WO2023065107A1

WO2023065107A1 - Methods and apparatus of si acquisition for sidelink relay operation

Info

Publication number: WO2023065107A1
Application number: PCT/CN2021/124650
Authority: WO
Inventors: Xuelong Wang
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2021-10-19
Filing date: 2021-10-19
Publication date: 2023-04-27
Also published as: CN115996445A

Abstract

This disclosure describes methods and apparatus of supporting SI acquisition by the Remote UE from the network for the updated SIBs during sidelink relaying operation. Remote UE provides his interest of SIBs to the Relay UE during PC5 RRC establishment. Relay UE sends only the updated SIBs based on the Remote UE's SIB interest when the Relay UE gets updates SIBs from the network.

Description

METHODS AND APPARATUS OF SI ACQUISITION FOR SIDELINK RELAY OPERATION

FIELD OF THE INVENTION

The present disclosure relates generally to communication systems, and more particularly, the method of enabling SI acquisition to support sidelnk relay operation within wireless network.

BACKGROUND OF THE INVENTION

Various cellular systems, including both 4G/LTE and 5G/NR systems, may provide a sidelink relaying functionality, which allows a Remote user equipments (UEs) in the system to communicate with wireless cellular system via a second Relay UE. A variety of applications between Remote UE and the network may rely on communication over the relaying channel provided by Relay UE, such as vehicle-to-everything (V2X) communication, public safety (PS) communication, and so on. During sidelink relaying operation, the network may update the System Information (SI) . Then the Relay UE and Remote UE may need to acquire the updated SI.

SUMMARY OF THE INVENTION

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.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a Remote UE during sidelink relaying operation. The Remote UE sends the list of SIBs interested to the Relay UE via existing PC5-RRC message or a new PC5-RRC message during PC5 RRC establishment. After Relay UE receives this list, Relay UE maintains the list within the Remote UE context during the lifetime of Remote UE (i.e. as long as the Remote UE is still connected with Relay UE via PC5) . In this way, when Relay UE acquires the updated SI from the network, Relay UE only sends to Remote UE the SIBs interested by the Remote 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 drawings 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 (a) is a schematic system diagram illustrating an exemplary Base Station (i.e. BS) , in accordance with certain aspects of the present disclosure.

FIG. 1 (b) is a schematic system diagram illustrating an exemplary UE, in accordance with certain aspects of the present disclosure.

FIG. 2 illustrates an exemplary NR wireless communication system, in accordance with certain aspects of the present disclosure.

FIG. 3 illustrates an exemplary NR UE-to-Network Relay network with an integration of two UEs, in accordance with certain aspects of the present disclosure.

FIG. 4 illustrates an exemplary SI acquisition procedure during sidelink relaying operation, in accordance with certain aspects of the present disclosure.

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.

Aspects of the present disclosure provide methods, apparatus, processing systems, and computer readable mediums for NR (new radio access technology, or 5G technology) or other radio access technology. NR may support various wireless communication services. These services may have different quality of service (QoS) requirements e.g. latency and reliability requirements. Figure 1 (a) is a schematic system diagram illustrating an exemplary Base Station (i.e. BS) . The BS may also be referred to as an access point, an access terminal, a base station, a Node-B, an eNode-B, a gNB, or by other terminology used in the art. As an example, base stations serve a number of mobile stations within a serving area, for example, a cell, or within a cell sector. The Base Station has an antenna, which transmits and receives radio signals. A RF transceiver, coupled with the antenna, receives RF signals from antenna, converts them to baseband signals, and sends them to processor. RF transceiver also converts received baseband signals from processor, converts them to RF signals, and sends out to antenna. Processor processes the received baseband signals and invokes different functions. Memory stores program instructions and data to control the operations of Base Station. Figure 1 (b) is a schematic system diagram illustrating an exemplary UE. The UE may also be referred to as a mobile station, a mobile terminal, a mobile phone, smart phone, wearable, an IoT device, a table let, a laptop, or other terminology used in the art. UE has an antenna, which transmits and receives radio signals. A RF transceiver, coupled with the antenna, receives RF signals from antenna, converts them to baseband signal, and sends them to processor. RF transceiver also converts received baseband signals from processor, converts them to RF signals, and sends out to antenna. Processor processes the received baseband signals and invokes different functional modules to perform features in UE. Memory stores program instructions and data to control the operations of mobile station. Figure 2 illustrates an exemplary NR wireless communication system. Different protocol split options between Central Unit and Distributed Unit of gNB nodes may be possible. In one embodiment, SDAP and PDCP layer are located in the central unit, while RLC, MAC and PHY layers are located in the distributed unit.

