Dvbix

DVB-H (Digital Video Broadcasting - Handheld) is a technical specification for bringing broadcast services to handheld receivers. DVB-H was formally adopted as ETSI standard EN 302 304 in November 2004. The DVB-H specification (EN 302 304) can be downloaded from the DVB-H Online website. The major competitor of this technology is Digital Multimedia Broadcasting (DMB).

It is the latest development within the set of DVB transmission standards. DVB-H technology adapts the successful DVB-T (Digital Video Broadcasting - Terrestrial) system for digital terrestrial television to the specific requirements of handheld, battery-powered receivers. DVB-H can offer a downstream channel at high data rates which can be used standalone or as an enhancement of mobile telecoms networks which many typical handheld terminals are able to access anyway. Time slicing technology is employed to reduce power consumption for small handheld terminals. IP datagrams are transmitted as data bursts in small time slots. Each burst may contain up to 2 Mbits of data (including parity bits). There are 64 parity bits for each 191 data bits, protected by Reed-Solomon codes. The front end of the receiver switches on only for the time interval when the data burst of a selected service is on air. Within this short period of time a high data rate is received which can be stored in a buffer. This buffer can either store the downloaded applications or playout live streams. The achievable power saving depends on the relation of the on/off-time. If there are approximately ten or more bursted services in a DVB-H stream, the rate of the power saving for the front end could be up to 90%. DVB-H is a technical system which was carefully tested by the DVB-H Validation Task Force in the course of 2004 (see ETSI Technical Report TR 102 401).

DVB-SH (satellite services to handheld devices) is a hybrid (satellite/terrestrial) architecture using S band. A similar architecture has been already used in S-DMB, XM Satellite Radio, Sirius Satellite Radio, MobaHo! but DVB-SH promises to be more powerful. It incorporates a high power geostationary satellite for outdoor and light indoor coverage integrated with a terrestrial repeater (low power gap-filler) network for indoor coverage in urban areas.

Alcatel expects to deliver DVB-SH terrestrial repeaters in 2007 and to launch, with Eutelsat, a DVB-SH satellite (covering Europe) in 2008. Chip maker DiBcom is designing a chipset that will be compatible with the DVB-H standard working in the S-Band, Sagem is developing DVB-H phones that support both UHF and S-Band. At the moment it’s not an official DVB Forum standard. The DVB Technical Module had already launched a Study Mission on SSP (Satellite Services to Portable Devices) and in June 2006 TM-SSP started to develop standards. DVB Forum plans to release definitive standard during 2007.

French Agence de l’innovation industrielle is now financing this effort through TVMSL, a project leaded by Alcatel that plans to develop a DVB-H standard suitable for hybrid satellite and terrestrial transmission. Other partners involved in TVMSL are Sagem, Alenia, RFS, Philips, DiBcom, TeamCast, UDcast, CNRS, INRIA, CEA-LETI.