A Multiple-Access Time and Frequency Spectrum-Spreading Modulation

In this paper a novel modulation scheme called Carrier Interleaved Multiple Access (CIMA) is proposed. CIMA provides an alternative for multiple-access modulation accommodating resistance to noise and channel interference. The approach is based on polar signaling modulated with an FM-like composite sinusoidal function. The user assigned frequency deviation and modulation index are strictly related and unique. The latter parameters are generated using a nontraditional pseudorandom noise generator (PRNG). This PRNG provides CIMA with low interference capability between cochannels and adjacent channels. CIMA can be considered for a single-user or multiple-access technique. Selected CIMA characteristics are presented. In order to numerically illustrate the effectiveness of the proposed modulation scheme, the performance of CIMA is compared with the conventional direct-sequence spread spectrum binary phase-shift keying (DSSS-BPSK) modulation.