Warehouse Antenna – Wireless Network Design using Ekahau Pro – Distribution Center/Warehouse Part 2

Posted on Posted in Ekahau

Design Scenario # 2 – Warehouse / distribution Center

Designing for wireless a warehouse/distribution center is completely different from designing for a carpeted office space or hospital. 

Enter external antennas!

As with everything wireless:

what are the requirements?”

do you have clean floor plans?”.

“do you have warehouse shelve/rack elevations?

“what kind of inventory do you stock on the shelves, and what materials are they made of?”

You can see how some of the requirements that we used previously are not valid in the “office” space, and some are. The bottom line is, have a baseline set of requirements and continue to build on them as you work on different types of projects or verticals (Retail, Health Care, Education, Enterprise, etc.)


Example scenario…

You – “what are the requirements for the RF scanners?”

Customer: “RF scanners? We do not use RF guns in the office space.”

Example scenario warehouse:

You – assumption “you do not use RF scanners in the office space part of the warehouse, so I will not design for them.”

Customer – “that is NOT correct. We use RF guns in the office space.”

My point is – requirements, requirements, requirements! Gather the customer requirements. Ask questions as many questions as you can.

In my opinion these questions should be asked early in the kickoff call.

Example rack elevation

Reference: https://nationwideshelving.com/advance-storage-products-flow-rack-systems-pallet-flow-salt-lake-city-ut.php


What next?

Requirements, requirements, requirements! Remember that requirements are “dynamic” in nature and will constantly shift in to align with company requirements. 

In some organizations, what was confirmed last week Monday is no longer valid the following Monday. Therefore, it is necessary to be in sync with the customer or stakeholders. This can be done via weekly project meetings.

Now that the baseline requirements have been gathered, you need to understand the warehouse/distribution center environment. 

What does the layout look like?

Is it a co-location warehouse, or is it 100% company-owned? These questions will give you an idea about neighboring access points, interferes, etc. You obviously don’t own the airspace neither does your neighbor :). But understanding what is beyond the walls will help influence your design, AP layout, channels, etc.

I will circle back to a requirement question. “Is this a new warehouse/distribution center or is it existing?” I do this to stress the importance of requirements. Knowing if a site is existing vs. new will allow you to start visualizing/formulating a design. In some cases, requirement gathering will happen over a few days or weeks, especially in a new warehouse build out.


Sample Floor plan for predictive modeling – 65,000 + square feet


  1. Question based on assumption # 1 – is 18 dB per meter to much antennation?
  2. Question based on assumption # 2 – is 6dB per meter to much antennation?
  3. How can I effectively create a “valid” design for this space?
  4. Should I use omni directional antennas in the warehouse/distribution center space (between the aisles/racks)?

The design methodology for office space/Hospitals might not be feasible for manufacturing/warehouse or distribution centers. The next topic might seem trivial, but ignoring the difference will determine if your design works.

Manufacturing – used for creating products. Products will not be stored here for long periods.

Warehouse/distribution center – The finished products from the manufacturing plant will be shipped to the warehouse/distribution center for long term storage.

Why is this important? 

Differentiating between the two “space types” will allow you to select an antenna type. Manufacturing facilities most likely have equipment used for making a product, and once the product is finished, they are placed on pallets and shipped to the warehouse. The manufacturing facility might not contain racks that are 25-30′ high. That is one of the critical items to consider when designing for this vertical.

Warehouses/distribution centers, on the other hand will have a combination of racks that are 25-30′ high, office space, and open areas on the warehouse floor. 

The open areas will most likely be used temporary storage before moving the merchandise to the racks for long-term storage. The open space will be used to stack pallets or park forklifts, robotics, etc.

Why spend time on this nonsense, you might ask? The answer is antenna selection! Antenna selection is crucial and will play an essential factor in the overall design. For example you most likely will NOT use the 13dBi antenna in the office sections of the warehouse. Deploying omni directional antennas is more common for this type of space.

Note: In this blog, I will not discuss installing mounting omnidirectional antennas in the warehouse. Will it work? Yes! Will it work efficiently is the “real” question. I will only discuss what I deploy and what works best based on the requirements.

I like to cover the aisle from the top down – the antenna is mounted between 25 – 40 feet depending on the facility. This provides what I call “controlled coverage” between the aisles. 

The RSSI and SNR will remain consistent regardless of if forklifts are blocking both ends of an aisle. Wireless connectivity fundamentally relies on a constant and reliable connection. You could potentially mount the antenna at the end of the aisles and shoot directly down the path.


Antenna selection

Antenna selection is essential for a few reasons. I’ll outline my opinions here:

  1. Using an antenna from Aruba or Cisco is potentially cheaper when you bulk order equipment and after they apply a discount.
  2. When you use Cisco or Aruba antennas, you do not have to worry about the leads that connect the antennas. Vendor equipment is built to work right out the box. Third-party antennas might require additional connectors which will also increase the overall cost.
  3. Third-party antennas, for the most part, will perform better. Again, that is my opinion and not a fact.
  4. The downside of third-party antennas. If you open a TAC case with Cisco or Aruba, they might require that you install one of their antennas before they assist you in troubleshooting.
  5. Depending on the facility, the antenna type will also influence your mounting options. This could potentially increase the cost.
  6. Third-party antennas might be more expensive.

