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The growing popularity of smartphones, tablets and other devices is creating a surge in demand for mobile data. According to Cisco Systems, global wireless traffic increased an estimated 160% in the past year alone. However, there is simply not enough network capacity to carry that data. We are already seeing the effects of this, with many users complaining of dropped calls and slow network operation.
The main reason for the problem: there is a limited supply of wireless spectrum – i.e., the radio waves that cellular companies use to transmit voice and data services. Spectrum has been called the economy’s “invisible infrastructure,” and an “interstate system for wireless information.” As that system has become more congested, the government, through the FCC (Federal Communications Commission), has been taking steps to identify new sources of spectrum for wireless use.
Broadly speaking, radio spectrum is divided into two types: licensed and unlicensed. Licensed spectrum includes frequencies that can be reserved for a specific use. These are the ones licensed by the government to cellular companies, as one example. Unlicensed spectrum, also called licence-free spectrum, is publicly owned, and people do not have to apply and pay for a licence to use them.
Finding new sources of licensed wireless spectrum is an involved and lengthy process, often requiring legislative reform that could take years to implement. That is why the FCC has also been encouraging the use of unlicensed spectrum, as a way of easing cellular traffic and extending wireless services.
This is not the first time that unlicensed frequencies have been used in meeting wireless communications needs. The enormous success of Wi-Fi and Bluetooth (and the massive, multibillion-dollar industries they have spawned) are just two examples of successful applications of unlicensed spectrum. There are presently thousands of unlicensed spectrum wireless networks in operation around the world. In the U.S. alone, a number of major cities use unlicensed spectrum for emergency response systems.
What are the benefits of using unlicensed spectrum to deploy communications systems? Chief among them is low cost. Since spectrum licensing fees are not required, overall network costs are much lower. The high price and scarcity of licensed spectrum represent the main barriers to entry for prospective service providers – as well as an impediment to lower communications costs for consumers (since wireless carriers have to recoup those costs somewhere).
Another advantage is rapid deployment. With unlicensed spectrum networks, the need for pre-deployment radio frequency planning is greatly reduced, resulting in unparalleled flexibility in rolling out communications systems. This feature is highly valuable to public safety and emergency response authorities as well as the military, where tactical communications systems absolutely must be agile, mobile, and scalable.
Clearly, unlicensed spectrum has a lot to offer. So much so that FCC Chairman Genachowski, commenting last fall when the agency opened up the TV white space spectrum to commercial use, said, “This new unlicensed spectrum will be a powerful platform for innovation.” At the same time, there are challenges in using unlicensed spectrum to roll out commercial-grade networks. The traditional criticism of unlicensed spectrum has been its susceptibility to interference. This has been the main factor holding back the broader use of free airwaves to roll out wide area cellular networks.
All this has changed thanks to recent advances in wireless communications – in particular, the use of cognitive radio networks, such as xMax from xG Technology. Cognitive radio technology is considered to be the next frontier in wireless communications. Cognitive radios are smart enough to make informed decisions on when and where to transmit, based on past usage and current conditions. They are designed with a high level of built-in intelligence and agility that enable them to adapt their characteristics to the operating environment, thus ensuring optimised transmissions.
xMax employs advanced radio techniques to use frequencies and find available capacity where traditional cellular systems only see static, clearing the way for the deployment of robust, reliable wireless voice and data networks.
Some potential applications for cognitive radio network systems like xMax include rural cellular networks, smart grids and public utilities, public safety, industrial and workforce communications. These are all sectors where the lack of cost-effective licensed spectrum has been a major impediment.
Another example is the military market, where xMax can function as a cost-effective on-base communications system for operations and training support, as well as a tactical cellular solution that can deliver carrier class voice, data and video services on the battlefield. xG Technology is currently collaborating with the US Army on such a project.
As the wireless industry grapples with the challenges of meeting the demand for mobile services, making better use of existing spectrum resources is as crucial as finding new ones. New technologies like cognitive radios will allow unlicensed spectrum solutions to play a vital role in that effort, and help to relieve the spectrum crunch.