WLAN Transmission Performance Improvement by Using Directive Antennas

• Main Authors: Chen-Wei Huang, 黃振維
• Other Authors: Hsueh-Jyh Li
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/93154634210825795582

碩士 === 國立臺灣大學 === 電信工程學研究所 === 91 === In indoor wireless communication environment, high-speed data rate transmission is significantly restricted to multipath fading in wireless local area network. For these reasons, improvement of communication quality and data transmission rate is a valuable topic to be studied. In this thesis, influences of multipath and transmission performance for using varieties of omni-directional and directive antennas are investigated. In general, antennas with omni-directional radiation patterns such as dipole and slot antenna are used due to unpredictable direction of incoming direct wave. On the other hand, directive antennas will be useful when knowing the direction of transmitting source. The experiments of indoor WLAN channel in several typical scenarios are conducted in this thesis. From results of measurement and simulation, it can be observed that suppression of multipath waves is more effective and RMS delay spread decreases for employing directive antennas with narrower beamwidths in indoor LOS condition. When considering indoor NLOS environment where direct wave is obstructed by pillars or persons, transmission quality compared with using omni-directional antennas is also considerably improved if directive antennas are used.