D2D Signal Measurement for Relay Selection in Out-of-Coverage UEs
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Solution Overview
Problem
User equipment (UE) out of network coverage faces challenges in communicating effectively with the network due to weak or no connection, and existing methods for selecting a relay UE within network coverage are not efficient in ensuring reliable communication.
Innovation Solution
A method where a UE out of network coverage measures the signal strength of device-to-device (D2D) signals from proximate UEs within network coverage and selects the UE with the strongest signal as a relay to establish communication with the network, using resource elements for reference signals and data parts of D2D signals for measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE out of network coverage attempts to communicate with the network, then connectivity is established, but the connection quality is weak or unreliable
Solution Approach 1:
The patent introduces a relay UE as an intermediary device between the out-of-coverage UE and the network. The relay UE receives D2D signals from the remote UE and forwards them to the network, enabling indirect communication. This mediator approach allows the remote UE to establish reliable connectivity through the relay UE's stronger network connection, directly resolving the signal weakness issue while maintaining connection reliability.
2Adaptability or versatility
If multiple candidate relay UEs are available, then selection options increase, but the complexity of selecting the best relay increases
Solution Approach 1:
The patent replaces complex manual or algorithmic relay selection mechanisms with a simplified signal strength-based selection system. The remote UE measures RSRP values of D2D signals from multiple candidate relay UEs and automatically selects the relay with the strongest signal. This substitution of complex decision-making with a straightforward physical measurement approach reduces selection complexity while maintaining adaptability to different network conditions.
Solution Approach 2:
The patent changes the selection parameter from complex multi-criteria evaluation to a single dominant parameter: signal strength (RSRP). By focusing solely on signal strength measurement and comparison, the system simplifies the relay selection process while still achieving optimal connectivity. The UE compares RSRP values and selects the relay with the highest value, eliminating the need for complex weighting and evaluation algorithms.
3Measurement precision
If signal strength measurement is performed on reference signals, then measurement accuracy improves, but the ability to assess actual data transmission quality decreases
Solution Approach 1:
The patent merges reference signal-based RSRP measurement with data signal quality assessment into a unified relay selection criterion. The system performs RSRP measurement on reference signals for accurate signal strength quantification, then uses this measurement to evaluate the overall D2D link quality for data transmission. This combination allows the system to leverage the precision of reference signal measurement while still making informed decisions about actual data transmission capability.
Data Source
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AI summary
An efficient approach for a mobile device apparatus that is out of network coverage to communicate with the network is desired. The apparatus may be a user equipment (UE). The apparatus receives one or more device-to-device (D2D) signals respectively from one or more proximate UEs. The apparatus measures signal strength of the one or more D2D signals based on signal strength of one or more resource elements used for receiving one and/or more reference signals of the one or more D2D signals or signal strength of one or more resource elements used for receiving one or more data parts of the one or more D2D signals. The apparatus selects one of the one or more proximate UEs as a relay UE based on the measurement of the signal strength of the one or more D2D signals, to communicate with the base station via the selected relay UE.