Radio Link Monitoring Thresholds Using SSB BLER in 5G NR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The complexity of defining radio link monitoring (RLM) performance requirements and the lack of flexibility in supporting different systems, particularly in 5G new radio (NR) systems, where the existing LTE RLM methods are not applicable due to the absence of a physical downlink control channel (PDCCH) in synchronization signals (SS)/physical broadcast channel (PBCH) blocks (SSB).
Innovation Solution
A radio link monitoring method that determines the in-sync threshold based on a preset parameter value or block error rate (BLER) of the synchronization signal (SS)/physical broadcast channel (PBCH) block (SSB) in the NR system, allowing for flexible adjustment of thresholds and simultaneous RLM and NR PDCCH performance testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LTE RLM method based on hypothetical PDCCH is used in 5G NR, then the mapping from PDCCH BLER to in-sync/out-of-sync thresholds can be implemented, but the system complexity increases and flexibility is reduced due to the absence of actual PDCCH in SSB
Solution Approach 1:
The patent extracts the essential function of RLM from the PDCCH-based method and applies it directly to SSB. Instead of maintaining the complex hypothetical PDCCH mapping mechanism, the invention directly uses SSB signal quality metrics (RSRP, SINR) to determine in-sync/out-of-sync status, eliminating the need for hypothetical channel construction while preserving the core RLM functionality.
Solution Approach 2:
The patent makes the SSB serve multiple functions: it acts as both the synchronization signal and the reference for radio link monitoring. By configuring the SSB with both synchronization functions and RLM reference functions, the system eliminates the need for separate hypothetical PDCCH structures, thereby reducing complexity while maintaining reliability.
2Measurement precision
If the hypothetical PDCCH method is used for RLM in NR, then threshold mapping can be achieved, but the ability to simultaneously test RLM and NR PDCCH performance is lost
Solution Approach 1:
The patent merges the RLM testing function with the SSB signal structure. By using the actual SSB transmission and reception process for both synchronization and RLM threshold determination, the system enables simultaneous testing of both SSB performance and RLM functionality without requiring separate hypothetical PDCCH test scenarios.
3Ease of manufacture
If fixed threshold values are used for RLM in NR, then implementation is simplified, but the ability to adjust thresholds for different specific systems is reduced
Solution Approach 1:
The patent introduces dynamic threshold configuration where the network can independently adjust in-sync and out-of-sync thresholds based on specific system requirements, service types, and channel conditions. This dynamic configuration capability allows the system to adapt to different scenarios (e.g., ultra-reliable low-latency communication, enhanced mobile broadband) while maintaining a unified RLM framework.
Data Source
AI summary
Disclosed in the present application are a radio link monitoring method and apparatus, the method comprising: when a UE performs radio link monitoring, the UE monitors a downlink signal of a primary serving cell to obtain monitoring results; and the UE compares the monitoring results with an required synchronization threshold to determine whether the UE is in a synchronized state; the synchronization threshold is determined on the basis of preset parameters. The present invention solves the problems in the prior art of the complexity of defining RLM performance requirements, and being unable to provide the needed flexibility for supporting different specific systems by means of adjusting thresholds.