Layered space-time nonlinear precoding method in multi-carrier code division multiple access (MC-CDMA) system

A code division multiple access and precoding technology, which is applied in the field of spatial multiplexing layered space-time transmission of multiple-input multiple-output multi-carrier systems, and can solve problems such as the decoding complexity of the error layer transmission effect.

Inactive Publication Date: 2010-10-06
HENAN UNIVERSITY OF TECHNOLOGY
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Problems solved by technology

[0006] The purpose of the present invention is to provide a layered space-time nonlinear precoding method in a multi-carrier code division multiple access system to solve the error-layer transmission effect and translation effect of the traditional detection of the vertical layered space-time scheme in the MIMO-MC-CDMA system. The problem of high code complexity

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  • Layered space-time nonlinear precoding method in multi-carrier code division multiple access (MC-CDMA) system
  • Layered space-time nonlinear precoding method in multi-carrier code division multiple access (MC-CDMA) system
  • Layered space-time nonlinear precoding method in multi-carrier code division multiple access (MC-CDMA) system

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[0031] 1. System model

[0032] VBLAST-MC-CDMA precoding system model such as figure 1 As shown, assume that the total number of users is U, the number of transmitting antennas is N, and the number of receiving antennas is M ( ). At the transmitter, each user data is processed by VBLAST mapping, encoding, etc. to form N-layer parallel data, and then spread spectrum to form data on each layer, and then perform serial-to-parallel transformation, IFFT transformation, and looping on each layer of data prefix, perform precoding, and modulate to each transmitting antenna by parallel variable serial modulation. At the receiving end, serial-to-parallel conversion, cyclic prefix removal, FFT, etc. are reversed for each received signal. In this way, the frequency-selective multipath fading channel is transformed into Nc flat-fading sub-channels, and the despread signal of the u-th user of all M receiving antennas on the k-th subcarrier can be expressed as:

[0033] (1)

[0...

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Abstract

The invention relates to a layered space-time nonlinear precoding method in a multi-carrier code division multiple access (MC-CDMA) system. The method comprises the following steps of: firstly, establishing a precoding system; adopting geometric mean resolution on feedback channel information in the system to form a product of a unitary matrix and an upper triangular matrix to obtain a precoding matrix with the same equivalent noise gain; carrying out nonlinear modular algebra precoding (THP, Tomlinson-Harashima Precoding) among MC-CDMA subcarrier channels at the transmitting end; multiplying all subcarrier signals after carrying out THP and the unitary matrix obtained by channel geometric mean resolution and then transmitting from a corresponding antenna; and processing at the receiving end by adopting a Zero Forcing (ZF) criterion or a minimum mean-squared error (MMSE) criterion. The method effectively eliminates the layer mistaking transmission effect of a layered space-time code, improves the code mistaking performance of the system, reduces the complexity of a downlink receiver and can effectively resist the selective fading of channel frequency, thereby improving the transmission performance of the system.

Description

technical field [0001] The invention relates to a layered space-time nonlinear precoding method in a multi-carrier code division multiple access system, and belongs to the technical field of multi-input multi-output multi-carrier system space multiplexing layered space-time transmission. Background technique [0002] The generalized multiple-input multiple-output MIMO technology involves a wide range, mainly including transmit diversity technology and space multiplexing technology. Among them, spatial multiplexing technology is to transmit different information on different antennas. The V-BLAST code of Bell Labs is a typical application of spatial multiplexing technology; while transmit diversity technology is to transmit signals containing the same information on different antennas. So as to achieve the effect of space diversity. Space-time coding technology based on transmit diversity has attracted much attention because it combines transmit diversity in the space domain...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L1/00
Inventor 傅洪亮陶勇张德贤张元杨铁军梁义涛樊超李红岩
Owner HENAN UNIVERSITY OF TECHNOLOGY
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