本文選題：酉空時星座圖 + 酉空時調(diào)制　； 參考：《華中科技大學(xué)》2014年碩士論文

【摘要】：多輸入多輸出（MIMO）調(diào)制技術(shù)可以提供空間分集增益和空間復(fù)用增益，它能夠有效提高頻譜利用率和信道容量，是目前4G和未來移動通信的關(guān)鍵調(diào)制技術(shù)。為了適應(yīng)在高速移動的快衰落信道通信環(huán)境，Marzetta和Hochwald提出了非相干酉空時通信系統(tǒng)，該系統(tǒng)在調(diào)制和解調(diào)過程中不需要獲取信道狀態(tài)信息（CSI），因而無需占用信道帶寬來發(fā)射導(dǎo)頻信號。通過論證得出信道容量可達(dá)的非相干酉空時發(fā)射信號矩陣具有酉矩陣結(jié)構(gòu)，Zheng等人將Grassmann流形這一數(shù)學(xué)工具引入到非相干酉空時通信的研究中，認(rèn)為酉空時星座圖的每一個星座點(diǎn)對應(yīng)于Grassmann流形上的一個點(diǎn)。 本文在國家自然科學(xué)基金項(xiàng)目“非相干MIMO通信系統(tǒng)編碼調(diào)制關(guān)鍵技術(shù)研究”的資助下，重點(diǎn)研究了基于Grassmann流形的酉空時調(diào)制解調(diào)算法，提出了對跖結(jié)構(gòu)酉空時星座圖的設(shè)計(jì)方法及對跖結(jié)構(gòu)酉空時星座圖調(diào)制的簡化解調(diào)算法。 1）本文提出Grassmann流形上的酉空時矩陣框架結(jié)構(gòu)，在該框架約束下，以Frobenius弦距離作為星座圖構(gòu)造的距離準(zhǔn)則，通過設(shè)置合適的步長來改變酉矩陣中每個元素的幅值和相位，在Grassmann流形上搜索最小Frobenius弦距離大于閾值的星座點(diǎn)，并將該星座點(diǎn)的對跖點(diǎn)也納入星座圖中，從而構(gòu)造L個星座點(diǎn)的酉空時星座圖。仿真實(shí)驗(yàn)表明，用這種次優(yōu)的搜索算法所得到的星座圖與文獻(xiàn)中已經(jīng)發(fā)表酉空時星座圖相比，具有更好的性能。 2）針對Grassmann流形上非相干酉空時調(diào)制對跖星座圖的結(jié)構(gòu)特征，提出并證明了Grassmann流形上任意一對對跖點(diǎn)之間存在確定的恒等關(guān)系，，并且在此基礎(chǔ)上提出了基于最大似然的非相干酉空時碼的簡化解調(diào)算法，仿真實(shí)驗(yàn)表明該解調(diào)算法在計(jì)算復(fù)雜度比最大似然解調(diào)算法降低一半的情況下，性能保持不變。因此，該簡化方案是一種最優(yōu)解調(diào)算法。
[Abstract]:Multi-Input-Multiple-Output (MIMO) modulation technology can provide spatial diversity gain and spatial multiplexing gain. It can effectively improve spectrum efficiency and channel capacity. It is a key modulation technology for 4G and future mobile communications. An incoherent unitary space-time communication system is proposed to adapt to fast fading channel communication environments in high-speed mobile systems, such as Marzetta and Hochwald. In the process of modulation and demodulation, the system does not need to obtain channel state information (CSI), so it does not need to take up the channel bandwidth to transmit pilot signals. It is proved that the incoherent unitary space-time transmit signal matrix with reachable channel capacity has unitary matrix structure and Zheng et al. The mathematical tool of Grassmann manifold is introduced into the study of incoherent unitary space-time communication. It is considered that every constellation point of unitary space-time constellation graph corresponds to a point on the Grassmann manifold. In this paper, a unitary space-time modulation and demodulation algorithm based on Grassmann manifold is studied, supported by the National Natural Science Foundation of China, "Research on key Technologies of coding and Modulation in incoherent MIMO Communication system". This paper presents a design method of unitary space-time constellation with metatarsal structure and a simplified demodulation algorithm for modulation of unitary space-time constellation with metatarsal structure. 1) in this paper, the unitary space-time matrix frame structure on Grassmann manifold is proposed. Under the constraint of this framework, the Frobenius chord distance is used as the distance criterion of constellation diagram, and the amplitude and phase of each element in the unitary matrix are changed by setting the appropriate step size. The constellation points whose minimum Frobenius chord distance is greater than the threshold value are searched on the Grassmann manifold, and the corresponding metatarsal points of the constellation point are also included in the constellation diagram, so as to construct the unitary space-time constellation map of L constellation points. The simulation results show that the constellation diagram obtained by the sub-optimal search algorithm has better performance than the unitary space-time constellation map published in the literature. 2) in view of the structural characteristics of non-coherent unitary space-time modulation (STM) pairs of constellations on Grassmann manifolds, a definite identity relationship between any pair of pairs of metatarsal points on Grassmann manifolds is proposed and proved. On this basis, a simplified demodulation algorithm based on maximum likelihood for incoherent unitary space-time codes is proposed. The simulation results show that the performance of the proposed demodulation algorithm remains unchanged under the condition that the computational complexity is reduced by half as compared with the maximum likelihood demodulation algorithm. Therefore, the simplified scheme is an optimal demodulation algorithm.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN919.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 彭秋平;彭立;楊玲玲;;基于Grassmann流形的非相干空時碼設(shè)計(jì)[J];電子學(xué)報(bào);2011年07期

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