Modeling Effects of Impulse Noise on Application-Layer FEC in DSL Channels

Internet Protocol Television (IPTV) services rely on the existing IP network infrastructure to deliver high quality video. In order to achieve reliable services, the nature of the underlying transmission channel has to be taken into account. Erasures on access networks such as present in Digital Subscriber Lines (DSL) have to be overcome. Impulse noise, e. g. Repetitive Electrical Impulse Noise (REIN), is one of the dominant error sources in the signal band of DSL channels and can be characterized as fixed-length error bursts. One countermeasure in IPTV system design to increase the robustness against impulse noise impairments is the implementation of Forward Error Correction on the Application-Layer (AL-FEC). In this paper a mathematical model is derived which describes the effect of the REIN channel on the performance of AL-FEC schemes. The effects on the application layer are modeled by a Markov chain with a memory proportional to the error burst length. Extensive empirical simulation campaigns, in the context of AL-FEC protected IPTV services, are used to prove the correctness of the proposed model and additionally, the runtime behavior of the model is analyzed.