Recent spreading codes for spread spectrum communication systems

This paper presents recent spreading codes and their applications to spread spectrum (SS) systems. First, co-channel interference in spread spectrum multiple access communication systems (SSMA) and cross-correlation functions are described, and the relationship between new “No sequences” with low cross-correlations and other well known sequences is summarized. Second, an SSMA using very low-rate convolutional codes proposed by Viterbi is described. With this SSMA the spectral efficiency can be improved over that of FDMA using a guardband. Finally, optical orthogonal codes for fiber networks, orthogonal Gold sequences, orthogonal Bent sequences for synchronous SSMA, majority logic combination sequences using M-sequences, and generalized Geffe sequences for rapid acquisition are described.