Abstract
In this work, a generalized form of Spreading-Code-Phase-Shift-Keying (SCPSK) modulation is proposed. The performance of M-SCPSK modulation with coherent receiver in an AWGN channel exposed to multi-user interference is investigated. Two types of M-ary SCPSK modulation-one employing short spreading codes and the other employing long spreading codes - are examined and the union bounds of symbol error probabilities are derived. Additionally, feasible designs of the M-CPSK transmitter and receiver are proposed. The M-SCPSK system with long spreading codes employed is found to be more flexible and therefore more suitable for packet data service applications.