Relay UE RRC Connection Forwarding
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Solution Overview
Problem
There is a need for a solution to establish a Radio Resource Control (RRC) connection between a Remote UE and an eNB through a Relay UE while reusing the current RRC Connection Establishment procedure, avoiding the MAC random access procedure, and ensuring efficient handling of control plane signaling in evolved ProSe UE-to-Network Relay for layer 2 relaying.
Innovation Solution
The method involves transmitting a request for an RRC connection from a first wireless device to a radio network node through a second wireless device, using an already established RRC signaling connection, and configuring relayed signaling radio bearers to establish and maintain the RRC connection, thereby avoiding the MAC random access procedure and enabling efficient control plane signaling relaying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the MAC random access procedure is used for RRC connection establishment in relay scenarios, then the connection can be established, but contention occurs and efficiency is reduced
Solution Approach 1:
The patent introduces a relay UE as an intermediary to forward RRC signaling messages between the remote UE and the eNB. This mediator enables the remote UE to establish an RRC connection indirectly through the relay UE's existing signaling connection, avoiding the need for the remote UE to perform MAC random access to the eNB directly. The relay UE acts as a bridge that carries RRC messages over the sidelink interface, thereby improving connection establishment efficiency and reducing time loss.
2Adaptability or versatility
If layer 3 relay is used, then IP layer relaying is achieved, but control plane signaling cannot be distinguished from user plane traffic
Solution Approach 1:
The patent segments the relay functionality into distinct layers: the remote UE and relay UE maintain separate RRC contexts, and the relay UE separately handles control plane signaling forwarding. This segmentation allows the system to provide relay adaptability while preserving the distinction between control plane and user plane traffic. The relay UE can identify and forward control plane messages based on message type indicators, ensuring that control signaling is not lost or confused with user data.
3Adaptability or versatility
If a new RRC connection establishment procedure is designed for relay scenarios, then relay-specific requirements are met, but device complexity and implementation difficulty increase
Solution Approach 1:
The patent makes the existing RRC connection establishment procedure universal by enabling it to function in both direct and relay scenarios. The same RRC messages and procedures are used, but with the added capability of being forwarded by a relay UE. This multi-functionality approach allows the RRC protocol to handle both direct UE-to-eNB connections and relayed UE-to-eNB connections using the same procedure, thereby avoiding the need for complex relay-specific procedures while still meeting relay requirements.
Data Source
AI summary
A method for establishing a radio resource control connection between a first wireless device and a radio network node, comprises transmitting a request for a radio resource control connection towards the radio network node from the first wireless device to a second wireless device. Then, the second wireless device forwards the request for a radio resource control connection towards the radio network node to the radio network node. The forwarding by the second wireless device uses an already established radio resource control signaling connection between the second wireless device and the radio network node.