Patent Description:
The following abbreviations and acronyms are herewith defined, at least some of which are referred to in the following description.

Third Generation Partnership Project ("3GPP"), Positive-Acknowledgment ("ACK"), Channel State Information ("CSI"), Control Channel ("CCH"), Device-to-Device ("D2D"), further enhancement Device-to-Device ("feD2D"), Downlink Control Information ("DCI"), Downlink ("DL"), Demodulation Reference Signal ("DMRS"), Evolved Node B ("eNB"), European Telecommunications Standards Institute ("ETSI"), Frequency Division Duplex ("FDD"), Frequency-Division Multiplexing ("FDM"), Frequency Division Multiple Access ("FDMA"), Long Term Evolution ("LTE"), LTE Advanced ("LTE-A"), Multiple Access ("MA"), Machine Type Communication ("MTC"), Narrowband ("NB"), Negative-Acknowledgment ("NACK") or ("NAK"), Orthogonal Frequency Division Multiplexing ("OFDM"), Physical Downlink Control Channel ("PDCCH"), Physical Downlink Shared Channel ("PDSCH"), Physical Sidelink Control Channel ("PSCCH"), Physical Sidelink Shared Channel ("PSSCH"), Physical Uplink Control Channel ("PUCCH"), Physical Uplink Shared Channel ("PUSCH"), Quality of Service ("QoS"), Radio Network Temporary ("RNTI"), Identity Radio Resource Control ("RRC"), Reference Signal Receiving Power ("RSRP"), Reference Signal Strength Indicator ("RSSI"), Receive ("RX"), Scheduling Assignment ("SA"), Scheduling Request ("SR"), Shared Channel ("SCH"), Sidelink Control Information ("SCI"), System Information Block ("SIB"), Sidelink ("SL"), Semi-Persistent Scheduling ("SPS"), Sounding Reference Signal ("SRS"), Transport Block ("TB"), Transport Block Size ("TBS"), Transmission Control Protocol ("TCP"), Time Division Duplex ("TDD"), Time-Division Multiplexing ("TDM"), Transmission Time Interval ("TTI"), Transmit ("TX"), Uplink Control Information ("UCI"), User Datagram Protocol ("UDP"), User Entity/Equipment (Mobile Terminal) ("UE"), Uplink ("UL"), Universal Mobile Telecommunications System ("UMTS"), Next Generation ("NR"), Radio Access Network ("RAN"), Vehicle-to-Vehicle ("V2V") and Vehicle-to-Everything ("V2X"). As used herein, SL communication is also known as D2D communication.

Both D2D and V2V communication are broadcast-based communication currently. However, broadcast-based communication does not meet the requirements for resource utilization efficiency, throughput, QoS, reliability, complexity and power consumption. Therefore, a new study on improvement of resource utilization efficiency has been developed, which proposes to support physical layer HARQ feedback procedure, feedback resource allocation and pre-emption of reserved resources on sidelink.

R1-<NUM> describes support of Sidelink Unicast, Groupcast and Broadcast Modes for NR V2X Communication. R1-<NUM> describes feedback information for sidelink adaptation. <CIT> describes user equipment, feedback control method and retransmission control method.

Both 3GPP Rel-<NUM>/Rel-<NUM> D2D communication and 3GPP Rel-<NUM> V2V communication are typical broadcast-based communications, wherein one of the main objectives is to enable as many receivers as possible to successfully decode the messages. Mechanisms such as blind (re)transmission without feedback are no longer suitable for unicast communication. Enhancements to SL communication should be studied to support physical layer HARQ feedback procedure, feedback resource allocation and pre-emption of reserved resources in order to meet the requirements for resource utilization efficiency, throughput, QoS, reliability, complexity and power consumption.

Enhancements to improve resource utilization efficiency require effective mechanisms to utilize the reserved resources, which will not be used however, in order to avoid wasting on the resources. There is thus a need to develop a new mechanism for pre-emption of the reserved but unused resources.

In unicast-based SL communication, it is beneficial to feedback for decoding result feedback corresponding to SL data transmission; thereby the mechanism for the transmission of the decoding result feedback should also be studied.

Methods and apparatus for resource pre-emption in SL communication are disclosed. One method of a Tx UE comprises reserving resources for one or more SL data transmissions and resources for decoding result feedbacks corresponding to the one or more SL data transmissions; and transmitting sidelink control information (SCI) to a second apparatus, which indicates the resources for the SL data transmissions, receiving at least one of the decoding result feedback and a pre-emption indicator; further comprising receiving the pre-emption indicator in the resources for the decoding result feedback, which indicates the second apparatus will pre-empt the reserved resources for the SL data transmission, in the case that the decoding result feedback is a positive feedback.

Given that these drawings depict only some embodiments and are not therefore to be considered to limit scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:.

As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or a program product. Accordingly, embodiments may take the form of an all-hardware embodiment, an all-software embodiment (including firmware, resident software, micro-code, etc.), or an embodiment combining software and hardware aspects.

