Cognitive Radio

Key Bridge implemented a study for the US Military to investigate the feasibility of combining existing wireless protocols and standards with best-of-breed RF networking technologies, plus a standards-compliant IP routing architecture.

Mobile Ad-Hoc Network (MANET) Radio Waveforms

Ubiquitous connectivity is often incompatible with high throughputs, and maintaining quality of service (QOS) often requires stable network topologies.

Mobile ad-hoc network characteristics often vary, from stable to rapid dynamic change, and from just a few nodes with good signal strengths to large, widely dispersed nodes of varying types and capabilities requiring different speeds and feeds.

A key challenge for the long-term viability of Mobile Ad-hoc Network (MANET) systems will be finding and incorporating technologies that enable the network to dynamically adjust itself to conditions as they change over time. Such cognitive radio capability will ultimately enable applications to direct the network to preserve and prioritize certain capabilities over others, for example temporarily sacrificing widespread connectivity for high speed throughput, or instead configuring for low-speed, ubiquitous connectivity.

While the US Military has led the development and adoption of tactical ad-hoc networking, the applicability and utility of this technology is potentially far reaching. Almost any form of peer-to-peer inter-device communication scenario lends itself to a derivative application of Military-inspired ad-hoc networking technologies.

As examples, we considered existing wireless consumer electronic networking applications that might directly benefit from the Government’s research, typified by Microsoft’s Zune peer-to-peer music sharing capability and Apple iPhone’s “Where” application (a civilian analogue of blue-force tracking for friends). Another more challenging but equally promising future example is inter-automobile sensor networking, whereby neighboring automobiles are aware of the speed, distance and actions of their neighbors.

We identified a set of radio waveform standards capable of incorporation into a small number of low cost, low power, high-bandwidth, wireless connectivity devices to demonstrate high-quality, low-latency ad-hoc connectivity between two or more nodes. We concluded that aspects of an Orthogonal Frequency Division Multiple Access (OFDMA) based solution would provide several advantages for the evaluation of off-the-shelf IEEE 802.16(e) compliant technology.

We then evaluated the software footprint of the selected waveforms to determine the required processing power to implement our proposed solution in a software-defined radio.