Europe Seizes Lead in Mobile TV

25th May 2004

The above link is to an article about DVB-H, the new DVB Project specification that will deliver digital TV and radio to mobile phones. DVB-H is already trialing in Berlin at the moment, and actual services are hoped to start in 2005, although this doesn't necessarily mean that the service will start in the UK by 2005.

DVB-H is supported by some of the major players like Philips, Nokia and Vodafone. The DVB-H system is based on the DVB-T specification (as used for Freeview), but has added modifications to dramatically reduce the power consumption required for reception of DVB-H to help maintain keeping the battery life of mobile phones as long as possible. DVB-H achieves its power consumption reduction by "time-slicing" where data is transmitted in short, fast bursts, and the receiver can then sleep until the it's time to receive the next slice of data. This enables the receiver to reduce power consumption by 90% compared to standard DVB-T receivers. Other modifications include a new 4K mode (DVB-T currently has 2K and 8K modes) and an additional layer of error correction coding for enhanced robustness.

The UK DAB industry frequently claims that DAB will be put into mobile phones, but comparing the DAB system to DVB-H shows just how poor the DAB system is, which is hardly surprising when you consider that DAB was developed in the late-1980s to early-1990s, whereas DVB-T was developed in the mid-1990s. For example, DAB can only use the MP2 codec for audio which requires a bit rate of about 192kbps for good quality audio (192kbps obviously has far better audio quality than 128kbps as used on DAB in the UK). DVB-H can use the far newer AAC codec which can provide good quality audio at 96kbps.

Also, DVB-H is twice as spectrally efficient as DAB (DVB-H: 11 Mbps in 8 MHz = 1.375 bits/s/Hz; DAB: 1.15 Mbps in 1.7 MHz = 0.676 bits/s/Hz, which makes DVB-H twice (1.375 / 0.676 = 2.03) as spectrally efficient as DAB), so combining the above figures, DVB-H can provide 4 times as many digital radio stations as DAB can at the same level of audio quality in the same amount of spectrum. Add to this the low audio quality on DAB in the UK and you have to wonder why on earth the mobile phone industry would want to bother with DAB when they can use the far superior DVB-H system instead?