Reader Forum: Hitting the wall – The enterprise’s barriers to LTE

Editor’s Note: Welcome to our weekly Reader Forum section. In an attempt to broaden our interaction with our readers we have created this forum for those with something meaningful to say to the wireless industry. We want to keep this as open as possible, but maintain some editorial control so as to keep it free of commercials or attacks. Please send along submissions for this section to our editors at: dmeyer@rcrwireless.com or tford@rcrwireless.com.
In early 2008, after Verizon Wireless and AT&T Mobility acquired large blocks of the 700 MHz wireless spectrum, it became clear that Mobile WiMAX was going to face a new 4G competitor in the form of Long Term Evolution. While the LTE camp was at least two years behind the deployment pace of WiMAX, the industry could sense a shift in momentum, especially with the majority of global operators lining up behind LTE. Industry observers even labeled the 700 MHz spectrum as “beachfront,” meaning that it could more easily reach mobile subscribers and penetrate into buildings from existing tower locations.
Two years later, expectations are just as high. LTE gives operators the ability to migrate existing assets (spectrum, IP core, cell sites, etc.) towards the next generation of wireless, with potential to deliver LAN-rate mobile data services to subscribers while simultaneously driving down the cost/bit of their infrastructures.
As voice revenues are squeezed even tighter through commoditization, operators have only seen moderate revenue growth despite an explosive growth in data traffic. LTE seems to answer this concern by delivering high-rate data services at a new level of cost-efficiency, capturing new data subscribers and potentially reversing the imbalance between revenue and traffic growth.
While the industry tends to focus on the pace of LTE macro network build-outs, the data growth phenomenon associated with LTE will not be outdoor-specific; LTE coverage indoors is just as important but indoor LTE performance will suffer unless the in-building challenge is included in planning. With this in mind, LTE operators will need to craft coverage strategies to not only attract and retain subscribers, but also to maximize their business case for deploying LTE.
Hitting the wall
Despite the “beachfront” moniker, strong and reliable indoor LTE performance is challenging, independent of whether it is operating at 700 MHz or higher frequencies. Outdoors, 700 MHz signals enable many LTE operators to use existing towers as they build out networks, giving them a deployment advantage over their WiMAX 2.5 GHz competitors. The indoor environment, however, is an equal-opportunity challenge for all 4G players, including LTE operators.
To operate at peak efficiency, LTE requires a high-quality RF environment, often measured by the signal-to-noise ratio. Generally, the SNR is the margin between a service’s signal strength and local noise sources – the higher the SNR, the better the service. With high SNR, the LTE network can effectively “pack” more data bits into each user channel and provide a higher quality of service.
Conversely, in noisy RF environments (a lower SNR), the LTE source must “downshift” to pack fewer bits into the user channel. If the SNR drops dramatically, the LTE source will not be able to support even basic services, resulting in failed or dropped data connections.
In addition to unhappy (and potentially lost) subscribers, operating in these degraded modes can result in situations where the operator needs to consume two to three times more spectrum than would otherwise be necessary, reducing the cost/bit advantages of LTE. Consider this analogous to an airline being forced to fly all of its planes only half-full of passengers, effectively burning money for the carrier.
So what does this have to do with LTE indoors? Everything. Achieving a high SNR indoors is very difficult without a network designed to boost in-building coverage. Radio signals experience severe attenuation when penetrating heavily constructed facilities, significantly lowering the indoor SNR, sometimes to a severe enough level that wireless service is all but nonexistent.
Brick-by-brick
Unlike its 2G/3G predecessors, LTE is initially targeted at high-speed data applications, which are served in many buildings by the incumbent wireless data technology, Wi-Fi. Given that smartphones, tablets and other mobile devices ship with built-in Wi-Fi, some operators were initially reluctant to pursue in-building LTE. When put in perspective with the projected growth of mobile data over the next few years, operators are now seeing the opportunity of indoor LTE.
