The error probability performance of Gray encoded QPSK scheme with co-channel interference in a slow fading indoor channel

A theoretical analysis of the error performance of a Gray encoded quadrature phase shift keying (QPSK) scheme in the presence of thermal Gaussian noise and a fading cochannel interference signal in a slow fading indoor wireless channel is presented. The exact error probability expression is presented in a closed form with the error manifesting the combined effect of noise and interference. The system model and the underlying assumptions are specified, and the problem is formulated. The expressions for the bit and symbol error rates are derived. The performance plots and conclusions are presented. It is shown that the exact bit error ratio and the symbol error can be expressed in a closed form