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, and/or program code, collectively referred to hereafter as "code".

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

A non-exhaustive list of more specific examples of the storage device may include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, random-access memory ("RAM"), read-only memory ("ROM"), an erasable programmable read-only memory ("EPROM" or flash memory), a portable compact disc read-only memory ("CD-ROM"), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

Reference throughout this specification to "one embodiment", "an embodiment", or similar language, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The terms "including", "comprising", "having", and variations thereof mean "including but not limited to", unless expressly specified otherwise. The terms "a", "an", and "the" also refer to "one or more" unless expressly specified otherwise.

This code may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions - executed via the processor of the computer or other programmable data-processing apparatus - create a means for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagrams.

The code may also be stored in a storage device that can direct a computer, other programmable data-processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the schematic flowchart diagrams and/or schematic block diagrams.

The code may also be loaded onto a computer, other programmable data-processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other devices to produce a computer implemented process such that the code executed on the computer or other programmable apparatus provides processes for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagram.

For example, two blocks shown in succession may, in fact, be substantially executed in concurrence, or the blocks may sometimes be executed in reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, from the illustrated Figures.

Enhancements to SL should be studied to support physical layer HARQ feedback procedure, feedback resource allocation and pre-emption of reserved resources on sidelink in order to meet the requirements for resource utilization efficiency, throughput, QoS, reliability, complexity and power consumption. Disclosed herein are methods and apparatus that provide a mechanism of pre-emption of the reserved resources in SL communication. The Tx orRx UE may either be a relay UE or a remote UE depending on the context. From the perspectives of both Tx UE and Rx UE, it is crucial to reserve resources for feedbacks corresponding to the one or more SL data transmissions at the beginning of the communication between the Rx UE and Tx UE. Exemplary schemes for indication of SL data transmission, exemplary ways for learning the reserved resources for the feedback, exemplary ways for pre-empting the reserved resources and the exemplary ways for receiving the feedback are to be described in details below with respect to <FIG>.

<FIG> is a call flow illustrating data transmission between a Tx UE and a Rx UE in the case that the SCI indicates the resources for current SL data transmission and the resources for next SL data transmission according to a first embodiment. As shown in <FIG>, SL communication between Tx UE <NUM> and Rx UE <NUM> begins at step <NUM>, in which initial SCI is transmitted from the Tx UE <NUM> to the Rx UE <NUM>. Particularly, the SCI in step <NUM> indicates resources for initial transmission and retransmission of one transport block (TB), i.e. the first and second transmission of SL data. Multiple SL data transmissions may be for same transport block or different transport blocks. In one embodiment, the resources for SL data transmissions are included in sets of SL resources, for example-the number of which is set to be <NUM>, i.e., for current (the first) transmission and subsequent (the second) retransmission. Besides the resources for SL data transmissions, the sets of SL resources may include resources for decoding result feedback corresponding to the SL data transmissions and resources for SCI transmissions.

Simultaneously or sequentially, in step <NUM>, SL data is transmitted from the Tx UE <NUM> to the Rx UE <NUM> over the first reserved resources for SL data transmission.

In response to receiving both the SCI and the SL data, the Rx UE <NUM> attempts to decode the received data. In the case that the data is decoded unsuccessfully, the Rx UE <NUM> transmits a negative feedback of NACK to the Tx UE <NUM> on the resources for decoding result feedback, which may be indicated in the SCI from the Tx UE <NUM> or derived from at least one of the resources for SL data transmissions and the resources for SCI transmissions, in step <NUM>.

In response to receiving the NACK in step <NUM>, the Tx UE <NUM> transmits the second SCI over the reserved resources for the SCI transmission in step <NUM>, and SL data over the second reserved resource for SL data transmissions in step <NUM>. Further, the SCI in step <NUM> indicates resources for the second and the third transmissions of SL data, which is similar with the SCI in step <NUM>.

In <FIG>, the decoding result feedback corresponding to the SL data in step <NUM> is a positive feedback of ACK, shown as in step <NUM>. Although it is not shown in <FIG>, it should be understood that in the case where the decoding result feedback in step <NUM> is still a negative feedback of NACK, the Tx UE <NUM> will transmit the SL data again until a maximum number of transmission is reached.

In some embodiments, an exemplary format for SCI may include one or more fields as below: QoS level of SL data transmission, including at least one of a priority of SL data transmission, a latency requirement of SL data transmission, a reliability requirement of SL data transmission, frequency and/or time resource location of initial transmission and retransmission, time offset between initial transmission and retransmission of SL data, modulation and coding scheme (MCS), transmission format indicating whether rate-matching and TBs scaling are applied, retransmission index indicating whether the transmission of SL data corresponding to the SCI is retransmission or initial transmission, frequency and/or time resource location of reserved SL data transmission resource, time offset between current SL data transmission and reserved resource for the next SL data transmission, frequency and/or time resource location of feedback transmission, reservation indication of SL data transmission, HARQ process number, destination identifier (ID), source identifier (ID), session identifier (ID).

