istics summarised in Table 6-16. Table 6-16: Main Characteristics of the HomeRF SWAP Main characteristics specification TDMA for synchronous data traffic - up to 6 TDD voice conversations. CSMA/CA for asynchronous data traffic, with prioritisation for streaming data. CSMA/CA and TDMA periods in a single SWAP frame. FHSS radio in the 2.4 GHz ISM band. 50-100 hops per second. 2- and 4-FSK modulation deliver PHY layer data rates of 0.8 and 1.6 Mbps. Wireless LAN Standards Although the HomeRF Working Group claimed some early market penetration of SWAP based products, by 2001, as SWAP 2.0 was being introduced with a 10 Mbps PHY layer data rate, the home networking market had been virtually monopolised by 802.11b products. The Working Group was finally disbanded in January 2003. HiperLAN/2 HiperLAN stands for high performance radio local area network and is a wireless LAN standard that was developed by the European Telecommunications Standards Institute's Broadband Radio Access Networks (BRAN) project. The HiperLAN/2 Global Forum was formed in September 1999 by Bosch, Ericsson, Nokia and others, as an open industry forum to promote HiperLAN/2 and ensure completion of the standard. The HiperLAN/2 PHY layer is very similar to the 802.11a PHY, using OFDM in the 5 GHz band to deliver a PHY layer data rate of up to 54 Mbps. The key difference between 802.11a and HiperLAN/2 is at the MAC layer where, instead of using CSMA/CA to control media access, HiperLAN/2 uses time division multiple access (TDMA). Aspects of these two access methods are compared in Table 6-17. The technical advantages of HiperLAN/2, namely QoS, European compatibility and higher MAC SAP data rate, have now to a large Table 6-17: CSMA/CA and TDMA Media Access Compared Media access method Characteristics CSMA/CA Contention based access, collisions or interference result in indefinite backoff. QoS to support synchronous (voice and video) traffic only introduced with 802. 11e. MAC efficiency reduced (54 Mbps at PHY = ca. 25 Mbps at MAC SAP). Dynamically assi