Differential Admission Control for HCCA in IEEE 802.11e

• Main Authors: Yu-Chin Lin, 林郁欽
• Other Authors: Cheng-Yuan Tang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/70298300719259948828

碩士 === 華梵大學 === 資訊管理學系碩士班 === 95 === 　　The space that the technical development of the Wireless LAN breakthrough the traditional wired LAN is limited. And the user can be access information in moving. However, the transmission rate is not high because of the limitation of bandwidth in WLAN and transmission media is easy to be interfered causing data to loss. Find to some research papers, there are several problems that will cause the increase of data loss and transmission delay. But it is unable to tolerate transmission multimedia data (such as the image, sound) in too many data loss or higher transmission delay in the WLAN. So how to offer good transmission quality in the WLAN has become one of the topic issues. 　　IEEE 802.11e QoS MAC standard protocol that IEEE 802.11 Task Group E suggests is passed formally in July of 2005. In HCCA model of this protocol designs a program of admission control unit. The purpose is effective to control the number of stations and the bandwidth can obtain the greatest utility at the same time. The parameter value of Physical Rate in the program is uses the Minimum Physical Rate from the TSPEC. But in the environment of actual operation, the Physical Rate may be changed when the station moves or signal power changes. Therefore, its efficiency of the original admission control program is not good in WLAN. This study will designs new admission control method－DAC(Differential Admission Control). In order to allow more Stations to transmit data at the same time, and enhance the QoS of WLAN.