In a WiMAX network, four traffic types with different priorities are defined.
They are Unsolicited Grant Service (UGS), real-time Polling Service (rtPS),
non-real-time Polling Service (nrtPS), and Best Effort (BE). In this thesis, we propose
a Dynamic Bandwidth Allocation (DBA) scheme for BS to schedule the four
above-mentioned traffic types. By adopting Deficit Round Robin (DRR) scheduling,
DBA first assigns minimum quantum to each traffic type for transmission. When rtPS
packets exceed their delay constraints, without sacrificing the minimum requirements
of nrtPS and BE traffic, DBA borrows some quantum from nrtPS and BE to satisfy
the delay requirements of rtPS traffic. When nrtPS packets can not reach the
minimum transmission rate, without starving the BE traffic, DBA borrows some
quantum from BE to support the required throughput of nrtPS traffic. According to
the history record of borrowed quantum, DBA dynamically adjusts the assigned
quantum for the three traffic types. For the purpose of evaluation, we use NS-2 to
simulate the proposed DBA. We adjust the traffic load to analyze the performance in
terms of average packet delay, average throughput, and average packet loss ratio. The
simulation results show that the DBA, in comparison to a previous work, can promise
the delay constraints of rtPS, maintain the average throughput of nrtPS, and avoid the
starvation of BE, when the traffic load is high.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0904108-150356 |
| Date | 04 September 2008 |
| Creators | Chen, Chun-Chu |
| Contributors | Rung-Hung Gau, Tsung-Chuan Huang, Sheau-Ru Tong, Tsang-Ling Sheu, Wen-Shyang Hwang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0904108-150356 |
| Rights | withheld, Copyright information available at source archive |
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