車載通信的聯合速率調整與功率控制技術研究

藉由車載通信強化駕駛體驗是非常吸引人且必然的未來趨勢，合作式的先進駕駛輔助系統(co-ADAS)藉由車輛之間的資訊交換可以因此更加促進道路安全和效率。然而多數的相關研究關注在不同車輛密度之下輕量安全封包的傳送。很少有相關研究同時考慮大量資料通訊和嚴格的延遲限制。因此，在此篇論文中，我們關注大量資料通訊，並且採用連續的封包傳送通訊當作一個嚴峻的檢驗標準來涵蓋各種車載應用。我們考慮調速機制在車載通信環境下支援加權公平性針對安全封包或非安全封包。此外，我們考慮功率控制對封包傳輸實際在車載網路通信下會遇到的問題，並提出一個新的功率控制策略應對。我們提出一個演算法藉由隨機最佳控制(stochastic optimal control)來對應在車載網路通信下的各種不確定因素。首先，我們利用指數成本函數(exponential cost function)去進一步地縮減信號與干擾加噪聲比和端到端延遲的最小化。另外，考量即時決策的需求在快速變化的車載網路下，我們利用外部輸入(exogenous inputs)支援隨時的功率控制和調速機制的條件比較。透過電腦模擬結果顯示，我們提出的演算法優於在靜態隨意網路下同樣考慮嚴格延遲限制的方法。我們可以達到相似的效能當干擾變多時，但只花費一半不到的功率節省大約 61 毫瓦和 57 毫瓦。在周圍沒有其餘的使用者情境下，封包抵達率可以高於 12.11% 且花費較少的傳輸功率。我們的方法消耗適當的功率，可以達到更高的封包抵達率和更低的封包延遲率。此外，在車輛密度上升時會降低傳送的功率，此趨勢和多數的車載功率控制方法相同。

關鍵字

車載通信；速率調整；功率控制；隨機最佳控制

並列摘要

The tendency towards the usage of vehicular communications to enhance driving experiences is attractive and inevitable, and thus the cooperative advanced driver assistance system (co-ADAS) is able to promote the road safety and efficiency by exchanging the information of traffic among some of the vehicles. The majority of related work focus on transmission of the light safety message under different vehicle density. There are a few works discuss on heavy data communications with stringent latency constraints. In this thesis, we focus on the heavy data communications, and even adopt continuous packet transmission as a serious criterion to cover diverse vehicular applications. We consider the rate adaptation, which supports weighted fairness for safety or non-safety messages, designed for vehicular environments. Moreover, we take into account practical problems encountered when utilizing the power control for the packet transmission in VANET, and a new power control strategy is proposed. In order to address the presence of various uncertainties in VANET, we propose an algorithm based on stochastic optimal control techniques. The more sensitive exponential cost function is used to further minimize the SINR deviation and also end-to-end delay. For instant decisions, the exogenous inputs support comparison of conditions for power control and rate adaptation at any time. Evaluation results show that the proposed algorithm outperforms the method considering delay minimization in static ad hoc networks. We can achieve the similar performance while interference increases but only consume less than half power saving about 61 mW and 57 mW. The delivery ratio is higher 12.11% but consumes less power while no neighboring pair. The proposed method consumes the appropriate power and achieves the higher packet delivery and the lower packet delay ratio. Besides, the power consumption is decreasing while vehicle density increases, which is suitable for VANET.

並列關鍵字

VANET ； rate adaptation ； power control ； stochastic optimal control

參考文獻

[2] N. Lu, N. Cheng, N. Zhang, X. Shen, and J. W. Mark, “Connected vehicles: Solutions and challenges,” IEEE Internet of Things Journal, vol. 1, no. 4, pp. 289–299, Aug 2014.

[4] G. Karagiannis, O. Altintas, E. Ekici, G. Heijenk, B. Jarupan, K. Lin, and T. Weil, “Vehicular networking: A survey and tutorial on requirements, architectures, challenges, standards and solutions,” IEEE Communications Surveys Tutorials, vol. 13, no. 4, pp. 584–616, Fourth 2011.

[5] A. Vinel, “3GPP LTE versus IEEE 802.11p/WAVE: Which technology is able to support cooperative vehicular safety applications?” IEEE Wireless Communications Letters, vol. 1, no. 2, pp. 125–128, April 2012.

[7] Y. L. Morgan, “Notes on DSRC & WAVE standards suite: Its architecture, design, and characteristics,” IEEE Communications Surveys Tutorials, vol. 12, no. 4, pp. 504–518, Fourth 2010.

[8] B. van Arem, C. J. G. van Driel, and R. Visser, “The impact of cooperative adaptive cruise control on traffic-flow characteristics,” IEEE Transactions on Intelligent Transportation Systems, vol. 7, no. 4, pp. 429–436, Dec 2006.

國際替代計量

車載通信的聯合速率調整與功率控制技術研究

全文下載

主題瀏覽