Applications of Software-Defined Radio in the Military
For soldiers on the battlefield and decision-makers in command centers, secure, real-time, and accurate information is critical to military operations, strategic planning, and tactical decision-making.
Advanced wireless communication networks rely on complex radio frequency (RF) and signal processing technologies working in tandem to form reliable communication systems that enable users to transmit information with the touch of a button.
Throughout military communication history, numerous incompatible radios have emerged for various purposes, such as airborne links, satellite communications, relay base stations, emergency transmitters, and specialized applications like drone operations. Each radio link plays a vital role, and the absence of even one could put a team at a disadvantage. However, the cost of radios - in terms of size, weight, and battery requirements - poses significant challenges. As new requirements and links are added, the problem becomes increasingly complex.
There is a growing need for a universal, full-duplex radio module that can be deployed across all platforms and reconfigured dynamically in the field. Such a module would reduce logistical burdens, enhance flexibility and versatility, improve efficiency, and extend battery life, offering significant advantages in size, weight, and power (SWaP).
Yet, realizing this universal radio concept has proven far more difficult than anticipated, particularly in designing a suitable analog front-end (AFE). Until recently, practical AFEs for multifunctional radios required an array of overlapping parallel channels, each covering a specific frequency band with bandwidth matched to the target signal format. This approach incurred high costs in terms of circuit board space, weight, and power consumption.
Software-Defined Solutions
Software-defined radio (SDR) technology, which adapts to various physical layer formats and protocols and encrypts data via software-run processors, is ideally suited for military applications. Users can dynamically control frequency, modulation, bandwidth, encryption functions, and waveform requirements.
SDR also allows for the flexible integration of new waveforms and functionalities without hardware upgrades or replacements. Soldiers can use SDRs for data access and communication with command centers, as well as to create wide-area sensor/mesh networks for position detection and communication among combat units.
The most critical component of an SDR is the transceiver, which must support an extremely wide RF range adjustable via software. It must also accommodate frequency-division duplexing (FDD) and time-division duplexing (TDD), while delivering high levels of range and reliability - even in noisy environments. Additionally, the device must operate at low power to minimize battery consumption.
Highly integrated mixed-signal RF ICs have enabled the design of smaller, lighter, and more power-efficient broadband SDRs. However, the true challenge lies in the ultra-wide bandwidth characteristics of the SDR's AFE. Designing spectrum-specific front-ends for each band remains complex and costly, often resulting in final products that fail to meet SWaP requirements.