摘要
在這篇論文中，我們研究超寬頻 (Ultra-Wideband, UWB)隨意網路的效能，其中多個站台可以彼此直接進行通訊。因為接收端需要跟每一筆傳送的資料達成同步，超寬頻網路的同步overhead非常嚴重。為了有效減少時間同步所需的overhead，一個正在傳送的站台可以在MAC層將來自上層的多個封包組成一個叢集訊框。首先，我們考慮均質流量情形。在這邊我們不是假設每一個站台都處於飽和狀態，也就是每一個站台總是有訊框要傳送，我們考慮較真實的情形，也就是Poisson封包抵達流量模型。此外，每一個站台都有一個有限的佇列。我們使用離散時間馬可夫鏈來塑模所研究的系統。尤其，每一個站台都被塑模成為一個M/G[Bmin,Bmax]/1/K佇列系統。我們推導一個解析方法來計算感興趣的效能量度，例如，成功送達率，平均端對端延遲，平均佇列延遲，平均服務時間以及溢位機率。因為在無線通道裡會遭受到比有線通道更高的位元錯誤率，所以我們也考慮了有著非零錯誤率的情形。此外，我們也考慮異質流量情形，其中有兩種使用者且為了要提供服務差異性，兩種使用者使用不同的封包結合機制。提供負載、位元錯誤率以及封包結合機制對於我們感興趣的每一種使用者的系統效能量度的影響是透過我們所提出的數學模型之解析結果來顯示。

In this thesis, we study the performance of Ultra-Wideband (UWB) ad hoc networks, where multiple stations can communicate directly with each other. Since the receiver must synchronize with every transmitted data, synchronization overhead is significant in UWB networks. To reduce the synchronization overhead effectively, a transmitting station is allowed to assemble or assemble multiple packets from the upper-layer into a burst frame at MAC layer. First, we study homogeneous traffic cases. Instead of assuming that there is always a frame at each station ready to send, we consider the more realistic Poisson arrival traffic model. Furthermore, each station has a finite queue. A discrete-time Markov chain is used to characterize the system studied. In particular, each station is modeled as an M/G[Bmin,Bmax]/1/K queueing system. An analytical method is derived to calculate the performance measures of interest, e.g., throughput, average end-to-end delay, average queueing delay, average service time, and overflow probability. Since the wireless channel suffers from much higher bit error rate (BER) than its wired counterpart, so we also consider the scenarios with non-zero bit error rate. Furthermore, we also study heterogeneous traffic cases, where there are two classes of users using different packet assembly policies in order to support service differentiation. The effects of offered load, BER and packet assembly policy on the performance measures of interest for each class of users are demonstrated with our analytical results.

[1] First report and order in the matter of revision of part 15 of the commissions rules regarding ultra-wideband transmission systems, Federal Communications Commission (FCC 02-48), std., ET Docket 98-153, Apr. 2002.
[2] IEEE P802.15-04/0137rl, “DS-UWB physical layer submission to 802.15 Task Group 3a,” Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs), Mar. 2004.
[3] S. Roy, J. R. Foerster, V. S. Somayazulu, and D. G. Leeper, “Ultra-wideband Radio Design: The Promise of High-Speed, Short Range Wireless Connectivity, ”Proceedings of the IEEE, Vol. 92, Issue 2, pp. 259-311, Feb. 2004.
[4] S. S. Kolenchery, J. K. Townsend, and J. A. Freebersyser, “A Novel Impulse Radio Network for Tactical Military Wireless Communications,” IEEE MILCOM’98, Vol. 1, pp. 59 – 65, Oct. 1999.
[5] J. Ding, L. Zhao, S. Medidi, and K. Sivalingam, “MAC Protocol for Ultra-Wide-Band (UWB) Wireless Networks: Impact of Channel Acquisition Time”, SPIE ITCOM, pp. 97-106, July 2002.
