Research On The Reducing Of PAPR In MC-CDMA And Its Baseband Realization

The multi-carriers CDMA (MC-CDMA) is a kind of the combination of OFDM and CDMA technology. The technology uses OFDM with the CDMA system, reduces the data rate of the CDMA system, and enhances high speed data processing service ability. It is inherited from the OFDM and the CDMA technology, has the unique superiority at the high speed multimedia data transmission, has the anti-frequency selectivity ability, and can against inter symbol interrupt. It has high frequency spectrum use ration, and its modulation and demodulation may use is discrete Fourier to transform (DFT) to realize, can reduce the system complexity.The paper mainly researched the peak to average technology of the MC-CDMA system and realized the baseband design. It proposed the optimal condition of the spectrum code in the MC-CDMA system, and considered the peak value factor of spectrum code, the correlation characteristic, and the spectrum correlation characteristic. The main works include:1,Main introduced the theory and the system structure of CDMA, OFDM and the MC-CDMA. With start of analyzing the Shannon formula, introduce CDMA spread spectrum principle, OFDM technology principle and the FFT realization, analyzed three kinds of carriers CDMA. Get the result that MC-CDMA has the clearly concept, simple structure, performance, and superior against other two kind of plans.2,Researched reduce of PAPR of MC-CDMA. Discussed the PAPR issue, studied the grey supplementary sequence and the choice mapping method, did the simulation confirmation. Proposed the optimal condition of the spread spectrum code of MC-CDMA; for the grey supplementary sequence has the advantage of PAPR no bigger than 6dB and the disadvantage of bad correlation, this article uses the m sequence and the Gold sequence improves the grey supplementary sequence the performance, which computation is small and it is usable in practice.3,Realizes the MC-CDMA baseband design. Introduced the MC-CDMA baseband realizations model, introduced the DSP and the FPGA chip, selected the concrete hardware architecture, introduced the realization process, and had test and the appraisal to the system.The research indicated that uses the improvedt grey sequence can improve PAPR...