Method and apparatus for detecting a burst of sidelink transmissions over an unlicensed spectrum

Abstract

Embodiments of this disclosure relate to methods and apparatus for detecting sidelink transmission bursts on unlicensed spectrum. According to an embodiment of this disclosure, a method for wireless communication performed by a user equipment (UE) includes: generating a sequence; and transmitting the sequence at the start of a sidelink burst on a carrier, starting from a first candidate position in a set of candidate positions in a first time slot, wherein the sequence spans a predetermined number of consecutive symbols in the time domain and the sidelink burst is transmitted continuously in the time domain without any gaps.

Description

Technical Field

[0001] Embodiments of this disclosure relate to wireless communication technology, and more specifically, to methods and apparatus for detecting sidelink transmission bursts on unlicensed spectrum. Background Technology

[0002] In New Radio (NR) communication systems, a Transmitting User Equipment (UE) (hereinafter referred to as "Tx UE") can send sidelink transmissions to a specific Receiving UE (hereinafter referred to as "Rx UE") in unicast mode, to a group of Rx UEs in multicast mode, or to a range of Rx UEs in broadcast mode. When unlicensed spectrum is used for sidelink transmissions, a channel access procedure (also known as a "listen-before-tell" (LBT) procedure is required before any sidelink transmission to ensure fair coexistence with other radio systems. In the LBT procedure, the UE performs an energy detection on the channel. If the detected energy is below a predefined threshold, the channel is considered empty and available for transmission, and the LBT procedure succeeds. Only when the LBT procedure succeeds can the UE begin transmitting on the channel and occupy the channel until the Maximum Channel Occupancy Time (MCOT); otherwise, the UE cannot begin transmitting and needs to continue executing another LBT procedure until a successful LBT procedure is completed.

[0003] On the other hand, a sidelink UE can monitor the Physical Sidelink Control Channel (PSCCH), which carries Sidelink Control Information (SCI) containing time-frequency resource information for scheduling the associated Physical Sidelink Shared Channel (PSSCH). When unlicensed spectrum is used for sidelink transmission, if the channel is occupied by other wireless access technologies (e.g., WiFi) or other nearby operators, or if the channel is occupied by other UEs and the transmission is not of interest to the sidelink UE, then the sidelink UE does not need to blindly detect the SCI in every time slot. Therefore, there is a need to develop a method that enables the sidelink UE to know who is occupying the channel and whether the ongoing transmission is of interest to the sidelink UE without detecting or decoding the SCI in order to save power. Summary of the Invention

[0004] According to embodiments of this disclosure, a method for wireless communication performed by a user equipment (UE) may include: generating a sequence; and transmitting the sequence at the start of a sidelink burst on a carrier, starting from a first candidate position in a set of candidate positions in a first time slot, wherein the sequence spans a predetermined number of consecutive symbols in the time domain and the sidelink burst is transmitted continuously in the time domain without any gaps.

[0005] According to another embodiment of this disclosure, a method for wireless communication performed by a UE may include: detecting a sequence on a carrier at a first candidate location in a set of candidate locations in a time slot, wherein the sequence spans a predetermined number of consecutive symbols in a time domain; and receiving a sidelink transmission from the first candidate location in the time slot in response to detecting the sequence at the first candidate location.

[0006] According to another embodiment of this disclosure, an apparatus may include: at least one non-transitory computer-readable medium having computer-executable instructions stored thereon; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry, and the at least one transmitting circuitry. The computer-executable instructions may cause the at least one processor to perform a method according to any embodiment of this disclosure.

[0007] Details of one or more examples are set forth in the accompanying drawings and the following description. Other features, objectives, and advantages will become apparent from the description, drawings, and claims. Attached Figure Description

[0008] To illustrate how the advantages and features of this disclosure can be obtained, the description of this disclosure is presented with reference to specific embodiments of the disclosure illustrated in the accompanying drawings. These drawings depict only exemplary embodiments of the disclosure and are therefore not intended to limit the scope of the disclosure.

[0009] Figure 1 Illustrated schematic diagrams of wireless communication systems according to some embodiments of the present disclosure;

[0010] Figure 2 Examples of interleaved resource block configurations according to some embodiments of this disclosure are described;

[0011] Figure 3 An exemplary flowchart illustrating a method for detecting sidelink transmission bursts on unlicensed spectrum according to some embodiments of this disclosure;

[0012] Figure 4 This describes an example of transmitting a predefined sequence only at the start of a sidelink burst, according to some embodiments of this disclosure;

[0013] Figure 5 This describes an example of transmitting a predefined sequence in each time slot of a sidelink burst according to some embodiments of this disclosure;

[0014] Figure 6 An exemplary flowchart illustrating a method for detecting sidelink transmission bursts on unlicensed spectrum according to some embodiments of this disclosure;

[0015] Figure 7Exemplary block diagrams illustrating devices according to some embodiments of the present disclosure; and

[0016] Figure 8 An exemplary block diagram illustrating another device according to some embodiments of the present disclosure. Detailed Implementation

[0017] The detailed description of the accompanying drawings is intended to illustrate the presently preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure may be practiced. It should be understood that the same or equivalent functionality may be accomplished through different embodiments that are intended to be covered within the spirit and scope of the present disclosure.

[0018] In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments, including examples of programming, software modules, network transactions, database structures, hardware modules, hardware circuits, etc. However, those skilled in the art will recognize that embodiments can be practiced without one or more of these specific details or using other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the embodiments.

[0019] Reference will now be made in detail to some embodiments of this disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided within specific network architectures and new service scenarios, such as 3GPP 5G and 3GPP Long Term Evolution (LTE). Those skilled in the art will appreciate that all embodiments of this disclosure are applicable to similar technical problems as network architectures and new service scenarios develop; furthermore, the terminology used in this disclosure may change without affecting the principles of this disclosure.

