Digital Headend System Integration

CONFIGURING THE DIGITAL HEADEND
When one starts specifying the digital headend, usually an overload of features and requirements are created to establish a full blown Digital Headend. A closer look at the end-users is necessary to establish what is needed ‘today’ and in ‘future’ stages. In the end it all comes down to finding the right balance, translating the set ambitions into a profitable business case. Identifying technical requirements and compliance to local and national regulations is only a part of the total exercise, finding the right match between the rollout of the digital headend and the launch of end-user services is key, to secure investment and revenue income.

TAKING THE RIGHT DECISIONS
When building a Digital Headend, operators are forced to take important decisions that form the foundation of the Digital Television Services ‘today’ versus ‘tomorrow’. One of these decisions is whether to build a traditional ASI based headend or implement a headend with an IP-core.

Building ASI based headends provides a wide selection of products to choose from, build on proven standards. One of the downsides of an ASI

based headend is the use of big matrixes, that limit the flexibility in configuration of services. Headends with an IP-core architecture provide this flexibility. All feeds are available on the IP-core and can be freely used as seen fit.
Redundancy is easily added and managed. Its scalability is unique in comparison to the more traditional ASI based headends. Movement in the market indicates that suppliers are moving their development towards IP, they are adopting the GbE interfaces, providing a wide selection of building blocks to choose from. This makes the IP-core headend a future proof solution.
Looking at the fast growing need for new end-user services, an IP based headend provides the flexibility needed for current and future requirements, providing the operator with all means to adjust quickly to the changing market.

BUILDING BLOCKS
When designing digital headends, five main areas need careful attention; Content Aggregation, Compression, Multiplexing, Access and System Management. In the following sections, some considerations and guidelines are given.

CONTENT AGGREGATION
Content is presented in different formats; the source can be feeds from Studio’s, Satellite, Terrestrial and direct IP through Gigabit Ethernet
(GbE) interfaces. Aggregation of these content types is mainly done by means of professional Integrated Receiver’s/ Decoder’s (IRD’s) with a dedicated IP output.
The use of IRD’s differ, depending on the use of scrambling or free to air services.
Redundancy plays an important role in the design. Flexibility in this matter is needed, to be able to add redundancy at any time necessary. For redundancy of IRD’s, the following methods may be used, being N:1, N:M or 1:1 depending on the end-user service and availability requirements.