wireless ATM (WATM)
WATM (Wireless ATM) is an initiative within the ATM Forum to develop specifications for Asynchronous Transfer Mode (ATM) wireless transmission. This group has been working since mid-1996 and is investigating the technical possibilities. The goal is to realize the transmission of voice, data and video over ATM wireless links using both satellite links and microwave directional radio.
In Europe, this development is being supported by the European Commission within the framework of a number of research projects. The focus here is on base stations and wireless access to ATM fixed networks. European projects in the "Advanced Communications, Technologies and Systems( ACTS)" program include in particular the "Magic Wireless ATM Network Demonstrator" project (WAND), the "Wireless Broadband CPN/ LAN for Professional and Residential Multimedia Application" project and the "System for Advanced Mobile Broadband Applications" project (Samba). All projects have different technical approaches in terms of modulation techniques, media access and bandwidth allocation.
Wireless ATM, as understood by the projects, builds on fixed ATM networks that use access points(APs) to provide wireless connectivity to mobile terminals(MTs). Thus, the access point is the base station of the ATM wireless network and the MT is the mobile station. The AP stations are directly connected to the ATM switches of the ATM network, and these switches have appropriate mobility support. The base stations each serve a radio cell with a range of 30 m to 50 m. Transmission takes place in the C-band at 5.2 GHz (WAND project). The transmission speed of the AP station is 20 Mbit/s at the specified distance and can be dynamically distributed to the various mobile terminals. The mobile terminal (MT) is connected to the AP station as long as it is within transmission range. The logon and logoff of a mobile terminal from the AP station is performed in a procedure similar to that for GSM networks.