Very high efficiency Differential Chaos Shift Keying system with Walsh Hadamard codes

摘要

In this paper an enhanced version of DCSK (Differential Chaos Shift Keying) and HE-DCSK (High Efficiency Differential Chaos Shift Keying) named Very High Efficiency Differential Chaos Shift Keying system-Walsh Hadamard (VHE-DCSK-WH) is proposed. In this new system, we use N Walsh Hadamard (WH) codes to multiplex N different data bits. A single chaotic code is also used to ensure data spreading. As in DCSK, the first time slot carries the chaotic sequence. The sum of all spreaded bits is then transmitted in the second time slot of the frame. This offers our system a bandwidth efficiency N times greater than that of DCSK system. Bit error rate (BER) analytical expression are in good agreement with simulations and shows that our system outperforms DCSK and HE-DCSK systems for N=2 and for any Eb/N0.