The triumph of intelligent multipoint-to-multipoint wireless mesh architecture

The world's longest wireless network based on mesh technology has been deployed in Thailand. The network, built by an American company Firetide, covers a distance of 372 km. It has been conceived as a kind of a gift from Thailand’s Royal Irrigation Department to the 84 year old King of Thailand, Bhumibol Adulyadej. The network is to provide images of the floodplains of the river Chao Phraya. Due to his age, the king is no longer able to oversee the monitored areas in person. The implementation of such a gift turned out to be technically challenging.

The total cost of the world's longest wireless mesh network is about 2 million USD. However, this sum of money is not large considering the fact that during the last monsoon season the network gave the chance to save hundreds of people from flooding. The Thai network belongs to the group of early warning systems for floods.

The images from the cameras are available on the Internet at this address.

Google Maps application provides information on the location of each camera.

 

 

The entire network has been built based on mesh technology. The main advantages of this type of network architecture include auto-configuration and full redundancy in the case of a node/link failure. The latter feature is guaranteed by an automatic change of the route of data packets, which is particularly important in so large and responsible systems.
The main components of the network are 64 Firetide HotPort 7020 wireless mesh nodes and 27 Panasonic PTZ WV-SW395E cameras. The distances between nodes range from 20 to 45 km. The total throughput of the network is as much as 240 Mbps, with node-to-node latency below 1 ms.

High throughput is achieved by the use of Firetide HotPort 7020 mesh nodes, compliant with 802.11n standard and implementing MIMO multi-antenna technology, with 40 MHz wide channels. The routing of the frames is based on proprietary AutoMesh mechanism, based on the 802.11s standard for wireless mesh networks approved in the last year. [source: firetide.com]

Last year's approval of the 802.11s standard can accelerate the popularization of wireless mesh technology. Until now, mesh networks were mostly implemented as experimental projects, not having much in common with the commercial market. Today, in addition to the large-scale undertaking in Thailand, some more "ordinary" projects are carried out, such as the city video surveillance system in Altanta, with 110 cameras. Time will tell whether mesh technology will be more popular on European markets.

Wi-Fi in single-family house

The user who has Internet connection in single-family house, usually would like to have possibility of using the Internet in various parts of the home or even in its close surroundings like garage or garden. To reach that goal, the perfect solution is use of a wireless network (WLAN) operating in 802.11b/g standard.

In the case of difficulty with building cable installation, the wireless network can also solve the problem with connection of a greater number of household computers to the global network. Depending on the way of providing the Internet to the house, there may be used different variants of installations.

I - Internet provided by cable television operator via cable modem with Ethernet output, or by local ISP using Ethernet cable.

II - Internet access via ADSL technology.

III - Internet provided wirelessly with the use of the set: directional antenna and wireless card in the computer. At least two devices have to be used. Firstly, we have to connect access point working in AP Client mode to a directional antenna.

IV - wireless access. Some Access Points have been fitted with a very useful function named Wireless Routing Client, which enables us to configure wireless port as WAN port that is normally found in any router.

It means that the wireless connection can be shared with built-in router by its LAN ports. The advantage of such configuration is compactness - one piece of equipment that performs the role of two devices. The solution allows to create our own configurable subnetwork that can be well protected from unauthorized access.

Tips for TV-Sat installations

Development of television and telecommunications techniques promotes quick spreading of modern antenna installations just like in the past the common use of electric devices extorted careful designing of electric installations.

Some advice for all who would like to do such installation:

1.Place and way of mounting the antennas

Most of damages in antenna installations are the result of collapse of improperly fixed mast or breaking badly laid cable lines. Nowadays, the most popular solution is clamping the antenna mast to a chimney. Masts can also be fixed with wall brackets. Satellite dishes are usually fastened on separate masts. Antenna cable should enter a building already on the roof.
A WLAN antenna has to be mounted the way guarantying mutual visibility with the counterpart (usually of the Internet provider).

2. Kind of installation (pass-through, star-shaped, mixed)

Currently the pass-through installations are not preferred, especially in larger systems. Star installations are more universal and more resistant to interferences induced by connected receivers. They are used both for distributing terrestrial and satellite programs (multiswitch installations).

3. The Method of laying cables
In new office blocks and even apartment buildings cable trays become more and more popular solution for placing electrical, computer, telecommunications and RF installations.

There should be planned main vertical conduit from the basement to the attic, with possibility of leading branches on every floor. Such layout will allow to implement modern installations, change location of main devices etc. It is not recommended to lay unprotected cables just under the plaster. Each cable has limited life and can also be accidentally damaged (e.g. when drilling holes in the wall). The exchange would be extremely difficult.

If the installation is to be laid traditionally, conduit tubes should be applied.

More informations: http://www.dipolnet.com/some_tips_and_hints_dodatek.htm