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Zoom me to the White Spaces
The future is right now. Clear signal, completely unimpeded wireless audio and video service is available to public safety and IT professionals. All because two companies, Lake Mary, Fla.-based Spectrum Bridge Inc., (SBI) and TV Band Service, LLC (TVBS) in Wilmington, N.C., partnered up recently to develop a great untapped resource in wireless spectrum called TV White Spaces.
This “beta-testing” is being tried out for the first time in an area of North Carolina that is quite used to “firsts.” Leslie Stanfield, information technology director, New Hanover County (N.C.) IT, explained how Wilmington/New Hanover County became the first to get TV White Spaces, also known as WS for short.
“New Hanover County was the first community in the nation to make the switch to digital television and therefore a great starting place to have WS available for something other than television transmission. The spotlight on our community from this effort drew the attention of companies wanting to begin early testing of WS for data transmission.”
The equipment used for WS was called “cognitive radio,” she noted, in that the radios communicate with a database to determine available spectrum to use. “We have a number of ‘hub’ radios and a number of ‘spokes’,” Stanfield said. “Each project area, such as Hugh McRae Park, Creekwood Housing Community and Page’s Creek, has one hub radio. There can be more than one spoke on each hub as is the case at the park where we have a video surveillance camera and a public Internet access point. We are getting about 1.5-mile distances from the spokes to the hubs, which is much better than traditional wireless technologies that have been available to us.”
New Hanover County houses approximately 195,000 residents in 198 square miles, making it the second most densely populated county in North Carolina.
One of the uses for the WS system allows streaming live video to help monitor events in the community. “We have a video camera in Hugh McRae Park and a traffic camera on the Martin Luther King, Jr. Parkway,” Stanfield noted. “Since we are still in the prototype/testing phase of the project, neither are monitored full time. We are just starting to talk about the possibilities of using this technology in a very practical sense. The streams can be viewed on the MDTs we have in the squad cars. We see it becoming an integral part of our monitoring and surveillance programs.”
A number of other potential uses of the technology exist. “We see it as a way to extend our wired network to places we have not been able to go before,” she said. “Because this spectrum is able to travel longer distances and seems to be better at penetrating into dense vegetation than other spectrum we have used, we are looking at monitoring technologies, public wireless, traffic control and others.”
So where did this technology come from? The experimental network currently in place in Wilmington/New Hanover County, deployed by SBI and TVBS, uses the vacant VHF and UHF frequencies left over from the digital transition from analog TV back in June 2009. The FCC has designated several incumbent TV band users, including public safety, priority over the new unlicensed TV White Spaces devices.
But how exactly will it help public safety and IT? “This network essentially provides the community with a transportation traffic camera for real-time traffic monitoring to reduce congestion and enhance public safety,” said Philip Hill, Communications Engineer at Spectrum Bridge. “It provides Wi-Fi access at a community park, and in an under-privileged community, it adds the virtual presence of video monitoring into a park. Also, it provides access to remote wetlands helping to eliminate the costs associated with physically driving and boating to remote locations to collect data required by the environmental protection agency (EPA).”
According to Hill, TV White Spaces have several important properties that make them highly desirable for wireless broadband communications, including the following: Propagation: Due to their relatively low frequencies (54MHz to 698MHz vs. 2400MHz for Wi-Fi), WS has much better propagation characteristics than most other unlicensed bands. This is a matter of simple physics. At lower frequencies, signals generally go further and provide coverage over greater areas for the same amount of transmit power. Penetration: WS frequencies have good building and foliage penetration characteristics. Non-Line of Sight: These frequencies are able to bend around obstacles to a much greater degree than the higher frequencies used by Wi-Fi (i.e., 2.4 GHz). Broadband: Each WS channel is six MHz wide. Multiple channels may be linked together to create higher bandwidth channels. “These are among some of the primary capabilities that make WS highly sought after for wireless communications,” Hill noted, “and commonly referred to as ‘beachfront frequencies.’”
Hill indicated the FCC has issued a set of rules that define what devices may be used in WS. The devices that operate under these rules are called TV Band Devices or TVBDs. They are defined two ways. One is Fixed TVBD, which defines devices that are stationary (fixed in place), and not allowed to move or be mobile during operation. They operate on TV channels 2-51, excluding channels 3, 4 and 37. The second is called Personal/Portable TVBD, which includes devices that are allowed to be mobile and can operate on TV channels 21-51, excluding channel 37.
According to Hill, the United States is undergoing a fundamental transformation driven by broadband connectivity. However, there are unserved and underserved areas of the country, particularly in rural communities with limited or no broadband communications options. The current presidential administration has allocated $4.7 billion to broadband stimulus programs that seek to address this shortcoming. TV White Spaces could provide a cost-effective and rapidly deployable solution to bring wireless broadband to these communities.
Hill continued: “Wireless carriers are also experiencing an exponential increase in traffic volume, especially in urban areas due to the proliferation of Smart Phones. Wi-Fi technology has helped to alleviate some of this congestion through widespread availability and low cost. However, as demand for bandwidth continues to grow, White Spaces technologies can provide the means for offloading traffic from traditional networks.”
One area of interest for public safety is in the setup of something called a Smart City Network. “(It’s) a comprehensive term for giving a city government and citizens the digital tools to measure, monitor, and alter the way they use valuable resources and services,” Hill stated.
“This will expand the country’s Smart Grid, which has received $3.4 billion in stimulus funding from the U.S. government. WS can be a valuable contributor to the wireless ecosystem supporting these applications.”
