Big mesh network along a sea-channel


Our company has been asked for a solution for controlling outdoor lamps placed along a sea-channel extended for 17Km. Lamp units will be be powered by mean of solar panels/batteries and of data-connected through a ZigBee network.

Units will be placed every 80 m, along two facing lines, on the edges of the channel, distiant about 200 metres.

Each unit will contain a XBee module (probably “Pro” version, but we’d like to know whether standard modules would be enough) and a custom microcontroller board driving lamps and battery charger while obviously talking with onboard XBee module using API mode. RX messages will be primarily targeted to switching on/off onboard lamps, while TX messages purpose will be primarily diagnostic (battery level, battery fault, etc.).

We’d like to know:

  1. What is the right topology? How many routers should we place and where?
  2. Since we’re talking about 450 XBee nodes: what could be weak point of whole system? Should we expect that with so many hops far nodes will be reached by RX messages after a long delay?
  3. Does anybody know about real-world use cases with a mesh network of such dimension?