An Efficient Routing Tree Algorithm for Combined Uplink and Downlink Subframes on Centralized Scheduling in IEEE 802.16 Based Wireless Mesh Networks

Ali Behfarnia, Vahid Tabataba Vakili
DOI: 10.4236/ijcns.2011.44026                

Abstract

IEEE 802.16 mesh mode defines routing tree for transmitting data in centralized scheduling but it does not define any explicit proposal for combining uplink and downlink subframes. Deploying combined uplink and downlink subframes on the centralized scheduling scheme can be more flexible and utilization is improved. However, existing interferences among the transmission of neighboring nodes lead to performance reduction of the network. In this paper, an efficient routing tree algorithm is proposed with combined uplink and downlink slot allocation on the centralized scheduling scheme which can abate interferences in the network. This algorithm allows more subscriber stations to transmit concurrently and so improves spatial reuse in the network. Also, the algorithm uses multi-channel and single channel systems and considers relay model, smoothing switching frequently between transmitting and receiving in successive time slots and fairness in the network. Extensive simulation results demonstrate the effectiveness of the proposed method in terms of scheduling length, link concurrency ratio, network throughput and Channel Utilization Ratio (CUR).

Keywords

IEEE 802.16, Wireless Mesh Network, Centralized Scheduling, Slot Allocation, Routing Tree

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	I. F. Akyildiz, X. Wang and W. Wang, “Wireless Mesh Networks: A Survey,” Elsevier Journal of Computer Networks, Vol. 47, No. 4, March 2005, pp. 445-487.
[2]	IEEE Standard 802.16-2004, “Local and Metropolitan Area Networks—Part 16: Air Interface for Fixed Broadband Wireless Access Systems,” October 2004.
[3]	B. Han, F. P. Tso, L. Lin and W. Jia, “Performance Evaluation of Scheduling in IEEE 802.16 Based Wireless Mesh Networks,” Proceedings of International Conference on Mobile Adhoc and Sensor Systems, Vancouver, 9-12 October 2006, pp. 789-794. doi:10.1109/MOBHOC.2006.278652
[4]	B. Han, W. J. Jia and L. D. Lin, “Performance Evaluation of Scheduling in IEEE 802.16 Based Wireless Mesh Networks,” Elsevier Journal of Computer Communications, Vol. 30, No. 4, February 2007, pp. 782-792.
[5]	S. Liu, S. Feng, W. Ye and H. Zhuang, “Slot Allocation Algorithms in Centralized Scheduling Scheme for IEEE 802.16 Based Wireless Mesh Networks,” Elsevier Journal of Computer Communications, Vol. 32, No. 5, March 2009, pp. 943-953.
[6]	Y. Tang, Y. Yao and J. Yu, “A Novel Joint Centralized Scheduling and Channel Assignment Scheme for IEEE 802.16 Mesh Networks,” Proceedings of 4th International Conference on Computer Science & Education, Nanning, 25-28 July 2009, pp. 289-293.
[7]	P. Du, W. Jia, L. Huang and W. Lu, “Centralized Scheduling and Channel Assignment in Multi-Channel Single-Transceiver WiMax Mesh Network,” Proceedings of IEEE Wireless Com- munications and Networking Conference, Hong Kong, 11-15 March 2007, pp. 1734-1739.
[8]	P. R. Sheu, C. F. Hu, C. C. Liou, F. C. Chuang and Y. C. Chen, “An Efficient and Interference-Aware Centralized Routing Tree Algorithm for the Routing and Packet Scheduling Problem in IEEE 802.16 Mesh Networks,” Proceedings of International Conference on Communication and Mobile Computing, Shenzhen, 12-14 April 2010, pp. 496-503. doi:10.1109/CMC.2010.340
[9]	A. Al-Hemyari, C. K. Ng, N. K. Noordin, A. Ismail and S. Khatun, “Cross Layer Design in 802.16d,” Australian Journal of Basic and Applied Sciences, Vol. 3, No. 3, 2009, pp. 1591-1600.
[10]	A. Al-Hemyari, C. K. Ng, N. K. Noordin, A. Ismail and S. Khatun, “Constructing Routing Tree for Centralized Scheduling Using Multi-Channel Single Transceiver System in 802.16 Mesh Mode,” Proceedings of IEEE Internatinal Conference on RF and Microwave, Kuala Lumpur, 2-4 December 2008, pp. 192-196.