Direct sequence spread spectrum transmission process, with generation and optimization of sequences

A method for communicating information via direct sequence spread spectrum transmission, comprising steps of:

• transmitting a transmitted signal, including substeps of
• producing pseudo-random sequences of elements belong to an M.sup.th set of roots of unity with a higher throughput than that for data to be transmitted, said pseudo-random sequences of elements being a set of N random sequences of elements each having a given length L,
• optimizing respective of the N random sequences of elements according to respective self-correlation and inter-correlation function of the elements by minimizing both of the following two quantities, ##EQU13## where u is an integer for all pairs of (X,Y) sequences in the set of N random sequences of elements, X and Y being two different sequences, and ##EQU14## where u is an integer not congruous to 0 modulo L for all X sequences in the set of N random sequences of elements, cas being equal to respective possible values of elements belonging to the M.sup.th set of roots of unity,
• assigning respective of the set of N random sequences after said optimizing step to each user and producing another set of optimized sequences for use by each user if conditions for using the method change,
• multiplying data provided by each user by the sequence assigned to that user,
• modulating a radio wave carrier with the set of N random sequences assigned in said assigning step after being multiplied with the data in said multiplying step, and
• transmitting the radio wave carrier after said modulating step as said transmitted signal;
• and
• receiving the transmitted signal, including substeps of
• receiving the transmitted signal, where the transmitted signal includes large amplitude peaks, referred to as principle peaks and smaller amplitude peaks, referred to as secondary peaks,
• filtering the transmitted signal by sequence according to the set of N random sequences assigned to each user,
• detecting values of the data starting from the principles peaks after said filtering step, and
• restoring the data included in the transmitted signal based on the values detected in the detecting step.