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Multi-ary differential chaotic shift keying modem modulated by fused code subscript

A modem and shift keying technology, applied in the modulation carrier system, multi-carrier system, phase-modulated carrier system, etc., can solve the problems of difficulty in broadband transmission, low transmission data rate and energy efficiency, etc., to improve the transmission data. rate, increase the transmission data rate, eliminate the effect of the delay circuit

Inactive Publication Date: 2019-06-07
XIAMEN UNIV
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Problems solved by technology

[0005] The purpose of the present invention is to solve the problems that the existing differential chaotic shift keying modem does not carry information for half a symbol period, which leads to the low transmission data rate and energy efficiency of the system, and the difficulty in realizing broadband transmission, etc. The multi-ary system differential chaotic shift keying modem modulated by the fusion code subscript modulation using the delay unit and improving the transmission data rate of the system at the same time

Method used

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  • Multi-ary differential chaotic shift keying modem modulated by fused code subscript
  • Multi-ary differential chaotic shift keying modem modulated by fused code subscript
  • Multi-ary differential chaotic shift keying modem modulated by fused code subscript

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Embodiment approach

[0050] If the chaotic carrier is generated by discrete Logistic mapping, the sampling frequency of the signal is set to f s =1000 times / s, the duration of the symbol is T=0.08s, then the equivalent spreading factor is defined as β=T×f s =80. The Logistic mapping equation for generating chaotic signals is When the initial value is given x(0), through the iterative formula x(i+1)=1-2×x 2 (i), i=0,....,i,....,β-1, can generate a chaotic carrier sequence with a length of β (spreading factor β) The construction method of n-order Walsh code is w n =[w n-1 w n-1 ;w n-1 -w n-1 ], P represents the code length of the Walsh code, satisfying P=2 n .

[0051] According to the chaotic carrier sequence generated above, the modulator consists of figure 2 The modulator shown performs the modulation, and its transmitted signal in each symbol period can be expressed by the following formula as

[0052]

[0053] where E s Indicates symbol energy, spreading factor SF=β, {x i ,i=...

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Abstract

The invention provides a fusion code index-modulated multi-ary differential chaos shift keying modem and relates to the field of wireless communication, wherein a receiver is free of any delay unit. Meanwhile, the fusion code index-modulated multi-ary differential chaos shift keying modem improves the system transmission data rate. The subscript value of a Walsh code is adopted as a carrier for the transmission of information bits, so that the number of bits transmitted by the system is improved. The transmission data rate and the energy efficiency of the system are improved effectively. In the orthogonal code multiplexing manner, delay units are effectively eliminated, and the complexity of system implementation is lowered. The simulations of AWGN channels and multi-path rayleigh fading channels show that, compared with the conventional DCSK, the fusion code index-modulated multi-ary DCSK system has certain performance advantages.

Description

technical field [0001] The invention relates to wireless communication, in particular to a multi-ary system differential chaotic shift keying modem modulated by fusion code subscripts. Background technique [0002] Chaotic signal is not only easy to generate, but also has low cost. It has the characteristics of broadband, aperiodic and noise-like, which makes the chaotic communication system with chaotic signal as the carrier become a low-cost alternative to the traditional spread spectrum communication system. At the same time, chaotic communication also has strong competitiveness in secure communication, short-distance communication and ultra-wideband communication systems. Differential Chaotic Shift Keying (DCSK: Differential Chaotic Shift Keying), as a kind of chaotic communication system, has the advantages of general chaotic communication system. And the DCSK system has a very simple receiver structure, and has good performance in multipath fading channels and time-va...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/00H04L27/20H04L27/22H04L27/36
CPCH04L27/001H04L27/20H04L27/22H04L27/362
Inventor 谭云生徐位凯王琳洪少华
Owner XIAMEN UNIV
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