GCI-DCSK: Generalized Carrier Index Differential Chaos Shift Keying Modulation

Abstract

A carrier index differential chaos shift keying (CI-DCSK) modulation has been proposed to improve BER performance, spectral efficiency (SE) and energy efficiency (EE) compared to traditional DCSK. CI-DCSK employs a one-to-one mapping between the index symbols and the carrier activation patterns, which limits the numbers of both index carriers and index bits. In this letter, a generalized carrier index differential chaos shift keying (GCI-DCSK) modulation is proposed, which extends the aforementioned CI-DCSK by employing the combinatorial method to index selector and index demapper, where the numbers of both index carriers and index bits are arbitrarily adjustable. Theoretical bit error rate (BER) expressions over both additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels are derived. It is shown that GCI-DCSK can flexibly provide red the desired performance, EE, and SE compared to CI-DCSK, commutation code index DCSK (CCI-DCSK) and permutation index DCSK (PI-DCSK). Besides, in some cases, GCI-DCSK can provide higher SE, larger EE and better error performance than multicarrier DCSK (MC-DCSK) with the same bandwidth.