BER analysis of BPSK signaling in Ricean-faded cochannel interference

The bit error rate of a binary phase shift keying signal in Ricean-faded cochannel interference is studied. A precise bit error rate expression based on a characteristic function method is derived for a bandlimited binary phase shift keying signal corrupted by an arbitrary number of asynchronous Ricean-faded interfering signals. For the special case when there is one synchronous Ricean-faded interfering signal, a Chernoff bound analysis is performed and it predicts that the error floor of the desired user signal decreases with an increase of the Rice factor in the interfering user´s fading channel. However, our precise bit error rate analysis results reveal that the opposite phenomenon can also happen, in particular when the signal-to-interference power ratio is low. A saddle-point approximation based error rate analysis is also provided. It is shown that this approximation is highly accurate. An asymptotic analysis based on the saddle-point approximation further reveals that a minimum signal-to-interference power ratio is required to have the desired user´s error rate performance improved by a less-faded interfering signal.