<FIG> is a schematic diagram illustrating resource allocation and reservation indication in the case that the SCI indicates the resources for current SL data transmission and the resources for next SL data transmission according to the first embodiment. As shown in <FIG>, the shaded blocks represent resources for SCIs, while the blank blocks represent resources for SL data. The resources for decoding result feedback corresponding to the SL data are not explicitly shown in <FIG>, however, they can be associated with the resources for SCI. For example, the resources for decoding result feedback may have fixed time offset to that for the SCI indicating the corresponding SL data transmission, the time offset may be depended on UE process time or pre-configured by gNB or pre-defined (e.g., <NUM>), and have the same subcarriers with SCI in frequency domain. Alternatively, the resources for decoding result feedback may be in a new independent channel other than the legacy PSSCH or PSCCH.

<FIG> is shown in combination with <FIG>, the resource for the SCI in step <NUM> is represented by the shaded block <NUM>, and the resource for the SCI in step <NUM> is represented by the shaded block <NUM>. As shown in <FIG>, the SCI (in step <NUM> of <FIG>) carried in the shaded block <NUM> indicates the resources for initial (first) transmission and retransmission (second) of SL data, which are represented by the blank block <NUM> and <NUM>, respectively. Similarly, the SCI (in step <NUM> of <FIG>) carried in the shaded block <NUM> indicates the resources for current (second) and next (third) transmission of SL data, which are represented by the blank block <NUM> and <NUM>, respectively. Namely, the resource for the SL data transmission in step <NUM> is represented by the blank block <NUM>, the resource for the SL data transmission in step 107is represented by the blank block <NUM>. As shown in <FIG> and <FIG>, each SCI indicates the resources for current SL data transmission and the resources for next SL data transmission.

<FIG> is a call flow illustrating data transmission between a Tx UE and a Rx UE in the case that the SCI indicates the resources for the one or more SL data transmissions according to a second embodiment. As shown in <FIG>, SL communication between a Tx UE <NUM> and a Rx UE <NUM> begins at step <NUM>, in which SCI is transmitted from the Tx UE <NUM> to the Rx UE <NUM>. Particularly, the SCI indicates resource for one or more transmission of SL data. The difference between the SCI in the first and second embodiment is in that, the SCI in the second embodiment indicates all of the reserved resources for SL data transmissions. In this case, the sequential SCIs shown in <FIG> are not needed.

Simultaneously or sequentially, SL data <NUM> is transmitted from the Tx UE <NUM> to the Rx UE <NUM> over the first reserved resource for SL data transmission.

In response to receiving both the SCI <NUM> and the SL data <NUM>, the Rx UE <NUM> attempts to decode the received data. In the case that the data is decoded unsuccessfully, the Rx UE <NUM> transmits a negative feedback of NACK to the Tx UE <NUM> on the resources for decoding result feedback, which may be indicated in the SCI from the Tx UE <NUM> or derived from at least one of the resources for SL data transmissions and the resources for SCI transmissions, in step <NUM>.

In response to receiving the NACK in step <NUM>, the Tx UE <NUM> transmits SL data over the second reserved resource for SL data transmissions in step <NUM>. As mentioned above, the resources for SL data transmission in step <NUM> are already indicated by the SCI in step <NUM>.

In some embodiments, an exemplary format for SCI includes one or more fields as below: priority of SL data transmission, frequency resource location of initial transmission and retransmission, time offset between successive SL data transmission, a maximum number of the SL data transmissions, modulation and coding scheme (MCS), transmission format indicating whether rate-matching and TBs scaling are applied, retransmission index indicating whether the transmission of SL data corresponding to the SCI is retransmission or initial transmission.

<FIG> is a schematic diagram illustrating resource allocation and reservation indication in the case that the SCI indicates the resources for the one or more SL data transmissions according to the second embodiment. As shown in <FIG>, the shaded blocks represent resources for SCI, while the blank blocks represent resources for SL data. The resources for decoding result feedback corresponding to the SL data are not explicitly shown in <FIG>, however, they can be associated with the resources for SCI and SL data. For example, the resources for decoding result feedback may have fixed time offset to that for the SL data in time domain, the time offset may be depended on UE process time or pre-configured by gNB or pre-defined (e.g., <NUM>), and have the same subcarriers with SCI in frequency domain. Alternatively, the resources for decoding result feedback may be in a new independent channel other than the legacy PSSCH or PSCCH. <FIG> is shown in combination with the <FIG>, the resource for the SCI <NUM> is represented by the shaded block <NUM>. As shown in <FIG>, the SCI (in step <NUM> of <FIG>) carried in the shaded block <NUM> indicates the resources for one or more transmission of SL data, which are represented by the blank block <NUM>, <NUM> and <NUM>, assuming the number of one or more SL data transmissions is set to be three. Namely, the resource for the SL data transmission in step <NUM> is represented by the blank block <NUM>, the resource for the SL data transmission in step <NUM> is represented by the blank block <NUM>. As shown in <FIG> and <FIG>, the SCI indicates the resources for the one or more SL data transmissions.

