Patent ID: 6895044

Claim:
A method for estimating a signal variance (VAR) received signal transmitted via a transmission channel, said method comprising the steps of: estimating an energy (RSSI) of the received signal, estimating an energy of (Emax) of channel impulse response taps, wherein estimating said signal variance of said received signal by subtracting the estimated energy of channel impulse response taps from the estimated energy of said received signal, such that said signal variance is obtained as: VAR=RSSI−Emax, wherein said estimated energy of the received signal is represented by a sum of all vector components of the received signal according to a relation of RSSI = ( ∑ i ⁢ ( Re ⁢ { y i } 2 + Im ⁢ { y i } 2 ) ) / N = E ⁡ ( y H ⁢ y ) / N with Re{y i } denoting a real component of the i-th vector component of the received signal y in vector representation, Im{y i } denoting an imaginary component of the i-th vector component of the received signal y in vector representation, y denotes the vector of the received signal, and y H denotes a conjugate complex transposition of the vector of the received signal, and wherein said estimated energy of said channel impulse response taps is represented by a sum of all vector components of the channel impulse response according to a relation of Emax = ( ∑ i ⁢ ( Re ⁢ { h i } 2 + Im ⁢ { h i } 2 ) ) / N = E ⁡ ( h H ⁢ X H ⁢ hX ) / N with Re{h i } denoting a real component of the i-th vector component of the channel impulse response h in vector representation, Im{h i } denoting an imaginary component of the i-th vector component of the channel impulse response h in vector representation, h denotes the vector of the channel impulse response, h H denotes a conjugate complex transposition of the vector of the channel impulse response, and X represents a training sequence in vector representation, the training sequence being such that a product of the training sequence with its conjugate complex transposition X H makes “1” and wherein N (N is a natural number) represents the length of a symbol sequence of the received signal y.