在本篇論文中，針對在隨建即連網路 (Ad hoc Network) 環境中不的多重通道(Multichannel)協定加以分類與分析，並提出在隨建即連多重通道無線網路環境中，除了考量在單一通道中會發生的碰撞問題之外，同時也必須考量在多重通道下在通道之間的切換所產生的干擾與碰撞。在使用多重通道時，干擾範圍(Interference Range)所照成的碰撞會因通道之間的切換複合，使得碰撞的情況更加難以預測與解決，此種問題稱之為The large interference range collision problems (LIRC problem)。參考的相關文獻中，設計多重通道協定時都只針對通道的配置(Channel assignment)問題進行設計，卻未針對LIRC問題做進一步的分析與解決。
針對上述有提出的問題，本篇論文提出一透過實體層的多重感測的協定，來對多重通道的使用情況進行預測，進而避免碰撞的發生。透過多根天線在不同通道上進行感測，節點能夠針對不同通道上所感測到的交換封包(Control Packet)或資料封包(Data Packet)所造成的訊號加以分析，用為判斷通道使用情形的依據。當節點擁有多重通道的資訊後，便可以在傳輸時選用空閒之通道以避免正在進行傳輸的傳輸對發生碰撞。此外，本篇論文提出使用忙碌音(Busy Tone)的方式解決LIRC問題，將使用通道的情形以訊號的方式透過忙碌音來傳達，讓節點同樣能夠依據所感測到忙碌音的不同而能夠加以分析並避免網路上碰撞的產生，並將使用忙碌音的協定延伸到能夠使用在三個以上的多重通道中。

The thesis proposes two collision avoidance multichannel MAC protocols to solve the large interference range collision (LIRC) problems occurred in most of multi-channel protocols for ad hoc networks. Most of the researches focus on the channel assignment without considering the interference range when designing the multichannel MAC protocols in wireless ad hoc networks. However, the collided situations become difficult to resolve since all the stations are separated in different channels and switch from channel to channel. In the thesis, the interference range is considered. By using two radios and a control channel, stations can know which data channels are idle or not, even if the station is transmitting or receiving the data. Stations need not decode control packets correctly, but the stations still can avoid collision. As the simulation results, the protocols proposed in the paper can indeed avoid collisions caused by blindly switching channel and increase the network throughput accordingly.

Contents
Contents I
List of Figures III
List of Tables V
1 Introduction 1
2 Related Work 3
3 Preliminaries 7
3.1 The de¯nition of ranges in single channel . . . . . . . . . . . . . . . . 7
3.2 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 On Avoiding LIRC Problems in Multichannel 13
4.1 Dual Carrier Senses Multichannel (DCSM) MAC Protocol . . . . . . 13
4.2 Coded Busy Tone Multichannel (CBTM) MAC Protocol . . . . . . . 18
4.3 Enhancement of N channels . . . . . . . . . . . . . . . . . . . . . . . 20
5 Performance Evaluations 21
6 Conclusions 23
Bibliography 25
Appendices 29
A International Conference Versions 29

List of Figures
2.1 Control channel based multichannel protocol. . . . . . . . . . . . . . 4
2.2 Home channel based multichannel protocol. . . . . . . . . . . . . . . 5
2.3 Channel Hopping based multichannel protocol. . . . . . . . . . . . . . 5
2.4 Contention window based multichannel protocol. . . . . . . . . . . . . 6
3.1 The relationship between three kinds of range. . . . . . . . . . . . . . 8
3.2 RTRC, SCRC, RCRC, ARPC, and IEEE 802.11 DCF are compared for
DAB varied from 10 m to 250 m in terms of (a) the energy consumption,
(b) the throughput, and (c) the energy e±ciency, respectively. . . . . 9
3.3 The station I is a interference station. . . . . . . . . . . . . . . . . . . 10
3.4 The collision occurs when switching the channel 2. . . . . . . . . . . . 10
3.5 Use the sender's CSR to cover the IR. . . . . . . . . . . . . . . . . . . 11
3.6 Use the receiver's CSR to cover the IR. . . . . . . . . . . . . . . . . . 11
4.1 RTS frame. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2 CTS frame. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.3 Send CTS packet both on control and data channel. . . . . . . . . . . 14
4.4 Using the CSR to cover the IR. . . . . . . . . . . . . . . . . . . . . . 15
4.5 Detect the di®erent CSR when at di®erent place. . . . . . . . . . . . 16
4.6 An example for protocol scenario. . . . . . . . . . . . . . . . . . . . . 17
4.7 The time shaft for the example. . . . . . . . . . . . . . . . . . . . . . 17
4.8 Receiver will send tone signal when receiving data packet. . . . . . . 19
4.9 At most 5 transmission pairs can covered the IR . . . . . . . . . . . . 19
5.1 The chain topology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.2 The impact of distance X on network throughput. . . . . . . . . . . . 22
5.3 The impact of packet length on network throughput. . . . . . . . . . 22

