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GCN : February 2013
10 GCN FEBRUARY 2013 • GCN.COM [BrieFing] NEWS ANALYSIS Seattle is jumping on the high-speed Internet train, with plans to install ultra- high speed service for homes and busi- nesses, Mayor Mike McGinn announced recently. The project, sponsored by the Uni- versity of Washington, "is something we've been working on for three years," he said, "so that we can compete in the world economy, so that we can maintain our leadership role in innovation." Broadband developer Gigabit Squared will develop and operate the demonstra- tion ber network in 12 neighborhoods with plans to use wireless to quickly deploy services to other areas in the city. The open architecture network will uti- lize Seattle's excess ber capacity. Giga- bit Squared also plans to lay more than 200 miles of additional ber to create the network, which by the end of 2014, will be available to 100,000 residents. The network is expected to remain in place for at least 10 years. In the demonstration network, more than 50,000 households and businesses in 12 neighborhoods will have access to up to 1 gigabit/sec connections, which the city says is up to 1,000 times faster than the typical high-speed connec- tion. In the second phase of the project, Gigabit Seattle will create wireless ac- cess via radio transmission by placing ber transmitters on top of 38 buildings across the city. The project will not cost taxpayers or the city a dime, McGinn said. Instead, Gigabit Squared will raise capital to pay for the cost of laying the ber and will also pay rent to the city for using its existing "dark" (unused) ber. The project is the rst demonstration project of Gigabit Squared's $200 million Gigabit Neighborhood Gateway Pro- gram, which will promote gigabit network innovation at six universities across the country. The program was developed in partnership with The University Commu- nity Next Generation Innovation Project. • Seattle plans ultra-high speed Internet service NASA communicates with its space probes and exploration vehicles using the Deep Space Network, which relies on low- bandwidth radio waves. It can take up to 15 minutes to send commands as far as Mars, and just as long to get a response back. The answer to faster commu- nication might be lasers, which can carry information optically more easily in space, where there isn't much to block their line of sight. NASA has a satellite orbit- ing the moon called the Lunar Reconnaissance Orbiter (LRO), which is already equipped to accept laser signals though its Lunar Orbiter Laser Altimeter, LOLA, which is mapping the surface of the moon. So NASA figured that in addition to send- ing along the normal tracking data, it could beam regular infor- mation, or even a photo, at the same time. "Because LRO is already set up to receive laser signals through the LOLA instrument, we had a unique opportunity to demonstrate one-way laser communication with a distant satellite," wrote Xiaoli Sun, a LOLA scientist at NASA God- dard in a release following the achievement. For her journey, the Mona Lisa was reduced to 152 by 200 pixels. Each pixel was sent to the LOLA using a laser during the brief win- dow when the tracking and mis- sion data wasn't using the beam. NASA specifically had 4,096 such brief pauses to work with. How much to darken a pixel was determined by delaying the infor- mation pulse. The time di er- ence between when the satellite expected to receive the data and the actual time the data arrived determined how much shading was needed for each pixel. Because of the Earth's atmo- sphere interfering with the laser, the transmission wasn't perfect. However, using the Reed-Solo- mon error correcting code, the same type used to keep CDs and DVDs from skipping, NASA was able to perfectly reassemble the photo on the other end. The Mona Lisa was now orbiting the moon, 240,000 miles away. The transfer rate was equal to about 300 bits per second. While 300 baud modems are far from high-tech these days, the experiment shows that lasers can be used for e ective com- munication, even over very long distances. They are also highly directional, compared to radio waves that radiate out from their source. Theoretically, that could allow for two-way laser commu- nications in the future. "This is the first time anyone has achieved one-way laser communication at planetary distances," said LOLA's principal investigator, David Smith of the Massachusetts Institute of Technology. "In the near future, this type of simple laser com- munication might serve as a backup for the radio communi- cation that satellites use. In the more distant future, it may allow communication at higher data rates than present radio links can provide." --- John Breeden II How NASA made Mona Lisa smile on the moon HOW IT WORKS BY RUTRELL YASIN