Joint-User Channel Coding for Equal-SNR Wireless Cooperation
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Solution Overview
Problem
Conventional coded cooperation in wireless communication systems relies solely on spatial diversity gain, which disappears when cooperating users operate at the same receive signal-to-noise ratio, limiting additional performance benefits beyond spatial diversity.
Innovation Solution
Implementing cooperative concatenated coding that allows users to encode and transmit joint messages, utilizing a more powerful joint-user channel code and interleaver gain, enabling performance improvements even when users have equal receive SNR and supporting unequal message sizes and multiple cooperating users with reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coded cooperation is used to achieve spatial diversity gain, then error performance is improved when users have different receive SNR ratios, but the coding gain disappears when users operate at the same receive SNR ratio
Solution Approach 1:
The patent changes the fundamental parameter of the cooperation strategy from relying on SNR differences between users to using joint encoding of multiple users' messages. By transforming the cooperation mechanism from individual message relaying to joint message encoding, the system achieves coding gains that are independent of SNR ratio differences, resolving the contradiction between reliability improvement and adaptability to equal SNR conditions.
Solution Approach 2:
The joint-user channel code serves multiple functions simultaneously: it provides error protection for all cooperating users' messages, creates interleaver gain through joint encoding, and achieves coding benefits regardless of individual user SNR conditions. This multi-functional approach allows the same coding mechanism to deliver performance improvements in both equal-SNR and unequal-SNR scenarios.
2Reliability
If joint-user channel codes are used to achieve coding benefits, then interleaver gain is increased, but system complexity increases
Solution Approach 1:
The patent segments the joint encoding process into manageable components: individual user messages are encoded separately first, then combined through joint-user channel coding with interleaving. This segmentation allows the complex joint encoding to be broken down into simpler sequential operations, reducing implementation complexity while maintaining the interleaver gain benefits.
Solution Approach 2:
The system performs preliminary individual encoding of each user's message before joint-user channel coding. This preliminary action prepares the messages in a standardized format, simplifying the subsequent joint encoding process and reducing the complexity of the overall system by pre-processing inputs before the complex joint operation.
3Reliability
If cooperative strategies are implemented to achieve spatial diversity, then system performance is improved, but bandwidth efficiency is reduced
Solution Approach 1:
The patent merges multiple users' messages into a single joint-encoded transmission. By combining the information from multiple users into one coordinated transmission using joint-user channel codes, the system achieves spatial diversity benefits while using the channel more efficiently than separate individual transmissions would require.
Data Source
AI summary
Cooperative concatenated coding techniques are provided for wireless communications between at least two users and a base station. A network system employing cooperative concatenated coding includes cooperating user devices each configured to encode and transmit at least a potion of a joint message. The joint message includes at least a potion of a first message from a first cooperating user device and at least a potion of a second message from a second cooperating user device. An embodiment includes encoding a first message from a first cooperating user, receiving a second message from a second cooperating user and decoding the second message. The methodology also includes re-encoding at least a potion of the decoded message with at least a potion of the first message to form a combined message, and then transmitting at least a potion of the combined message.