4 General
25.1733GPPRelease 17Requirements for support of Assisted Galileo and Additional Navigation Satellite Systems (A-GANSS) Time Division Duplex (TDD)TS
4.1 Introduction
The present document defines the minimum performance requirements for both UE‑based and UE‑assisted TDD A‑GANSS terminals. The minimum performance requirements also include combinations of A-GPS and A-GANSS.
4.2 Measurement parameters
4.2.1 UE‑based A-GANSS measurement parameters
In case of UE-based A-GANSS, the measurement parameters are contained in the RRC UE POSITIONING POSITION ESTIMATE INFO IE. The measurement parameter in case of UE-based A-GANSS is the horizontal position estimate reported by the UE and expressed in latitude/longitude.
4.2.2 UE‑assisted A-GANSS measurement parameters
In case of UE-assisted A-GANSS, the measurement parameters are contained in the RRC UE POSITIONING GANSS MEASURED RESULTS IE. The measurement parameters in case of UE-assisted A-GANSS are the UE GANSS code measurements, as specified in 3GPP TS 25.225 [18]. The UE GANSS code measurements that may be combined with UE GPS code phase measurements as specified in 3GPP TS 25.225 [18] are converted into a horizontal position estimate using the procedure detailed in Annex F.
4.3 Response time
Max Response Time is defined as the time starting from the moment that the UE has received the final RRC measurement control message containing reporting criteria different from "No Reporting" sent before the UE sends the measurement report containing the position estimate or the GANSS and GPS measured result, and ending when the UE starts sending the measurement report containing the position estimate or the GPS and GANSS measured result on the Uu interface. The response times specified for all test cases are Time-to-First-Fix (TTFF) unless otherwise stated, i.e. the UE shall not re‑use any information on GANSS and GPS time, location or other aiding data that was previously acquired or calculated and stored internally in the UE. A dedicated test message ‘RESET UE POSITIONING STORED INFORMATION’ has been defined in TS 34.109 [13] clause 5.4 for the purpose of deleting this information and is detailed in subclause B.1.10.
4.4 Time assistance
Time assistance is the provision of GANSS reference time to the UE from the network via RRC messages. Currently two different GANSS time assistance methods can be provided by the network.
a) Coarse time assistance is always provided by the network and provides current GANSS time to the UE. The time provided is within 2 seconds of GANSS system time. It is signalled to the UE by means of the GANSS Day and GANSS TOD fields in the GANSS Reference Time assistance data IE.
b) Fine time assistance is optionally provided by the network and adds the provision to the UE of the relationship between the GANSS system time and the current UTRAN time. The accuracy of this relationship is 10 s of the actual relationship. This addresses the case when the network can provide an improved GANSS time accuracy. It is signalled to the UE by means of the SFN and UTRAN GANSS timing of cell frames fields in the GANSS Reference Time assistance data IE.
The specific GANSS system time is identified through the GANSS Time ID field of the GANSS Reference Time IE. In case where several GANSS are used in the tests, only one GANSS Time ID is used to determine the Time of Day. For all the constellations, the GANSS Time Model assistance and UTC Model assistance shall be available at the system simulator, as specified in Annex E.
The time of applicability of time assistance is the beginning of the System Frame of the message containing the GANSS Reference time.
4.4.1 Use of fine time assistance
The use of fine time assistance to improve the GANSS performance of the UE is optional for the UE, even when fine time assistance is signalled by the network. Thus, there are a set minimum performance requirements defined for all UEs and additional minimum performance requirements that are valid for fine time assistance capable UEs only. These requirements are specified in subclause 5.1.2.
4.5 RRC states
The minimum A-GANSS performance requirements are specified in clause 5 for different RRC states that include Cell_DCH and Cell_FACH. Cell_PCH and URA_PCH states are for further study. The test and verification procedures are separately defined in Annex B.
4.6 2D position error
The 2D position error is defined by the horizontal difference in meters between the ellipsoid point reported or calculated from the UE Measurement Report and the actual position of the UE in the test case considered.
4.7 User equipment supporting multiple constellations
Minimum performance requirements are defined for each global GANSS constellation (Galileo, Modernized GPS, GLONASS and BDS). UEs supporting multiple global constellations shall meet the minimum performance requirements for a combined scenario where each UE supported constellation is simulated.
NOTE: For test cases where signals from "GPS" and "Modernized GPS" are included, "GPS" and "Modernized GPS" are considered as a single constellation, unless otherwise specified.
4.8 User equipment supporting multiple signals
For UEs supporting multiple signals, different minimum performance requirements may be associated with different signals. The satellite simulator shall generate all signals supported by the UE. Signals not supported by the UE do not need to be simulated. The relative power levels of each signal type for each GNSS are defined in Table 4.8-1. The individual test scenarios in clause 5 define the reference signal power level for each satellite. The power level of each simulated satellite signal type shall be set to the reference signal power level defined in each test scenario in clause 5 plus the relative power level defined in Table 4.8-1.
Table 4.8-1: Relative signal power levels for each signal type for each GNSS
|
|
Galileo |
GPS/Modernized GPS |
GLONASS |
QZSS |
SBAS |
BDS |
|||||||
|
Signal power levels relative to reference power levels |
E1 |
0 dB |
L1 C/A |
0 dB |
G1 |
0 dB |
L1 C/A |
0 dB |
L1 |
0 dB |
B1I |
D1 |
0 dB |
|
D2 |
+5 dB |
||||||||||||
|
E6 |
+2 dB |
L1C |
+1.5 dB |
G2 |
-6 dB |
L1C |
+1.5 dB |
||||||
|
E5 |
+2 dB |
L2C |
-1.5 dB |
L2C |
-1.5 dB |
||||||||
|
L5 |
+3.6 dB |
L5 |
+3.6 dB |
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NOTE 1: For test cases which involve "Modernized GPS", the satellite simulator shall also generate the GPS L1 C/A signal if the UE supports "GPS" in addition to "Modernized GPS".
NOTE 2: The signal power levels in the Test Parameter Tables represent the total signal power of the satellite per channel not e.g. pilot and data channels separately.
NOTE 3: For test cases which involve "BDS", D1 represents MEO/IGSO satellites B1I signal type and D2 represents GEO satellites B1I signal type.