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Issue No.03 - March (2012 vol.11)
pp: 478-491
P. Djukic , Meshlntelligence, Inc., Ottawa, ON, Canada
P. Mohapatra , Dept. of Comput. Sci., Univ. of California at Davis, Davis, CA, USA
We implement a new software-based multihop TDMA MAC protocol (Soft-TDMAC) with microsecond synchronization using a novel system interface for development of 802.11 overlay TDMA MAC protocols (SySI-MAC). SySI-MAC provides a kernel independent message-based interface for scheduling transmissions and sending and receiving 802.11 packets. The key feature of SySI-MAC is that it provides near deterministic timers and transmission times, which allows for implementation of highly synchronized TDMA MAC protocols. Building on SySI-MAC's predictable transmission times, we implement Soft-TDMAC, a software-based 802.11 overlay multihop TDMA MAC protocol. Soft-TDMAC has a synchronization mechanism, which synchronizes all pairs of network clocks to within microseconds of each other. Building on pairwise synchronization, Soft-TDMAC achieves tight network-wide synchronization. With network-wide synchronization independent of data transmissions, Soft-TDMAC can schedule arbitrary TDMA transmission patterns. For example, Soft-TDMAC allows schedules that decrease end-to-end delay and take end-to-end rate demands into account. We summarize hundreds of hours of testing Soft-TDMAC on a multihop testbed, showing the synchronization capabilities of the protocol and the benefits of flexible scheduling.
wireless LAN, access protocols, synchronisation, time division multiple access, end-to-end rate demands, soft-TDMAC, software-based 802.11, overlay TDMA MAC, microsecond synchronization, software-based multihop TDMA MAC protocol, 802.11 packets, TDMA transmission patterns, end-to-end delay, Synchronization, Time division multiple access, Spread spectrum communciation, IEEE 802.11 Standards, Media Access Protocol, Schedules, Media Access Protocols, network synchronization., Multihop TDMA MAC, 802.11 overlay MAC
P. Djukic, P. Mohapatra, "Soft-TDMAC: A Software-Based 802.11 Overlay TDMA MAC with Microsecond Synchronization", IEEE Transactions on Mobile Computing, vol.11, no. 3, pp. 478-491, March 2012, doi:10.1109/TMC.2011.56
[1] P. Djukic and P. Mohapatra, “Soft-TDMAC: Software TDMA-Based MAC over Commodity 802.11 Hardware,” Proc. IEEE INFOCOM, pp. 1836-1844, Apr. 2009.
[2] S. Xu and T. Saadawi, “Does the IEEE 802.11 MAC Protocol Work Well in Multihop Wireless Ad Hoc Networks,” IEEE Comm. Magazine, vol. 39, no. 6, pp. 130-137, June 2001.
[3] IEEE P802.11s/D1.01, Draft 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 Amendment: ESS Mesh Networking, IEEE, 2006.
[4] A. Khattab, J. Camp, C. Hunter, P. Murphy, A. Sabharwal, and E. Knightly, “WARP—A Flexible Platform for Clean-Slate Wireless Medium Access Protocol Design,” ACM SIGMOBILE Mobile Computing and Comm. Rev., vol. 12, no. 1, pp. 56-58, Jan. 2008.
[5] A. Rao and I. Stoica, “An Overlay MAC Layer for 802.11 Networks,” Proc. Third Int'l Conf. Mobile Systems, Applications, and Services (MobiSys '05), pp. 135-148, 2005.
[6] M. Neufeld, J. Fifield, C. Doerr, A. Sheth, and D. Grunwald, “SoftMAC-Flexible Wireless Research Platform,” Proc. Fourth Workshop Hot Topics in Networks (HotNets), 2005.
[7] C. Doerr, M. Neufeld, J. Fifield, T. Weingart, D.C. Sicker, and D. Grunwald, “MultiMAC—An Adaptive MAC Framework for Dynamic Radio Networking,” Proc. First IEEE Int'l Symp. New Frontiers in Dynamic Spectrum Access Networks (DySPAN '05), pp. 548-555, 2005.
[8] A. Sharma, M. Tiwari, and H. Zheng, “MadMAC: Building a Reconfigurable Radio Testbed Using Commodity 802.11 Hardware,” Proc. First IEEE Workshop Networking Technologies for Software Defined Radio Networks (SDR '06), pp. 78-83, 2006.
