Research Of SIMO FM-DCSK Wireless Communication Systems

Frequency-Modulated Differential Chaos Shift Keying(FM-DCSK) is an attractive scheme joining chaotic modulation with spread-spectrum property,which is simple in implementation and robust in multipath fading channels.In this paper,space diversity has been introduced into FM-DCSK and an SIMO (Single-input and Multiple-output) architecture of the FM-DCSK modulation technique is proposed.The new scheme uses multiple antennas at the receiver end to form an SIMO structure so as to obtain a diversity gain.At the same time,orthogonal Walsh functions are employed at the transmitter,with parallel sub-streams transmitted with a single antenna to help achieve a significant increase of the data rate.Simulation results demonstrate that BER level of 10^-6,the proposed SIMO FM-DCSK architecture has an outstanding bit error rate(BER) performance in contrast to the DS-VBLAST scheme.In particular,the simpler algorithm makes the proposed architecture more efficient than the DS-VBLAST scheme.Furthermore,several main channel coding or commonly called error-correcting coding schemes are introduced into the SIMO FM-DCSK communication system with different code rates and different frame lengths over multipath fading channels.It is found that,in contrast to LDPC codes and convolutional codes,Product Accumulate (PA) codes can provide outstanding bit-error rate(BER) performance improvement in the existing SIMO FM-DCSK system.Therefore,it is expected that the proposed SIMO FM-DCSK scheme,equipped with PA codes with its advantages of simple encoding and decoding structure as well as flexibly adjustable code rate,will be applied as a strong candidate to data transmission services in wireless communication systems.