A method for reducing ICI of OFDM system by using transfer pre-coding

A neutron and channel technology, which is applied in the field of wireless transmission preprocessing, can solve the problems of receiver complexity at the receiving end, reduce frequency utilization and bandwidth, and achieve the effects of reducing complexity, improving bit error rate, and reducing ICI interference

Inactive Publication Date: 2008-05-28
SHENZHEN TINNO MOBILE TECH CO LTD
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Problems solved by technology

ICI self-cancellation method is an effective ICI cancellation method, but this method reduces frequency utilization and bandwidth
The coding / transformation method designs a matrix / transformation through an algebraic method to obtain a large coding gain and diversity gain for the signal, so that part of the interference caused by multipath fading can be tolerated, but the receiver at the receiving end becomes quite complicated

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  • A method for reducing ICI of OFDM system by using transfer pre-coding
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  • A method for reducing ICI of OFDM system by using transfer pre-coding

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Embodiment Construction

[0011] Due to the time-varying nature of the channel and the phase noise between the transmitter and receiver, frequency deviation may be caused. The deviation of carrier frequency will cause the orthogonality between subcarriers to be destroyed, resulting in subcarrier interference ICI. It will have a very serious impact on system performance. In order to overcome the above-mentioned influence, the present invention adopts a transmission zero-forcing precoding method for the signal at the sending end, performs transmission precoding processing on the signal to be sent, and eliminates subcarrier interference. The above process specifically includes the following steps:

[0012] At the sending end, a finite impulse response FIR channel is transformed into a convolution matrix channel H according to the cyclic prefix of the OFDM system; the sending end control processor invokes the formula H'=F H HF, by FFT transformation matrix F, IFFT transformation matrix F H Perform FFT tr...

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Abstract

The invention relates to a method for reducing ICI in an OFDM system by utilizing precode transmission. Because of the time variability of an actual channel and the phase noise between a sender and a receiver, frequency departure is possibly caused, the departure of the carrier frequency can cause the damage to the orthogonality among sub carriers, therefore inter carrier interference (ICI) is generated. Through predetermining the demodulation algorithm of the receiving terminal, the invention adopts a zero forcing principle to construct a modulation matrix M, a sending signal is preprocessed through the modulation matrix, the channel influence is counteracted in advance at the sending terminal, therefore the effect of reducing the ICI is achieved. By adopting the method of the invention, not only bit error rate is greatly improved, but also the complexity of the OFDM system receiver is reduced, thereby the invention is especially suitable for the down chain of a TDD system.

Description

technical field [0001] The present invention relates to wireless communication technology, in particular to wireless transmission preprocessing technology. Background technique [0002] OFDM systems are more sensitive to carrier frequency offset than single-carrier systems. Due to the time-varying nature of the channel and the phase noise between the transmitter and receiver, frequency deviations may occur. The offset of the carrier frequency will cause orthogonality between subcarriers. The performance is destroyed, resulting in subcarrier interference ICI, if no measures are taken to overcome the ICI, it will have a very serious impact on system performance. [0003] At present, the methods for reducing ICI mainly include frequency domain equalization method, time domain equalization method, time domain windowing method, ICI self-elimination method, encoding / transformation method, etc. The frequency domain equalization method uses the pilot signal and the training sequenc...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L25/03
Inventor 谢显中姜琳琳
Owner SHENZHEN TINNO MOBILE TECH CO LTD
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