Wireless Signal Broadcast Shapes and Device Location

Question

I understand that this might be a broad question, so feel free to make it bleed with edits, but what considerations do I need to make with regards to signal shapes and device locations in a small-medium sized location with these characteristics:

• Mix of office area and dirty manufacturing shop floor in one squarish building (shop floor is roughly 3x the size of the office area, ~120K sq feet total)
• Office building has a mix of open cubicle area and offices / conf rooms around the perimeter
• Building is constructed of primarily steel and cinder block.

I'm thinking of using Cisco equipment if that helps to narrow it down, but am not committed at this point. I would need to keep the cost down as much as possible, but it's understood that reliability trumps staying well under-budget if you get my meaning.

Let me know if there is more I should include in the question!

Answer 1

I've got a similar installation to yours and managed to get good coverage with only four access points in the factory area and two in the office area. They are Cisco 1200 series and are mounted in the ceiling, using POE to facilitate reboots from the ground. Ceiling-mounting helps considerably to get good signal propagation; I've not seen any dead spots and there is a significant amount of interference from welders and other high-EMF equipment.
But, as LapTop006 said, a good survey is key to understanding any unique features in your building - steel curtains, firewalls (the kind that actually stop fires), equipment, power, etc. will all have a large effect on your wireless coverage. You could try setting up an AP temporarily near where you think you'll want one, then go out with a laptop with Kismet, Network Stumbler, or similar and take notes on a map what your signal strength is. Once you've got a good idea, look for weaknesses and see if you can identify the cause. Unfortunately, there will be a lot of trial and error, but with a little planning and lots of testing, you should be able to get reasonable coverage with a minimum of equipment (read: dollars). Another area to investigate would be antennas for the APs - the standard duckies that most come with are good, but an investment in higher-quality larger antennas could save the cost of more access points, saving both money and equipment to install/maintain. Make sure that whatever APs you get have removable antennas and that the connector is a standard (RP-TNC is very common, especially amongst the Cisco crowd)

Answer 2

The only real way to test is to get out there and survey.

In office areas you end up needing 1 AP every ~15M, for really open areas you can get to 30-40M if there's always good line of sight.

Answer 3

I have learned a lot about wireless from MetaGeek and L-com. Knowing what equipment does what and what is good and what is bad goes a long way.