[0020] Figure 1 A schematic diagram illustrating a wireless communication system 100 according to some embodiments of this application.

[0021] like Figure 1 As shown, the wireless communication system 100 may include a base station (e.g., BS 120) and several UEs 110 (e.g., UE 110a, UE 110b, and UE 110c). Although in Figure 1 The description depicts a specific number of UEs 110 and one BS 120, but it is understood that the wireless communication system 100 may include more BSs and more or fewer UEs outside the coverage area of ​​the BS.

[0022] The UE and BS can support communication based on, for example, 3G, LTE, LTE-A, NR, or other suitable protocols. For example, BS 102 may include an eNB or gNB. UE 110a, UE 110b, or UE 110c may include (e.g., but not limited to) computing devices, wearable devices, mobile devices, IoT (Internet of Things) devices, vehicles, etc. Those skilled in the art will understand that the terminology described in this disclosure may change as technology develops and advances, but this should not affect or limit the principles and spirit of this disclosure.

[0023] BS 120 may define one or more cells, and each cell may have a coverage area 130. In the exemplary wireless communication system 100, some UEs (e.g., UE 110a and UE 110b) are within the coverage area of ​​BS 120, and BS 120 may not be... Figure 1 The specific base station 120 shown can be any of the base stations 120 in the wireless communication system, and some UEs (e.g., UE110c) are outside the coverage of BS 120. For example, in the case where the wireless communication system includes two BS 120s, UE110a being within the coverage of either of the two BS 120s means that UE110a is within the coverage of BS 120 in the wireless communication system (i.e., within the coverage); and UE110a being outside the coverage of either BS 120 means that UE110a is outside the coverage of BS 120 in the wireless communication system (i.e., outside the coverage).

[0024] Still referencing Figure 1 UE 110a and UE 110b can be connected via, for example, a Uu link (from... Figure 1 (Indicated by the dashed arrow in the diagram) communicates with BS120. UE 110a, UE 110b, and UE 110c can communicate via a side link (from...). Figure 1 (Indicated by solid arrows in the diagram) UEs communicate with each other and can form UE groups. During sidelink communication, Tx UEs can transmit signaling, data, or both to Rx UEs. For example, refer to... Figure 1 A Tx UE (e.g., UE 110a) can transmit data to an Rx UE (e.g., UE 110b or UE 110c).

[0025] BS (e.g.) Figure 1 BS 120) and UE (e.g. Figure 1UEs 110a, 110b, and 110c can operate on both licensed and unlicensed spectrum. For example, unlicensed spectrum can be a carrier frequency of approximately 6 GHz or 60 GHz. NR-U (NR System Access over Unlicensed Spectrum) operating bandwidth can be an integer multiple of 20 MHz. For bandwidths greater than 20 MHz, such as 40 MHz, 60 MHz, 80 MHz, or 100 MHz, the carrier bandwidth can be divided into subbands, each with a 20 MHz bandwidth and indexable.

[0026] When unlicensed spectrum is used for sidelink transmissions between UEs (e.g., between a Tx UE and an Rx UE), the Tx UE is required to perform an LBT procedure before performing any sidelink transmissions. The LBT procedure is performed based on energy detection in each sensing slot. Specifically, if the energy detected on a channel in a sensing slot is below an energy detection threshold, the channel is considered empty, interference-free, or available in that sensing slot; otherwise, the channel is considered occupied or unavailable in that sensing slot. For Type 1 channel access procedures, also known as "LBT Category 4 or LBT Cat.4 procedures," energy detection typically needs to be performed over a range of several to hundreds of sensing slots. A random backoff counter is selected from the contention window at the start of the LBT Cat.4 procedure. The random backoff counter is decremented by 1 whenever the Tx UE detects an empty channel in a sensing slot. When the random backoff counter decrements to zero, the channel is considered available and the LBT Cat.4 procedure is successful. Next, the Tx UE can determine that the Channel Occupied Time (COT) is no greater than the MCOT, and begin sidelink transmission on the channel within the COT. In the LBT Cat.4 procedure, the contention window is continuously updated based on Hybrid Automatic Repeat Request (HARQ)-Acknowledgement (ACK) feedback from the Rx UE. More detailed Type 1 channel access procedures are specified in the 3GPP standard document TS37.213.

[0027] Radio transmissions on unlicensed spectrum must comply with regulations governing the country or region where the wireless communication device (e.g., UE) is located. The design of uplink waveforms for the NR-U Physical Uplink Shared Channel (PUSCH) and Physical Uplink Control Channel (PUCCH) must meet these regulatory requirements for unlicensed spectrum. These requirements primarily encompass two aspects:

[0028] (1) Occupied Channel Bandwidth (OCB): The bandwidth containing 99% of the signal power should be between 80% and 100% of the declared nominal channel bandwidth; and

[0029] (2) Maximum power spectral density (PSD) with a resolution bandwidth of 1 MHz (e.g., 10 dBm / MHz).

[0030] The two requirements above indicate that a small portion of the signal occupying the channel bandwidth cannot be transmitted at the UE with maximum available power due to PSD and OCB constraints.

[0031] To meet regulatory requirements, interleaved waveforms are used as uplink waveforms for unlicensed spectrum. For NR-U, interleaved waveforms can be used to achieve power enhancement under PSD constraints and meet the regulatory requirements defined for OCB. Therefore, NRUL transmissions also employ interleaved transmission.

