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An Uplink Packet Scheduling Algorithm in Fixed PMP WiMAX Networks with TDD Frame Structure

Nazari, Sonia | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 40285 (52)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Beigy, Hamid
  7. Abstract:
  8. Worldwide interoperability for Microwave Access (WiMAX) is one of the most dominant cell-based broadband wireless metropolitan access technologies. Packet scheduling algorithm specifies the packet transmission order. In WiMAX standard, packet scheduling algorithm is not defined and its efficient design is left for developers and researchers. The existing researches in the scope of uplink packet scheduling, which is the most challenging packet scheduling scheme, consider only one cell. However the uplink available resources might not be enough when there are many packets that should be scheduled. To solve this problem, we propose an algorithm that uses the load balancing mechanisms that are usually handled by handover procedures to transfer the traffic of the user terminals from over-loaded cells to under-loaded cells. The proposed algorithm extends the scope from a single cell to multiple cells. In this algorithm, we use the base station (BS) initiated distributed load balancing mechanism in which handover is performed when the resource utilization passes a threshold. The problem of the already existing mechanisms is that no criteria are considered in threshold calculation. In our study, the threshold is calculated based on traffic characteristics of the connections. The other problem of the existing load balancing mechanisms is that no procedure is specified for selecting one or some user terminals in the overlapping area. In our algorithm, we check if the serving BS uplink resources can satisfy the required resource; if not, we conclude that handover is needed and based on scheduling parameters, we decide to map the traffic of which user terminal on to which target BS. The simulation results show that the proposed algorithm increases the overall throughput of the network and reduces the overall queue size.
  9. Keywords:
  10. Scheduling Algorithm ; Load Distribution ; Institute Electrical and Electronic Engineers (IEEE)802.16 Standard ; Wordwide Interoperability for Microwave Access (WIMAX)Networks

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