| In wireless communications energy and spectrum resources are scarce and expensive, they must be efficiently managed to address the growing requirement of emerging applications. Intensive works have been dedicated to develop advanced processing technologies to improve the spectral efficiency. In decentralized multiple access system such as ad hoc network, interference represents the major performance inhibitor. Thus interference mitigating is one of the major research subjects in recent years. Several solutions have been proposed that consists on exploiting the particular structure of the interference which depend on the physical layer used. In fact, technologies like spread spectrum and multiple antenna provide a number of degrees of freedom that when properly exploited increase the system tolerance to interference.;In the context of spread spectrum different multiuser receiver schemes was introduced. The well known Minimum Mean Square Error, MMSE, is the multiuser receiver that maximize the Signal to Interference plus Noise Ratio, SINR. The equivalent solution in the context of antenna array is known as Optimum Combining, OC, receiver. Studying the reliability of these receiver is an important issue and have been the subject of extensive work in the literature. Despite this, there is still much work to do to understand their limits in many contexts.;In the first part, we derive the outage probability for the interference cancellation receiver and the optimum combining receiver. In the second part we establish an analysis of a number of opportunistic routing strategies and we quantify the performance gains achieved by employing adaptive antenna array systems in a multi-hop network.;This thesis address the issue of quantifying the performance gain that can be achieved by using advanced signal processing technologies in the context of Ad Hoc networks, namely, interference cancellation and adaptive antenna array systems. |
