M-ary code shift keying (MCSK) is combined with differential chaos shift keying (DCSK) for low-rate UWB communications. The combined M-ary code shift (MCS)/DCSK shifts the reference-information signal pair to the location determined by (log2 M)-bit data, hence transmitting a (1 + log 2M)-bit symbol for the duration of one bit transmitted using DCSK, which in turn can be used to increase the silent periods within and between transmitted signal pairs. The resulting signaling format improves the bit error probability (BEP) performance of DCSK-based systems without altering the receiver structure or increasing the computational complexity, and provides longer silent periods to combat the worse effects of multipath (MP) fading. These results can be used to improve the ranging and location capability of DCSK-based low-rate ultra wideband (UWB) communication systems.