Development and Evaluation of a Smart Antenna Test Bed for Wireless LAN

Yoshiharu DOI  Seigo NAKAO  Yasuhiro TANAKA  Takeo OHGANE  Yasutaka OGAWA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.9   pp.1449-1454
Publication Date: 2004/09/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Wave Technologies for Wireless and Optical Communications)
Category: Antennas and Propagation for Wireless Communications
Keyword: 
smart antenna,  wireless LAN,  software defined radio,  field test,  

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Summary: 
Research in smart antenna technology has progressed over the past few years and is gradually reaching the phase of practical use. We have developed a smart antenna test bed for wireless local area network (LAN) that is based on the IEEE802.11b. The objective is to improve anti-multipath fading performance and expand communication distance. Using this test bed, we carried out field tests in two environment. One environment is an office in an non line of sight (NLOS), and another environment is an outdoor in a line of sight (LOS). In this paper, we explain the outline of the test bed, the measurement method, and present the results of the field tests. In the office environment, we measured the performance of each set with a different number of antenna elements. The results show that the dead-spots where communication becomes impossible disappear if the number of antenna elements is more than or equal to two. In addition, a greater number of elements indicates better performance. The total average throughput is 1.6 times as efficient when two elements are used, and 1.9 times when four elements are used. Cold spots where the throughput is slower than 1 Mbps are reduced by 80-90%. In the outdoor LOS environment field test, it is shown that by using four-element smart antenna for both transmitter and receiver, the communication distance reached 1km with an average throughput of 4 Mbps. These results prove that the smart antenna drastically improves the performance of a wireless LAN system, i.e. the IEEE802.11b.