DMB (which stands for Digital Multimedia Broadcasting) is a system specification enabling the broadcasting of radio services in a digital form. This technology has its origins in the late 80s, when the original DAB (Digital Audio Broadcasting) was first developed as part of the Eureka 147 project. It is now coordinated by the World DMB Forum, which represents more than 30 countries.
DMB baseline features
DAB was the first standard to use Orthogonal Frequency Division Multiplexing (OFDM) modulation. This digital transmission technology provides enhanced performance in a multipath environment compared to existing AM and FM radio transmission systems.
The DAB spécification was based on MPEG Audio Layer II coding, which was then state of the art and is still a commonly used coding technology in radio and TV nowadays. Since then, several generation of coding technology have overtaken this standard, including MPEG Audio Layer III, (MP3) and DAB+ has integrated MPEG-AAC in its latest evolution (HE-AACv2) which provides much better quaklity for similar bitrates.
Another important innovation was the addition of video/multimedia capabilities to Digital Audio Broadcasting, allowing DAB to become a multimedia digital radio platform which was then renamed DMB.
Both DMB and DAB+ use the technical basis of DAB, and just add new applications, new transport protocols and a second error control coding layer. All three technologies can therefore be used alongside each other on one multiplex and basically use the same infrastructure.
WorldDMB recommends that DAB or DAB+ should be used for radio-centric services and that DMB should be used for services which include a video component.
– worldDMB: http://www.worlddab.org/
– ETSI: http://www.etsi.org/
– Wikipedia : http://en.wikipedia.org/wiki/Digital_radio