DVB-H technology is a superset of the DVB-T standard for digital terrestrial television, with additional features to meet the specific requirements of handheld battery-powered receivers, such as :
- enabling services for portable and mobile usage;
- accessing services while moving at high speed with seamless handover;
- maximizing the compatibility with DVB-T, to allow sharing of network and transmission equipment.
DVB-H baseline features
DVB-H is designed to work in the UHF, VHF and L bands. It can coexist with DVB-T in the same MPEG multiplex and offers a downstream channel at high data rates which can be used either standalone or as an enhancement of mobile telecommunication networks.
Its main innovations compared to DVB-T are
- Time slicing : it used to reduce power consumption for battery powered terminals: digital data is transmitted within IP datagrams as time-limited bursts. 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 for continuous usage.The achievable power saving depends on the relation of the on/off-time.
- Error correction : provisions have been added to make transmissions more robust, such as FEC at the datagram level and in-depth frame interleaving at the modulation level.
The set of DVB specifications for IP datacasting (DVB-IPDC) is a set of systems layer specifications initially designed for DVB-H, but that can be used in any other IP capable system.
In short, with regard to mobile TV, these specifications define what is delivered, how it is delivered, how it is described, and how it is protected. They cover system architecture, use cases, DVB PSI/SI signalling, electronic service guide (ESG), content delivery protocols (CDP), and service purchase and protection (SPP). All of these have now been published as formal ETSI standards.