Copyright Statement General Copyright and Disclaimer Packetised Wireless Communication Systems in Interference Limited Environments

There is a strong likelihood that future wireless communication systems will employ packetisedtransmission techniques. Such an approach would provide a number of benefits, including theability to integrate with emerging wired systems based on Asynchronous Transfer Mode (ATM).In addition, packet-based wireless networks would allow for diverse traffic types and inparticular, speech and data traffic, to be integrated more readily.This thesis presents theoretical models and performance studies for various interference limited,packet-based, speech and data wireless communication systems. Two packetised random accessprotocols are considered for investigation, namely Slotted ALOHA (S-ALOHA) and PacketReservation Multiple Access (PRMA). The S-ALOHA protocol is designed specifically for datatraffic, whereas the PRMA protocol is optimised for speech traffic, with the ability to also caterfor data traffic.Previously published research into S-ALOHA and PRMA has generally focused on theperformance of these protocols in idealised single cell systems, free from cochannel interference.Previous studies have normally only considered simple signal propagation models that give littleor no consideration to signal variability. A common assumption made in previous studiesassumes that all packets involved in collisions with other packets are lost, while those packetsreceived in the absence of other packets are received successfully.In this thesis, the performance of S-ALOHA and PRMA in more realistic multiple cellconfigurations, namely the outdoor cellular and in-building pico-cellular environments, has beenconsidered. The fluctuations in received signal strengths have been modeled in this thesis usingnarrowband statistical propagation models. In addition, the assumption relating to packetcollisions has been reconsidered in this thesis because practical receivers are often capable oflocking onto one packet in the presence of other intra-cell and inter-cell interfering packets, dueto the receiver capture effect. A capture probability model has been developed in this thesis,which defines the probability of a desired packet capturing the central cell base station in thepresence of both intra-cell and inter-cell interfering packets. Accompanying Markov analysistheory has been developed to analyse the performance of multiple cell S-ALOHA and PRMAsystems.Having developed the necessary framework, it has been possible to successfully analyse variousmultiple cell S-ALOHA and PRMA systems. These include a multiple cell data-only S-ALOHAsystem, multiple cell speech-only PRMA systems with and without selection diversity andspeech packet retransmission and an integrated speech-data multiple cell PRMA system withselection diversity and speech packet retransmission.