A.2 Performance Requirements

26.2673GPPeCall data transferGeneral descriptionIn-band modem solutionRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The following text defines point by point the (Service) Performance Requirements for an eCall candidate. They have been taken directly from 3GPP TS 22.101 [1].

NOTE 1: 3GPP TS 22.101 [1] has been modified in the meantime to version V8.8.0. The changes introduced have been evaluated. They have no influence on the selection phase for eCall.

NOTE 2: For the sake of the selection procedure, the candidate shall provide means for automatic retransmission. This is however not necessarily the final eCall Protocol.

1. The data may be sent prior to, in parallel with, or at the start of the voice component of an emergency call.

NOTE 3: In-band data can not be sent prior to the point in time when the voice channel is established end-to-end.

This requirement does not require additional interpretation.

2. Should the PSAP request additional data then this may be possible during the established emergency call.
This service requirement is considered in the selection as follows:
"The eCall candidate algorithm shall allow the PSAP to request additional data at any time during the established emergency call."

3. The realisation of the transfer of data during an emergency call shall minimise changes to the originating and transit networks.
This service requirement is considered in the selection as follows: "The introduction of the eCall data transfer feature should have minimal (ideally no) impact on any existing mobile and transit network (in Europe), i.e. it should not require (major) changes nor impose (major) restrictions to future evolutions of the networks."

4. Both the voice and data components of the emergency call shall be routed to the same PSAP or designated emergency call centre.

NOTE 4: In-band data can not be routed somewhere other than the voice channel it uses.

This service requirement does not need to be considered in the selection.

5. The transmission of the data shall be acknowledged and if necessary data shall be retransmitted.
This service requirement is considered in the selection as follows: "In the case of errors detected by the candidate algorithm in the received data, a retransmission shall be requested by the candidate algorithm."

6. A UE configured only to transfer data during emergency calls (e.g. eCall only UE) shall not generate signalling to the network besides what is needed to place an emergency call.
This service requirement does not need to be considered in the selection.

7. With the exception of the following specific requirements, considered necessary for the satisfactory operation of the eCall service, all existing TS12 emergency call requirements shall apply.
This service requirement does not need to be considered in the selection.

8. An eCall shall consist of a TS12 emergency call supplemented by a minimum set of emergency related data (MSD).
This service requirement does not need to be considered in the selection.

9. An eCall may be initiated automatically, for example due to a vehicle collision, or manually by the vehicle occupants.
This service requirement does not need to be considered in the selection.

10. The Minimum Set of Data (MSD) sent by the In vehicle System (IVS) to the network shall not exceed 140 bytes.
This service requirement is considered in the selection as follows: "The whole 140 Bytes of the MSD shall be made available to the PSAP."

11. The MSD should typically be made available to the PSAP within 4 seconds, measured from the time when end to end connection with the PSAP is established.
This service requirement is considered in the selection as follows: "In optimal conditions (error-free radio channel, GSM FR codec and FR AMR 12.2 kbit/s mode) the eCall candidate procedure shall be able to transmit the whole 140 bytes of the MSD reliably within 4 seconds, measured from the time when the transmission from the IVS to the PSAP begins (after a trigger from the PSAP has been detected)."

NOTE 5: See Performance Requirement 14.

NOTE 6: "Reliability" is defined in the new Performance Requirement 15.

NOTE 7: The Performance Objectives give additional guidelines for the performance under non-ideal channel conditions.

12. Should the MSD component not be included in an eCall, or is corrupted or lost for any reason, then this shall not affect the associated TS12 emergency call speech functionality.
This service requirement does not need to be considered in the selection.

13. A call progress indication shall be provided to the user whilst the MSD transmission is in progress
This service requirement does not need to be considered in the selection.

In addition to the above Service Requirements, the following Performance Requirement shall apply to an eCall candidate solution.

14. Installation of eCall equipment in a vehicle shall not affect an emergency call to a PSAP which is not upgraded to receive eCall data, i.e. the eCall candidate algorithm shall not send the eCall data unless the PSAP requests that it do so.

15. The MSD shall be transmitted reliably to the PSAP. An MSD transmission is considered reliably terminated, if a cyclic redundancy check (CRC) of at least 28 bits, applied to the entire MSD, detects no errors.

NOTE 8: If the CRC detects an error in the MSD, then an automatic retransmission shall be triggered, unless the PSAP decides to stop the transmission.