Equalisation of time variant communications channels: channel estimation based approaches

For the purpose of tackling the problem of equalisation in a time variant environment, two novel approaches are developed in which the separation of the channel estimation process from the equalisation process is attempted. Two linear filters; channel estimator and equalisation filter, are used to reconstruct the transmitted sequence. The gradient algorithm with degree-1 least-square fading memory prediction is adopted for the channel estimator. Using the results produced by the channel estimator, the coefficients of the equalisation filter are indirectly updated. Computer simulation results show that the two channel estimation based adaptive equalisers provide significant improvement in the case of a second order Markov communication channel model