Report: Mobile Internet use has reached “critical mass”
http://www.ejc.net/media_news/report_mobile_internet_use_has_reached_critical_mass/
http://www.ejc.net/media_news/report_mobile_internet_use_has_reached_critical_mass/
Research conducted at the University of Leicester resulted in the discovery a "time window" when mobile signals and radio waves reach "super strength"-–allowing them to be clearer and travel greater distances, potentially increasing interference with other systems. The research, examining the signal strength of radio waves traveling over the sea, identified late afternoons and early evenings in the spring and summer as the times when enhanced signals are most likely to occur.
Salil Gunashekar, a graduate student in the University of Leicester's engineering department, observes that the research's results could have important implications for the design of cellular phone networks operating in marine and coastal regions. "When radio waves travel for long distances over the sea, their strength can be affected by the weather," says Gunashekar, now a post-doctoral research associate in the department's radio systems research group. "The constantly changing weather conditions over the sea mean that marine and coastal environments, in particular, are prone to unusual atmospheric phenomena that enable radio waves to travel longer distances and have higher strengths than expected."
Meanwhile, in the U.S., researchers at the National Institute of Standards and Technology (NIST) have confirmed that underground tunnels—-generally a difficult setting for radios—-can have a frequency "sweet spot" at which signals may travel several times farther than at other frequencies. The optimal frequency, according to the researchers, depends on the dimensions of the tunnel. For a typical subway-sized tunnel, the sweet spot is found in the frequency range of 400 MHz to 1 GHz. The finding, which uses new data to confirm models developed in the 1970s, may point to future strategies for enhancing communications in road and rail tunnels, subways and mines.
NIST researchers were surprised by how much farther signals at the optimal frequency traveled in above-ground building corridors as well as underground. Tunnels can channel radio signals in the right frequency range because they act like giant waveguides, the pipelike channels that confine and direct microwaves on integrated circuit wafers and in antenna feed systems and optical fibers. The channel shape reduces the losses caused when signals are absorbed or scattered by structural features. The waveguide effect depends on a tunnel's width, height, surface material and roughness, plus the floor's flatness and the signal's frequency.
Lead author Kate Remley notes that the study's results may help engineers design better communications systems for public service and emergency rescue workers as well as those who control search and rescue robots.
http://blogs.wsj.com/biztech/2008/07/18/wi-fi-squatting-a-crime-by-the-victim/
http://www.networkworld.com/news/2008/072108-wimax-at-sea-the-journey.html
http://www.economist.com/business/displaystory.cfm?story_id=11751174
The rapid growth of wireless services over the past few years has created a huge and growing demand for radio spectrum. But with unused spectrum in short supply, researchers are now turning their attention to communications systems that can share frequencies without causing interference to each other. One promising approach is cognitive radio.
Cognitive radio utilizes a network, or wireless node, that can change transmission or reception parameters to avoid interference from licensed or unlicensed users in the same frequency. The concept was developed by Defense Advance Research Products Agency (DARPA) scientist Joseph Mitola as a logical next step for the software defined radios (SDRs) that are emerging today in military and some commercial applications. SDRs use software to replicate filters, mixers, amplifiers and other traditionally hardware-based components to create a radio that can quickly shift between different operating modes, frequencies, protocols and other parameters.
Experts believe that cognitive radio technology may ultimately assist in improving transmission performance over different radio frequencies, particularly for security and military users. Although still an emerging technology, cognitive radio is seen as having great promise in a variety of fields, including public safety and mobile phone communications.
Two wireless networking researchers at the Rochester Institute of Technology have co-authored one of the first textbooks devoted to the study of cognitive radio networks. Cognitive Radio Networks by Fei Hu, an assistant professor of computer engineering at Rochester Institute of Technology, and Yang Xiao, an assistant professor of computer science at the University of Alabama, provides information and applications related to cognitive radio technology for use in research and classroom settings. The book is published by Boca Raton, Fla.-based CRC Press.
Hu and Xiao hope their book will expand the development of cognitive radio applications. "The explosion of wireless communication over the last two decades has led to the need for spectrum-agile communications that are more efficient and less prone to interference from other radio transmissions," Hu says. "This type of technology is particularly important for military and security transmissions where clear, uninterrupted communication is essential."
Cognitive Radio Networks covers a range of topics applicable for future cognitive radios aimed at business, consumer and government users, including research, management and support. The text also examines information theory and multiple access schemes for cognitive radio, as well as spectrum sensing mechanisms and protocol support.
"Cognitive radio is still a nascent technology and researchers and students in the field require data and instruction related to best practices and technology applications," Yang says.
RTG's membership includes independent wireless carriers and wireless carriers affiliated with rural telcos serving or seeking to serve secondary, tertiary and rural markets.
The Spectrum Marketplace, taking place at Denver's Inverness Hotel Sept. 2-4, "is the only event of its kind focused on enhancing company's spectrum position," the two add. "Attendees can expect to receive updates on regulatory issues, open dialogue with all types of spectrum holders, meet interested buyers/sellers, and learn how to leverage spectrum in the wireless marketplace."
According to Monica Peterson, president of Media206, "With the lucrative 700 MHz auction now behind us and most of the licenses held by large national carriers, there is a huge need to create opportunities for the purchase and sale of spectrum in the secondary marketplace. The Spectrum Marketplace offers the forum for license holders to gather and get deals done efficiently and in one place."
Adds Jerry Wilke, RTG's executive director, "RTG has been advocating for spectrum-auction reform since Congress and the FCC first introduced auctions. There are so many innovative entities not only in rural America but all across the country who need access to spectrum. The Spectrum Marketplace will be held semi-annually to allow buyers and sellers to meet and get the word out about available spectrum for sale or purchase, allowing access to spectrum without having to rely on the FCC's auction process which is skewed toward larger companies.
He continues, "With the amount of spectrum currently held by the large carriers, we believe that the Spectrum Marketplace will be a natural forum for these large carriers to divest spectrum to those who want it. Ultimately, the goal of the Spectrum Marketplace is to make available spectrum easily accessible to those who want it."
http://www.reuters.com/article/technologyNews/idUSL1753605220080717
http://www.telegeography.com/cu/article.php?article_id=24137&email=text
With 20 days to go until the opening ceremonies, companies are feverishly putting the final touches on their systems and platforms. The Vice Minister of Industry and Information Technology Xi Guohua said technology will play a crucial role in the Olympics and relevant safeguards have been put in place to protect it and its performance.
He also specifically addressed China’s homegrown 3G communications technology TD-SCDMA, saying it will be ready to take center stage during the Games. Emergency communications systems are also ready for the Games.
Foreign visitors to the Olympic Games won't be able to use their 3G devices, whose technology will not be compatible with China's network. However, Guohua said China Mobile will be happy to lend them 3G phones that use TD-SCDMA technology.