Performance analysis of GMSK with CSDD and CSDDD scheme in land mobile to mobile channel with random frequency shifts and CCI

In land mobile to mobile (LMM) channel, random frequency shifts (RFSs) may be introduced into the carrier frequency as a result of the Doppler effect due to the motion of transmitter (Tx) and receiver (Rx). Hagras et al. (2000) showed that the performance of center sampling differential detection (CSDD) in an LMM channel yields poor performance in the presence of RFSs. The main object of this paper is to study the performance of center sampling double differential detection (CSDDD) scheme introduced in Abdelkader and Fred (1986) in an LMM channel and compare its performance with the CSDD scheme. The performance of the CSDD and CSDDD schemes are analyzed in a two path Rayleigh fading channel taking into account frequency selective fading (FSF), RFS, intersymbol interference (ISI), Doppler frequency shift, cochannel interference (CCI), and additive white Gaussian noise (AWGN). It is shown that the CSDDD scheme in the LMM channel has the potential to compact the effect of RFS and its performance is better than the CSDD scheme when RFSs are introduced into the carrier.