DVB-H

Digital Video Broadcasting-Handheld (DVB-H) is an open standard specified by the DVB Project to deliver TV and multimedia content to moving handheld devices such as mobile phones and PDAs. DVB-H is derived from the DVB-T standard for terrestrial broadcasting. To reduce the amount of power required for mobile reception, DVB-H uses time slicing, which means that specific content is transmitted at specific time intervals. This allows the handheld device to be switched on only at particular transmission bursts to save power. In addition, the error correction and mobility is improved. DVB-H can easily be implemented in excisting DVB-T networks. The drawback of time slicing is that it can cause a noticeable delay if the user switches from one channel to another.

Especially for DVB-H a new COFDM mode is introduced. This 4k mode uses 3409 carriers. The netto bit rate is lower than for DVB-T due to the additional error correction. The maximum bit rate is about 15 Mbit/s. Delivery of the content is based on IP datacast. This eases integration of DVB-H with a mobile network. The integration with a mobile network is further optimized because DVC-H can not only be used in the 6-8 MHz television channels but also in a a 5 MHz radio channel. The width of the radio channels of UMTS is also 5 MHz.

Spectrum for DVB-H
Being a derivation of DVB-T, DVB-H can in principle be used within the broadcasting bands: VHF Band III (174 - 230 MHz) and UHF Band IV/Band V (470 - 862 MHz), using the standardised 5, 6, 7, or 8 MHz channel bandwidths. However, there are some constraints that make usage of parts of these bands difficult.

• Band III has good propagation and building penetration characteristics. However, the signal wavelength of over 1 meter makes a rather long receiving antenna necessary which will be difficult to integrate in a handheld device.
• Band IV and V have propagation and building penetration characteristics that are still acceptable to offer large coverage. The size of the antenna is suitable for integration. However, in the upper part of Band V (above 750 MHz; channel 55) reception could be blocked by GSM900 transmission if the two are integrated in one mobile device.

Another possibility is to use L-band spectrum (around 1.5 GHz). In Europe, L-band spectrum is available for terrestrial broadcasting at 1452 - 1479.5 MHz. However, the use of the spectrum is at the moment restricted to DAB. In the US the band 1670-1675 MHz is already used for a trial. A drawback in using L-band could be poor indoor reception. There also might be a problem with GSM1800 transmission.