<FIG> is a call flow illustrating data transmission between a Tx UE and a Rx UE in the case that Rx UE pre-empts the resource reserved by the Tx UE under the context of <FIG> according to a third embodiment.

As shown in <FIG>, SL communication between Tx UE <NUM> and Rx UE <NUM> begins at step <NUM>, in which initial SCI is transmitted from the Tx UE <NUM> to the Rx UE <NUM>. The steps <NUM> and <NUM> are similar with steps <NUM> and <NUM>, therefore the description thereof are omitted for the purpose of brevity.

In response to receiving both the SCI and the SL data, the Rx UE <NUM> attempts to decode the received data. In the case that the data is decoded successfully, the Rx UE <NUM> transmits a positive feedback of ACK and a pre-emption indication to the Tx UE <NUM> in step <NUM>, which indicates the Rx UE <NUM> is going to pre-empt the reserved resources by the Tx UE <NUM> considering the SL data from Tx UE <NUM> has been successfully received and decoded. In a preferred embodiment, the pre-emption indication is transmitted along with the positive feedback, however, the present disclosure is not limited to so.

Further, the pre-emption indicator may be transmitted in the reserved resources for the decoding result feedback. In the case that the decoding result feedback is included in the SCI from the Rx UE <NUM> as a field, a field for the pre-emption indicator is also included in the same SCI.

In another embodiment, a field for a flag, which indicates that a field for the decoding result feedback indicates the pre-emption indicator, is included in SCI from the Rx UE <NUM>. For example, if the flag is set to be <NUM>, the field for the decoding result feedback is re-used for the pre-emption indicator, which implies that the decoding result feedback is a positive feedback and the Rx UE is going to pre-empt the reserved resource by the Tx UE. On the contrary, if the flag is set to be <NUM>, the field for the decoding result feedback still indicates the decoding result feedback corresponding to the SL data transmission for the Tx UE <NUM>.

In yet another embodiment, the pre-emption indicator is piggybacked in the resources for the decoding result feedback. In the case that the decoding result feedback is included in the SCI from the Rx UE <NUM>, thereby carried in PSCCH, the pre-emption indicator is piggybacked in PSCCH, but not included in the SCI as a field.

Optionally, the Rx UE <NUM> transmits another SCI over the reserved resources for the SCI transmission by the Tx UE <NUM> in step <NUM>, and SL data over the reserved resource for SL data transmissions by the Tx UE <NUM> in step <NUM>. Further, besides the resources for SL data transmission from the Rx UE - which is same with the reserved resources for SL data transmission by the Tx UE and indicated by the SCI in step <NUM>, the SCI <NUM> may indicate a configuration for the SL data transmission from the Rx UE <NUM>, including but not limited to: QoS level of SL data transmission, including at least one of a priority of SL data transmission, a latency requirement of SL data transmission, a reliability requirement of SL data transmission, frequency and/or time resource location of initial transmission and retransmission, modulation and coding scheme (MCS), transmission format indicating whether rate-matching and TBs scaling are applied, frequency and/or time resource location of feedback transmission, HARQ process number, destination identifier (ID), source identifier (ID), session identifier (ID).

In response to receiving the SCI and SL data from the Rx UE <NUM>, in step <NUM>, the Tx UE <NUM> transmits a positive/negative feedback of ACK/NACK, indicating a successful/unsuccessful decoding on the SL data from the Rx UE <NUM>.

<FIG> is a call flow illustrating data transmission between Tx UE and Rx UE in the case that Rx UE pre-empts the resource reserved by Tx UE under the context of <FIG> according to a fourth embodiment.

As shown in <FIG>, SL communication between a Tx UE <NUM> and a Rx UE <NUM> begins at step <NUM>, in which SCI <NUM> is transmitted from the Tx UE <NUM> to the Rx UE <NUM>. The steps <NUM> and <NUM> are similar with steps <NUM> and <NUM>, therefore the description thereof are omitted for the purpose of brevity.

In response to receiving both the SCI and the SL data, the Rx UE <NUM> attempts to decode the received data. In the case that the data is decoded successfully, the Rx UE transmits a positive feedback of ACK, a pre-emption indication and optionally, and/or a configuration for SL data transmission from the Rx UE <NUM>, in step <NUM>. The transmission of the pre-emption indicator indicates the Rx UE <NUM> is going to pre-empt the reserved resources by the Tx UE <NUM>, considering the SL data from Tx UE <NUM> has been successfully received and decoded. In a preferred embodiment, the pre-emption indication is transmitted along with the positive feedback, however, the present disclosure is not limited to so. As mentioned above, the configuration for the SL data transmission from the Rx UE <NUM> includes but not limited to: QoS level of SL data transmission, including at least one of a priority of SL data transmission, a latency requirement of SL data transmission, a reliability requirement of SL data transmission, frequency and/or time resource location of initial transmission and retransmission, modulation and coding scheme (MCS), transmission format indicating whether rate-matching and TBs scaling are applied, frequency and/or time resource location of feedback transmission, HARQ process number, destination identifier (ID), source identifier (ID), session identifier (ID).

