UHF頻段頻譜資源和認(rèn)知TD-LTE系統(tǒng)接入關(guān)鍵技術(shù)研究
發(fā)布時(shí)間：2019-02-11 07:56
【摘要】：新一代寬帶無線移動(dòng)通信網(wǎng)絡(luò)的順利發(fā)展,需要足夠?qū)挼念l譜來支持其通信的要求。作為我國擁有自主知識產(chǎn)權(quán)4G技術(shù),TD-LTE目前獲得的頻率資源不但量少,并且都在2GHz以上。在WRC07大會(huì)上,ITU通過決議將由廣播電視系統(tǒng)進(jìn)行數(shù)字化改造而釋放的數(shù)字紅利頻段(700MHz頻段和800MHz頻段)用于IMT。然而,我國的模擬電視數(shù)字化進(jìn)程進(jìn)展緩慢,這就導(dǎo)致數(shù)字紅利頻段難以分配給TD-LTE使用。相對于歐美已經(jīng)完成了數(shù)字紅利釋放的國家,我國解決TD-LTE頻率短缺、尤其是低頻頻率缺乏的需求更為急切。 近年來研究表明,認(rèn)知無線電技術(shù)通過認(rèn)知和重新配置獲得最好的可用頻譜,對已分配的頻譜資源再次利用,是緩解頻譜供需矛盾、提高頻譜利用率的有效技術(shù)手段之一,為解決該問題提供了另一種途徑。將認(rèn)知無線電技術(shù)和TD-LTE系統(tǒng)結(jié)合起來,同時(shí)研究利用UHF頻段的空閑頻率,不但有助于解決我國的頻譜短缺及管理問題,同時(shí)也有助于在目前積極發(fā)展的商用TD-LTE基礎(chǔ)上研究認(rèn)知無線電技術(shù),對新一代寬帶無線移動(dòng)通信網(wǎng)開拓新的頻譜資源有著重大意義。 本文主要進(jìn)行了兩方面的研究,一方面是數(shù)字紅利頻段的頻譜資源使用情況,另一方面是認(rèn)知TD-LTE系統(tǒng)接入的關(guān)鍵技術(shù)之一——頻譜感知算法。首先,數(shù)字紅利頻段頻譜資源使用情況研究主要針對694-806MHz頻段,選取北京五個(gè)典型地點(diǎn),根據(jù)測試地點(diǎn)、測量時(shí)間、測量設(shè)備和參數(shù)設(shè)置確定測試方案,進(jìn)行了為其一周的頻譜監(jiān)測。最后利用Matlab進(jìn)行數(shù)據(jù)處理,生成了一周頻譜占用度光譜圖和一周頻段占用度條形圖,數(shù)據(jù)處理時(shí)采用動(dòng)態(tài)門限法來區(qū)分噪聲和信號。數(shù)據(jù)處理結(jié)果表明,五個(gè)地點(diǎn)中頻譜占用度最高的密集城區(qū)也只有25.40%的信道占用,說明TV頻段比較適合作為認(rèn)知無線電的候選頻段接入。 其次,本文結(jié)合廣播數(shù)字電視信號的特征,以經(jīng)典頻譜感知算法為基礎(chǔ),提出了優(yōu)化的基于OFDM信號的多循環(huán)頻率協(xié)作頻譜感知算法。該算法的主要思想是,利用循環(huán)特征檢測,生成單循環(huán)頻率的判決結(jié)果,然后結(jié)合Chair-Varshney最優(yōu)融合理論,將單點(diǎn)的循環(huán)頻率判決結(jié)果進(jìn)行融合,得到最后的判決結(jié)果。該算法既提高了頻譜感知的精確度,又降低了傳統(tǒng)協(xié)作頻譜感知的復(fù)雜度。仿真時(shí)采用蒙特卡洛模型進(jìn)行仿真。仿真結(jié)果證明,該算法的檢測性能明顯優(yōu)于單循環(huán)頻率檢測,并且在低信噪比的情況下依然能實(shí)現(xiàn)較準(zhǔn)確的頻譜檢測。
[Abstract]:The smooth development of the new generation broadband wireless mobile communication network requires a wide spectrum to support its communication requirements. As a 4G technology with independent intellectual property in our country, TD-LTE has not only a small amount of frequency resources, but also more than 2GHz. At the WRC07 conference, ITU passed a resolution to use the digital dividend bands (700MHz and 800MHz) released by the digital transformation of the radio and television system for IMT. However, the progress of analog TV digitization in China is slow, which makes it difficult to distribute the digital dividend band to TD-LTE. Compared with the countries in Europe and America where the digital dividend has been released, it is more urgent for our country to solve the shortage of TD-LTE frequency, especially the lack of low-frequency. Recent studies have shown that cognitive radio technology can obtain the best available spectrum through cognition and reconfiguration, and reuse the allocated spectrum resources, which is one of the effective technical means to alleviate the contradiction between supply and demand of spectrum and to improve spectrum efficiency. It provides another way to solve the problem. Combining cognitive radio technology with TD-LTE system, and studying the idle frequency of UHF band, it is not only helpful to solve the problem of spectrum shortage and management in our country. At the same time, it is helpful to study the cognitive radio technology on the basis of commercial TD-LTE, which is of great significance for the new generation of broadband wireless mobile communication networks to develop new spectrum resources. This paper mainly focuses on two aspects: on the one hand, the use of spectrum resources in the digital dividend band; on the other hand, the spectrum sensing algorithm, one of the key technologies of cognitive TD-LTE system access. First of all, the study on the use of spectrum resources in the digital dividend band is mainly aimed at the 694-806MHz frequency band. Five typical locations in Beijing are selected to determine the test plan according to the test site, measuring time, measuring equipment and parameter setting. The frequency spectrum is monitored for one week. Finally, Matlab is used to process the data, and a one-week spectrum chart and a one-week frequency band occupancy bar chart are generated. The dynamic threshold method is used to distinguish the noise from the signal in the data processing. The data processing results show that only 25.40% of the channel occupancy is found in the dense urban area with the highest spectrum occupancy among the five locations, which indicates that the TV band is more suitable to be used as a candidate frequency band for cognitive radio access. Secondly, based on the classical spectrum sensing algorithm, an optimized multi-cycle frequency cooperative spectrum sensing algorithm based on OFDM signal is proposed. The main idea of this algorithm is to generate the decision result of single cycle frequency by using cyclic feature detection, and then combine the optimal fusion theory of Chair-Varshney to fuse the decision result of single point cyclic frequency and get the final decision result. This algorithm not only improves the accuracy of spectrum sensing, but also reduces the complexity of traditional cooperative spectrum sensing. Monte Carlo model is used for simulation. Simulation results show that the detection performance of this algorithm is obviously better than that of single-cycle frequency detection, and it can still achieve more accurate spectrum detection under the condition of low signal-to-noise ratio (SNR).
