Comparison between interleaving and multiple DMT symbols per RS codeword in ADSL systems

This paper considers the impact of interleaving and combining multiple DMT symbols in a single RS codeword on the performance of Asymmetrical Digital Subscriber Lines (ADSL) in the presence of impulse noise. In recent years there has been an increasing interest in xDSL technology due to its high data rate capability and relative ease of deployment. Impulse noise is one of the main impairments for xDSL systems and different framing techniques are aimed at mitigating the impact of impulse noise. In the ADSL standard techniques for interleaving and combining of several consecutive symbols into a single FEC codeword are used. This paper considers the performance of the above techniques at higher layers of the protocol stack. The results are based on simulations of a generic ADSL system with a new broadband-oriented impulse noise model. The conclusions include a comparison between the packet error rates of the two techniques at different bit rates and the interaction between them when used together. The aim of this research is to find a suitable set of framing parameters and help designers in their choice of single or dual latency ADSL systems.