Army's on-the-move connectivity draws closer
WIN-T passes test, driving more interest from developers
- By Terry Costlow
- Jul 25, 2011
The movement to give military forces connectivity to any network node while they’re on the move is advancing rapidly.
The Warfighter Information Network-Tactical (WIN-T) network, which provides continuous network connectivity even as vehicles speed through remote regions, is seeing more interest from developers as it continues to fare well in testing.
As the Defense Department adopts more network-centric operations, WIN-T will provide another method of meeting DOD’s goal of delivering as much information as possible to squads and individual warfighters in the field. The system will pull in signals from many sources, such as satellite communications, line-of-sight and terrestrial signal types.
The latest version of the program, WIN-T Increment 2, is designed to provide high-bandwidth connectivity that can automatically switch between ground-based and satellite connections. When a vehicle is moving rapidly across an area covered only partially by cellular links, it will automatically switch to a satellite connection.
Similarly, when the vehicle enters a city and buildings block line-of-sight signals, it will seamlessly switch to satellite mode. WIN-T Increment 2, which provides such on-the-move capabilities, recently got the go-ahead for continued development.
General Dynamics finished the initial phase of system testing. Pending a successful operational test event and full-rate production decision by the Office of the Secretary of Defense, the Army intends to begin fielding WIN-T Increment 2 systems in fiscal 2013.
“Fieldings will continue until all 54 maneuver brigades and 10 division elements have been fielded" by the end of fiscal 2018, said Pat DeGroodt, deputy program manager for WIN-T Increments 2/3 at the Program Executive Office for Command, Control and Communications-Tactical (PEO-C3T). Its predecessor, WIN-T Increment 1, is fielded to more than half of the Army and will be fully fielded by mid-2012.
Increment 2 is beginning to see more support from developers, who are addressing many technical aspects of the communications scheme. “The ability to do comms on the move in austere environments — that’s taken some significant legs now in terms of development of things like antennas,” said Army Col. William “Chuck” Hoppe, project manager of the WIN-T system at PEO-C3T.
As deployment gets closer, this increased interest from manufacturers raises the likelihood of further performance improvements and cost reductions. One major focus is antenna technologies.
Dishing up progress
Compact Increment 2 antennas are dramatically different from the trailer-mounted, 8-foot-wide Increment 1 satellite antenna. To adapt to constantly changing positions, Increment 2 uses two satellite antennas and one line-of-sight antenna that feature significant advancements in on-the-move technology. The two satellite antennas employ electronically controlled mechanical steering to track satellites while the host platform, such as a military vehicle, is moving.
“One antenna is an 18-inch dish used on the Soldier Network Extension (SNE) node that provides on-the-move satellite access to the network for company commanders,” said Jim Price, vice president of WIN-T/Ground Combat Vehicle at General Dynamics C4 Systems. “The second is a 20-inch dish antenna used on the WIN-T Point of Presence that provides on-the-move satellite access for brigade and battalion commanders and on the Tactical Communications Node that provides on-the-move access for division, brigade and battalion staff.”
The military’s efforts to use a single technology for many platforms will help technicians and users in the field, but it also increases the challenge for those designing antennas. As more wireless systems are deployed, ensuring that they don’t interfere with one another is an equally important factor.
“Co-site interference and frequency management are required to ensure the co-existence of these systems in an overcrowded spectrum, with frequency management being one of the more difficult technical challenges,” said Steven Miller, program manager for electronic solutions at BAE Systems. “Network availability is critical to the success of WIN-T, which translates into the need for high-performing, robust antennas and communications links.”
This interference issue is even more acute because satellite communications is involved. “With small antennas, you’re spraying energy all over the stars,” Hoppe said. “You’re spraying energy potentially on the neighbor satellites, what we call the satellite interference. That runs us into both international treaty issues, violation of international law and a bunch of other things, and frankly it slows other people down with the network.”
While engineers strive to resolve that issue, they must also adhere to the military’s drive to use a single product alongside many different products. Companies that develop antennas that can be used on many vehicles will have an obvious edge over dedicated modules.
