Maximum ratio channel equalization method of short wave (SW) multiple carrier-code division multiple access (MC-CDMA)
A MC-CDMA and channel equalization technology, which is applied in the shaping network, electrical components, transmission system and other directions in the transmitter/receiver, can solve the problems of noise amplification and achieve good bit error rate performance
Active Publication Date: 2011-06-29
PLA UNIV OF SCI & TECH
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[0003] The purpose of the present invention is to provide a maximum ratio channel equalization method applied to short-wave MC-CDMA, which solves the problem of noise amplification in MC-CDMA, and simultaneously combines despreading to obtain channel equalization suitable for MC-CDMA
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[0026] Such as figure 2 As shown, first assume that the direct spreading code is an m-sequence, and the generating polynomial is: g(x)=1+x 3 +x 10 , m sequence length 1023 (0, 0, 0, 0, 0, 0, 0, 0, 0, 1, ... slightly ..., 1, 0, 0, 0, 0, 0, 0, 1) , using the four-path and six-path models in the Waterson channel model, the channel bandwidth is 125kHz, the number of subcarriers is 1024, and each multi-carrier symbol transmits 10 bits of information. Different equalization methods include: no equalization; traditional equalization method; phase-only equalization method; static MRC equalization based on channel model and parameters obtained from long-term shortwave channel forecast; dynamic MRC equalization based on real-time channel estimation. The specific implementation process of the MC-CDMA system based on maximum ratio channel equalization is as follows:
[0027] a. Select a data frame to be sent and divide it into a group of 10 bits. According to the difference of each gr...
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The invention relates to a maximum ratio channel equalization method of short wave (SW) multiple carrier-code division multiple access (MC-CDMA), which comprises the following steps: firstly, mapping data frames to be sent in a displacement mapping module into cyclic shift with original direct sequences, and delivering the cyclic shift which is subjected to serial-to-parallel conversion to inverse fast Fourier transform (IFFT) so as to be changed into time domain modulating signals; carrying out serial-to-parallel conversion on modulated parallel time domain signals, inserting pilot frequency symbols into the obtained parallel time domain signals after serial-to-parallel conversion, and sending the obtained parallel time domain signals in which the pilot frequency symbols are inserted to a receiving end by a channel; after the signals which are received by the receiving end and comprise the pilot frequency symbols and the data frames are subjected to the serial-to-parallel conversion, firstly sending to fast Fourier transform (FFT) and then evaluating the transmission functions of the SW channel by the received pilot frequency symbols; obtaining equilibrium factors of maximal ratio combining efficiency (MRCE) through the data frames received by the receiving end in accordance with the evaluated the transmission functions of the channel, and then carrying out the maximum ratio channel equalization; and carrying out correlation on each sub-carrier datum subjected to the maximum ratio equalization and sequences generated by local spreading codes, obtaining dispreading data by judgment, and receiving the next data frame by a receiver continuously. The maximum ratio channel equalization method has a preferable bit error ratio and is used to reach an anti-interference effect.
Description
technical field [0001] The invention belongs to the technical field of communication anti-interference, in particular to a maximum ratio channel equalization method of short-wave MC-CDMA. Background technique [0002] Due to the influence of multipath on the shortwave channel, the data transmission rate has been low and unstable. Can utilize multi-carrier and code division multiple access technology to transmit reliable high-speed data (Jan E M N, Timothy C G.Widebandmulti-carrier transmission for military HF communications[C].Proc.Milcom'97, Monterey, U.S.A.1997.1046 -1051.), an advantage is to use simple frequency domain equalization to compensate for the unevenness of the channel. The traditional channel equalization method is to divide the frequency domain received signal by the frequency domain response of the channel transfer function at the receiving end. However, since the transfer function of the multipath channel has a relatively low point (deep fading) in the fre...
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IPC IPC(8): H04L25/03H04B1/711
Inventor 王金龙阚春荣沈良王呈贵盛雁鸣童晓兵
Owner PLA UNIV OF SCI & TECH
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