen before talk (LBT) before the target transmission starting position. If the LBT is successful, the first device performs the sidelink transmission from the target transmission starting position. In this way, the use of mode 2 over shared / unlicensed spectrum is enabled while addressing the issue of unsensed (undetected) SPS transmission due to LBT failure and making mode 2 more robust system for LBT failure due to other coexistence.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to communication technologies, and more specifically to methods, apparatus, and computer-readable media for sidelink transmission. Background Technology

[0002] With the development of communication systems, new technologies have been proposed. Terminal devices can establish sidelinks with each other to allow directional communication between them. For a group of terminal devices, sidelink communication can include unicast, multicast, and broadcast communication. Terminal devices can utilize unlicensed spectrum to perform sidelink (SL) communication. Summary of the Invention

[0003] Typically, embodiments of this disclosure relate to a technical solution for sidelink transmission.

[0004] In a first aspect, embodiments of this disclosure provide a first device. The first device includes: at least one processor; and at least one memory, including computer program code; the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to: determine a target transmission start position from a set of candidate transmission start positions in a sidelink time slot based on the access level of the sidelink transmission to be performed; perform a listen-before-speak operation on a sidelink channel prior to the target transmission start position; and, if the listen-before-speak operation is determined to be successful, perform the sidelink transmission from the target transmission start position.

[0005] In a second aspect, embodiments of this disclosure provide a method. The method includes: determining a target transmission start position from a set of candidate transmission start positions in a sidelink time slot based on the access level of the sidelink transmission to be performed; performing a listen-before-speak operation on a sidelink channel prior to the target transmission start position; and, if the listen-before-speak operation is determined to be successful, performing the sidelink transmission from the target transmission start position.

[0006] In a third aspect, embodiments of this disclosure provide an apparatus for communication. The apparatus includes components for determining a target transmission start position from a set of candidate transmission start positions in a sidelink time slot based on the access level of the sidelink transmission to be performed; components for performing a listen-before-speak operation on the sidelink channel prior to the target transmission start position; and components for performing the sidelink transmission from the target transmission start position if the listen-before-speak operation is determined to be successful.

[0007] In a fourth aspect, embodiments of this disclosure provide a computer-readable medium. The computer-readable medium stores instructions that, when executed by at least one processing unit of a machine, cause the machine to implement the method according to the second aspect.

[0008] It should be understood that the summary section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0009] Some exemplary embodiments will now be described with reference to the accompanying drawings, in which:

[0010] Figure 1 A schematic diagram illustrating uplink operation in unlicensed spectrum according to conventional techniques is shown.

[0011] Figure 2 A schematic diagram of a communication environment in which embodiments of the present disclosure may be implemented is shown;

[0012] Figure 3 Signaling diagrams of side-link transmissions in an unlicensed carrier according to certain example embodiments of the present disclosure are shown;

[0013] Figure 4 A schematic diagram of side link time slots according to certain example embodiments of the present disclosure is shown;

[0014] Figure 5 A schematic diagram of side link time slots according to certain example embodiments of the present disclosure is shown;

[0015] Figure 6 A schematic diagram illustrating the selection of transmission according to certain exemplary embodiments of this disclosure is shown;

[0016] Figures 7A-7C A schematic diagram showing several starting positions according to certain example embodiments of the present disclosure is provided;

[0017] Figures 8A-8C A schematic diagram showing several starting positions according to certain example embodiments of the present disclosure is provided;

[0018] Figures 9A-9C A schematic diagram showing several starting positions according to certain example embodiments of the present disclosure is provided;

[0019] Figures 10A-10C A schematic diagram showing several starting positions according to certain example embodiments of the present disclosure is provided;

[0020] Figures 11A-11C A schematic diagram showing several starting positions according to certain example embodiments of the present disclosure is provided;

[0021] Figures 12A-12C A schematic diagram showing several starting positions according to certain example embodiments of the present disclosure is provided;

[0022] Figure 13A flowchart is shown illustrating a method implemented at a first device according to certain example embodiments of the present disclosure;

[0023] Figure 14 A simplified block diagram of an apparatus suitable for implementing exemplary embodiments of the present disclosure is shown; and

[0024] Figure 15 A block diagram of an example computer-readable medium according to some example embodiments of the present disclosure is shown.

[0025] In all the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0026] The principles of this disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and implementing this disclosure, and do not impose any limitation on the scope of this disclosure. In addition to those described below, the embodiments described herein can be implemented in various other ways.

[0027] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0028] References to "an embodiment," "embodiment," "example embodiment," etc., in this disclosure indicate that the described embodiment may include specific features, structures, or characteristics, but it is not necessary for every embodiment to include specific features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in connection with an embodiment, it can be assumed that in conjunction with other embodiments (whether explicitly described or not) affecting such a feature, structure, or characteristic is within the knowledge of those skilled in the art.

[0029] It should be understood that although the terms “first” and “second” may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0030] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that, when used herein, the terms “comprising,” “including,” “having,” “having,” “containing,” and / or “comprising” specify the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0031] As used in this application, the term "circuit system" may refer to one or more of the following:

[0032] (a) Pure hardware circuit implementation (such as implementations only in analog and / or digital circuit systems); and

[0033] (b) A combination of hardware circuitry and software, such as (if applicable):

[0034] (i) A combination of analog and / or digital hardware circuitry with software / firmware, and

[0035] (ii) Any part of a hardware processor (including (multiple) digital signal processors), software, and (multiple) memories, which work together to cause a device such as a mobile phone or server to perform various functions; and

[0036] (c) Multiple hardware circuits and / or multiple processors, such as microprocessors or parts thereof, that require software (e.g., firmware) to function but may not exist when not in use.

[0037] This definition of "circuit system" applies to all uses of the term in this application, including in any claim. As another example, as used in this application, the term "circuit system" also covers implementations of pure hardware circuitry or processors (or processors in general) or hardware circuitry or processors and their accompanying software and / or firmware. The term "circuit system" also covers (e.g., and if applicable to a particular claim element) baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or networking devices.

[0038] As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-A Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. Furthermore, communication between terminal devices and network devices in the communication network can be performed according to any suitable generation of communication protocol, including but not limited to first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, future fifth-generation (5G) communication protocols, and / or any other currently known or to be developed in the future. Embodiments of this disclosure can be applied to a variety of communication systems. Given the rapid development of communications, there will naturally be future types of communication technologies and systems that embody the future types of this disclosure. The scope of this disclosure should not be limited to the systems described above only.

[0039] As used herein, the term "network device" refers to a node in a communication network through which terminal devices access the network and receive services. Network devices can refer to base stations (BS) or access points (APs), such as Node B (NodeB or NB), evolved Node B (eNodeB or eNB), NR NB (also known as gNB), Remote Radio Unit (RRU), Radio Header (RH), Remote Radio Header (RRH), relay, integration and access backhaul (IAB) nodes, low-power nodes (such as femtons, picons), non-terrestrial network (NTN) or non-terrestrial network equipment (such as satellite network equipment, low Earth orbit (LEO) satellites and geostationary Earth orbit (GEO) satellites), aircraft network equipment, etc., depending on the terminology and technology relevant to the application. The term "terminal device" refers to any terminal device capable of wireless communication. In the following description, the terms "terminal device," "terminal," "user equipment," and "UE" are used interchangeably.

