Error performance analysis of signal superposition coded cooperative diversity

This paper analyzes the error performance of a coded cooperative diversity system employing the Euclidean superposition of two BPSK-modulated signals. For an example using a convolutional code on block fading channels, the results show excellent agreement with computer simulations. The analysis makes it possible to optimize the power allocation between the local and relay signals numerically, circumventing the need for time consuming Monte Carlo simulations. Similarly, the analysis demonstrates how the power allocation can be "tuned" to compensate for unbalanced uplink channels and/or to provide unequal error protection to the data from the two cooperating nodes.