Relay Selection in Cooperative Communication using Log-Likelihood Ratio over a Two-State Markov Fading Channel

Abstract

The demand for higher data rates and seamless coverage in real-time applications is a primary driving force behind the rapid evolution of wireless communication technologies. A critical challenge in the development of advanced communication systems is ensuring both reliability and spectral efficiency. One of the promising solutions to this challenge is the implementation of Multiple-Input Multiple-Output (MIMO) systems, which significantly enhance performance. Cooperative relaying, in particular, extends the benefits of MIMO technology to devices equipped with only a single antenna. By enabling resource sharing in environments where some users may be inactive, cooperative relaying introduces cooperative diversity, enhancing overall system performance. The adaptability of cooperative communication protocols allows them to be effectively utilized in various applications, such as sensor networks and Mobile Ad-hoc Networks (MANETs). This paper proposes a novel method based on the log-likelihood ratio for selecting relays, and models the dynamic, time-varying wireless channel as a two-state Markov process, incorporating both Rayleigh and Rician fading models. The proposed approach's effectiveness is demonstrated through extensive simulation results, which showcase notable performance improvements in terms of reliability and data throughput. The findings suggest that this method can play a crucial role in optimizing cooperative communication systems.