EURASIP Journal on Applied Signal Processing 
Volume 2006 (2006), Article ID 18083, 20 pages
doi:10.1155/ASP/2006/18083

A MIMO-OFDM Testbed for Wireless Local Area Networks

Albert Guillén i Fàbregas,1 Maxime Guillaud,2 Dirk T. M. Slock,2 Giuseppe Caire,3 Karine Gosse,4 Stéphanie Rouquette,4 Alexandre Ribeiro Dias,4 Philippe Bernardin,4 Xavier Miet,4 Jean-Marc Conrat,5 Yann Toutain,6 Alain Peden,7 and Zaiqing Li7

1Institute for Telecommunications Research, University of South Australia, SPRI Building, Mawson Lakes Boulevard, Mawson Lakes, SA 5095, Australia
2Eurécom Institute, 2229 Route des Crêtes, Sophia Antipolis 06904, France
3Electrical Engineering Department, University of Southern California, 3740 McClintock Avenue, Los Angeles, CA 90089, USA
4Motorola Labs, Centre de Recherche de Motorola, Espace Technologique Saint-Aubin, Gif-sur-Yvette 91193, France
5France Telecom R&D, 3 avenue des Usines, Belfort 90007, France
6Antennessa, avenue la Perouse, Plouzane 29280, France
7École Nationale Supérieure des Télécommunications de Bretagne, Technopôle Brest-Iroise, Brest 29238, France

Received 15 December 2004; Revised 11 May 2005; Accepted 21 June 2005

Abstract

We describe the design steps and final implementation of a MIMO OFDM prototype platform developed to enhance the performance of wireless LAN standards such as HiperLAN/2 and 802.11, using multiple transmit and multiple receive antennas. We first describe the channel measurement campaign used to characterize the indoor operational propagation environment, and analyze the influence of the channel on code design through a ray-tracing channel simulator. We also comment on some antenna and RF issues which are of importance for the final realization of the testbed. Multiple coding, decoding, and channel estimation strategies are discussed and their respective performance-complexity trade-offs are evaluated over the realistic channel obtained from the propagation studies. Finally, we present the design methodology, including cross-validation of the Matlab, C++, and VHDL components, and the final demonstrator architecture. We highlight the increased measured performance of the MIMO testbed over the single-antenna system.