Modeling conditional error probability for hybrid decode-amplify-forward cooperative system

The error probability is one of the important metrics used to measure the performance of cooperative relay-based systems. Conventionally, the error probability analysis assumes no information about the condition of the Source-Relay link. In this paper, we show that this assumption could result in over or under estimation of the error probability and therefore affects the accuracy of the analysis which is essential to design optimum relay-based system. Therefore, we propose the mathematical model of conditional error probability, in which relay decision information is considered in the performance analysis of cooperative relay-based systems. The mathematical model for Hybrid Decode-Amplify-Forward cooperative system is utilized in order to validate the necessity of modeling conditional error probability and evaluate the overall system performance. The accuracy of the derived analytical expressions are validated via Monte Carlo simulations. Results show that, there is substantial difference between the conventional and the conditional error probability, which depends on relay decision information. Finally, the derived expressions provide accurate analytical tool to analyze and design relay-based cooperative systems for various Source-Relay channel conditions.