[0040] In unlicensed frequency bands below 7 GHz, NR coexistence with other systems is ensured via a Listen-Before-Speak (LBT) channel access mechanism. Here, a UE intending to perform a sidelink transmission must successfully complete an LBT check before it can initiate a transmission. The term "Listen-Before-Speak (LBT)" as used herein refers to a technique used in communications where a device senses its radio environment before initiating its transmission. For a UE to pass the LBT check, it must observe that the channel is available for multiple consecutive Free Channel Assessment (CCA) slots. Below 7 GHz, these slots last for 9 μs. If the measured power (i.e., the energy collected during the CCA slots) is below a rule-defined threshold (which can vary depending on the operating band and geographic region), the UE considers the channel available in the CCA slots.

[0041] When a UE initiates communication (i.e., the UE acts as the initiating device), the UE must obtain the "right" to access the channel for a certain period of time, which is called the Channel Occupancy Time (COT) in the rules (e.g., Figure 1 The duration shown is 120 – achieved by applying the “extended” LBT procedure, where the channel must be treated as idle for the entire duration of the contention window (CW) (shown as...). Figure 1 The duration of LBT is 110. This "extended" LBT process is often referred to as LBT Category 4 (LBT Cat. 4).

[0042] Resources for sidelink communication can be scheduled by network devices, which is referred to as Mode 1. Alternatively, resources for sidelink communication can be determined by the UE itself, which is referred to as Mode 2. In Mode 2, the SL UE autonomously performs resource selection through a sensing process. More specifically, the SL transmitting (TX) UE in NR SL Mode 2 first performs a sensing process on the configured SL transmission resource pool(s) to obtain information about reserved resources from nearby SL TX UE(s). Based on the knowledge obtained from sensing, the SL TX UE can select (multiple) resources from the available SL resources accordingly. For the SL UE to perform sensing and obtain the necessary information to receive SL transmissions, it needs to decode the Sidelink Control Information (SCI). The term "sidelink" refers to a link between two terminal devices that enables device-to-device communication. The term "TX UE" as used herein can refer to a UE that can send data to another UE when performing sidelink communication with that UE. The term "receiving (RX) UE" as used herein can refer to a UE that can receive data from another UE when performing sidelink communication with that UE.

[0043] As previously discussed, in New Radio (NR) SL resource allocation mode 2, the UE performs autonomous resource selection via a sense-based collision avoidance mechanism. This collision avoidance mechanism is based on the UE detecting and decoding sidelink channel information (SCI) transmitted by other devices during the sensing period. Based on these SCIs, the sensing UE can determine which future resources will be used for (i) transmissions within the same transport block (e.g., initial transmissions and retransmissions) and (ii) transmissions in different transport blocks (for semi-static / periodic services, referred to herein as SPS).

[0044] In case (i), the SL device can indicate up to two additional resources during transmission, in which it will perform the transmission (e.g., implement blind retransmission and its soft combination at the SL receiver), the only limitation being that these resources occur 31 times before the start of the original transmission. In case (ii), the indication of future resources follows the period indicated in the first-stage SCI. These two methods can, of course, be combined. Furthermore, aperiodic transmissions following the same structure as (i) are also possible, but the indicated resources for retransmissions of the original transport block (TB) are not necessarily different.

[0045] By decoding the SCIs of other UEs, the sensing UE knows the future reservations of other UEs and can avoid selecting resources that would conflict with them. The decision also takes into account the priority of the sensing UE's own transmissions and the transmissions of other UEs, as well as the corresponding Measurement Reference Signal Received Power (RSRP).

[0046] However, no sense-based conflict avoidance mechanism was designed when considering operations in shared / unlicensed spectrum and the requirement to perform LBT checks every time a UE needs to perform a transmission. Taking SL semi-static scheduling (SPS) as an example, if the NR SL must share spectrum with Wi-Fi, two problems arise: (1) the Wi-Fi node does not decode the SCI, and therefore does not avoid conflicts with reserved resources (as indicated by the SL device in its previous SPS transmission); (2) if the sidelink device must perform LBT before its SPS TX, it may have to skip its reserved resources and use unreserved resources instead, thus reducing the reservation value for conflict avoidance.

[0047] To at least partially address the aforementioned and other potential problems, a sidelink transmission scheme is proposed. According to embodiments of this disclosure, a first device determines a target transmission start position from a set of candidate transmission start positions in the sidelink time slot based on the access level of the sidelink transmission to be performed. The first device performs a Level-Based Transmission (LBT) before the target transmission start position. If the LBT is successful, the first device performs the sidelink transmission from the target transmission start position. In this way, the use of Mode 2 on shared / unlicensed spectrum is realized, while solving the problem of unsensitized (undetected) SPS transmission due to LBT failure, and making Mode 2 more robust to LBT failures due to other coexisting systems.

[0048] Figure 2A schematic diagram of a communication environment 200 in which embodiments of the present disclosure may be implemented is shown. The communication environment 200, as part of a communication network, includes devices 210-1, 210-2, ..., 210-N (collectively referred to as "device 210"). Device 210 may be a terminal device. Alternatively, device 210 may be a vehicle. The communication environment 200 may also include a network device 220.

[0049] Communication environment 200 may include any suitable number of devices. In communication environment 200, device 210 and network device 220 can transmit data and control information to each other. Device 110 can communicate with each other. The link from network device 220 to device 210 is called a downlink (DL), and the link from device 210 to network device 220 is called an uplink (UL). Links between devices 210 are called sidelinks (SL). Links between vehicles are called SL, and links between terminal devices and vehicles are also called SL.

[0050] It should be understood that Figure 2 The number of devices and cells shown and their connections are given for illustrative purposes and no limitations are imposed. The communication environment 200 may include any suitable number of devices and networks suitable for implementing embodiments of this disclosure.

[0051] Communication in communication environment 200 can be implemented according to any suitable communication protocol, including but not limited to cellular communication protocols such as first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G), wireless local area network communication protocols such as IEEE 802.11, and / or any other currently known or to be developed in the future. Furthermore, communication can utilize any suitable wireless communication technology, including but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), Discrete Fourier Transform Spread Spectrum OFDM (DFT-s-OFDM), and / or any other currently known or to be developed in the future.

[0052] Exemplary embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Figure 2 , Figure 2 A signaling stream 200 for sidelink transmission according to an example embodiment of this disclosure is shown. Reference will be made to this example for discussion purposes. Figure 2Describe signaling flow 200. Signaling flow 200 may include a first device and a set of second devices capable of communicating with the first device. The first device may be any device capable of sidelink communication. For example, the first device may be a terminal device or a vehicle. The second device may be any suitable device capable of communicating with the first device. For example, the second device may be a terminal device or a vehicle. For illustrative purposes only, device 210-1 is used as an example of a first device, and device 210-2 is used as an example of a second device. It should be noted that the second device may include any suitable device.

