Channel estimation for code-division multiple-access (CDMA) communication using both common pilot channel and pilot symbols carried on an individual channel.

摘要

A code-division multiple-access communication system in which a base station transmits data signals using individual channels having individual user data and a common pilot channel in which symbols are known. The data signals in an individual channel and the common pilot channel are each mixed with a respective other signal at a mobile station so that said mobile station may use at least one of the individual channel or common pilot channel to carry out channel estimation in order to restore a phase change in data transmitted from said base station. In particular, when the mobile station is near the base station, the mobile station carries out channel estimation using the common pilot channel, and if the mobile station is far away from the base station, the channel estimation is carried out using a pilot symbol of said individual channel. A common pilot channel-use reverse diffusion unit 3 generates common pilot data, while an individual channel-use reverse diffusion unit 4 generates individual channel data. Power calculating unit 5, 6 converts respective output data items of the common pilot channel-use reverse diffusion unit 3 and the individual channel-use reverse diffusion unit 4 into power values, a larger one of which is then determined by a comparator 7. A selector unit 8 selects the data item having a thus- determined larger power value of those output data items of the reverse diffusion units 3, 4. A channel estimating unit 9 estimates the channel using data symbols for the data item thus selected by the selector unit.