What is ISDB-T
ISDB-T is ----
ISDB-T (Integrated Services Digital Broadcasting – Terrestrial) is a new type of digital broadcasting system for providing audio, video and multimedia services. ISDB-T system was standardized at the Association of Radio Industries and Businesses (ARIB) in Japan. ISDB-T uses a modulation method referred to as Band Segmented Transmission (BST) OFDM.
Requirements for Digitalization
Especially for Terrestrial broadcasting, mobile and handheld reception are important issues
The requirements described above were required in Japan.
Requirements for Digitalization ----- Solutions
Features of ISDB-T Transmission System
- ∗1 OFDM: Orthogonal Frequency Division Multiplex
- ∗2 SFN: Single Frequency Network
- ∗3 TMCC: Transmission and Multiplexing Configuration Control
ISDB-T system has the following several technical features, such as OFDM, Segmented Structure and Time Interleaving.
- OFDM is Robustness against interference and ghost.
- SFN (Single Frequency Network) is necessary to.
- Segmented Structure is required for Extensible, Partial Reception.
- Time Interleaving is required for Mobile Reception, Indoor Reception.
- Transmission and Multiplexing Configuration Control (TMCC) is required for Flexible, Versatile.
The reason Japan adopted the ISDB-T system for DTTB is following.
- The firstly, it is required that DTTB system is Robustness against Multi-path condition, is the strong requirement.
- Secondly, to save the frequency,in order to introduce the SFN(single frequency network), which is using frequency efficiently.
- The thirdly, in order to introduce the mobile service which is necessary for the DTTB services.
Segmented OFDM with time interleave
Feature of Japan's Digital Broadcasting system
|(1)||Flexibility of service: Interface between source coding and Multiplex is common interface (Transport Stream interface), so, any contents based on TS can be available.|
|(2)||Flexibility of transmission media: Optimized to each transmission media.|
|(3)||Terrestrial transmission system; For any reception type, such as fixed/mobile/handheld, adopt Segmented OFDM with time interleave.|
Segment transmission enables fixed, mobile or portable reception in one channel. DVB-T and ATSC require another channel for portable reception service, on the other hand, ISDB-T enables fixed/mobile/portable service in the same channel by one transmitter. This technology contributes to saving not only the frequency resource but also equipment cost. In addition to the above, time interleaved technology improves the signal quality in fading environment and realizes mobile or portable reception.
- Segmented OFDM; Possible to support fixed/mobile/handheld reception service
- Time interleave; reduce impulse noise and the degradation caused by fading