Full-Duplex Relay Selective Transmission for Interference Control
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Solution Overview
Problem
Current Multiple-Access Relay Channel (MARC) and Multiple-Access Multiple Relay Channel (MAMRC) systems face challenges in improving transmission reliability and spectral efficiency, particularly in mobile networks where interference and error propagation are significant, leading to reduced coverage and increased energy consumption.
Innovation Solution
A full-duplex relay system that decodes and re-encodes messages from multiple sources, using network coding to create a spatially distributed code, and selectively transmits only error-free messages to the destination, optimizing channel usage and reducing interference by coordinating with the destination through a return channel to ensure correct decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex relay transmits and receives simultaneously on the same frequency band, then capacity increases, but interference and error propagation increase
Solution Approach 1:
The patent segments the relay operation into distinct phases: an uplink phase where the relay receives signals from sources, and a downlink phase where the relay transmits signals to the destination. This time-division approach prevents simultaneous transmission and reception on the same frequency band, eliminating self-interference while maintaining full-duplex capacity benefits through efficient phase coordination
Solution Approach 2:
The patent implements a return channel from the destination to the relay that provides feedback about decoding status. The relay uses this feedback to selectively transmit only those messages that were correctly decoded by the destination, thereby reducing error propagation and improving transmission reliability while maintaining high capacity utilization
2Productivity
If relay transmits all decoded messages, then spectral efficiency improves, but energy consumption increases
Solution Approach 1:
The patent applies partial action by having the relay transmit only a subset of decoded messages - specifically, only those messages that the destination has not yet correctly decoded. This selective transmission approach maintains spectral efficiency by utilizing the return channel feedback to identify which messages need retransmission, while reducing energy consumption by avoiding redundant transmissions of already correctly received messages
3Reliability
If relay uses network coding with multiple sources, then diversity gain increases, but decoding complexity increases
Solution Approach 1:
The patent applies preliminary action by having the relay perform network coding and encode multiple source messages into a single coded transmission before sending to the destination. This pre-encoding approach creates diversity gain by combining information from multiple sources in advance, while the destination handles the decoding complexity using the returned feedback information, thereby distributing the computational burden
Data Source
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AI summary
The invention relates to a full-duplex relay intended for a telecommunication system comprising several sources, at least the relay and a recipient, implementing a relay method. The relay (R) comprises: - a decoder (DDU) for estimating a message for each source, from successive received blocks transmitted during a current interval t of transmission by a source S ε {S 1 , S 2 , S M ) corresponding to a code word c s, t comprising B s blocks/ c (1) / S, t, , c (2) / S, t ,c (b) / S, t , c B s ) / S, t encoding a message u S, t of K bits, a decision module (DU) for deciding which source messages u S,t were decoded without error from the estimated messages, upon each estimation of a message following a received block, a network encoder (ETU) for encoding a selection of the messages decoded without error and a transmitter (ETU) for transmitting a signal representative of the network encoded messages to the destination and a control signal indicating the selected messages. The decision module (DU) selects the messages decoded without any error at the input of the network encoder (ETU) by only considering a return path (fdb) coming from the destination indicating a correct or incorrect decoding of one or several messages from the sources. After each reception of a block by the relay (c (b) / S,t ) the decision module (DU) prevents the emission by the transmitter for a period of time necessary to receive and decode the return path (fdb).