Patent ID: 9712207
Date: 2017-07-18
CPC Classifications: H04B,H04J

Claim:
1. A method for de-spreading data signals (DS) that have been spread using a Walsh sequence (W(n,m)) of the chip lengths N, which are received as the first data stream in a periodic sequence, wherein the method comprises: splitting the first data stream into at least a second and a third non-periodic data stream, each of which comprises alternating N successive chips of the first data stream arriving with a chip cycle; with each chip cycle, computing a correlation of the lengths N for each chip sequence in the second and in the third data streams with stored sequences; determining desired signals using the second and third data streams by calculating the respective maximums of the computed correlations within 2N−1 chip cycles, and evaluating the symmetry of the calculated maximums with a threshold value; wherein determining the desired signal comprises checking the condition: and wherein: ABS=absolute value, T=predetermined threshold value, Main maximum=maximum value of the calculated correlations within 2N−1 chip cycles, a=sum of all correlation maximums within N−1 chip cycles that precede the main maximum, and b=sum of all correlation maximums within N−1 chip cycles that follow the main maximum; and joining the determined desired signals in an alternating manner, in each case following N chip cycles, for generating the de-spread first data stream.