Satellite Channel Quality Feedback for Inter-Beam Handovers
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Solution Overview
Problem
In satellite communication systems, inter-beam handovers lead to significant changes in channel conditions due to the quick movement of non-geosynchronous satellites, making pre-handover modulation and coding schemes suboptimal, resulting in reduced throughput and quality of communications.
Innovation Solution
A user terminal measures the channel quality of the target beam during an inter-beam handover and sends this information to the network controller via reverse-link communication, allowing the controller to dynamically adjust the modulation and coding scheme post-handover to optimize communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an MCS optimized for pre-handover channel conditions is used, then communication quality is maintained during stable beam operation, but throughput deteriorates after inter-beam handover due to suboptimal MCS selection
Solution Approach 1:
The user terminal measures channel quality of the target beam and feeds back this information to the network controller. The controller uses this feedback to dynamically select an appropriate MCS for post-handover communications, ensuring optimal throughput while maintaining communication quality.
Solution Approach 2:
The user terminal performs channel quality measurement of the target beam before the handover is complete. This preliminary measurement allows the network controller to prepare and apply the optimal MCS immediately after handover, preventing throughput deterioration.
2Measurement precision
If channel quality measurement is performed after handover completion, then accurate post-handover channel conditions are captured, but timing delay reduces the effectiveness of MCS adjustment
Solution Approach 1:
The channel quality measurement is performed in advance during the handover process itself, specifically measuring the target beam's channel quality before the handover completes. This timing allows the network controller to have the measurement results ready immediately when needed for MCS selection, eliminating delays.
Solution Approach 2:
The measurement timing is dynamically adjusted to occur during the handover transition period rather than after completion. This dynamic timing strategy captures accurate post-handover channel conditions while minimizing the delay before MCS adjustment can take effect.
Data Source
AI summary
A method and apparatus for operating a user terminal in a satellite communication system during inter-beam handovers. In some aspects, the user terminal may determine an occurrence of an inter-beam handover for switching communication with a network controller of the satellite communication system from a first beam to a second beam. The user terminal measures a channel quality of the second beam based at least in part on the occurrence of the inter-beam handover, and sends the channel quality measurement to the controller via a reverse-link communication.