Media Links, in partnership with Seiko Solutions and Mainichi Broadcasting System, has successfully conducted a unique demonstration of IP transmission of the Integrated Services Digital Broadcasting –Terrestrial (ISDB-T) standard using Precision Time Protocol (PTP) over a single frequency network (SFN).
The three companies demonstrated the transmission of ISDB-T broadcast transport stream signals using PTP, a next-generation protocol for highly accurate time synchronisation. PTP support enables the distribution of synchronous signals which are a requirement for proper operation of an SFN. An SFN is a wireless network that broadcasts the same content on the same transmission frequency from multiple broadcasting stations. It is a means to extend the broadcasting coverage area without the use of additional frequencies. ISDB-T is a Japanese standard for digital television used by the country’s television networks.
A first demonstration of its kind in Japan using PTP master/slave synchronisation, it was concluded that it results in the straightforward implementation of delivering content to the transmitting stations over an SFN without major modifications of the SFN architecture. For uninterrupted broadcasting, especially in times of disasters, a more robust and resilient network is critical to distribute important public information. This technology implementation can be used for sending broadcast content over unstable paths including maritime/ocean transmission or long-distance low-quality paths. Therefore, building a microwave base station is not required and this infrastructure can be implemented relatively quickly.
Work will continue towards the commercial realisation of SFNs in Japan based on ISDB-T, IP and PTP.
The actual demonstration was carried out in two phases; a direct connection phase which verified the modulation/demodulation quality followed by a long-distance transmission phase which confirmed the timing stability of the content.
Media Links’ MDP3020 SFN IP media gateway was used in the demonstration. It uses the SMPTE 2022-2 standard for video signal distribution and supports hitless switching, enabling highly reliable IP transmission. Seiko Solutions provided the PTP equipment and Mainichi Broadcasting System operates the core terrestrial broadcasting network in Japan’s Kansai region.