發(fā)布時(shí)間：2018-02-13 12:53

  本文關(guān)鍵詞： 認(rèn)知無線電 資源分配 頻譜聚合 標(biāo)記值 NC-OFDM　出處：《電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：移動互聯(lián)網(wǎng)飛速發(fā)展的顯著特點(diǎn)是無線新業(yè)務(wù)的高速增長和用戶需求的不斷增加,隨之帶來諸多關(guān)鍵技術(shù)問題亟需解決,例如如何提升頻譜利用率;有效地與周圍環(huán)境交互并從中獲取信息進(jìn)行學(xué)習(xí)以及做出決策;通過自適應(yīng)調(diào)整實(shí)現(xiàn)無線電的智能化等。認(rèn)知無線電系統(tǒng)具備主動感知、智能學(xué)習(xí)、動態(tài)調(diào)整和決策等能力,能夠充分優(yōu)化無線資源配置,提高頻譜利用效率,提供高質(zhì)量和多樣化的應(yīng)用,也為解決上述問題提供了有效的途徑。但其仍面臨著如頻譜感知、頻譜接入與動態(tài)管理、功率控制、自適應(yīng)傳輸?shù)汝P(guān)鍵技術(shù)的挑戰(zhàn),也正是由于這些技術(shù)需求才將它與傳統(tǒng)的無線電技術(shù)區(qū)分開。因此,本論文的研究內(nèi)容為認(rèn)知網(wǎng)絡(luò)中頻譜分配的問題。本文采用了認(rèn)知網(wǎng)絡(luò)中頻譜分配問題研究中常用的圖著色模型。為了解決集中式頻譜分配復(fù)雜度高的問題,論文中采取了頻譜聚合技術(shù),以聚合后的空閑子載波集合為單位進(jìn)行資源分配,這樣可以有效降低分配算法的復(fù)雜度。但隨之而來的問題是頻譜利用率的降低,為此論文又采用快速注水功率分配算法對聚合后的集合中的子載波進(jìn)行功率優(yōu)化,從而提高系統(tǒng)頻譜利用率。在此基礎(chǔ)上,本文提出了C-Sum算法,仿真結(jié)果表明這種基于頻譜聚合的頻率與功率聯(lián)合分配算法可以兼顧運(yùn)算復(fù)雜度和頻譜利用效率。在對分布式資源分配問題的研究中,論文以已有文獻(xiàn)中的三種分布式頻譜分配算法為基礎(chǔ),考慮各節(jié)點(diǎn)在同一信道下增益不同時(shí)的場景,針對原有算法的缺陷提出了兩種改進(jìn)的分布式算法,即M-Greedy算法和M-Fair算法。M-Greedy和M-Fair算法根據(jù)各節(jié)點(diǎn)的標(biāo)記值大小進(jìn)行決策,標(biāo)記值的定義中考慮了各節(jié)點(diǎn)之間的協(xié)作。仿真結(jié)果表明改進(jìn)后的算法在公平性與頻譜利用率性能上有較大提升,尤其是M-Fair算法,能夠更好的兼顧頻譜利用效率和各用戶之間的公平性。論文最后又利用Simulink設(shè)計(jì)了NC-OFDM鏈路,其目的是通過對認(rèn)知無線網(wǎng)絡(luò)中認(rèn)知用戶隨著授權(quán)用戶的子載波占用情況的變化采取動態(tài)避讓決策過程進(jìn)行動態(tài)演示,從而進(jìn)一步理解NC-OFDM原理并對以后的研究提供參考價(jià)值。
[Abstract]:The rapid development of mobile Internet is characterized by the rapid growth of new wireless services and the increasing demand of users, which brings a lot of key technical problems to be solved, such as how to improve the spectrum efficiency; The cognitive radio system has the ability of active perception, intelligent learning, dynamic adjustment and decision making. It can fully optimize the allocation of wireless resources, improve the efficiency of spectrum utilization, provide high-quality and diversified applications, and provide an effective way to solve the above problems, but it still faces such problems as spectrum sensing, spectrum access and dynamic management. The challenges of key technologies such as power control, adaptive transmission, and so on, are precisely due to these technical requirements to distinguish it from the traditional radio technology. In this paper, the problem of spectrum allocation in cognitive networks is discussed. In order to solve the problem of high complexity of centralized spectrum allocation, this paper adopts the graph coloring model which is commonly used in the research of spectrum allocation in cognitive networks. In this paper, spectrum aggregation technology is adopted to allocate resources in units of aggregate free subcarriers, which can effectively reduce the complexity of the allocation algorithm, but the following problem is the reduction of spectrum efficiency. In order to improve the spectrum efficiency of the system, this paper uses the fast water injection power allocation algorithm to optimize the power of the subcarriers in the aggregated set. On the basis of this, the C-Sum algorithm is proposed in this paper. The simulation results show that the combined frequency and power allocation algorithm based on spectrum aggregation can take into account the computational complexity and spectrum utilization efficiency. Based on three kinds of distributed spectrum allocation algorithms in previous literatures and considering the different gain of each node in the same channel, two improved distributed algorithms are proposed to overcome the shortcomings of the original algorithms. That is, M-greedy algorithm and M-Fair algorithm. M-Greedy and M-Fair algorithm make decision based on the value of each node. In the definition of label value, the cooperation among the nodes is considered. The simulation results show that the improved algorithm improves the performance of fairness and spectrum efficiency greatly, especially M-Fair algorithm. It can better balance spectrum efficiency and fairness among users. Finally, the NC-OFDM link is designed by using Simulink. The purpose of this paper is to make a dynamic demonstration of cognitive users in cognitive wireless networks with the change of subcarrier occupancy of authorized users, so as to further understand the principle of NC-OFDM and provide reference value for future research.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN925

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 廖楚林;陳R，

本文編號：1508207