[0032] In NR systems, multiple interleavings within a resource block (RB) are defined in a common resource block (CRB) based on the subcarrier spacing. The total number of interleavings distributed across the carrier bandwidth can be based solely on the subcarrier spacing, regardless of the carrier bandwidth. The subcarrier spacing in an NR system can be 15 × 2. n kHz, where n is an integer. The subcarrier spacing for frequency range 1 (FR1) can be 15 kHz, 30 kHz, or 60 kHz, and different subcarrier spacing values ​​can support different maximum bandwidths. In some instances, for a carrier with a 15 kHz subcarrier spacing, there can be 10 interleavings on the carrier. In some instances, for a carrier with a 30 kHz subcarrier spacing, there can be 5 interleavings on the carrier. In some instances, for a carrier with a 60 kHz subcarrier spacing, there can be 2 or 3 interleavings on the carrier. It should be understood that the number of interleavings (e.g., 10 interleavings for a carrier with a 15 kHz subcarrier spacing, or 5 interleavings for a carrier with a 30 kHz subcarrier spacing) is for illustrative purposes only and should not be construed as limiting the embodiments of this disclosure.

[0033] The number of redundancies (RBs) in each interleaving on a carrier can depend on the carrier bandwidth. For example, when the carrier bandwidth is 20 MHz and the subcarrier spacing is 15 kHz, each of 10 interleavings can contain 10 or 11 RBs. When the carrier bandwidth is 20 MHz and the subcarrier spacing is 30 kHz, each of 5 interleavings can contain 10 or 11 RBs. It should be understood that the number of RBs is for illustrative purposes only and should not be construed as a limitation on the embodiments of this disclosure. For carrier bandwidths greater than 20 MHz, the same spacing between consecutive RBs in the interleaving is maintained for all interleavings, regardless of the carrier bandwidth. In other words, the number of RBs in each interleaving can depend on the carrier bandwidth. Maintaining the same interleaving spacing with increasing bandwidth is a straightforward and simple way to scale the interleaving design from 20 MHz to a wider bandwidth.

[0034] Figure 2Examples of interleaved resource block configuration 200 for a 15 kHz subcarrier spacing are illustrated according to some embodiments of this disclosure. It should be understood that configuration 200 is for illustrative purposes only and should not be construed as a limitation on the embodiments of this disclosure.

[0035] like Figure 2 As shown in the diagram, the carrier bandwidth can be divided into RBs. For illustrative purposes, Figure 2 Only the RBs contained in the carrier bandwidth are shown (e.g., in Figure 2 This refers to a portion of the RBs (represented by reference numbers 2000 to 2035). Those skilled in the art can easily determine the number of RBs contained in a given carrier bandwidth.

[0036] As mentioned above, the number of interleavings distributed within the carrier bandwidth can be based solely on the subcarrier spacing and is independent of the carrier bandwidth. Figure 2 In this example, the carrier bandwidth RB is divided into 10 interleaved intervals (corresponding to a 15kHz subcarrier spacing), which in Figure 2 The reference numbers 210, 211, 212, 213, 214, 215, 216, 217, 218 and 219 are used respectively.

[0037] Each of the 10 interleavings can contain RBs that are uniformly spaced in the frequency domain. The number of RBs in each of the 10 interleavings can depend on the carrier bandwidth. For example... Figure 2 As shown, the interleaving represented by component symbol 210 can include RB2000, RB 2010, RB 2020, RB 2030, etc.; the interleaving represented by component symbol 211 can include RB2001, RB 2011, RB2021, RB 2031, etc.; and the interleaving represented by component symbol 219 can include RB 2009, RB 2019, RB 2029, etc. RB2000 to RB 2035 can be indexed along the frequency axis from "0" to "35", and interleavings 210 to 219 can be indexed from "0" to "9".

[0038] Similarly, sidelink transmission can also employ interleaved transmission. For example, one or more of interleaved 210 to 219 can be assigned for sidelink transmission on unlicensed spectrum.

[0039] For sidelink transmissions, two resource allocation modes have been specified since LTE Rel-12 device-to-device (D2D) communication, and this has been further extended to LTE / NR vehicle-to-everything (V2X) communication. Resource allocation based on base station (e.g., gNB or eNB) scheduling is called Mode 1, and resource allocation based on UE autonomous selection is called Mode 2.

[0040] For either Mode 1 or Mode 2, the SCI is transmitted on the PSCCH, which contains time-frequency resource information for the associated PSSCH scheduling. The SCI and associated PSSCH are transmitted unicast from a Tx UE to a specific Rx UE, multicast to a group of Rx UEs, or broadcast to any other UE within a range.

[0041] In Mode 1, the precise resources used for sidelink transmission are assigned by the base station via dynamic scheduling or configuration authorization. In Mode 2, the UE needs to perform resource sensing by decoding all SCIs transmitted in the SCI resource pool to fully understand resource reservation information. After sensing, the UE can identify available resources and then randomly select the required resources from the available resources.

[0042] When unlicensed spectrum is used for sidelink transmissions, from the UE's perspective, if the channel is occupied by other wireless access technologies (e.g., WiFi) or other nearby operators, or if the channel is occupied by another UE and the transmission is not of interest to the UE, then the UE does not need to blindly detect SCIs on the channel in every time slot. Such blind detection consumes the UE's battery power. The embodiments of this disclosure described below provide an exemplary solution for detecting sidelink transmission bursts on unlicensed spectrum, enabling the sidelink UE to avoid unnecessary channel access procedures or blindly detect ongoing transmissions that are not of interest to the sidelink UE, thereby saving the sidelink UE's power.

[0043] Figure 3 This document describes an exemplary flowchart of a method 300 for detecting sidelink transmission bursts on unlicensed spectrum according to some embodiments of the present disclosure. Method 300 can be performed by a Tx UE or other means with similar functionality.

