5.1 General description

36.5093GPPEvolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Packet Core (EPC)Release 17Special conformance testing functions for User Equipment (UE)TS

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

The UE test loop function provides access to isolated functions of the UE via the radio interface without introducing wherever possible new physical interfaces just for the reason of conformance testing.

NOTE 0: One exception from the rule above is the UE test loop mode E and UTC time reset when used for V2X out-of-coverage test scenarios which require an additional physical interface for the transmission of AT commands. This has been based on the assumption that V2X devices will normally provide such interface for other than testing purposes e.g. for device configuration.

NOTE 1: It should be emphasised that the UE test loop function only describes the functional behaviour of the UE with respect to its external interfaces; physical implementation of the UE test loop function is completely left open to the manufacturer.

The UE test loop function is activated by transmitting the appropriate TC message to the UE, see clause 6.

The UE test loop function can be operated in different loopback modes:

– UE test loop mode A;

– UE test loop mode B;

– UE test loop mode C;

– UE test loop mode D;

– UE test loop mode E;

– UE test loop mode F;

– UE test loop mode G;

– UE test loop mode H;

– UE test loop mode I.

UE test loop mode A provides loopback of PDCP SDUs for bi-directional data radio bearers while UE is operating in E-UTRA or NB-IoT mode. The downlink PDCP SDUs received by the UE on each bi-directional data radio bearer are returned on the same radio bearer regardless of the PDCP SDU contents and of the TFT of the associated EPS bearer context [36].

UE test loop mode B provides loopback of PDCP SDUs (E-UTRA and UTRA), SNDCP PDUs (GSM/GPRS) and RLP PDUs (CDMA2000) for bi-directional EPS bearers while UE is operated in E-UTRA, NB-IoT, UTRA, GSM/GPRS or CDMA2000 modes. When operating in E-UTRA, NB-IoT, UTRA or GSM/GPRS then the downlink PDCP SDUs or SNDCP PDUs received by the UE on all bi-directional data radio bearers are returned by the UE on the data radio bearer associated with an EPS bearer context with a TFT matching the TCP/UDP/IP protocol information within the PDCP SDU or SNDCP SDU [36]. When operating in CDMA2000 modes, the downlink RLP PDUs received by the UE on all bi-directional data radio bearers are returned by the UE on the data radio bearer with the smallest identity, regardless of the RLP PDU content and of the TFT of the associated EPS bearer context.

NOTE 2: When multiple PDN connections are established (or multiple Primary PDP Contexts are active), it is assumed that different IP addresses are allocated to the UE by the SS on each PDN.

UE test loop mode C provides counting of successfully received MBMS Packets on a given MTCH while UE is operating in E-MBMS/E-UTRA mode. For E-MBMS then one or more MTCHs are multiplexed on a MCH. MBMS packets for a MTCH are delivered as one RLC SDU per MBMS packet segmented into one or more RLC UMD PDUs.

UE test loop mode D provides means for announcing or monitoring of ProSe Direct Discovery messages on SL-DCH, as specified by the test loop mode D setup IE in the CLOSE UE TEST LOOP message. In particular, for discovery monitor operation, UE test loop mode D provides counting of successfully received SL-DCH MAC SDUs while the UE is operating in ProSe Direct Discovery/E-UTRA mode. For discovery announce operation, UE test loop mode D provides trigger for transmission of ProSe Direct Discovery message on SL-DCH.

NOTE 3: UE test loop mode D is intended for RF/RRM testing purposes.

NOTE 4: ProSe Direct Discovery messages on the PC5 interface are delivered as one MAC SDU per ProSe Direct Discovery message.

UE test loop mode E provides means for either transmit or receive of ProSe Direct or V2X Communication packets, as specified by the test loop mode E setup IE in the CLOSE UE TEST LOOP message. In particular, for communication receive operation, UE test loop mode E provides counting of successfully received STCH PDCP SDUs, PSCCH PHY transport blocks and PSSCH PHY transport blocks while the UE is operating in ProSe Direct or V2X Communication/E-UTRA mode. For communication transmit operation, UE test loop mode E provides trigger for transmission of ProSe Direct or V2X Communication packets. For the V2X out-of-coverage scenarios this trigger utilises AT commands and requires an appropriate physical interface.

