7.2 Erroneous Frame Indication Performance

3GPP51.021Base Station System (BSS) equipment specificationRadio aspectsRelease 17TS

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

7.2.1 Test Purpose

In 3GPP TS 45.005 a Cyclic Redundancy Check (CRC) is defined for detection of erroneous Layer 2 frames or speech frames. For speech channels also additional error detecting capabilities using some soft information are needed due to DTX operation when no useful signal is transmitted to the receiver. This test verifies the reliability of the overall Bad Frame Indication (BFI) presented to the speech decoder and the Frame Erasure Indication (FEI) used on control channels.

7.2.2 Test Case

1) A test signal consisting of continuous GSM modulation of a pseudo random bit stream without mid‑amble, and at a level specified in table 7.2-1, shall be applied to the receiver antenna connector, on the same frequency as the TRX under test.

One TRX shall be configured to support a BCCH and EC-BCCH, if supported. The detection by the BSS of error‑free RACH bursts (FEI=0) shall be monitored by the BSSTE. If both GPRS is supported by the BSS and a PBCCH can be configured, then the detection by the BSS of error-free PRACH bursts (FEI=0) shall be monitored by the BSSTE. In case EC operation is supported by the BSS, the detection by the BSS of error-free EC-RACH bursts (FEI=0) shall be monitored by the BSSTE. If both the 1 TS and 2 TS EC-RACH options are supported for CC2 to CC4, both configurations shall be tested.

Table 7.2-1: Test Signal input level for testing of Erroneous Frame Indication performance

BTS Type	Test signal Input Level
GSM 400/GSM 850/GSM 900/ER-GSM 900/DCS 1800/PCS 1900/MXM 850/MXM 1900/GSM 700 normal BTS	‑84 dBm
GSM 900/ER-GSM 900/GSM 850/MXM 850/GSM 700 micro‑BTS M1	‑77 dBm
GSM 900/ER-GSM 900/GSM 850/MXM 850/GSM 700 micro‑BTS M2	‑72 dBm
GSM 900/ER-GSM 900/GSM 850/MXM 850/GSM 700 micro‑BTS M3	‑67 dBm
GSM 900/ER-GSM 900/GSM850/MXM 850/GSM 700 pico‑BTS P1	-68 dBm
DCS 1800/PCS 1900/ MXM 1900 micro‑BTS M1	‑82 dBm
DCS 1800/PCS 1900/ MXM 1900 micro‑BTS M2	‑77 dBm
DCS 1800/PCS 1900/ MXM 1900 micro‑BTS M3	‑72 dBm
DCS 1800/PCS 1900/ MXM 1900 pico-BTS P1	-75 dBm
GSM 400/GSM 850/GSM 900/DCS 1800/PCS 1900/GSM 700 Wide Area multicarrier BTS	-84 dBm
GSM 400/GSM 850/GSM 900/DCS 1800/PCS 1900/GSM 700 Medium Range multicarrier BTS	-78 dBm
GSM 400/GSM 850/GSM 900/DCS 1800/PCS 1900/ GSM 700 Local Area multicarrier BTS	-70 dBm

2) Step 1 shall be repeated without any RF input on the TRX under test, with the receiver antenna connector terminated with 50W.

3) Step 1 shall be repeated with one timeslot on one TRX configured for TCH/FS, TCH/HS, TCH/EFS, TCH/AxS and for FACCH. The Bad Frame Indication (BFI) shall be monitored by the BSSTE.

4) Step 3 shall be repeated without any RF input on the TRX under test, with the receiver antenna connector terminated with 50W.

5) The test shall be repeated with one timeslot on one TRX configured for TCH/FS, TCH/HS, TCH/EFS and TCH/AxS, when DTX is activated with SID frames and SACCH frames received at a level specified in table 7.2‑1 and with no transmission at the other bursts of the TCH. The Bad Frame Indication (BFI) shall be monitored by the BSSTE.

7.2.3 Void

7.2.4 Conformance requirement

Test Environment:

Normal.

Minimum requirement

In steps 1 and 2, less than 0.02 % of the frames shall be detected as error free (FEI=0). The limit applies for RACH or, if supported, for EC-RACH, separately.

In steps 3, 4 and 5, less than 1 undetected bad speech frame (i.e. detected as BFI=0) shall occur on average in a period of 60 s.

7.2.5 Requirement reference

3GPP TS 45.005 subclause 6.4.