PSDCH Measurement via CRC Presumption for D2D Repeater Selection
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Solution Overview
Problem
Current 3GPP LTE systems lack an efficient method for selecting a terminal to operate as a repeater in device-to-device (D2D) communication, particularly in scenarios where terminals are outside or inside the coverage of a base station, affecting the reliability and accuracy of sidelink discovery channel measurements.
Innovation Solution
A method is introduced where a UE successfully decodes a PSDCH in a kth subframe and considers subsequent n−k subframes with successful cyclic redundancy checks (CRC) for measurement, using sidelink discovery reference signal received power (SD-RSRP) to select a suitable repeater, even if the CRC in the kth previous subframe is not successful, especially when n−k is smaller than a predetermined number.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRC checking is performed on every PSDCH subframe before measurement, then measurement reliability is improved, but measurement complexity and power consumption increase
Solution Approach 1:
The patent applies preliminary action by performing CRC checking only on the first successfully decoded PSDCH subframe (kth subframe) and then presuming successful CRC for subsequent subframes without actual decoding. This preliminary validation approach establishes measurement reliability based on initial successful decoding while avoiding the complexity of repeated CRC checks on all subsequent subframes, thereby resolving the contradiction between reliability and complexity.
2Measurement precision
If SD-RSRP measurement is performed on all n subframes, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent implements partial action by performing SD-RSRP measurements on a selected subset of subframes rather than all n subframes. Specifically, measurements are conducted on the kth subframe where successful decoding occurs and on subsequent n−k subframes where CRC is presumed successful, but skipping subframes before the kth successful decoding. This partial measurement approach maintains sufficient measurement precision while significantly reducing power consumption compared to measuring all subframes.
3Measurement precision
If decoding is performed on every PSDCH subframe, then measurement accuracy is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary action by performing full decoding only on the first PSDCH subframe (kth subframe) to validate CRC and establish measurement baseline. For subsequent subframes, the patent presumes successful CRC without performing full decoding, thereby maintaining measurement accuracy based on the preliminary validation while dramatically reducing processing time that would be required for complete decoding of every subframe.
Data Source
AI summary
A disclosure of the present specification provides a method for performing measurement on a physical sidelink discovery channel (PSDCH) including a discovery signal from an adjacent terminal. The method may comprise the steps of: when, among PSDCHs repeatedly transmitted from an adjacent terminal in n subframes, a PSDCH in a kth subframe is successfully decoded and thereby the cyclic redundancy check (CRC) thereof succeeds, regarding the CRC of PSDCHs in the subsequent n−k subframes as successful without decoding the same; and performing measurements in the kth subframe and the subsequent n−k subframes for which the CRC is regarded as successful.