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Software Defined Radio in Defence

Application of Software Defined Radio (SDR) in the Indian Defence Sector

Wireless Communication has always been an essential part of any defense service, whether the Army, Navy, or Air Force. However, new-age warfare requires the transition from traditional radio systems to a more advanced Software Defined Radio (SDR). SDR is certainly revolutionizing the way the Indian defense forces operate. It offers flexibility, and adaptability as well as a host of applications that are invaluable for modern warfare.

Let us explore the diverse applications of Software-Defined Radio for the Indian Defense Forces.

What is a Software Defined Radio (SDR)?

Software Defined Radio (SDR) is an advanced communication system where all the physical layer functions of a traditional radio have been replaced by software programs.

How does a Software Defined Radio (SDR) work?

To understand how an SDR works, we must first understand how a traditional radio system works.

Fundamentally, in any radio system, there are three major components – transmitter, receiver, and antenna. The transmitter system converts the audio into a signal, which is modulated with a radio carrier frequency. Furthermore, the signal is amplified and then transmitted in all directions. A receiver then receives this signal at a remote location. The receiver retrieves the information from the radio frequency and converts it into the original form.

Workings of a Basic Radio:

A basic radio communication system needs to perform multiple critical functions, such as amplification, modulation/demodulation, filtration, synchronization, etc. This helps to ensure clear and continuous communication between the radio equipment. In a traditional radio system, all the functions are performed by the hardware (circuit board) of the radio equipment, which brings about a plethora of challenges as the hardware is inflexible and unscalable. This is especially important when it comes to warfare, as the soldiers might be in remote areas.

Workings of an SDR:

In a Software Defined Radio, software modules, instead of hardware, perform all the vital functions, such as modulation, amplification, etc.  Software applications have thus replaced the circuit board of the traditional radio, thus giving it more flexibility and interoperability.

Benefits of Software Defined Radio for the Defense Forces

Here are some of the key benefits of using Software Defined Radios in the Defence Sector:

No Hardware Lifecycle:

Every hardware has a lifecycle and needs to be updated from time to time. You surely don’t use the mobile phone you used ten years ago. The same case applies to the radio equipment. In a traditional radio system, the hardware particularly has to be replaced periodically. However, in the case of SDR, all updates can be done on a software level.

Deployment Cost Reduction:

Software Defined Radio reduces the need for hardware upgrades and lowers implementation costs. If a new feature needs to be added, all that the developer needs to do is add a software module. This is quite contrary to the case of traditional radio equipment.


Using Software Defined Radios in defense forces leads to enhanced communication security. With a software-based architecture, SDRs can be implemented with advanced encryption and security protocols, which is just not possible in a traditional radio system.


Traditional radios can be of different makes, designs, and technologies. To ensure seamless communication, the legacy radio handsets should be of the same technology. However, with SDRs, as the processing is done on a software level, any handset type can be used to facilitate communication.

Waveform Portability:

The receiver of traditional radios supports only limited waveforms. However, as SDRs process waveforms on a software level, they can support multiple waveforms for different types of communication.

Software Defined Radios for the Indian Defense Forces

Communication plays a major role in any country’s defense systems. The goal is to transmit messages and data from one unit to another efficiently and clearly without being intercepted by enemies.

The existing communication system of the Indian defense force works on frequencies like HF, V/UHF, etc. These frequencies and their unique protocols create a secure network between different nodes under the tactical communication scheme.

The Indian Army has been using CNR (Combat Net Radio) for communication across terrains for quite some time now. However, the CNR can be used only in voice communications and has certain limitations. The Ministry of Defense (MoD) released a press statement on 18th February 2021 to address the changing requirements of the defense system. They further stated that they will revamp their existing communication systems to Software Defined Radios (SDRs) for the Indian armed forces.

Indigenisation of Software Defined Radios Under Atmanirbhar Bharat

The Ministry of Defense (MoD), on 26th July 2022, fast-tracked the development of SDRs in India. This was a vital step toward the use of SDRs in the Indian Defense Forces. The Directorate of Standardisation (DoS), IIT Kanpur, and DEAL/DRDO are the three major working on this project. They are pioneering the development of standards, design, manufacturing, and testing environments for SDRs.

It is essential to develop a standardized operating software environment (OE) and applications (waveforms) for the development of Software-defined Radios in India. This would enable multiple software vendors to develop and make SDRs interoperable. Consequently, MoD has given thumbs up to the project of developing a standard operating environment, which is called Indian Radio Software Architecture (IRSA). The development of IRSA will be handled by DRDO and DoS.

  • In March 2023, The Ministry of Defense (MoD) signed ten contracts with Bharat Electronics Limited (BEL) that cover contracts for the Indian Navy, Army, and Air Force. Among these contracts, one is the development of 1265 SDR portables for the Indian Navy with three variants. The three variants are Manpack (SDR-MP), SDR Fixed pack, and SDR-HH (Hand Held).
  • In July 2023, Alfa Defense Technologies Limited (ADTL) bagged a contract to supply 400 Software Defined Radios for the tank fleet of the Indian armored regiments. Prior to this, the tank fleet was using the legacy analog communication system.

Software Defined Radio is transforming the way the Indian Defense Forces communicate, adapt, and respond in an increasingly complex and dynamic security landscape. Its applications range from improving spectrum efficiency and interoperability to ensuring secure and adaptive communication in the face of evolving threats.

As technology evolves, SDR is all set to be a cornerstone of modern defense, empowering the Indian military to maintain its readiness and effectiveness in an ever-changing world. Embracing SDR technology is not just a choice but a necessity for the Indian Defense Forces in their quest to safeguard the nation’s security.

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