scope:

Introduction

Certain extensions of the display capabilities of existing teletext and subtitling services (e.g. the inclusion of non-alphabetic writing systems [CCIR, 1986-90a] as well as new data services, some of which are already identified in CCIR Report 802, require the adoption of error-protection strategies able to guarantee a high degree of confidence in the recovered message without undue repetition.

Sophisticated and powerful decoding strategies are now feasible thanks to progress in consumer microelectronic technology and can be implemented today, at low cost in commercial receivers. Thus, additions of a means of forward error correction will allow data to be corrected before they are decoded when the data packets are organized as a error correcting code [CCIR, 1982-86a]. Provided adequate buffer storage exists and time between data acquisitions permits sophisticated software programming techniques for error correction can also be used to acquire the service components correctly [CCIR, 1986-90b].

Section 2 outline the general considerations for error protection strategies. Section 3 reports some studies of error protection strategies applied to present terrestrial broadcasting systems. Section 4 reports examples of error protection strategies for data transmission using satellite broadcast channels.