10 Modulation accuracy at 8-PSK, QPSK, 16‑QAM, 32-QAM or AQPSK modulation
3GPP51.026Base Station System (BSS) equipment specificationPart 4: RepeatersRelease 17TS
10.1 Test purpose
This clause applies only to repeater systems supporting 8-PSK, QPSK, 16-QAM, 32-QAM or AQPSK modulation and describes the test of the modulation accuracy.
10.2 Test case
The repeater system shall be levelled according to the recommendations of the manufacturer. For the purpose of the frequency synchronisation of the repeater system it might be necessary to connect the system to a BTS or equivalent test equipment like a mobile tester. In all cases an accurate frequency synchronisation source has to be used to synchronise the measurement setup.
For the measurement of the modulation accuracy a continuous and synchronised 8-PSK, QPSK, 16-QAM, 32-QAM or AQPSK signal modulated with a pseudo random bit sequence shall be fed successively at one frequency of the relevant MS or BTS transmit frequency band into the relevant input port of the repeater. For the AQPSK modulation the SCPIR_DL is set at 0dB. The power level of the RF input signal shall be at least 5 dB below the power level which would produce, when applied within the pass band, maximum rated output power, as declared by the manufacturer. This is to ensure that the equipment is operating in the linear output range.
The EVM shall be measured at the equivalent output of the repeater system and the calculation of the EVM shall be performed according to 3GPP TS 51.021 [10].
Test environment: Normal
Extreme temperature
10.3 Conformance requirement
For a repeater as defined in the first column of the table below the RMS EVM shall not exceed:
|
Normal symbol rate |
Higher symbol rate |
|||||||
|
AQPSK (1) |
8-PSK |
16-QAM |
32-QAM |
QPSK |
16-QAM |
32-QAM |
||
|
For a single repeater with no shift in frequency from input to output |
under normal conditions |
4,0% |
8,0 % |
4,0 % |
4,0 % |
8,0 % |
4,0 % |
4,0 % |
|
For a single repeater with no shift in frequency from input to output |
under extreme conditions |
5,0% |
8,0 % |
5,0 % |
5,0 % |
8,0 % |
5,0 % |
5,0 % |
|
For a complete repeater system using frequency shift |
under normal conditions |
6,0% |
11 % |
6,0 % |
6,0 % |
11 % |
6,0 % |
6,0 % |
|
For a complete repeater system using frequency shift |
under extreme conditions |
7,0% |
11 % |
7,0 % |
7,0 % |
11 % |
7,0 % |
7,0 % |
|
NOTE 1: Only for downlink |
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10.4 Reference requirement
3GPP TS 45.005 [13], annex E.
Annex A (informative):
Testing of gain for part band repeaters