Virtual Subcarrier Assignment (VISA) for Spatial Filtering of OFDM Signals

Shinsuke HARA
Yunjian JIA

Publication
IEICE TRANSACTIONS on Communications   Vol.E89-B    No.11    pp.3055-3064
Publication Date: 2006/11/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.11.3055
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
Keyword: 
OFDM,  null forming,  multiple antennas,  space division multiple access,  

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Summary: 
In this paper, we propose a novel spatial filtering technique for orthogonal frequency division multiplexing (OFDM) signals called "VIrtual Subcarrier Assignment (VISA)." Here, virtual subcarrier is a subcarrier which is not used for data transmission. When a wireless terminal is equipped with multiple antennas, VISA can easily achieve a space division multiple access (SDMA) by assigning a different spectral position of virtual subcarrier to a different user. To realize VISA in an already-existing OFDM-based wireless local area network (WLAN), we discuss an antenna weight control method in the preamble of a signal burst format designed for the IEEE802.11a standard and evaluate the bit error rate (BER) performance in typical indoor wireless environments.