DELTA MODULATION FOR CHANNEL FEEDBACK IN TRANSMIT DIVERSITY WIRELESS COMMUNICATION SYSTEMS

摘要

A method is described herein for reducing the number of feedback bits needed to send channel state information over a feedback channel from a receiving unit (102; 104) (e.g., mobile terminal, base station) to a transmitter unit (104; 102) (e.g., base station, mobile terminal) in a wireless communication system (100). In the embodiment, the receiver unit (102; 104) is capable of performing the following steps: receiving a pilot signal from a transmit antenna located at a transmitter unit (104; 102); analyzing a channel tap associated with the transmit antenna (106-1; 106-2 … 106-3) and exploiting the temporal correlations of the channel tap to generate the following (i) a delta-modulated feedback bit indicative of a real part of a complex coefficient of the channel tap associated with the transmit antenna (106-1; 106-2 … 106-3) and (ii) a delta-modulated feedback bit indicative of an imaginary part of the complex coefficient of the channel tap associated with the transmit antenna; and (3) sending the two feedback bits over a feedback channel to the transmitter unit (104; 102) which analyzes the two feedback bits, and other feedback bits corresponding to other channel taps of this and other transmit antennas (106-1; 106-2 … 106-3), to optimize the subsequent transmission of data to the receiver unit (102; 104).