Evaluation of pseudonoise sequence in time spread pulse position modulation/code division multiple access systems
Toshitaka Date, Xuping Zhou, Ikuo Oka, Chikato Fujiwara · Electronics and Communications in Japan (Part I Communications) · 1996
Abstract To evaluate the processing gain performance of the binary maximal‐length sequence (m sequence), the Gold sequence and the Kasami sequence in a time spread pulse position modulation/code division multiple access (PPM/ CDMA) system, the merit factors of these sequences are calculated and a lower bound on the processing gain of a time spreading filter is derived using the merit factors. It is shown that, under the condition that the sequence length is large, the merit factor of the m sequence approaches 3, the merit factors of the Gold sequence and the Kasami sequence approach 1, the m sequence having the strongest impulse noise resistibility. Furthermore, the cross merit factor between two pseudonoise sequences is defined as a parameter expressing the capability of suppressing multiple access interference. It is shown that the cross merit factors of m sequences, synchronous Gold sequences, and good synchronous Kasami sequences approach 3, and the cross merit factor of bad synchronous Kasami sequence having the strongest multiple access interference suppression capability and the bad synchronous Kasami sequence having almost no multiple access interference suppression capability.