On the Impact of Imperfect Cophasing in Uncoded and LDPC-Coded EGC Receivers over Generalized Fading Channels

We study the performance of unbalanced partially coherent uncoded and low-density parity-check (LDPC)-coded equal gain combining (EGC) receiver operating over generalized a-mu fading channels, when the binary phase-shift keying (BPSK) and quaternary phase-shift keying (QPSK) are used. We determine the bit-error ratio (BER) performance degradation due to the imperfect reference signal recovery, receiver unbalancing and fading. Furthermore, we design large girth quasi-cyclic LDPC code with high code rate, suitable for use in communications over generalized fading channels. The proposed LDPC code does not exhibit the error floor phenomena, in the region of interest, even in the presence of imperfect cophasing and receiver unbalances.