Network overview: ViaNET system
The ViaNET system is based on three different products and related accessories: ViaNET Access Point, ViaNET Mobile Terminal and CrossNET server.
The ViaNET system offers several important new networking features. It is practical to view the system as a normal Ethernet based LAN solution, which is built with wireless radio products. End users only need to know about the application level parts like the camera or phone in a moving vehicle. From application level the network is like any other LAN (Local Area Network). Users just need to define the network addresses of the equipment they are using in the LAN. CrossNET server is a centralised management and network configuration point.
The CrossNET server is also a terminating point which provides an interface between the ViaNET network and an external network. Data traffic from the ViaNET Mobile Terminals is terminated at the CrossNET, wherefrom data packets are forwarded to their destination address. Data traffic is bridged between the Mobile Terminals and CrossNET server. Key settings in the network configuration are done with the CrossNET server and Mobile Terminals. Mobile Terminal configuration covers separate roles of both radios and their settings. Access Points forward data packets between the CrossNET server and ViaNET Mobile Terminals.
The ViaNET radio units include versatile radio configuration parameters required for the adjustment and tuning of the radio link connection. The ViaNET Mobile Terminals have four external antenna connectors. These are used to support antenna diversity with two 802.11 radios. Both radios of a ViaNET MT have two antenna ports. As the system support two-antenna solution, the better signal from either antenna port 1 or 2 is then used. Antenna diversity is designed completely into this specific solution. This is an important feature, as the radio coverage and signal propagation characteristics are dynamic and varying in mobile applications. Many indoor access points support only one low gain omni antennas which offer only limited range and coverage. Better signal quality and longer range connections are supported with ViaNET's advanced radio system design. Use of IEEE 802.11g (OFDM) transceivers performs very well in an environment where the signal path changes dynamically. Mobile radio link environment creates scattering and diffractions in the wireless signals, which require the radio solution to be tolerant for multi path fading and complex radio wave propagation environment. The OFDM radios used in ViaNET units have characteristically good tolerance for these potential sources of signal strength reduction and interference.
