An M-ary spread spectrum receiver based on orthogonal cyclic codes

This paper proposes a novel M-ary spread spectrum receiver scheme based on time-frequency transform domain. At the transmitter of the system, the M spreading codes of each user are generated by circularly shifting the prototype spreading code. At the receiver, a time-frequency transform domain orthogonal matched-filter is employed to noncoherently dispread and demodulate the received signals. The proposed scheme reduces computation and spreading codes selection difficulty of M-ary spread spectrum system remarkably. The BER performances of the receiver for single user and multiuser are analyzed, and the computations for three kinds of M-ary dispreading methods are compared. The results show that the proposed scheme has better BER performance and lower computation complexity than that of traditional M-ary systems.