Performance analysis of digital communications systems with fading and interference

The growing deployment of wireless infrastructures and the decreasing cost of services have resulted in an exponential increase in the usage of wireless communication devices in different fading environments over the past decade. The performance of mature wireless cellular systems remains limited by fading and interference from other user signals. This thesis contributes to the accurate bit error rate (BER) performance analysis of a coherent binary phase shift keying (BPSK) modulation in a general fading and interference environment, as well as contributes to the estimation of the Nakagami- m fading parameter.; A generic BPSK direct-sequence code-division multiple access (DS-CDMA) system using random spreading sequences in flat Rayleigh fading is first considered. A tractable average BER expression is derived using a characteristic function method. The precise BER can be obtained for a system with large processing gain and an arbitrary number of users with modest computational complexity. The result is used to assess the accuracies of several widely used approximations. These results are then extended to a flat Nakagami-m fading channel.; Error analysis for bandwidth-efficient BPSK in a generalized Nakagami/Nakagami fading and cochannel interference (CCI) environment is studied. A tractable analytical BER expression is derived and used to study the effects of fading of an interfering signal on the desired user BER performance. It is found that fading of an interfering signal worsens the BER of the desired signal rather than improving it. The performance of a new novel pulse shape in fading and CCI is also studied. It is shown both analytically and numerically that this novel pulse outperforms the widely used raised-cosine pulse.; The estimation of the Nakagami-m fading parameter is extensively studied. Both moment-based and maximum-likelihood based estimations are considered. Several new estimators are proposed and their properties are thoroughly examined.