There is little disagreement that electromagnetic spectrum (EMS) is vital to both the nation's economic growth and national security, and that more and more demands are being placed on this finite resource. Radio frequency bands form the over-the-air "circulatory system" for a wireless world that is growing exponentially, delivering everything from secure national defense communications to mobile communications for consumers and powering the Internet of Things.
The broad challenge facing governments and industry is how to meet such rapidly growing demands for a finite national resource. This includes, of course, the coveted AWS-3 spectrum bands that are prized by business and consumer uses, and at the same time needed to ensure the U.S. retains electromagnetic dominance in what is being studied as a new domain of warfare.
Military operations are increasingly dependent upon access to spectrum to execute their missions, ranging from maintaining reliable and secure communications among deployed forces – on the ground, in the air and at sea – with those assessing the tactical environment, exercising command and control authority, and relaying vital information in real time.
As part of the administration’s goal, the Department of Defense (DoD) is working to reallocate a total of 500 MHz of spectrum for auction to commercial interests. In March, the DoD acknowledged the success of a 2015 federal spectrum auction that included the 1755-1850 MHz bands used by the military. "I think today we’re in a good spot," CIO Terry Halvorsen said in congressional testimony on the department’s fiscal FY2017 IT budget request. "We did well with the last auction and the money is there to change where DoD can move and share spectrum. What I worry about right now is that the private demand for spectrum is going to exceed our ability to keep pace. We could, if we’re not careful, put some national systems at risk."
The Army Communications Modernization Program is a good example of farsighted leadership in avoiding such risk by supporting more efficient use of the finite spectrum environment. Army leaders have long recognized the need for maintaining EMS dominance for secure communications and established rigorous industry challenges to encourage development of communications innovations. This approach led to the introduction of software-defined radios (SDRs) ― groundbreaking technology that can be applied to the challenge of limited spectrum.
Given the essential nature of EMS to national defense, developing technology solutions that will make the most efficient, resilient and secure use of spectrum also must be Job One for the nation's technology players. Here are a few suggestions for starting lines of attack:
- Share spectrum. The Defense Advanced Research Projects Agency (DARPA) has announced challenge grants for research to improve military use of spectrum. It also has several programs of its own, including RadioMap, which is aimed at reducing congestion and interference in complex environments, and the Shared Spectrum Access for Radar and Communications (SSPARC) program. SSPARC is an effort to co-locate communications with radar, essentially embedding communications signals within the bands used for radar. Radar and communications jointly consume the majority of the most desirable spectrum bands below 6 GHz. It seeks to develop sharing technology that enables sufficient spectrum access within this desirable range for radar and communications systems to accomplish their evolving missions.
- Make better use of existing spectrum. The advances in military HF radios, such as those developed by Harris, including the Falcon II® AN/PRC-150(C), the Falcon III RF-7800H-MP Wideband HF/VHF Tactical Radio System, and the RF-5800H-MP HF Manpack Radio point the way to how continued technology innovation can provide soldiers with secure voice and data communications beyond line of sight in the field and operate efficiently at the HF 3-30 MHz spectrum range.
- Dynamically allocate spectrum.Already, the Harris-developed AN/PRC-117G has the capability to find available spectrum on the ANW2 waveform. Continuing to develop radios this development with more advanced waveforms and capabilities will contribute to answering the challenge using the SDR approach.
- Software-defined radio (SDR) advancements. An important key to maximizing spectrum will emerge from the Army’s commitment to modernization in radio communications by pursuing further advances in SDR technology with its industry partners. SDR-enabled technology can do far more than communicate using spectrum, albeit more efficiently than earlier generations of radios. Already, SDRs can detect, locate, transmit, and move between various bands of spectrum.
Such flexibility also supports a wider range of capabilities, including enabling operators to target, jam and defeat enemy signal jamming, and gather and share intelligence with friendly sources at longer distances. In effect, the SDR is a foundation technology for dynamic spectrum access systems with cognitive, or "smart radio" functionality such as the advances being pursued under DARPA initiatives.
As a result, the Army's commitment to modernization will enable our military to evolve capabilities while making better use of this finite valuable resource called spectrum.
Army Maj. Gen. Dennis Moran (ret.) is the vice president of Government Business Development for Harris Corporation.