RIS Beam Failure Recovery Using Direct and Reflective Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing 5G NR systems face challenges in effectively recovering from beam failure during initial access due to the limited number of candidate beams, leading to unsuccessful beam failure recovery and radio link failure, which is a critical issue for low-latency communications.
Innovation Solution
A method utilizing a reconfigurable intelligent surface (RIS) to expand the candidate beam set by including both direct and reflective paths, using measured RSRP values to select beams, and employing K-means clustering to optimize beam selection for beam failure recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If beam failure recovery is attempted using a limited number of candidate beams, then the device complexity is reduced, but the reliability of beam failure recovery deteriorates
Solution Approach 1:
The patent introduces a new dimension to beam failure recovery by incorporating RIS-assisted reflective paths in addition to direct paths. This expands the candidate beam set from limited direct beams to include both direct and reflective beams, effectively adding a spatial dimension (reflection dimension) to the beam selection process, thereby increasing recovery reliability without significantly increasing device complexity
Solution Approach 2:
The RIS acts as an intermediary element that creates alternative reflective paths between the base station and user equipment. By introducing this intermediary, the system can recover from beam failure even when direct paths are blocked or degraded, as the RIS provides additional candidate beams through reflection, thus improving reliability without requiring the UE to handle all path computations directly
2Ease of operation
If only direct path beams are used for beam failure recovery, then the ease of operation is improved, but the adaptability to different communication paths deteriorates
Solution Approach 1:
The patent makes the beam failure recovery mechanism universal by enabling it to handle both direct paths and reflective paths through RIS. The same beam failure recovery procedure can operate with either direct beams or reflective beams depending on channel conditions, making the system adaptable to different communication scenarios without requiring separate mechanisms for each path type
Solution Approach 2:
The system dynamically selects between direct and reflective paths based on measured RSRP values. The beam selection is not fixed but adapts in real-time according to channel conditions, allowing the system to switch between direct and RIS-assisted paths as needed, thereby improving adaptability while maintaining operational simplicity through automated measurement and selection
Data Source
AI summary
Disclosed is a beam failure recovery method of a base station in a wireless communication system using an RIS. The beam failure recovery method may include configuring a candidate beam set, based on a measured RSRP value in beam sweeping using an antenna, establishing a communication link with a UE through a main beam having the measured RSRP value exceeding a predetermined threshold in the configured candidate beam set, selecting a beam, based on the measured RSRP value, from an SSB to which the main beam belongs and an SSB to which the main beam does not belong when beam failure occurs in the established communication link, and recovering the beam failure with the UE through the selected beam. Accordingly, beam failure recovery may be more effectively performed.