Channel estimation for multi-user detector DS-CDMA receivers

We consider a multi-user detector for the downlink of a DS-CDMA system with similar parameters to the UTRA-TDD specification, placing particular emphasis on the various trade-offs which must be accommodated to obtain a sufficiently accurate estimate of the multipath channel and thus permit reliable data transmission. We demonstrate that choosing parameters solely to optimise the mean square error of the channel estimate is sub-optimal from the point of view of overall error performance.