Patent ID: 7756222

Claim:
A method of dynamic quantization in an orthogonal frequency division multiplexing (OFDM) system, the method comprising: receiving quadrature amplitude modulation (QAM) symbols for each of a number of “m” sub-carrier channels, m being an integer greater than 1; computing a channel power P CH (i)=|G CH (i)| 2 for each of the m sub-carrier channels, where G ch (i) is the i -th sub-carrier channel frequency response, i being an integer from 0 to m−1; computing P max = max i ⁢ { P CH ⁡ ( i ) } , where the max{ } function computes the maximum value of P CH (i); computing P min = min i ⁢ { P CH ⁡ ( i ) } , where the min{ } function computes the minimum value of P CH (i); setting a first frequency selectivity indicator (FSI) value if P max ≧T*P min and setting a second FSI value if P max <T*P min , wherein T is a predetermined threshold value; determining a quantization parameter, K, which is a positive real number selected according to the first or second FSI value; applying an exponential function to the received QAM symbol, x i for the i-th subcarrier, according to the following equation: g ⁡ ( x j ) = sgn ⁡ ( x j ) ⁡ [ 1 - exp ⁡ ( -  x j  K ) ] , sgn ⁡ ( x j ) = { 1 , x j > 0 0 , x j = 0 - 1 , x j < 0 , where g(x i ) is a transform output of x i ; determining a set of (2 q −1) quantization thresholds according to the first and second FSI values for a q-bit quantization output in the OFDM system, wherein q is a positive integer; and quantizing the exponential function outputs, g(x i ) for all the sub-carriers.