[0044] like Figure 3 As shown, in step 302, the Tx UE can generate a sequence. The sequence is transmitted at the start of a sidelink transmission (also a sidelink burst) on the carrier and is predefined for other UEs (e.g., Rx UEs) to determine whether the sidelink transmission is an NR sidelink transmission or a transmission using other radio access technologies (e.g., WiFi) or whether the sidelink transmission is a sidelink unicast, multicast, or broadcast communication of interest.

[0045] To maintain orthogonality across the entire frequency domain, the sequence is relative to the carrier's CRB 0 (e.g., Figure 2 The subcarrier 0 of RB 2000 is generated and can occupy all subcarriers on the carrier. In the time domain, the sequence can occupy a predetermined number of consecutive symbols.

[0046] In some embodiments of this disclosure, the predetermined number is based on the subcarrier spacing (SCS) value and the automatic gain control (AGC) retuning time. For example, the first symbol of a sidelink transmission is typically used for AGC purposes and does not carry valid user data. When the AGC retuning time is in the range of 20 to 30 μs, AGC retuning will not take up the entire symbol duration in the case of a 15 or 30 kHz SCS. In this case, the sequence can only occupy the first symbol of the sidelink transmission. That is, the predetermined number is 1. However, in the case of a 60 or 120 kHz or even higher SCS, AGC retuning may not be completed within the duration of the first symbol. For reliability purposes, the sequence should occupy more than one symbol of the sidelink transmission so that it can be correctly detected by other UEs (e.g., RxUEs). That is, the predetermined number is more than 1. The predetermined number can be configured via Radio Resource Control (RRC) signaling or predefined in the standard based on the carrier's SCS value and AGC retuning time.

[0047] Therefore, the length of the sequence is equal to the total number of subcarriers of the carrier multiplied by a predetermined number. In some embodiments of this disclosure, the sequence is cyclically mapped from the lowest to the highest subcarrier of the carrier in a frequency-first manner over each of a predetermined number of consecutive symbols. Assuming there are a total of N subcarriers on the carrier and the predetermined number is M, then the sequence length is equal to N*M. The sequence can be labeled as {a0, a1, a2, a3, a4, a5, a6, a7, a8, ..., a...} N-1 ,a N ,a N+1 ,…,a N*M-1 The sequence is cyclically mapped on each of a predetermined number of consecutive symbols in a frequency-first manner. This means that a0 is mapped on subcarrier 0 of the first symbol, a1 is mapped on subcarrier 1 of the first symbol, a2 is mapped on subcarrier 2 of the first symbol, a3 is mapped on subcarrier 3 of the first symbol, a4 is mapped on subcarrier 4 of the first symbol, and so on, until all subcarriers of the first symbol have been mapped. Then, mapping a0 on subcarrier 0 of the second symbol begins. N Mapping a on subcarrier 1 of the second symbol N+1 Mapping a on subcarrier 2 of the second symbol N+2 This process continues until all subcarriers of the second symbol have been mapped, and then this mapping is repeated on the remaining symbols until all subcarriers of all M symbols have been mapped. It should be understood that in this example, the length of the sequence is for illustrative purposes only and should not be construed as a limitation on the embodiments of this disclosure.

[0048] In some embodiments of this disclosure, the length of the sequence is equal to the total number of subcarriers of the carrier, and the sequence is repeatedly mapped from the lowest to the highest subcarrier of the carrier over each of a predetermined number of consecutive symbols. That is, the same sequence is mapped over each symbol. For example, assuming there are a total of N subcarriers on the carrier, then the sequence length is equal to N. The sequence can be labeled as {a0, a1, a2, a3, a4, a5, a6, a7, a8, ..., a...} N-1 The sequence is repeatedly mapped on each of a predetermined number of consecutive symbols. This means mapping a0 on subcarrier 0 of the first symbol, a1 on subcarrier 1 of the first symbol, a2 on subcarrier 2 of the first symbol, a3 on subcarrier 3 of the first symbol, a4 on subcarrier 4 of the first symbol, and so on, until all subcarriers of the first symbol have been mapped. Then, mapping a0 on subcarrier 0 of the second symbol, a1 on subcarrier 1 of the second symbol, a2 on subcarrier 2 of the second symbol, and so on, until all subcarriers of the second symbol have been mapped. This mapping is then repeated on the remaining symbols until all subcarriers of all predetermined number of symbols have been mapped. It should be understood that, in this example, the length of the sequence is for illustrative purposes only and should not be construed as a limitation on the embodiments of this disclosure.

[0049] Sequences can be generated in different ways depending on the application.

[0050] According to some embodiments of this disclosure, the sequence can be predefined in the standard as a common sequence for radio access technologies. For example, the sequence can be used to indicate whether a transmission uses 3GPP radio technology or WiFi. In embodiments, an all-"1" sequence can be generated for NR sidelink transmissions. It should be understood that other predefined sequences can also be used.

[0051] According to some embodiments of this disclosure, the sequence can be predefined in a standard as a common sequence for sidelink transmissions between multiple cells. Therefore, the UE can detect sequences in transmissions from other UEs in neighboring cells. For example, the sequence can be generated according to the following equation and passed through c. init =1010 for initialization. Other values ​​not less than 1008 can also be used for initialization.

[0052]

[0053] The sequence r(m) has a length M, m = 0, 1, ..., M-1, and the pseudo-random sequence c(m) is defined by the length -31 golden sequence as follows.