[0053] Device 210-1 (hereinafter referred to as "first device") can determine the 3055 access level based on its transmission type. Based on this access level, device 210-1 determines a 3010 target transmission start position from a set of candidate transmission start positions. In some embodiments, device 210-1 can determine the target transmission start position from multiple transmission start positions. The LBT start position can be selected by device 210-1 based on: the assigned transmission start position, the applied LBT type, and, in the case of LBT type 1 in the contention window associated with the channel access priority of the UE transmission. It should be understood that a set of transmission start positions can include any number of transmission start positions. Figure 4 As shown, the sidelink time slots include 14 symbols: symbols 410-1, 410-2, 410-3, 410-4, 410-5, 410-6, 410-7, 410-8, 410-9, 410-10, 410-11, 410-12, 410-13, and 420. Multiple transmission start positions can be configured in symbol 410-1. For example, the first transmission start position can be configured in duration 440-1, the second transmission start position can be configured in duration 440-2, and the third transmission start position can be configured in duration 440-3.

[0054] Table 1 shows an example of the mapping between access level and sidelink transport type. It should be understood that Table 1 is only an example and not a limitation.

[0055] Table 1

[0056]

[0057]

[0058] As an example only, if the type of sidelink transmission is an ongoing sidelink semi-static scheduling transmission and the access level of that sidelink transmission is Access Level 1, device 210-1 can select a first transmission start position from a set of transmission start positions. Similarly, if the type of sidelink transmission is a retransmission of a previous SL SPS transmission and the access level of that sidelink transmission is Access Level 1, a first transmission start position can be selected. In this case, as... Figure 4 As shown, device 210-1 can select the first transmission start position in duration 440-1.

[0059] In other embodiments, if the sidelink transmission type is SL SPS establishment (in other words, the first SL SPS transmission) and the access level of the sidelink transmission is Access Level 2, device 210-1 can select a second transmission start position from this group of transmission start positions. Similarly, if the sidelink transmission type is a one-time transmission with control signaling and the access level of the sidelink transmission is Access Level 2, a second transmission start position can be selected. Alternatively, if the sidelink transmission type is a one-time transmission of user plane services with high QoS requirements and the access level of the sidelink transmission is Access Level 2, device 210-1 can select a second transmission start position from this group of transmission start positions. In this case, as Figure 4 As shown, device 210-1 can select a second transmission start position within a duration of 440-2.

[0060] In another embodiment, if the sidelink transmission is a one-time transmission of a user plane service with more lenient QoS requirements, and the access level of the sidelink transmission is access level 3, then device 210-1 can select a third transmission start position from this group of transmission start positions. In this case, as... Figure 4 As shown, device 210-1 can select a third transmission start position within a duration of 440-3.

[0061] In some embodiments, a lower access level (e.g., access level 1) can be used for ongoing SL SPS, retransmissions of previous SL SPS transmissions, and retransmissions of aperiodic transmissions (within previously indicated resources). In other words, any transmission that at some point in the past indicated a resource to be used in the first-phase SCI. Alternatively, a higher access level (e.g., access level 2) can be used for transmissions in the first-phase SCI associated with a previous transmission that did not have a previously indicated resource.

[0062] In another embodiment, the priority field indicated in the SCI corresponds to the priority of the actual transmission provided by the higher layer. Table 2 below shows the mapping between access levels, the priority field indicated in the SCI, and sidelink transmission types. It should be noted that Table 2 is merely an example and not a limitation.

[0063] Table 2

[0064]

[0065]

[0066] Figure 5 A schematic diagram of sidelink time slots according to some example embodiments of the present disclosure is shown. For example... Figure 5 As shown, there are two transmission start positions, 530-1 and 530-2. Transmission start position 530-1 has a higher priority than transmission start position 530-2. At transmission start position 530-1, transmission failure may be caused by other systems (e.g., Wi-Fi). At transmission start position 530-2, transmission failure may be caused by the same system or another system.

[0067] As an example only, if the access level of the sidelink transmission 510 is Access Level 1, then device 210-1 can select a transmission start position 530-1 as the target transmission start position for the sidelink transmission 510. The LBT can be performed over a duration of 540. The end point of the LBT can coincide with the start position 530-1.

[0068] Additionally, if the access level of sidelink transmission 520 (e.g., access level 2) is greater than the access level of sidelink transmission 510, device 210-1 can select transmission start position 530-2 as the target transmission start position for sidelink transmission 510. LBT can be performed over a duration 560. The endpoint of LBT can coincide with transmission start position 530-2. In some embodiments, LBT can be completed at the target transmission start position. Alternatively, LBT can be completed before the target transmission start position. Figure 5 As shown, no transmission occurred in symbol 550.

[0069] Device 210-1 performs a 3015 LBT on the sidelink channel prior to the target transmission start position. The LBT may include any channel access operations related to the LBT. In some embodiments, device 210-1 may determine the target transmission start position from multiple transmission start positions based on the target transmission start position. For example, the LBT end position may coincide with the target transmission start position.

[0070] For device 210-1 to pass the LBT check, device 210-1 should observe that the channel is available for multiple consecutive Free Channel Assessment (CCA) slots. Below 7 GHz, the duration of these slots is 9 μs. If the measured power (i.e., the energy collected during the CCA slot) is below a specified threshold (which may depend on the operating frequency band and geographic area), device 210-1 considers the channel available in the CCA slot. As shown in Table 3, the durations of COT and CW depend on the Channel Access Priority (CAPC) associated with the UE service. Control plane services (e.g., PSCCH) are transmitted with p=1, while user plane services have p>1.

[0071] Table 3

[0072]

[0073] like Figure 6 As shown, device 210-1 can perform sensing to identify which resources are available for its periodic transmission during sensing period 6010. Device 210-1 can select which resources to use for transmitting future periodic transmissions of device 210-1 within period 6030. Device 210-1 can perform its first transmission within period 6030. For example, there is no transmission in symbol 610-1. Device 210-1 can perform LBT within symbol 610-2. Device 210-1 can perform automatic gain control (AGC) within symbol 610-3 and transmit data or control information within duration 610-4. There is also a guard symbol 610-5.

[0074] In addition, device 210-1 can perform its second transmission within time period 6040. Device 210-1 can perform LBT within symbol 620-1. Device 210-1 can perform automatic gain control (AGC) in symbols 620-2 and 620-3, and transmit data or control information within duration 620-4. There is also a protection symbol 610-5.

[0075] In addition, device 210-1 can perform its third transmission within time period 6040. Device 210-1 can perform LBT within symbol 630-1. Device 210-1 can perform automatic gain control (AGC) in symbols 630-2 and 630-3, and transmit data or control information within duration 630-4. There is also a protection symbol 630-5.

[0076] Return to reference Figure 3If LBT succeeds, device 210-1 performs a 3020 sidelink transmission. In some embodiments, device 210-1 may perform a sidelink transmission to a receiving device (e.g., device 210-2). Alternatively, device 210-1 may perform a sidelink transmission to a group of devices. For example, the sidelink transmission may be multicast. In other embodiments, device 210-1 may perform a sidelink transmission to all devices. For example, the sidelink transmission may be broadcast. For illustrative purposes only, the case of configuring two transmission start positions is described. Figure 7A-12C It should be noted that any suitable number of transmission start positions can be configured.

[0077] For example, such as Figures 7A-7C As shown, two transmission start positions can be configured within symbol 710-1. The first transmission start position in time can have a higher priority than the second transmission start position in time. In other words, the first transmission start position is earlier in time than the second transmission start position. Symbols 710-2, 710-3, 710-5, 710-6, 710-7, 710-8, 710-10, 710-11, 710-12, and 710-13 can be used for the Physical Side Link Shared Channel (PSSCH). Symbols 710-2 and 710-3 can also be used for the Physical Side Link Control Channel (PSDCH). Symbols 710-4 and 710-9 can be used to transmit the Demodulation Reference Signal (DMRS). Symbol 720 is a protection symbol.

