Sensors networks in general pose considerable technical problems in terms of data processing, communication, and sensor management. Because of potentially harsh, uncertain, and dynamic environments, along with energy and bandwidth constraints, sensor network applications will likely encounter many challenges.
To address these issues, we describe how to use Powerline Communication (PLC) based on the existing power line infrastructure in a home, office or other building, both indoor and outdoor, for networking and communication and thereby eliminating the expense and inconvenience of antenna-based networks.
It makes use of the Cypress CY8CPLC20 . It is an integrated PLC chip with the Powerline Modem PHY and Network Protocol Stack running on the same device to allow integration of multiple system functions in a single device, thereby reducing Bill of Materials (BoM) costs and providing a smarter way to implement command and control. PLC nodes inherently require some form of coupling to prevent the input circuits from being destroyed by the high voltage powerlines and also to transfer the maximum possible energy between the low voltage network and the modem.
More info here.