Patent ID: 8363739

Claim:
A transmitter comprising: sub-carrier mapping circuitry adapted to map data information for modulation on sub-carriers of a plurality of traffic symbols and map pilot information for the transmitter for modulation on sub-carriers of at least one pilot symbol for a transmit time interval; pilot generation circuitry adapted to generate the pilot information for the transmitter; and modulation circuitry adapted to modulate the data information onto at least certain of the sub-carriers of the plurality of traffic symbols and modulate the pilot information for the transmitter onto at least certain of the subcarriers of the at least one pilot symbol, such that the pilot information for the transmitter and pilot information for other transmitters are orthogonally modulated on the sub-carriers of the at least one pilot symbol in the transmit time interval; wherein the at least one pilot symbol is a plurality of short pilot symbols, each short pilot symbol separated by at least one of the plurality of traffic symbols within the transmit time interval and having a Fourier transform length less than that of each traffic symbol.