[0078] like Figure 7B As shown, if device 210-1 selects the first of two transmission start positions, LBT can be completed at or before the first transmission start position. For example, LBT should be completed before symbol 710-1. If device 210-1 successfully performs LBT, it can transmit the AGC symbol in symbol 710-1. Device 210-1 can transmit at least one of data or control information from symbol 710-2.

[0079] like Figure 7C As shown, if device 210-1 selects the second transmission start position out of two transmission start positions, the LBT can be completed at or before the second transmission start position. For example, device 210-1 can perform the LBT during duration 710-1-1. If device 210-1 successfully performs the LBT, it can transmit the CP (connected to symbol 710-2) of the side link for the remaining time of duration 710-1-2 to fill the gap between the start position and the start symbol boundary of symbol 710-2.

[0080] As another embodiment, a first transmission start position (high priority start position) can be configured within the protection symbol of a previous sidelink time slot, and a second transmission start position (low priority start position) can be configured within the first symbol of the current sidelink time slot. For example, such as Figures 8A-8C As shown, the first transmission start position can be configured in symbol 830 preceding the current SL time slot, and the second transmission start position can be configured in symbol 810-1. The first transmission start position in time can have a higher priority than the second transmission start position in time. In other words, the first transmission start position is earlier than the second transmission start position in time. Symbols 810-2, 810-3, 810-5, 810-6, 810-7, 810-8, 810-10, 810-11, 810-12, and 810-13 can be used for PSSCH. Symbols 810-2 and 810-3 can also be used for PSDCH. Symbols 810-4 and 810-9 can be used to transmit the demodulation reference signal (DMRS). Symbol 820 is a guard symbol. PSSCH and PSCCH begin with symbol 810-2.

[0081] like Figure 8B As shown, if device 210-1 selects the first of two transmission start positions, LBT can be completed at or before the first transmission start position. For example, LBT should be completed during duration 830-1. If LBT is successful, device 210-1 can send AGC during duration 830-2 and symbol 810-1. Device 210-1 can send at least one of data or control information from symbol 810-2.

[0082] like Figure 8C As shown, if device 210-1 selects the second transmission start position out of two transmission start positions, the LBT can be completed at or before the second transmission start position. For example, device 210-1 can perform the LBT for a duration of 830-2. If device 210-1 succeeds in the LBT, it can send AGC in symbol 810-1. Device 210-1 can send at least one of the following from symbol 810-2: data or control information.

[0083] In other embodiments, for example, such as Figures 9A-9CAs shown, a first transmission start position can be configured in symbol 910-1, and a second transmission start position can be configured in symbol 910-2. The first transmission start position in time can have a higher priority than the second transmission start position in time. Symbols 910-3, 910-5, 910-6, 910-7, 910-8, 910-10, 910-11, 910-12, and 910-13 can be used for the Physical Side Link Shared Channel (PSSCH). Symbols 910-4 and 910-9 can be used to transmit the Demodulation Reference Signal (DMRS). Symbol 920 is a guard symbol. PSSCH and PSCCH begin with symbol 910-3.

[0084] like Figure 9B As shown, if device 210-1 selects the first of two transmission start positions, LBT can be completed at or before the first transmission start position. For example, LBT should be completed before symbol 910-1. If device 210-1 succeeds in LBT, device 210-1 can send AGC in symbols 910-1 and 910-2. Device 210-1 can send at least one of data or control information from symbol 910-3.

[0085] like Figure 9C As shown, if device 210-1 selects the second transmission start position out of two transmission start positions, the LBT can be completed at or before the second transmission start position. For example, device 210-1 can perform the LBT within symbol 910-1, and the LBT should be completed before symbol 910-2. If the LBT of device 210-1 is successful, there is no transmission in symbol 910-1, and device 210-1 can transmit the AGC symbol in symbol 910-2. Device 210-1 can transmit at least one of the following from symbol 910-3: data or control information.

[0086] Alternatively, as shown in the figure Figures 10A-10C As shown, two transmission start positions can be configured within symbol 100-1. The first transmission start position in time can have a higher priority than the second transmission start position in time. Symbols 100-3, 100-5, 100-6, 100-7, 100-8, 100-10, 100-11, 100-12, and 100-13 can be used for the Physical Side Link Shared Channel (PSSCH). Symbols 100-4 and 100-9 can be used to transmit the Demodulation Reference Signal (DMRS). Symbol 120 is the guard symbol. PSSCH and PSCCH begin with symbol 100-3.

[0087] like Figure 10BAs shown, if device 210-1 selects the first of two transmission start positions, LBT can be completed at or before the first transmission start position. For example, LBT should be completed before symbol 100-1. If device 210-1 successfully performs LBT, it can send AGC in symbols 100-1 and 100-2. Device 210-1 can send at least one of data or control information from symbol 100-3.

[0088] like Figure 10C As shown, if device 210-1 selects the second transmission start position out of two transmission start positions, LBT can be completed at or before the second transmission start position. For example, device 210-1 can perform LBT during duration 100-1-1. If device 210-1 successfully performs LBT, it can send AGC during duration 100-1-2 of symbol 100-1 and during symbol 100-2. Device 210-1 can start sending at least one of data or control information from symbol 100-3.

[0089] In other embodiments, for example, such as Figures 11A-11C As shown, a first transmission start position can be configured in symbol 1110-1, and a second transmission start position can be configured in symbol 1110-2. The first transmission start position in time can have a higher priority than the second transmission start position in time.

[0090] like Figure 11B As shown, if device 210-1 selects the first of two transmission start positions, LBT can be completed at or before the first transmission start position. For example, LBT should be completed before symbol 1110-1. If device 210-1 successfully performs LBT, it can transmit AGC in symbol 1110-1. Device 210-1 can transmit at least one of data or control information from symbol 1110-2. Symbols 1110-2, 1110-3, 1110-5, 1110-6, 1110-7, 1110-8, 1110-10, 1110-11, and 1110-12 can be used for the Physical Side Link Shared Channel (PSSCH). Symbols 1110-4 and 1110-9 can be used to transmit the Demodulation Reference Signal (DMRS). There is no transmission in symbol 1110-13. Symbol 1120 is a protection symbol. PSSCH and PSCCH begin with symbol 1110-2.

[0091] like Figure 11CAs shown, if device 210-1 selects the second transmission start position out of two transmission start positions, LBT can be completed at or before the second transmission start position. For example, device 210-1 can perform LBT within symbol 1110-1, and the LBT should be completed before symbol 1110-2. If device 210-1 successfully performs LBT, there is no transmission in symbol 1110-1, and device 210-1 can transmit AGC in symbol 1110-2. Device 210-1 can send at least one of the following from symbol 1110-3: data or control information. Symbols 1110-3, 1110-4, 1110-6, 1110-7, 1110-8, 1110-9, 1110-11, 1110-12, and 1110-13 can be used for the Physical Side Link Shared Channel (PSSCH). Symbols 1110-5 and 1110-10 can be used to transmit the demodulation reference signal (DMRS). No transmission is performed in symbol 1110-13. Symbol 1120 is a guard symbol. PSSCH and PSCCH begin with symbol 1110-3.