[0054] The output sequence c(n) has a length M PN where n = 0, 1, ..., M PN-1, and is defined as follows

[0055] c(n)=(x1(n+N C )+x2(n+N C ))mod2

[0056] x1(n+31)=(x1(n+3)+x1(n))mod2

[0057] x2(n+31)=(x2(n+3)+x2(n+2)+x2(n+1)+x2(n))mod2

[0058] Where N C =1600 and the first m-sequence x1(n) should be initialized with x1(0) = 1, x1(n) = 0, n = 1, 2, ..., 30. The initialization of the second m-sequence x2(n) is determined by... Identification. It should be understood that as long as the sequence is common to sidelink transmissions between multiple cells, it can be generated using other methods.

[0059] According to some embodiments of this disclosure, the sequence can be predefined in the standard as a side-link cell-specific sequence. Therefore, the UE can detect sequences in transmission from other UEs within the same cell but cannot identify sequences in transmission from other UEs in neighboring cells. For example, the sequence can be generated according to the above equation and passed through c. init = Cell identifier (ID) initialization. For inter-cell interference randomization, the sequence can be initialized by an ID configured at a higher layer, such as N. ID ∈{0,1,…,65535}.

[0060] According to some embodiments of this disclosure, the sequence can be predefined in the standard as a sidelink Tx UE-specific sequence. Therefore, a UE that is not interested in ongoing unicast from a Tx UE cannot recognize the sequence in a transmission from the Tx UE, allowing the UE to skip decoding the SCI or PSCCH in such transmissions. For example, the sequence can be generated according to the above equation and passed through c init = Initialize the ID of Tx UE. The ID can be the source ID of Tx UE.

[0061] According to some embodiments of this disclosure, sequences are predefined in the standard as sidelink group-specific sequences. Therefore, UEs uninterested in ongoing multicast communication cannot recognize sequences in transmissions from any Tx UE in the group, allowing the UE to skip decoding SCI or PSCCH in such transmissions. For example, sequences can be generated according to the above equation and passed through c init =Group ID initialization. This group ID is indicated or configured during the establishment of multicast between UEs in the same group.

[0062] According to some embodiments of this disclosure, sequences are predefined in the standard as sidelink interleaving-specific sequences. Since SCIs from a Tx UE are transmitted only in one interleaving due to the large space of an interleaving, interleaving-specific sequences can be designed for associated SCI transmissions. Sequences can be generated based on the index of the interleaving in which SCIs are transmitted. Therefore, UEs uninterested in ongoing communication on an interleaving cannot identify sequences in transmissions from any Tx UE within the interleaving, allowing the UE to skip monitoring sequences on uninteresting interleavings and decoding SCIs or PSCCHs in such transmissions. For example, sequences can be generated according to the above equation and transmitted via c init = Interleaved index initialization.

[0063] According to some embodiments of this disclosure, sequences are predefined in a standard and generated based on the time slots and / or symbols in which the sequences are transmitted. For example, a sequence can be generated according to the above equation and initialized as follows:

[0064]

[0065] in It represents the number of symbols in the time slot, where l is the symbol number (also the symbol index) within the time slot. It is the slot number (also the slot index) within the frame, and N ID Given based on one or more of the following: cell ID, higher-level configured ID, TxUE ID, group ID for multicast communication, or interleaved index assigned for transmission sequence.

[0066] It should be understood that the above equations used to generate the sequences are provided for illustrative purposes only. Depending on the specific application of the sequence, those skilled in the art may design different equations or methods to generate the sequence based on one or more of the following: cell ID, higher-layer configured ID, Tx UE ID, group ID for multicast communication, or interleaved index assigned for transmitting the sequence.

[0067] Refer again Figure 3After generating the sequence, in step 304, the Tx UE may transmit the sequence at the start of a sidelink burst on the carrier. As described above, the Tx UE needs to perform a successful LBT procedure before transmitting the sidelink burst. The sequence may be generated before executing the LBT procedure. The start time of the sidelink burst may be unpredictable because the success time of the LBT procedure is unpredictable. To address this issue, a set of candidate start positions in the time slot used to start the sidelink burst (i.e., for transmitting the sequence) may be configured via RRC signaling or predefined in the standard. For example, a set of candidate positions may include symbols 0, 3, 6, and 9 in the time slot. Considering this, a set of candidate positions may include other possible symbol indices. When the LBT procedure begins, the Tx UE may initiate COT to transmit the sidelink burst, which may start from the nearest candidate position in the set of candidate positions. The sidelink burst is transmitted continuously in the time domain without any gaps.

[0068] In embodiments of this disclosure, the sequence is transmitted only at the start of a sidelink burst. Figure 4 This illustrates an example where the sequence is transmitted only at the start of a sidelink burst. In this example, the COT for the Tx UE to initiate a sidelink burst can span from time slot n to time slot n+3, and the sequence is transmitted only at the start of the sidelink burst in the first time slot (i.e., time slot n).

[0069] In another embodiment of this disclosure, in addition to transmitting the sequence at the start of the sidelink burst in the first time slot, the Tx UE may further transmit the sequence at the start of each of the other time slots of the sidelink burst (i.e., at symbol 0). Figure 5 This illustrates an example of transmitting a sequence in each time slot of a sidelink burst. In this example, the COT for the Tx UE to initiate the sidelink burst can span from time slot n to time slot n+3, and the sequence is transmitted at the start of the sidelink burst in the first time slot (i.e., time slot n) and at the start of each subsequent time slot (i.e., time slot n+1, time slot n+2, and time slot n+3). In this way, the Rx UE has a greater chance of detecting the sequence, especially when the Rx UE misses previous sequence transmissions due to half-duplex constraints.

[0070] As described above, a sequence is generated to occupy all subcarriers on the carrier. However, the sidelink burst is transmitted only within the bandwidth of the sidelink bandwidth portion (BWP) of the carrier and on the subcarriers (e.g., interleaved) within the sidelink BWP assigned to the sidelink burst; that is, the Tx UE is occupying the subcarrier to transmit the PSCCH and associated PSSCH. Therefore, only a portion of the sequence is transmitted at the intersection of the assigned interleaved portion and the sidelink BWP. In another embodiment, the Tx UE may transmit the sequence on all subcarriers within the bandwidth of the sidelink BWP. Again, only a portion of the sequence within the sidelink BWP is transmitted, not the entire generated sequence.

