Design of an Adaptive Multiresolution $M$ -Ary DCSK System
Multiresolution $M$ -ary differential chaos shift keying (MR- $M$ -DCSK) system enables unequal-priority transmission via exploiting non-uniformly spaced phase constellations. In this letter, an adaptive MR- $M$ -DCSK system is proposed by using a new constellation parameter design. Aiming at maximizing the spectral efficiency, the constellation parameter is carefully selected based on signal-to-noise ratio, and then is further optimized by a new search algorithm. Both the analytical and simulation results show that the proposed adaptive MR- $M$ -DCSK system not only can enhance the spectral efficiency as compared with the adaptive $M$ -DCSK system, but can satisfy different bit-error-rate requirements for different bits within a symbol as well.