On power-efficient usage of line drivers in copper-based access networks

Recently, it has been shown that spectral optimization in copper access networks can significantly reduce the transmit power required, resulting in significant reductions in the line driver energy consumption. Building on these results, we develop an improved model for line driver power usage which focuses on the aggregate transmit power, the supply voltage, and on constraints that connect these two. We show that an ideally tuned supply voltage can save significant power relative to a fixed supply voltage. Much of these gains may be achievable with a small set of discrete supply voltage options. The line driver model is simple enough to incorporate into a full spectral optimization framework, in which line driver power usage and rate are traded-off in a utility-based optimization framework. Benefits of power supply tuning in combination with spectral optimization are illustrated in numerical examples.