Breaking: IIT Kanpur clears D2M Broadcasting; says no harmful interference or device overheating

A comprehensive series of technical tests commissioned by Prasar Bharati and conducted by the Indian Institute of Technology Kanpur (IIT-K) have found that Direct-to-Mobile (D2M) broadcast technology operating in the 470–582 MHz band does not cause harmful interference to mobile networks and abnormal heating in smartphones.

India’s ambitious Direct-to-Mobile (D2M) broadcasting initiative is set to move into rollout phase by mid-2026, with commercial launches expected toward the end of next year. D2M’s ability to transmit high-quality content directly to mobile phones could ease bandwidth pressure on telecom networks and provide new monetization avenues for broadcasters.

The results, reviewed and certified by NABL-accredited Aracion Technology Pvt. Ltd. in Bengaluru, mark a significant step forward in India’s push to deploy next-generation broadcast systems for mass content delivery.

The public broadcaster had approached IIT Kanpur earlier this year after several stakeholders raised concerns about potential interference with 4G/5G mobile networks and possible device overheating when D2M broadcasts are active. IIT Kanpur, which has been partnering with Prasar Bharati since 2019 on Next-Gen Digital Terrestrial Broadcasting standards, conducted test measurements on November 14, 2025, at a Telecommunication Engineering Centre (TEC)-designated facility operated by Aracion Technology.

The testing covered two major domains: thermal behaviour of D2M-enabled smartphones during audio-video playback and interference impact on user equipment (UE) receiver sensitivity across LTE and 5G NR bands. The smartphone used was the fully ATSC 3.0–compliant Tejas Networks “MarkOne” device, while the 40W Broadcast Radio Head (BRH), model YOGA40W01, was evaluated as the D2M transmitter.

No abnormal temperature rise in D2M-enabled smartphones

Thermal tests compared temperature profiles of the MarkOne smartphone during D2M playback with regular cellular streaming of similar-resolution content. Using a high-specification Fluke TiS60+ thermal camera, engineers recorded surface temperatures on both front and back panels at intervals up to 180 minutes.

The D2M playback maintained back-side temperatures between roughly 33.6°C and 34.7°C, while the front surface ranged from 35°C to 35.7°C. These readings closely matched those observed during playback over the 4G cellular network, where back-side temperatures remained around 32°C–33.5°C and front temperatures stayed near 33°C–35.2°C. The device maintained stable thermal behaviour under both conditions, with no abnormal heat buildup observed during prolonged D2M operation.

The laboratory certified the smartphone as passing all thermal acceptance criteria as defined in the test methodology.

No degradation of 4G/5G network performance due to D2M signals

The more critical question involved testing interference between the D2M broadcast signal and mobile network operations, particularly in 3GPP-defined IMT bands such as n71, n28 and n5. Tests were conducted in both conducted and radiated environments using industry-standard equipment including a Keysight UXM 5G test system, calibrated OTA chambers, and LPDA antennas.

Under baseline conditions without interference, the smartphone demonstrated receiver sensitivity levels of –90 to –92 dBm across the tested bands. When the D2M transmission was introduced—configured at standardized out-of-band blocker levels prescribed by 3GPP—the sensitivity remained unchanged. The tests recorded zero desensitization in both conducted and radiated setups.

Further, downlink and uplink throughput remained above 95% of baseline performance even when the interfering D2M signal was radiated at full-power 40W output. Engineers also confirmed that the D2M device transmitted a valid 8 MHz ATSC 3.0 waveform during all tests.

The BRH transmitter itself was subjected to spurious emission analysis across frequencies up to the fifth harmonic of the upper broadcast band edge. The highest spur observed was –54.9 dBm, significantly lower than the –36 dBm limit applicable in the 30 MHz to 1 GHz range. All measured spurious emissions were comfortably below 3GPP Category B base station limits.

The test reports confirm that the D2M transmission meets the 3GPP-defined blocking and spurious emission requirements specified in TS 38.101, TS 38.521, TS 36.101 and TS 36.521 for LTE and 5G NR devices. Aracion’s laboratory, accredited under ISO/IEC 17025:2017 and designated by the Department of Telecommunications’ Telecommunication Engineering Centre (TEC), certified the results on November 13, 2025.

The final conclusion states that the D2M Broadcast Radio Head operating in the 470–582 MHz frequency band “does not introduce any harmful interference or degrade the performance of IMT user equipment in commercial cellular bands” and that thermal behaviour of D2M-enabled smartphones remains within acceptable operational boundaries.

The Ministry of Information and Broadcasting (MIB) has appointed Ernst & Young (EY) as the project management consultant to design the national D2M roadmap, including a sustainable revenue and business model. The initiative, led by Prasar Bharati, aims to enable multimedia content — including videos, news, and emergency alerts — to be broadcast directly to mobile devices without relying on internet connectivity, functioning much like FM radio for the digital age.