Patent ID: 8194558

Claim:
An adaptive modulation and coding method, in which adaptive modulation and coding (AMC) is applied in a channel environment considering user mobility, the adaptive modulation and coding method comprising: measuring a first channel parameter and a second channel parameter using first and second symbols sequentially received, respectively; estimating a channel quality considering a time delay between measurements of the first and second channel parameters using the first and second channel parameters; and transmitting information for the estimated channel quality if a variation of channel parameter between the first and second channel parameters is equal to or greater than a prescribed threshold, wherein the first and second channel parameters are averages of per subcarrier signal-to-noise ratios of the first and second symbols received via at least one or more subcarriers, respectively, wherein the channel quality considering the time delay is estimated by a formula of SNR = 1 N ⁢ Q N n = 1 ⁡ (  H n k  2 +  H n k - 1  2 2 ⁢ E s σ n 2 ) ⁢ ⁢ or SNR = 1 N ⁢ Q N n = 1 ( (  H n k  2 +  H n k - 1  2 2 + ( 1 -  ρ  2 ) ⁢ σ h 2 ) ⁢ ( E s σ n 2 ) , where the N is the number of the subcarriers (N>I), the E s is an average signal energy, the σ n 2 is a noise energy, the H n k is the second channel parameter of an nth subcarrier at a symbol k, and the H n k-1 is the first channel parameter of the nth subcarrier at a symbol k−1, and where the σ h 2 is an average energy of channeland the p is a parameter calculated using Bessel function by considering a Doppler frequency and the time delay.