臺灣博碩士論文加值系統

在車載通訊網路中，車輛可以透過路側基地台做連線，使用網際網路的服務。基地台的訊號範圍無法涵蓋所以的道路區域，使的車輛離開基地台的連線範圍時，會遭遇到網路連線中斷以及不可靠連線的情形。透過車間中繼節點傳輸可以解決基地台傳輸範圍的限制，但車載通訊網路有車輛拓樸高變動性以及無線衰弱通道環境等特性，中繼節點選擇會遭受到很大的挑戰。我們所提出中繼節點選擇方法利用機會中繼選擇的優點，當基地台要傳輸封包到目的車輛時，基地台向傳輸範圍廣播封包。當車輛成功的接收到封包，便成為候選中繼節點。能夠有較好表現的候選中繼節點應當成為中繼節點並幫忙轉送封包。我們使用通道狀態資訊來修改競爭視窗的大小，擁有較好的通道品質的候選中繼節點擁有較小的競爭視窗，因此有較大的機會可以競爭成為中繼節點。模擬結果證實使用通道狀態資訊修改競爭視窗大小可以有效的提高傳送成功率以及減少傳輸的延遲。

In a drive-thru Internet vehicular network, vehicles can communicate with access points (APs) for the Internet services. When a vehicle leaves the AP’s transmission range, it encounters intermittent connectivity and unreliable connection. Vehicle-to-vehicle (V2V) relay supports a solution that can extend the limitation of transmission coverage. However, the harsh conditions of wireless channel and the rapid change of vehicle topology remain the challenge for relay selection. We propose a method leverages the advantage of opportunistic relay. AP broadcasts the packet to its coverage, and those vehicles which successfully receive the packet become the relay candidates. The relay candidates which can give the best performance should be selected as a relay. We use the channel state information to modify the contention window size, and the relay candidate with higher quality of channel has better chance to contend as a relay. The simulation shows that the proposed method can efficiently increase the delivery ratio and decrease the transmission delay.

Chapter 1 Introduction...1
Chapter 2 Related Work...5
Chapter 3 System Model...9
3.1Network Model...9
3.2Propagation Path-loss Model...10
3.3Fading Channel...12
Chapter 4 The Proposed Method...14
4.1Channel State Information...14
4.2IEEE 802.11 Distributed Coordination Function...16
4.3Contention Relay with CSI...17
4.4Analytical model of Received Power...21
4.5Adaptive CSI-based DCF...25
Chapter 5 Simulation...26
5.1Simulation Setup...26
5.2Results...30
5.3Results of adaptive CSI-based DCF...35
Chapter 6 Conclusions...43
References...44

[1]IEEE Draft Standard for Amendment to Standard [for] Information Technology-Telecommunications and information exchange between systems-Local and Metropolitan networks-Specific requirements-Part II: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications-Amendment 6: Wireless Access in VehicularEnvironments, IEEE Std P802.11p/D11.0 April 2010, pp. 1-35, 2010.
[2]R. Uzcategui and G. Acosta-Marum, Wave: A tutorial, Communications Magazine, IEEE, vol. 47, pp. 126-133, 2009.
[3]IEEE Standard for Information Technology - Telecommunications and Information Exchange Between Systems - Local and Metropolitan Area Networks - Specific Requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, IEEE Std 802.11-2007 (Revision of IEEE Std 802.11-1999), pp. 1-1076, 2007.
[4]IEEE Standard for Information technology-- Local and metropolitan area networks-- Specific requirements-- Part 11: Wireless LAN Medium Access Control (MAC)and Physical Layer (PHY) Specifications Amendment 5: Enhancements for Higher Throughput, IEEE Std 802.11n-2009 (Amendment to IEEE Std 802.11-2007 as amended by IEEE Std 802.11k-2008, IEEE Std 802.11r-2008, IEEE Std 802.11y-2008, and IEEE Std 802.11w-2009), pp. 1-565, 2009.
[5]L. Pei, T. Zhifeng, and S. Panwar, A cooperative MAC protocol for wireless local area networks, in IEEE International Conference on Communications, 2005, pp. 2962-2968 Vol. 5.