[0092] In some embodiments, such as Figures 12A-12C As shown, a first transmission start position can be configured in symbol 1210-1, and a second transmission start position can be configured in symbol 1210-2. The first transmission start position can have a higher priority in time than the second transmission start position.

[0093] like Figure 12B As shown, if device 210-1 selects the first of two transmission start positions, LBT can be completed at or before the first transmission start position. For example, LBT should be completed before symbol 1210-1. If device 210-1 successfully performs LBT, it can transmit AGC in symbol 1210-1. Device 210-1 can transmit at least one of data or control information from symbol 1210-2. Symbols 1210-2, 1210-3, 1210-5, 1210-6, 1210-7, 1210-8, 1210-10, 1210-11, 1210-12, and 1210-13 can be used for the Physical Side Link Shared Channel (PSSCH). Symbols 1210-4 and 1210-9 can be used to transmit the Demodulation Reference Signal (DMRS). Symbol 1220 is a protection symbol. PSSCH and PSCCH begin from symbol 1210-2.

[0094] like Figure 12CAs shown, if device 210-1 selects the second transmission start position out of two transmission start positions, LBT can be completed at or before the second transmission start position. For example, device 210-1 can perform LBT within symbol 1210-1, and the LBT should be completed before symbol 1210-2. If device 210-1 successfully performs LBT, there is no transmission in symbol 1210-1, and device 210-1 can transmit AGC in symbol 1210-2. Device 210-1 can send at least one of the following from symbol 1210-3: data or control information. Symbols 1210-3, 1210-4, 1210-6, 1210-7, 1210-8, 1210-9, 1210-11, 1210-12, and 1210-13 can be used for the Physical Side Link Shared Channel (PSSCH). Symbols 1210-5 and 1210-10 can be used to transmit the demodulation reference signal (DMRS). No transmission is performed in symbol 1210-13. Symbol 1220 is a guard symbol. PSSCH and PSCCH begin with symbol 1210-3.

[0095] Alternatively, to address any eventual LBT check failure (due to LBT preemption by the same system or another system), primary and secondary resources can be selected. In this case, device 210-1 can have one set of primary resources and one set of secondary resources during the sensing period.

[0096] If the sidelink transmission is the first SPS transmission, device 210-1 can select a target transmission start position with a lower priority. In subsequent sidelink transmissions, device 210-1 can select a target transmission start position with a higher priority.

[0097] In some embodiments, if device 210-1 cannot access the channel to send a sidelink transmission, device 210-1 can reselect the 3025 auxiliary resource and attempt to access the channel using the auxiliary resource. Additionally, if the sidelink transmission fails or if the sidelink transmission still fails after M attempts (primary and auxiliary resources), device 210-1 can restart resource reselection (detection) and retry the new access.

[0098] In an alternative embodiment, device 210-1 may select different starting positions for primary and secondary resources. For example, in primary resources, device 210-1 may have a lower priority starting position (e.g., for the first SPS transmission), while in secondary resources, device 210-1 may select a higher priority starting position.

[0099] In SL mode 2, as previously discussed, an earlier transmission can indicate in its SCI where the resource for the next transmission of device 210-1 will occur, thus establishing a resource reservation for future transmissions of the same device 210-1. When other devices perform sensing, these devices will be aware that there will be another transmission from the same device in a specific resource in the future. This is the principle behind establishing SPS (and non-periodic transmissions reserving resources for the next 31 time slots) in mode 2.

[0100] However, if an earlier transmission is dropped (e.g., due to reasons other than LBT, such as congestion control, higher priority UL Tx, and others), the next resource will no longer be reserved, and the device will perform its next transmission in that resource (either a new transmission or a retransmission of the original payload, indicated by the "New Data Indicator" flag in the second-stage SCI). In other words, the device performing the sensing does not receive its earlier transmissions and therefore cannot know that the device intends to transmit in a particular resource.

[0101] If a device retransmission occurs on unreserved resources, it should perform its transmission at a later start position, while a device retransmission on reserved resources can use an earlier start position.

[0102] When a device performs a new transmission, the cause of an earlier transmission blocking it can affect the starting position. For example, a blockage caused by an LBT in a previous resource allows the new transmission to use an earlier starting position in the next resource, while if the blockage is caused by something other than an LBT, the device should use a later starting position resource in the next resource.

[0103] According to embodiments of this disclosure, the use of Mode 2 on shared / unlicensed spectrum is realized, while solving the problem of unsensed (undetected) SPS transmission due to LBT failure, and making Mode 2 more robust to LBT failure due to other coexisting systems.

[0104] Figure 13 A flowchart of an example method 1300 implemented at a first device according to some example embodiments of the present disclosure is shown. For the purposes of discussion, it will be explained from the following... Figure 2 The angular description method 1300 for the device 210 shown is as follows. For example only, the first device is referred to as device 210-1.

[0105] At block 1310, device 210-1 determines a target transmission start position from a set of candidate transmission start positions in the sidelink time slot based on the access level of the sidelink transmission to be performed. In some embodiments, device 210-1 may determine the access level based on the transmission type of the sidelink transmission. Device 210-1 may select the target transmission start position from the set of candidate transmission start positions based on the access level.

[0106] In the example embodiment, if the sidelink transmission type is an ongoing sidelink semi-static scheduling transmission, device 210-1 can determine that the access level has a first priority higher than the first priority threshold. Alternatively or additionally, if the sidelink transmission type is a retransmission indicated in a previous sidelink transmission, device 210-1 can determine that the access level has a first priority higher than the first priority threshold. In this case, device 210-1 can select the earliest temporally significant target transmission start position from the set of candidate transmission start positions.

[0107] In another embodiment, if the sidelink transmission is an ongoing sidelink semi-static scheduling transmission with a fourth priority below a fourth priority threshold, device 210-1 can determine that the access level has a second priority below a first priority threshold and above a second priority threshold. Alternatively or additionally, if the sidelink transmission is a retransmission indicated in a previous sidelink transmission, having a fifth priority below a fifth priority threshold, device 210-1 can determine that the access level has a first priority threshold. In some embodiments, if the sidelink transmission is a sidelink semi-static scheduling establishment, a one-time transmission with control signaling, or a one-time transmission with a quality of service (QoS) requirement above a threshold, device 210-1 can determine that the access level has a first priority above the first priority threshold. In this case, device 210-1 can select a target transmission start position later than the earliest temporally earliest transmission start position from the set of candidate transmission start positions.

[0108] In another embodiment, if the sidelink transmission is an ongoing semi-statically scheduled sidelink transmission with a priority lower than the fourth priority threshold, device 210-1 can determine an access level of a third priority with a priority lower than the third priority threshold. Alternatively or additionally, if the sidelink transmission is a retransmission indicated in a previous sidelink transmission, having a fifth priority lower than the fifth priority threshold, device 210-1 can determine an access level of a third priority with a priority lower than the third priority threshold. In an alternative embodiment, if the sidelink transmission is a one-off transmission, and the quality of service requirement for this one-off transmission is lower than a threshold, device 210-1 can determine an access level of a third priority with a priority lower than the third priority threshold. In this case, device 210-1 can target a transmission start position that is temporally later than the earliest transmission start position in the set of candidate transmission start positions.

