Unlock instant, AI-driven research and patent intelligence for your innovation.

Lattice shaped decoding demodulator and demodulation method based on circulating prefix single carrier system

A cyclic prefix and demodulator technology, applied in multi-carrier systems and other directions, can solve the problems of increased noise at the output end of the equalizer, poor performance, and deterioration of demodulation performance.

Inactive Publication Date: 2008-12-03
CHONGQING UNIV OF POSTS & TELECOMM
View PDF6 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for frequency-selective fading channels, especially for channels with spectral nulls, demodulators based on frequency-domain equalization techniques will perform poorly
This is because, for frequency-selective fading channels, especially for channels with spectral nulls, frequency domain equalization will sharply amplify the noise in the deep fading spectrum part of the received signal, but the signal in this spectrum part is already very weak after channel fading. In fact, the noise at the output of the equalizer is greatly enhanced, resulting in a serious deterioration of the demodulation performance

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Lattice shaped decoding demodulator and demodulation method based on circulating prefix single carrier system
  • Lattice shaped decoding demodulator and demodulation method based on circulating prefix single carrier system
  • Lattice shaped decoding demodulator and demodulation method based on circulating prefix single carrier system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0015] The ideal detector to realize SC-CP signal is a demodulator using maximum likelihood sequence decoding algorithm. Due to the limitation of receiver implementation complexity, it is unrealistic to directly use the maximum likelihood sequence decoding method based on the exhaustive method in the actual SC-CP system (for example, use QPSK modulation constellation, select the SC-CP sequence length 16 , to realize the demodulation of an SC-CP sequence requires exhaustive enumeration of 4 16 = 2 32 sequence, such computational complexity is unacceptable in practical systems). SC-CP transmission can be expressed mathematically in the form of trellis codes, which enables the use of new modems based on trellis decoding algorithms. In the case of properly selecting the length of SC-CP sequence, the complexity of trellis decoding algorithm is completely acceptable in real-time systems. The trellis decoding algorithm is essentially a likelihood sequence decoding method, which wi...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The method uses the trellis decoded demodulator having maximum likelihood sequential decoding function to implement demodulation of SC-CP signal, there will not be a frequency domain equalization part composed of FFT, equalization and IFFT in the modem based on the trellis decoding. The modem based on the trellis decoded algorithm no loonger uses demodulation method based on frequency domain equalization structure., thus the noise increasing caused by decoder will not occur. The modem based on the trellis decoded method has better performance for the frequency selective fading channel, especially for the spectral null channel.

Description

technical field [0001] The invention relates to wireless communication and wired communication with intersymbol interference channel, in particular to a demodulator and a demodulation method of a single carrier transmission system based on cyclic prefix. Background technique [0002] In 1994, H.Sari et al. proposed a cyclic prefix-based single-carrier transmission (SC- CP, single-carrier with cyclic prefix) modulation and demodulation method. This transmission method has gradually become a relatively effective technology for wireless channels to overcome frequency selective fading and wired channels to suppress inter-symbol interference (see J.Tubbax, B.Come, L.V.Perre, L.Deneire, S.Donnav and M. Engles, "OFDM versus single carrier with cyclic prefix: a system-base comparison for binary modulation", In VTC2001Fall, vol 2, pp.1115-1119, Oct.2001). In this transmission scheme, at the sending end, the source symbol sequence to be sent after multi-ary constellation mapping is ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/34
Inventor 李祥明
Owner CHONGQING UNIV OF POSTS & TELECOMM