“The antennas are designed for multiple ground platforms and airborne UAVs and are well suited for operation in close proximity to other fielded systems,” Miller said. “Affordability of the antennas is key when expanding within and beyond the WIN-T deployments.”
There’s a tight link between antennas and networking schemes. The many variations that occur as vehicles move through myriad conditions and connect to many different sources make this interplay even more important for WIN-T networks.
That means that communication schemes and data transfer rates will constantly change to provide reliable connections at the best possible data rates. Making that work continuously requires a broad system approach that constantly changes.
“One of the critical aspects of WIN-T is the integration of the network into a system,” Price said. “This involves a network management system that was designed hand in hand with the waveforms and antenna.”
One facet of this drive to maintain contact regardless of operating conditions is the ability to change network speeds. When connections via high-bandwidth links are good, bursts of data will transmit as quickly as possible. But when only slower links are available or connections are suspect, transmission rates will be far slower.
“The network adapts its modulation and data rates based upon the link availability and strength provided by its antenna systems,” BAE’s Miller said. “The stronger and more robust the data link, the greater the data that can be passed through by employing sophisticated modulation schemes.”
Those sophisticated schemes account for a wide range of changes, going well beyond simply increasing and decreasing data rates. Continuously changing transmission techniques increase the amount of data that can be sent while letting more users share a network.
“The WIN-T waveforms have advanced features in order to optimize spectrum use,” Price said. “Highly efficient adaptive coding and modulation allow the system to automatically adapt to distance, blockage, fading and weather effects, minimizing wasted power, using only that which is absolutely necessary, thus reducing the spectrum required to operate. In addition, bandwidth on demand allows the system to allocate resources only when traffic requires, providing a significant multiplier in terms of capacity.”
Although the on-the-move capabilities are the focal point of the development, that adaptability has military planners excited. They can potentially use fewer networks and terminals, cutting costs while still bringing more capabilities to warfighters.
“This unique ability to provide just the right amount of spectrum and power resources to each terminal no matter what its size or environmental conditions ensures that each terminal is operating at peak efficiency all the time,” DeGroodt said. “WIN-T also continues to invest in improved coding algorithms to get more bits per hertz from the waveform and the terminals we have available, including our on the move terminals.”
The next step
As the focus for Increment 2 shifts from development to production, the design effort for the next phase is getting more emphasis. Increment 3 enhances airborne communications, providing what’s called an air tier, and it aims to further reduce size and weight while improving connectivity for troops on the ground.
WIN-T Increment 3 will bring enhancements primarily to the line-of-sight waveform, also called the Highband Networking Waveform, and to line-of-sight antenna systems. That will help extend the reach of transmissions so there’s less reliance on satellites.
“In the LOS area, Increment 3 introduces the JC4ISR radio running an improved version of the HNW waveform, coupled with the a new, narrower beam antenna design will provide a two to four times improvement in spectrum reuse over what the Increment 2 LOS directional antenna is capable of delivering today, “ DeGroodt said. “This increase in efficiency will result in significant improvement in throughput and allow more network members to be supported at greater ranges than the current WINT-T Increment 2 LOS radio and antenna.
Introducing an air tier will increase throughput, decrease latency, and decrease reliance on scarce and expensive satellite resources. Adding the air tier has required the integration of two separate LOS bands, one for ground-to-ground communications and a second band for ground-to-air communications.
“Good progress is being realized and prototype antennas are already in early test phases,” DeGroodt said. “The Army intends to fit these advanced WIN-T Increment 3 antennas and radios into the final Increment 2 fieldings to realize the significant increase in performance and to ensure WIN-T Increment 2 elements are ready to accept the Air Tier as soon as it is ready for deployment as part of WIN-T Increment 3.”
Suppliers are already preparing to help make sure that this transition occurs smoothly.
“WIN-T Increment 3 antennas are a critical component to providing terrestrial and aerial network layers,” Miller said. “Once deployed, it is expected that WIN-T Increment 3 will replace the current Increment 2 network of products delivering full, high bandwidth, and secure networking to the on-the-move warfighter."