Introduction

Zusammenfassung

Wireless communication technologies play an increasingly important role in recent years. The GSM telephone network has experienced a rapid deployment within 15 years: starting with the first GSM call in 1991, there are more than 3.5 billion subscribers as of the 4th quarter 2008 [122]. Furthermore, triggered by the rapid deployment for small portable computers like laptops and PDAs, or home applications such as video streaming between a file server and the TV, there is now also a growing demand for wireless data network access. The development of Wireless Local Area Networks (WLANs) started in the middle of the 1990s [120]. The first solutions were proprietary, such as RadioLAN WIN or Lucent WaveLAN computer plug-in cards, i. e. there was no common standard available for the radio interface which ensured that WLAN devices could communicate with devices from other manufacturers. This lack of interoperability prevented WLANs from being sold in large numbers.