Similar with transmission of the pre-emption indication in the third embodiment, the pre-emption indicator may be transmitted in the reserved resources for the decoding result feedback. In the case that the decoding result feedback is included in the SCI from the Rx UE <NUM> as a field, a field for the pre-emption indicator is also included in the same SCI.

Then in step <NUM>, the Rx UE <NUM> transmits SL data over the reserved resources for the SL data transmission by the Tx UE <NUM>, which is indicated by the SCI in step <NUM>.

In response to receiving the SL data from the Rx UE <NUM>, in step <NUM>, the Tx UE <NUM> transmits a positive/negative feedback of ACK/NACK, indicating a successful/ unsuccessful decoding on the SL data from the Rx UE <NUM>.

<FIG> is a call flow illustrating a mechanism of a Tx UE receiving a decoding result feedback from a Rx UE according to a fifth embodiment. As shown in <FIG>, a Tx UE <NUM>, a Rx UE <NUM> and a third UE <NUM> are involved. The SL communication between Tx UE <NUM> and Rx UE <NUM> begins at step <NUM>, in which SCI is transmitted from the Tx UE <NUM> to the Rx UE <NUM>. The SCI in step <NUM> indicates the resources for current SL data transmission and the resources for next SL data transmission as mentioned in the first embodiment, or resources for one or more SL data transmission in the second embodiment. Simultaneously or sequentially, SL data is transmitted from the Tx UE <NUM> to the Rx UE <NUM> over the reserved resource for SL data in step <NUM>.

In step <NUM>, the Rx UE <NUM> includes a field for the decoding result feedback corresponding to the SL data transmission in step <NUM>, in SCI directed to the third UE <NUM>. Fields other than the field for the decoding result feedback in the SCI from Tx UE <NUM> indicates a scheduling assignment (SA) for SL data transmission from Rx UE <NUM> to a third UE <NUM>. In response to receiving the SCI from the Rx UE <NUM>, the Tx UE <NUM> detects that the SCI is not directed to itself according to the destination identifier (ID) of the received SCI, and therefore focuses on the field for decoding result feedback to retrieve the result for the SL data transmission in step <NUM>. In another aspect, in response to receiving the SCI from the Rx UE <NUM>, the third UE <NUM> detects that the SCI is directed to itself according to the destination ID thereof, and therefore retrieve the SA for the SL data transmission from the Rx UE <NUM>. Although the third UE <NUM> is shown differently from the Tx UE <NUM>, it should be understood by the one skilled in the relevant art that the third UE <NUM> can be a same entity with the Tx UE, with the SL data from the Rx UE <NUM> being independent with that from Tx UE <NUM>.

In step <NUM>, the Rx UE transmits SL data to the third UE according to the SA mentioned above. In step <NUM>, in response to successfully/unsuccessfully decoding the SL data, the third UE transmits a positive/negative feedback of ACK/NACK.

<FIG> is a call flow illustrating another mechanism of a Tx UE receiving a decoding result feedback from a Rx UE according to the sixth embodiment. As shown in <FIG>, a Tx UE <NUM>, a Rx UE <NUM> and a third UE <NUM> are involved. The steps <NUM>, <NUM>, <NUM> and <NUM> are similar with the steps <NUM>, <NUM>, <NUM> and <NUM>, respectively. Therefore, the descriptions thereof are omitted for the purpose of brevity.

In step <NUM>, the Rx UE <NUM> enables the decoding result feedback corresponding to the SL data transmission in step <NUM> to be piggybacked in the resources for SCI transmitted from the Rx UE <NUM> to the third UE. In response to receiving the SCI from the Rx UE <NUM>, the Tx UE <NUM> detects that the SCI is not directed to itself according to the destination identifier (ID) of the received SCI, and therefore focuses on the piggybacked part in the resources carrying the SCI, to retrieve the decoding result feedback for the SL data transmission in step <NUM>. In another aspect, in response to receiving the SCI from the Rx UE <NUM>, the third UE <NUM> detects that the SCI is directed to itself according to the destination ID thereof, and therefore retrieve the SA for the SL data transmission from the Rx UE <NUM>. Although the third UE <NUM> is shown differently from the Tx UE <NUM>, it should be understood by the one skilled in the relevant art that the third UE <NUM> can be a same entity with the Tx UE, with the SL data from the Rx UE <NUM> being independent with that from Tx UE <NUM>.

<FIG> is a flow diagram illustrating a method for a Tx UE under the context of <FIG> according to one embodiment. The Rx UE is also named as the second apparatus in this embodiment.

The method begins at S701, in which the Tx UE reserves resources for one or more SL data transmissions and resources for decoding result feedbacks corresponding to the one or more SL data transmissions. In step S702, the Tx UE transmits sidelink control information (SCI) to a Rx UE, which indicates the resources for the SL data transmissions.

