F.4 SDC data entities and setup for alternative frequency signalling

The following SDC entities are used to carry the alternative frequency and announcement signalling:

•Alternative frequency signalling: Schedule definition data entity - type 4.

•Alternative frequency signalling: Region definition data entity - type 7.

•Alternative frequency signalling: detailed region definition data entity - type 13.

•Alternative frequency signalling: Multiple frequency network information data entity - type 3.

•Alternative frequency signalling: Other services data entity - type 11.

To set up the alternative frequency signalling feature, the broadcaster will typically perform the following steps:

1)If some alternative frequencies are only valid at certain times, provide up to 15 schedules (SDC data entities type 4), each identified by its unique Schedule Id; to explicitly indicate that some frequencies are available all the time, it is recommended that a "24 hours, 7 days a week" schedule is signalled.

2)If some alternative frequencies are only valid in certain geographic regions, provide up to 15 region definitions (SDC data entities type 7 and 13), each identified by its unique Region Id.

3)If alternative frequencies are available for the current DRM multiplex or at least some services, provide SDC data entities type 3 for all lists of frequencies; each list may point to alternative frequencies carrying the identical DRM multiplex in a synchronous way (seamless alternative frequency checking and switching may be performed by the receiver) or carrying some or all services of the current DRM multiplex with different channel parameters and/or not synchronized (checking and switching will interrupt the service presentation); each list of frequencies may be restricted to a geographic area and/or a schedule by referencing one SDC data entity 4 and/or 7 and/or 13.

4)If alternative frequencies are available for individual services of the current DRM multiplex using different DRM Service identifiers or being carried on a different broadcast system (e.g. DAB or FM-RDS), provide SDC data entities type 11 for all lists of frequencies; each list can indicate one other service identifier, the broadcast system type and the "same service" flag along with a list of frequency values;

if only a service identifier is specified (without any frequencies), the receiver has to scan for an available frequency; each list of frequencies may be restricted to a geographic area and/or a schedule by referencing one SDC data entity 4 and/or 7 and/or 13.

A broadcaster can choose to group the frequencies by region by using a common region id per group even if no "Alternative frequency signalling: Region definition data entity - type 7" or "Alternative frequency signalling: detailed region definition data entity - type 13" is provided for a particular Region Id. This allows receivers to check alternative frequencies within the same group first (defined by the Region Id) before checking other groups - the current position of the receiver does not need to be known.

F.5 SDC data entities and setup for announcement

The following SDC entities are used to carry the Alternative Frequency and Announcement signalling:

•Alternative frequency signalling: Schedule definition data entity - type 4.

•Alternative frequency signalling: Region definition data entity - type 7.

•Alternative frequency signalling: detailed region definition data entity - type 13.

ETSI

•Alternative frequency signalling: Other services data entity - type 11.

•Announcement support and switching data entity - type 6.

To set up the announcement signalling, the broadcaster will perform the following steps:

1)Set up all required SDC data entities type 6, indicating which types of announcements are provided and which are currently active, and which internal DRM services are linked to which services carrying the announcement content (services in the same DRM multiplex or other services).

2)If some alternative frequencies for announcements are only valid at certain times, provide up to 15 schedules (SDC data entities type 4), each identified by its unique Schedule Id; to explicitly indicate that some frequencies are available all the time, it is recommended that a "24 hours, 7 days a week" schedule is signalled.

3)If some alternative frequencies for announcements are only valid in certain geographic regions, provide up to 15 region definitions (SDC data entities type 7 and 13), each identified by its unique Region Id.

4)For every "Announcement Id" value provided by a SDC data entities type 6 (thereby linking to another service), there should be at least one SDC data entity type 11 (with the "Short Id/Announcement Id flag" being set to 1 and using the same "Announcement Id"), providing the broadcast system type, service identifier and frequencies of the other service.

ETSI