[0109] At block 1320, device 210-1 performs LBT on the sidelink channel prior to the target transmission start position. In some embodiments, device 210-1 may perform LBT within the first symbol of the sidelink time slot.

[0110] At box 1330, if the LBT is successful, device 210-1 performs a sidelink transmission from the target transmission start position. For example, if the LBT is performed within the first symbol of the sidelink time slot, device 210-1 may transmit a cyclic prefix for the sidelink transmission in the remainder of the first symbol, and transmit at least one of the following from the second symbol of the sidelink time slot: data or control information for the sidelink transmission.

[0111] Optionally, if device 210-1 performs LBT within the protection symbol of the sidelink time slot preceding the sidelink time slot, device 210-1 may transmit an automatic gain control symbol after the end position of the listen-before-speak. Device 210-1 may transmit at least one of data or control information for sidelink transmission from the second symbol in the sidelink time slot.

[0112] As another embodiment, if device 210-1 performs LBT within the first symbol of the sidelink time slot, device 210-1 can transmit AGC in the second symbol. Device 210-1 can also skip sidelink transmissions in the first symbol. Device 210-1 can transmit at least one of data or control information for sidelink transmissions from the third symbol of the sidelink time slot.

[0113] In other embodiments, if device 210-1 performs LBT within the first symbol of the sidelink time slot, device 210-1 may transmit an automatic gain control symbol after the end position of the listen-before-speak. Device 210-1 may transmit at least one of data or control information for sidelink transmission from the third symbol of the sidelink time slot. Alternatively, device 210-1 may transmit at least one of data or control information for sidelink transmission from the second symbol of the sidelink time slot. In this case, device 210-1 may skip sidelink transmission in the symbol preceding the protection symbol in the sidelink time slot.

[0114] In some embodiments, if device 210-1 performs LBT within the second symbol of a sidelink timeslot, device 210-1 may pre-delay the sidelink transmission delay by a predetermined time. The predetermined time offset may be any suitable value.

[0115] In some embodiments, device 210-1 may determine another target transmission start position from a set of candidate transmission start positions in the other side link timeslot for use in the other side link transmission to be performed. The other target transmission start position may have a higher priority than the target transmission start position. In other embodiments, device 210-1 may determine a primary resource set and a secondary resource set. If the side link transmission on the primary resource set fails, device 210-1 may perform a side link retransmission on the secondary resource set.

[0116] In some example embodiments, a first means (e.g., a first device) capable of performing any of the methods 1300 may include components for performing the various operations of method 1300. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit or software module. The first means may be implemented as a first device or included within a first device. In some example embodiments, the components may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause execution of the device together with the at least one processor.

[0117] In some embodiments, the apparatus includes: components for determining a target transmission start position from a set of candidate transmission start positions in a sidelink time slot based on the access level of the sidelink transmission to be performed; components for performing a listen-before-speak on the sidelink channel prior to the target transmission start position; and components for performing the sidelink transmission from the target transmission start position if the listen-before-speak is determined to be successful.

[0118] In some embodiments, the components for determining the target transmission start location include: components for determining the access level based on the transmission type of the sidelink transmission; and components for selecting the target transmission start location mapped to the access level from a set of candidate transmission start locations.

[0119] In some embodiments, the component for determining the access level based on the transmission type includes: a component for determining that the access level has a first priority higher than a first priority threshold if the transmission type is determined to be one of the following: an ongoing sidelink semi-static scheduling transmission, or a retransmission indicated in a previous sidelink transmission; the component for selecting the target transmission start position includes: a component for selecting the earliest time-wise target transmission start position from a first set of candidate transmission start positions.

[0120] In some embodiments, the component for determining the access level based on the transmission type includes: a component for determining that the access level has a second priority that is lower than a first priority threshold and higher than a second priority threshold if the transmission type is determined to be one of the following: an ongoing sidelink semi-static scheduling transmission with a fourth priority that is lower than a fourth priority threshold, a retransmission indicated in a previous sidelink link transmission, a retransmission with a fifth priority that is lower than a fifth priority threshold, a sidelink semi-static scheduling establishment, a one-time transmission with control signaling, or a one-time transmission with a service quality requirement higher than a threshold; the component for selecting a target transmission start position includes: a component for selecting a target transmission start position that is temporally later than the earliest transmission start position from a first set of candidate transmission start positions.

[0121] In some embodiments, the component for determining the access level based on the transmission type includes: a component for determining that the access level has a third priority lower than a third priority threshold if the transmission type is determined to be one of the following: an ongoing sidelink semi-static scheduling transmission having a fourth priority lower than a fourth priority threshold, a retransmission indicated in a previous sidelink link transmission, a retransmission having a fifth priority lower than a fifth priority threshold, or a one-time transmission with a service quality requirement lower than a threshold; the component for selecting the target transmission start position includes: a component for selecting the target transmission start position that is temporally later than the earliest transmission start position from a first set of candidate transmission start positions.

[0122] In some embodiments, the components for performing a listen-before-speak include: components for performing a listen-before-speak at or before the target transmission start position; components for performing a sidelink transmission include components for transmitting a cyclic prefix of the sidelink transmission in the remainder of the first symbol if the target transmission start position is determined to be within the first symbol in the sidelink time slot; and components for transmitting at least one of data or control information for the sidelink transmission to the second device from a second symbol in the sidelink time slot.

[0123] In some embodiments, the components for performing listen-before-speak include: components for performing listen-before-speak at or before the target transmission start position; components for performing sidelink transmission include components for transmitting an automatic gain control symbol after the listen-before-speak end position if the target transmission start position is determined to be within a protection symbol of another sidelink time slot preceding the sidelink time slot; and components for transmitting at least one of data or control information for sidelink transmission from a second symbol in the sidelink time slot to a second device.

[0124] In some embodiments, the components for performing listen-before-speak include: components for completing listen-before-speak at or before the target transmission start position; the components for performing sidelink transmission include: components for transmitting an automatic gain control symbol after the listen-before-speak end position if the target transmission start position is determined to be within a first symbol of the sidelink time slot; and components for transmitting at least one of data or control information for sidelink transmission from a second symbol in the sidelink time slot to a second device.

[0125] In some embodiments, the components for performing listen-before-speak include: components for performing listen-before-speak at or before the target transmission start position; the components for performing sidelink transmission include: components for transmitting an automatic gain control symbol in a first symbol and a second symbol in a sidelink time slot if the target transmission start position is determined to be within a first symbol in a sidelink time slot; and components for transmitting at least one of data or control information for sidelink transmission to a second device from a third symbol in a sidelink time slot.

[0126] In some embodiments, the components for performing listen-before-speak include: components for performing listen-before-speak at or before the target transmission start position; the components for performing sidelink transmission include: components for skipping sidelink transmission in the first symbol if the target transmission start position is determined to be within the second symbol of the sidelink time slot; components for transmitting an automatic gain control symbol in the second symbol; and components for transmitting at least one of data or control information for sidelink transmission to the second device from the third symbol of the sidelink time slot.

[0127] In some embodiments, the components for performing listen-before-speak include: components for completing listen-before-speak at or before the target transmission start position; the components for performing sidelink transmission include: components for transmitting an automatic gain control symbol after the listen-before-speak end position if the target transmission start position is determined to be within a first symbol of the sidelink time slot; and components for transmitting at least one of data or control information for sidelink transmission to a second device from a third symbol in the sidelink time slot.

