The goal of the proposed research is the use of the extensive experience base of the investigator in sequence design to design and study code sequences for a code-division (spread-spectrum) multiple-access (CDMA) communication system. The primary interest is the case when four phase signalling (QPSK) is the modulation system. The distinguishing feature of the four phase case compared to the binary case is the symbol alphabet; the symbols in a four phase modulation alphabet form a ring and not a finite field. In the new design the work proceeds in a Galois ring. Relationships to previous results are developed. Understanding four phase sequences as well as as binary sequences are now understood is a long term goal.
