【摘要】：隨著向信息化社會(huì)的邁進(jìn),移動(dòng)互聯(lián)網(wǎng)時(shí)代的到來,衛(wèi)星通信的應(yīng)用范圍正在得到不斷地?cái)U(kuò)展。目前,以互聯(lián)網(wǎng)、大數(shù)據(jù)為代表的新一代信息技術(shù)正在迅猛的發(fā)展。衛(wèi)星通信系統(tǒng)作為重要的通信基礎(chǔ)設(shè)施,需積極應(yīng)對(duì)信息技術(shù)領(lǐng)域的這一發(fā)展方向。然而,面對(duì)物聯(lián)網(wǎng)“萬物互聯(lián)”的需求,基于傳統(tǒng)互聯(lián)網(wǎng)業(yè)務(wù)的寬帶多媒體衛(wèi)星通信系統(tǒng)將難以滿足如此大量的接入需求。因此,需要對(duì)衛(wèi)星的多址接入問題展開進(jìn)一步的研究,用以在有限的頻譜資源內(nèi)滿足盡可能多的物聯(lián)網(wǎng)信息節(jié)點(diǎn)的聯(lián)網(wǎng)接入要求。大量的科研結(jié)果已經(jīng)證明大規(guī)模天線技術(shù)不僅可以提供比MIMO(Multiple-Input,Multiple-Output)系統(tǒng)更高的頻譜利用率,而且可以提高系統(tǒng)的容量和信道的可靠性,并且簡(jiǎn)單的線性檢測(cè)即可達(dá)到最優(yōu)的性能。隨著陣列天線技術(shù)的日漸成熟,目前已在衛(wèi)星通信上得到越來越多的應(yīng)用�；谛l(wèi)星具有陣列天線及大規(guī)模天線系統(tǒng)具有上述優(yōu)勢(shì)的事實(shí),衛(wèi)星通信可以通過將大規(guī)模MIMO系統(tǒng)的技術(shù)應(yīng)用于陣列天線系統(tǒng)來有效地支持海量網(wǎng)絡(luò)信息節(jié)點(diǎn)的接入,這與傳統(tǒng)的多波束空分多址接入(SDMA)不同。衛(wèi)星通信信道區(qū)別于地面通信信道最重要的特征之一是接收信號(hào)中有較強(qiáng)的直射分量的存在。本文針對(duì)布置了等距型陣列天線的衛(wèi)星通信上行系統(tǒng),首先驗(yàn)證了其信道向量的漸進(jìn)正交性�；诖苏恍�,提出了適用于此系統(tǒng)的解碼方法,并假設(shè)其信道狀態(tài)信息(CSI)已知的情況下,推導(dǎo)出了其最大可達(dá)速率及其對(duì)應(yīng)的一個(gè)下界。在這些公式的基礎(chǔ)上,首先分析所提出的最大比合并(MRC)解碼法和最小均方誤差(MMSE)解碼法的解碼性能。然后比較衛(wèi)星通信系統(tǒng)采用MRC檢測(cè)和MMSE檢測(cè)之后的可達(dá)速率,及其對(duì)應(yīng)下界的比較。通過仿真驗(yàn)證了提出的解碼方法的可行性,并且MMSE解碼法的解碼性能要比MRC解碼法好很多,但相應(yīng)的計(jì)算復(fù)雜度要高些;相同條件下,MMSE檢測(cè)的可達(dá)速率要比MRC檢測(cè)的高。仿真證實(shí)了以上結(jié)果。實(shí)際情況下,信道狀態(tài)信息(CSI)一般是未知的,為此就要進(jìn)行信道的估計(jì)。準(zhǔn)確的估計(jì)出信道信息對(duì)系統(tǒng)的解碼性能有重要的影響。在本文中,提出了幾種新的信道估計(jì)方法,并詳細(xì)分析了所提出的信道估計(jì)方法的原理。通過與傳統(tǒng)MMSE信道估計(jì)方法的仿真比較,驗(yàn)證了所提估計(jì)方法的優(yōu)越性。
[Abstract]:With the development of information society and the arrival of mobile Internet, the application of satellite communication is expanding. At present, the new generation of information technology, represented by the Internet and big data, is developing rapidly. As an important communication infrastructure, satellite communication system should actively deal with this development direction in the field of information technology. However, in the face of the "interconnection of everything" in the Internet of things, the broadband multimedia satellite communication system based on traditional Internet services will be difficult to meet the needs of such a large number of access. Therefore, it is necessary to further study the multiple access problem of satellites in order to meet the requirements of as many Internet of things information nodes as possible in the limited spectrum resources. A large number of scientific results have proved that the large-scale antenna technology can not only provide higher spectral efficiency than MIMO (Multiple-Input,Multiple-Output) system, but also improve the system capacity and channel reliability, and simple linear detection can achieve the optimal performance. With the development of antenna array technology, more and more applications have been made in satellite communication. Based on the fact that satellite has the advantages of array antenna and large-scale antenna system, satellite communication can effectively support the access of massive network information nodes by applying the technology of large-scale MIMO system to array antenna system. This is different from the traditional multiple beam space division multiple access (SDMA). One of the most important characteristics of satellite communication channel is the existence of strong direct-emitting component in the received signal. In this paper, the asymptotic orthogonality of channel vectors is verified for the uplink system of satellite communication with equidistant array antennas. Based on this orthogonality, a decoding method suitable for this system is proposed, and its maximum reachable rate and its corresponding lower bound are derived under the assumption that the channel state information (CSI) is known. Based on these formulas, the decoding performance of the maximum ratio combined (MRC) decoding method and the minimum mean square error (MMSE) decoding method is first analyzed. Then, the reachability rate of satellite communication system using MRC detection and MMSE detection is compared, and the corresponding lower bound is compared. The feasibility of the proposed decoding method is verified by simulation, and the decoding performance of the MMSE decoding method is much better than that of the MRC decoding method, but the corresponding computational complexity is higher, and the reachable rate of the MMSE detection is higher than that of the MRC detection under the same conditions. Simulation results confirm the above results. In practice, channel state information (CSI) is generally unknown, so channel estimation is necessary. Accurate estimation of channel information has an important impact on the decoding performance of the system. In this paper, several new channel estimation methods are proposed, and the principle of the proposed channel estimation methods is analyzed in detail. Compared with the traditional MMSE channel estimation method, the superiority of the proposed method is verified.
【學(xué)位授予單位】：杭州電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN927.2

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本文編號(hào)：2249824