PC5 Relay Broadcast of Selected System Information for OoC UE Selection
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Solution Overview
Problem
Conventional wireless communication systems face challenges in managing relay UE device selection and reselection for out-of-coverage (OoC) UE devices, as they lack dynamic updates of system information and frequency priority, leading to inefficient network access and resource management.
Innovation Solution
Relay UE devices transmit selected system information in sidelink discovery messages, which is a subset of system information received from a cell, enabling remote UE devices to make informed relay selection/reselection based on current network information, including frequency priority and link quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay UE devices transmit selected system information in PC5 broadcast messages, then remote UE devices can obtain up-to-date system information for informed relay selection, but the complexity of message transmission and information management increases
Solution Approach 1:
The system segments system information into different categories (minimum system information and other system information) and transmits them through different channels. Minimum system information is included in PC5 broadcast messages for relay selection, while other system information is obtained from the cell. This segmentation allows remote UE devices to receive critical relay selection information without being overwhelmed by complete system information, reducing message complexity while maintaining reliability.
Solution Approach 2:
The invention extracts only the essential system information parameters needed for relay selection (such as frequency priority, cell identity, and basic access parameters) from the complete system information and transmits them in PC5 broadcast messages. This extraction approach provides remote UE devices with sufficient information for informed relay selection while minimizing the complexity of the transmitted messages.
2Reliability
If remote UE devices receive complete system information from all candidate relay UE devices, then they can make optimal relay selection, but the information processing load and time consumption increase
Solution Approach 1:
The system implements partial action by transmitting only the most critical system information parameters in PC5 broadcast messages rather than complete system information. This allows remote UE devices to perform initial relay selection based on essential parameters (frequency priority, cell identity, basic access conditions) quickly, reducing the time required for relay selection while still enabling optimal decisions through the inclusion of key parameters.
3Loss of information
If relay UE devices transmit frequent updates of system information, then remote UE devices maintain current network information, but the network congestion and resource consumption increase
Solution Approach 1:
The system implements periodic action by having relay UE devices transmit system information updates at specific intervals or when significant changes occur, rather than continuously. This periodic transmission approach ensures that remote UE devices receive current system information for accurate relay selection while minimizing network congestion and resource consumption by avoiding unnecessary frequent transmissions.
4Ease of operation
If out-of-coverage UE devices use conventional relay selection methods, then they can connect to the network, but they lack frequency priority information leading to inefficient network access
Solution Approach 1:
The system implements preliminary action by including frequency priority information and basic system information parameters in PC5 broadcast messages before the remote UE device establishes a connection through the relay. This allows out-of-coverage UE devices to pre-evaluate candidate relay devices based on frequency priority and network conditions, enabling more efficient network access by selecting relays that provide optimal paths to the network, rather than simply connecting to any available relay.
Data Source
AI summary
A relay user equipment (UE) device transmits selected system information in a sidelink discovery message where the selected system information is a subset of system information received from a cell at the relay UE device. A remote UE device receiving the sidelink discovery message with the selected system information obtains at least system information for accessing the cell where such system information may not be available directly from the cell. The remote UE receiving select system information from each of a plurality of candidate relay UE devices manages relay selection/reselection at least partially based on the selected system information.