Patent ID: 7274729

Claim:
A spread spectrum communication receiver comprising: a receiver which receives a signal using a pseudo noise code from a transmitter; and a matched filter which has taps, each tap having a weight, wherein said transmitter has a pseudo noise code generator for generating, as said pseudo noise code, a code sequence having a code length of at least 14 and having a value corresponding to a peak of one of plural absolute auto-correlation side lobes having a smallest value, which is calculated such that in a synchronous detection system, a signal code sequence Sk corresponds to 1 and 0 of an information signal and is represented by the following equation: S k = [ m mod ⁢ ⁢ ( k / n ) ⁡ ( data = 1 ⁢ ⁢ or ⁢ ⁢ 0 ) - m mod ⁢ ⁢ ( k / n ) ⁡ ( data = 0 ⁢ ⁢ or ⁢ ⁢ 1 ) ( Expression ⁢ ⁢ 1 ) wherein m j (j=1, 2, . . . , n; n=code length) corresponds to one of the pseudo noise codes b j as represented by the following equation: m j = [ 1 ⁢ ⁢ ( b j = 1 ) - 1 ⁢ ⁢ ( b j = 0 ) ( Expression ⁢ ⁢ 2 ) wherein in a delay detection system, the signal code sequence S k is represented by the following equation: S k = [ m mod ⁢ ⁢ ( k / n ) ⁢ S k - 1 ⁡ ( data = 1 ⁢ ⁢ or ⁢ ⁢ 0 ) - m mod ⁢ ⁢ ( k / n ) ⁢ S k - 1 ⁡ ( data = 0 ⁢ ⁢ or ⁢ ⁢ 1 ) ( Expression ⁢ ⁢ 3 ) wherein a reference code of a receiving side is denoted by M j , and a correlation coefficient O k is represented by the following equation: O k = ∑ j = 1 n ⁢ S k + j - 1 ⁢ M j ( Expression ⁢ ⁢ 4 ) in a case where M j =m j , and the correlation coefficient O k represents an auto-correlation coefficient which is represented by the following equation: O k = ∑ j = 1 n ⁢ S k + j - 1 ⁢ M j ( Expression ⁢ ⁢ 5 ) wherein sub-peaks other than correlation peaks (mod(k/n)≠1) are referred to as side lobes; and wherein said value of said peak of the one of the absolute auto-correlation side lobes having the smallest value refers to the highest point of said one of the absolute auto-correlation side lobes.