Patent ID: 8599911

Claim:
An apparatus for estimating a signal to noise ratio (SNR), the apparatus comprising: a signal power estimator configured for estimating power of a reception signal for each sector; noise power estimators each configured for estimating noise power for each sector; a minimum value selector configured for selecting a minimum value from among the noise powers for a plurality of sectors; and an SNR calculator configured for calculating the SNR based on the power of the reception signal for each sector and the minimum value, wherein the noise power for each sector is calculated using the equation below: σ ^ EB , s 2 = 1 K ⁢ (  F 0 , s  2 2 +  F K - 1 , s  2 2 + ∑ k = 1 K - 2 ⁢  F k , s  2 6 ) , ⁢ s = 0 , 1 , 2 , ⁢ where ⁢ ⁢ K = ⌊ N used 3 ⌋ , k is a preamble symbol index, N used is the number of subcarriers that may be used in the frequency domain, s is a sector index, and F k,s is defined by the equation below: F 0,s =X* 0,s Y 0,s −X 1,s Y 1,s F k,s =2 X* k,s Y k,s −X* k−1,s Y k−1,s −X* k+1,s Y k+1,s , k= 1, 2, . . . , K− 2 F K−1,s =X* K−1,s Y K−1,s −X* K−2,s Y K−2,s where X k,s is a signal transmitted by each sector, and Y k,s is the reception signal received by each sector.