[6] K. Lu, D. Wu, and Y. Fang, “A Novel Framework for Medium Access Control in Ultra-Wideband Ad Hoc Networks,” Dynamics of Continuous, Discrete and Impulsive Systems (Series B): Applications and Algorithms 12(3), Special Issue on Ultra-Wideband Wireless Communications for Short Range Communications, Vol. 12, No.3, pp. 427-441, Jun. 2005.
[7] G. Bianchi, “Performance Analysis of the IEEE 802.11 Distributed Coordination Function,” IEEE JSAC, Vol. 18, No. 3, pp. 535-547, Mar. 2000.
[8] H. Wu, Y. Peng, K. Long, S. Cheng, and J. Ma, “Performance of Reliable Transport Protocol over IEEE 802.11 Wireless LAN: Analysis and Enhancement,” IEEE INFOCOM’02, Vol. 2, pp. 599-607, June 2002.
[9] H. Zhai, Y, Kwon, and Y. Fang, “Performance Analysis of IEEE 802.11 MAC Protocol in Wireless LANs,” Wiley Journal of Wireless Communications and Mobile Computing (WCMC), Vol. 4, pp. 917-931, Dec. 2004.
[10] K. Lu, D. Wu, Y. Fang, and R. C. Qiu, “Performance Analysis of A Burst-Frame-Based MAC Protocol for Ultra-Wideband Ad Hoc Networks,” IEEE ICC’05, Vol. 5, pp. 2937-2941, May 2005.
[11] K. Lu, J. Wang, D. Wu, and Y. Fang, “Performance of A Burst-Frame-based CSMA/CA Protocol for High Data Rate Ultra-Wideband Networks: Analysis and Enhancement,” ACM QShine’06, Aug. 2006.
[12] Z. Hadzi-Velkov and B. Spasenovski, “Saturation Throughput – Delay Analysis of IEEE 802.11 DCF in Fading Channel,” IEEE ICC’03, Vol. 3, pp. 121-126, May 2003.
[13] K. Lu, D. Wu, Y. Fang, and R. C. Qiu, “On Medium Access Control for High Data Rate Ultra-Wideband Ad Hoc Networks,” IEEE WCNC, Vol. 2, pp. 795-800, Mar. 2005.
[14] Y. Xiao, “Backoff-based Priority Schemes for IEEE 802.11,” IEEE ICC ’03, Vol. 3, pp. 1568-1572, May 2003.
[15] A. S. Tanenbaum, Computer Networks, 4th ed. Prentice-Hall, 2003.
[16] IEEE 802.11 WG, Part 11: Wireless LAN: Medium Access Control (MAC) and Physical Layer (PHY) Specification, Aug. 1999.
[17] G. Hebuterne and C. Rosenberg, “Arrival and Departure State Distributions in the General Bulk-Service Queue,” Naval Research Logistics, vol. 46, pp. 107-118, Feb. 1999.
[18] D. Gross and C. M. Harris, Fundamentals of Queueing Theorem, 3rd Edition, John Wiley.
[19] Wireless medium access control (MAC) and physical layer (PHY) specifications for high rate wireless personal area networks (WPANs), 2003.
[20] Y. Xiao, “Performance Analysis of Priority Schemes for IEEE 802.11 and IEEE 802.11e Wireless LANs” IEEE Transactions on Wireless Communications, Vol. 4, Issue 4, pp. 1506-1515, July 2005.
[21] A. Khalaj, N. Yazdani, and M. Rahgozr, “Service Differentiation and Fairness in IEEE 802.11 DCF”, IEEE ICC’05, Vol. 1, pp. 526-530, Nov. 2005.
[22] T. M. Lim, B. S. L. Francis, C. K. Yeo, and M. Amir, “Ad hoc Qs: MAC-independent Traffic Differentiation in IEEE 802.11-based Ad Hoc WLAN” IEEE ICC’05, Vol. 1, pp. 510-514, Nov. 2005.