Design And Analysis Of High Throughput Differential Chaos Shift Keying Communication Systems

By 2020,the Internet of Things(IoT)will grow exponentially.As one of the key technologies of the IoT,the short-range wireless communication technology based on the 5th generation(5G)wireless networks is to achieve high-throughput with low-power consumption in green communications.Recently,the chaotic ultra-wideband(UWB)technology has been widely concerned about,and it has been included in some Institute of Electrical and Electronics Engineers(IEEE)standards.Therefore,it is significant to study key technology of high-throughput differential chaotic shift keying(DCSK)systems.In this paper,the transmitter and receiver of high-throughput DCSK systems are designed and analyzed,and the coverage of the DCSK based UWB systems is researched.The main work of the dissertation includes the following aspects:(1)The M-ary DCSK system is one of the classic Multi-dimensional modulation systems based on Walsh code.However,the bandwidth of M-ary DCSK system grows exponentially as the number of transmitted bits increases.To solve the problem,in this paper,a multilevel code-shifted DCSK(MCS-DCSK)system with rate adaptive is proposed where the Walsh code is used for multiplexing.The complexity of MCS-DCSK system is greatly reduced and the bandwidth efficiency is greatly improved.In addition,under the same bandwidth efficiency,the bit error rate(BER)performance of MCS-DCSK system is better than that of M-ary DCSK system.Finally,the BER performance of MCS-DCSK system is analyzed by employing Gaussian approximation(GA)method,and the feasibility of the system is verified by simulations.(2)To further improve the throughput of DCSK system,a multi-carrier chaotic shift keying system(MM-DCSK)combining orthogonal frequency division multiplexing(OFDM)with chaotic modulation is proposed,where subcarrier correlation is employed and two-dimensional constellation mapping is used.By employing the high correlation between adjacent subcarriers,the chaotic reference signal and the information signal are palced in adjacent subcarriers,respectively.Thus,the energy efficiency is greatly increased compared with conventional DCSK system.In addition,the time diversity is achieved.Finally,the PAPR performance of MM-DCSK system is researched,and a simple PAPR reduction algorithm is proposed.Simulation results show that the proposed algorithm can effectively reduces the PAPR.(3)Driven by incresing demand for indoor transmision,a transmitted-reference multi-carrier differential chaotic shift keying(MC-MDCSK)system is proposed,where the orthogonal chaotic signals are used as basis functions for two-dimensional constellation mapping.The simulated results show that the frequency diversity is obtained,and the system performance is insensitive to the length of the cyclic prefix(CP).Then the coverage of FM MC-MDCSK UWB system over IEEE.802.15.4a standard channel is analyzed.It is shown that by extending the chaotic pulse duration the coverage of the system can be improved.Finally,there is an optimal bandwidth for a specific BER performance in the system.