Special Issue Article Open Access

Joint Channel and Carrier Frequency Offset Estimation in Decode and Forward Multi-Relay Cooperative Networks using the PX-EM Algorithm

Abstract

Cooperative networks employing multiple relays subject to multiple carrier frequency offsets (MCFOs), which lead to time varying channels and error in detection. This paper deals with joint estimation of channel and MCFOs in flat-fading decode and forward (DF) relaying cooperative networks using parameter expanded expectation maximization (PX-EM) algorithm. The proposed algorithm is to increase the convergence speed of existing expectation conditional maximization (ECM) and space alternating generalized expectation maximization (SAGE) algorithms. After estimation maximum likelihood (ML) decoding is done at the destination in the presence of MCFOs. Simulation results show that the number of iterations of proposed algorithm is lesser than the existing algorithms and also achieves the Cramer-Rao Bound Lower (CRLB) and finally ML decoding improves the performance of the system.

D. Dhivya Bharathi, S. Sundaravadivelu