TECHNICAL DIVISIONS
Communication Systems — Division 6
The Communication Systems Division develops and demonstrates new technology to enhance and protect the capabilities of the nation’s global defense networks. The efforts draw on a core expertise in radio frequency (RF), fiber and free-space optics, and communications processing technologies to address the needs of next-generation satellite, airborne, and terrestrial networks. Emphasis is placed on synthesizing system architectures, developing component technologies, building and demonstrating end-to-end system prototypes, and then transferring this technology to industry for deployment in operational systems. The diverse elements of this program include characterization of RF and optical channels, and research and prototyping of protected satellites and terminals. The division is extensively involved in field experimentation and measurement campaigns to verify algorithms and architectural concepts in operational environments.
| Groups |
Group 63—Wideband Tactical Networking
The Wideband Tactical Networking Group develops enabling communications and networking concepts, technologies, and prototypes for mobile tactical military forces. The group is currently developing two types of advanced satellite communications (SATCOM) terminal prototypes. The first is a mobile ground terminal that can connect to multiple military satellites, including those that are able to maintain communications services during hostile electronic attack. The second type of prototype terminal supports high-rate data readout from long-range unmanned aerial vehicles. These system prototypes are used in a variety of demonstrations and field experiments, integrating a wide range of advanced technologies including multiband antenna feeds, low-profile antennas, antenna positioning systems, linear-efficient amplifiers, novel waveforms, advanced networking techniques and algorithms, and programmable modems. The multidisciplinary expertise required to complete these prototypes has allowed the group to tackle a diverse set of challenges related to algorithms and radios for mobile communication.
The group also conducts extensive research and experimentation on wireless networks. Activities include mobile ad hoc network performance prediction and a series of efforts addressing the challenges of heterogeneous networks. These efforts include investigating the application of network coding to heterogeneous link types, experimentation to address the challenges of interconnecting disparate mobile networks, and studies to determine policy settings that would allow network data to transit across networks. To facilitate these activities, the group has developed and employs a variety of network simulation and emulation tools. These tools provide a unique environment to evaluate emerging networking concepts, and some of the tools have been distributed broadly throughout government and industry.
Group 64—Advanced SATCOM Systems and Operations
The Advanced SATCOM Systems and Operations Group is involved in a synergistic combination of research, proof-of-concept test beds, and system engineering and application efforts focused on the goals of enhancing the capacity, the robustness to interference, and the flexibility of future generations of communications satellites, as well as line-of-sight radio communications systems and free-space optical communications. Current research is concentrating on the design and performance of advanced waveforms (including higher-order signaling constellations and iterative demodulation/decoding), the construction of flexible, adaptive wideband frequency plans, robust acquisition and tracking techniques, dynamic resource-allocation protocols, and advanced networking strategies. Promising research results are verified in hardware and software proof-of-concept implementations that provide quantitative performance data as well as complexity information. The group's system engineering activities synthesize innovative architectures and apply new concepts and technologies to specific communications programs in the national interest.
Group 65—Airborne Networks
The Airborne Networks Group develops architectures, technologies, and fundamental research solutions to enable the next generation of airborne networks. Airborne networks carry tactical and sensor data between multiple aircraft within a region of operation, provide range extension and backbone connectivity for disparate air and surface nodes, and provide protected communications for low-observable aircraft operating in adversarial environments. Unlike commercial wireless networks, airborne networks cannot rely on a ground-based infrastructure to enable single-hop wireless communications to a cell tower. Hence, the group conducts fundamental research to understand the performance limits of mobile ad hoc networks and develops technologies that bring practical systems closer to achieving this capacity.
The varied and stressing operational environment, rapid aircraft speeds and maneuverability, the large distances between neighboring aircraft, as well as the high costs of platform integration, generate additional challenges for airborne communications. The Airborne Networks Group designs cutting-edge systems capable of robust operations in the airborne environment. Design solutions are developed at all layers of the network stack and are implemented as hardware/software prototypes. The researchers use a combination of technical analysis, modeling, simulation, emulation, prototype development, and flight testing to develop new communication systems and to evaluate and predict their performance. Research and design areas include interference-resistant and bandwidth-efficient modulation and coding, multiuser detection, topology design and management, multiple-access communications, dynamic scheduling and resource allocation, network coding, efficient and robust unicast and multicast routing, heterogeneous networking, delay-tolerant networking, network architecture and design, and network management as they apply to this unique and dynamic environment.
Group 66—Advanced Lasercom Systems and Operations
The Advanced Lasercom Systems and Operations Group conducts analysis, design, demonstration, and testing of optical communications systems over free-space channels. Recent initiatives focused on airborne lasercom systems supporting data transfer from tactical ISR (intelligence, surveillance, and reconnaissance) platforms and included identifying and validating techniques for mitigating signal power fluctuation due to atmospheric turbulence. Group capabilities include high-fidelity atmospheric modeling and simulation, and the development of multi-Gb/s modems; pointing, acquisition, and tracking systems; high-speed electronic coding and interleaving schemes; and network-standard interfaces. The group works with government and industrial partners to help expedite the transfer of capability to operational systems.
Group 67—Optical Communications Technology
The Optical Communications Technology Group develops advanced laser communications technology for use in a wide range of challenging environments. Research in sensitive, single-photon-counting detector arrays, inertial sensors, novel modulation formats, and coding supports the development of communications systems with relevance to national needs. These technologies support the most sensitive optical communications links ever developed, enabling communication of several bits per detected photon across vast distances or through challenging environments. Using some of these technologies, the group is also investigating unique capabilities based on the quantum properties of light.
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