Iterative intra- and inter-cell interference mitigation algorithms for the cellular CDMA downlink

The performance of a number of iterative interference mitigation receivers is investigated in the context of the CDMA downlink. Two types of receiver are considered, both based on spatio-temporal filtering but differing in the way in which the filter weights are initialised in the first iteration. In the first type, the filter weights are trained directly via time-multiplexed transmitted pilots. In the second type, the weights are computed based on explicit channel estimates derived via the transmitted pilots. Least squares and semi-blind (constant modulus) optimisation criteria are utilised. It is shown that, while the receivers of the second type are initialised via filter weights which do not strictly satisfy a specific optimality criterion, they do result in superior performance in subsequent iterations. The performance of the receivers is evaluated via link-level simulations involving 2- and 7-cell indoor and urban propagation environments.