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 fadin g at the mobile which can significantly improve performance. Theoretical er ror formulas for convolutional codes are shown to be useful in optimising t he performance of some of these techniques. Performance results from a numb er of simulation studies are also presented. These can be used to determine the strengths and weaknesses of the algorithms and their effect on a typic al CDMA network. The effects of Rician fading and fast downlink power contr ol on transmit diversity are discussed.