In order to validate the results of simulating the performance of a communication system operating over fading channels, we often compare the performance of the simulated systems against similar systems operating over ideal AWGN channels and/or over a Rayleigh fading channels with ideal phase references.
Compare the BER versus Eb/N0performance of a QPSK system operating over an AWGN channel with an integrate-and-dump receiver with a differential QPSK system over a Rayleigh fading channel with AWGN. The received signal (bandpass case) is of the form
Where Ts is the symbol duration, n(t) represents the AWGN, and φk represents the differential QPSK modulation. In addition, Rk and θk represent the amplitude and phase associated with the Rayleigh fading. Assume that Rk and θkchange slowly with respect to the symbol rate.