Wireless Between the rack in Warehouse

Unanswered Question
Jul 2nd, 2012

Hi All,

I wonder if someone can help me in this, we want to have full wireless coverage in a big warehouse (120mx90m) and 15 meter Height that will be having big racks (14 meters height) and 2 meter between the racks and the rack itself is 1.5 meter (2 rack back to back), now we will be having scanners and we need to make sure the wireless is covering everywhere.

Where is the best place to put the AP, Ceiling ?

How Many APs per row ? each row will be around 60 meters length.

Is AP 1252 a good choice  ?

The scanners are a/b/g

What i'm thinking of is to put 1  AP per row mounted on the ceiling and antennas facing down because it is hard to mount the APs between the rack because of the automated racking system.

Thanks in advance for the advice.

I have this problem too.
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Scott Fella Mon, 07/02/2012 - 08:59

You really need to have a site survey done to truly tell you where the AP's should be placed.  Every environment is different due to materials on the racks, interference, etc.

Where is the best place to put the AP, Ceiling ?

Usually can be mounted to the rafter or beam or you can drop down the AP from a conduit to at least the minimum clearance you need.

How Many APs per row ? each row will be around 60 meters length.

Site Survey is your best answer

Is AP 1252 a good choice ?

You can also look at the 1260, 3502e or 3602e (requires 5508, 2540 or WiSM2 running 7.2 code).

Leo Laohoo Mon, 07/02/2012 - 16:42
Is AP 1252 a good choice  ?

Depends on how you are planning to power up the 1250.  This model has a powerful radio but at a "cost" of higher PoE requirement to operate fully.  The 1250 will work optimally if powered with 20.0 w PoE.

Where is the best place to put the AP, Ceiling ?

Ideally, 10 feet from the ground and hopefully on a non-reflecting background.  For example, the WAP is NOT installed on a metallic surface.   Position the WAP in the middle of the aisle (width).

How Many APs per row ? each row will be around 60 meters length.

Site survey will be the best method of determining this.  Without one, I'd consider 1 WAP every 15 metres.

The scanners are a/b/g

That'll be trouble.  Make sure the scanner DO operate at a/b/g because alot of scanner currently in the market will operate in 802.11b only even though the box says it'll work in a/b/g.  Get one for evaluation and don't listen to the marketing people.  I've seen alot of people who didn't evaluate only to find that they've deployed 802.11n WAPs when they could've just deployed 802..11 a/b/g WAPs (like the 1240) instead.

Consider the following WORST-CASE scenario for poorly written wireless codes:

1.  Operate in the SLOWEST data rates of 802.11b;

2.  OPEN authentication or PSK only; and

3.  Broadcast SSID must be enabled at all cost. 

Going back to your previous question about the choice of WAPs, get ready to put the 1240 in your options as this could be your cheapest option.

alienson13 Mon, 07/02/2012 - 21:54

Thank you guys for the answers it really helped, but the problem is the racks are not ready yet and no time for a site survey since theyn need everything done at once :S, the racks are all metal so either to place the APs on the ceiling which is 1 meter higher than the racks or place the APs on the racks .

I have confirmed the scanners are a/b/g I have the specifications for them.

so Ceiling mount with 1 meter height difference is not a good idea right ? any other way ?

Thanks again

Leo Laohoo Tue, 07/03/2012 - 18:24
I have confirmed the scanners are a/b/g I have the specifications for them. 

Did you "confirm" by testing them or did you confirm from technical-publications-written-by-the-marketing-team?

alienson13 Tue, 07/03/2012 - 22:04

The Scanners model is:

Motorola MC9190G Industrial Class   Mobile Computer

According to the specs it is a/b/g, if it didn't work with both I can simple ask them to take those back and no money for them

According to your recommendations guys now I have 2 choices:

1- using 1240 APs, putting 1 in a row and 2 in the 2nd and so on.

2- Putting 3500e in each row and hope it works fine, but this i don't really support it, all the scanners are a/b/g and won't use the N BW so why putting expensive AP with huge capabilities for a/b/g !!

Right now in the warehouse there are 1142 APs on the walls pointing inside the warehouse and without the rack the coverage is really good, these might help once the racks are put in place to cover the serrounding areas and little near to the begining of each row, correct ?

I will check for the safety walk areas to see if we can use them, thanks for the idea.

Leo Laohoo Wed, 07/04/2012 - 14:45
1- using 1240 APs, putting 1 in a row and 2 in the 2nd and so on.

Hold on.  I didn't say 1 per row (1 row is approximately 60 metres).  

I recommended that 1 per 15 metres in a row. 

Site survey will be the best method of determining this.  Without one, I'd consider 1 WAP every 15 metres.
alienson13 Sat, 07/07/2012 - 23:40

Hehe no worried I know you didn't say that, I just want to reduce the number of APs.

1 AP per 15 meters this is for 5 GHz right ?

Leo Laohoo Sun, 07/08/2012 - 01:29
1 AP per 15 meters this is for 5 GHz right ?

Yes.

Here's the thing, anyone can argue that with 2.4Ghz you can deploy the WAP double the range.  This will depend entirely upon whether or not you can disable the lower rates.

I mean, you can push 25 metres per WAP with 1 Mbps rates enabled.  You just have to test if the scanners can support this.

Scott Fella Wed, 07/04/2012 - 09:43

1- using 1240 APs, putting 1 in a row and 2 in the 2nd and so on.

That might work, but you will need to verify once the racks are up and there is product on the racks

2- Putting 3500e in each row and hope it works fine, but this i don't really support it, all the scanners are a/b/g and won't use the N BW so why putting expensive AP with huge capabilities for a/b/g !!

