WiMAX RF Planning....Seriously!!

I have seen numerous discussions on RF network planning on this site, and some of the recommendations are a little scary, given the recommenders do not actually inquire into the project scope. I’ve been designing RF networks (giant and small) for 19 years, and will throw in my two cents, for what it’s worth.

One of the best planning tools on the planet (no pun intended) is Planet EV. It only cost $18K, so I'm not sure what these people’s actual backgrounds are that are quoting $100K+ for a professional tool, it’s absolute total nonsense. GIS data is a fraction of the tool cost, unless you are doing VERY large projects. For instance, one U.S. state, it doesn't matter which, is $2K (30m resolution)for clutter, terrain, and all vectors.

In order to buy and use the tool, you NEED an RF-electrical engineer to run it, no exceptions. It is a serious piece of SW that requires in-depth channel modeling, stochastic, link budget, and electromagnetic experience.This is where it get's expensive, RF engineers are very proud of themselves and they love money!

If you’re looking to deploy one or two sites, you’re probably going to spend $100K-$200K CAPEX, so prudence dictates spending the money to outsource the RF design ($2K-3K); or, go get some cheesy, free RF tool, per recommendations on this site, and take a swag at it; but I am telling you from experience, these tools are basically awful, they do not take clutter into account, among many other variables that are very important. Beware: they are not accurate at all. You might as well draw a circle on a map and pray.

Draw a circle on a map and pray: you can find numerous link budgets on the web, just use their cell radius. I’ll post one I designed for a client; I take no responsibility for its use. Note that they are quite pessimistic (conservative) because they rigorously provide service at cell edge (90%), needed for mobility and major player's customer expectations. This is the method commonly used for paper (Excel) designs, for crude financial planning, not actual network designs.

If you're planning to design a larger network (6 or more sites), my opinion (for what it’s worth) is that you’re crazy not to use a professional planning tool, it’s a fraction of the network cost (CAPEX/OPEX), not to mention the spectrum cost. With an experienced RF engineer and drivetest data (or tuned models), it will tell you to very precise levels where you have coverage (indoor and outdoor), where you have 64QAM vs. 16QAM vs. QPSK (i.e. capacity vs. service area), number of households/business’ in specific service levels (via traffic spreading and modulation type service areas), which sectors are the best serving, how to design the fractional frequency reuse schema (mobile WiMAX), and on and on and on…..

The reason legit organizations use this method is that it pays for itself many, many times over. If you don’t use it, it’s pretty much a Mickey Mouse design (no offense to Mickey).

Kind Regards,

John