A scheduling algorithm considering packet loss rate & remaining time in WiMAX network
| Autor: | Wei-Ting Shao, 邵偉庭 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 IEEE 802.16 Standard is a Wireless Metropolitan Area Network (WMAN). To ensure the Quality of Service (QoS) of different application, the service flows are classified into five classes. In IEEE 802.16, the scheduling algorithms for allocating bandwidth is not defined. Therefore, to design an excellent scheduling algorithm satisfying the QoS requirements of all classes become a main research topic. If the waiting time is over the maximum latency of a real-time packet, it will be discarded. In “A ratio limited scheduling algorithm for WiMAX network according to packet remaining time[1]”,this packet will be scheduled as long as the remaining packet time is less than 0.6 times of the average packet remaining time for ertPS. The threshold for the remaining time set is 0.4 times for rtPS.In “Adaptive Ratio Limited Scheduling Algorithm for WiMAX Network according to Packet Left Time[2]”,set the remaining time threshold to x and y for ertPS and rtPS. The starting values (0.4, 0.3) and (0.6, 0.4). To ensure that the packet loss rate of real-time polling service is limited within the required range,the packet loss rate of real-time polling service becomes larger, x will be smaller and y will be larger. However,the starting value (x,y) is (0.6, 0.4), the packet loss rate in ARL is not better than RL since the ertPS is allocated too large bandwidth when the starting value x 0.6 for the ARL algorithm.As the traffic load is increased (the packet loss rate become larger),the bandwidth’s allocation does not decrease significantly even if the value of x becomes smaller for ertPS.The remaining available bandwidth can not be increased for rtPS, so the packet loss rate of rtPS can not be improved. In this paper, we modify the ARL algorithm. When rtPS packet loss rate reaches the required threshold value, in addition to reducing the value of x, it also limits the maximum bandwidth that can be allocated so that rtPS can be allocated the maximum in this frame. The ARL algorithm is improved by 1% more bandwidth than the one to the previous frame. Simulation results show that (x,y) is (0.6, 0.4), the algorithm proposed in this paper can improve the packet loss rate of rtPS. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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