Figure 3 illustrates an exemplary NR UE-to-Network Relay network with an integration of two UEs in accordance with embodiments of the current invention. In NR, The Base Station is a gNB in NR system. The Relay UE in Figure 3 relays the traffic between the Base Station and the Remote UE. The Relay UE can operate as Layer 2 Relay or Layer 3 Relay. There is an NR Uu air interface between the Base Station and Relay UE. The NR Uu air interface includes both Downlink and Uplink. Optionally there is also an NR air interface between the Base Station and Remote UE. There is PC5 interface (i.e. Sidelink) between the Remote UE and the Relay UE.

In NR, the Short Messages (in paging DCI) is used to send SI modification and PWS notification to a UE. The Short Messages can be transmitted on PDCCH using P-RNTI with or without associated Paging message using Short Message field in DCI format 1_0. In order for Remote UE (s) to acquire the modified System Information (SI) from the network, following the transmission of a short message by the gNB, there are two candidate options. In the first option, the Relay UE receives the short message from the gNB, acquires the SI/PWS and sends it to the Remote UE. In the second option, the Relay UE receives the short message and forwards it to the Remote UE and then the Remote UE can acquire the SI by itself.

In the first option, by just sending the modified SI to Remote UE (in RRC_CONNECTED state or RRC_IDLE/RRC_INACTIVE state) , the potential signaling over Uu between Remote UE in RRC_CONNECTED state and gNB can be avoided, since the Remote UE (s) need not request the SI over Uu in an on-demand manner. The potential signaling over PC5 between Remote UE in RRC_IDLE/RRC_INACTIVE state and Relay UE can also be avoided, since the Remote UE (s) need not request the SIB over PC5 from Relay UE in on-demand manner..

In the first option, when Relay UE receives the short message from the network, the Relay UE first acquires the SI (e.g., by its own dedicatedSIBRequest when Relay UE is in RRC_CONNECTED state) and then forward the acquired SI over PC5-RRC. Since the Relay UE does not know which SI is of interest to the Remote UE (s) , it acquires and sends all the changed SI. As can be seen, the Relay UE sends all the SIBs, not just the ones that the Remote UE needs. This could result in more PC5 overhead where unnecessary SIBs are sent to many Remote UEs over PC5. There are several methods to handle this issue.

FIG. 4 illustrates an exemplary SI acquisition procedure during sidelink relaying operation, in accordance with certain aspects of the present disclosure. In the first alternative, as described in Figure 4, in step 1, during the establishment of PC5-RRC connection between Relay UE and Remote UE, the Remote UE says “here is the list of SIBs I’ m interested in” . And then in step 2, the Relay UE receives the short message notification from the network for SI modification and/or PWS notification. The Relay UE gets the updated SIBs from the network after step 2. Then in step 3, the Relay UE forwards only those SIBs to Remote UE according to the SIB interest list he received from Remote UE before. From PC5-RRC perspective, this alternative specifies a type of “SIB subscription” signaling exchange between Relay UE and Remote UE. In details, the Remote UE sends the list of SIBs interested to the Relay UE via existing PC5-RRC message or a new PC5-RRC message. After Relay UE receives this list, Relay UE maintains the list within the Remote UE context during the lifetime of Remote UE (i.e. as long as the Remote UE is still connected with Relay UE via PC5) . In this way, when Relay UE acquires the updates SI from the network, Relay UE only sends to Remote UE the SIBs interested by the Remote UE via PC5 RRC.