Not only are carriers looking at massive growth in mobile data traffic in the near future, but also a dramatic change in the nature of that data. Industry projections predict an order of magnitude surge in mobile data traffic over the next three years, exceeding two million terabytes of data per month, with demanding video applications accounting for almost two-thirds of that total by 2013. This evolution is an ideal opportunity for operators, since LTE is tailor-made for high-bandwidth, low-latency mobile data applications. To fully exploit this opportunity, operators are now focusing on the need for high-quality indoor LTE service as it’s the rare user who only wants an application that can be used outside.
It will take some time for LTE to work its way into consumer products, with Verizon Wireless announcing its very first LTE devices at CES just a few short months ago, and for developers to create next-generation applications that capitalize on LTE performance. In the meantime, the early demand driver for LTE will be relatively commonplace – early adopters seeking high-speed Internet access from their laptops. Typically, these subscribers will be technology-savvy business users as they have both the means – they can afford to experiment with an LTE subscription – and the motivation – they’re seeking an indoor alternative to Wi-Fi.
Therefore, operators need to continue to target facilities that have large, transient populations for whom the facility is not “home base,” including:
–Hotels;
–hospitals;
–airports;
–shopping malls;
–government buildings;
–casinos and convention centers;
–universities;
–stadiums.
Certainly, Wi-Fi coverage might also be available in these locations, but these users will prefer a 4G alternative due to real or perceived shortcomings of the local Wi-Fi service, from security risks and battery life to poor performance and cost. Given the choice, this class of user will rely on their LTE subscription – and they will expect a high-quality service.
To build their initial revenue stream, LTE operators should seek out venues with early adopter populations and make certain that they have excellent access to the service. In-building coverage solutions will help operators capture near-term revenue while also satisfying the performance expectations of early subscribers. Moreover, by enhancing coverage in these facilities, operators can ensure efficient utilization of their LTE spectrum and infrastructure, which sets the stage for cost-effective subscriber growth in the future.
In the near term, corporate enterprises with robust Wi-Fi deployments might not have wide-scale demand for LTE coverage. However, it will be a relatively short time before the devices and applications embraced by consumers evolve into business class applications relevant to the enterprise. For instance, Cisco Systems Inc. is already driving mobile video applications with an aggressive push for video conferencing. New classes of mobile enterprise applications will emerge, driving requirements for 4G/LTE coverage inside the enterprise. Ultimately, enterprises will need to rely on both their corporate Wi-Fi network and operator LTE services to accommodate the surge in mobile data traffic.
If you build it, LTE subscribers will
come
In-building LTE coverage solutions are critical to the operator’s success, so beyond providing signal coverage, these systems must also complement the operator’s business case. As such, operators should seek in-building systems that accelerate their time-to-market while remaining cost-effective to deploy. For LTE, this means that the conventional distributed antenna system approaches of the past will not be sufficient.
In the past, some operators addressed in-building coverage issues on a reactive basis, waiting for customer complaints about coverage holes blocking enterprise voice or BlackBerry communications. Operators could select from a wide-range of DAS alternatives (passive coax, active, hybrid fiber-coax, etc.) to address the issue, usually by boosting the indoor coverage. To be cost effective, the approach for LTE will need to be different.
The required solution should be a new paradigm in DAS, a product that supports essential LTE features, such as smart antenna technology incorporating multi-input/multi-output capabilities, but is also packaged in flexible, cost-effective form factors so that operators can get to market quickly. The essential features encompassed by this new paradigm DAS should include:
–Comprehensive LTE MIMO support.
–Even power distribution, to ensure consistent performance throughout a facility.
–Flexible and simplified installation, allowing operators to match enterprise requirements while minimizing installation burden.
–Existing resource utilization, taking advantage of existing fiber and CAT-5e/6 cabling to quickly activate LTE coverage in any facility with an existing LAN or Wi-Fi deployment while transparently coexisting with Ethernet LAN traffic.
LTE will be a vital solution for wireless operators and the enterprises they service. However, there is no magic bullet when it comes to deploying an LTE network, especially within an indoor environment. To fully capitalize on the mobile data boom, operators and their customers must find the right solutions and right integrator that will help them break down the wall between the enterprise and the vast benefits of LTE. The paradigm shifted DAS solution described above would go a long way to breaking down these walls and make the benefits of LTE accessible to all users, anytime, anywhere.