Sidelink Beam Failure Recovery Using Reference Signals
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Solution Overview
Problem
In vehicle-to-everything (V2X) sidelink communications, beam misalignment due to movement or environmental changes leads to signal-to-noise ratio drops, necessitating efficient beam failure recovery mechanisms to maintain communication efficiency.
Innovation Solution
A method where a first sidelink user equipment measures multiple reference signals using multiple receive beams, selects a suitable reference signal based on received signal strength, and notifies the second sidelink user equipment to re-establish communication using the corresponding beam, employing either sidelink contention free random access or contention-based random access techniques for beam failure recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming is used to maintain signal quality in V2X sidelink communications, then communication reliability is improved, but system complexity increases due to the need for beam management and failure recovery mechanisms
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple candidate beams and their corresponding reference signals before beam failure occurs. When beam failure is detected, the UE can immediately switch to a pre-prepared candidate beam without requiring complex real-time beam searching, thus maintaining communication reliability while reducing the complexity of beam management operations.
Solution Approach 2:
The patent implements self-service through autonomous beam failure detection and recovery mechanisms at the UE level. Each UE independently monitors beam quality metrics, detects failures, selects alternative beams from pre-configured candidates, and executes recovery without requiring complex network coordination, thereby improving reliability while keeping system complexity manageable.
2Speed
If multiple reference signals are transmitted periodically for beam failure recovery, then beam alignment recovery speed is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by transmitting reference signals at predetermined intervals rather than continuously. This periodic transmission provides sufficient opportunities for beam failure detection and recovery while significantly reducing energy consumption compared to continuous transmission. The periodic intervals are optimized to balance recovery speed requirements with energy efficiency.
Solution Approach 2:
The patent uses partial action by transmitting reference signals only when necessary for beam failure recovery rather than continuously. The system transmits a sufficient number of reference signals at strategic intervals to enable reliable beam alignment recovery, avoiding excessive transmissions that would waste energy, thus achieving an optimal balance between recovery speed and energy consumption.
3Stability of the object's composition
If beam failure recovery mechanisms are implemented in sidelink communications, then communication stability is improved, but latency increases due to additional signaling and random access procedures
Solution Approach 1:
The patent reduces latency by performing preliminary configuration of multiple candidate beams and their associated random access resources before beam failure occurs. When failure is detected, the UE can immediately activate a pre-selected candidate beam and use pre-configured random access resources, eliminating the need for time-consuming beam searching and resource allocation procedures during recovery, thus maintaining stability while minimizing latency.
Solution Approach 2:
The patent applies skipping by allowing the UE to bypass standard beam selection and resource allocation procedures during beam failure recovery. By using pre-configured candidate beams and associated random access resources, the system rushes through the recovery process directly to re-establish communication, significantly reducing the time penalty compared to standard recovery procedures while maintaining communication stability.
Data Source
AI summary
A method of wireless communication by a first sidelink UE measures multiple reference signals periodically transmitted by a second sidelink UE using multiple receive beams corresponding to reference signals in response to a beam failure declared by the first UE. The method also selects one of the reference signals that satisfies a condition. The method further includes notifying the second sidelink UE of the selected reference signal using a beam corresponding to the selected reference signal. Another method of wireless communications by a first sidelink UE includes periodically transmitting, to a second sidelink UE, multiple beam failure recovery (BFR) reference signals across multiple transmit beams. The method also includes receiving, from the second sidelink UE, an indication of a selected beam for communications between the first sidelink UE and the second sidelink UE. The method notifies the second sidelink UE of successful beam failure recovery.