Patent ID: 7609613

Claim:
A diversity transmitter for use in an OFDM transmission protocol which diversity transmitter comprises: a diversity generator for receiving and diversifying OFDM transmit symbols, and outputting diversified OFDM symbol matrices (DOSM), DOSM symbols within each DOSM being divided into at least two primary streams each comprising different DOSM symbols, a transmit processor for receiving said at least two primary streams of DOSM symbols, and for transforming said each DOSM symbol from the frequency domain into the time domain, and outputting time domain OFDM symbols (TDOSs), a cyclic delay circuit for dividing at least one of said primary streams of TDOSs into at least two branches of identical TDOSs, each branch for supplying a respective spatial channel for transmission to a receiver, the arrangement being such that, in use, said cyclic delay circuit applies a cyclic time shift to a TDOS in at least one of said branches before transmission which cyclic time shift is performed modulo the length of said TDOS and is a multiple of a guard period of said OFDM transmission protocol.