[6]L. Pei, T. Zhifeng, N. Sathya, K. Thanasis, and S. P. Shivendra, CoopMAC: A Cooperative MAC for Wireless LANs, IEEE Journal on Selected Areas in Communications, vol. 25, pp. 340-354, 2007.
[7]Z. Ting, H. Sharif, M. Hempel, P. Mahasukhon, W. Wei, and M. Tao, A Novel Adaptive Distributed Cooperative Relaying MAC Protocol for Vehicular Networks, IEEE Journal on Selected Areas in Communications, vol. 29, pp. 72-82, 2011.
[8]Z. Jin, Z. Qian, and J. Weijia, VC-MAC: A Cooperative MAC Protocol in Vehicular Networks, IEEE Transactions on Vehicular Technology, vol. 58, pp. 1561-1571, 2009.
[9]Y. Joon, B. S. C. Choi, and M. Gerla, An opportunistic relay protocol for vehicular road-side access with fading channels, in IEEE International Conference on Network Protocols (ICNP), 2010, pp. 233-242.
[10]J. Ott and D. Kutscher, Drive-thru Internet: IEEE 802.11b for automobile users, in IEEE INFOCOM 2004, 2004, p. 373.
[11]V. Bychkovsky, B. Hull, A. Miu, H. Balakrishnan, and S. Madden, A measurement study of vehicular internet access using in situ Wi-Fi networks, presented at the Proceedings of the 12th annual international conference on Mobile computing and networking, Los Angeles, CA, USA, 2006.
[12]D. Hadaller, S. Keshav, T. Brecht, and S. Agarwal, Vehicular opportunistic communication under the microscope, presented at the Proceedings of the 5th international conference on Mobile systems, applications and services, San Juan, Puerto Rico, 2007.
[13]K. Younghyun, K. Jaeduck, K. Wonjung, and P. Sangheon, A Measurement Study on Internet Access in Vehicular Wi-Fi Networks, in IEEE Vehicular Technology Conference Fall (VTC'10), 2010, pp. 1-5.
[14]T. Wee Lum, L. Wing Cheong, Y. OnChing, and H. Tan Hing, Analytical Models and Performance Evaluation of Drive-thru Internet Systems, IEEE Journal on Selected Areas in Communications, vol. 29, pp. 207-222, 2011.
[15]A. Balasubramanian, R. Mahajan, A. Venkataramani, B. N. Levine, and J. Zahorjan, Interactive wifi connectivity for moving vehicles, ACM SIGCOMM Computer Communication Review, vol. 38, pp. 427-438, 2008.
[16]J. Eriksson, H. Balakrishnan, and S. Madden, Cabernet: vehicular content delivery using WiFi, presented at the Proceedings of the 14th ACM international conference on Mobile computing and networking, San Francisco, California, USA, 2008.
[17]X. Chen, P. Gangwal, and D. Qiao, Practical Rate Adaptation in Mobile environments, presented at the Proceedings of the 2009 IEEE International Conference on Pervasive Computing and Communications, 2009.
[18]P. Shankar, T. Nadeem, J. Rosca, and L. Iftode, CARS: Context-Aware Rate Selection for vehicular networks, in IEEE International Conference on Network Protocols (ICNP'08), 2008, pp. 1-12.
[19]J. Camp and E. Knightly, Modulation rate adaptation in urban and vehicular environments: cross-layer implementation and experimental evaluation, presented at the Proceedings of the 14th ACM international conference on Mobile computing and networking, San Francisco, California, USA, 2008.
[20]J. Ott and D. Kutscher, A disconnection-tolerant transport for drive-thru Internet environments, in IEEE INFOCOM 2005, 2005, pp. 1849-1862 vol. 3.
[21]P. Deshpande, A. Kashyap, C. Sung, and S. R. Das, Predictive methods for improved vehicular WiFi access, presented at the Proceedings of the 7th international conference on Mobile systems, applications, and services, Poland, 2009.
