Opportunistic Relay Coordination in Wireless Networks
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Solution Overview
Problem
Current cooperative relaying systems in wireless communication networks face inefficiencies due to reliance on pre-selected relays, requiring additional coordination, synchronization, and increased diversity gain, which can lead to performance degradation and increased communication overhead, especially in ad-hoc networks and military communication systems.
Innovation Solution
A cooperative, opportunistic relaying system that allows for transmission in a common channel and time interval without relay coordination, utilizing a receiver structure with blind channel equalization techniques, such as the Generalized Viterbi Algorithm, to process signals from unsynchronized relays, enabling maximum diversity gain without precise synchronization or knowledge of relay numbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pre-selected relays are used for cooperative relaying, then relay selection can be performed in advance, but diversity gain decreases and system becomes dependent on a single relay
Solution Approach 1:
The patent transitions from static pre-selected relays to dynamic opportunistic relaying where any node receiving adequate signal quality can become a relay. This dynamic selection allows the system to adapt to changing channel conditions and continuously exploit the best available relays, maximizing diversity gain while maintaining low latency.
Solution Approach 2:
The patent changes the selection criterion parameter from fixed pre-selection to real-time signal quality measurement. By using post-selection based on actual received signal quality metrics, the system identifies relays with strong channels both to source and destination, thereby improving diversity gain without requiring advance coordination.
2Reliability
If multiple relays transmit in different channels, then diversity gain increases, but communication efficiency decreases due to increased time and bandwidth usage
Solution Approach 1:
The patent merges multiple relay transmissions into a common channel and time interval instead of allocating separate channels. By combining signals from multiple opportunistic relays in the same resource block, the system achieves diversity gain while improving communication efficiency and reducing overall resource consumption.
Solution Approach 2:
The patent enables continuous transmission from multiple relays in the same time interval without waiting for channel allocation turns. This continuous parallel transmission in shared resources maximizes the utilization of available relays and maintains high communication efficiency while achieving diversity through simultaneous signal reception.
3Productivity
If distributed space-time coding or beamforming is used for common channel transmission, then relays can transmit simultaneously, but precise synchronization and coordination are required
Solution Approach 1:
The patent enables relays to autonomously decide whether to participate in relaying based on their own signal quality measurements without requiring coordination with other relays or the source. Each relay independently evaluates channel conditions and self-selects to become a relay, eliminating the need for complex synchronization and coordination mechanisms.
Solution Approach 2:
The patent extracts the coordination requirement from the relaying process by allowing relays to operate independently. By removing the need for inter-nodal coordination messages and synchronization protocols, the system achieves simple opportunistic relaying where relays autonomously transmit in common resources based on local channel conditions.
4Device complexity
If relay selection is updated at intervals based on previous success rates, then coordination is reduced, but adaptability to continuous channel changes decreases
Solution Approach 1:
The patent implements continuous periodic evaluation of channel conditions at each transmission opportunity rather than interval-based updates. Every time the source transmits, receiving nodes independently assess signal quality and can become relays, providing continuous adaptation to channel changes without requiring coordination overhead for updates.
Data Source
AI summary
The present invention relates to a cooperative relaying system (1) and method (100) in which many different units in the network can be used in a common channel and time interval by way of repetition without requiring additional relay coordination in cases where the connection between the source and the destination is insufficient in wireless communication networks. The inventive system (1) and method (100) increases the probability of the transmission of the source data with the maximum diversity gain requiring no coordination thanks to determining the relays (3) without pre-selection and keeping the amount of band spent to a minimum.