Friday, October 22, 2010

JTRS effect on military communication

At present, many soldiers don’t have communications radios because the hardware is too expensive. Buying 2-way radios from Radio Shack before deployments solved that problem for some soldiers, but insecure communications created others. On the high end, the US military’s JTRS program is expected to create radios that are much better at working together, and much easier to upgrade. As one might expect, however, the hardware appears to be on track to be more expensive, in return for that improved performance.

The US Defense Advanced Research Projects Agency’s Wireless Network after Next (WNaN) program aims to shift the approach used to design these military wireless networks. It also intends to use inexpensive, high-volume, commercial off the shelf hardware components. They would be combined with adaptive wireless network software operating over densely-deployed, low-cost wireless nodes, with the aim of putting a reliable communications radio into the hands of every soldier.

Right now, military wireless networks are designed for radio range. Instead, DARPA wants to employ more of an ad-hoc swarm strategy, and design for node density. The idea is that with more WNaN components on the ground, it becomes easier to find other nodes in range and link to them, creating reliable local networks.

Those ad-hoc meshes could then be combined with more expensive gear that connects the whole network back to HQ. The result? Everyone has an inexpensive radio, and the group still has full radio range and performance.

WNaN has 2 complementary components. When integrated together and deployed, DARPA hopes that these 2 components will create a distributed, intelligent network entity that is more than the sum of its parts.

The first focus area (WANN) is low-cost, multi-channel, spectrum-agile, MIMO-capable wireless nodes, built with inexpensive RF circuit technology. MIMO technology can already be found in some homes these days, where advanced wireless Internet routers use multiple antennas at both the transmitter and receiver for better performance.

The second focus area (WAND) is a network with densely deployed low-cost wireless nodes, and adaptive network layers that mitigate the shortcomings of any individual nodes by leveraging their rich interconnection. A philosophy that’s very much like the Internet itself.

Raytheon BBN identifies several key aspects of their WNaN efforts:

Dynamic Spectrum Access (DSA). eliminates frequency pre-planning and fixed frequency assignments, in favor of DSA techniques that sense which spectrum is in use and which is available. It’s backed by strict policy compliance checking, in order to use the right spectrum at the right time.

Multiple Transceivers. WNaN’s MAC and network protocols are designed from the beginning to operate efficiently over 1, 2, 4, 6, or even more channels. Complements DSA.

Disruption Tolerant Networking. Today’s networking protocols all drop packets immediately if any node along the path loses the route to the destination. In WNaN, the nodes store packets temporarily during link outages. In field experiments, this DTN implementation sitting under the standard IP stack has delivered 100% of the traffic in situations where traditional IP-networking delivered less than 10%. Because DTN sits under the standard stack, all current IP applications still work.

Content Based Access. Instead of having to know the exact filename, transport protocol, and node, CBA techniques that allow users to query the network to find information, and some critical, often used data like maps can be automatically pre-placed around the network.

Multicast Voice with Quality of Service. Configurable call groups that can support the kind of quality and reserved network capacity required for voice communications, or ensure that high-priority data makes it through demands on the network.

Energy saving portability. The WNaN protocols are designed for small handheld devices, and targeted for embedded operating systems and processors. They include energy conserving capabilities.

You can learn more about the history of this program here.

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