Area Spectral Efficiency of Soft-Decision Space–Time–Frequency Shift-Keying-Aided Slow-Frequency-Hopping Multiple Access

Space-Time FSK for Slow Frequency-Hopping Multiple Access

Amplitude Shift Keying & Frequency Shift Keying

Aim: To generate and demodulate an amplitude shift keyed (ASK) signal and a binary FSK signal. Amplitude shift keying-ASK-in the context of digital communications is a modulation process, which imparts to a sinusoid two or more discrete amplitude levels. These are related to the number of levels adopted by the digital message. For a binary message sequence there are two levels, one of which is ...

A novel frequency-hopping spread-spectrum multiple-access network using M-ary orthogonal Walsh sequence keying

A novel frequency-hop spread-spectrum multiple-access network employing -ary orthogonal Walsh sequence keying with noncoherent demodulation is proposed. The transmitted Walsh sequence is overlaid by a user-specific pseudonoise sequence to reduce the effect of multiple-access hits. Two Gaussian approximations for the multiple-access interference from both the dehopped slot and its neighboring sl...

A multiple access technique for differential chaos shift keying

Various chaos-based digital communications techniques have been proposed recently. Among them, differential chaos shift keying (DCSK) allows the receiving end to decode the signal using noncoherent detection. This paper proposes and analyses a multiple access scheme for DCSK. A simple 1-dimensional iterative map has been used to generate the chaotic signals for all users. Bit error probabilitie...

Overlapping -ary Frequency Shift Keying Spread-Spectrum Multiple-Access Systems Using Random Signature Sequences

In this paper, a multiple-access spread-spectrum communication system using binary frequency shift keying (BFSK) or M -ary frequency shift keying (MFSK) and noncoherent demodulation is considered. In contrast to previous work typically assuming that the frequency shift keying (FSK) tones are nonoverlapping after direct-sequence (DS) spreading, here we consider a spread-spectrum multiple-access ...