Patent ID: 8279914

Claim:
A signal to noise power ratio (SNR) estimation system for multi-carrier communication system, comprising: a phase rotator for receiving a quadrature amplitude modulation (QAM) symbol {Y i,k } and a channel estimation signal {Ĥ i,k } and performing a phase rotation on the symbol and signal to generate a rotated QAM symbol {{tilde over (Y)} i,k } and a rotated channel estimation signal {|Ĥ i,k |}, wherein i is a frame index and k is a sub-carrier index; a power estimator connected to the phase rotator and having N TPS sub-power estimators to perform a power estimation on the rotated QAM symbol {{tilde over (Y)} i,k } in each sub-carrier to generate a signal power index S T and a noise power index N T , where N TPS is a positive integer; a channel gain calculator connected to the phase rotator for generating a subcarrier channel gain signal P H T and an averaged channel gain signal P H according to the rotated channel estimation signal {|Ĥ i,k |}; an average and selection device connected to the power estimator and the channel gain calculator for selecting and generating an averaged signal power set {{tilde over (S)} m μ }, an averaged noise power set {Ñ m μ } and an averaged channel gain set {{tilde over (P)} m μ } according to a criterion indicator μ, the signal power index S T , the noise power index N T and the subcarrier channel gain signal P H T ; and a combination and calculation device connected to the average and selection device and the channel gain calculator for generating an estimated SNR γ μ according to the criterion indicator μ, the averaged signal power set {{tilde over (S)} m μ }, the averaged noise power set {Ñ m μ }, the averaged channel gain set {{tilde over (P)} m μ } and the averaged channel gain signal P H .