Wireless Relay Path Selection Using Capacity-Delay Metrics
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Solution Overview
Problem
Existing wireless communication systems with relays lack a method to effectively select paths for data packets that consider service parameters, such as delay sensitivity and Quality of Service (QoS) requirements, leading to potential performance issues due to incorrect path selection.
Innovation Solution
A method for selecting paths in wireless communication systems that takes into account service requirements, including delay sensitivity and QoS, allowing for dynamic, semi-static, or static path selection based on capacity, throughput, and delay performance, enabling different data streams to use optimal paths according to their needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If path selection is based only on capacity impact, then system capacity is improved, but delay performance deteriorates
Solution Approach 1:
The patent introduces a composite path selection metric that changes the selection parameter from pure capacity-based to a multi-parameter metric incorporating both capacity and delay. The metric is defined as: metric = capacity_gain * weight_capacity + delay_penalty * weight_delay, where weights can be adjusted based on service requirements. This allows the system to balance capacity improvement with delay constraints.
Solution Approach 2:
The path selection mechanism is made dynamic by allowing the metric weights to be adjusted based on service type and current network conditions. For delay-sensitive services, the delay penalty weight is increased, while for capacity-sensitive services, the capacity gain weight is emphasized. This dynamic adjustment enables the system to adapt to different operational requirements.
2Productivity
If relay paths are used to increase capacity, then throughput is improved, but service quality for delay-sensitive applications deteriorates
Solution Approach 1:
The patent applies different path selection criteria to different data streams based on their service requirements. Delay-sensitive traffic (e.g., voice, real-time video) is routed through paths selected with high delay penalty weights, while delay-tolerant traffic (e.g., file transfers, email) can utilize paths optimized for capacity. This local differentiation ensures each service receives appropriate quality of service.
Solution Approach 2:
The patent segments the network traffic into different service classes and applies distinct path selection metrics to each segment. By dividing traffic into delay-sensitive and delay-tolerant categories, the system can optimize paths independently for each segment, ensuring that throughput improvements do not compromise service quality for critical applications.
3Device complexity
If a single path selection metric is used, then system simplicity is maintained, but adaptability to different service requirements deteriorates
Solution Approach 1:
The patent creates a universal path selection framework that can handle multiple service types through a single metric formulation. The composite metric structure (capacity_gain * weight_capacity + delay_penalty * weight_delay) serves as a multi-functional tool that adapts to different service requirements by adjusting weights, rather than requiring separate metrics for each service type.
Solution Approach 2:
The system maintains simplicity by changing parameters (weights) rather than changing the fundamental metric structure. The same metric formula is used for all services, but the weight parameters are adjusted based on service requirements, allowing adaptability without increasing structural complexity.
Data Source
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AI summary
A method selects a path for forwarding a data packet in a wireless communication system. A system capacity versus delay impact curve is calculated for a direct path to mobile station. The direct path has a capacity cost based on communication quality of a direct link between a base station and the mobile station. This curve is shifted by a predetermined time corresponding to an additional delay over a relay path to produce a projected capacity curve for the relay path having a second capacity cost determined according to a combined measure of signal quality of multiple links in the relay path. The second capacity cost is multiplied by a capacity cost ratio to produce a relay capacity curve. The direct path or the relay path is selected based on a comparison of the system capacity versus delay impact curve and the relay capacity curve according to a QoS requirement.