Power Junkies
As the number of Smartphones, digital readers, and tablet computers increases, wireless telecom infrastructures must be expanded and upgraded to support thousands of voice, video, and data applications for subscribers. It’s estimated that Apple iPhone users spend 300 percent more time accessing the Internet than typical smart phone users, while requiring 40 times the bandwidth of a traditional cell phone, and 10 times the bandwidth of a BlackBerry®1.
An estimated 80,000 cell sites in the U.S. will require upgrades or expansion in the next 5 years just to keep pace with iPhone subscriber growth. The Motorola Droid bandwidth requirements are driving Ethernet over fiber deployments to 90% of cell sites by 2013. Currently, wireless carriers like AT&T, Sprint, and Verizon are spending billions to upgrade their networks to next-generation 4G LTE to deliver Mobile Internet applications to millions of subscribers.
Macro wireless networks that were designed to support an average user base 5 or 10 years ago can’t support current call volumes or the need for higher-speed data support -- and wireless carriers are hearing the complaints from dissatisfied consumers. Many users have experienced an inability to make or sustain calls in stadiums, on bridges, or even on crowded highways or urban sidewalks simply because the current wireless towers are overloaded. It’s expected that 4G/LTE wireless cells will be much smaller than today’s cell areas, requiring more towers and transmission locations because of the need for better coverage (due to signal attenuation) but also the need for higher per-user bandwidth capacity. Carriers implementing new 4G/LTE architectures will also need even larger backhaul pipes over gigabit optical links, while controlling costs at the same time.
For every network upgrade and every new cell site, these carriers can expect significant increases in telecom energy systems infrastructure and utility electrical demand. Over 1 billion new Smart phones will be delivered globally in the next 2 years and today, nearly one-third of Americans are already using the Mobile Internet. All this new demand needs more advanced power management.
Aligning Business and Energy Efficiency Mandates
To ensure effective rollouts of new services, carriers will need a range of telecom energy systems hardware and power management software options to address the coverage and capacity needs of many different environments. Specifically, many 3G wireless infrastructures are based on 24V DC equipment while new 4G infrastructures are based on 48V DC communications gear. The energy system should allow for 24V/48V conversion and simultaneous support for build-out or incremental expansion of each.
For cost control, carriers will also need solutions that can effectively distribute new 4G services to low-capacity environments while providing options to cover existing services. New 4G solutions should be added incrementally to a network on a build-as-you-go basis, to minimize upfront investment by carriers and shorten the return on investment (ROI). The same principle can be applied to the supporting energy systems infrastructure -- no legacy power plant should be left behind.
While the goal of 4G services is to increase ARPU with new services, carriers must first ensure that existing subscriber services are not disrupted. Early adopters will be willing to pay for new advanced services but carriers must continue to provide service to the majority of subscribers who are not willing to pay and want to purchase only basic services. As a result, new 4G equipment must integrate with the network separately, or it must offer backward support for services previously offered.
There are several energy systems vendors offering hundreds of products claiming to meet the challenges outlined above, but it’s difficult to develop a strategy without a list of business priorities. The key to successful 4G deployment will be to align infrastructure migration with business, energy efficiency, and sustainability needs.
Best Practices for Power Automation and Alternative Sources
The telecom industry is used to addressing priority loads. A best practice for wireless carriers is to invest in modern power plant controller/rectifier capabilities that prioritize sources of sustainable energy before the utility grid or generator sources, while still integrating with existing infrastructure. In other words, at particular cell sites or mobile switching centers where solar, wind, water, or fuel cell sources are available, these sustainable sources of power should be prioritized before drawing on the utility or generator source. The U.S. Department of Energy (DOE) has approved a $2.4 million research and development grant to accelerate technologies that minimize the power loss and heat generation that occurs as electricity moves through the ever-growing service provider network infrastructures.
Service Providers are also being asked to cooperate in SmartGrid automated demand management requests to curb electrical consumption from the local utility during peak demand periods. This is an opportunity for the telecom energy system to intelligently interact with the SmartGrid to deliver the following benefits:
1. Automation of power management by listening and responding to requests from the power utility (protocol-based).
2. Scheduled control, whereby the service provider decides when to go off-grid (calendar-based).
3. Dynamic cost control based on the lowest cost of power during a particular time period from a particular utility (financial-based).
