TIME AND FREQUENCY CHANNEL ESTIMATION

摘要

There is described a method for use in a transmitter (12) having multiple antennas (A1, A2) in an OFDM-based radio communications system, comprising determining one or more known pilot symbols. The method comprises the steps of determining a periodic pilot transmission pattern, forming a block of OFDM symbols that includes the one or more pilot symbols and data symbols in accordance with a predetermined pattern, using a space-time coder to perform space and time coding by assigning certain ones of the OFDM symbols to be transmitted during a particular time slot from a selected one the multiple antennas to provide an associated OFDM symbol stream to each of the multiple antennas, and transmitting each OFDM symbol stream from its association antenna. The space-time coder provides a first OFDM symbol stream of multiple symbols in a first sequential order to a first antenna for transmission during a first time slot and provides a second OFDM symbol stream of the same multiple symbols in a second sequential order different from the first sequential order to a second antenna.