WO2024065730A1

WO2024065730A1 - Transmission methods of sl-u

Info

Publication number: WO2024065730A1
Application number: PCT/CN2022/123392
Authority: WO
Inventors: Junqiang CHENG; Tao Chen
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04
Also published as: CN117812716A

Abstract

This disclosure describes transmission methods of SL-U. One and/or multiple starting symbols within a slot can be (pre-)configured for transmission. The PSCCH can indicate the configurations of the corresponding PSSCH(s) in one and/or multiple slot(s).

Description

TRANSMISSION METHODS OF SL-U

FIELD

The invention discussed below relates generally to wireless communication systems, and more particularly, to transmission methods of SL-U.

BACKGROUND

For sidelink (SL) transmitted on unlicensed spectrum (SL-U) , in time domain, considering the LBT channel access operation, LBT may succeed in the middle of the slot. For legacy NR-U, the gNB/UE can access the channel at symbol-level after the LBT channel access is finished, which can improve the channel access efficiency when it competes with other RAT (s) , e.g., WiFi. For legacy SL, the minimum unit for scheduling is a slot, which means even if the LBT is finished within a slot, the transmission can only be started at the next slot boundary. The gap between the LBT end position and the transmission start position increase the risk of COT loosing. That is the motivation of introducing additional starting symbol (s) within a slot for SL-U to improve its channel access opportunity. Correspondingly, the essential enhanced mechanisms (e.g., slot structure, PSCCH/PSSCH channel) have to be re-designed to better support SL-U.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

Various aspects of the present disclosure relate to the transmission methods of SL-U. Specifically, one and/or multiple starting symbols (s) within a slot is supported for SL-U to start a transmission. It can be (pre-) configured that PSCCH can be transmitted on each starting symbol within a slot; or only PSSCH (e.g., for AGC/combining purpose) can be transmitted on the starting symbols other than the 1st starting symbol within a slot. Additionally, the (control) indicator (e.g., 1 ^st and/or 2 ^nd SCI) can be used to indicate the configuration/information (e.g., the starting position/offset, and/or symbol length, and/or AGC/repetition/combining configuration, and/or DMRS pattern) of the PSSCH (s) in partial and/or one and/or multiple slot (s) . Based on the UE implementation and/or UE capability, the UE can be (pre-) configured whether/how many data should be buffered down in the past (partial) slot.

In another aspect of the disclosure, for frequency framework, one sub-channel can be used as the frequency domain resource allocation granularity. PSCCH is always transmitted within one fixed sub-channel. For the transmission of PSCCH in the case where Tx UE uses multiple RB sets, it depends on the (pre-) configuration that PSCCH can be transmitted within 1 fixed sub-channel (e.g., the 1 ^st/lowest sub-channel) of one RB set (e.g., the 1 ^st/lowest RB set) of the occupied multiple RB sets, and/or PSCCH can be transmitted within 1 fixed sub-channel (e.g., the 1 ^st/lowest sub-channel) of each RB set of the occupied multiple RB sets. Additionally, for out-of-COT operation, the PSSCH should start from the sub-channel occupied by the corresponding PSCCH. For in-COT operation, the resource of PSSCH can be scheduled by the COT initiator and/or group head UE.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed figures set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary diagram of the present transmission methods of SL on unlicensed spectrum.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

This invention is motived by, but not limited to, a scenario where SL operated on unlicensed spectrum. In such scenario, several new features related to transmission methods of SL-U have to be addressed. For example, The design of slot structure/pattern, and PSCCH/PSSCH channel structure. To this end, the transmission methods of SL-U are presented in this disclosure.

In this disclosure, one and/or multiple starting symbol (s) within a slot is supported for SL-U to start a transmission. Additionally, for the case that SL-U UE can access the channel with multiple starting symbols within a slot, as an example shown in Figure 1, two options can be (pre-) configured. Option 1: PSCCH can be transmitted on the each starting symbols within a slot. Option 2: Only PSSCH (e.g., for AGC and/or combining purpose) can be transmitted on the starting symbols other than the 1st starting symbol within a slot. In both Option 1-1 and Option 1-2, CP extension operation can be implemented to achieve us-to-symbol boundary alignment, thus SL-U UE can start a transmission on the channel as soon as the LBT procedure is finished.

For the case that multiple starting symbols with only PSSCH transmission from starting symbols other than the 1 ^st starting symbol: multiple starting symbols within a slot to achieve an equivalent channel access ability for SL-U compared to the other RATs (e.g., WiFi and/or NR-U) . Besides, only PSSCH (repetition) transmission allowed on the starting symbols other than the 1st starting symbol within a slot to reduce UE complexity and power consumption due to the blind detection/decoding of PSCCH.

Additionally, the indicator (e.g., control indicator) can indicate the corresponding PSSCH (s) in partial and/or one and/or multiple slot (s) . For example, the PSCCH (in the 1st starting symbol of the full slot) can indicate the information and/or configuration of the PSSCH in both the past (partial) slot and the current and/or the following full slot (s) . The information and or configuration can include such as the starting position/offset of the symbol, and/or the starting symbols, and/or symbol length, and/or the configuration of AGC/repetition/combining, and/or the DMRS pattern. For example, the starting symbols can be indicated for AGC/combining purpose.

