Relay UE Link-Layer Identifier Exchange for Peer Discovery
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Solution Overview
Problem
In a New Radio (NR) system, a terminal device with ProSe capability cannot correctly discover a peer terminal via a relay terminal due to the inability to obtain the link layer identifier of the peer terminal, hindering the establishment of a short-range communication connection.
Innovation Solution
The terminal device obtains the link layer identifier of the peer terminal via a relay UE by transmitting and receiving messages with a data packet header that carries the necessary identifiers, enabling correct discovery and connection establishment through the relay UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal device camps on a cell with a large reference signal received power (RSRP) difference between SSB and CSI-RS, then the terminal can achieve good signal strength, but the terminal may camp on a wrong cell and fail to receive network notification of cell dormancy
Solution Approach 1:
The patent changes the parameter used for cell camping decision from RSRP (reference signal received power) to SS-RSRP (SS block reference signal received power) when the RSRP difference between SSB and CSI-RS exceeds a threshold. This parameter change ensures the terminal camps on the correct cell while still achieving good signal strength, resolving the contradiction between camping accuracy and information reception.
2Loss of information
If the network sends cell dormancy notification through DCI format 2_6, then the terminal can be notified of cell dormancy, but the terminal may miss the notification if camped on a wrong cell
Solution Approach 1:
The patent applies preliminary action by having the terminal determine whether the RSRP difference exceeds a threshold before camping, and adjust the camping criterion accordingly. This preliminary check ensures the terminal camps on the correct cell from the beginning, preventing missed notifications later.
3Speed
If the terminal uses RSRP as the camping criterion, then the terminal can achieve fast cell selection, but the terminal may camp on a wrong cell with poor CSI-RS signal
Solution Approach 1:
The patent applies dynamics by making the cell camping criterion adaptive: using RSRP when the RSRP difference is within the threshold (fast selection), and using SS-RSRP when the difference exceeds the threshold (accurate selection). This dynamic adjustment resolves the contradiction between selection speed and accuracy.
Data Source
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AI summary
The embodiments of the present disclosure provide a wireless communication method and a terminal device. The terminal device can obtain a link layer identifier of a peer terminal via a Relay UE, and discover the peer terminal via the Relay UE, such that a short-range communication connection can be correctly established between the two terminals via the Relay UE. The wireless communication method includes: receiving, by a relay terminal, a first message transmitted by a first terminal, a data packet header of the first message carrying a link layer identifier of the first terminal; and transmitting, by the relay terminal, a second message including the link layer identifier of the first terminal, a data packet header of the second message carrying a link layer identifier of the relay terminal.