Downlink transmit diversity schemes for CDMA networks

Transmit diversity schemes that have been proposed for the downlink in CDMA networks are discussed. They provide diversity gain against Rayleigh fading at the mobile which can significantly improve performance. Theoretical error formulas for convolutional codes are shown to be useful in optimising the performance of some of these techniques. Performance results from a number of simulation studies are also presented. These can be used to determine the strengths and weaknesses of the algorithms and their effect on a typical CDMA network. The effects of Rician fading and fast downlink power control on transmit diversity are discussed