Analysis of Medium Access Protocols for Power Line Communication Realizing In-Car Networks

The number of electronic control units in today´s vehicles is permanently increasing. The complexity of the in-car communication also increases because of the growing demand for information exchange. In the past decades rising demands have been countered with adding bus-segments. In order to reduce the complexity and the costs for the future in-car communication infrastructure, power line communication (PLC) provides an alternative. In this paper, we focus on PLC which can reduce the cabling to a minimum. After summarizing the requirements for future in-car systems, the HomePlug Green PHY standard, originally designed for Smart Grid applications, is analyzed according to its applicability to the in-car communication. Due to the availability of standard components, also cost reasons motivate the use of the HomePlug Green PHY standard. To cope with the small message size of in-car communication, we propose a concept for data transfer inside the Frame Control to reduce protocol overhead. In addition to CSMA/CA based medium access, we evaluate and compare two further collision-free variants requiring only slight protocol modifications. As one evaluation result, a priority-based access scheme shows the most promising results.