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Load Awareness Multi-Channel MAC Protocol Design for Ad Hoc Networks

Load Awareness Multi-Channel MAC Protocol Design for Ad Hoc Networks. Chih -Min Chao and Kuo -Hsiang Lu. Department of Computer Science and Engineering National Taiwan Ocean University. IEEE Sensor Networks, Ubiquitous and Trustworthy Computing (SUTC) 2008. Outline. Introduction

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Load Awareness Multi-Channel MAC Protocol Design for Ad Hoc Networks

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  1. Load Awareness Multi-Channel MAC Protocol Design for Ad Hoc Networks Chih-Min Chao and Kuo-Hsiang Lu Department of Computer Science and Engineering National Taiwan Ocean University • IEEE Sensor Networks, Ubiquitous and Trustworthy Computing (SUTC) 2008

  2. Outline • Introduction • Related Work • Proposed Load-awareness Multichannel MAC (LAMM) Protocol • Performance Evaluation • Conclusions

  3. Introduction • The MAC protocol of IEEE 802.11 standard is designed for accessing a single channel. • It is well known that utilizing multiple channels can increase spatial reuse and hence enhance network throughput. • Channel allocation problem

  4. Related work [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 ACM MobiCom, 2004.

  5. SSCH A B B B A A A B B A B B A A B B B A A A

  6. Related work [7] • J. So and N. Vaidya. • Multi-Channel MAC for Ad Hoc Networks: Handling Multi-Channel Hidden Terminals Using A Single Transceiver. • In Proceedings of ACM MobiHoc, 2004.

  7. Related work [7] -- MMAC ATIM window DATA window ATIM ATIM-RES A Beacon B ATIM-ACK Preferable Channel List (PCL)

  8. Related work [8] • C. Son, N.-H. Lee, B. Kim, and S. Bahk. • MAC Protocol using Asynchronous Multi-Channels in Ad Hoc Networks. • In Proceedings of IEEE WCNC, 2007.

  9. Related work [8] -- SLKB • Each beacon interval is divided into three subintervals • Three asynchronous channels

  10. Related work • All the above mentioned multi-channel protocols operate in an environment where the number of channels is fixed. • They may suffer from either longer delay or higher collision probability when network load changes.

  11. Proposed LAMM protocol • The main idea of LAMM is to • Use less number of channels • When lightly loaded • Use more channels • When heavily loaded.

  12. Proposed LAMM protocol • Single transceiver • No control channel • The structure is similar to IEEE 802.11 PSM. • In LAMM, the ATIM/ATIM-ACK include • The number of pending packets

  13. Proposed LAMM protocol • Define a node A to be inactive if one of the following conditions holds • Attempt to send ATIM  But fails to deliver • Send ATIM  Not receive ATIM-ACK • No ATIM to send & Not receive any ATIM

  14. Proposed LAMM protocol • Each node maintains a variable CUito estimate the usage of channeli • At the beginning of each beacon interval, CUiis set to zero. • CUmax：indicates the maximum number of packets that can be sent during a data window. • Data rate：2Mbps • Beacon interval：100ms • Data interval：80ms • Packet size：512Bytes

  15. Proposed LAMM protocol • If CUi >= CUthrd • The inactive node switch to next channel (i+1) mod n • If CUi< CUthrdfor successively k times • Nodes reside on this channel should switch back to the default channel at the next beacon interval.

  16. Proposed LAMM protocol

  17. Performance Evaluation

  18. Performance Evaluation

  19. Performance Evaluation

  20. Performance Evaluation

  21. Performance Evaluation

  22. Conclusions • The authors propose a multi-channel MAC protocol LAMM that dynamically adjust the number of channels being utilized according to traffic load. • Reduces the packet delay • when the network is lightly loaded. • Increases spatial reuse • when heavily loaded. • The simulation results verify that LAMM performs well.

  23. Thank you

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