Abdurazak Mudesir

• In a wireless communication environment characterized by dynamic channels, high influence of interference, bandwidth shortage and strong demand for quality of service (QoS) support, the challenge for achieving maximal spectral efficiency and high data rate is unprecedented. The data rate achievable now with most practical systems is in the range of tens of megabits per second. As discussed by Shannon, the channel capacity limit is not dependent on the transmitter/ receiver technologies but on the properties of the communication channel. The SIR in the presence of multipath fading, shadowing and path loss is a very important parameter for studying the capacity of a wireless system. This thesis presents a statistical analysis of the SIR for next generation wireless networks. First a new analytical formula for the PDF of the signal to interference ratio for a single interferer is presented. Monte Carlo simulation is used to validate the analytical formula. However in a realistic environment there are often more than one active interferers in a given cell. Two distinct approaches are used to study the effect of multiple interferers on the statistics of the SIR. The sum of random vector approach is used to find the PDF of the SIR for the multiple interference scenario. Laguerre polynomial approximations are used to simplify the problem of finding the PDF of the SIR. A new algorithm is proposed to find the optimum free parameter for the Laguerre approximation. However even with the optimum free parameter, the computational burden required to approximate the PDF of the SIR for multiple interferers with a Laguerre polynomial was impractical. Therefore an alternative characteristics function approach was proposed in this thesis. In this approach the path loss, shadowing and multipath fading are assumed to be dependent random variables. The statistical analysis of the SIR is used to study the TDD inter-cell interference in a self-organizing user deployed femtocell systems.