論文基于fpga的mc一cdma基帶系統(tǒng)的實(shí)現(xiàn)-全文預(yù)覽
【正文】 越高則能夠承載的比特越多，傳輸?shù)念l帶利用率越高，但是調(diào)制的階數(shù)越高抗干擾性能越差。LEN端口用于選擇產(chǎn)生的數(shù)據(jù)長(zhǎng)度為該最短長(zhǎng)度的倍數(shù)，在長(zhǎng)度為T*LEN長(zhǎng)度的隨機(jī)序列內(nèi)該信號(hào)為高電平。圖3為該8級(jí)帶反饋的移位寄存器的結(jié)構(gòu)圖圖4為使用Modalism得到的功能仿真結(jié)果，其中， RESET為復(fù)位信號(hào)，高電平有效，OE為信號(hào)發(fā)生使能信號(hào)，只有OE為高電平時(shí)，才啟動(dòng)信號(hào)產(chǎn)生程序。從圖中可以看出，實(shí)現(xiàn)MC一CDMA調(diào)制的功能，需要三個(gè)二級(jí)子模塊，其中有兩個(gè)二級(jí)子模塊又各自調(diào)用了一個(gè)三級(jí)子模塊。時(shí)鐘和時(shí)序控制模塊:clk一anagertx()在調(diào)制、MC一CDMA調(diào)制模塊中都涉及到數(shù)據(jù)的串并變換或者復(fù)制操作，將導(dǎo)致不同模塊的控制時(shí)鐘發(fā)生變化，對(duì)應(yīng)于每種調(diào)制方式的基帶系統(tǒng)都需要四種不同的時(shí)鐘來(lái)控制，當(dāng)系統(tǒng)支持三種調(diào)制方式時(shí)，就要六種時(shí)鐘。調(diào)制模塊:qam64()/qaml6()/PS()實(shí)現(xiàn)將信源模塊產(chǎn)生的隨機(jī)比特序列映射為數(shù)字基帶符號(hào)的功能，本文中設(shè)計(jì)了QPsK、16QAM和64QAM三種調(diào)制方式。發(fā)射機(jī)的實(shí)現(xiàn)設(shè)計(jì)分為五個(gè)功能模塊:信源模塊，調(diào)制模塊，編碼模塊，MC一CDMA調(diào)制模塊，時(shí)鐘和時(shí)序控制模塊。本文在接收機(jī)檢測(cè)算法的設(shè)計(jì)方面，為了達(dá)到降低系統(tǒng)實(shí)現(xiàn)復(fù)雜度，提高系統(tǒng)實(shí)用價(jià)值的目的，優(yōu)先考慮了采用低實(shí)現(xiàn)復(fù)雜度的ZF檢測(cè)算法，選取了Grevllfe分塊算法作為ZF檢測(cè)中的矩陣求逆方法。將自適應(yīng)調(diào)制技術(shù)引入空域復(fù)用MOMC一CDMA系統(tǒng)能夠充分利用無(wú)線信道容量，更有效地提高信息傳輸速率。對(duì)本文的研究工作做出重要貢獻(xiàn)的個(gè)人和集體，均已在文中以明確方式注明。據(jù)本人所知，論文中除已注明部分外不包含他人已發(fā)表或撰寫過(guò)的研究成果。M0MC技術(shù)在提高系統(tǒng)頻譜利用率方面性能卓越，多載波CDMA技術(shù)則能有效地對(duì)抗頻率選擇性衰落，將MIMO技術(shù)與MC一CDMA方案相結(jié)合，構(gòu)成空域復(fù)用MC一CDMA系統(tǒng)，將在很大程度上提高系統(tǒng)的性能和容量。在MC一CDMA調(diào)制的實(shí)現(xiàn)方面，借用了OVSF碼的產(chǎn)生方法來(lái)實(shí)現(xiàn)Walsh碼的產(chǎn)生，可配置產(chǎn)生32種不同的擴(kuò)頻碼字。關(guān)鍵詞:MIMO，MC一CDMA，基帶系統(tǒng)，F(xiàn)PGA分類號(hào): ABSTRACTABSTRACT:MIMO,multicatrier and linkadaptive Inodulation techniques are a few key kinds of physical layer techniqucs infuture wireless munication mission technique have a excellent performance in promoting spectral efficiencies, multicatrier and CDMA tcchniquc can alleviate the frcqucy一sclective fading effect effectively. Combinating MIMO technique and MC一CDMA scheme into MIMO MC一CDMA system will improve the performance and capacity of a mobile munications the adaptive modulation technique into MIMO MC一CDMA system can take full advantage of wireless channcl capacity,and improve data rates more effectively.The work fulfillish the study of adaptive cross layer wireless transmission Technology in FPGA Implementation of MC一CDMA task 15 to plete the design and implementation of a FPGA一based basebandsignal Processing Platform for FPGA Implementation of一CDMA Base一band System.The work in this paper contains the design and implementation of a generic modem supporting QPSK,16QAM and 64QAM modulation modes, the design and implementation of a VBALSTcodec,the design and implementation of a MC一CDMA modem, the design and implementation of ZF VBLAST directional goritllln,the design all implelnentation of the clock management module crossing six clock domains, at last achieved the final structure of the digital base一band transceiver for a airspace multiplexing MI MOMC一CDMAsystem.In the design of the generic modem, considng the realization of demodulator perfonnance and plexity, different demodulation methods were designed based on the modulation with the different constellation mapping characteristics. The realization of the MC一CDMA modem,used the method of generating OVSF code to Generate the code,and32 kinds of spreading codes can be configured for different characteristics.In order to reduce the system plexity, increase the system practical value, ZFdetection algorithm was adopted because of its low implementation plexity. The Goreville block algorithm was selected as a matrix inversion method in ZF detection. In the Profess of the realization，make full use of hardware approaches for basic puting，eonlbined with various the soft IPcoreand the characteristics of FPGA chips，reasonable Planned matrix inversion，matrix multiplication Operations，achieved a receiver detection algorithm with a consumption resources.This Paper use a hardware’s emulation model for MIMO channel to achieve the Joint debugging and functional verification，and pared with the software simulation results obtained a good Perform
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