[0128] In some embodiments, the components for performing listen-before-speak include: components for completing listen-before-speak at or before the target transmission start position; the components for performing sidelink transmission include: components for transmitting an automatic gain control symbol after the listen-before-speak end position if the target transmission start position is determined to be within a first symbol of the sidelink time slot; components for transmitting at least one of data or control information for sidelink transmission to a second device from a second symbol in the sidelink time slot; and components for skipping sidelink transmissions in symbols preceding the protection symbol in the sidelink time slot.

[0129] In some embodiments, the component for performing a listen-before-speak includes: a component for performing a listen-before-speak at or before the target transmission start position; the component for performing a sidelink transmission includes: a component for delaying the sidelink transmission by a predetermined time offset.

[0130] In some embodiments, the apparatus includes components for determining another target location from a set of candidate locations in the other side link time slot for transmission on the other side link, the other target location having a higher priority than the target location.

[0131] In some embodiments, the apparatus includes components for determining a primary resource set; components for determining a secondary resource set; and components for performing a sidelink retransmission on the secondary resource set if a sidelink transmission on the primary resource set is determined to have failed.

[0132] Figure 14 This is a simplified block diagram of a device 1400 suitable for implementing an example embodiment of the present disclosure. The device 1400 can be provided to implement a communication device, such as... Figure 1 The first device 110 or the second device 120 shown. As shown, device 1400 includes one or more processors 1410, one or more memories 1420 coupled to processor 1410, and one or more communication modules 1440 coupled to processor 1410.

[0133] Communication module 1440 is used for bidirectional communication. Communication module 1440 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface can represent any interface necessary for communication with other network elements. In some example embodiments, communication module 1440 may include at least one antenna.

[0134] Processor 1410 can be any type suitable for a local technology network and may include one or more of the following as non-limiting examples: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), and processor based on a multi-core processor architecture. Device 1400 may have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0135] Memory 1420 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 1424, electrically programmable read-only memory (EPROM), flash memory, hard disk, optical disc (CD), digital video disc (DVD), optical disc, laser disc, and other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 1422 and other volatile memories that do not persist during power-off periods.

[0136] Computer program 1430 includes computer-executable instructions that are executed by an associated processor 1410. Program 1430 may be stored in a memory such as ROM 1424. Processor 1410 can perform any suitable actions and processes by loading program 1430 into RAM 1422.

[0137] Some example embodiments of this disclosure can be implemented by means of program 1430, enabling device 1400 to perform as described in the reference. Figures 3 to 13 Any process discussed in this disclosure. Exemplary embodiments of this disclosure may also be implemented by hardware or by a combination of software and hardware.

[0138] In some example embodiments, program 1430 may be tangibly contained in a computer-readable medium, which may be included in device 1400 (such as in memory 1420) or other storage devices accessible to device 1400. Device 1400 may load program 1430 from the computer-readable medium into RAM 1422 for execution. The computer-readable medium may include any type of tangible non-volatile storage, such as ROM, EPROM, flash memory, hard disk, CD, DVD, and other magnetic and / or optical storage. Figure 15 An example of a computer-readable medium 1500 in the form of an optical storage disk is shown. A program 1430 is stored on the computer-readable medium.

[0139] Generally, the various embodiments of this disclosure can be implemented in hardware or special-purpose circuitry, software, logic, or any combination thereof. Some aspects can be implemented in hardware, while others can be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are shown and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, special-purpose circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0140] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as computer-executable instructions included in a program module, which execute in a device on a target physical or virtual processor to perform the above-referenced... Figures 2 to 5 Any of the methods described herein. Typically, a program module includes routines, programs, libraries, objects, classes, components, data types, etc., that perform a specific task or implement a specific abstract data structure. The functionality of a program module can be combined or split among program modules as needed in various example embodiments. The machine-executable instructions used for a program module can execute on a local or distributed device. In a distributed device, a program module can reside on both local and remote storage media.

[0141] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, it causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0142] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0143] Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of computer-readable storage media include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0144] Furthermore, although operations are described in a specific order, this should not be construed as requiring such operations to be performed in the specific order shown or in a sequential order, or to perform all shown operations to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these details should not be construed as limiting the scope of this disclosure, but rather as descriptions of features specific to particular embodiments. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination.

[0145] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms for implementing the claims.

Claims

1. A first device, comprising: At least one processor; as well as At least one memory, including computer program code; The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to: Based on the access level of the sidelink transmission to be performed, a target transmission start position is determined from a set of candidate transmission start positions in the sidelink time slots, wherein the access level is determined based on the transmission type of the sidelink transmission, and the transmission type is associated with at least one of the following: Is the sidelink transmission an ongoing sidelink semi-static scheduling (SL SPS) transmission? Is the sidelink transmission a retransmission indicated in a previous SL SPS transmission? Is the sidelink transmission the first SL SPS transmission? Is the sidelink transmission a one-time transmission with control signaling? as well as Quality of Service (QoS) requirements for one-time transmissions of user plane services; Listen before speaking on the side link channel before the target transmission start position is reached; as well as If the "listen first, speak later" procedure is confirmed to be successful, the sidelink transmission is executed from the target transmission start position.

2. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to determine the target transmission start position by: The access level is determined based on the transmission type of the side link transmission; and Select the target transmission start position mapped to the access level from the set of candidate transmission start positions.

3. The first device of claim 2, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to determine the access level based on the transmission type by: If the transmission type is determined to be one of the following, then the access level is determined to have a first priority higher than the first priority threshold: Ongoing SL SPS transfer, or Retransmissions indicated in previous sidelink transmissions; and The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to select the target transmission start location by: Select the earliest time-based target transmission start position from the set of candidate transmission start positions.

4. The first device of claim 2, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to determine the access level based on the transmission type: If the transmission type is determined to be one of the following, then the access level is determined to have a second priority that is lower than the first priority threshold and higher than the second priority threshold: An ongoing SL SPS transfer with a priority level below the fourth priority threshold. A retransmission indicated in a previous sidelink transmission, the retransmission having a fifth priority below the fifth priority threshold. SL SPS setup, One-time transmission with control signaling, or One-time transmissions with service quality requirements exceeding a threshold; and The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to select the target transmission start location by: The target transmission start position is selected from the set of candidate transmission start positions that is later in time than the earliest transmission start position.

5. The first device of claim 2, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to determine the access level based on the transmission type: If the transmission type is determined to be one of the following, then the access level is determined to have a third priority lower than the third priority threshold: An ongoing SL SPS transfer with a priority level below the fourth priority threshold. A retransmission indicated in a previous sidelink transmission, the retransmission having a fifth priority below the fifth priority threshold. There are one-time transmissions with service quality requirements below a threshold; and The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to select the target transmission start location by: The target transmission start position is selected from the set of candidate transmission start positions that is later in time than the earliest transmission start position.

6. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak instruction by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: If the target transmission start position is determined to be within the first symbol of the side link time slot, a cyclic prefix of the side link transmission is transmitted in the remaining portion of the first symbol; and At least one of the data or control information used for the sidelink transmission is transmitted from the second symbol in the sidelink time slot to the second device.

7. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak instruction by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: If the target transmission start position is determined to be within the protection symbol of another side link time slot preceding the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; and At least one of the data or control information used for the sidelink transmission is transmitted from the second symbol in the sidelink time slot to the second device.

8. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak instruction by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: If the target transmission start position is determined to be within the first symbol of the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; and At least one of the data or control information used for the sidelink transmission is transmitted from the second symbol in the sidelink time slot to the second device.

9. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak instruction by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: If the target transmission start position is determined to be within the first symbol of the side link time slot, then... Automatic gain control symbols are transmitted in the first and second symbols of the side link time slot; and At least one of the data or control information used for the sidelink transmission is transmitted from the third symbol in the sidelink time slot to the second device.

10. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak statement by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: If the target transmission start position is determined to be within the second symbol of the side link time slot, Skip the sidelink transmission in the first symbol; The automatic gain control symbol is transmitted in the second symbol; as well as At least one of the data or control information used for the sidelink transmission is transmitted from the third symbol in the sidelink time slot to the second device.

11. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak statement by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: If the target transmission start position is determined to be within the first symbol of the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; and At least one of the data or control information used for the sidelink transmission is transmitted from the third symbol in the sidelink time slot to the second device.

12. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak statement by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: If the target transmission start position is determined to be within the first symbol of the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; Transmit at least one of data or control information for the sidelink transmission from the second symbol in the sidelink time slot to the second device; and Skip the side link transmission in the symbol preceding the protection symbol in the side link time slot.

13. The first device of claim 1, wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the first device to perform the listen-before-speak instruction by: The "listen first, speak later" procedure is completed at or before the target transmission start position. The at least one memory and the computer program code are configured, together with the at least one processor, to enable the first device to perform the sidelink transmission by: The side link transmission delay is offset by a predetermined time.

14. The first device of claim 1, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, enable the first device to: Another target location is determined from a set of candidate locations in the other link time slot for transmission on the other link, the other target location having a higher priority than the original target location.

15. The first device of claim 1, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, enable the first device to: Identify the primary resource set; Determine the set of auxiliary resources; If it is determined that the sidelink transmission on the primary resource set has failed, a sidelink retransmission is performed on the secondary resource set.

16. The first device according to any one of claims 1-15, wherein the first device is a terminal device and the second device is another terminal device.

17. A method for communication, comprising: At the first device, a target transmission start position is determined from a set of candidate transmission start positions in the sidelink time slots based on the access level of the sidelink transmission to be performed, wherein the access level is determined based on the transmission type of the sidelink transmission, the transmission type being associated with at least one of the following: Is the sidelink transmission an ongoing sidelink semi-static scheduling (SL SPS) transmission? Is the sidelink transmission a retransmission indicated in a previous SL SPS transmission? Is the sidelink transmission the first SL SPS transmission? Is the sidelink transmission a one-time transmission with control signaling? as well as Quality of Service (QoS) requirements for one-time transmissions of user plane services; Listen before speaking on the side link channel before the target transmission start position is reached; as well as If the "listen first, speak later" procedure is confirmed to be successful, the sidelink transmission is executed from the target transmission start position.

18. The method of claim 17, wherein determining the target transmission start position comprises: The access level is determined based on the transmission type of the side link transmission; as well as Select the target transmission start position mapped to the access level from the set of candidate transmission start positions.

19. The method of claim 18, wherein determining the access level based on the transmission type comprises: If the transmission type is determined to be one of the following, then the access level is determined to have a first priority higher than the first priority threshold: Ongoing SL SPS transfer, or Retransmissions indicated in previous sidelink transmissions; as well as The selection of the target transmission start position includes: Select the earliest time-based target transmission start position from the set of candidate transmission start positions.

20. The method of claim 18, wherein determining the access level based on the transmission type comprises: If the transmission type is determined to be one of the following, then the access level is determined to have a second priority that is lower than the first priority threshold and higher than the second priority threshold: An ongoing SL SPS transfer with a priority level below the fourth priority threshold. A retransmission indicated in a previous sidelink transmission, the retransmission having a fifth priority below the fifth priority threshold. SL SPS setup, One-time transmission with control signaling, or One-time transmissions with service quality requirements exceeding a threshold; as well as The selection of the target transmission start position includes: The target transmission start position is selected from the set of candidate transmission start positions that is later in time than the earliest transmission start position.

21. The method of claim 18, wherein determining the access level based on the transmission type comprises: If the transmission type is determined to be one of the following, then the access level is determined to have a third priority lower than the third priority threshold: An ongoing SL SPS transfer with a priority level below the fourth priority threshold. A retransmission indicated in a previous sidelink transmission, the retransmission having a fifth priority below the fifth priority threshold. One-time transmissions with service quality requirements below the threshold; as well as The selection of the target transmission start position includes: The target transmission start position is selected from the set of candidate transmission start positions that is later in time than the earliest transmission start position.

22. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: If the target transmission start position is determined to be within the first symbol of the side link time slot, the cyclic prefix of the side link transmission is transmitted in the remaining portion of the first symbol; as well as At least one of the data or control information used for the sidelink transmission is transmitted from the second symbol in the sidelink time slot to the second device.

23. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: If the target transmission start position is determined to be within the protection symbol of another side link time slot preceding the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; as well as At least one of the data or control information used for the sidelink transmission is transmitted from the second symbol in the sidelink time slot to the second device.

24. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: If the target transmission start position is determined to be within the first symbol of the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; as well as At least one of the data or control information used for the sidelink transmission is transmitted from the second symbol in the sidelink time slot to the second device.

25. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: If the target transmission start position is determined to be within the first symbol of the side link time slot, then... Automatic gain control symbols are transmitted in the first and second symbols of the side link time slot; as well as At least one of the data or control information used for the sidelink transmission is transmitted from the third symbol in the sidelink time slot to the second device.

26. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: If the target transmission start position is determined to be within the second symbol of the side link time slot, Skip the sidelink transmission in the first symbol; The automatic gain control symbol is transmitted in the second symbol; and At least one of the data or control information used for the sidelink transmission is transmitted from the third symbol in the sidelink time slot to the second device.

27. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: If the target transmission start position is determined to be within the first symbol of the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; as well as At least one of the data or control information used for the sidelink transmission is transmitted from the third symbol in the sidelink time slot to the second device.

28. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: If the target transmission start position is determined to be within the first symbol of the side link time slot, an automatic gain control symbol is transmitted after the listen-before-speak end position; Transmit at least one of data or control information for the sidelink transmission from the second symbol in the sidelink time slot to the second device; and Skip the side link transmission in the symbol preceding the protection symbol in the side link time slot.

29. The method of claim 17, wherein performing the "listen before speaking" action comprises: The "listen first, speak later" procedure is completed at or before the target transmission start position. The sidelink transmission includes: The side link transmission delay is offset by a predetermined time.

30. The method of claim 17, further comprising: Another target location is determined from a set of candidate locations in the other link time slot for transmission on the other link, the other target location having a higher priority than the original target location.

31. The method of claim 17, further comprising: Identify the primary resource set; Determine the set of auxiliary resources; If it is determined that the sidelink transmission on the primary resource set has failed, a sidelink retransmission is performed on the secondary resource set.

32. The method according to any one of claims 17-31, wherein the first device is a terminal device and the second device is another terminal device.

33. An apparatus for communication, comprising components for performing at least the method according to any one of claims 17-32.

34. A computer-readable medium comprising program instructions for causing a device to perform the method according to any one of claims 17-32.

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