Because the relatively long headers in voice packets may cause unnecessary waste in network bandwidth, in this Thesis, we propose a dynamic MUX/DEMUX mechanism to compress the overhead headers in the VoIP packets. The proposed mechanism can dynamically adjust the length of the compressed VoIP packets for multiple VBR voice connections in a mixed WLAN and WiMAX environment. QoS in terms of voice jitter can be guaranteed after the multiplexed voice packets are de-multiplexed.
To validate the proposed mechanism, we implement two VoIP MUX/DEMUX gateways on Linux platform and place them in a mixed WLAN and WiMAX (IEEE 802.16a) network at NSYSU campus. On the VoIP MUX/DEMUX gateways, we implement four functions; (i) the header formats of two different mini compressions, (ii) the mechanism of compressing voice packets, (iii) multiple waiting buffers, and (iv) the mechanism of dynamically adjusting waiting time of voice packets from different sources. According to the experimental results, the proposed VoIP MUX/DEMUX mechanism has shown that it can substantially save WiMAX bandwidth and consistently stabilize packet arrival interval (PAI) of voice packets under different levels of background traffic (constant or burst). Thus, the QoS of voice communications are guaranteed through our proposed mechanism.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0817109-174325 |
| Date | 17 August 2009 |
| Creators | Huang, Cheng-Ming |
| Contributors | Tsang-Ling Sheu, Zi-Tsan Chou, Chung-Nan Lee, Wei-Kuang Lai, Tsung-Chuan Huang |
| 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-0817109-174325 |
| Rights | restricted, Copyright information available at source archive |
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