NOTE 5: Void

NOTE 6: The Application trigger required to force the UE to start or stop a particular ProSe Service is out of the scope of the test loop modes D and E.

UE test loop mode F provides counting of successfully received MBMS Packets on a given SC-MTCH while UE is operating in SC-PTM/E-UTRA mode. For SC-PTM one SC-MTCH is transmitted on a DL-SCH. MBMS packets for a SC-MTCH are delivered as one RLC SDU per MBMS packet segmented into one or more RLC UMD PDUs.

UE test loop mode G provides loopback of the User data container content of any received downlink ESM DATA TRANSPORT message in uplink. The received data can be configured to be either returned via the UE EMM entity (before the UE uplink rate control entity) or as a RLC SDU to the SRB RLC entity (SRB1bis for NB-IoT UE or to SRB2 for E-UTRA UE). UE test loop mode G may be configured to delay the uplink loopback of user data. UE test loop mode G may also be configured to repeat the received user data of the User data container in uplink to generate higher data rates in uplink.

UE test loop mode H provides loopback of the TP-User-Data field (including the SMS user data) of any received downlink TPDU (SMS-DELIVER) in uplink. The received data can be configured to be either returned via the UE SM-TL entity or as a RLC SDU to the SRB RLC entity (SRB1bis for NB-IoT UE or to SRB2 for E-UTRA UE). UE test loop mode H may be configured to delay the uplink loopback of SMS user data. UE test loop mode H may also be configured to repeat the received SMS user data in uplink to generate higher data rates in uplink.

NOTE 7: UE test loop mode G and H are intended for control plane data testing for UEs supporting EPS services with Control Plane CIoT EPS optimization.

NOTE 8: The delay timer for UE test loop mode G and H is triggered by the first reception of user data after the reception of a CLOSE UE TEST LOOP TC message. While the delay timer is running only the user data received in the latest ESM DATA TRANSPORT or SMS message is buffered.

NOTE 9: The repetition of uplink transmission of uplink messages carrying data can be configured as 0 (no data returned), 1 (the same content and size of user date as received in downlink is returned) or value N > 1 (user data corresponding to N times repetition of the received user data is returned in uplink).

UE test loop mode I provides loopback of the IP PDUs received in User data container content of downlink ESM DATA TRANSPORT message in uplink via the UE uplink TFT hander and the UE EMM entity (before the UE uplink rate control entity).

NOTE 10: UE test loop mode I is intended for control plane data testing for UEs supporting EPS services with Control Plane CIoT EPS optimization.

UE test loop mode A is mandatory to all E-UTRA UEs and all NB-IoT UEs supporting user plane data transfer.

UE test loop mode B for operation in E-UTRA mode is mandatory to all E-UTRA UEs and all NB-IoT UEs supporting user plane data transfer.

UE test loop mode B for operation in UTRA mode is mandatory to all E-UTRA UEs supporting UTRA radio access.

UE test loop mode B for operation in GSM/GPRS mode is mandatory to all E-UTRA UEs supporting GSM/GPRS radio access.

UE test loop mode B for operation in CDMA2000 mode is mandatory to all E-UTRA UEs supporting CDMA2000 radio access.

UE test loop mode C is mandatory for E-UTRA UEs supporting E-MBMS.

UE test loop mode D is mandatory for E-UTRA UEs supporting ProSe Direct Discovery.

UE test loop mode E is mandatory for E-UTRA UEs supporting ProSe Direct or V2X Communication.

UE test loop mode F is mandatory for E-UTRA UEs supporting SC-PTM.

UE test loop mode G is mandatory for UEs supporting Control Plane CIoT EPS optimization and control plane data transfer using the ESM DATA TRANSFER procedure.