【學(xué)位授予單位】：北京郵電大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.5
本文編號：2419542
[Abstract]:The smooth development of the new generation broadband wireless mobile communication network requires a wide spectrum to support its communication requirements. As a 4G technology with independent intellectual property in our country, TD-LTE has not only a small amount of frequency resources, but also more than 2GHz. At the WRC07 conference, ITU passed a resolution to use the digital dividend bands (700MHz and 800MHz) released by the digital transformation of the radio and television system for IMT. However, the progress of analog TV digitization in China is slow, which makes it difficult to distribute the digital dividend band to TD-LTE. Compared with the countries in Europe and America where the digital dividend has been released, it is more urgent for our country to solve the shortage of TD-LTE frequency, especially the lack of low-frequency. Recent studies have shown that cognitive radio technology can obtain the best available spectrum through cognition and reconfiguration, and reuse the allocated spectrum resources, which is one of the effective technical means to alleviate the contradiction between supply and demand of spectrum and to improve spectrum efficiency. It provides another way to solve the problem. Combining cognitive radio technology with TD-LTE system, and studying the idle frequency of UHF band, it is not only helpful to solve the problem of spectrum shortage and management in our country. At the same time, it is helpful to study the cognitive radio technology on the basis of commercial TD-LTE, which is of great significance for the new generation of broadband wireless mobile communication networks to develop new spectrum resources. This paper mainly focuses on two aspects: on the one hand, the use of spectrum resources in the digital dividend band; on the other hand, the spectrum sensing algorithm, one of the key technologies of cognitive TD-LTE system access. First of all, the study on the use of spectrum resources in the digital dividend band is mainly aimed at the 694-806MHz frequency band. Five typical locations in Beijing are selected to determine the test plan according to the test site, measuring time, measuring equipment and parameter setting. The frequency spectrum is monitored for one week. Finally, Matlab is used to process the data, and a one-week spectrum chart and a one-week frequency band occupancy bar chart are generated. The dynamic threshold method is used to distinguish the noise from the signal in the data processing. The data processing results show that only 25.40% of the channel occupancy is found in the dense urban area with the highest spectrum occupancy among the five locations, which indicates that the TV band is more suitable to be used as a candidate frequency band for cognitive radio access. Secondly, based on the classical spectrum sensing algorithm, an optimized multi-cycle frequency cooperative spectrum sensing algorithm based on OFDM signal is proposed. The main idea of this algorithm is to generate the decision result of single cycle frequency by using cyclic feature detection, and then combine the optimal fusion theory of Chair-Varshney to fuse the decision result of single point cyclic frequency and get the final decision result. This algorithm not only improves the accuracy of spectrum sensing, but also reduces the complexity of traditional cooperative spectrum sensing. Monte Carlo model is used for simulation. Simulation results show that the detection performance of this algorithm is obviously better than that of single-cycle frequency detection, and it can still achieve more accurate spectrum detection under the condition of low signal-to-noise ratio (SNR).
【學(xué)位授予單位】：北京郵電大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.5
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 黃奇珊;彭啟琮;路友榮;韓猛;;OFDM信號循環(huán)譜結(jié)構(gòu)分析[J];電子與信息學(xué)報(bào);2008年01期
2 楊小牛;;從軟件無線電到認(rèn)知無線電,走向終極無線電——無線通信發(fā)展展望[J];中國電子科學(xué)研究院學(xué)報(bào);2008年01期
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