[0071] Figure 6 This document describes an exemplary flowchart of a method 600 for detecting sidelink transmission bursts on unlicensed spectrum according to some embodiments of the present disclosure. Method 600 can be performed by an Rx UE or other means with similar functionality.

[0072] like Figure 6 As shown, in step 602, the Rx UE can detect a sequence on the carrier at a first candidate position from a set of candidate positions in a time slot. The set of candidate positions can be configured via RRC signaling or predefined in the standard for the Rx UE to monitor sequences. For example, the set of candidate positions may include symbols 0, 3, 6, and 9 in the time slot. Considering this, the set of candidate positions may include other possible symbol indices.

[0073] The sequence can span a predetermined number of consecutive symbols in the time domain. In some embodiments of this disclosure, the predetermined number can be configured via RRC signaling or predefined in the standard based on the carrier's SCS value and AGC readjustment time.

[0074] In different applications, sequences can represent different indications for Rx UEs. For example, depending on the specific application of the sequence, the sequence can be based on one or more of the following: cell ID, higher-layer configured ID, Tx UE ID, group ID for multicast communication, or interleaved index assigned to the transmission sequence.

[0075] According to some embodiments of this disclosure, the sequence can be predefined in the standard as a common sequence for radio access technologies. For example, the Rx UE may determine whether the ongoing transmission uses 3GPP radio technology or WiFi depending on whether the sequence is detected during transmission.

[0076] According to some embodiments of this disclosure, the sequence can be predefined in a standard as a common sequence for sidelink transmissions between multiple cells. For example, the Rx UE may determine whether the ongoing transmission is a sidelink transmission from a Tx UE in one of the multiple cells depends on whether the sequence is detected during transmission.

[0077] According to some embodiments of this disclosure, the sequence can be predefined in the standard as a sidelink cell-specific sequence. For example, the Rx UE may determine whether the ongoing transmission is a sidelink transmission from a Tx UE in the same cell as the Rx UE depending on whether the sequence is detected during transmission.

[0078] According to some embodiments of this disclosure, the sequence can be predefined in the standard as a sidelink Tx UE-specific sequence. For example, the Rx UE may determine whether the ongoing transmission is a sidelink transmission from a Tx UE of interest to the Rx UE based on whether the sequence is detected during transmission.

[0079] According to some embodiments of this disclosure, the sequence is predefined in the standard as a sidelink group-specific sequence. For example, the Rx UE may determine whether an ongoing transmission is a sidelink multicast communication of interest to the Rx UE based on whether a sequence is detected during transmission.

[0080] According to some embodiments of this disclosure, the sequence is predefined in the standard as a sidelink interleaving-specific sequence. For example, the Rx UE may determine whether the ongoing transmission is being transmitted on an interleaving of interest to the Rx UE based on whether a sequence is detected during transmission.

[0081] As mentioned above Figure 3 The sequence can be predefined relative to subcarrier 0 of resource block 0 of the carrier and mapped in the frequency domain across all subcarriers of the carrier, but only a portion of the predefined sequence is transmitted in the assigned sidelink BWP. Therefore, the RxUE can detect only a portion of the predefined sequence within the sidelink BWP, rather than the entire generated sequence. In some embodiments of this disclosure, the sequence is detected only on subcarriers within the sidelink BWP assigned for sidelink transmission. In some embodiments of this disclosure, the sequence is detected on all subcarriers within the sidelink BWP.

[0082] Refer again Figure 6 If no sequence is detected at the first candidate position (i.e., the "No" branch of step 604), method 600 may return to step 602, and the Rx UE may detect the sequence at the second candidate position in a set of candidate positions within the time slot. The second candidate position may be after the first candidate position in a set of candidate positions. If no sequence is still detected at the second candidate position, the Rx UE may detect the sequence at the third candidate position in a set of candidate positions within the time slot, and so on, until the sequence is detected at a candidate position within the time slot. If the Rx UE fails to detect the sequence at any candidate position within the time slot, the Rx UE may skip the detection of SCI or PSCCH within the time slot and detect the sequence at each candidate position in the next time slot in the same manner.

[0083] When a sequence is detected at a candidate location in a time slot (i.e., the "Yes" branch of step 604), method 600 may continue to step 606, and the Rx UE may receive a sidelink transmission from the candidate location. For example, when a sequence is detected at a first candidate location, the Rx UE may receive a sidelink transmission on a carrier from the first candidate location; when a sequence is detected at a second candidate location, the Rx UE may receive a sidelink transmission on a carrier from the second candidate location. The Rx UE then detects the PSCCH and associated PSSCH in the sidelink transmission. According to some embodiments of this disclosure, when a sequence is detected by the Rx UE in a time slot, the Rx UE may skip the detection of other candidate locations in the same time slot. According to some embodiments of this disclosure, when a sequence is detected by the Rx UE in a time slot of a sidelink burst and the Rx UE knows the duration of the sidelink burst or the end location of the sidelink burst, the Rx UE may skip the detection of other candidate locations in the same sidelink burst.

[0084] Figure 7 This illustration depicts exemplary block diagrams of a device 700 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the device 700 may be capable of at least performing... Figure 3 The method described herein refers to the Tx UE or other devices with similar functionality.

