【摘要】：無(wú)線頻譜是一種不可再生的寶貴資源。提高頻譜資源的利用率以滿足無(wú)線通信業(yè)務(wù)的需求,是無(wú)線通信領(lǐng)域一個(gè)永恒的話題。采用認(rèn)知無(wú)線電技術(shù)實(shí)現(xiàn)認(rèn)知用戶在信號(hào)的時(shí)域、頻域和空域共享授權(quán)頻譜資源已經(jīng)成為研究熱點(diǎn),而在信號(hào)的極化域?qū)崿F(xiàn)對(duì)授權(quán)頻譜的共享卻尚未得到充分的研究。在對(duì)傳統(tǒng)時(shí)、頻、空域頻譜機(jī)會(huì)充分開發(fā)利用的基礎(chǔ)上,進(jìn)一步挖掘信號(hào)極化域上存在的頻譜資源潛力,可以使得認(rèn)知用戶與授權(quán)用戶在相同的頻段上、相同的時(shí)間內(nèi)以及相同的空間資源上共存,從而進(jìn)一步提高頻譜利用率。基于極化信息處理的認(rèn)知無(wú)線電頻譜共享技術(shù)的研究將為開發(fā)新的頻譜機(jī)會(huì)以緩解頻譜資源緊缺現(xiàn)狀開辟新的途徑。 論文選題來(lái)源于國(guó)家自然科學(xué)基金項(xiàng)目“極化域頻譜感知理論與技術(shù)研究”(項(xiàng)目編號(hào)：60902047)、國(guó)家重大科技專項(xiàng)項(xiàng)目"TD-LTE系統(tǒng)中認(rèn)知無(wú)線電技術(shù)的研究與驗(yàn)證(項(xiàng)目編號(hào)：2012ZX03003006)”。論文主要圍繞如何利用信號(hào)的極化域信息實(shí)現(xiàn)認(rèn)知用戶對(duì)授權(quán)頻譜的共享展開研究,主要研究工作及成果如下： (1)對(duì)認(rèn)知無(wú)線電頻譜共享技術(shù)和極化信息處理技術(shù)進(jìn)行了綜述和分析。歸納了現(xiàn)有研究中的頻譜共享方式并重點(diǎn)分析了認(rèn)知用戶可接入的多域頻譜機(jī)會(huì)；梳理了極化信號(hào)處理的研究現(xiàn)狀,進(jìn)而分析了在信號(hào)極化域?qū)崿F(xiàn)頻譜共享的可行性。 (2)在一對(duì)認(rèn)知用戶與一對(duì)授權(quán)用戶共存的頻譜共享方面,目前的頻譜共享算法僅能利用時(shí)域和空域的頻譜機(jī)會(huì)而導(dǎo)致對(duì)頻譜效率的提升幅度不高。針對(duì)這一問題,提出了以干擾約束和半盲極化適配為特征的變極化算法,來(lái)實(shí)現(xiàn)認(rèn)知用戶和授權(quán)用戶的同時(shí)同頻同空間共存。首先,從不妨礙授權(quán)用戶正常通信的角度出發(fā),設(shè)計(jì)了基于干擾約束的極化域頻譜共享算法。進(jìn)一步地,考慮認(rèn)知用戶難以獲取信道先驗(yàn)信息的情況,提出了基于半盲極化適配的極化域頻譜共享算法。理論和仿真分析表明,與傳統(tǒng)基于頻譜感知的時(shí)域頻譜共享算法相比,基于干擾約束和半盲極化適配的頻譜共享算法能取得更高的頻譜效率。 (3)在多對(duì)認(rèn)知用戶與一對(duì)授權(quán)用戶共存的頻譜共享方面,針對(duì)由于認(rèn)知用戶增加而導(dǎo)致的復(fù)雜干擾問題,在利用信號(hào)極化維度資源的基礎(chǔ)上進(jìn)一步利用信號(hào)空域維度的資源,提出了聯(lián)合變極化和波束賦形算法,來(lái)消除認(rèn)知用戶與授權(quán)用戶之間、認(rèn)知用戶與認(rèn)知用戶之間的干擾。為適應(yīng)多對(duì)認(rèn)知用戶與授權(quán)用戶共存場(chǎng)景所特有的授權(quán)頻譜動(dòng)態(tài)特性,設(shè)計(jì)了融合授權(quán)頻譜所有狀態(tài)的認(rèn)知用戶吞吐量?jī)?yōu)化模型。分析和仿真結(jié)果表明,論文所提出的極化-空域頻譜共享算法不僅對(duì)動(dòng)態(tài)變化的授權(quán)頻譜環(huán)境具有魯棒性,而且比傳統(tǒng)頻譜共享算法對(duì)頻譜效率的提升幅度更大。 (4)針對(duì)極化模式色散作用使得極化狀態(tài)發(fā)生色散而降低認(rèn)知用戶和授權(quán)用戶接收性能的問題,提出了在更窄的頻帶上承載極化狀態(tài)的子載波分簇機(jī)制。子載波簇的大小不僅會(huì)影響到極化模式色散作用,也會(huì)影響到認(rèn)知用戶環(huán)境學(xué)習(xí)開銷,而極化模式色散和環(huán)境學(xué)習(xí)開銷又最終影響到認(rèn)知用戶的有效吞吐量。因此設(shè)計(jì)了以最大化認(rèn)知用戶有效吞吐量為目標(biāo)的約束優(yōu)化問題并求解。仿真結(jié)果表明,通過對(duì)子載波進(jìn)行分簇,可以很好地兼顧認(rèn)知用戶環(huán)境學(xué)習(xí)開銷和避免極化模式色散影響兩方面的性能,從而在提高認(rèn)知用戶有效吞吐量的基礎(chǔ)上改善了對(duì)授權(quán)頻譜的利用。
[Abstract]:Wireless spectrum is a kind of non-renewable precious resource. It is an eternal topic in wireless communication field to improve the utilization ratio of spectrum resources to meet the needs of wireless communication services. However, the sharing of authorized spectrum in polarization domain has not been fully studied. On the basis of fully exploiting and utilizing the traditional time-frequency and space-domain spectrum opportunities, further tapping the potential spectrum resources in polarization domain can make cognitive users and authorized users in the same frequency band, the same time and the same time. Coexistence of spatial resources will further improve the spectral efficiency. The research of spectrum sharing in cognitive radio based on polarization information processing will open up a new way to develop new spectrum opportunities to alleviate the shortage of spectrum resources.
