wireless data signalling range

[think2]

Hi

I need to signal data from a fixed point in a building to a guy with a cellphone running Java at some other point in the building - could be any type of building, single storey or 50 storeys. We can use WiFi or a cellular phone network but I suspect that parts of the building e.g. the basement, won't get a good enough signal to work. Is there any more reliable way of signalling data and have it come up on a smart phone/ PDA thing.

TIA

 

[gsaldivar]

It's hard to give a recommendation without more detail about your expectations, but speaking in general terms:

If you're talking about a single fixed point and 50 stories, cellular data is probably a good option. Because any method you choose will have some reception issues, the scheme you choose should incorporate some type of confirmation-of-delivery , where the message is held for attempted redelivery if the recipient is unavailable on the network. This would mitigate most reception issues, and ensure that your data is received at the earliest possible moment (i.e. when the recipient appears back on the network).

For large areas where there is no possibility of network reception (basement, etc.) you would want to choose a cellular network that supports the use of subscriber-installed femtocell technology. This would allow you to purchase one or more small transmitters that will extend the providers signal to areas with poor reception.

http://www.wireless.att.com/learn/why/3gmicrocell/

 

[think2]

The situation is validation of a fire alarm system in a new building just before occupancy so it's a one time thing for the building so the femtocell thing isn't really an option because it requires a landline.

Is there any way to send data using two way radios with maybe a stronger signal than cellular networks have?

 

[gsaldivar]

Wow... It seems you have a really specialized application.

One option might be trying to bridge a bunch of WiFi routers together, one per floor perhaps. This method wouldn't require reception of a cellular network, but rather only the next-nearest router. If you tried doing this with a 50-story building, I think that you may run into some issues with getting the data to propagate reliably from one end of the network to the other with so many devices in play. Maybe someone can share some experience with the bridging limitations.

Good luck!

 

[Emulex]

directional wifi routers running at 1mbps can do many miles with a good antenna and aim

 

[skyking]

If and this is a big IF, you had permission to use the interconnects put in by the data people, you could route communication through on that copper. It would take some hardware and setup, it would be a two person gig all the way if I were doing it. Ther would be too many trips up and down to move the other end.
Most buildings will have a basic set of interconnects in place to the Demarc room.
(1) get permission!
(2) look at the diagram for the building and locate the ends of the interconnect runs. Note the type of termination, it will be either a 66 block, a 110 block, or if you are lucky there will be data runs in place. If it is data move to step 4.
(3)go to this site or give sandman a call, he will hook you up with the appropriate adapters to go to 568B
http://www.sandman.com/cabletst.html
(4) configure a couple of routers as needed, one at the demarc room and the other you carry with you. Plug in with adapter in closets on upper floors and take your access point along with you. It may be cat3 but remember, it was certified to 10baseT and will probably hook up at 100 anyway.

 

[skyking]

The situation is validation of a fire alarm system in a new building just before occupancy so it's a one time thing for the building so the femtocell thing isn't really an option because it requires a landline.

Is there any way to send data using two way radios with maybe a stronger signal than cellular networks have?

If you are dealing with a fire alarm system you should have two landlines in place, a primary dedicated line and a secondary. You can also employ the secondary as you wish, since the RJ31X will cut you off if needed.

 

[think2]

One end is a fixed point - the fire panel. The other end is a guy wandering around the building, testing detectors. Two people with walkie talkies are used at the moment. We're trying to see if it can be done with one person. We don't need a fast data rate, just reliability. Usually the signal would have to go up and or out.

 

[ScottMac]

Contact Andrew Corporation, and talk to them about "Radiax" - essentially a distributed antenna made of leaky hardline. It's used a lot for internal paging networks and / or run in elevator shafts, etc. Andrew also has access point / WiFi transceivers to drive it.

Good Luck