[9] A. Sharma and E.M. Belding, “FreeMAC: Framework for Multi-Channel MAC Development on 802.11 Hardware,” Proc. ACM Workshop Programmable Routers for Extensible Services of Tomorrow (PRESTO '08), pp. 69-74, 2008.
[10] B. Raman and K. Chebrolu, “Design and Evaluation of a New MAC Protocol for Long-Distance 802.11 Mesh Networks,” Proc. ACM MobiCom, pp. 156-169, 2005.
[11] R. Patra, S. Nedevschi, S. Surana, A. Sheth, L. Subramanian, and E. Brewer, “WiLDNet: Design and Implementation of High Performance Wifi Based Long Distance Networks,” Proc. Fourth USENIX Symp. Networked Systems Design and Implementation (NSDI '07), pp. 87-100, 2007.
[12] D. Koutsonikolas, T. Salonidis, H. Lundgren, P. LeGuyadec, Y.C. Hu, and I. Sheriff, “TDM MAC Protocol Design and Implementation for Wireless Mesh Networks,” Proc. ACM Int'l Conf. Emerging Networking EXperiments and Technologies (CoNEXT '08), pp. 1-12, 2008.
[13] G. Narlikar, G. Wilfong, and L. Zhang, “Designing Multihop Wireless Backhaul Networks with Delay Guarantees,” Proc. IEEE INFOCOM, pp. 1-12, 2006.
[14] D.L. Mills, Computer Network Time Synchronization: The Network Time Protocol. CRC, 2006.
[15] J. Elson and D. Estrin, “Time Synchronization for Wireless Sensor Networks,” Proc. 15th Int'l Parallel and Distributed Processing Symp. (IPDPS '01), p. 186, 2001.
[16] M.L. Sichitiu and C. Veerarittiphan, “Simple, Accurate Time Synchronization for Wireless Sensor Networks,” Proc. IEEE Wireless Comm. and Networking (WCNC '03), vol. 2, pp. 1266-1273, 2003.
[17] K. Römer, “Time Synchronization in Ad Hoc Networks,” Proc. ACM MobiHoc, pp. 173-181, 2001.
[18] S. Ganeriwal, R. Kumar, and M.B. Srivastava, “Timing-Sync Protocol for Sensor Networks,” Proc. First Int'l Conf. Embedded Networked Sensor Systems (SenSys '03), pp. 138-149, 2003.
[19] MadWifi, http:/, 2011.
[20] P. Djukic and S. Valaee, “Delay Aware Link Scheduling for Multi-Hop TDMA Wireless Networks,” IEEE/ACM Trans. Networking, vol. 17, no. 3, pp. 870-883, June 2009.
[21] “The Network Simulator - ns-2,”, 2011.
[22] C. Hedrick, “Routing Information Protocol,” IETF RFC 1058,, June 1988.
[23] D.W. Allan, “Time and Frequency (Time-Domain) Characterization, Estimation, and Prediction of Precision Clocks and Oscillators,” IEEE Trans. Ultrasonics, Ferroelectrics, Frequency Control, vol. 34, no. 6, pp. 647-654, Nov. 1987.
[24] R. Solis, V.S. Borkar, and P. Kumar, “A New Distributed Time Synchronization Protocol for Multihop Wireless Networks,” Proc. 45th IEEE Conf. Decision and Control, pp. 2734-2739, Dec. 2006.
[25] “Linux Kernel,” http:/, 2006.
[26] P. Djukic and S. Valaee, “Getting the Most of WiFi Mesh Networks with 802.16 Mesh Emulation,” Int'l J. Parallel, Emergent and Distributed Systems, vol. 23, no. 6, pp. 1744-5760, 2008.
[27] I. Molnar, “Real-Time Patches for Linux 2.6 Kernel,” rt, 2011.
[28] IEEE Std 1003.1, The Open Group Base Specifications Issue 6, IEEE, 2004.
[29] “GNU General Public License,”, 2011.
[30] SoftTDMAC, http:/, 2011.
[31] 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, 2007.
[32] L.A. Grieco and S. Mascolo, “Performance Evaluation and Comparison of Westwood+, New Reno, and Vegas TCP Congestion Control,” ACM SIGMOBILE Mobile Computer Comm. Rev., vol. 34, no. 2, pp. 25-37, Apr. 2004.
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