The report of TG 6/8, in Chapter 3 - Planning principle, methods and approach, § 22.214.171.124 to the first session of the RRC gave considerable information about four planning scenarios which were intended to indicate that any general planning philosophy wish expressed by an administration could be satisfied. There is, of course, no intention to imply that the detailed requirements submitted by administrations can all be satisfied. In fact, it is extremely unlikely that all requirements can be satisfied because there are natural limitations on the capacity of the available spectrum and it is to be expected that the initial requirements from administrations will exceed that natural capacity. Compromises will therefore need to be made by administrations in order to achieve a satisfactory plan.
The planning scenarios in the TG report are intended to respond to a wider range of planning options than are likely to be required by administrations. This is necessary if there is to be certainty that all general planning philosophies can be dealt with. However, it means that only very limited attention needs to be given
to planning scenario 1 which seems unlikely to be needed in practice as it can be replaced by planning scenario 2 with no loss of generality.
This is because the intention of planning scenario 1, which was to allow for the case where an analogue station remains operational for an indefinite period, can be achieved by planning scenario 2, which allowed for continued protection of an analogue station with a subsequent change to digital operation in the same channel at the end of a transition period. If an administration does decide not to convert an existing analogue station to digital operation, it just means that the transition period for that station is extended indefinitely.
It may also be the case that scenario 4, which allowed for the planning of digital stations with no constraints imposed by reuse of existing analogue channels, is unlikely to be of general value. This is because if there is no reuse of existing (or planned) channels, it becomes almost impossible to ensure protection of both analogue and digital stations during the transition period, especially in the case where the administrations of neighbouring countries have different timetables for effecting the transition from analogue to digital.
However, there is one situation in which the application of scenario 4 could become very important. This is where there is part of the spectrum in which there is no current analogue broadcasting, and preferably no planned analogue broadcasting either. Under these circumstances, the channels for digital broadcasting stations can be planned to make fully efficient use of the spectrum. The latter is not possible in the case where there is considerable reuse of the channels of the existing analogue stations, as the optimum distance spacing between a pair of analogue stations and that between the same pair of stations operating digitally may be different. This necessarily introduces some inefficiency in the use of the spectrum. On the other hand, reuse of channels makes it possible to plan for a transition from analogue to digital with a reasonable hope of controlling interference levels and the possibility for viewers and broadcasters to make use of the existing infrastructure to a large extent.
It will have been noted that in the limited discussion of the two planning scenarios above, there is an assumption that different scenarios can be adopted by different administrations and also in different parts of the planning area. The adoption of different scenarios can be considered at an even more detailed level, that is at the level of individual broadcasting stations. One example would be where an administration considers that a particular analogue station needs to be maintained in operation for a long period while some other analogue station (or stations) can be changed to digital operation in the very short term. The converse is also true. An administration can decide that for some specific reason, and there can be many such reasons, an analogue station should be changed to digital operation as early as possible while other stations can be left as analogue for a much longer time.
3.2 UMTS/GSM and DVB-T Convergence
The ad hoc group DVB-UMTS/GPRS/GSM has classified the co-operation of DVB-T and UMTS/GSM/GPRS for commercial applications in different scenarios. This classification typically uses the broadcast channel for the down-load (unidirectional way), and the telecommunication channel (PSTN, xDSL, GSM, GPRS, UMTS, and…) for the up/down-load (unidirectional/bi-directional way). Particularly are addressed the user view for services built on Telco/Broadcast convergence.
There are many scenarios that can be considered for a co-coordinated use of UMTS/GPRS/GSM and DVB networks. These range from the simple sharing of content to the sharing of spectrum. A basic assumption for a co-operation of mobile network is that terminals are able to access both networks (DVB and UMTS/GPRS/GSM). Such a co-operation of both networks will improve the capabilities and varieties of services, the economics for the user and, hopefully, the ease of handling. It combines the network service modes of both network and thus enables new solutions for applications. Of course, there will still be services, which need only one network. Some applications like interactive TV can use also separate terminals, e.g. a set top box (IRD) of a UMTS/GPRS/GSM mobile terminal. Furthermore, the co-operation of networks enables the use of the UMTS/GPRS/GSM operator’s services like customer relationship management and billing for all services.
Initially, the work of DVB-UMTS/GPRS/GSM group has focused on the provision of services using the DVB-T and UMTS/GPRS/GSM platforms. The specifications will be developed in different stages, corresponding to the availability of present hardware and software products and the development time required for new solutions mainly:
Interactive Broadcast services (video, data); use of UMTS/GPRS/GSM as a return channel for interactive TV. UMTS shall be able to substitute GSM as a return channel for these services for dial in access and further for Internet based access.
Integration at the terminal level. No definitive co-operation of networks is required. The specification covers only the terminal, which is able to switch between the two networks and related services. The user has the choice to select the service of DVB or UMTS/GPRS/GSM to get requested information.
Integration at terminal and network levels. Co-operation of networks with applications using both co-operating network resources. Terminals are firstly portable PCs, PDAs etc combined with a UMTS/GPRS/GSM “modem” for interactive services, which run on a co-operative software platform, e.g. in a domestic or car environment. The mobile handset and the broadcast receiver can connect (for example) into the PC via USB ports. The data allocation in the DVB Transport Stream can be used for IP data carousel play out and multicasting/unicasting; UMTS/GPRS/GSM will operate as an interaction channel for Internet services.
Mobile operation: full mobility and range of co-operative services within a single handset (terminal). Delivery of DVB content and services over UMTS/GPRS/GSM will be supported. Content can be delivered via IP over the DVB-T platform, in all or part of the multiplex or (suitably re-purposed) over UMTS/GPRS/GSM.
The co-operation platform will incorporate all functions that enable inter-working between legacy domains (broadcast, cellular), or new functions that are not available in any legacy domain.