[0085] like Figure 7 As shown, device 700 may include at least one receiving circuitry system 702, at least one transmitting circuitry system 704, at least one non-transitory computer-readable medium 706, and at least one processor 708 coupled to the at least one receiving circuitry system 702, the at least one transmitting circuitry system 704, and the at least one non-transitory computer-readable medium 706. Although in Figure 7 In the example shown, they are coupled to each other via at least one processor 708, but in various arrangements, at least one receiving circuitry system 702, at least one transmitting circuitry system 704, at least one non-transitory computer-readable medium 706, and at least one processor 708 may be coupled to each other. For example, at least one receiving circuitry system 702, at least one transmitting circuitry system 704, at least one non-transitory computer-readable medium 706, and at least one processor 708 may be coupled to each other via one or more local buses (not shown for simplicity).

[0086] Despite Figure 7In this disclosure, elements such as receiving circuitry system 702, transmitting circuitry system 704, non-transitory computer-readable medium 706, and processor 708 are described in the singular, but the plural form is contemplated unless explicitly stated to be limited to the singular. In some embodiments of this disclosure, at least one receiving circuitry system 702 and at least one transmitting circuitry system 704 are combined into a single device, such as a transceiver. In some embodiments of this disclosure, device 700 may further include input devices, memory, and / or other components.

[0087] In some embodiments of this disclosure, at least one non-transitory computer-readable medium 706 may store computer-executable instructions thereon, which may be programmed to cause at least one processor 708 to implement the steps of the method using at least one receiving circuit system 702 and at least one transmitting circuit system 704, for example as Figure 3 As described in the view. For example, when executed, the instructions may cause at least one processor 708 to produce a sequence of a predetermined number of consecutive symbols spanning the time domain. The instructions may further cause at least one processor 708 to transmit the sequence at the start of a sidelink burst on a carrier, starting from a first candidate position in a set of candidate positions in a first time slot, using at least one transmission circuit system 704, wherein the sidelink burst is transmitted continuously in the time domain without any gaps.

[0088] Figure 8 Exemplary block diagrams of a device 800 according to some embodiments of the present disclosure are provided. In some embodiments of the present disclosure, device 800 may be capable of at least performing Figure 6 The method described herein refers to the Rx UE or other devices with similar functionality.

[0089] like Figure 8 As shown, device 800 may include at least one receiving circuitry system 802, at least one transmitting circuitry system 804, at least one non-transitory computer-readable medium 806, and at least one processor 808 coupled to the at least one receiving circuitry system 802, the at least one transmitting circuitry system 804, and the at least one non-transitory computer-readable medium 806. Although in Figure 8 In the examples shown, they are coupled to each other via at least one processor 808, but in various arrangements, at least one receiving circuitry system 802, at least one transmitting circuitry system 804, at least one non-transitory computer-readable medium 806, and at least one processor 808 may be coupled to each other. For example, at least one receiving circuitry system 802, at least one transmitting circuitry system 804, at least one non-transitory computer-readable medium 806, and at least one processor 808 may be coupled to each other via one or more local buses (not shown for simplicity).

[0090] Despite Figure 8In this disclosure, elements such as receiving circuitry system 802, transmitting circuitry system 804, non-transitory computer-readable medium 806, and processor 808 are described in the singular, but the plural form is contemplated unless explicitly stated to be limited to the singular. In some embodiments of this disclosure, at least one receiving circuitry system 802 and at least one transmitting circuitry system 804 are combined into a single device, such as a transceiver. In some embodiments of this disclosure, device 800 may further include memory and / or other components.

[0091] In some embodiments of this disclosure, at least one non-transitory computer-readable medium 806 may store computer-executable instructions that are programmed to cause at least one processor 808 to perform the steps of the methods described herein using at least one receiving circuitry system 802 and at least one transmitting circuitry system 804. For example, when executed, the instructions may cause at least one processor 808 to detect a sequence at a first candidate position in a set of candidate positions in a time slot on a carrier, wherein the sequence spans a predetermined number of consecutive symbols in the time domain. The instructions may further cause at least one processor 808 to receive a sidelink transmission from the first candidate position using at least one receiving circuitry system 802 in response to detecting the sequence at the first candidate position in the time slot.

[0092] Those skilled in the art will understand that aspects of the embodiments may be embodied as systems, devices, methods, or program products. Therefore, embodiments may take the form of complete hardware embodiments, complete software embodiments (including firmware, resident software, microcode, etc.), or embodiments combining software and hardware aspects.

[0093] For example, the disclosed embodiments may be implemented as hardware circuitry (including custom very large-scale integration (“VLSI”) circuitry or gate arrays), off-the-shelf semiconductors (e.g., logic chips, transistors, or other discrete components). The disclosed embodiments may also be implemented in programmable hardware devices, such as field-programmable gate arrays, programmable array logic, programmable logic devices, or the like. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code, which may be organized, for example, as objects, programs, or functions.

[0094] Furthermore, embodiments may take the form of a program product embodied in one or more computer-readable storage devices storing machine-readable code, computer-readable code, or program code. The storage device may be tangible, non-transitory, or non-transferable. The storage device may not embody signals. In certain embodiments, the storage device uses only signals to access code.

[0095] Any combination of one or more computer-readable media may be used. The computer-readable media may be a computer-readable storage medium. The computer-readable storage medium may be a storage device for storing code. The storage device may be, for example (but not limited to), an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, device, or apparatus, or any suitable combination of the foregoing.

[0096] A non-exhaustive list of further specific examples of storage devices may include the following: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In the context of this invention, a computer-readable storage medium may be any tangible medium that may contain or store programs for use by or in conjunction with an instruction execution system, apparatus, or device.