In the future, power management for data centers and mobile switching centers should be communicating and negotiating with the utility SmartGrid. The value proposition of telecom energy systems providers is no longer limited to how efficiently their rectifiers can transform AC to DC, but also how efficiently their controllers and associated software can optimize utility costs by communicating with the SmartGrid as part of a holistic system.
By investing in an end-to-end total efficiency architecture approach, wireless carriers will have the ability to reduce utility and cooling costs while leveraging existing investments to scale their networks at lower relative costs.
Harness, Recapture, and Save
High-efficiency rectifiers with system capacities that range from 10 Amps to 20,000 Amps can help deliver end-to-end power efficiency approaching 97 percent across a wide range of normal load conditions. Typical ROI timeframes enable these total efficiency energy systems to achieve 1-2 year payback periods.
As carriers provision redundant capacity to ensure always-on reliability of the network, there can be an efficiency impact. High-availability DC power plant designs are typically designed to run at 40 percent load which is at the low-end of efficiency for many legacy power plants. Active rectifier management can place rectifiers in standby as part of an overall energy reduction approach to improve efficiency in low load conditions. Active rectifier management is a software-based controller feature that can be enabled on currently installed DC power plants.
Another opportunity to improve reliability occurs during the recovery of an area or region from a large-scale utility power failure. In the event of a complete power failure, power systems are designed to turn their loads back on through controllable disconnects based on voltage and time parameters. A collection of power sites serving a wireless area can be configured locally or remotely to turn the loads on at different times within a wireless region. This alleviates the loading stress and transients on the AC grid in that area, yielding a higher probability of successful power up. Combining this individual site capability with advanced remote management software allows for more intelligent decisions to be made for a much larger area. It also ensures that operations personnel have a complete digital dashboard view across the power infrastructure.
Total Efficiency: The Future Is Now
Controlling energy loss and cooling cost for these new cell sites is more than an idea -- there are already products, services and training available in the market that can help wireless carriers reign in expenses associated with utility and cooling costs, without abandoning existing infrastructure. Every 1 percent improvement in overall telecom energy efficiency delivers $42 million in savings industry-wide in North America.

Figure 1. The drivers and power requirements for changing telecom environments.
Whether expanding existing locations or deploying new ones, total efficiency solutions for mobile internet infrastructures address end-to-end power requirements for Mobile Telephony Switching Offices (MTSO/MSC); outside plant (OSP) cabinets for optical backhaul networks; and cell site equipment huts and shelters. (See Figure 1.) Wireless carriers should seek out energy systems purpose-built to provide the necessary efficiency, reliability and dual-voltage flexibility required as they expand capacity at existing locations and provision new cell sites.
Endnote
1. See the Mobile Internet Report, published December 2009, by Morgan Stanley. Pie charts on page 52 show daily usage breakdown by activity. www.morganstanley.com.
About the Author
Vito Savino is Director of Product Management for Lineage Power. He has more than two decades of experience in telecom power infrastructure design and operations. Lineage Power delivers intelligent power conversion solutions including patented innovation with energy-efficient AC/DC and DC/DC embedded power, indoor/ outdoor energy systems, and custom power solutions. Savino welcomes your thoughts at vito.savino@lineagepower.com. For more information, visit www.lineagepower.com or call 877-LINEAGE.
Verizon’s Powerful Plan
As carriers upgrade their Mobile Internet access speeds from 3G to 4G LTE, it is necessary to also boost power capacity in order to deploy the infrastructure devices that deliver thousands of real-time voice, video, and data applications to millions of mobile device subscribers. Verizon has already begun deployment of Total Efficiency solutions within thousands of outside plant (OSP) locations across the U.S. These solutions support 4G LTE wireless backhaul applications over gigabit optical networks for Mobile Internet infrastructure buildouts, lowering power consumption and cooling requirements by delivering end-to-end energy efficiency approaching 97 percent across a wide range of normal load conditions.
The criteria for Verizon’s OSP selection included pricing, technology, reliability, purpose-built design, service, support, and training. Total Efficiency solutions meet these requirements by delivering high-density power with AC input and DC distribution options purpose-built for Verizon OSP enclosures.
Designed for durability in harsh environments, the battery reserve system selected by Verizon is ideal for OSP power, broadband, access, and other telecom network power applications, helping telecommunications carriers, wireless operators, Internet service providers (ISPs), and large enterprises achieve their sustainability objectives by recapturing up to 70 percent of energy typically lost in the power conversion process.
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