To develop a digital network for television terrestrial broadcasting and contribute to a European standard that:
- Uses the traditional UHF/VHF frequency bands.
- Does not degrade quality of existing analogue services.
- Provides HD capability for fixed receivers.
- Has High Definition services capacity for fixed receivers and portable/mobile reception with significant coverage in clear channels.
- Allows simpler and economic frequency management.
- Can be demonstrated easily with available technology and be implementable at consumer prices by 1997/1998.
- Works with cable distribution and contribution nets.
- Gives rise to a wide European consensus in order to bring unified European views in ITU-R discussions.
The main objective of the research was to develop a digital communications network suited to television terrestrial (wireless) broadcasting that:
can be used within the traditional frequency plan of ultrahigh frequency (UHF) and very high frequency (VHF) bands;
provides high definition (HD) capability for fixed receivers;
provides the capability of portable (plug free) reception as well as mobile reception;
allows further simplification and economy in frequency management, by use of single frequency network concept, locally, regionally or nationwide;
can be demonstrated easily with current technology and be proven to be implementable at consumer prices in 1998 technology;
gives rise to a wide European consensus in order to bring unified European views on Comite Consultatif International des Radiocommunications (CCIR) discussions.
Key issues in the research include:
characterization of UHF and VHF channels in the simulcast environment as well as in a clear channel configuration;
selection of bandwidth and power efficient modulation and channel coding schemes;
measurement of performance and evaluation of receiver cost and its compatibility with cable distribution (community antennae);
selection of an access control system and multiplex structure.
The research has resulted in:
a preliminary introduction strategy;
a review of carrier systems;
pilot reception quality tests performed in a simulcast environment;
live demonstation at the Montreux symposium'95, including integrated satellite and terrestrial digital television transmission, in common with the HD-SAT project;
draft specifications describing a baseline transmission system for digital terrestrial television broadcasting, inpublic enquiery phase in ETSI, expected to be adopted by the end of 1996.
dTTb realizes a series of field trials using the demonstrator built in year 3 to assess performances required, principally in single frequency networks. The specifications put forth by the project in cooperation with HD-DIVINE (Scandinavia) and HDTVT (Germany) allow realization of a second demonstrator conforming to European DVB specifications. Results of the first trials are important inputs to the final design of this demonstrator. However, this latter will not be assessed in this project.
Cost estimates of the various modules, based on the second demonstrator's design allow for the structure definition of the consumer set top adapter which will help manufacturers in the design of integrated circuits for the demodulator.
A public demonstration, held jointly with HD-SAT (R2075) will demonstrate the main concepts of terrestrial digital broadcasting at Montreux '95, in a configuration probably close to the final version but including some options (e.g. hierarchy) not likely to be kept in the baseline service.
- Characterisation of UHF/VHF channels.
- Bandwidth/power efficient modulation and channel coding
- Performance and receiver cost; compatibility with cable distribution (community antennae).
- Multiplex structure compatible with MPEG-2.
- Compatibility with other (cable) networks.
- Proposals for dTTb standards in DVB, EBU and CCIR
- Technical and economic feasibility of a digital terrestrial television service
- Introduction of experimental digital terrestrial services in Europe
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