Punctured Bent Function Sequences for Watermarked DS-CDMA
Minkyu Song, Gangsan Kim, Hong‐Yeop Song, Ki Won Song · IEEE Communications Letters · 2019
In this letter, we investigate the effect of inserting some randomly generated watermarking chips into known spreading sequences in terms of periodic correlations; moreover, we give two design criteria for good watermarked sequences in the sense of: 1) reducing the average correlation value and 2) minimizing the variance of correlations. For n = 2mwith even m, we propose a set of 2m-1punctured bent function sequences of length 2n-1punctured by the Singer difference set. The maximum non-trivial correlation magnitude of the proposed set turns out to be 2m+ 1, which is asymptotically two times the Welch bound.