Efficient channel allocation tree generation for data broadcasting in a mobile computing environment

Abstract

The research issue of broadcasting has attracted a considerable amount of attention in a mobile computing system. By utilizing broadcast channels, a server continuously and repeatedly broadcasts data to mobile users. These broadcast channels are also known as "broadcast disks" from which mobile users can retrieve data. Using broadcasting, mobile users can obtain the data of interest efficiently and only need to wait for the required data to present on the broadcast channel. The issue of designing proper data allocation in the broadcast disks is to reduce the average expected delay of all data items. We explore in this paper the problem of generating hierarchical broadcast programs with the data access frequencies and the number of broadcast disks in a broadcast disk array given. Specifically, we first transform the problem of generating hierarchical broadcast programs into the one of constructing a channel allocation tree with variant-fanout. By exploiting the feature of tree generation with variant-fanout, we develop a heuristic algorithm VF^K to minimize the expected delay of data items in the broadcast program. In order to evaluate the solution quality obtained by algorithm VF^K and compare its resulting broadcast program with the optimal one, we devise an algorithm OPT based on a guided search to obtain the optimal solution. Performance of these algorithms is comparatively analyzed. Sensitivity analysis on several parameters, including the number of data items and the number of broadcast disks, is conducted. It is shown by our simulation results that by exploiting the feature of variant-fanout in constructing the channel allocation tree, the solution obtained by algorithm VF^K. is of very high quality and is in fact very close to the optimal one resulted by algorithm OPT. Moreover, algorithm VF^K is of very good scalability which is important for algorithm VF^K to be of practical use to generate hierarchical broadcast programs dynamically in a mobile computing environment.

References

1. {1} S. Acharya, R. Alonso, M. Franklin and S. Zdonik, Broadcast disks: data management for asymmetric communication environments, in: Proceedings of ACM SIGMOD (March 1995) pp. 199-210.
2. {2} S. Acharya, M. Franklin and S. Zdonik, Balancing push and pull for data broadcast, in: Proceedings of ACMSIGMOD (May 1997) pp. 183-194.
3. {3} S. Acharya and S. Muthukrishnan, Scheduling on-demand broadcasts: new metrics and algorithms, in: Proceedings of the 4th ACM/IEEE International Conference on Mobile Computing and Networking (October 1998) pp. 43-54.
4. {4} A. Bar-Noy, J. Naor and B. Schieber, Pushing dependent data in Clients-Providers-Servers systems, in: Proceedings of the 6th ACM International Conference on Mobile Computing and Networking (August 2000) pp. 222-230.
5. {5} D. Barbara, Mobile computing and databases -- a survey, IEEE Transactions on Knowledge and Data Engineering 11(1) (1999) 108-117.
6. {6} M.-S. Chen, P.S. Yu and K.-L. Wu, Indexed sequential data broadcasting in wireless mobile computing, in: 17th IEEE International Conference on Distributed Computing Systems (1997) pp. 124-131.
7. {7} T.H. Gormen, C.E. Leiserson and R.L. Rivest, Introduction to Algorithms (MIT Press, Cambridge, MA, 1990).
8. {8} A. Datta, D.E. Vandermeer, A. Celik and V. Kumar, Broadcast protocols to support efficient retrieval from databases by mobile users, ACM Transactions on Database Systems, 24(1) (1999) 1-79.
9. {9} M.H. Dunham, Mobile computing and databases, in: International Conference on Data Engineering (February 1998), tutorial.
10. {10} J. Gray, P. Sundaresan, S. Englert, K. Baclawski and P.J. Weinberger, Quickly generating billion-record synthetic databases, in: Proceedings of ACM SIGMOD (March 1994) pp. 243-252.
11. {11} Q. Hu, D.L. Lee and W.-C. Lee, Performance evaluation of a wireless hierarchical data dissemination system, in: Proceedings of the the Fifth Annual International Conference on Mobile Computing and Networking (1999) pp. 163-173.
12. {12} Q. Hu, W.-C. Lee and D.L. Lee, A hybrid indexing technique for power conserving wireless data broadcast, Journal on Distributed and Parallel Databases 9(2) (2001) 151-177.
13. {13} Q. Hu, W.-C. Lee and D.L. Lee, Indexing techniques for wireless data broadcast under data clustering and scheduling, in: Proceedings of the Eighth International Conference on Information and Knowledge Management (November 1999) pp. 351-358.
14. {14} T. Imielinski, S. Viswanathan and B. Badrinath, Data on air: organization and access, IEEE Transactions on Knowledge and Data Engineering 9(3) (1997) 353-372.
15. {15} J. Jing, A. Helal and A. Elmagarmid, Client-server computing in mobile environments, ACM Computing Surveys 31(2) (1999) 117-157.
16. {16} R.C.T. Lee, R.C. Chang, S.S. Tseng and Y.T. Tsai, Introduction to the Design and Analysis of Algorithms (Unalis Press).
17. {17} W.-C. Lee and D.-L. Lee, Signature caching techniques for information filtering in mobile enviroments, Wireless Networks 5(1) (1999) 57-67.
18. {18} S.-C. Lo and A.L.P. Chen, Optimal index and data allocation in multiple broadcast channels, in: Proceedings of the 16th International Conference on Data Engineering (March 2000) pp. 293-302.
19. {19} N.J. Nilsson, Principles of Artificial Intelligence (Springer, Berlin, 1982).
20. {20} E. Pitoura and P.K. Chrysanthis, Exploiting versions for handling updates in broadcast disks, in: Proceedings of 25th International Conference on Very Large Data Bases (September 1999) pp. 114-125.
21. {21} N. Shivakumar and S. Venkatasubramanian, Energy efficient indexing for information dissemination in wireless systems, Wireless Networks and Applications 1(4) (1996) 433-446.
22. {22} K. Stathatos, N. Roussopoulos and J.S. Baras, Adaptive data broadcast in hybrid networks, in: Proceedings of the 23rd International Conference on Vary Large Data Bases (August 1997) pp. 326-335.
23. {23} C.-J. Su and L. Tassiulas, Broadcast scheduling for information distribution, in: Proceedings of the 6th IEEE International Conference on Information and Communication (April 1997) pp. 109-117.
24. {24} C.-J. Su and L. Tassiulas, Joint broadcast scheduling and user's cache management for efficient information delivery, in: Proceedings of the 4th ACM/IEEE International Conference on Mobile Computing and Networking (October 1998) pp. 33-42.
25. {25} N.H. Vaidya and S. Hameed, Scheduling data broadcast in: asymmetric communication environments, Wireless Networks 5(3) (1999) 171-182.
26. {26} WAP application in Nokia, http://www.nokia.com/ corporate/wap/future.html.
27. {27} WAP application in Unwired Planet, Inc., http://phone.com.
28. {28} M.-H. Yang, L.-W. Chen, Y.-C. Tseng and J.-P. Sheu, A traveling salesman mobility model and its location tracking in PCS networks, in: Proceedings of the 21st IEEE International Conference on Distributed Computing Systems (April 2001) pp. 517-524.

Index Terms

• Computer systems organization

  • Architectures

    • Other architectures

      • Special purpose systems

• Networks

  • Network protocols

  • Network services

    • Network management

  • Network types

    • Mobile networks

    • Wireless access networks