Marc Engels 
Wireless OFDM Systems [PDF ebook] 
How to make them work?

Wireless Local Area Networks (WLANs) experience a growing popularity recently. Where WLANs were primarily used for niche applications in the past, they are now deployed as wireless extensions to computer networks. The increase of the datarates from 2 Mbps up to 11 Mbps for roughly a constant price has played a major role in this breakthrough. As a consequence, an even greater success can be envisioned for the more recent OFDM-based WLAN standards in the 5 GHz band, which offer up to 54 Mbps. At IMEC we have realised this potential already several years ago and have established a successful research programme on OF- based WLAN. In 1995, we started our research on wireless OFDM in the frame of a – operation project with SAIT, a Belgian telecom company. The goal of the project was to establish a robust network for industrial environments. This resulted in a first OFDM chip, supporting QPSK, for wireless networking at the end of the project (1999). 1999 was also the start of an intense co-operation with National Semiconductor Inc., which resulted in a second generation ASIC in 2000. This OFDM processor supports up to QAM-64 and has a more optimal channel estimation algorithm.