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Wavelet transformation-based hybrid carrier modulation method and system

A wavelet transform and hybrid carrier technology, applied in the direction of phase modulation carrier system, baseband system, baseband system components, etc., can solve the problem of ISI being difficult to eliminate, destroy the orthogonality of sub-carriers, etc., and achieve the effect of reducing the impact

Active Publication Date: 2017-03-08
GUILIN UNIV OF ELECTRONIC TECH
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AI Technical Summary

Problems solved by technology

Single-carrier systems are not affected by ICI, but ISI caused by multipath propagation is difficult to eliminate, that is, single-carrier modulation systems are easily affected by ISI
Orthogonal frequency division multiplexing technology under the DS channel, the Doppler frequency shift destroys the orthogonality between the subcarriers, so there is a serious ICI

Method used

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  • Wavelet transformation-based hybrid carrier modulation method and system
  • Wavelet transformation-based hybrid carrier modulation method and system
  • Wavelet transformation-based hybrid carrier modulation method and system

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Embodiment Construction

[0043] The principle of mixed carrier modulation based on wavelet transform is as follows:

[0044] For any complex sequence D of length N 0 =[d 0 d 1 ... d N-1 ], its weighted fractional wavelet transform can be defined as:

[0045] n a [D]=W a D (1)

[0046] where the weighting matrix W a for:

[0047] W a =A(a+2)I N +A(a+1)F+A(a)PI N +A(a-1)PF (2)

[0048] In the formula, A(a) is a weighting coefficient, A(a)=cos(aπ / 4)cos(aπ / 2)exp(3ajπ / 4); the value of the modulation parameter a is -2≤a≤-1. I N Is an N*N identity matrix, F is a discrete wavelet transform matrix, P is a permutation matrix, P ij =δ( N ), where the dimension of P is determined by the dimension of the input signal, N is a modulo operation. The expression of P is as follows:

[0049]

[0050] The formula (1) is described by the physical block diagram as figure 1 shown. Input a set of serial data with a length of N, which is divided into 4 branches after serial-to-parallel conversion. The ...

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Abstract

The invention discloses a wavelet transformation-based hybrid carrier modulation method and system. According to the method and system of the invention, the wavelet transformation-based hybrid carrier modulation method is adopted to suppress ISI(inter symbol interference) / ICI(inter carrier interference) under a doubly-selective channel; the modulation characteristics of wavelet transformation and single-variable carriers are integrated, so that SC (single-carrier) and MC (multi-carrier) modulated signals can be simultaneously transmitted, and therefore, the free rotation of the signals in a time-frequency domain plane can be successfully achieved; multi-carrier components are very sensitive to ICI generated by Doppler frequency shift, and ISI caused by delay spread will exert great influence on single-carrier components, while, by means of changing modulation parameters, influence to the system caused by the two kinds of interference can be effectively reduced.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a wavelet transform-based mixed carrier modulation method and system. Background technique [0002] The wireless channel exhibits a double dispersion characteristic in a high-speed mobile environment, that is, double selective fading (DS: DoublySelective fading). The communication quality of the communication system under this channel will be affected by the following two aspects, one is the inter-symbol interference (ISI: Inter Symbol Interference) caused by the multipath delay, and the other is the subcarrier interference caused by the Doppler effect. Inter Carrier Interference (ICI: Inter Carrier Interference), how to effectively suppress these two kinds of interference and improve the communication performance of the system is a problem that must be solved in communication. [0003] Currently, single-carrier (SC: Single-Carrier) modulation technology and multi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/20H04L27/22H04L25/03
CPCH04L25/03006H04L25/03343H04L25/03821H04L27/20H04L27/22H04L2025/03401
Inventor 谢跃雷郑兆飞万杰李永强
Owner GUILIN UNIV OF ELECTRONIC TECH
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