SBI provides a simple Web-based interface that lets anyone view the availability of WS for a location they input (see www.showmywhitespace.com). The company also provides a free application for locating available WS channels wherever you are—directly from your smart phone. The ShowMyWhiteSpace application is available for download on iPhone/iPod touch or Android-based phones.
How it Works
What about this hub-and-spoke radio deal? “The hub radio is physically connected to the Internet through an Ethernet connection,” Hill explained. “This connectivity is required because the radio must communicate with the Spectrum Bridge WS database to provide the geographic location where it is installed in the form of a latitude and longitude coordinate.
“Once this registration information is received from the radio, the database then returns a channel map to the device of the currently available WS channels. Using this channel map, the hub radio tunes to one of the ‘available’ channels and begins operation. The spoke radios operate in much the same way as the hub radio, except that it must first scan the channel bands looking for a hub radio to ‘join’ with before it can access the white spaces database, via the hub radio, to receive a valid channel map from the database,” Hill said.
In terms of installing the White Spaces system, Hill said it all depends on the situation: “Since these networks are experimental, we began each installation with a site survey trip to become familiar with the area. As our knowledge in WS grew, we have been able to eliminate the need for a site survey trip. During the installation process we partnered with local officials and some major players who helped us physically go out to the site to get the networks deployed. This served to prove there was no interference being created by the installation of the White Spaces networks.”
Hill indicated the company is not currently accepting any applications for the remainder of 2010 but, “we now offer an Experimental White Spaces Network Deployment Kit. This kit is simple to set up right out of the box and it has detailed instructions for users such as service providers, equipment providers, solutions providers and system integrators. The basic kit has a hub radio and four spoke radios with options such as the band; VHF or UHF, antennas and outdoor enclosures. In order to use the kit, each operator must apply to the FCC to request an Experimental White Spaces license for a specific geographical area.”
TV Band Service
William Seiz, Senior VP at partner company TVBS, explained White Spaces TV: “White Spaces is a generic term that refers to the unused spectrum channels in the TV band. The system is really a form of wireless communications, just like cell phones, Wi-Fi or over-the-air television. WS refers to the location in the electromagnetic spectrum where communication devices operate, which is the TV band. Wi-Fi and cellular devices operate in a different part of the electromagnetic spectrum.”
Seiz indicated that TVBS and SBI each brought particular abilities to WS communications networks. “SBI is a database administrator. Their database “talks” to a radio operating in the WS to tell it which channels are occupied by incumbent users, and which channels are unused (WS) and therefore safe to communicate on,” he explained. “TVBS constructs and manages WS networks using radios for communication services. These radios talk to the SBI database in order to operate without interference to other users of the TV band. TVBS also develops and tests specific applications at its Wilmington, N.C., testbed. SBI is expert at radio technology and works with TVBS in developing and testing radios and applications. SBI also supports networks in other parts of the United States.”
White Spaces seems to be a bigger deal for rural areas, as opposed to urban areas. Seiz said, “The amount of benefits will probably be a function of the amount of WS available in a specific geographic area. But where there are unserved rural areas, WS will definitely help in providing broadband.” More populated areas may have a challenge to serve broadband to those who can’t afford it, and the WS may help here, Seiz related. The WS will definitely help in providing needed data communications for certain service applications in both areas.
An FCC ruling later this year should help clarify the rules to this space-age game. But it seems as though the feds are moving cautiously. Seiz commented: “Back in November 2008, the FCC unanimously voted to authorize the unlicensed use of the WS for communications benefits. Once the rules were made, various entities petitioned the FCC to reconsider and vacate the rules. Other entities also sued in the 12th Appellate court to have the rules vacated.” He said the FCC will, hopefully, ratify the original (or close to it) November 2008 rules allowing unlicensed use of the WS under conditions of FCC radio certification.
“When, hopefully, the WS rules are ratified and it is legal to operate in the WS TVBS,” Seiz added, “with the participation of SBI, we hope to construct and manage other networks based on all that we have learned and are learning from the original model of Wilmington. Simultaneously, we will still be participating in developing new WS technology and applications at the Wilmington testbed to better improve future and existing WS networks.”
So what is the law enforcement/public safety/IT take on this? Stanfield said, “Once the technology is ready for large-scale deployment, law enforcement sees it as a way to more effectively monitor trouble spots around the county. We have tried traditional mesh technologies and have seen limitations in some areas, and it has proven to be more costly than what we can deploy. The use of White Spaces should fill a nice niche for us.”
WS can be a problem-solver by extending free Internet access into areas of the community that aren’t being served enough. Stanfield continued, “It allows IT to be more responsive to our users who might need such diverse services as water quality monitoring, video surveillance or remote equipment operation.”
Like everyone else, her community is awaiting final regulations from the FCC on how they will be able to use this spectrum. “If it remains unlicensed and available for us to use,” she said, “we will quickly move forward with deployments. It will never replace the licensed spectrum public safety has come to rely on for their daily communication needs, but it adds another tool we can use to extend the reach of our law enforcement personnel.”
Using radios connected to the Internet to form a wireless system to protect the community served by public safety is what WS is all about. Bending a clear signal through Whites Spaces that helps better protect our citizens and keeps them safe is pretty cool stuff.
Timothy R. Burke is a writer, editor, designer and photographer. He can be reached at firstname.lastname@example.org.
Photos courtesy of Spectrum Bridge.
Published in Public Safety IT, Jul/Aug 2010
Rating : 9.3
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