Bandwidth Part Misalignment Prevention in 5G Beam Failure Recovery
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Solution Overview
Problem
In wireless communication systems, particularly in next-generation networks like 5G, there is a challenge in preventing bandwidth part misalignment between user equipment (UE) and the network, which can lead to beam failure and disrupt communication services.
Innovation Solution
The method involves transmitting a Scheduling Request (SR) on a first uplink bandwidth part (BWP), receiving a response on a corresponding downlink BWP, detecting beam failure, and sending a beam failure recovery (BFR) request on the same uplink BWP, followed by receiving control signaling on a second downlink BWP associated with the first uplink BWP to recover from beam failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE continues to monitor the first downlink BWP after beam failure detection, then the UE maintains continuity in monitoring, but the beam failure cannot be recovered and communication is disrupted
Solution Approach 1:
The network pre-configures multiple downlink BWPs associated with the uplink BWP before beam failure occurs. When beam failure is detected, the UE can immediately switch to a pre-configured second downlink BWP to receive control signaling for beam recovery, avoiding the need for complex real-time BWP configuration and switching during failure recovery.
2Reliability
If the network switches downlink BWP dynamically to respond to beam failure, then beam recovery can be achieved, but BWP misalignment may occur between UE and network
Solution Approach 1:
The UE sends a beam failure recovery request on the uplink BWP, and the network responds with control signaling on the second downlink BWP. This feedback mechanism ensures that both UE and network agree on the BWP switching, maintaining alignment and preventing information loss about which BWP should be active.
3Reliability
If the UE switches to a second downlink BWP for beam recovery, then beam failure can be recovered, but the switching process may cause service disruption
Solution Approach 1:
Multiple downlink BWPs are pre-configured and associated with the uplink BWP before beam failure occurs. When beam failure is detected, the UE can immediately switch to the pre-configured second downlink BWP without waiting for network configuration, significantly reducing the time for beam recovery and minimizing service disruption.
Data Source
AI summary
A method and apparatus are disclosed from the perspective of a UE (User Equipment). In one embodiment, the method includes transmitting a Scheduling Request (SR) on a first uplink bandwidth part (BWP). The method further includes receiving a response for the SR on a first downlink BWP. The method also includes detecting a beam failure when using the first uplink BWP and the first downlink BWP. In addition, the method includes transmitting a beam failure recovery (BFR) request to a network node on the first uplink BWP. Furthermore, the method includes receiving a control signalling on a second downlink BWP from the network node after transmitting the BFR request, wherein the control signalling is a response for the BFR request and the second downlink BWP is associated with the first uplink BWP.