Wireless Local Area Networks (WLANs) are experiencing a growing
importance recently. Whereas 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 that offer up to 54 Mbps. At IMEC we have realized this potential
already several years ago and have established a successful research
program on OFDM-based WLAN. The program resulted in an operational
prototype of a 5 GHz OFDM system. The longer term goals of this program
are to extend the indoor range of the WLAN systems up to 100 m and to
increase the capacity above 100 Mbps. Driven by these goals, Patrick
embarked on the usage of multiple antenna techniques and, more in
particular, Space Division Multiple Access (SDMA) for WLAN as the topic
for his doctoral research. During this research, key contributions were
made towards making SDMA for WLAN a reality. To name a few: A basic
scheme for combining OFDM and SDMA was proposed. Also realistic
non-linear detection methods were developed. These me- ods achieve a
high implementation efficiency, by exploiting the p- allelism of the
data model and the frequency-selectivity of the pr- agation channel.