DARPA Wants to Create Jam-resistant Comm System With 10 GHz Bandwidth

DARPA is soliciting for innovative research proposals to explore the feasibility of a wideband spread-spectrum RF communications system with greater than 10 GHz of instantaneous bandwidth in its Hyper-wideband Enabled RF Messaging (HERMES) effort. The communications system has to operate below 20 GHz to mitigate atmospheric absorption and must employ coding gain and spectral filtering for resistance to jamming.

Proposed studies will advance technology through “1) investigation of system architectures, channel propagation effects, spectrum regulation, signal processing techniques and culminating in a demonstration using commercial components and 2) the development of novel receiver technologies with a path towards a hand-held radio size, weight and power envelope.”

The document DARPA-BAA-14-34_HERMES_Final_For_Posting_30June2014.pdf has more details on the opportunity. Explaining the need for the research, DARPA states, “Allocating small slices of the spectrum to defense allows adversaries to effectively target their efforts. As a result, we have seen the aggressive development and fielding of electronic attack technologies. The effort described herein will study means to reclaim this lost bandwidth without unintentionally jamming others.”

Here is the document's technical description of the HERMES effort:

“In recognition of these severe and mounting challenges, DARPA is exploring extremely wideband RF links. Increasing bandwidth provides resiliency to interference through two principle modes. First and foremost, interference can be mitigated through coding gain using techniques such as direct sequence spread spectrum. Wideband operation has the potential to provide a significant coding gain while also providing operationally useful data-rates. To date, coding gains of more than 50 dB have been demonstrated but with data-rates below 100 bps. Increasing the bandwidth by a factor 1,000 will yield a commensurate increase in data-rate while maintaining the coding gain. Second, operating at over 10 GHz of spectrum with large fractional bandwidth also provides resistance to jamming through a less conventional means. The fundamental physics of high-power amplifiers tends to stifle attempts at delivering high power jamming signals with large fractional bandwidth. Physics favors resonant devices. The receiver, then, can reject in-band spectrum as wide as 1 GHz while still receiving 90 percent of the signal. The wideband operation also enables relevant data-rates while maintaining ultra-low power spectral densities to mitigate interference with conventional narrow-band systems.”

This sounds like an interesting project. The phrase “reclaim this lost bandwidth without unintentionally jamming others” would indicate they will be looking at the impact on other users of the spectrum. These include satellite uplinks at 6 and 14 GHz, downlinks at 4 and 12 GHz, numerous fixed terrestrial microwave bands, and, in the future, 5G at 15 GHz.

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. As vice president of Broadcast Technology for NBCUniversal Local, H. Douglas Lung leads NBC and Telemundo-owned stations’ RF and transmission affairs, including microwave, radars, satellite uplinks, and FCC technical filings. Beginning his career in 1976 at KSCI in Los Angeles, Lung has nearly 50 years of experience in broadcast television engineering. Beginning in 1985, he led the engineering department for what was to become the Telemundo network and station group, assisting in the design, construction and installation of the company’s broadcast and cable facilities. Other projects include work on the launch of Hawaii’s first UHF TV station, the rollout and testing of the ATSC mobile-handheld standard, and software development related to the incentive auction TV spectrum repack.
A longtime columnist for TV Technology, Doug is also a regular contributor to IEEE Broadcast Technology. He is the recipient of the 2023 NAB Television Engineering Award. He also received a Tech Leadership Award from TV Tech publisher Future plc in 2021 and is a member of the IEEE Broadcast Technology Society and the Society of Broadcast Engineers.