Towards Bidirectional Power Line Communication with Digital Load-Side Transmission

The unidirectional power line communication technology 'Digital Load-Side Transmission' (DLT), which is typically used for controlling light sources in homes or small offices, has evolved into an official IEC standard [1]. However, the DLT methodology lacks a return channel enabling bidirectional communication. This paper presents a method to overcome the described limitation, proposing a system concept of receiver and transmitter for backward modulation in DLT systems that complies with the existing standard for DLT forward transmission [1]. The developed architectures of receiver and transmitter have been implemented and tested in a hardware realization using the results of [2]-[4]. Measurement results prove the feasibility of the derived bidirectional DLT system concept while the additional power consumed for backward transmission is kept within reasonable limits. Robustness of the proposed system is verified by recording the averaged 'telegram error rate' (TER) for both, forward and backward transmission, when the system is connected to 230VRMS, 50 Hz mains.