[22]Z. Hao and C. Guohong, rDCF: A Relay-Enabled Medium Access Control Protocol for Wireless Ad Hoc Networks, IEEE Transactions on Mobile Computing, vol. 5, pp. 1201-1214, 2006.
[23]Z. Haitao, W. Jibo, and X. Yong, A rate-adaptive cooperative MAC protocol based on RTS/CTS scheme for MANETs, in 2007. AccessNets '07. Second International Conference on Access Networks ＆ Workshops, 2007, pp. 1-6.
[24]M. S. Gokturk and O. Gurbuz, Cooperative MAC protocol with distributed relay actuation, presented at the Proceedings of the 2009 IEEE conference on Wireless Communications ＆ Networking Conference, Budapest, Hungary, 2009.
[25]M. Khalid, W. Yufeng, R. In-ho, and R. Sankar, Two-Relay-Based Cooperative MAC Protocol for Wireless Ad hoc Networks, IEEE Transactions on Vehicular Technology, vol. 60, pp. 3361-3373, 2011.
[26]D. J. Love, R. W. Heath, V. K. N. Lau, D. Gesbert, B. D. Rao, and M. Andrews, An overview of limited feedback in wireless communication systems, IEEE Journal on Selected Areas in Communications, vol. 26, pp. 1341-1365, 2008.
[27]K. Il Han, P. Seung Young, D. J. Love, and K. Sung Jin, Partial Channel State Information Unitary Precoding and Codebook Design for MIMO Broadcast Systems, in IEEE Global Telecommunications Conference (GLOBECOM '07) 2007, pp. 1607-1611.
[28]N. Ahmed, M. A. Khojastepour, A. Sabharwal, and B. Aazhang, Outage minimization with limited feedback for the fading relay channel, IEEE Transactions on Communications, vol. 54, pp. 659-669, 2006.
[29]T. T. Pham, H. H. Nguyen, and H. D. Tuan, Power Allocation in Orthogonal Wireless Relay Networks With Partial Channel State Information, IEEE Transactions on Signal Processing, vol. 58, pp. 869-878, 2010.
[30]A. S. Ibrahim, A. K. Sadek, S. Weifeng, and K. J. R. Liu, Cooperative communications with partial channel state information: When to cooperate?, in IEEE Global Telecommunications Conference (GLOBECOM'05), 2005, pp. 5 pp.-3072.
[31]O. Munoz-Medina, J. Vidal, and A. Agustin, Linear Transceiver Design in Nonregenerative Relays With Channel State Information, IEEE Transactions on Signal Processing, vol. 55, pp. 2593-2604, 2007.
[32]S. Kim, H. Roh, and W. Lee, CMAC-ORS: a cooperative MAC protocol with on-demand relay selection for wireless LANs, ACM SIGMOBILE Mobile Computing and Communications Review, vol. 14, pp. 25-27, 2010.
[33]N. Marchenko, E. Yanmaz, H. Adam, and C. Bettstetter, Selecting a Spatially Efficient Cooperative Relay, in IEEE Global Telecommunications Conference (GLOBECOM'09) 2009, pp. 1-7.
[34]M. Zorzi and R. R. Rao, Geographic random forwarding (GeRaF) for ad hoc and sensor networks: multihop performance, IEEE Transactions on Mobile Computing, vol. 2, pp. 337-348, 2003.
[35]Z. Bin and M. C. Valenti, Practical relay networks: a generalization of hybrid-ARQ, IEEE Journal on Selected Areas in Communications, vol. 23, pp. 7-18, 2005.
[36]M.-H. Lu, P. Steenkiste, and T. Chen, Design, implementation and evaluation of an efficient opportunistic retransmission protocol, presented at the Proceedings of the 15th annual international conference on Mobile computing and networking, Beijing, China, 2009.
[37]A. F. Molisch, Wireless Communications, 2005.
[38]D. Tse and P. Viswanath, Fundamentals of Wireless Communication, 2005.
[39]M.Nakagami, The-m-distribution—A general formula of intensity distribution of rapid fading, in StatisticalMethods in RadioWave Propagation, W. G. Hoffman, Ed., ed, 1960, pp. 3–36.