D2D Relay Selection via Link Quality Filtering
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Solution Overview
Problem
Current methods for measuring device-to-device (D2D) link quality in 5G communication systems are inadequate, as they cannot identify and filter link qualities for specific relay UEs due to the lack of known IDs and unique discovery resources, making it difficult to select the best relay UE for out-of-coverage remote UE communication.
Innovation Solution
A method and apparatus that involve receiving and decoding discovery data in predetermined resources, measuring link qualities for demodulation reference signals, and filtering the link quality corresponding to a specific relay UE ID, allowing for effective selection of the best relay UE for D2D communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If discovery data is transmitted without unique identification, then discovery coverage is expanded, but link quality measurement precision for specific relay UEs deteriorates
Solution Approach 1:
The patent applies local quality by introducing relay UE-specific identification information (relay UE ID) into the discovery data structure. This allows the discovery signal to maintain broad coverage while enabling precise local identification and measurement of link qualities for specific relay UEs. The relay UE ID is incorporated in the discovery message at the MAC layer, allowing receivers to filter and measure link qualities for particular relay UEs while still using the same discovery resources for general coverage.
2Measurement precision
If relay UE ID is added to discovery data, then link quality filtering capability is improved, but device complexity increases
Solution Approach 1:
The patent applies partial action by adding only the necessary relay UE ID information to the discovery data without redesigning the entire discovery protocol. The relay UE ID is incorporated as an additional field in the discovery message, allowing link quality filtering capability to be improved with minimal changes to the existing protocol structure. This partial modification approach avoids excessive complexity while achieving the desired filtering functionality.
3Adaptability or versatility
If multiple relay UEs are monitored simultaneously, then relay selection flexibility is improved, but measurement processing load increases
Solution Approach 1:
The patent applies segmentation by enabling the receiver to divide the measurement process into separate operations for different relay UEs. Through the relay UE ID field in discovery data, the receiver can segment the monitoring process to focus on specific relay UEs of interest, rather than processing all discovered relay UEs uniformly. This segmentation allows flexible relay selection while managing processing load by targeting measurements toward relevant relay UEs only.
Data Source
AI summary
The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. The method for device to device communication according to the present disclosure comprises: a step of receiving, by a terminal, search data from search resources for relay search within a specified search-receiving resource pool, and decoding the same; a step of measuring, by the terminal, link qualities of the search resources which deliver demodulation reference signals, from the search resources corresponding to successfully decoded search data; and a step of filtering a link quality corresponding to an identifier of a specific relay among the measured link qualities.