The indicator of the PSSCH (s) configuration can be carried in 1 ^st SCI and/or 2 ^nd SCI. For example, the configuration of the PSSCH (s) in partial and/or one and/or multiple slot (s) can be indicated with additional bit (s) (in the reserved bit) of 1 ^st SCI and/or 2 ^nd SCI separately. Alternatively, it can be indicated by both 1 ^st SCI and 2 ^nd SCI. For example, one additional bit in the 1 ^st SCI can be used to indicate whether the current control is used to indicate only the PSSCH in the current slot or the PSSCH (s) in both the current slot and the past (partial) slot. For the latter case, the indication of the other configurations of the PSSCH (s) is carried and can be found in the 2 ^nd SCI. A bitmap, and/or a table can be (pre-) configured and/or indicated to show the PSSCH (s) configurations.

In another aspect of the disclosure, depends on the UE implementation and/or UE capability (report) , the UE can be (pre-) configured whether and/or how many PSSCH should be buffered down in the past (partial) slot (for potential combining) . For example, three options may be (pre-) configured.

Option 1: Buffer down all the data/PSSCH in both past (partial) slot and current full slot to gain an optimal combining performance.

Option 2: Buffer down a part of the data/PSSCH in the past (partial) slot and all data/PSSCH in current full slot to achieve a trade-off between performance and buffer storage.

Option 3: Buffer down only the PSSCH in current full slot to achieve low buffer.

Therefore, in this disclosure, for the case that multiple starting symbols within a slot, CP extension operation is supported to achieve us-to-symbol boundary alignment. Additionally, only PSSCH transmission is supported from starting symbols other than the 1st starting symbol within a slot to achieve symbol-to-slot boundary alignment. Additionally, PSCCH can only be transmitted on the 1st starting symbol within a slot and can be used to jointly indicate the configuration of the corresponding PSSCH (s) in current full slot and/or past (partial) slot and/or the next (full) slot.

In another aspect of the disclosure, for the PSCCH/PSSCH channel structure design, one sub-channel can be used as the granularity of frequency domain. For interlace based transmission, one sub-channel equals K interlace (s) within one RB set for interlace RB-based transmission, where K is (pre-) configured. For contiguous based transmission, one sub-channel equals N continuous RB (s) within one RB set for contiguous RB-based transmission, where N is (pre-) configured.

Additionally, PSCCH should be transmitted within one fixed sub-channel. For example, for the case where Tx UE uses multiple RB sets, PSCCH can be transmitted within 1 fixed sub-channel (e.g., the 1 ^st/lowest sub-channel) of one RB set (e.g., the 1 ^st/lowest RB set) of the occupied multiple RB sets, and/or PSCCH can be transmitted within 1 fixed sub-channel (e.g., the 1 ^st/lowest sub-channel) of each RB set of the occupied bandwidth. Besides, PSCCH should locate in the sub-channel with the lowest index of the sub-channel (s) of the corresponding PSSCH.

Additionally, the resource allocated for PSSCH should start from the sub-channel of the corresponding PSCCH. For example, for out-of-COT operation and/or for the transmission immediately after and/or closest to the LBT end, the PSSCH should start from the 1 ^st/lowest sub-channel of the occupied (overall) bandwidth. For in-COT operation, the PSSCH can be scheduled (e.g., by COT initiator) to start from the 1 ^st/lowest sub-channel of the indicated/scheduled/allocated bandwidth.

In another aspect of the disclosure, for the transmission of S-SSB in SL-U, it can be (pre-) configured that the S-SSB can be transmitted without sensing the channel. Additionally, for the transmission of PSFCH, it can be (pre-) configured a Type 1 channel access procedure should be performed without shared channel occupancy and Type 2 channel access procedure should be performed in a shared channel occupancy. The CAPC value for PSFCH can be set as 1 and/or same as the corresponding PSSCH based on the (pre-) configuration.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “UE, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.

Claims

A transmission method for SL-U, wherein one and/or multiple transmission starting symbol (s) is/are (pre-) configured within a slot.
The method of claim 1, wherein the PSCCH is transmitted on each starting symbol within a slot.
The method of claim 1, wherein only PSSCH is transmitted on the starting symbols other than the 1st starting symbol within a slot.
The method of claim 1, wherein (control) indicator is used to indicate the configuration/information of the PSSCH (s) in partial and/or one and/or multiple slot (s) .
The method of claim 1, wherein UE is (pre-) configured whether/how many data should be buffered down in the past (partial) slot based on UE implementation and/or UE capability.
The method of claim 1, wherein one sub-channel is used as the frequency domain resource allocation granularity.
The method of claim 1, PSCCH is always transmitted within one fixed sub-channel within one RB set and/or each RB set of the occupied bandwidth.
The method of claim 1, wherein for out-of-COT operation, the PSSCH should start from the sub-channel occupied by the corresponding PSCCH in the overall occupied bandwidth.
The method of claim 1, wherein for in-COT operation, the PSSCH is scheduled by the COT initiator and/or group head UE to start from the sub-channel occupied by the corresponding PSCCH in the indicated/allocated/scheduled bandwidth.