OMAMRC Transmission with Slow-Link Adaptation
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Solution Overview
Problem
Existing communication systems with relaying techniques face challenges in maximizing sum throughput in multi-user networks with asymmetric bit rates, especially under slow fading and white Gaussian noise conditions, where the destination lacks knowledge of instantaneous links between sources and relays.
Innovation Solution
A method for transmitting messages in an OMAMRC system with selective decode and forward relaying, where the destination determines initial bit rates based on average SNR, and cooperative retransmissions are used to maximize sum bit rate, allowing sources and relays to act as relays, and incorporating incremental redundancy coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the destination uses limited feedback to control relay transmissions, then spectral efficiency is improved, but the destination cannot know the quality of source-relay and relay-relay links
Solution Approach 1:
The patent introduces control channels as intermediary communication paths that carry feedback information from the destination to sources and relays. These control channels enable the destination to convey decoding results and relay selection decisions without requiring direct knowledge of all link qualities, thus resolving the information asymmetry while maintaining spectral efficiency.
Solution Approach 2:
The system implements feedback mechanisms where the destination sends limited feedback signals to sources and relays indicating decoding status and relay selection. This feedback enables adaptive transmission without requiring the destination to know instantaneous link qualities, allowing spectral efficiency improvement while managing information constraints.
2Reliability
If relays transmit redundant signals based on incremental encoding, then reliability is improved, but control information overhead increases
Solution Approach 1:
The patent applies incremental redundancy coding where relays transmit only the necessary amount of redundant information based on decoding requirements. Instead of always transmitting full redundancy, the system transmits partial redundancy proportional to what is needed to achieve reliable decoding, thus improving reliability while minimizing control information overhead.
Solution Approach 2:
The system dynamically adjusts the amount of redundant information transmitted by relays based on real-time decoding needs and channel conditions. The incremental encoding rate and redundancy level are adapted dynamically rather than being fixed, allowing reliability improvement without excessive control overhead.
Data Source
Figure 1~3
AI summary
The present invention relates to a method for transmitting successive messages forming a frame in a telecommunication system with M sources (S 1 ,..., s M ), L relays and a destination, M > 1, L ≥ 1 according to an orthogonal multiple access scheme of the transmission channel between the M sources and the L relays with a maximum number of M + T max time intervals per transmitted frame, including M intervals allocated during a first phase to the successive transmission of the M sources and T max cooperative transmission intervals allocated during a second phase to one or more nodes taken from among the sources and the relays according to a determined selection. The method comprises: an initial link adaptation phase involving determining an initial bit rate for each source by the destination based on a mean SNR of each of the links of the system and involving transmitting, to each source of this initial bit rate, for each frame from among a plurality of frames, the successive transmissions of the messages of the M sources during the M intervals of the first phase with, respectively, modulation and encoding schemes determined on the basis of the initial bit rates, the link adaptation is of the slow type and involves maximising the total bit rate of all the stressed sources of a target mean BLER εcom at the end of T max ≥ X ≥ 1 cooperative transmissions.