BER performance of three-phase digital network coding employing combined TAS/alamouti OSTBC-OFDM in the presence of imperfect channel state information

Abstract

This paper examines the average bit error rate (BER) performance of a three-phase digital network coding (3PDNC) scheme that employs combined transmit antenna selection (TAS)/Alamouti orthogonal space-time block coding (OSTBC) for orthogonal frequency-division multiplexed (OFDM) signal transmission in frequency-selective Rayleigh fading channels. By performing Monte Carlo simulations for numerous realizations of fading channels and transmission frames, the average BER performance of the 3P-DNC scheme consisting of a singleantenna relay serving as a broadcasting node between two source terminals that are out of each other's coverage, has been observed for both uncoded and convolutional-coded transmission of Mary modulations. By considering erroneous channel estimation in both the relay node and the source terminals that results in combining and TAS imperfections at the relay node and the source terminals, respectively, the variation of the average BER performance has been investigated. The average improvement gathered by performing TAS in source terminals has been shown to be in terms of average SNR gains when compared to the Alamouti-coded OFDM signal transmission without TAS. Also, by focusing on the practical imperfections caused by the channel estimation process, the deteriorations faced in the average BER performances have been exhibited. © 2017 Elsevier B.V., All rights reserved.