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 we maintain some editorial control to keep it free of commercials or attacks. Please send along submissions for this section to our editors at: dmeyer@rcrwireless.com.
Operators are desperate for spectrum that will facilitate LTE migration. By 2020, Morgan Stanley predicts, there will be more than 10 billion connected devices globally. Consumers increasingly expect access to data anywhere and on any device, placing increasing pressure on mobile networks. LTE offers operators the chance to relieve some of this pressure and deliver data at a low cost per bit and low latency.
The spectrum “crunch” crossroads
Spectrum that will enable LTE migration has been made available in a handful of countries around the world – including the United States. The vast majority of other countries continue to wait for respective regulators to hold auctions. The demands of increasingly bandwidth-hungry mobile users will prompt operators to bid aggressively for new spectrum when these various auctions take place. The timing of these auctions remains entirely out of the operators’ hands.
However, the delays in auctions taking place are unlikely to appease the new breed of impatient mobile data users. Human nature means that the operators will be made accountable for poorly performing networks irrespective of whether regulators make new spectrum available. Operators are therefore wise to the fact that existing spectrum currently being used to deliver 2G and 3G services can be reused to support new LTE services. So-called spectrum refarming has considerable cost advantages compared to the cost of buying new spectrum. Retendered, refarmed spectrum could also sustain LTE services throughout the short term until additional spectrum is made available. Operators must ensure, however, that the spectrum refarming process is carefully planned to avoid service degradation for existing 2G and 3G mobile users.
Reusing existing spectrum
While certain frequency bands are seen as a traditional home for certain technologies, it’s possible to take spectrum currently in use for 2G and 3G technologies and reuse it for LTE. The 2.6 GHz band might be earmarked for LTE deployment, but there’s nothing preventing operators from deploying the technology in other bands. Refarming spectrum does, however, rely on regulators retendering spectrum, once the original license periods have ended, back to the operators under new terms. Despite this, the amounts of money paid for refarmed spectrum pales into insignificance compared with the sums being paid for new LTE licenses.
A recent study by Aircom International recently compared the prices paid by winning bidders at recent spectrum auctions in Europe and North America against the cost of refarming spectrum. The research found that the cost of reallocating a 5-megahertz chunk of spectrum (the amount commonly refarmed) is a mere 0.5% of the cost of acquiring the equivalent amount of new spectrum over a 20-year period. Furthermore, the same amount of refarmed spectrum could sustain LTE services for up to three years and reduce the requirement of additional spectrum by a third. Any savings gleaned could then be reinvested into the network to sustain quality LTE service delivery – a luxury that was not afforded to new 3G services.
Although spectrum refarming is a no-brainer for mobile operators, reallocation of 3G and 2G spectrum is not without its risks. Legacy technologies will be around for quite some time, and the remaining allocated spectrum needs to be carefully managed to make sure quality of service is maintained for existing users.
Spectrum refarming is tried and tested and has become commonplace. In 2000, when U.S. carriers began migrating from TDMA to GSM, it was necessary for operators to reuse existing spectrum. Mobile has always needed to support legacy technologies alongside the new – GSM, UMTS, CDMA, W-CDMA, HSPA, HSPA+, LTE and eventually LTE-Advanced. As the ecosystem of devices becomes ever more complex, operators will need to use single-frequency bands for a variety of different technologies.
Technology-agnostic licenses: the holy grail
While refarming has the ability to dramatically enhance spectrum efficiency and allow operators to maximize what they have, it does call into question whether so-called technology-agnostic licenses might be the most effective way to drive further efficiencies. Regulators remain wary of such practices, as technology-agnostic licenses could reduce the amount of money raised at auction for technology-specific spectrum. This should be weighed up against the potential benefits that greater digital inclusion could deliver to a national economy through stronger and faster mobile broadband throughput.
Spectrum efficiency must always be the goal of network operators and regulators alike. But this needs to be tempered against the quality of mobile broadband service being delivered to mobile users today. The delivery of this improved connectivity is dependent on there being a sufficient number of devices available to economically legitimize and support LTE services using existing 2G and 3G spectrum. Despite this complexity, refarming creates an effective bridge between maximizing spectrum efficiency and accelerating LTE service availability. Operators must do everything they can to ensure that existing 2G and 3G users don’t get a raw deal and become victims of LTE’s progress.
