eCall data transfer; In-band modem solution; Characterization report
The present document characterizes the performance of the eCall In-band Modem, which is used for reliable transmission of the eCall Minimum Set of Data (MSD) from an In-Vehicle System (IVS) to the Public Safety Answering Point (PSAP) via the voice channel of cellular and PSTN networks.
The European Union eCall requirements, recommendations and guidelines were developed by eSafety Forum [3] and [4], with important additional work produced by ETSI MSG, GSME, 3GPP, and CEN.
Previous work in 3GPP TR 22.967 [5] "Transfer of Emergency Call Data", examined the issues associated with the transmission of emergency call data from a vehicle to a PSAP. This analysis identified that the preferred option be based on an in-band modem solution.
eCall provides reliable full-duplex data communications between IVS and PSAP in addition to emergency voice call (E112) via the cellular network, and can be initiated either automatically or manually [6]. The eCall In-band Modem uses the same voice channel as used for the emergency voice call. eCall allows reliable transmission of MSD alternating with a speech conversation through the existing voice communication paths in cellular mobile phone systems. The expected benefit is that emergency services will be made aware of accidents much more rapidly, will get precise information on location, vehicle type etc. and therefore will be able to reach accident victims faster, with the potential to save many lives annually.
The eCall in-band modems (IVS and PSAP) are fully specified by the 'General description ' TS 26.267 [9] together with the C-code reference as provided in 3GPP TS 26.268 [7]. 3GPP TS 26.269 [8] deals with the conformance testing for eCall modem implementations.
The present document provides a detailed performance characterization of the eCall in-band modem solution. Results from the 3GPP selection tests as well as verification and characterization tests have been collected into this report. It is impossible to test the eCall modem for all conditions that might arise on the transmission path from the IVS to the PSAP. However, the selected set of test scenarios represents a wide range of conditions that are foreseen to potentially occur in the in-band transmission of eCall data over the radio access and core networks as well as the PSTN.