User Cooperative Communication Using Erroneous Relay Packets
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Solution Overview
Problem
Existing cooperative communication methods either lose soft information or fail to regenerate signals, lacking the advantages of both amplify-and-forward and decode-and-forward schemes, especially in scenarios with poor interlink channel quality.
Innovation Solution
A user cooperative communication method that utilizes erroneously decoded packets at relay nodes as side information to assist decoding at the destination node, employing different operation modes based on channel conditions to combine and decode packets effectively, including the use of pre-determined a priori log-likelihood ratios to improve decoding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If amplify-and-forward scheme is employed, then soft information is kept, but signal regeneration capability is lost
Solution Approach 1:
The patent merges the advantages of amplify-and-forward (keeping soft information) and decode-and-forward (signal regeneration) by combining the received signal with the re-encoded relay packet to form a combined signal for decoding. This allows the system to simultaneously preserve soft information and achieve signal regeneration through iterative decoding processes.
2Reliability
If decode-and-forward scheme is implemented, then signal regeneration is achieved, but soft information is lost
Solution Approach 1:
The patent applies preliminary action by performing hard decoding at the relay node to generate a re-encoded packet before forwarding, while simultaneously preserving the original soft information. The destination node then uses both the re-encoded packet and the original soft information in a combined decoding process, effectively recovering signal regeneration capability without completely losing soft information.
3Reliability
If cooperative communication is used to achieve transmit diversity, then performance is enhanced, but system complexity increases
Solution Approach 1:
The patent segments the cooperative communication process into distinct phases: the relay node performs hard decoding and re-encoding to generate a simplified relay packet, while the destination node handles the complex combined signal decoding. This segmentation distributes computational complexity across different nodes, reducing the burden on any single device while maintaining transmit diversity benefits.
4Measurement precision
If multiple packets are combined and decoded, then decoding accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent applies local quality by using different decoding strategies for different signal components: the relay packet is hard-decoded and re-encoded to provide a clean reference signal, while the direct received signal is combined with this reference and decoded with a priori information. This localized application of different processing qualities optimizes decoding accuracy while managing complexity by assigning different processing intensities to different signal paths.
Data Source
AI summary
A wireless network system and corresponding methodologies that operate in a user cooperative communication system are provided. In operation, the system either combines packets transmitted from a direct channel with packets transmitted from and a relay channel, or uses erroneously relayed packets to assist decoding a direct packet.