Performance of eCall Modem with Turbo Codes in AWGN and AMR

One benefit of data communication over the voice channel of the cellular network is to reliably transmit real-time high priority data in case of life critical situations. An important implementation of this use-case is the pan-European eCall automotive standard, which is scheduled for deployment in 2018. The eCall in-band modem transmits emergency information from the in-vehicle system (IVS) over the global system for mobile communication (GSM) voice channel to the public safety answering point (PSAP) in case of a collision. The GSM voice channel is characterized by the non-linear vocoder which is designed to compress speech waveforms. The in-band modem encodes the emergency data using Turbo codes and then modulates the data into waveforms to securely and reliably transmit the information over the GSM vocoder. Thus, this paper evaluates the performance of the eCall in-band modem by simulating the coded bit error rate (BER) through the additive white Gaussian noise (AWGN) and the GSM adaptive multi-rate (AMR) vocoder using Turbo codes. Performance results are presented using different AMR bit rates.