Patent ID: 7415063

Claim:
A method for estimating noise in a distributed record of data including data sampling that representing both signal and noise, providing that the signal is substantially in phase between adjacent data samples, said method comprising the steps of: dividing the record of data into an even number of equal intervals; compiling a reduced data record by subtracting from every other data sample in the record of data by one data sample that is adjacent to the every other data sample; and estimating a noise power in the signal relative to a signal power by calculating a variance of the reduced data record; wherein said step of compiling the reduced data record Y i is estimated from the record of data by the following formula Y i =x 2i-1 ( t )− x 2i ( t ); here, receiver i measures the signal x i (t) at time t; wherein said step of estimating the noise power in the signal relative to the signal power is calculated by calculating the standard deviation as a measure of magnitude of the noise, as represented by the following formula E ⁡ ( Y 2 ) = ⁢ 1 2 ⁢ N ⁢ ∑ i = 1 N ⁢ ( x 2 ⁢ i - 1 ⁡ ( t ) - x 2 ⁢ i ⁡ ( t ) ) 2 = ⁢ 1 2 ⁢ N ⁢ ∑ i = 1 N ⁢ ( s 2 ⁢ i - 1 ⁡ ( t ) - s 2 ⁢ i ⁡ ( t ) ) 2 + ⁢ 1 2 ⁢ N ⁢ ∑ i = 1 N ⁢ ( n 2 ⁢ i - 1 2 ⁡ ( t ) - n 2 ⁢ i - 1 ⁡ ( t ) ⁢ n 2 ⁢ i ⁡ ( t ) + n 2 ⁢ i 2 ⁡ ( t ) ) = ⁢ σ 2 ; wherein E(Y 2 ) is the expected value of Y 2 ; wherein the distributed record of data represents measurements from 2N receivers, so that the adjacent data samples are measurements taken at adjacent locations, and said method further comprises the step of imposing time delays so that the signal is substantially in phase; and wherein the estimate of the noise power is used in recovering received data.