The Magic WAND has been a three-year project. The focus has been to develop a wireless ATM based transmission facility that expands the reach of ATM QoS based technology to the ambulant user of premises communications networks. Developed technology was evaluated in realistic user environments.
The WAND project consisted of three major phases. In the first phase, system and component design was undertaken. In the second phase an implementation of the design was produced. The integrated implementation, using mobiles based on portable computers in combination with Access Points serviced by an ATM switch, was to be as close as possible to the targeted functionality defined in the design phase. In the final phase of the project, wireless ATM Access based applications were tested out with end-users in realistic hospital and university environments.
The main objectives of the project were:
1) to specify a wireless, customer premises, access system for ATM networks that maintains the service characteristics and benefits of ATM networks,
2) to demonstrate and carry out user trials with the selected user groups and test the feasibility of a radio based ATM access, and
3) to support promote the standardization, notably in ETSI and ATM forum, of wireless ATM access as developed in this project.
Achievements
The project has during three years period developed both demo and WAND final system specifications. These specifications have been verified and documented with SDL (System Description Language) and MSCs (Message Sequence Charts). WAND final system specifications contain valuable enhancements learned from the implementation of the demo system. Similarly, the new design work on wireless IP with QoS, Wireless Local Loop, Dynamic Channel Allocation techniques, etc. enhance WAND system specification scope to cover all the aspects required exploitation of wireless ATM access networks for customer premises environments.
Despite delays in implementation and integration, the final result was fully integrated system. The peak bit rates measured over the wireless link are up to 16 Mbps. Average delays measured with Ping application show values between 2-5 ms. Retransmissions due to errors over the wireless link create occasional peaks to the delay causing strong variations into e.g. TCP performance.
WAND user trials were successfully conducted at three locations: Tampere, Hildesheim and Ulm. Due to delays in demo platform, the first set of user trials was organised without wireless connection. The focus was on the application usability and conceptual testing of user scenario in fair-guide and medical consultation. The second phase (at Tampere) was performed to complete the study on application behaviour over the wireless link.
In addition, outdoor propagation tests for using a WAND-like system in a wireless local loop scenario where conducted in Mägenwil from Ascom premises and in Zürich from ETH premises. They have shown that such a system can be used over line of sight links of some kilometers when using directional antennas.
The main contributions of the four laboratories of ETH Zürich active in the WAND project were:
· audio and video coding for user applications,
· radio channel measurements and modeling,
· performance evaluation and scheduling in wireless ATM networks,
· development of key components for very high speed wireless ATM.
Further information about the project can be found at the public website:
http://www.tik.ee.ethz.ch/~wand