In some embodiments, the Tx UE reserves resources for the SCI transmission, wherein the SCI indicates the resources for current SL data transmission and the resources for next SL data transmission.

In some embodiments, the reserved resources for the decoding result feedback are derived from at least one of the resources for the SL data transmissions and resources for the SCI transmissions. Alternatively, the reserved resources for the decoding result feedback are indicated in the SCI transmitted to the second apparatus.

In step S703, the Tx UE transmits SL data to the Rx UE. In step S704, the Tx UE determine if a positive feedback of ACK is received.

If the Tx UE doesn't receive an ACK ("N" in step S704), the Tx UE determine if a maximum number of the SL data transmissions is reached. If the maximum number of the SL data transmissions has not been reached ("N" in step S706), the method proceeds back to step S702, in response to the SCI indicating the resources for current SL data transmission and the resources for next SL data transmission. If the maximum number of the SL data transmissions has been reached ("Y" in step S706), the method proceeds to S709. In step S709, the Tx UE determines that the transmission of SL data is failed. If the Tx UE receives an ACK ("Y" in step S704), the Tx UE determines if a pre-emption indicator is received in step S705.

If the Tx UE doesn't receive a pre-emption indicator ("N" in step S705), the method proceeds to S708. In step S708, optionally, the Tx UE transmits another data if any, in the reserved resources. If the Tx UE receives a pre-emption indicator("Y" in step S705), the method proceeds to S707. In step S707, the Tx UE receives SL data from Rx UE in the reserved resource.

The Tx UE receives a pre-emption indicator in the resources for the decoding result feedback, which indicates the second apparatus such as the Rx UE will pre-empt the reserved resources for the SL data transmission, in the case that the decoding result feedback is a positive feedback.

In one embodiment, a field for the pre-emption indicator is included in SCI from the second apparatus. In another embodiment, a field for a flag, which indicates that a field for the decoding result feedback indicates the pre-emption indicator, is included in SCI from the second apparatus. In yet another embodiment, the pre-emption indicator is piggybacked in the resources for the decoding result feedback.

The method further includes receiving SCI from the second apparatus, which indicates a configuration for SL data transmissions from the second apparatus.

The SCI transmitted to the second apparatus includes a pre-emption enabling indicator, which indicates whether the reserved resources for the SL data transmission are able to be pre-empted.

In some embodiments, the decoding result feedback is received, which is piggybacked in resources for SCI transmitted from the second apparatus to another apparatus, as described in combination of <FIG>. In other embodiments, the decoding result feedback is received, which is included in SCI transmitted from the second apparatus to another apparatus, as described in combination of <FIG>.

<FIG> is a flow diagram illustrating a method for a Tx UE under the context of <FIG> according to another embodiment. The Rx UE is also named as the second apparatus in this embodiment. The steps other than step <NUM> in <FIG> are same with the steps other than step <NUM> in <FIG>. Therefore, only step <NUM> are described hereinafter.

As described for <FIG> and <FIG>, in some embodiments, the SCI indicates the resources for the one or more SL data transmissions, wherein, the SCI indicates the resources for the one or more SL data transmission using a time offset between successive SL data transmissions and a number of the one or more SL data transmissions.

If the Tx UE doesn't receive an ACK ("N" of S724), the Tx UE determine if a maximum number of the SL data transmissions is reached. If he maximum number of the SL data transmissions has not been reached ("N" in step S726), the method proceeds to S723, in response to the SCI indicating the resources for the one or more SL data transmission. If the maximum number of the SL data transmissions has been reached ("Y" in step S726), the method proceeds to S729. In step S729, the Tx UE determines that the transmission of SL data is failed. If the Tx UE receives an ACK ("Y" in step S724), the Tx UE determines if a pre-emption indicator is received in step S725.

<FIG> is a flow diagram illustrating a method for a Rx UE under the context of <FIG> according to one embodiment. The Tx UE is also named as the first apparatus in this embodiment.

The method begins at S801, the Rx UE receives SCI, which indicates resources for the SL data transmissions from a first apparatus such as the Tx UE, and reserves the resources for the SL data transmissions and resources for decoding result feedbacks corresponding to the SL data transmissions at S802.

In some embodiments, the Rx UE learns the resources for the SCI transmission reserved by the Tx UE.

In some embodiments, the Rx UE reserves resources for the SCI transmission, wherein the SCI indicates the resources for current SL data transmission and the resources for next SL data transmission.

In some embodiments, the reserved resources for the decoding result feedback are derived from at least one of the resources for the SL data transmissions and resources for the SCI transmissions. The reserved resources for the decoding result feedback are indicated in the SCI received from the first apparatus.

At S803, the Rx UE determines if the SL data is correctly decoded. If the Rx UE determines the SL data is not correctly decoded ("N" in step S803), the method proceeds to S805, in which the Rx UE transmits NACK at S805. Then the method may return to S801 in response to the SCI indicating the resources for current SL data transmission and the resources for next SL data transmission, in the case that the maximum number of SL data transmissions has not been reached from a view of Tx UE. If the Rx UE determines the SL data is correctly decoded ("Y" in step S803), the method proceeds to S804, in which the Rx UE determines if it has data to be transmitted to the Tx UE.

