Beam Switching Control for 5G NR Reliability
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Solution Overview
Problem
Beam misalignment issues occur during beam switching in 5G New Radio (NR) systems due to lost or erroneous ACK signals, leading to communication disruptions between base stations and user equipment.
Innovation Solution
A two-beam based retransmission scheduling method is implemented, where the base station schedules retransmissions using both the old and new beam directions until an ACK is received, ensuring accurate beam alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beam switching is implemented to improve communication performance, then system capacity and spectral efficiency are improved, but beam misalignment occurs when ACK signals are lost
Solution Approach 1:
The base station transmits the same beam switching indication multiple times before the UE is expected to acknowledge it. This preliminary repetition ensures that even if the UE misses one indication due to beam misalignment, it can still receive the switching command through another transmission, thereby preventing communication disruption while maintaining the benefits of beam switching.
Solution Approach 2:
The system uses ACK/NACK feedback from the UE to confirm successful reception of beam switching indications. When the base station does not receive an ACK or receives a NACK, it understands that the beam switching indication was not properly received and transmits additional indications, thus using feedback to maintain reliable beam alignment during dynamic beam switching operations.
2Loss of information
If beam switching indication is transmitted only once, then signaling overhead is reduced, but beam misalignment occurs when ACK is lost
Solution Approach 1:
Instead of transmitting the beam switching indication only once, the base station proactively transmits it multiple times in advance before the UE is expected to send an ACK. This preliminary repetition action ensures that at least one transmission will be successfully received even if beam misalignment occurs, thereby maintaining reliable beam alignment without requiring excessive redundant transmissions.
Solution Approach 2:
The system transmits beam switching indications more times than the minimum single transmission would suggest, but not excessively so. This partial excess action - transmitting 2-3 times instead of once - provides sufficient reliability margin to handle ACK loss scenarios while keeping signaling overhead manageable, achieving an optimal balance between reliability and efficiency.
3Reliability
If multiple beam switching indications are transmitted, then beam alignment reliability is improved, but signaling overhead increases
Solution Approach 1:
The base station transmits beam switching indications a limited number of times (2-3 repetitions) rather than continuously or excessively. This partial excess action provides sufficient reliability to handle ACK loss scenarios while preventing signaling overhead from becoming excessive, achieving an optimal balance between beam alignment reliability and signaling efficiency.
Solution Approach 2:
The system uses feedback mechanisms where the UE sends ACK/NACK to confirm receipt of beam switching indications. When the base station receives an ACK, it stops further repetitions; when no ACK or NACK is received, it continues transmitting additional indications. This feedback-driven approach ensures reliable beam alignment while minimizing unnecessary signaling overhead by stopping transmissions once success is confirmed.
Data Source
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AI summary
This disclosure relates to a beamforming controller for a beamforming transmitter device, the beamforming controller comprising a control element configured to: activate a first configuration state of a plurality of configuration states for a control channel, each configuration state indicating a beam direction of the control channel; control a beam switching of the control channel from the first configuration state to a second configuration state based on a beam direction of the control channel according to the first configuration state; and retransmit signaling of the beam switching based on a beam direction of the control channel according to both the first and the second configuration state if an acknowledgement to the beam switching is null, not received, missing or received in error.