The 3500's and the 3600's not only support N, but CleanAir, etc.  They also have a better antenna pattern than the older AP's.  They also support being mounted higher due to their antenna pattern.

1140's mounted vertical will give you more vertical coverage than horizontal.  Maybe mounting the 1140s on these brackets at 20' might help: top item

http://www.oberonwireless.com/hard-lid_wall-mounted-access-point-enclosures.php

alienson13 Wed, 07/04/2012 - 22:00

Thanks a lot Scott

Regarding the Antennas thing, I can see that both 1242 and the antennas for 3500e has lot of options for ceilling mount or pillar mount and the patterns are the same for the 1242 antennas and the 3500e except the MIMO thing, this will me a big differenece ? since you have mentioned that the 3500e antennas are better but I can see similar antennas (as below next)

Last thing, which antenna to choose, the one that connects to 1 connector or the 2 elemnts antennas are better ? the 1 connector Antennas (which looks like a big stick)) has more gain:

for the 1242

AIR-ANT1728 or AIR-ANT24020V-R=

for the 3500e:

AIR-ANT1728 or AIR-ANT2430V-R=

And should I use 5GHz band or 2.4 ? I know 5 is better for the amount of channels but has less coverage than the 2.4 and will require more APs, I'm thinking of using both anyway but has to configure the scanners for 1.

Scott Fella Mon, 07/02/2012 - 23:48

Usually a good practice is limit the height to around 30 feet. In situations like a warehouse you have to make excuses in order to provide coverage. The newer APs have a better down tilt pattern. Using a 3500e or 3600e might work better in your situation due to the height. One thing to consider is that there are always areas (safety walk areas) that can have a lower clearance than in between racks. You can always drop an AP down in those areas to provide better coverage in those low areas. Usually you will have exit signs, etc dropped down low which you can reference.

Sent from Cisco Technical Support iPhone App

alienson13 Sun, 07/08/2012 - 22:05

For the Antennas, What do you think of the below Antennas, are they good:

For Ceiling Mount:

AIR-ANT5140V-R=

AIR-ANT2430V-R=

For Side Walls Mount

AIR-ANT2460NP-R

AIR-ANT5160NP-R

the Ceiling Hight is 15 Meters, the mentioned Antennas will work fine or I need more powerfull (which Cisco doesn't have unless I get 3 antennas for each radio omni)

Thanks a Million for the advice

Ruben Miranda Wed, 02/04/2015 - 05:36

I am in pretty much the same boat as you were 3 years ago. 

What I don't see in many of these posts is a follow up,  post deployment, which would greatly benefit anyone using these forums later on.  I would like to know what the final working design of your warehouse was.  There does not seem to be a way for me to message you so hopefully you will get this.  My warehouse has lanes that are 6.5' wide and 300' long with a 50' ceiling and 8 feet of steel racks with frozen products stacked 50' feet high on either side of any lane.  Problem is,the warehouse is just an open space at this point so a survey would not give me all the information I need. 

Thanks!

Scott Fella Wed, 02/04/2015 - 06:22

I have had to work on many of these types of warehouses, even when the isle is smaller with unmanned trucks.  I have used AIR-ANT2544V4M-R= in the isle but had every 3 isle staggered, so that signal might propagate to the adjacent isle or other isle.  There is really no other way I think of doing this and it seems to work fine.  I have also used path antennas, as long as the wall is close to the isle, or else you get a lot of bleed.  This all depends on the product in the racks, so when I test, I will find an isle that is almost or at 100% filled and look at attenuation.  Then you have to create a sample of the ap placements and mimic that to the other isle.  The reason for this, is that if product moves to an empty location, you know that you will have coverage.  Yes you will have a lot of overlap if rack are empty, but you want to ensure that the scanners and other equipment being used will have a wireless connection.

-Scott 

Ruben Miranda Wed, 02/04/2015 - 09:49

Hi Scott, I looked at the AIR-ANT2544V4M-R=.  So you mounted it to the ceiling and placed one in every third isle? So it covers 2 isles? what about the length of the isle? how much coverage do you get?  Mine are 300 feet long.  Just trying to get an idea as to the number of AP's I will need.  

One of the heatmaps I received shows an AP in every other isle near the top end of the isle, and another ap near the bottom but in the adjacent isle.   So, the AP's at the top might be on odd numbered isles and the AP's at the bottom (almost 300 feet away) would be on the even numbered isles sort of like a V shape that repeats itself for the width of the warehouse.  That's an expensive antenna, is it really much better than an internal?  I'm confused as they are both omni directional.

Thanks

 

Scott Fella Wed, 02/04/2015 - 11:20

I might place 2 or 3 depending on the length of the row. But the adjacent and the next isle over would be staggered. Now this works in most clients of mine when performing a site survey, but I have seen signal degrade two rows down. This is why you need to validate the signal so you can understand the attenuation. I have worked on coverage issues also where the customer decided to locate access points using their knowledge of their existing facilities and found out that signal didn't propagate as well as they thought. Testing signal through produc will get you enough info as to how many access points in an isle you need and where you can place them. 

-Scott

George Stefanick Wed, 02/04/2015 - 07:19

Warehouses can be tricky. One day they are at full capacity then next the are half empty. So stock cheese while other stock little widgets, all have a play in how RF propagates. 

 

One me thing is certain. Manage you cells. You direction antennas to lessen CCI. Use small power or RRM. Try and use 5 ghz, avoid 2.4 due to lack of channels. 

 

Test your clients and firmware for roaming behavior.

Ruben Miranda Wed, 02/04/2015 - 09:53

That sounds like good advice. I guess this is where Scott's advice makes sense, plan it for when all shelves are full or at their most challenging which is better than planning with empty shelves. All I can do at this point is have some extra wire left on the beams in each isle in case we need more access points.

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