Cooperative Relay Network Power Optimization via Dynamic Selection
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Solution Overview
Problem
Conventional cooperative relay networks face challenges in minimizing energy consumption and managing outage due to deep channel fading, with existing solutions neglecting the cost of acquiring channel state information (CSI) and not optimizing relay selection based on both source-to-relay and relay-to-destination links.
Innovation Solution
A method for selecting a subset of relay nodes that involves acquiring CSI through feedback and training, with relay selection and outage criteria based on decoded data, and explicit modeling of CSI overhead to optimize total power consumption, allowing for constructive signal addition at the destination node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple relay nodes are selected to transmit data packets in parallel, then throughput and energy efficiency are improved, but the complexity of coordinating and managing relay nodes increases
Solution Approach 1:
The patent segments the relay nodes into two distinct sets: those that decode data from the source and those that forward decoded data to the destination. This segmentation simplifies coordination by dividing relay functions into independent stages, reducing the complexity of managing multiple relays while maintaining parallel throughput benefits.
Solution Approach 2:
The patent introduces an intermediary mechanism where relay nodes first decode data from the source before forwarding to the destination. This intermediary decoding stage acts as a mediator that simplifies the overall coordination process, allowing relays to operate independently in two stages rather than requiring complex real-time coordination across all relays simultaneously.
2Use of energy by moving object
If relay nodes cooperate to forward data packets, then energy consumption is reduced, but the overhead for acquiring channel state information increases
Solution Approach 1:
The patent performs preliminary actions by having relay nodes decode data from the source before forwarding to the destination. This preliminary decoding stage is performed once per packet and eliminates the need for continuous CSI acquisition during data transmission, reducing overhead while maintaining energy efficiency through cooperative relay operation.
Solution Approach 2:
Relay nodes utilize their own received data from the source to forward to the destination without requiring additional CSI feedback mechanisms. Each relay uses the data it successfully decoded to forward, making the system self-sufficient and eliminating the need for complex CSI acquisition overhead while maintaining energy efficiency.
3Ease of operation
If a single best relay is selected based on mean channel gains, then relay selection simplicity is improved, but outage probability increases due to deep channel fading
Solution Approach 1:
The patent dynamically adapts relay selection based on actual packet transmission success rather than static mean channel gains. Relays are selected and evaluated based on their actual performance in decoding and forwarding packets, allowing the system to respond to deep fading conditions in real-time while maintaining simple selection criteria. This dynamic approach reduces outage probability without complicating the selection process.
Data Source
AI summary
A method and system for communicating information in a cooperative relay network of wireless nodes. The wireless nodes including a source, a set of relays, and a destination. Channel state information for each channel between a particular relay of the set of relays and the destination is estimated. A subset of the relays is selected based on the channel state information. The channel state information is fed back to the subset of relays. The source node can then broadcasting data packets from the source to the subset of relays, and the subset of relays forward coherently the data packets from the subset of relays to the destination using beamforming based on the channel state information, while adjusting power to minimize a total energy consumption in the network.