UE test loop mode H is mandatory for UEs supporting Control Plane CIoT EPS optimization and control plane data transfer using SMS.

UE test loop mode I is mandatory for UEs supporting Control Plane CIoT EPS optimization and control plane data transfer using the ESM DATA TRANSFER procedure.

Support of UPDATE UE LOCATION INFORMATION is optional for all E-UTRA UEs with the exception of E-UTRA UEs supporting ProSe Direct Communication for which it is mandatory.

For E-UTRA UE supporting multiple radio access technologies then UE reception of Test Control messages is limited to UE operating in E-UTRA mode, while continuation of loopback of user data is provided over the change to other UE supported radio access technologies.

UE test loop mode B for operation in UTRA, GSM/GPRS and CDMA2000 mode is only applicable for loopback of user data in PS domain.

The TC entity may be seen as a L3 or a NAS entity.

Figure 5.1-1 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode A. The loopback of PDCP SDUs for UE test loop mode A is specified in sub clause 5.4.3.

Figure 5.1-2 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode B. The loopback of IP PDUs/PDCP SDUs for UE test loop mode B and UE in E-UTRA mode is specified in subclauses 5.4.4.2 and 5.4.4.3.

Figure 5.1-3 shows a functional block diagram of UE test loop function for UE test loop mode B and UE operating in UTRA mode. The loopback of IP PDUs/PDCP SDUs for UE test loop mode B and UE in UTRA mode is specified in subclauses 5.4.4.4 and 5.4.4.5.

Figure 5.1-4 shows a functional block diagram of UE test loop function for UE test loop mode B for UE operating in GSM/GPRS mode. The loopback of IP PDUs/SNDCP SDUs for UE test loop mode B and UE in GSM/GPRS mode is specified in subclauses 5.4.4.6 and 5.4.4.7.

Figure 5.1-5 shows a functional block diagram of UE test loop function for UE test loop mode B for UE operating in CDMA2000 mode. The loopback of IP PDUs/RLP SDUs for UE test loop mode B and UE in CDMA2000 mode is specified in subclauses 5.4.4.8 and 5.4.4.9.

Figure 5.1-6 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode C. The MBMS Packet Counter function for UE test loop mode C is specified in sub clause 5.4.4.a. The MBMS Packet Counter function is limited to count successfully received MBMS packets on one MTCH configured by the SS when UE test loop mode C is activated.

Figure 5.1-7 and Figure 5.1-8 show a functional block diagram of the UE test loop mode for TC entity and UE test loop mode D. The ProSe Direct Discovery Packet Counter function for UE test loop mode D is specified in clause 5.4.4b. The ProSe Direct Discovery packet counter function is limited to count successfully received SL-DCH MAC SDUs when UE test loop mode D is activated.

Figure 5.1-9 and Figure 5.1-10 show a functional block diagram of the UE test loop mode for TC entity and UE test loop mode E for UE supporting ProSe Direct, or, V2X when UE is in in-coverage state. Figure 5.1-9a and Figure 5.1-10a show a functional block diagram of the UE test loop mode for TC entity and UE test loop mode E for UE supporting V2X when UE is in out-of-coverage state; the Electrical Man Machine Interface (EMMI) required for facilitating the AT commands transmission is specified in clause 8. The ProSe Direct or V2X Communication Packet Counter function for UE test loop mode E is specified in clause 5.4.4c. The ProSe Direct or V2X Communication packet counter function is limited to count successfully received STCH PDCP SDUs, PSCCH PHY Transport blocks and PSSCH PHY Transport blocks when the UE test loop mode E is activated.

Figure 5.1-11 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode F. The SC-PTM Packet Counter function for UE test loop mode F is specified in sub clause 5.4.4.d. The SC-PTM Packet Counter function is limited to count successfully received MBMS packets on one SC-MTCH configured by the SS when UE test loop mode F is activated.

