In part one of this series we talked about investing in an in-building wireless solution for mobile telephony. Assuming that your company is already planning on an upgrade to the campus wireless LAN, now is a good time to start planning for an in-building solution for GSM (or CDMA) and 3G mobile data. This last piece is important to consider because some people just get into the habit of using their 3G card, and there's no reason to stop them if it works.
There are several key benefits to improving mobile telephone signal on campus. The first is an opportunity to make the mobile telephone the only telephone for many workers, simplifying things to one telephone, one number and integration with corporate PBX, voicemail and call routing features. Second is increased performance for cellular and for device battery life. When the signal is poor, it consumes more power, draining the battery more quickly. When the signal is strong, workers can use their mobile telephones wherever they are, further reinforcing the behavior.
Any in-building wireless investment has several "best practices" around design objectives, budgeting, architecture and planning. We discuss these below.
As with any project, there should be a set of design objectives for an in-building wireless system. One objective may be signal improvement indoors, and another may be outdoor signal improvement. These objectives are not necessarily exclusive, but they will factor into the overall plan and budget. Plans to incorporate 3G and 4G mobile data should also be a factor, because they will influence architecture choices.
Other factors include sensitive areas where RF radiation can cause problems with delicate equipment. In these areas, signal improvement can actually lower the levels of RF. Other areas, such as conference rooms and auditoriums, may be places where IT may want to block the cellular signal or cellular voice frequencies while enabling 3G mobile data. Also, there should be a plan for guest worker access to services like Wi-Fi; if there is no guest Wi-Fi access, 3G network improvement should be especially important.
Who should pay?
The most important design objective involves budgeting -- specifically, who should pay. Many in-building wireless solutions have taken a fair amount of time to reach the market because enterprise telecoms departments have been waiting for wireless operators to pay for on-campus signal improvement. As a best practice, enterprises should pay for in-building wireless infrastructure. There are two reasons for this. First, the IT department will have greater control over the project, its objectives and its timing. The second reason is vendor management – when the enterprise owns the in-building infrastructure, IT management is in a significantly better position to enforce contracts and negotiate pricing and other terms.
Passive versus active
There are two types of in-building wireless systems. Passive systems distribute the RF signal from the mobile telephone network around a campus using coaxial cable and bi-directional amplifiers. In comparison, active systems have the ability to distribute the signal around the campus as needed and can use leased lines to connect directly to the carrier wireless network.
Even though we're talking about in-building wireless, a key component of the infrastructure is cabling. Active systems can also support a wider variety of cabling, such as category 5, fiber and others. The cost of cabling and the design requirements of different cabling types are key factors in the total cost of an in-building solution, so don't be surprised if prices vary considerably from one solution to another.
The final comparison point on passive versus active in-building wireless is data capabilities. A head-to-head comparison of the two types of systems for 2G voice applications may point toward a passive system -- in Europe, passive systems do a fine job of supporting GSM traffic. However, if 3G is in the cards, an active system is the best way to keep data rates at full performance.
The RFP process
With a clear set of objectives in mind, IT departments should talk to as many vendors as possible. Pricing varies significantly depending on the application, and cabling may prove to be a major expense. Managers making investments in cabling might want to consider a system that can handle both Wi-Fi and cellular telephony on a shared infrastructure. Many active systems use LAN-like architectures that can scale effectively while supporting both voice and data applications at different frequencies.
With proposals in hand, IT managers will find that in-building solutions are often apples-to-oranges comparisons. For a number of reasons -- including technology, architecture, capabilities and installation cost -- prices will vary from one vendor to another. This is common because there is no single way to optimize in-building wireless performance. But get your plans together and budget accordingly, and your users will call you in the office on their mobile phones to thank you.