FPGA Implementation of Eigenbeam MIMO-OFDM for Wireless LAN and Its Experimental Performance

Takeshi ONIZAWA
Atsushi OHTA
Yusuke ASAI
Satoru AIKAWA

Publication
IEICE TRANSACTIONS on Communications   Vol.E89-B    No.12    pp.3233-3241
Publication Date: 2006/12/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.12.3233
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Software Defined Radio Technology and Its Applications)
Category: 
Keyword: 
software-defined radio,  field programmable gate array,  MIMO-OFDM,  eigenbeam,  wireless LAN,  

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Summary: 
This paper describes the experimental performance of eigenbeam multi-input multi-output with orthogonal frequency division multiplexing (MIMO-OFDM) systems as measured in a testbed implemented with field programmable gate arrays (FPGAs). The FPGA-testbed, characterized by the software-defined radio (SDR) technique, offers 1/5-scale real time signal processing. Extensive experiments on the testbed confirm the basic operation and performance of eigenbeam MIMO-OFDM with quadrature phase-shift keying (QPSK) and 16 quadrature amplitude modulation (QAM). From the packet error rate (PER) performance, we confirm that the eigenbeam 16QAM/MIMO-OFDM scheme with permutation matrix and three transmit antennas (Mt=3) drastically improves the required carrier-to-noise power ratio (CNR) by approximately 5.6 dB over the scheme without eigenbeam with Mt=2. Furthermore, to determine the impact of Doppler frequency fd, we focus on the transmission interval between the MIMO channel estimation and data transmission. To suppress the required CNR degradation to within 1.5 dB, it is found that the eigenbeam 16QAM/MIMO-OFDM scheme with permutation matrix and Mt=3 permits a transmission interval of approximately 68.5 ms when fd=1 Hz for a 1/5-scale model.