Unequal error protection in rate adaptive spectrum management for digital subscriber line systems

Crosstalk between different lines in a cable bundle is the major source of performance degradation in DSL systems. Spectrum coordination techniques have been shown to substantially alleviate the crosstalk problem. The equal level of error protection that these techniques provide can however be excessive for some applications. Many applications with diverse error protection requirements can be sharing the same connection. In this paper, two novel rate adaptive spectrum management algorithms are presented that enable a different level of error protection for different applications. The algorithms are generalizations of the globally optimal OSB and the locally optimal DSB algorithms for systems that incorporate unequal error protection. Through simulation, it is shown that unequal error protection can lead to significant performance gains.