Research on Retransmission and Combining Techniques in Power Line Communication Systems

Power Line Communication (PLC) utilizes the existing power line infrastructure for data transmission and offers the advantage of low deployment costs. However, the PLC channel is subject to a highly complex network topology, frequent load variations, and noise as well as impulsive interference introduced by the switching operations of various electrical devices. As a result, it exhibits pronounced frequency-selective fading and time-varying characteristics. Under such challenging channel conditions, existing PLC transmission schemes are no longer sufficient to meet increasing performance requirements. This paper introduces the Chase combining mechanism of Hybrid Automatic Repeat Request (HARQ) into the PLC physical-layer link. At the receiver, soft information from multiple transmissions is accumulated, thereby improving the transmission stability and resource utilization efficiency of PLC under complex channel environments. Simulation results show that Chase combining can significantly reduce the bit error rate in the low signal-to-noise ratio region and enhance link reliability in complex PLC noise environments. Hardware implementation results indicate that the main overhead of this mechanism is concentrated in buffering and accumulation logic, demonstrating its feasibility for Field-Programmable Gate Array (FPGA) implementation.