Relatively prime length spreading sequences for DS-CDMA

In this paper we present three sets of spreading sequences, each of which consists of seven real-valued, quasiorthogonal spreading sequences, of lengths 16, 31, and 63, which are relatively prime. The spreading sequences are numerically obtained and their properties are evaluated in terms of even and odd cross-correlation functions. It is shown that the cross-correlation functions of the spreading sequences with relatively prime lengths take small values uniformly and that the bit-error rate of synchronous uplink direct-sequence code-division multiple access is little affected by the cross-correlation.