In the first part of this thesis, the information capacity of time-varying fading channels isanalysed using finite-state Markov channel (FSMC) models. Both fading channel amplitudeand fading channel phase are modelled as finite-state Markov processes. The effect of thenumber of fading channel gain partitions on the capacity is studied (from 2 to 128 partitions).It is observed that the FSMC capacity is saturated when the number of fading channelgain partitions is larger than 4 to 8 times the number of channel input levels. The rapidFSMC capacity saturation with a small number of fading channel gain partitions can beused for the design of computationally simple receivers, with a negligible loss in the capacity.Furthermore, the effect of fading channel memory order on the capacity is studied (from first-to fourth-order). It is observed that low-order FSMC models can provide higher capacityestimates for fading channels than high-order FSMC models, especially when channel statesare poorly observable in the presence of channel noise.To explain the effect of memory order on the FSMC capacity, the capacities of high-order andlow-order FSMC models are analytically compared. It is shown that the capacity differenceis caused by two factors: 1) the channel entropy difference, and 2) the channel observabilitydifference between the high-order and low-order FSMC models. Due to the existence of thesecond factor, the capacity of high-order FSMC models can be lower than the capacity oflow-order FSMC models. Two sufficient conditions are proven to predict when the low-orderFSMC capacity is higher or lower than the high-order FSMC capacity.In the second part of this thesis, a new implicit (blind) channel estimation method in time-varying fading channels is proposed. The information source emits bits ’0’ and ’1’ withunequal probabilities. The unbalanced source distribution is used as a priori known signalstructure at the receiver for channel estimation. Compared to pilot-symbol-assisted channelestimation, the proposed channel estimation technique can achieve a superior receiver biterror rate performance, especially at low signal to noise ratio conditions.
展开▼
