AL-FEC for Improved Mobile Reception of MPEG-2 DVB-T Transport Streams

الملخص EN

We investigate the use of application layer FEC protection in DVB-T (Digital Video Broadcasting-Terrestrial) networks for the provision of mobile services.

Mobile reception is characterized by variations of the received signal caused by fast fading and shadowing.

DVB-T was originally designed for fixed and portable reception, and generally does not provide enough quality in mobile environments.

The link layer protection mechanism MPE-FEC (Multi Protocol Encapsulation-Forward Error Correction) was standardized in DVB-H (Digital Video Broadcasting-Handheld) for the protection of mobile TV services.

Although DVB-T itself does not incorporate any link or application layer protection mechanism, AL-FEC (Application layer Forward Error Correction) protection can be introduced in DVB-T in a backwards compatible way.

By means of AL-FEC, it is possible to improve the robustness of DVB-T services for the provision of mobile TV.

In this paper, we explain the concept of AL-FEC protection in DVB-T and evaluate its performance by means of laboratory measurements and dynamic simulations with shadowing.

We study different configurations of AL-FEC and compare its performance with MPE-FEC.

In this paper, we discuss some implementation aspects of AL-FEC in real scenarios and propose an implementation based on Raptor codes and hash sequences.

We also present results obtained by a first AL-FEC prototype for DVB-T that demonstrates the feasibility of the approach.