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Message-driven frequency hopping: Design and analysis

This paper considers spectrally efficient frequency hopping (FH) system design. Relying on time-frequency diversity over large spectrum, FH systems are robust against hostile jamming interference. However, the spectral efficiency of existing FH systems is very low due to inappropriate use of the total available bandwidth. To improve the system capacity, in this paper, we propose an innovative message-driven frequency hopping (MDFH) scheme. Unlike in traditional FH where the hopping pattern of each user is determined by a pre-selected pseudo-random (PN) sequence, inMDFH, part of the message stream will be acting as the PN sequence, and transmitted through hopping frequency control. As a result, system efficiency is increased significantly since additional information transmission is achieved at no extra cost on either bandwidth or power. We further enhance MDFH by allowing simultaneous transmissions over multiple frequency bands. The enhanced MDFH scheme, named E-MDFH, can achieve high spectral efficiency, and can readily be extended to an FH-based collision-free multiple access scheme. Quantitative performance analysis on the proposed schemes demonstrates that: transmission through hopping frequency control essentially introduces another dimension to the signal space, and the corresponding coding gain can increase the system efficiency by multiple times.