Timing Offset Adjustment for Diverse Satellite Receiver Groups
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Solution Overview
Problem
Timing misalignment issues in diverse satellite communication systems due to different propagation times between mobile stations and satellites lead to inter-symbol interference (ISI), which hampers link budget improvement and communication performance.
Innovation Solution
A method and system that adjust timing offsets between mobile stations and reallocate timing misalignments among diverse paths, using a 'virtual satellite' concept to synchronize transmissions and employ zoning and scheduling techniques to ensure signals arrive within the cyclic prefix, thereby addressing timing misalignment and improving link budget.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diversity techniques are used to improve link budget, then communication reliability is improved, but timing misalignment occurs due to different propagation times from multiple satellites
Solution Approach 1:
The patent segments the timing alignment problem by dividing receivers into multiple groups, where each group is assigned to a specific satellite. This segmentation allows each group to be timing-aligned with its designated satellite independently, resolving the timing misalignment issue while maintaining diversity benefits across different satellite groups.
Solution Approach 2:
The patent performs preliminary timing offset adjustments and receiver grouping before signal combination. By pre-aligning timing offsets for each receiver group relative to its assigned satellite and pre-assigning satellites to groups based on timing characteristics, the system eliminates timing misalignment before diversity combining occurs.
2Loss of energy
If multiple satellites are used for diversity, then link budget is improved, but inter-symbol interference occurs due to propagation time differences
Solution Approach 1:
The patent segments the diversity paths by assigning different satellites to different receiver groups. This ensures that signals from each satellite arrive at their designated receivers within the cyclic prefix window, preventing inter-symbol interference while still utilizing multiple satellites for diversity gain.
Solution Approach 2:
The patent introduces a base station as an intermediary that coordinates the timing offset adjustments and satellite assignments. The base station calculates and distributes timing offset values to receivers and manages the grouping assignments, mediating between the multiple satellites and receivers to eliminate ISI while maintaining diversity.
3Manufacturing precision
If timing offsets are adjusted for each receiver, then timing alignment is improved, but system complexity increases
Solution Approach 1:
The patent merges receivers into groups based on their timing characteristics and assigns each group to a specific satellite. This merging approach reduces the number of independent timing adjustments needed, as all receivers in a group share the same satellite assignment and can use similar timing offset strategies, thereby reducing system complexity while maintaining timing alignment.
Solution Approach 2:
The patent creates a universal grouping and satellite assignment framework that can be applied across the entire network. The base station implements a universal algorithm for calculating timing offsets and assigning satellites to groups, which simplifies the overall system management compared to individualized timing adjustments for each receiver.
Data Source
AI summary
A method and system for achieving a link budget improvement in a diverse OFDM radio system by addressing the timing misalignment issue that can occur due to the differences in propagation time in signals between mobile stations and Radio Access Nodes. Timing misalignment is shared or split between the primary path to a primary Radio Access Node and a diverse path to a diverse Radio Access Node. The relative timing offsets between mobile stations are adjusted, the mobile stations are grouped into zones using a variety of different grouping techniques, and the transmission for each mobile station is scheduled, using one or more of a variety of scheduling techniques.