Patent ID: 7369620

Claim:
A channel noise estimating method applied to a multi-carrier system consisting of K subchannels over which original data symbols (X k [n]) (where n is the discrete time index, kε{1, 2, . . . , K} is the subchannel index) are transmitted in a frequency-domain from a transmitting unit to a receiving unit, the noise estimating method comprising the acts of: reconstructing simulated input data symbols (X′ k [n]) that simulate the original data symbols (X k [n]); delaying the actual received data symbols (R k [n]) such that the delayed actual received data symbols (Q k [n]) are synchronous to the simulated input data symbols (X′ k [n]); calculating a channel response estimate (W k [n]) of one subchannel k based on said delayed actual received data symbols (Q k [n]) and said simulated input data symbols (X′ k [n]) according to the Least Mean Square algorithm; estimating virtual received data symbols (Y k [n]) based on said channel response estimate (W k [n]) and the simulated input data symbol (X′ k [n]); and calculating a different quantity (e k [n]) between the delayed actual received data symbol (Q k [n]) and the estimated virtual received data symbols (Y k [n]) to represent the channel noise of said subchannel k.