In the second alternative, the Remote UE provides his interested SIB list to the base station. The base station can records such request from Remote UE within its UE context. There are different ways for the Remote UE to provide his interested SIB list to the base station. As the first way, when the Remote UE establishes RRC connection with the base station, the Remote UE may request the SIBs from the network via dedicatedSIBRequest signaling over Uu interface. As the second way, when the Remote UE in RRC idle or RRC inactive state initiates the SI Request to the base station in on-demand manner to request the on-demand SIBs from the network over Uu interface. As the third way, when the Remote UE reports sidelink UE information to the gNB, the sidelink UE information can include an SIB list expressing the Remote UE’s SIB interest. As the fourth way, the Remote UE can report his SIB list expressing the Remote UE’s SIB interest to the gNB via an existing or new Uu RRC message.

In the second alternative, after base station knows the Remote UE’s SIB interest, then the base station can notify Remote UE’s SIB interests (e.g. a list of SIB) to the Relay UE via RRC message (e.g. RRCReconfiguration message) . There are different ways for the base station to provide Remote UE’s interested SIB list to the Relay UE. As the first way, when the base station configure the Relay UE to create the relaying channel for the Remote UE, the Remote UE’s interested SIB list can be included in the corresponding RRCReconfiguration message. As the second way, during the sidelink relaying operation, base station can provide the Remote UE’s interested SIB list to the Relay UE via a RRC message. After Relay UE receives Remote UE’s SIB interests (e.g. a list of SIB) , Relay UE maintains the list within the Remote UE context during the lifetime of Remote UE (i.e. as long as the Remote UE is still connected with Relay UE via PC5) . In this way, when Relay UE acquires the updates SI from the network, Relay UE only sends to Remote UE the SIBs interested by the Remote UE via PC5 RRC.

In the third alternative, when Relay UE receives the short message from the network, the Relay UE first acquires the SI (e.g., by its own dedicatedSIBRequest when Relay UE is in RRC_CONNECTED state) . And then Relay UE sends the list of changed SIB types (e.g. the number of the SIB) to the Remote UE. When Remote UE receives the list of changed SIB type, the Remote UE can request the changed SIB (s) via on-demand request over PC5, if the Remote UE needs the changed SIB (s) . In this way, the Relay UE only sends to Remote UE the SIBs interested by the Remote UE via PC5 RRC.

In the fourth alternative, during lifetime of PC5 RRC connection established between Relay UE and Remote UE, Relay UE records all of the SIB request as requested by Remote UE (e.g. via PC5 RRC message) , and based on this Relay UE maintain a list of SIBs interested by Remote UE. When Relay UE receives the short message from the network, the Relay UE first acquires the SI (e.g., by its own dedicatedSIBRequest when Relay UE is in RRC_CONNECTED state) and then sends to Remote UE only the SIBs interested by the Remote UE via PC5 RRC.

In the second option, there is only simple forwarding of short message over PC5 (e.g. by PC5 RRC message) from Relay UE to the Remote UE (s) . In this option, the Remote UE in RRC_CONNECTED state performs legacy dedicatedSIBRequest only for the interested SIBs. And this SI acquisition is transparent to the Relay UE and may be able to be sent along with normal data via the Relay UE. This option avoids unnecessary SI acquisition by the Relay UE during its reception of short message from the base station. However, with the increase of Remote UEs served by Relay UE, the dedicatedSIBRequest signaling over Uu sent by Remote UE (s) would increase proportionally. Furthermore, in this option, the Remote UE in RRC_IDLE/RRC_INACTIVE needs to request SI to the Relay UE. When there is any request from Remote UE for SI, Relay UE need request the SIB from the network. There would be potentially massive bi-directional signaling over PC5 between Remote UE (s) and Relay UE, since the Remote UE (s) need to separately request the SIB/SI over PC5 from Relay UE in on-demand manner. With the increase of Remote UEs served by Relay UE, the PC5 signaling would increase proportionally.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

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, ” “device, ” 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 method of wireless communication comprising:

SI acquisition by the Remote UE from the network for the updated SIBs during sidelink relaying operation, where the Relay UE provides the relaying channel between Remote UE and the network.
The method of claim 1, wherein the Remote UE provides his interest of SIBs to the Relay UE during PC5 RRC establishment.
The method of claim 2, wherein the interest of SIBs is transferred from Remote UE to the Relay UE via PC5 RRC message.
The method of claim 1, wherein the Relay UE stores the interest of SIBs of the Remote UE within the UE context.
The method of claim 4, wherein the Relay UE sends only the updated SIBs based on the Remote UE’s SIB interest stored within the UE context.