The push towards ubiquitous LTE access has made great strides. Yet for operators, the fact remains that no single technology can necessarily resolve all in-building coverage challenges caused by issues such as construction materials and lines of sight that can often interfere with wireless signals.
The topic of indoor LTE coverage is becoming an even more pressing concern as LTE deployment evolves and mobile usage continues on a growth path to surpass desktops and landlines as the business (and personal) tool of choice. Recent announcements, however, make it clear that the proverbial last mile remains a logistical and financial challenge.
In October, market research consultancy iGR released its U.S. LTE Network Infrastructure Spending Forecast, 2014-2019 that outlines the role of small cells and distributed antenna systems (DAS) in U.S. mobile operators’ LTE investment planning. It stated that with the majority of mobile subscribers using LTE devices, mobile operators are upgrading and “densifying” the cellular architecture with a combination of small cells, metrocells, remote radio heads, and DAS to meet coverage and capacity demands.
This more expansive HetNet (heterogeneous network) approach begs the question, what specific options – or combinations thereof – make the most sense?
Despite best efforts to date, 61 percent of IT decision makers at U.S. firms of more than 250 employees struggle with poor indoor cellular coverage, according to a survey conducted by U.K. research firm YouGov on behalf of SpiderCloud Wireless. On the upside, there are multiple indoor coverage solutions available – including small cells, Wi-Fi calling, and signal boosters – each of which has its own role to play in the HetNet spectrum. (Note: DAS for its part will continue to play a role in large scale venues over 100,000 sq. ft.)
One of the most significant differentiators between these solutions is whether the technology in question requires a broadband or cellular connection. Small cells and Wi-Fi calling, for example, can only be deployed where fixed backhaul with sufficient capacity is available.
Yet Pew Research Center notes that as of 2013, just under one-third of North American households did not have access to broadband services. Signal boosters on the other hand work directly with cellular signals.
As mobile operators continue to enrich the LTE experience for customers, there is no question that they must integrate additional solutions in order to overcome in-building coverage needs at a sustainable cost. A promising aspect of all this is that there are a number of options and combinations that can come into play.
Here’s a brief breakdown of how each of the options can play a role in overcoming indoor coverage issues:
- Small Cells – These are widely used for applications where cell reception is poor or non-existent. Simply put, they are the equivalent of miniature cell towers that generate their own signal (as opposed to amplifying an existing one), so do not rely on macro-level signals to function. As far as implementation goes, small cells require some configuration and registration of devices. While relatively inexpensive, they may incur monthly data charges. As previously noted, small cells require fixed backhaul with sufficient capacity.
- Wi-Fi Calling – This alternative only works with Wi-Fi enabled devices that support a Wi-Fi calling app. In some scenarios, it may have capacity and coverage limitations, and requires considerable configuration. An added factor is that calls may be dropped should a user move from an indoor to outdoor location, since it does not trigger an automatic handover. This service also requires fixed backhaul with sufficient capacity.
- Broad Spectrum (wideband) Boosters – Commonly known as BDAs (bi-directional amplifiers) these analog repeaters amplify wireless signals within a building for one or more operators simultaneously. While often inexpensive and simple to acquire, FCC regulations have required that these devices reduce the gain of residential broadband repeaters to avoid interference with operator spectrum. One important item of note is that many are not approved by the FCC for use, and are often frowned upon by mobile operators because of their risk of interference.
- Smart Signal Boosters – These FCC-approved, digital devices enhance existing mobile network signals, so don’t require a broadband connection. Because they are carrier specific (i.e. specifically designed and built to work on a single operator’s network), they deliver much more gain and capacity than broad spectrum boosters, and provide up to 13,000 sq. ft. of coverage. Since they are self-organizing, multiple units can be deployed throughout an area of a building at a fraction of the cost of running multiple antennas. They can also be combined with indoor DAS systems to extend coverage, making them much more scalable for large-scale applications. In fact the Small Cell Forum’s Release 2: Enterprise guidelines (published in December 2013) was the first to address the synergies between smart signal boosters and small cell networks in the enterprise. More recently the Small Cell Forum published this document, “Alternative enterprise small cell extension solutions,” that provides a number of common small cell deployment scenarios aided with a smart signal booster.
In addition, factors such as existing infrastructure, square footage, budget, scalability, structural interference, ease of deployment, installation expertise (or lack thereof), disaster recovery requirements, and local regulatory requirements will influence the decision to implement one technology over another.
Whatever the outcome, there are ample opportunities for carriers to achieve their LTE goals.
Werner Sievers is CEO of Nextivity, a San Diego-based developer of the Cel-Fi Smart Signal Booster. He is a veteran of the wireless industry and experienced leader of technology-centric, venture backed startups.
Filed Under: Infrastructure