Additional spectrum--particularly frequencies in the 5 GHz band--is needed to ensure ongoing possibilities for offloading data from cellular networks, according to a recent study prepared for the European Commission. The study's findings in that respect echo efforts in the United States to free up more 5 GHz spectrum for Wi-Fi use.
The EC-commissioned study, written by J. Scott Marcus and John Burns, recommends efforts be pursued to make spectrum from 5150 MHz to 5925 MHz available globally for Wi-Fi and to make 2.6 GHz and 3.5 GHz "fully available for mobile use." Among other things, the study also calls for consultation on future licensing options for the 3.5 GHz band, which it said could be used for small cells and related backhaul.
The report noted that the 5 GHz band has been lightly used, largely because most Wi-Fi activity is still concentrated in the 2.4 GHz band. "There is little practical evidence at this stage to indicate at what point the 5 GHz band might become congested," said the study, which noted 5 GHz take-up is increasing now that numerous client devices, including smartphones and tablets, have dual-band capability.
The spread of 802.11ac will also encourage use of the 5 GHz band. Further, large-scale public Wi-Fi networks have already become a significant driver of 5 GHz use today, particularly where outdoor coverage is being provided.
The report's authors projected a potential shortfall of between 60 and 180 MHz of necessary bandwith in the 5 GHz band over the long term in Europe based on estimates of future private and public Wi-Fi traffic.
U.S. regulators envision similar issues, which is why early this year the FCC took initial steps to unleash up to 195 megahertz of additional spectrum in the 5 GHz band, potentially opening up the largest block of unlicensed spectrum made available for the expansion of Wi-Fi since 2003.
The EC report also recommended use of the 3.5 GHz band for small cell deployment. The band has been licensed for WiMAX and Broadband Wireless Access (BWA) networks in Europe but has seen only light use.
"The band is also suitable for providing backhaul to small cells or Wi-Fi access points in some locations and in the longer term could be attractive for deployment of new services such as LTE based fixed broadband substitution or delivery of 5G mobile services," said the report.
The United States has similarly moved to open up the 3.5 GHz band for small cell use. In December 2012, the FCC issued a Notice of Proposed Rulemaking (NPRM) that, among other things, would allow small cell devices to deliver wireless broadband service in the 3550-3650 MHz band via a shared-access scheme. The band is currently used for U.S. Navy radar operations and covers 60 percent of the U.S. population.
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