Group Lead UE Beam Failure Recovery Request
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Solution Overview
Problem
In 5G NR systems operating at high frequencies, beam failures due to high pathloss are common, leading to inefficient beam failure recovery processes where each UE sends a BFRQ upon detecting a failure, resulting in increased communications overhead.
Innovation Solution
A method where a single UE, designated as the Group Lead UE (GLUE), represents a group of UEs and sends a beam failure recovery request (BFRQ) on behalf of the group, reducing the number of BFRQs transmitted and minimizing communications overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each UE sends a BFRQ upon detecting a beam failure, then the beam failure recovery is initiated for each UE, but the communications overhead increases significantly
Solution Approach 1:
Multiple UEs that experience beam failure are grouped together, and a single representative BFRQ is sent on behalf of the group. This merging approach consolidates multiple individual recovery requests into one collective request, reducing the total number of BFRQ transmissions while ensuring that the beam failure recovery function is still initiated for all affected UEs.
2Quantity of substance
If a single GLUE sends BFRQ on behalf of a group of UEs, then the communications overhead is reduced, but the complexity of group management and UE selection increases
Solution Approach 1:
UEs are pre-grouped and a Group Lead UE (GLUE) is predetermined based on specific criteria such as UE ID, pathloss, or channel quality. This preliminary organization is established before beam failure occurs, so that when failure detection happens, the grouping structure is already in place and no additional complex real-time decisions are needed. The GLUE selection criteria are predefined, simplifying the management overhead.
3Quantity of substance
If UEs are grouped for beam failure recovery, then the number of BFRQ transmissions is reduced, but the time required for group formation and identification may increase
Solution Approach 1:
The grouping of UEs and selection of GLUE is performed in advance based on stable parameters such as UE identifiers, pathloss measurements, or channel quality indicators. This preliminary grouping is established before beam failure occurs, eliminating the need for time-consuming group formation processes at the moment of failure. The network can maintain these groups dynamically updated based on current channel conditions.
Data Source
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AI summary
A method for operating a user equipment (UE) includes detecting a failure of a first link between the UE and an access node, and based thereon, detecting a second link between the UE and the access node, sending, to the access node, a beam failure recovery request (BFRQ) on one or more physical random access channel (PRACH) resources associated a third link conveying a reference signal, wherein the third link and the second link are quasi co-located (QCLed), wherein the BFRQ includes a group identifier associated with a UE group including the UE, and monitoring one or more PRACH response opportunities associated with the one or more PRACH resources for a beam failure recovery response (BFRP).