Sarnoff, Air Force demonstrate wireless technology at JWID
- By Bob Brewin
- Sep 08, 1996
David Sarnoff Laboratories has adapted an emerging commercial wireless technology to transmit wideband data - potentially up to 2 gigabit/sec - to battlefield communications.The technology called Local Multi-Point Distribution Service (LMDS) originally was developed to transmit more than 100 channels of TV into the home. But at last month's Joint Warrior Interoperability Demonstration at Shaw Air Force Base S.C. the Air Force and Sarnoff demonstrated LMDS' ability to solve the "last-mile problem" for broad-band battlefield communications.
Bill Paglione a senior member of the Sarnoff technical staff said the adaptation of LMDS to military use showcased during JWID "definitely demonstrates we can solve the last-mile problem.... Since this contract called for us to use [the] legacy system we were sending data at the maximum speed of [N.E.T.] IDNX routers which is 8.44 megabit/sec from a hub to four receive sites."
Paglione said the system could transmit up to 2 gigabit/sec of data "if someone developed a modem that could do it."
Sarnoff took existing LMDS technology and adapted it to fit the Air Force's requirements Paglione said. This included configuring the transmitter to operate in the military band 25.25 GHz to 27.5 GHz rather than the commercial band which operates above 27.5 GHz.
Because LMDS was developed to transmit TV signals one way Sarnoff also configured the Air Force system so remote sites could operate on a two-way basis. Sarnoff also tweaked the commercial LMDS gear so it could handle digital rather than analog signals.
Logimetrics for example provided the gallium wave amplifiers while Fairchild provided the modem Paglione said.
Lt. Col. Mike McCullough chief of the engineering and technology validation office of the Air Force Communications Agency Barksdale Air Force Base La. said Sarnoff managed to convert the commercial LMDS technology to military requirements in record time. "We started on this eight months ago with a concept paper we gave [Sarnoff] the money six months ago and we took delivery six weeks [before the start of JWID]."
The Air Force used the Sarnoff system as the backbone local-area network during JWID easily hooking together the Network Operations Center the Air Operations Center and the Wing Operations Center. The system provided full Non-classified Internet Protocol Router Network connectivity McCullough said as well as "two megs for video and two megs for voice."
McCullough believes that adaptation of LMDS technology can solve the broad-band distribution requirements of deployed U.S. forces such as those in Bosnia. For example NATO and U.S. headquarters in Sarajevo are miles from the satellite site that carries wideband data - including live video from Predator Unmanned Aerial Vehicles - into the theater.
Troops in Sarajevo installed a military point-to-point microwave system to connect the headquarters to the satellite station but this system lacks the flexibility of the LMDS system which is omnidirectional McCullough said. The frequency range used in the JWID demonstration is also available to the U.S. military worldwide - another important consideration.
LMDS technology additionally offers the ability to serve users located far from the transmitter hub according to Paglione. "We can go anywhere in a 25-mile radius " he said. That assumes clear terrain and the lack of rain because signals in such a high-frequency band are subject to rain fade Paglione said. "We can do about three to five miles in a heavy rain " he said.
The Army has decided to evaluate the potential for using LMDS in its future Warfighter Information Network battlefield architecture according to Army Lt. Col. Dean Ptaszynski the operations director for JWID.
Ptaszynski said Lt. Gen. Otto Guenther the Army's director of information systems for command control communications and computers saw the Air Force LMDS demonstration during JWID and wants the Army to evaluate its potential. Paglione said the "Army was very interested. We've already had inquires on what it would take to make this equipment ready for deployment to Bosnia or Saudi Arabia."
McCullough said that besides delivering wide bandwidth on the battlefield LMDS-type technology also could emerge as a truly low-cost solution putting the cost of the omnidirectional hub at about $190 000 and the remote sites at $15 000. That depends upon the Defense Department benefitting from economies of scale that would come from widespread commercial use of LMDS technology Paglione said. According to an article in last Monday's Washington Post that day may soon come. The Federal Communications Commission according to the Post soon will auction LMDS frequencies in 493 markets nationwide with a number of companies planning to cash in on the new market.
David Mallof president of Washington-based WebCel Communications which plans to bid on LMDS licenses called battlefield distribution of wideband data a "logical use of LMDS technology."