Receiver design and cochannel interference mitigation for micro-cellular wireless systems

The number of users subscribed to wireless communication services has been growing exponentially during the past decade. New sophisticated wireless services are being added. Demands for high data rates and capacity over the wireless channel at lower cost are enormous. Multipath fading, cochannel interference (CCI), multiple access interference (MAI) and adjacent channel interference (ACI) are the prime factors affecting the capacity and the bit error rate (BER). In the literature, a considerable amount of research thrust has been focused to combat these factors. Many diversity techniques were proposed to combat the multipath fading. Optimal maximum likelihood receivers and many suboptimal receivers were proposed to combat cochannel interference and multiple access interference.; In this thesis, interference whitening receivers and conventional space diversity receivers are investigated to combat the CCI and MAI in micro-cellular fading environments. The interference whitening receivers exploit the correlation in the spectrum of CCI and MAI to mitigate their effects on detection of the desired signal. A whitening matched filter is introduced instead of the conventional matched filter. While maximizing the signal-to-noise plus interference ratio (SNIR), the whitening matched filter introduces intersymbol interference (ISI) in the desired sample. A fractionally spaced linear minimum mean square error (MMSE) equalizer is employed to combat the intersymbol interference. Average BER expressions are derived using characteristic function and Fourier series methods. Notably, the complexity of this system does not grow with the number of users as do the complexities of the optimal or suboptimal multiuser receivers. The whitening matched filter receiver uses the knowledge of the value of the total interference power and the interferers' pulse shaping, information normally available at the receivers for power control, etc. or inexpensive to obtain.; The accurate BER and outage performances of conventional space diversity receivers in CCI and fading channels are studied. Bandlimited BPSK systems with two Nyquist pulse shapes, namely, spectrum raised-cosine (SRC) and Beaulieu-Tan-Damen (BTD) pulses are considered. Again, characteristic function and Fourier series methods are employed. It is shown that the BTD pulse outperforms the SRC pulse in all the cases considered.; The proposed receivers require only the total interference power and the pulse-shape of the interferers at the receiver. These parameters may be available at the conventional receiver for the power control and some diversity combining schemes. As the receiver structure changes with the parameters thus, these receivers are adaptive single-user receivers.