Figure 5.1-12 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode G when User data container content received in a downlink ESM DATA TRANSFER message is configured to be returned in uplink via the EMM entity. Figure 5.1-13 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode G when User data container content received in a downlink ESM DATA TRANSFER message is configured to be returned in uplink in a RLC SDU via the SRB1bis/SRB2 RLC AM entity. The UE test loop mode G mode of operation is specified in sub clause 5.4.4e.

Figure 5.1-14 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode H when TP-User-Data (SMS user data) received in a downlink TPDU (SMS-DELIVER) is configured to be returned in uplink via the SM-TL entity (in a TPDU (SMS-SUBMIT)).

Figure 5.1-15 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode H when TP-User-Data (SMS user data) received in a downlink TPDU (SMS-DELIVER) is configured to be returned in uplink in a RLC SDU via the SRB1bis/SRB2 RLC AM entity. The UE test loop mode H mode of operation is specified in sub clause 5.4.4f.

Figure 5.1-16 shows a functional block diagram of UE test loop function for TC entity and UE test loop mode I when IP PDU received in User data container content in a downlink ESM DATA TRANSFER message is returned in uplink via the EMM entity. The UE test loop mode I mode of operation is specified in sub clause 5.4.4g.

NOTE 7: ROHC functionality in PDCP Layer 2 is optional for UE implementations.

Figure 5.1-1: Model for Test Control and UE Test Loop Mode A on UE side for E-UTRA and NB-IoT

Figure 5.1-2: Model for Test Control and UE Test Loop Mode B on UE side for E-UTRA and NB-IoT

Figure 5.1-3: Model for UE Test Loop Mode B on UE side for UTRA

Figure 5.1-4: Model for UE Test Loop Mode B on UE side for GSM/GPRS

Figure 5.1-5: Model for UE Test Loop Mode B on UE side for CDMA2000

Figure 5.1-6: Model for UE test loop mode C on UE side

Figure 5.1-7: Model for UE test loop mode D on UE side
(when Discovery monitor is indicated in the UE test loop mode D setup IE)

Figure 5.1-8: Model for UE test loop mode D on UE side
(when Discovery announce is indicated in the UE test loop mode D setup IE)

Figure 5.1-9: Model for UE test loop mode E on UE side ProSe Direct, or, V2X when UE is in in-coverage state
(when Communication receive is indicated in UE test loop mode E setup IE)

Figure 5.1-9a: Model for UE test loop mode E on UE side based on AT commands V2X when UE is in out-of-coverage state
(when Communication receive is indicated in UE test loop mode E setup IE)

Figure 5.1-10: Model for UE test loop mode E on UE side ProSe Direct, or, V2X when UE is in in-coverage state
(when Communication transmit is indicated in the UE test loop mode E setup IE)

Figure 5.1-10a: Model for UE test loop mode E on UE side based on AT commands V2X when UE is in out-of-coverage state
(when Communication transmit is indicated in the UE test loop mode E setup IE)

Figure 5.1-11: Model for UE test loop mode F on UE side

Figure 5.1-12: Model for UE test loop mode G on UE side configured to return downlink User data container content received in ESM DATA TRANSFER message in uplink via the EMM entity (before the UE uplink rate control entity)

Figure 5.1-13: Model for UE test loop mode G on UE side configured to return downlink User data container content received in ESM DATA TRANSFER message in uplink via the SRB1bis/SRB2 RLC AM entity

Figure 5.1-14: Model for UE test loop mode H on UE side configured to return the SMS user data received in the TPDU (SMS-DELIVER) received in the downlink RP-DATA message in uplink via the SM-TL entity

Figure 5.1-15: Model for UE test loop mode H on UE side configured to return the SMS user data received in the TPDU (SMS-DELIVER) received in the downlink RP-DATA message in uplink via the SRB1bis/SRB2 RLC AM entity

Figure 5.1-16: Model for UE test loop mode I on UE side configured to return downlink IP PDUs received in a ESM DATA TRANSFER message in uplink via the UE UL TFT handler to the EMM entity (before the UE uplink rate control entity)