I'm currently working on the planning/budgeting phase of a new production facility that includes a 165K sq./ft. warehouse area (roughly 400' x 400') with high racking and 13 aisles between the racks. Warehouse workers will be scanning pallets in/out using forklift mounted scanners. I was leaning towards MR46E the MA-ANT-3-F5/6 patch antenna. In previous, albeit smaller warehouse builds, we'd put an AP at the end of each aisle staggering the AP location (top or bottom) every other aisle. My big question is will that arrangement still work in the larger space? Would the signal reach down the entire aisle or would I need to double up in the aisle?
There's certainly pro's and con's of both approaches. Generally wall mounted will reduce the number of APs required but if the walls are too close to the end of the isles you won't get a lot of overlap.
Ceiling mounted uses more APs, and they generally are installed with clear line of site between them with little spacing, meaning you get a lot of CCI and ACI.
With forklifts moving up to 15kmh, overlap is crucial for roaming. This can be problematic to achieve with floor to ceiling racking.
If you can wall mount, and alternate the APs between the opposite ends of the isles you may get a good result.
>we'd put an AP at the end of each aisle staggering the AP location (top or bottom) every other aisle.
By Google's calculation, that is an Isle 122m long. I think the results will be crappy.
I think I would go with ceiling mount, with the APs being 20m, 60m and 100m along from the end of each Isle (so 3 APs per Isle). At 4 APs the coverage would be quite rich.
Do your scanners have the option of taking an external antenna? If so, you could put an actual antenna on the top of the forklift pointing back up to the roof. Or even a simple high gain Omni.
Another interesting twist would be if you could get Ethernet-based scanners, and then put an AP on each forklift (so the forklift units would act as a wired MESH repeater node). Never tried that myself.
3 ceiling mounted APs should get you the coverage for 120m long isles., but you will not get any overlap at the end of the isles, so the client may not be able to select the next AP in time to roam cleanly.
If you can get higher gain on the client side all the better.
At the end of the day, you may have to go onsite and try a few different scenarios to check coverage, and it may never be perfect.
@PhilipDAth Not a good idea with the AP. AP to AP mesh is generally not designed for roaming. However, a wireless bridge, which is in effect a client with an ethernet output might help.
The length of the aisles is what concerned me from the get go as we've never had a location this large previously. The forklifts use Honeywell Thor mobile computers and do have an external antenna on the top of the vehicle. In existing warehouse locations we have good results with those units.
Just wanted to say thanks to all for the comments. Keep the info coming. We do have a vendor that we use that specializes in warehouse scanners and wifi and they will be engaged once all the initially planning is completed. The 3-4 APs per aisle is the info is pertinent for the budgeting process. Now I need to take this info an extrapolate for the smaller raw materials warehouse area and the production machinery floor.
I have succesfully installed narrow patch antennes on MR46E's for aisles that are about 90m, however 120 would need another ceiling mounted omni antenne AP near the end of each aisle.
The advantage of using the narrow patches are you will have fewer roams while driving in the aisle.
If you are eye'ing 5 GHz coverage I would strongly advise against depending on coverage through racks unless they will always have very light materials that signals can easily traverse.
Alternatively you can still go with ceiling mounts but using patch antennes pointing straight down to reduce CCI between AP's and still have strong coverage on the floor but then you'll probably once again need 3 AP's per aisle.
The indoor antennes like the narrow patch have a hidden extra gain that you will need to take into account.
I fell over this (per antenna element gain) on the datasheet and that cost me 2 dB's of power I could not send due to regulatory restrictions.
The narrow patch has a gain of 10.8 dBi on the 5 GHz band (per antenna element), since you have an MR46E you need to add another 6 dB gain to that, so your actual gain would be 16.8 dBi in that case. So if like in my case if you were to use channel 36 through 64 I would living in the EU, I would be limited to 23 dBm EIRP which means my transmit power is no higher than 6dBm!! So in that case I had to go to channels 100-140 to have 30 dBm EIRP which made the Tx power maximally be 13.2 dBm.