Patent ID: 7539260

Claim:
A method of detecting number of transmit antennas of a wireless communication system, the method comprising: receiving samples of training symbols that are cyclically shifted with respect to one another and transmitted from the plurality of the transmit antennas; performing Fourier transform operations on the received samples of the training symbols to generate frequency-domain values associated with the received samples; multiplying the associated frequency-domain values of the received samples with known frequency-domain representation of the training symbols on each sub-carrier of a reference transmit antenna to generate multiplied values; computing a transmission channel impulse response; and detecting number of shifted impulse responses in the channel impulse response, wherein the detected number of shifted impulse responses represents the number of transmit antennas applying cyclic window integration on the channel impulse response; detecting presence or absence of a peak value in each cyclic window to detect the number of shifted impulse responses in the impulse response; wherein the frequency-domain value y q (i) on receive antenna q and subcarrier i is defined by the following expression: y q ⁡ ( i ) = C 1 ⁢ ∑ n = 0 N c - 1 ⁢ r q ⁡ ( n ) ⁢ exp ⁡ ( - j2π ⁢ ⁢ i ⁢ ⁢ n N c ) wherein r q (n) represents the n-th received time-domain sample on the q-th receive antenna, wherein the Fourier transform window of the training symbols includes N c, samples, and the first sample of the Fourier transform window corresponds to n=0, and wherein C 1 is a normalization constant.