Patent ID: 7539259

Claim:
A method of communication using Orthogonal Frequency Division Multiplexing (‘OFDM’) from a transmitter comprising a plurality of transmit antenna means and a receiver comprising at least one receive antenna means, the method comprising: generating bit streams and corresponding sets of N frequency domain carrier amplitudes ({tilde over (s)}(kN+j), 0≦j≦N−1) modulated as OFDM symbols subsequently to be transmitted from the transmitter, where k is the OFDM symbol number and j indicates the corresponding OFDM carrier number; inserting affix information into guard intervals between consecutive time domain OFDM symbols; transmitting said time domain OFDM symbols including said affix information from said transmitter to said receiver; using said affix information at the receiver to estimate the Channel Impulse Responses (H lm between the lth transmit and mth receive antenna) of the transmission channels between said transmitter and said receiver; and using the estimated Channel Impulse Response (Ĥ lm between the lth transmit and mth receive antenna) to demodulate said bit streams in the signals received at said receiver, wherein said affix information is known to said receiver as well as to said transmitter, and is mathematically equivalent to a vector (c D ) that is common to said time domain OFDM symbols multiplied by at least first weighting factors (α k ) that are different for one time domain OFDM symbol (k) than for another and second weighting factors (w i (k)) that enable one of said transmit antenna means (i) to be distinguished from another; wherein said transmitter uses N t transmit antenna means and the receiver uses N r receive antenna means, M′ consecutive time domain OFDM data symbols are encoded by a specific space-time encoder M such that the encoder M produces M time domain OFDM data signals outputs for each of the N t transmit antenna means, and said vector (c D ) is encoded by a specific space-time encoder W such that the encoder W produces M affixes for each of the N t transmit antenna means corresponding to said affix information weighted by said first and second weighting factors (α k ) and w i (k), the resulting affixes being inserted between time domain OFDM data symbols for each of the N t transmit antenna means.