Experiments on timing aspects of DC-Powerline communications Pedro Silva DETI Universidade de Aveiro 3180-193 Aveiro, PORTUGAL psns@ua.pt Luis Almeida IEETA / DEEC-FEUP Universidade do Porto 4200-465 Porto, PORTUGAL lda@fe.up.pt Daniele Caprini University of Pavia via Ferrata, 1 27100, Pavia - ITALY daniele.caprini@gmail.com Tullio Facchinetti University of Pavia via Ferrata, 1 27100, Pavia - ITALY tullio.facchinetti@unipv.it Francesco Benzi University of Pavia via Ferrata, 1 27100, Pavia - ITALY francesco.benzi@unipv.it Thomas Nolte MRTC/M¨ alardalen University PO Box 883 721 23 V¨ aster˚ as, SWEDEN thomas.nolte@mdh.se Abstract The Power Line technology has received an increas- ing attention in the last decades due to its inherent ben- efits, mainly related to the reduction of cabling and as- sociated costs. Power Line Communication (PLC) was first employed in power utilities, and since the 80s in home automation, too. However, its use in the automo- tive field received relatively little attention. This paper extends previous works towards assessing PLC technol- ogy for communications within the automotive domain. In particular, it focuses on the real-time behavior of such technology, namely the DCB500 adaptors supplied by the Yamar company, showing experimental results of trans- mission delays, communication overheads and effective- ness of the medium access control policies. 1 Introduction Power Line Communication (PLC) aims at exploiting the power supply line to send/receive information without using separate dedicated wires. PLC is currently adopted in many application domains, like power utilities to inter- connect and control remote units, automatic remote meter reading, and home and building automation [6]. In these applications the power carrier is AC 50/60Hz at medium voltage or low voltage. Conversely, in specific cases, such as the automotive domain, the power line op- erates at lower DC voltage complying with batteries and electronic devices (e.g., 12 and 42 V), which implies a different coupling technology. COTS components for PLC with low voltage DC car- rier are still scarse. One such technology is the one de- veloped by the Yamar company [3] providing solutions for low bit-rates (10kbit/s-50kbit/s) similar to the LIN protocol, and medium bit-rates (125kbit/s-1Mbit/s) sim- ilar to CAN. However, this technology is relatively re- cent and there is a lack of publicly available results con- cerning two fundamental issues, EMI-related aspects and temporal-related aspects. Contributing to an independent assessment of this technology constitutes our motivation and establishes the scope of this work. In previous work [8] we have proposed a set of guide- lines to evaluate PLC technology, in general, for use in the automotive domain, and later we presented prelimi- nary results concerning EMI emission and susceptibility [9]. In this work we address the temporal behavior of this technology. In particular we use the DCB500 adap- tors that support transmission speeds of up to 500kbit/s and include several communication modes. In this paper we briefly discuss the related work in Section 2 and give an overview of the DCB500 technol- ogy from Yamar in Section 3. Then, Section 4 addresses the transmission latency and communication overheads of this technology while Section 5 presents experimen- tal results concerning its arbitration mechanism for asyn- chronous access. Section 6 concludes the paper. 2 Related work The work in [1] discusses several issues that should be addressed when looking at a potential automotive ap- plication for the PLC technology, such as providing ade- quate bandwidth, responsiveness, tolerance to EMI, etc. This latter aspect has been addressed in detail in [2], where a characterization of noise and interference over a PLC channel in the automotive environment is shown. This represents a fundamental starting point for engineer- ing a complete PLC solution that would achieve the inter- operability with solutions already in use. In fact, in [4], a PLC solution is proposed for adding redundancy to the CAN bus and thus to provide a higher overall reliability. In [7], the authors investigate an architecture to seam- lessly integrate PLC and CAN. The board is based on the DSP/FPGA technology and is suitable for automotive ap- plications. However, it allows a network speed of up to 50 kbps. Such a speed is comparable with LIN, but can- not compete with CAN. Recently, some commercial solutions appeared for building an automotive communication infrastructure. For example, devices from Yamar [3] provide speeds up 978-1-4244-2728-4/09/$25.00 ©2009 IEEE