Channel Adaptation based on Cyclo-Stationary Noise Characteristics in PLC Systems

As power line communication (PLC) systems become more pervasive, there is increasing demand for new generations of PLC systems that enable bandwidth intensive applications like audio/video streaming and broadband access. To achieve the data rates necessary to support such applications within the current regulatory constraints, PLC systems should exploit the inherent characteristics of the power line channel that enable a more aggressive and optimized channel adaptation. One such characteristic is the cyclic variation of the noise power with the phase of the underlying AC line cycle. In this paper, we use extensive channel characterization measurements and analysis to investigate the performance enhancements that can be achieved by using a channel adaptation mechanism that exploits the cyclic variation in power line noise characteristics. The results show that a 30% improvement in physical layer (PHY) data rates can be obtained by continuously adapting to, and synchronizing communications with, the AC line cycle. Since continuous adaptation with respect to time is unduly complex for practical systems, we propose dividing the AC line cycle into multiple regions and adapting independently in each region. Results show that using a region size of 1-2 milliseconds provides optimal MAC throughput on most paths tested