I’ve used antenna from Meraki, Aruba, and Cisco. I am currently using the Ventev M6130130MP1D0006W – Antenna – 13dbi-4 lead for Aruba or 6 lead for Meraki. The SKU for the antennas will be different. Pay attention to the connector type: RP-SMA vs RP-TNC, etc.

RP-SMA

VS


RP-TNC


The datasheet for the antenna can be found here – https://ventevinfra.com/product/2-4-5ghz-13dbi-wi-fi-directional-antenna-with-4-n-style-connectors/

It is a large antenna, but the RF propagation between the warehouse aisle is phenomenal.


Ekahau Predictive Model for Warehouse/distribution centers

The M6130130MP1D0006W is a 13dBi gain antenna designed by Ventev to provide coverage down the aisles of a warehouse. Depending on the length of the aisles one or two antennas can be deployed.

The M6130130MP1D0006W is available in Ekahau.  As mentioned earlier the antenna is mounted on the ceiling pointing down to the ground via Ventev mount which I will cover later.

Example of the M6130130MP1D0006W antenna is Ekahau.


After all, or most of the requirements have been gathered, the next phase is to start the predictive modeling. However, the basic logic for warehouse design remains true.

  1. Obtain clean/clear floor plans
  2. Obtain measurements via onsite visit (if possible), AutoCAD drawings, or scaled PDFs
  3. Obtain information about inventory, inventory levels, peak times, etc.
  4. Insert the floor plan into Ekahau and scale
  5. Draw in attenuation areas

 In the image below I drew the racks at 18dB per meter and 29’ high. The lower racks were drawn at 6dB per meter. Why? This is an “assumption” looking at the variation in inventory levels. Is it scientific? No but it works for me.


The next step would be orienting the antenna correctly in Ekahau. If this step is missed or done incorrectly, it will severely affect your design based on the antenna type. This is true for Ekahau modeling and the real-world deployment of the antenna. Antenna polarization is essential.

Facts from the datasheet.



M6130130MP1D0006W


Let’s look at the antenna in Ekahau

The two images below show incorrect and correct placement of the antenna. The AP and antennas are identical. What differs here is the alignment / polarization of the antenna. The antenna will provide a narrow beamwidth throughout the aisle. There will be some bleed through aisles as the inventory levels fluctuate.



Note: I applied a “small” offset for the least capable device.

Note: The M6130130MP1D0006W requires (4) leads between the antenna and the AP. I will cover that in a later blog post.

The M6130130MP1D0006W will facilitate the design requirements for the aisles. Let’s look at the open space.


Here is another location that is utilizing the 6 lead version of the M6130130MP1D0006W antenna. The AP vendor is Cisco Meraki

The length of the aisle is 194 feet. As I mentioned earlier, depending on the length of the aisle one antenna will be enough. In some cases you will have to use two.

5GHz coverage at RSSI -65

2.4GHz RSSI at -65

SNR of 25dB for 5GHz


SNR of 25dB for 2.4GHz


If you look closely at the end of the aisle you’ll see that the signal strength from the sidekick’s view starts to decrease. One solution is to utilize a 6dBi wide patch antenna at the end of the aisle. The distance from the end of the aisle and the perimeter of the building is over 90′. The wide patch antenna is also mounted at 40′ similar to the antennas in the aisles.



Adding the wide patch antenna in the open space allows for optimal end of aisle coverage.


SNR for the wide patch antenna




The next antenna is the M6060060P1D43602C from Ventev.


The M6060060P1D43602C will be utilized to cover the open spaces in the warehouse. I do not mount Omni directional antennas at 40’ expecting proper RSSI and SNR at ground level. Omnis also increase the noise floor and create CCI.


Below is the expected predictive modeling coverage of the M6060060P1D43602C antenna – used for open areas

Below is the expected coverage of the M6060060P1D43602C antenna – used for open areas


Note: The office space APs are Aruba AP-535.


Validating the design once it is in production

The M6130130MP1D0006W – the inventory levels empty at the time of the survey and an offset was applied in Ekahau for the least capable client. The antenna is indeed providing coverage down the aisles as expected. Keep in mind that this is at the floor level. The antenna should perform even better at the top of the rack – for example, inventory picking via a cherry picker. 

So regardless of if the station (STA) location in the aisle (close to the AP or at ground level), the client will always have excellent RSSI and SNR within -67dB /25dBm





Let’s look at the SNR of the M6130130MP1D0006W between the aisles -25dB





Now let’s look at the M060060M1D43620C – RSSI -67





Now let’s look at the M060060M1D43620C – SNR 25dB





Validate the office space – RSSI -65dBm




Validate the office space – SNR 25dB



Part 1 – Wireless Network Design using Ekahau Pro Part 1 – Office Space can be found here

Part 3 of the blog post will outline the following.

  1. Ventev antenna mounting options
  2. How to properly mount and orient the antenna

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.