Relay Scheduling via Weighted Bipartite Graph Matching
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Solution Overview
Problem
Existing relay-assisted wireless networks face challenges in optimizing throughput and reducing feedback overhead, particularly in two-hop networks, where prior art systems fail to exploit spatial reuse and effectively manage feedback on relay links, leading to bottlenecks.
Innovation Solution
A scheduling system that leverages diversity and spatial reuse by using a weighted bipartite graph for matching methods, incorporating feedback reduction mechanisms to consolidate and prioritize user feedback, and generating transmission schedules that account for traffic loads and fairness across relay and access channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feedback overhead is increased to exploit spatial reuse and diversity gains, then network throughput is improved, but relay link capacity is reduced due to bottleneck constraints
Solution Approach 1:
The patent segments the feedback overhead into two parts: essential feedback that must be transmitted to maintain spatial reuse and diversity gains, and non-essential feedback that can be reduced or eliminated. This segmentation allows the system to maintain necessary network performance while reducing the total feedback overhead on relay links.
Solution Approach 2:
The patent extracts and identifies the minimum necessary feedback requirements for exploiting spatial reuse and diversity gains. By taking out only the essential feedback elements needed for network optimization, the system reduces overall feedback overhead while maintaining throughput performance.
2Productivity
If relay stations are added to improve throughput and coverage, then network capacity is enhanced, but feedback overhead on relay links increases creating bottlenecks
Solution Approach 1:
The patent performs preliminary analysis to determine the minimum feedback requirements before implementing feedback transmission. By pre-identifying which feedback is essential for maintaining network capacity with multiple relay stations, the system avoids unnecessary feedback overhead and simplifies management complexity.
Solution Approach 2:
The patent changes the feedback parameter structure by identifying and transmitting only the critical feedback parameters needed for spatial reuse and diversity exploitation. This parameter optimization reduces feedback overhead while maintaining enhanced network capacity provided by multiple relay stations.
3Reliability
If multiple channels are used to provide diversity, then network reliability is improved, but feedback overhead becomes especially high on relay links
Solution Approach 1:
The patent uses copying by having relay stations forward feedback information from multiple channels in a consolidated manner rather than transmitting separate feedback for each channel. This copying approach maintains diversity reliability while significantly reducing the total feedback overhead on relay links.
Solution Approach 2:
The patent merges feedback from multiple channels into a consolidated feedback structure that maintains the diversity information needed for reliable communication. By combining feedback elements across channels, the system preserves network reliability while reducing the overall feedback overhead on constrained relay links.
Data Source
AI summary
A scheduling system and method for use with relay-assisted wireless networks includes accessing feedback from mobile stations in a network and arranging users associated with a relay station in a list in accordance with marginal utilities. A determination of whether the users in the list can be eliminated from feedback overhead by testing conditions for feedback reduction is made. A diversity schedule is generated by employing a weighted bipartite graph with relay channels and access channels and performing a matching method. A transmission schedule is generated for channel usage in accordance with multi-user and channel diversity for mobile users and spatial reuse of channels across relay and access hops by incorporating rate feedback and interference for the mobile stations and the relay stations based upon the matching method applied to a new weighted graph which accounts for traffic loads and fairness as well.