دانلود رایگان مقاله توزیع قدرت بهینه در شبکه بی سیم غیر باینری مبتنی بر کد LDPC

Abstract

This work analyzes the optimal power allocation in coded cooperative communication systems with a single relay and using the amplify-and-forward protocol. Non-binary low-density parity-check (LDPC) codes are used at the source and a fast Fourier transform (FFT)-based decoding algorithm is employed at the destination. We study the power distribution between the source and the relay based on the minimization of the LDPC bit error rate (BER) performance at the destination as well as on the information theoretic measures such as the channel capacity and outage probabilities. The optimal power allocation estimated by the LDPC performance simulation corresponds to the capacity/outage probability results. In addition, BER comparisons of the coded systems (cooperative and noncooperative) are carried out for some typical cooperative scenarios.

6. Final comments

In this work, we presented an analysis of the optimal power allocation in an LDPC coded cooperative network with a single relay operating with the AF protocol. The BER, channel capacity and outage probability were used as performance metrics to find the optimal power distribution between the source and the relay in two cooperative scenarios. We identify scenarios for which the choice of LDPC codes with non-binary fields provide coding gains relative to LDPC binary codes. In general, the optimal power allocation predicted by the LDPC performance simulation and by the capacity/outage probability results are in good agreement. The equal power allocation scheme tends to the optimal when the relay gets closer to the source. We compared the power allocation and the system performance of the cooperative system to those of the point-to-point communication system. We also observed that the optimal energy ratio does not depend on the field size.