A comparison of unfiltered and filtered complex spreading sequences based on aperiodic correlation properties

This paper presents an overview and comparison of some of the known families of polyphase sequences for direct sequence spread spectrum multiple access (DS/SSMA) communication systems. A comparison between Zadoff and Chu (Frank and Zadoff 1962; Chu 1972) (ZC), Opperman and Vucetic (1997) (OV), and constant-envelope root-of-unity (CE-RU) filtered generalized chirp-like sequences is presented including the special class of analytical bandlimited complex (ABC) spreading sequences. The comparison is based on aperiodic correlation characteristics rather than traditionally discussed parameters like periodic, even, and odd correlations. The emphasis is based on practical considerations rather than rigorous mathematical derivation as found in literature. This paper is unique in the sense that it also presents the effects of filtering on polyphase sequences by using proper filtering methods.