List of Tables
4.1 Comparison among Control and Data channel . . . . . . . . . . . . . 18

Bibliography
[1] IEEE Std 802.11-1999: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) speci¯cations. Institute of Electrical and Electronics Engineers, Inc., 1999.
[2] P. Bahl, R. Chandra, and J. Dunagan, "SSCH: Slotted seeded channel hopping for capacity improvement in IEEE 802.11 ad-hoc wireless networks," in Proceedings of the ACM International Conference on Mobile Computing and Networking (MOBICOM), 2004.
[3] P. Kyasanur and N. H. Vaidya, "Routing and link-layer protocols for multichannel multi-interface ad hoc wireless networks," in SIGMOBILE Mobile Computing and Communications Review, vol. 10, January, pp. 31-43.
[4] J. A. Patel, H. Luo, and I. Gupta, "A cross-layer architecture to exploit multichannel diversity with a single transceiver," in Proceedings of the IEEE INFOCOM, the Annual Joint Conference of the IEEE Computer and Communications Societies, May 2007, pp. 2261-2265.
[5] D. Qiao, S. Choi, A. Jain, and K. G. Shin, "MiSer: An optimal low-energy transmission strategy for IEEE 802.11a/h," in Proceedings of the ACM International Conference on Mobile Computing and Networking (MOBICOM), 2003, pp. 161-175.
[6] J. Rao and S. Biswas, "Transmission power control for 802.11: A carrier-sense based NAV extension approach," in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM), vol. 6, 2005, pp. 3439-3444.
[7] J. Shi, T. Salonidis, and E. W. Knightly, "Starvation mitigation through multichannel coordination in CSMA multi-hop wireless networks," in Proceedings of the ACM International Symposium on Mobile Ad Hoc Networking and Computing (MOBIHOC), 2006, pp. 214-225.
[8] K.-P. Shih, Y.-D. Chen, and C.-C. Chang, "Adaptive range-based power control for collision avoidance in wireless ad hoc networks," in Proceedings of the IEEE International Conference on Communications (ICC), 2007.
[9] H.-S. W. So, J. Walrand, and J. Mo, "McMAC: A parallel rendezvous multichannel MAC protocol," in Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC), March 2007.
[10] J. So and N. Vaidya, "Multi-channel MAC for ad hoc networks: Handling multichannel hidden terminals using a single transceiver," in Proceedings of the ACM International Symposium on Mobile Ad Hoc Networking and Computing (MOBIHOC), May 2004.
[11] S.-L. Wu, C.-Y. Lin, Y.-C. Tseng, and J.-L. Sheu, "A new multi-channel MAC protocol with on-demand channel assignment for multi-hop mobile ad hoc networks," in International Symposium on Parallel Architectures, Algorithms and Networks (ISPAN), 2000.
[12] S.-L. Wu, Y.-C. Tseng, C.-Y. Lin, and J.-P. Sheu, "A multi-channel MAC protocol with power control for multi-hop mobile ad hoc networks," in Computer Journal, vol. 45, 2002, pp. 101-110.
[13] K. Xu, M. Ger1a, and S. Bae, "How e®ective is the IEEE 802.11 RTS/CTS handshake in ad hoc networks?" in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM), vol. 1, 2002, pp. 72-76.
[14] Y. Zhou and S. M. Nettles, "Balancing the hidden and exposed node problems with power control in CSMA/CA-based wireless networks," in Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC), 2005, pp. 683-688.