Relay Selection for OFDM Based Decode and Forward Cooperative Systems

In this paper, we address two novel relay selection techniques: Joint Minimum Subcarrier (JMSub) and Joint Mutual Information (JMInf), for multicarrier cooperative systems when decode and forward (DF) strategy is employed. The theoretical outage probability or performance bound is analytically derived. Simulation results illustrate us that if the outage is defined as the probability that the sum capacity of all occupied subcarriers is smaller than some predesigned threshold, JMInf performs better; whereas if the outage probability is calculated based on respective subcarrier, the situation is opposite. Specifically, the cooperative diversity amelioration is proportional to the number of subcarriers.