本文選題：SDN + 邊緣網(wǎng)絡(luò)�。� 參考：《電子科技大學(xué)》2017年碩士論文

【摘要】：隨著車聯(lián)網(wǎng)、智慧城市、虛擬現(xiàn)實等新型網(wǎng)絡(luò)應(yīng)用的興起,邊緣無線網(wǎng)絡(luò)中的服務(wù)類型不斷增多。不同服務(wù)對時延的要求各不相同,從而給邊緣緩存技術(shù)帶來了新的挑戰(zhàn)。本論文基于軟件定義網(wǎng)絡(luò)(SDN)來構(gòu)建一種面向低時延的邊緣無線網(wǎng)絡(luò)緩存系統(tǒng),旨在減少用戶的訪問時延和下載時延。其中,訪問時延是指用戶訪問存儲有所需內(nèi)容的節(jié)點(diǎn)需要花費(fèi)的時間,該時延主要由內(nèi)容的存儲位置來決定;下載時延則表示內(nèi)容從緩存節(jié)點(diǎn)傳輸回用戶需要的時間,該時延主要由與用戶關(guān)聯(lián)的基站所能提供的最大傳輸速率(即吞吐量)來決定。因此,本文主要圍繞用戶關(guān)聯(lián)和緩存決策兩個方面進(jìn)行研究。(1)基于負(fù)載均衡的關(guān)聯(lián)決策模型。傳統(tǒng)的基于RSSI的關(guān)聯(lián)決策,用戶僅從自身角度出發(fā)選擇基站進(jìn)行關(guān)聯(lián),并未考慮基站的負(fù)載以及網(wǎng)絡(luò)的整體性能,這無疑會降低網(wǎng)絡(luò)的系統(tǒng)吞吐量,增加用戶的平均下載時延。因此,關(guān)聯(lián)決策不僅需要保證基站負(fù)載的相對均衡,還需要從無線網(wǎng)絡(luò)的整體出發(fā),最大化系統(tǒng)吞吐量�；谠撃繕�(biāo),本文提出了基于負(fù)載均衡的關(guān)聯(lián)決策模型。然而,隨著網(wǎng)絡(luò)規(guī)模的擴(kuò)大,關(guān)聯(lián)決策模型的求解難度較大。為了降低求解難度,本文提出了基于KLA的關(guān)聯(lián)算法,即通過引入圖劃分來創(chuàng)建虛擬基站。因此,用戶首先需要接入虛擬基站,隨后在各個虛擬基站內(nèi)與具體的物理基站相關(guān)聯(lián)。(2)基于網(wǎng)絡(luò)切片的緩存決策模型。邊緣無線網(wǎng)絡(luò)中通常存在多個服務(wù)提供商,不同服務(wù)提供商對訪問時延的要求各不相同。因此,緩存決策需要在保證不同服務(wù)提供商對訪問時延要求的同時,減少網(wǎng)絡(luò)內(nèi)用戶的平均訪問時延,從而提高用戶體驗。基于該目標(biāo),本文通過引入網(wǎng)絡(luò)切片對緩存資源進(jìn)行虛擬化,來滿足不同服務(wù)的訪問時延要求,并提出了基于網(wǎng)絡(luò)切片的緩存決策模型。同時,本文證明了緩存決策模型具備NP完全性,并針對緩存決策模型的特點(diǎn)設(shè)計出了一種啟發(fā)式算法來求解�；谏鲜龅难芯績�(nèi)容,本文還進(jìn)行了大量的仿真來驗證評估基于負(fù)載均衡的關(guān)聯(lián)決策模型和基于網(wǎng)絡(luò)切片的緩存決策模型各方面的性能。最后,本文使用車載無線服務(wù)器對整個緩存系統(tǒng)進(jìn)行了原型驗證。
[Abstract]:With the rise of new network applications, such as car networking, intelligent city, virtual reality, the types of services in edge wireless networks are increasing. Different services have different requirements for delay, which brings new challenges to edge caching technology. Based on the software definition of SDN, this paper constructs a low delay oriented edge wireless network cache system, which aims to reduce the user's access delay and download delay. Among them, the access delay refers to the time spent by the user to access the node with the required content, which is mainly determined by the storage location of the content, while the download delay indicates the time that the content is transferred back to the user from the cached node. The delay is mainly determined by the maximum transmission rate (i.e. throughput) that the base station associated with the user can provide. Therefore, this paper focuses on two aspects: user association and cache decision. In the traditional association decision based on RSSI, the user chooses the base station to associate only from its own point of view, without considering the load of the base station and the overall performance of the network, which will undoubtedly reduce the system throughput of the network and increase the average download delay of the user. Therefore, the association decision not only needs to ensure the relative balance of the base station load, but also needs to maximize the system throughput from the wireless network as a whole. Based on this goal, this paper presents a load-balancing-based decision-making model. However, with the expansion of network scale, it is difficult to solve the associated decision model. In order to reduce the difficulty of solving the problem, this paper proposes an association algorithm based on KLA, which is to create virtual base station by introducing graph partition. Therefore, the user needs to access the virtual base station first, and then associate with the physical base station in each virtual base station. There are usually multiple service providers in edge wireless networks. Different service providers have different requirements for access delay. Therefore, cache decision-making needs to reduce the average access delay of users in the network while ensuring that different service providers require access delay, so as to improve the user experience. Based on this goal, this paper introduces network slicing to virtualize cache resources to meet the access delay requirements of different services, and proposes a cache decision model based on network slicing. At the same time, this paper proves that the cache decision model has NP completeness, and designs a heuristic algorithm to solve the problem according to the characteristics of the cache decision model. Based on the above research, a large number of simulations are carried out to verify and evaluate the performance of the load balancing based decision model and the cache decision model based on network slicing. Finally, this paper uses the vehicle wireless server to verify the whole buffer system prototype.
【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】：2017
【分類號】：TN915.0

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本文編號：1791322