Patent ID: 7843872

Claim:
A method of wireless communications, the method comprising: receiving from a transmitter a signal representing a known sequence of symbols, the signal comprising a plurality of sub signals transmitted over a plurality of sub channels; determining channel responses at the plurality of sub channels; and determining a reception of the known sequence, the determining comprising treating the channel responses at the plurality of sub channels in a differential manner to cancel out channel phase responses and obtain channel amplitudes, wherein determining a reception comprises applying the formula: FDDC ⁡ ( x ) = ∑ k = 0 Plen - 2 ⁢ ⁢ FftOut ⁡ ( Y 0 + StepSize × k ) × conj ⁢ { FftOut ⁡ ( Y 0 + StepSize × ( k + 1 ) ) } × DP ⁡ ( x , k ) where: FDDC (x) is a measure of the reception of sequence x, a Fourier transformation has been applied to the signal representing x to produce Fourier transformation bins (FT bins), and there is a constant difference in FT bins between consecutive bits of x, StepSize is the constant difference in FFT bins between consecutive bits of sequence x, Plen is the length of sequence x in bits, FftOut(y) is the complex value of bin y of the FT bins, given by the formula: Fft Out( Y 0 +StepSize× k )= P ( x,k )× H ( Y 0 +StepSize× k ) Y 0 is the bin to which the first bit of sequence x is transmitted, DP(x,k) is bit k of sequence x in differential form, H(y) is the channel response at FT bin y, and P(x,k) is the kth bit of sequence x.