NATO Eyes Full-Duplex Radio Communications

NATO’s Science and Technology Organization took notice of the military potential of same-frequency simultaneous transmission and reception, or SF-STAR, capability employed with full-duplex radio technology, and in 2017 formed an exploratory team to examine the potential use in tactical communications and electronic warfare.

The exploratory team “found relevance” in the emerging in-band full-duplex transceiver technology. “The feasibility of full-duplex operation has been convincingly proved for lower-power commercial mobile communication systems in a laboratory environment,” stated a report from the Science and Technology Organization (S&TO). The team recommended additional research to confirm full-duplex radio communication “under realistic conditions in field environments for a selection of relevant operational scenarios,” including applicability at lower military radio frequencies—such as high frequency, or HF; very high frequency, or VHF; and ultra-high frequency, or UHF, applications—the S&TO reported.

For the military, the ability to have a technology that can simultaneously transmit and receive radio signals on the same frequency would be a critical function for NATO forces, especially given the increasing demands on spectrum management as well as persistent electronic warfare threats. The tactical communication services provided by NATO-led operations or initiatives—such as the NATO Response Forces, Very High Readiness Joint Task Force, Enhanced Forward Presence and Federated Mission Networking, all of which are gaining in prominence, the S&TO said—could benefit greatly from application of SF-STAR, full-duplex communications.

The exploratory team found that most of the experimental research on full-duplex communications so far had been limited to the 2.4 gigahertz (GHz) industrial, scientific and medical (ISM) band. In addition, self-interference cancellation (SIC) capabilities, needed to enable full-duplex communication, are also improving. The team observed that researchers from different universities commonly employed a two-staged SIC approach, one that functions in the analog domain and the other in the digital domain.

“State-of-the-art prototypes around the world achieve beyond 100 dB [decibels] of total self-interference cancellation, even with rather large operation bandwidth of up to 80 MHz [megahertz],” the S&TO reported.

Employing a research task group earlier this year, the S&TO began a more comprehensive four-year study to: (1) further identify military applications for the emerging full-duplex technology; (2) assess state-of-the-art SIC solutions for tackling the signal interference problem, both in the analog and digital domains; (3) identify commercial concepts that could apply to the military domain and frequencies.

NATO’s research task group also is looking at how to pursue frequency agnostic solutions, how to prepare a common multinational demonstrator and how to implement commercial off-the-shelf software-defined radio technology into SF-STAR and full-duplex technology.

“The success of future NATO operations relies more than ever on new real-time services going hand-in-hand with increased data throughputs and with robustness against electronic warfare,” the report from S&TO stated. “Therefore, future tactical communication and electronic warfare technologies must aim at using the full spectral capacity and providing NATO an advantage in the tactical environment.”