If the Rx UE determines it does have data to be transmitted to the Tx UE ("Y" in step S804), the method proceeds to S806, in which the Rx UE determines if the pre-emption for the reserved resources is allowed by Tx UE. If the Rx UE determines it doesn't have data to be transmitted to the Tx UE ("N" in step S804), the method proceeds to S810, in which the Rx UE transmits the decoding result feedback to the Tx UE.

If the Rx UE determines that the pre-emption for the reserved resources is allowed by Tx UE ("Y" in step S806), the method proceeds to S807, in which the Rx UE determines if the priority of data to be transmitted satisfy pre-defined rules for pre-emption. If the Rx UE determines that the priority of data to be transmitted does not satisfy pre-defined rules ("N" in step S807), or the pre-emption for the reserved resources is not allowed by the Tx UE ("N" in step S806), the method proceeds to S810, in which the Rx UE transmits the decoding result feedback to the Tx UE.

If the Rx UE determines that the priority of data satisfies the predefined rules ("Y" in step S807), the method proceeds to S808, in which the Rx UE transmits an ACK and a pre-emption indicator to the Tx UE. Then Rx UE transmits the data in step S809.

The Rx UE transmits a pre-emption indicator in the resources for the decoding result feedback, which indicates the reserved resources for the SL data transmission from the first apparatus will be pre-empted, in the case that the decoding result feedback is a positive feedback.

Further, the Rx UE transmits a pre-emption indicator, in the case that a priority of SL data transmission to the first apparatus meets one or more followings pre-defined rules: higher than a priority of SL data transmission from the first apparatus, higher that a pre-defined priority. It should be understood by the one skilled in the relevant art that the pre-defined rules can be configured from gNB.

The Rx UE transmits a pre-emption indicator, in the case where a pre-emption enabling indicator, which is included in the received SCI, indicates that the reserved resources for the SL data transmissions are able to be pre-empted.

In one embodiment, a field for the pre-emption indicator is included in SCI to the first apparatus. In another embodiment, a field for a flag, which indicates that a field for the decoding result feedback indicates the pre-emption indicator, is included in SCI to the first apparatus. In yet another embodiment, the pre-emption indicator is piggybacked in the resources for the decoding result feedback.

The method further includes transmitting SCI to the first apparatus, which indicates a configuration for SL data transmissions to the first apparatus.

In some embodiments, the decoding result feedback may be transmitted, which is piggybacked in resources for SCI transmitted to another apparatus, as described in combination of <FIG>. In other embodiments, the decoding result feedback may be transmitted, which is included in SCI transmitted to another apparatus, as described in combination of <FIG>.

<FIG> is a flow diagram illustrating a method for a Rx UE under the context of <FIG> according to another embodiment. The Tx UE is also named as the first apparatus in this embodiment. The steps other than step <NUM> in <FIG> are same with the steps other than step <NUM> in <FIG>. Therefore, only step <NUM> is described hereinafter.

As described for <FIG> and <FIG>, in some embodiments, the SCI indicates the resource for one or more SL data transmissions, wherein the SCI indicates the resources for the one or more SL data transmission using a time offset between successive SL data transmissions and a maximum number of the SL data transmissions.

At S823, the Rx UE determines if the SL data is correctly decoded. If the Rx UE determines the SL data is not correctly decoded ("N" in step S823), the method proceeds to S825, in which the Rx UE transmits NACK at S825. Then the method may returns to S822 in response to the SCI indicating the resources for the one or more SL data transmissions, in the case that the maximum number of SL data transmissions has not been reached from a view of Tx UE. If the Rx UE determines the SL data is correctly decoded ("Y" in step S823), the method proceeds to S824, in which the Rx UE determines if it has data to be transmitted to the Tx UE.

<FIG> is a schematic diagram illustrating exemplary association relationships between PSCCH and its associated PSSCH. Resources occupied by PSCCH are represented by the shaded blocks, while resources occupied by PSSCH are represented by the blank blocks.

Option <NUM> is the case that PSCCH and the associated PSSCH are transmitted using non-overlapping time resources. The Option <NUM> may include two cases, that is, Option 1A and Option 1B as illustrated in the <FIG>.

Option 1A is the case that the frequency resources used by the two channels, such as PSCCH <NUM> and PSSCH <NUM>, are the same.

Option 1B is the case that the frequency resources used by the two channels, such as PSCCH <NUM> and PSSCH <NUM>, can be different.

Option <NUM> is the case that PSCCH <NUM> and the associated PSSCH <NUM> are transmitted using non-overlapping frequency resources in the all the time resources used for transmission. The time resources used by the two channels are the same.

