 the vicinity, Authentication with one or more target access points, Reassociation to establish a connection with the target access point, and Pairwise temporal key (PTK) derivation and 802. 1x based authentication via a 4-way handshake, Wireless LAN Standards leading to re-establishment of the connection with continuous QoS through the transition. A key element of the process of associating with the new access point will be a pre-allocation of media reservations that will assure continuity of service - a station will not be in the position of having jumped to a new access point only to find it is unable to get the slot time required to maintain a time critical service. The 802.11k and 802.11r enhancements address roaming within 802.11 networks, and are a step towards transparent roaming between different wireless networks such as 802.11, 3G and WiMAX. The IEEE 802.21 media independent handover (MIH) function, which is described further in the Section "Network Independent Roaming, p. 347", will eventually enable mobile stations to roam across these diverse wireless networks. MIMO and Data Rates to 600 Mbps (802.11n) The IEEE 802.11 Task Group TGn started work during the second half of 2003 to respond to the demand for further increase in WLAN performance, and aims to deliver a minimum effective data rate of 100 Mbps through modifications to the 802.11 PHY and MAC layers. This target data rate, at the MAC service entry point (MAC SAP), will require a PHY layer data rate in excess of 200 Mbps, representing a fourfold increase in throughput compared to 802.11a and 11g networks. Backward compatibility with 11a/b/g networks will ensure a smooth transition from legacy systems, without imposing excessive performance penalties on the high rate capable parts of a network. Although there is still considerable debate among the supporters of alternative proposals, the main industry group working to accelerate the development of the 802.11n standard is the enhanced wireless consortium (EWC) which published Rev 1 of its MAC an