My first project at Cisco was a wireless site survey at a large hospital complex. The hospital wanted a new 802.11n network with CleanAir APs and the ability to track hospital equipment, make Vo-Fi calls and provide guest access for devices like the iPad. The scope was to survey an estimated 3 million square feet of the facility, which wasn’t even all of the buildings! My retail background consisted of either stores or distribution centers, mostly with fairly large square footage, so my first thought was this shouldn’t take long. What is 3 million square feet, when an average distribution center was 1.5 million square feet?
What didn’t occur to me initially, but did very shortly after looking at a floor plan, is the huge difference in the purpose of the buildings. For starters there are a lot of rooms in a hospital, where as in retail there is primarily just large open spaces. Having to walk in and out of room after room, really adds a lot of time to a survey. Additionally many of the rooms have been re-purposed over time to meet the changing needs of the hospital. For example, rooms now used as administrative or doctor offices were at one time used as isolation rooms for patients, or various other uses that make RF propagation less than ideal. Another challenge was restricted pharmaceutical areas where badge and key access is tightly controlled. This doesn’t necessary pose a challenge in terms of providing coverage, but it does when you are walking your survey and you suddenly find yourself locked out of a room!
After many trips to the hospital and countless number of hours roaming hallways and going in and out of room, I have found that a few things have become almost second nature when I am getting things prepped or planning for a return trip. Below I have a few things that might help WLAN Engineers when planning for their next survey project. While none of these are directly related to the finer technical points of a survey, like configuring your survey APs power level importing floor plans into tools like Air Magnet, they will make life much less frustrating!
Make sure you have access to every single room you may need to get into
It’s a real bummer when you are really humming along in your survey only to be interrupted by a locked door that you can’t get into. Make sure you get a set of master keys or full badge access. If this isn’t possible, try to make arrangements with the customer for someone to escort you around that does have access. The only thing worse than a locked door, is badge access that is only good for normal business hours when you are surveying at night!
Good, accurate and updated floor plan drawings are a must
Some of the things I ran into that made life difficult were sub-par drawings of the floor I was working on. In some cases the drawings didn’t have doors or had green wall lines. If your heat map shows up green as good, then it’s a little hard to see the walls if they are the same color. Also helpful is using an actual CAD drawing since JPEGs just don’t cut it when you need to zoom in and move around, as they tend to distort.
Scale your floor plan accurately
If your drawing isn’t to scale then your propagation assessment will be way off, leading to inaccurate data. Keep in mind being off a few inches or centimeters can become several feet if not properly scaled. In large buildings using doors to scale the floor isn’t a good idea, because of how small they are in relation to everything else. One of the tools I found really slick in finding distance is a range finder. These can be relatively inexpensive, but if you don’t have one of these, you can count ceiling tiles. The average ceiling tile square is typically 2×2 feet.
Pack extra batteries for APs and computers
It’s extremely frustrating when your AP or survey computer shuts off because the battery runs out of juice in the middle of your survey. Charge your gear during breaks and keep a second fully charged battery with you to keep your day from ending prematurely.
Invest in the right equipment
Unless you have the arm strength of Arnold Schwarzenegger, odds are you going to want to have something light and easy to carry around. In the past I have used carts to set my laptop on, but smaller spaces aren’t always accommodating to this setup. I suggest a tablet with plenty of CPU power, or I have heard Macbook Airs work well via Twitter. Pay attention to the available connectors, many newer tablets and computers don’t have a PCMCIA slot these days and instead use an express card slot. keep in mind the Cisco CB21, assuming that is what you are using, doesn’t fit into the express card slot. This means obtaining an adapter, which usually just gets in the way, and pops out at inconvenient times.
This is just my short quick list of things to keep in mind. Please feel free to add things you have on your list in the comments field!