Option <NUM> is the case that a part of PSCCH <NUM> and the associated PSSCH <NUM> are transmitted using overlapping time resources in non-overlapping frequency resources, but another part of the associated PSSCH and/or another part of the PSCCH are transmitted using non-overlapping time resources.

Here, the PSCCH and PSSCH can be in the same time slot and/or in different time slot.

<FIG> is a schematic block diagram illustrating components of a relay/remote UE according to one embodiment.

Tx/Rx UE1000 is an embodiment of Tx/Rx UE described from <FIG>. Furthermore, Tx/Rx UE <NUM> may include a processor <NUM>, a memory <NUM>, and a transceiver <NUM>. In some embodiments, Tx/Rx UE <NUM> may include an input device <NUM> and/or a display <NUM>. In certain embodiments, the input device <NUM> and the display <NUM> may be combined into a single device, such as a touch screen.

The processor <NUM> is communicatively coupled to the memory <NUM>, the input device <NUM>, the display <NUM>, and the transceiver <NUM>.

In some embodiments, the processor <NUM> controls the transceiver <NUM> to transmit UL signals to Network Equipment and/or receive DL signals from Network Equipment. For example, the processor <NUM> may control the transceiver <NUM> to transmit CSI/RSRP as a SL channel measurement result to a network equipment such as eNB in the case that UE <NUM> is a relay UE. In another example, the processor <NUM> may control the transceiver <NUM> to receive a higher layer signaling such as the predefined rules for the pre-emption of the reserved resources, as described above. In certain embodiments, the processor <NUM> may monitor DL signals received via the transceiver <NUM> for specific messages. For example, the processor <NUM> may generate and transmit a pre-emption indicator to the Tx UE.

The memory <NUM>, in one embodiment, is a computer-readable storage medium. For example, the memory <NUM> may include RAM, including dynamic RAM ("DRAM"), synchronous dynamic RAM ("SDRAM"), and/or static RAM ("SRAM"). For example, the memory <NUM> may include a hard disk drive, flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory <NUM> stores data relating to the pre-emption indicator received from the Rx UE. In some embodiments, the memory <NUM> also stores program code and related data, such as an operating system or other controller algorithms operating on Tx/Rx UE <NUM>.

Tx/Rx UE <NUM> may optionally include an input device <NUM>. In some embodiments, the input device <NUM> may be integrated with the display <NUM>, for example, as a touch screen or similar touch-sensitive display. In some embodiments, the input device <NUM> includes a touch screen such that text may be inputted using a virtual keyboard displayed on the touch screen and/or by handwriting on the touch screen. In certain embodiments, the input device <NUM> may include one or more sensors for monitoring an environment of Tx/Rx UE <NUM>.

Tx/Rx UE <NUM> may optionally include a display <NUM>. For example, the display <NUM> may include, but is not limited to being, an LCD display, an LED display, an OLED display, a projector, or a similar display device capable of outputting images, text, or the like, to a user. As another non-limiting example, the display <NUM> may include a wearable display such as a smart watch, smart glasses, a heads-up display, or the like.

In certain embodiments, the display <NUM> may include one or more speakers for producing sound. For example, the input device <NUM> and display <NUM> may form a touch screen or similar touch-sensitive display.

The transceiver <NUM>, in one embodiment, is configured to communicate wirelessly with the network equipment such eNB. In certain embodiments, the transceiver <NUM> comprises a transmitter <NUM> and a receiver <NUM>. The transmitter <NUM> is used to transmit UL communication signals to the network equipment and the receiver <NUM> is used to receive DL communication signals from the network equipment. For example, the transmitter <NUM> may transmit SCI including SA for the SL data transmission. As another example, the receiver <NUM> may receive the pre-emption indicator for pre-empting the reserved resources.

The transmitter <NUM> and the receiver <NUM> may be any suitable type of transmitter or receiver, respectively. Although only one transmitter <NUM> and one receiver <NUM> are illustrated, the transceiver <NUM> may have any suitable number of transmitters <NUM> and receivers <NUM>. For example, in some embodiments, Tx/Rx UE <NUM> includes a plurality of transmitter <NUM> and receiver <NUM> pairs for communicating on a plurality of wireless networks and/or radio frequency bands, each transmitter <NUM> and receiver <NUM> pair configured to communicate on a different wireless network and/or radio frequency band than the other transmitter <NUM> and receiver <NUM> pairs.

Claim 1:
A method performed by a first apparatus, comprising:
reserving (<NUM>, <NUM>) resources for one or more sidelink, SL, data transmissions and resources for decoding result feedback corresponding to the one or more SL data transmissions;
transmitting (<NUM>, <NUM>) sidelink control information, SCI, to a second apparatus, which indicates the resources for the one or more SL data transmissions; and
receiving (<NUM>, <NUM>), from the second apparatus, at least one of the decoding result feedback and a pre-emption indicator;
further comprising receiving the pre-emption indicator in the resources for the decoding result feedback, which indicates the second apparatus will pre-empt the reserved resources for the one or more SL data transmissions, in the case that the decoding result feedback is a positive feedback.