Abstract
In the first part of this thesis, the information capacity of time-varying fading channels is
analysed using finite-state Markov channel (FSMC) models. Both fading channel amplitude
and fading channel phase are modelled as finite-state Markov processes. The effect of the
number 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 channel
gain partitions is larger than 4 to 8 times the number of channel input levels. The rapid
FSMC capacity saturation with a small number of fading channel gain partitions can be
used 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 capacity
estimates for fading channels than high-order FSMC models, especially when channel states
are poorly observable in the presence of channel noise.
To explain the effect of memory order on the FSMC capacity, the capacities of high-order and
low-order FSMC models are analytically compared. It is shown that the capacity difference
is caused by two factors: 1) the channel entropy difference, and 2) the channel observability
difference between the high-order and low-order FSMC models. Due to the existence of the
second factor, the capacity of high-order FSMC models can be lower than the capacity of
low-order FSMC models. Two sufficient conditions are proven to predict when the low-order
FSMC 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’ with
unequal probabilities. The unbalanced source distribution is used as a priori known signal
structure at the receiver for channel estimation. Compared to pilot-symbol-assisted channel
estimation, the proposed channel estimation technique can achieve a superior receiver bit
error rate performance, especially at low signal to noise ratio conditions.