The selected topic of this paper is from the National Natural Science Foundation project "Polarization Domain Spectrum Sensing Theory and Technology Research" (Project Number: 60902047), and the major national science and technology project "Research and Verification of Cognitive Radio Technology in TD-LTE System" (Project Number: 2012 ZX03003006). To achieve cognitive user sharing of authorized spectrum, the main research work and achievements are as follows:
(1) The spectrum sharing technology and polarization information processing technology in cognitive radio are summarized and analyzed. The spectrum sharing methods in existing research are summarized and the multi-domain spectrum opportunities accessible by cognitive users are analyzed emphatically. Sex.
(2) For spectrum sharing between a pair of cognitive users and a pair of authorized users, the current spectrum sharing algorithm can only take advantage of spectrum opportunities in time and space domains, which leads to a low enhancement of spectrum efficiency. First of all, a polarization domain spectrum sharing algorithm based on interference constraints is designed from the point of view of not interfering with the normal communication of authorized users. Furthermore, considering that it is difficult for cognitive users to obtain channel prior information, a polarization domain spectrum sharing algorithm based on semi-blind polarization adaptation is proposed. Theoretical and simulation results show that the spectrum sharing algorithm based on interference constraints and semi-blind polarization adaptation can achieve higher spectrum efficiency than the traditional spectrum sensing based time domain spectrum sharing algorithm.
(3) For the spectrum sharing of multiple pairs of cognitive users and one pair of authorized users, aiming at the complex interference caused by the increase of cognitive users, a joint variable polarization and beamforming algorithm is proposed to eliminate cognitive users and authorization based on the use of signal polarization dimension resources and the use of signal spatial dimension resources. A throughput optimization model for cognitive users is designed to accommodate the unique dynamic characteristics of authorized spectrum in the scenario where multiple pairs of cognitive users and authorized users coexist. The proposed method is not only robust to the dynamic authorized spectrum environment, but also more efficient than the traditional spectrum sharing algorithm.
(4) Aiming at the problem that polarization mode dispersion causes polarization state dispersion and reduces the reception performance of cognitive users and authorized users, a subcarrier clustering mechanism is proposed to support polarization state in narrower frequency band. Therefore, a constrained optimization problem with the objective of maximizing the effective throughput of cognitive users is designed and solved. The simulation results show that the learning cost and avoidance of cognitive users can be well balanced by clustering subcarriers. Polarization-free mode dispersion affects both aspects of performance, thus improving the utilization of authorized spectrum on the basis of improving the effective throughput of cognitive users.
【學(xué)位授予單位】：北京郵電大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN92

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本文編號(hào)：2228501