BER analysis of a noncoherent demodulation of unbalanced DQPSK DSSS

A conventional demodulator for an unbalanced QPSK direct sequence spread spectrum (DSSS) signal requires carrier coherence in order to prevent cross-talk between the in-phase and quadrature (I & Q) channels of the despreading process. A noncoherent demodulator which tolerates this cross-talk has been proposed, with applicability to pilot-less burst transmission protocols. The paper focuses on the development and verification of an analytic model for the BER performance of this demodulator, and shows that, although the noise contributions of the cross-talk terms can be high, the resultant impact on BER is only slight.