Performance evaluation of QAM and QPRS systems with interfering channels in frequency selective fading

An analytical technique is developed to evaluate the error rate performance of M-ary quadrature amplitude modulation (QAM) and quadrature partial response signalling (QPRS) in the presence of adjacent channel and cochannel interference with frequency selective fading. Error probability expressions are derived and evaluated numerically using the method of saddle-point integration. In addition to the above impairments, the system model also incorporates other disturbances, namely stationary white gaussian noise, quadrature channel interference, random timing misalignments and carrier phases of interfering signals. An extensive set of results and comparisons are presented.