Wireless Mesh-Networks for Interconnection ofRemote Sites to Fixed Broadband NetworksFeasibility Study

Kurt Baumannkurt.baumann@switch.ch

TF-Mobility Meeting, Vienna, 18.02.10

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Outline

Feasibility Study- Proposal- Physical testbed

- Technical aspects- Results- Conclusion and further projects

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ProposalThe project investigates the feasibility of multi-hop wirelessmesh networks for connecting sensor networks or otherdevices deployed in remote areas, where no fixed networkaccess is available, to a fixed broadband network.

Distances of (several) 10 km need to be traversed.

The project will evaluate Quality-of-Service parameters such asbandwidth, delay, and robustness that can be expected from asolution, which is based on transmission over multiple hopsand multiple paths.

Project lead: University of Bern, IAM, Prof. Dr. T. BraunIndustry-partners: MeteoSwiss / SWITCH / pcEngines

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Physical Testbed

CTI-Link, area Payerne:Redundant-Link:

1070m 10300m 11500mLink1: Payerne <==> Corges <==> Sur Le Mont <==> University-Neuchâtel

6760m 1000m 14100mLink2: Payerne <==> Belmont <==> La Gotta <==> University-Neuchâtel

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Technical AspectsMesh-Node:PCEngines Alix.3DA board

Core of the Mesh nodes contains500 MHz AMD Geode LX800 CPU,256 MB RAM, 2 miniPCI slots withIEEE802.11a/b/g/h cards, 1EthernetIF, 1GB Compact Flash CardAluminum weather sealed (IP-67)outdoor. Software: Linux distribution,an development of University of Berncalled ADAM( Administration andDeployment of Ad-hoc Meshnetworks)

Two directional panel antennasFrineta, 5.1-5.875 GHz, 23dBi gain,

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Technical AspectsMast:Telescopic mast sideways slottedaluminum (6)Tubes, max. 9 m with tripod

Requirements to the mast type:- Costs- Transportability- Project duration- High acceptance for the landowner

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Technical AspectsPower-Provisioning Nodes:Powered by the electricity grid or solar pannel

2 nodes: UniNE and MeteoSwiss areconnected via lightning protector and PoEto the grid.4 nodes are supplied with electricity bysolar - 80W panel. Power equipment ina aluminum box inside a solar-charger,an acid battery (65Ah, 12V - 10days selfcharging), a lightning protector and apassive PoE

Node (power consumption approx. 3.3 W)on the antenna is connected with a twistedpair cable to the electric supply box.

Network connectivity over Ethernet for onsite maintenance.

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Technical AspectsNode on the rooftop of MeteoSwiss:This node operates as a sensor node, an IP capablecamera.

http://cti-mesh.ch/cgi-bin/smokeping.cgi?target=CTI-Mesh

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Technical Aspects

Route availability to node 6 (IP camera) at node 1

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ResultsFree Space Path Loss Model

Nodexx dm FZr(m) Hmin(m) FSLdB Si(dBm) Pout(mW)

Neuchâtel ⇔Sur le Mont 11500 7.513 9.463 128.47 -77.09 7.277Sur le Mont ⇔Corges 10300 7.110 8.668 127.51 -76.13 7.277Corges ⇔ Payerne 1070 2.291 2.308 107.85 -56.46 7.277Payerne ⇔Belmont 6760 5.760 6.431 123.86 -72.47 7.277Belmont ⇔ La Gotta 1000 2.215 2.223 105.26 -53.87 7.277La Gotta ⇔Neuchâtel 14100 8.319 11.239 130.24 -78.86 7.277

d(m): Distance between two nodesFZr(m): Radius of the first Freznel Zone (60%)Hmin(m): Min of antenna highFSL(dB): Free Space Path LossSi(dBm): Received power level at receiver input

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Conclusion / Further ProjectsView of SWITCH:

Feasibility study is a success story in extending the network Coverage

Locations: In the project, the interconnection of the WMN and the SWITCH fibre backbonewas build up easily at the University of Neuchâtel. As currently no processto get access to the backbone on an arbitrary location is defined and inplace, the backbone access has to be checked and supported individuallyfor each location; that makes it personnel-intensive and therefore costly.

The feasibility study showed that, currently, the network reliability as wellas the data-throughput of the prototype network do not allow providingWMN specific solutions for wireless broadband connections of customerSites.

Follow-up project will allow investigations on the network reliability andthroughput by reengineering the wireless interface driver, routing software,and self-healing mechanisms. Furthermore, the handling of the antenna equipmentas well as the alignment-process of the antenna has to be simplifiedfor the end-users.

Moreover the attractiveness of this service could be enhanced by increased data rates of newer wirelesscommunication standards e.g. IEEE802.11n.

Wireless Mesh-Networks for Interconnection ofRemote Sites to Fixed Broadband NetworksFeasibility Study

Kurt Baumannkurt.baumann@switch.ch

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