Performance comparison of encoding schemes for ETSI ITS C2X communication systems

Wireless Car-to-X communication is about to enter the mass market in upcoming years. Thereby, available bandwidth is small with only a low number of usable channels and many communicating entities. Therefore, efficient data encoding schemes are required to allow bandwidth saving use of the wireless channel by embedded devices. No detailed analysis of different encoding schemes for Car-to-X communication regarding important properties like runtime, memory consumption and encoded output length has been published so far. We provide such analysis for standardized ASN.1 and binary representations as well as Google Protocol Buffers as an alternative approach to the data encoding problem. Standardised data content for CAM, DENM and the security envelope are used in the conducted performance study. We show that ASN.1 encoding outperforms usage of Google Protocol Buffers, but is outperformed by a binary encoding scheme in most cases. This implies that standardization efforts for the security envelope should reconsider the recent shift from binary encoding towards usage of ASN.1.