Point-to-point/multipoint last mile wireless considerations

Last Mile Wireless
The term last mile wireless is a bit deceptive as it can be much more than a mile. It is also called WiMax and 802.16. It generally refers to relatively short distance point-to-point / point-to-multipoint secure wireless connections between buildings and/or a service provider and their customers.

In this article I will be focusing on building to building connections.

Many businesses have run into the issue of having more than one building or facility that needs to be connected on the same network. The distances covered are more than a standard access point can handle and hardwiring is expensive and sometimes impossible. This is when last mile wireless becomes attractive.

Point-to-point vs Point-to-multipoint
A lot of the lower end and consumer WiMax stuff is straight point-to-point. That makes for a nice cheap plug & play set up, that is their big selling point.

Point-to-multipoint means you have to set one up as the base station and the other(s) to being subscriber units. Sometimes the differing units are identical and can be switched to one or the other with a relatively simple web interface. This makes for much easier future expansion and you can have an extra unit on hand in case one end or the other goes bad.

Planning
No one likes to think of equipment failure, but a wise administrator takes this into consideration before the purchase order / requisition is even written. It only makes sense to choose a set up that can be replaced piecemeal style rather than redoing the entire setup, especially if the locations are several miles apart.

With professional level point-to-multipoint setups, generally the only decision is whether you want to install all-in-one panel style units or ones with external antennas. The panel types are nice because there are fewer connections to go wrong. But sometimes you will need an external antenna for omnidirectional applications, that is when you have more than one subscriber unit that needs to be connected to a centrally located base station.

Picking the right equipment
You can save money in the long run by purchasing better equipment off the bat than opting for cheaper products. The better ones will literally last you for many years, I doubt the cheaper units can claim that.

Installation
Unless you are skilled at such things, it is best to let professionals handle the antenna installation. Keep in mind, depending on your location(s), building permits may be required which professional installers will usually handle. I was 'lucky' enough to have done some installs in the past while working for a professional installer.

My Experience
I originally bought a cheap point-to-point unit that came with all the stuff to install it in one box, it was simple to set up but had a lot of problems with wind, rain and ice.

I replaced that with a much better point-to-multipoint system that required a little knowledge of what to buy, but the company rep was very helpful in making sure I got all the right parts. That system survived massive ice storms, torrential rains and strong winds in excess of 70 mph without so much as the need for maintenance afterwards, but I made sure to mount them well of course. I finally had to upgrade that with much higher bandwidth setup because we had outgrown the old one.

This last setup cost around $550 per unit, but once set up it hasn't needed any maintenance and I expect it to last many years even under brutal weather conditions.