Bounds on the performance of turbo codes on Nakagami fading channels with diversity combining

We derive bit error performance bounds for turbo codes on Nakagami fading channels with diversity combining. We first derive the average pairwise error probability expressions for turbo codes with maximal ratio combining (MRC), equal gain combining (EGC), and selection combining (SC) on Nakagami fading channels. Using the pairwise error probability expressions and the union bounding technique, we then obtain bounds on the bit error probability of turbo codes for MRC, EGC, and SC diversity schemes. We present the modified log-MAP turbo decoder for MRC, EGC, and SC, and compare the analytical bounds with simulation results for the special case of 2-antenna diversity with Nakagami parameter m=1 (i.e., Rayleigh fading). Results indicate that the EGC scheme with turbo coding performs close to MRC scheme for i.i.d Rayleigh fading.