| The analysis of signal-to-interference ratio based handoff algorithms in a cross-correlated cochannel interference environment is proposed in this thesis. Conventional handoff algorithms use received signal strength to initiate a handoff rather than the signal-to-interference ratio. However, the signal-to-interference ratio is a better link quality indicator than the received signal strength because the received signal strength might be high because of excessive cochannel interference, which corresponds to a bad signal-to-interference ratio, which implies high bit error rate. Although the analysis of received signal strength based handoff algorithms have been extensively studied in the literature, the signal-to-interference based handoff algorithms did not enjoy the insight that can be brought by similar analysis techniques to the cellular radio system design. In the analysis, expressions for the probability of handoff, expected number of handoffs, and probability of being connected to a base station are derived under the assumption of a general class of cross-correlated log-normal shadowing between radio links, which is a realistic cochannel interference model. The results that are obtained through the analysis tools are in close agreement with the simulation results. Finally, we introduced a model for the handoff delay and performed the handoff delay analysis of both signal-to-interference and received signal strength based handoff algorithms. We conclude that we can reduce the mean number of handoffs as much as 3 to 4 times by introducing 10% to 15% handoff delay while having a slight increase in the uplink outage probability. |
