These conditions are among the reasons that ABI Research anticipates that in-building wireless deployments will increase at a compound annual growth rate (CAGR) of nearly 20 percent over the next five years. Worldwide revenues for in-building wireless systems were more than $1.3 billion in 2006 and will likely grow to $3.6 billion in 2011, according to the researcher.
There are several technological approaches to bringing the outdoor cellular network inside. There are also funding, regulatory and administrative issues to work out with mobile network operators, who own the licensed spectrum that transports the cellular traffic. The rest of this article will explore the ins and outs of these issues.
Approaches To Indoor Mobility
In-building systems extend cellular voice coverage, data coverage or both indoors. At this juncture, it is common to use WiFi for indoor data applications, given that WiFi bandwidth, once installed, is “free,” with no usage charges. WiFi is widely available and most laptops ship with a WiFi card for connections. However, users in locations without WiFi infrastructure might rely on cellular data network connections to access the Internet and internal data resources.
Currently, though, most enterprises looking at in-building cellular systems are attempting to accommodate internal mobile voice requirements. Of those that prefer cellular technology to Wi-Fi (Figure 1), many are very large and have enough revenue clout with the mobile carrier that the carrier will actually build and manage the system at no cost to the enterprise. For some such large organizations, this is preferable to footing the bill in-house to build out WiFi densely enough for full voice coverage and contending with inter-access point handoff issues that still pose performance and reliability challenges for large-scale Vo-Fi.
