Digital Terrestrial Broadcasting: Innovation and Development or a ...

94 COMMUNICATIONS & STRATEGIESTwo main approaches can be adopted to allocate resources in amultiplex block:• Static allocation. With this form of allocation, a fixed amount ofcapacity is assigned to different content providers. The multiplex functiononly multiplexes the input and generates the output stream.• Dynamic allocation. Here, whole or part of the capacity is allocateddynamically. Different approaches can be used to allocate resources todifferent content providers but the important thing is that the amount ofcapacity allocated may change over time.The degree to which static or dynamic allocation is employed depends onthe regulations applying to the assignment of content and multiplex blocks.Various approaches can be used to organise a multiplex block and assignavailable capacity, and they all have their own advantages and drawbacks.The multiplex block can be organised by the content provider, infrastructureprovider or by a totally independent provider. The resources in one multiplexblock can be assigned to one HDTV service or multiple lower-qualityservices. The following section outlines HDTV versus multi-serviceallocations, and then looks at the different forms of multiplex operation.HDTV versus multi-service allocationThe increased capacity available in digital broadcasting can be used totransmit:- a number of TV services of lower quality than HDTV such as SDTVquality , for example,- a combination of TV services with SDTV quality and new servicessuch as data, audio or video services, for example, or- one single HDTV program and its program-related data,in the same frequency bandwidth as an analogue TV channel. Hereafter, thefirst two cases are known as multi-service allocation, and the latter as HDTVallocation.When resources are used for transmitting HDTV-quality signals, thedigitalisation of broadcasting will not bring about any radical changes inmarket organisation. There will still be a one-to-one relationship between aTV service and the frequency bandwidth of a TV channel. The onlydifference is that the technical quality of the transmitted pictures in terms of,for example, picture resolution, audio quality and additional data, willincrease substantially compared to analogue broadcasting.