The pursuit of indigenous Software-Defined Radios aligns with the Atmanirbhar Bharat initiative and removes India’s dependence on foreign radios. The development of the Indian Radio Software Architecture (IRSA) in 2025 will create the foundation for truly integrated, multi-domain military communications. AI-enabled SDRs, meanwhile, can give indigenous defence manufacturing an edge.

The ongoing operationalisation of Software-Defined Radios (SDRs) in the Indian Air Force aligns with the overarching concept of Net-Centric Warfare (NCW). The IAF began pursuing an operational airborne SDR in 2013, which subsequently led to the development of the Indian Radio Software Architecture (IRSA) in 2025.[i] These are not separate milestones but successive stages of the same network-centric transformation. The former addressed the immediate operational requirement to connect aircraft securely in combat. The latter established the national software standard that will allow future indigenous SDRs across the Air Force, Army and Navy to communicate through common, portable and certifiable waveforms, creating the foundation for truly integrated, multi-domain military communications. The concept of SDR has not remained limited to the Tri-services but has also been extended to Para-military forces. This brief traces the evolution of IAF’s efforts to enable secure, resilient and jam-free military-grade communication, and outlines its operational implications and deliverables.

SDR, as the name suggests, is driven by software rather than dominated by hardware components. The concept of a radio whose frequency, waveform and encryption are set by software rather than by fixed circuitry began in the 1980s at the US Department of Defense laboratories and at E-Systems Inc. in Texas. Joseph Mitola coined the term ‘software radio’ in the early 1990s, and soon thereafter the Defense Advanced Research Projects Agency’s (DARPA) SpeakEasy programme built the first working military demonstrator: a single radio emulating more than 10 existing military radio types across a wide frequency band.[ii] The concept did not stay limited to the military. The North Atlantic Treaty Organization (NATO) built its own multi-vendor SDR standard, and the US National Institute of Justice has documented SDR linking police, fire and emergency medical services domestically.[iii]

India’s own SDR programme spans across its security architecture, encompassing all military and paramilitary forces. The Ministry of Defence signed its first major SDR contract, worth over Rs 1,000 crores, in February 2021, jointly developed by the Defence Research and Development Organisation (DRDO) and Bharat Electronics Limited (BEL), with interoperability features covering an airborne variant, a naval variant and handheld sets.[iv]

A Rs 5,498-crore, 10-contract package in March 2023 added 1,265 SDR portables for the Navy.[v] In February 2024, the Air Force signed its own contract with BEL for a man-portable SDR designed for ship-to-ground, ground-to-ground and ground-to-air communication during critical operations.[vi] The Coast Guard followed in February 2025 with a Rs 1,220.12-crore contract for 149 SDRs,[vii] and the Army signed its first indigenous SDR contract in October 2025.[viii] In the same month, the DRDO released IRSA Standard 1.0, India’s first national standard for SDRs to enable interoperability and standardisation.[ix]

From Analogue Radios to SDR: The IAF’s Communication Trajectory

In the 1930s and 1940s, communication ran on single-function analogue radios-elementary wireless communication in high frequency (HF) and very high frequency (VHF), since the inception of the IAF. From the 1950s, it ran on tropospheric-scatter links shared across the Services, with no dedicated network linking radar posts to command centres.[x]  The 1962 and 1965 wars exposed this gap. In March 1971, Air Headquarters began planning the Air Defence Ground Environment System (ADGES), India’s first radar-to-command network. ADGES matured through the 1970s and remained the IAF’s principal network for three decades, though its backbone stayed analogue. Kargil in 1999 added the lesson that joint Army–Air Force communication had to be planned from the outset of an operation.[xi]

The break came in September 2010, when the IAF commissioned the Air Force Network (AFNET), a Rs 1,077-crore Internet Protocol (IP)/Multi-layer Switching Protocol (MPLS) digital grid on optical fibre, built to replace 1950s-era troposcatter.[xii] IACCS was designed to ride the AFNET backbone, fusing ground and airborne sensors, weapons, and command nodes into one air situation picture.[xiii]

In parallel with the operational fielding of the IACCS, the IAF issued a global tender in 2006 for a pilot project on an Operational Data Link (ODL). It is pertinent to mention that the AFNET, on which IACCS itself rides, had already been under field testing in this period before its launch in 2010. The pilot contract for the ODL was awarded a year earlier, in January 2009, amid competing bids from three global companies. The pilot project sought to demonstrate the feasibility of networking aircraft, including fighters, transports, helicopters and surveillance platforms such as the Phalcon Airborne Warning and Control System, within the concept of IACCS.[xiv]

The experiences of the pilot programme led to the development of the airborne SDR project in the 2010s, which in turn........

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