[0097] Furthermore, the features, structures, or characteristics described in the embodiments can be combined in any suitable manner. While this disclosure has been described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that many alternatives, modifications, and variations will be readily apparent. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Moreover, not all elements of each figure are essential to the operation of the disclosed embodiments. For example, those of ordinary skill in the art will be able to make and use the teachings of this disclosure by simply employing the elements of the independent claims. Therefore, the embodiments of this disclosure set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of this disclosure.

[0098] Throughout this specification, references to “an embodiment,” “embodiment,” or similar language mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Therefore, unless expressly specified otherwise, the phrases “in one embodiment,” “in an embodiment,” and similar language appearing throughout this specification may (but not necessarily) refer to the same embodiment, but rather to “one or more, but not all, embodiments.” In this document, the term “includes / including” or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but may also include other elements not expressly listed or inherent to the process, method, article, or apparatus. Elements beginning with “a / an” or similar do not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element, without further constraints. Furthermore, the term “another” is defined as at least one second or more. As used herein, the terms “having” and similar are defined as “comprising.”

Claims

1. A method for wireless communication performed by a user equipment (UE), comprising: generating a sequence; and transmitting the sequence at a beginning of a sidelink burst on a carrier starting from a first candidate position in a set of candidate positions in a first slot, wherein the sequence spans a predetermined number of consecutive symbols in a time domain and the sidelink burst is transmitted continuously without any gap in the time domain, a length of the sequence is equal to a total number of subcarriers of the carrier multiplied by the predetermined number, and the sequence is cyclically mapped on each of the predetermined number of consecutive symbols in a frequency first manner or repeatedly mapped on each of the predetermined number of consecutive symbols.

2. The method of claim 1, wherein the sequence is predefined with respect to a subcarrier 0 of a resource block 0 of the carrier and mapped on all subcarriers of the carrier in a frequency domain.

3. The method of claim 1, wherein the sidelink burst is transmitted in a sidelink bandwidth part (BWP) of the carrier.

4. A user equipment (UE), comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: generate a sequence; and transmit the sequence at a beginning of a sidelink burst on a carrier starting from a first candidate position in a set of candidate positions in a first slot, wherein the sequence spans a predetermined number of consecutive symbols in a time domain and the sidelink burst is transmitted continuously without any gap in the time domain, a length of the sequence is equal to a total number of subcarriers of the carrier multiplied by the predetermined number, and the sequence is cyclically mapped on each of the predetermined number of consecutive symbols in a frequency first manner or repeatedly mapped on each of the predetermined number of consecutive symbols.

5. The UE of claim 4, wherein the sequence is predefined with respect to a subcarrier 0 of a resource block 0 of the carrier and mapped on all subcarriers of the carrier in a frequency domain.

6. The UE of claim 4, wherein the sidelink burst is transmitted in a sidelink bandwidth part (BWP) of the carrier.

7. The UE of claim 4, wherein the set of candidate positions is configured via radio resource control (RRC) signaling or predefined in a standard.

8. The UE of claim 4, wherein the predetermined number is configured via radio resource control (RRC) signaling or predefined in a standard or determined based on a subcarrier spacing value and an automatic gain control retuning time.

9. The UE of claim 4, wherein the sequence is transmitted only at the beginning of the sidelink burst.

10. The UE of claim 4, wherein the at least one processor is configured to cause the UE to transmit the sequence at a beginning of each slot of the sidelink burst other than the first slot.

11. The UE of claim 4, wherein the sequence indicates that a radio access technology is used.

12. The UE of claim 4, wherein the sequence is a common sequence for sidelink transmissions between multiple cells.

13. The UE of claim 4, wherein the sequence is generated based on one or more of a cell identification (ID), a higher layer configured ID, an ID of the UE, a group ID for groupcast communications, or a staggering index assigned for transmitting the sequence.

14. A user equipment (UE), comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: detect a sequence at a first candidate position of a set of candidate positions in a slot on a carrier, wherein the sequence spans a predetermined number of consecutive symbols in a time domain; and receive a sidelink transmission from the first candidate position in the slot in response to detecting the sequence at the first candidate position, wherein the sequence spans a predetermined number of consecutive symbols in a time domain, a length of the sequence is equal to a total number of subcarriers of the carrier multiplied by the predetermined number, and the sequence is cyclically mapped on each of the predetermined number of consecutive symbols in a frequency-first manner or repeatedly mapped on each of the predetermined number of consecutive symbols.

15. The UE of claim 14, wherein the at least one processor is further configured to cause the UE to detect the sequence at a second candidate position of the set of candidate positions in the slot in response to not detecting the sequence at the first candidate position, wherein the second candidate position is after the first candidate position of the set of candidate positions.

16. The UE of claim 14, wherein the at least one processor is further configured to cause the UE to skip detection of a physical sidelink control channel in the slot in response to not detecting the sequence at any candidate position of the set of candidate positions in the slot.

17. The UE of claim 14, wherein the sequence is predefined with respect to subcarrier 0 of resource block 0 of the carrier and mapped on all subcarriers of the carrier in a frequency domain.

18. The UE of claim 14, wherein the set of candidate positions is configured via radio resource control (RRC) signaling or predefined in a standard.

19. The UE of claim 14, wherein the predetermined number is configured via radio resource control (RRC) signaling or predefined in a standard.

20. A method performed by a user equipment (UE) for wireless communication, comprising: detecting a sequence at a first candidate position of a set of candidate positions in a slot on a carrier, wherein the sequence spans a predetermined number of consecutive symbols in a time domain; and receiving a sidelink transmission from the first candidate position in the slot in response to detecting the sequence at the first candidate position, wherein a length of the sequence is equal to a total number of subcarriers of the carrier multiplied by the predetermined number, and the sequence is cyclically mapped on each of the predetermined number of consecutive symbols in a frequency-first manner or repeatedly mapped on each of the predetermined number of consecutive symbols.

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