FIELD

The subject matter disclosed herein relates generally to wireless communication and more particularly relates to resource collision avoidance on Sidelink.

BACKGROUND

The following abbreviations and acronyms are herewith defined, at least some of which are referred to within the following description.

Third Generation Partnership Project (“3GPP”), Positive-Acknowledgment (“ACK”), Channel State Information (“CSI”), Control Channel (“CCH”), Dynamic Scheduling (“DS”), Device-to-Device (“D2D”), further enhancement Device-to-Device (“feD2D”), Downlink Control Information (“DCI”), Downlink (“DL”), 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 Identity (“RNTI”), Identity Radio Resource Control (“RRC”), Resource Reservation Field (“RRF”), 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”), 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”), Vehicle-to-Vehicle (“V2V”) and Vehicle-to-Everything (“V2X”), Vehicle-to-Infrastructure/Network (“V2I/N”), Vehicle-to-Pedestrian (“V2P”).

In order to expand the LTE system to the automotive industry, the initial standard on support for V2V services was completed in September 2016. Further enhancements included in Release 14 (Rel-14), which focus on additional V2X operation scenarios leveraging the cellular infrastructure, was completed in March 2017. Currently, 3GPP TSG SA (Service and System Apects) WG1 (Working Group 1) is working on the enhancement of 3GPP support for V2X services in a work item of FS_eV2X (study for enhanced V2X). SA WG1 has identified 25 use cases for advanced V2X services which are categorized into four groups of use cases: vehicles platooning, extended sensors, advanced driving and remote driving. The consolidated requirements for each group are captured in TR 22.886.

In Release 15 (Rel-15), it is expected to enhance the Cellular-based V2X services (V2V, V2I/N, and V2P) as identified in TR 22.886 in a holistic and complementary manner as respect to V2X in Rel-14, which will involve enhancements for both Uu interface and PC5 interface.

One of the objectives for this study is radio resource pool sharing between UEs using mode 3 and UEs using mode 4, wherein UEs using mode 3 and mode 4 are also referred as mode 3 UE(s) and mode 4 UE(s) respectively herein. Radio resource for Mode 3 UE is scheduled by eNB, while radio resource for Mode 4 UE is autonomously selected from a resource pool by itself, as defined in Rel-14. In Rel-14, resource pools for mode 3 and mode 4 are orthogonal configured to avoid resource collision between mode 3 and mode 4. The reason of the orthogonal configuration is that there is no indication for SA to indicate the reserved resource for mode 3 UE, that is, the resource reservation field in SCI is set to be 0. In another aspect, mode 4 UE, which autonomously select radio resources, cannot get the knowledge of reserved resource for mode 3 UE. Thus, the resource collision is avoided by orthogonal configuration of resource pools in Rel-14, which has an impact on the resource utilization.

In Rel-15, radio resource pool sharing between mode 3 UE and mode 4 UE is studied, to enhance the resource utilization, as well as to solve some problems of resource collision, which is caused by the lack of resource coordination between mode 3 UE and mode 4 UE, e.g. pre-configured resource for mode 4 UE has overlap with resource for mode 3 UE configured by eNB, or inter-PLMN case etc.

In another aspect, it is expected that the resource coordination between mode 3 UE and mode 4 UE reuse the legacy SA format, which can be decoded by Rel-14 UEs, without causing significant degradation to Rel-14 PC5 operation compared to that of Rel-14 UEs.

BRIEF SUMMARY

Enhancements to resource pool sharing between mode 3 UE and mode 4 UE require increased resource utilization, as well as the avoidance for resource collision. However in the case that resource for mode 3 UE is scheduled by eNB while resource for mode 4 UE is autonomously selected from a resource pool, mode 4 UE may have no knowledge of reserved resource for mode 3 UE by eNB. Moreover, significant signaling overhead is not expected, and the compatibility for Rel-14 UEs are need to be considered. Thus, it is preferred that the legacy SA format is reused to avoid the resource collision.

Method and apparatus for resource collision avoidance on sidelink are disclosed. One method of mode 3 UE for resource collision avoidance on sidelink includes determining reserved resource on SL for a following SL transmission; transmitting information of the reserved resource to a mode 4 UE in a resource reservation field in SCI.

Further, the reserved resource on SL is determined according to DCI received from a base station.

Further, a resource guarantee indication, which indicates whether the reserved resource indicated in the resource reservation field in the SCI can be occupied by the mode 4 UE, is transmitted to the mode 4 UE.

In another aspect, one method of a network equipment for resource collision avoidance on sidelink includes determining reserved resource on SL for a following SL transmission; transmitting information of the reserved resource to a mode 3 UE in DCI.

Further, a resource reservation field in the DCI scrambled with SL-V-RNTI is used to transmit the information of the reserved resource and set a reserved resource field in SCI.

Further, a SL SPS configuration field in the DCI scrambled with SL-SPS-V-RNTI is used to transmit the information of the reserved resource, and a SL SPS configuration index included in the SL SPS configuration field in the DCI is used to set a reserved resource field in SCI.

In another aspect, one method of mode 4 UE for resource collision avoidance on sidelink includes receiving information of reserved resource on SL from a mode 3 UE in a resource reservation field in SCI; determining existence of resource collision on SL.

Further, resource reselection is performed in the case that the reserved resource has collision with resource used by the mode 4 UE for an ongoing SL transmission.

Further, the reserved resource is excluded from a resource pool in the case that the reserved resource has not collision with resource used by the apparatus for an ongoing SL transmission.

The method and apparatus herein not only increase the resource utilization by radio resource sharing between mode 3 UEs and mode 4 UEs, but also resolve a problem of resource collision in resource sharing scenario. Further, the compatibility for Rel-14 UEs is considered without introducing significant signaling overhead due to the reuse of legacy SA format.

