Basic Performance Analysis of DF (Decode-and-Forward) Cooperative Communications

This MATLAB simulation analyzes the basic performance of Decode-and-Forward (DF) cooperative communication systems. The implementation employs a three-node configuration (Source-Relay-Destination) with Maximum Ratio Combining (MRC) technique at the receiving terminal. The simulation code models signal transmission through dual paths: direct SD link and relayed SR-D link, where the relay node decodes and retransmits received signals. Under fixed DF protocol constraints, system performance becomes limited by potential decoding errors in the SR channel, particularly manifesting as inability to achieve effective diversity gain in high Signal-to-Noise Ratio (SNR) scenarios. The implementation includes distance parameter configuration between S and R nodes, with performance metrics evaluated through Bit Error Rate (BER) versus SNR curves. When the SR distance is sufficiently reduced, the simulation demonstrates potential diversity gain improvement through comparative analysis of different distance parameters. The core algorithm involves MRC weighting calculations combining signals from both paths, with key functions handling channel modeling, DF protocol implementation, and performance metric computation.