13.17.2 Frequency error under multipath and interference conditions

3GPP51.010-1Mobile Station (MS) conformance specificationPart 1: Conformance specificationTS

13.17.2.1 Definition

The frequency error under multipath and interference conditions is a measure of the ability of the MS to maintain frequency synchronization with the received signal under conditions of Doppler shift, multipath reception and interference.

13.17.2.2 Conformance requirement

1. The MS carrier frequency error for each burst shall be accurate to within 0,1 ppm for GSM 700, GSM 850, GSM 900, DCS 1800, PCS 1 900 and 0,2 ppm for GSM 400 compared to signals received from the BS for signal levels down to 3 dB below the reference sensitivity level.

1.1 Under normal conditions; 3GPP TS 05.10, subclauses 6 and 6.1.

1.2 Under extreme conditions; 3GPP TS 05.10, subclauses 6 and 6.1; 3GPP TS 05.05 annex D subclauses D.2.1 and D.2.2.

2. The MS carrier frequency error for each burst shall be accurate to within 0,1 ppm, for GSM 700, GSM 850, GSM 900, DCS 1800 and PCS 1 900 and 0,2 ppm for GSM 400 compared to signals received from the BS for 3 dB less carrier to interference ratio than the reference interference ratios; 3GPP TS 05.10, subclauses 6 and 6.1.

3GPP TS 45.05 subclause 2:

For T-GSM 810 the requirements for GSM 900 shall apply, apart for those parameters for which a separate requirement exists.

13.17.2.3 Test purpose

1. To verify that the MS carrier frequency error at the PDTCH input level for reference performance, under conditions of multipath and Doppler shift does not exceed 0,1 ppm for GSM 700, T-GSM 810, GSM 850, GSM 900, DCS 1 800 and PCS 1 900 and 0,2 ppm for GSM 400 + the frequency error due to the Doppler shift of the received signal and the assessment error in the MS.

1.1 Under normal conditions.

1.2 Under extreme conditions.

NOTE 1: Although the conformance requirement states that frequency synchronization should be maintained for input signals 3 dB below PDTCH input level for reference performance. Due to the Radio Link Failure counter this test condition cannot be established. Hence all tests in this subclause are conducted at PDTCH input level for reference performance.

2. To verify that the MS carrier frequency error, under interference conditions and TUlow fading profile, does not exceed 0,1 ppm for GSM 700, T-GSM 810, GSM 850, GSM 900, DCS 1 800 and PCS 1 900 and 0,2 ppm for GSM 400 + the frequency error due to the Doppler shift of the received signal and the assessment error in the MS.

NOTE 2: The test adds the effect of Doppler shift to the requirements as the conformance requirement refers to signals input to the MS receiver whereas the frequency reference for measurement will not take account of the Doppler shift.

13.17.2.4 Method of test

This test uses the same measurement process as test 13.16.1 for GMSK modulated uplink transmission and 13.17.1 for 8PSK modulated uplink transmission for the MS operating under various RF conditions.

NOTE: The BA list sent on the BCCH will indicate at least six surrounding cells with at least one near to each band edge. It is not necessary to generate any of these BCCH but if they are provided none will be within 5 channels of the ARFCN used for the serving BCCH or PDTCH.

EGPRS Switched Radio Loopback Mode (3GPP TS 04.14, subclause 5.5) shall be utilised. This is since 8PSK modulated transmission is applied in the downlink during the test and EGPRS Switched Radio Loopback Mode is the only mandatory test mode for EGPRS MS that implements different modulations between concurrent downlink and uplink transmission. This test requires such test mode capability since an EGPRS MS is also allowed to support only GMSK modulated uplink transmission.

13.17.2.4.1 Initial conditions

The test shall be run under the default EGPRS conditions defined in clause 50 on an ARFCN in the Mid range, with power control parameter ALPHA (α) set to 0. The level of the serving cell BCCH is set to 10 dB above the input signal level at reference sensitivity performance for PDTCH/MCS-5 applicable to the type of MS and the fading function set to RA. The SS waits 30 s for the MS to stabilize to these conditions. The SS commands the MS to transmit at maximum power.

13.17.2.4.2 Procedure

a) The SS transmits packets under static conditions, using MCS-5 coding. The SS is set up to capture the first burst transmitted by the MS during the uplink TBF. EGPRS Switched Radio Block Loop Back Mode is initiated by the SS according to the procedure defined in 3GPP TS 04.14; 5.5.1 on a PDTCH/MCS-5 channel in the mid ARFCN range. The PDTCH level is set to 10 dB above the input signal level at reference sensitivity performance for PDTCH/MCS-5 applicable to the type of MS and the fading function is set to RA. 8PSK modulated downlink transmission shall be utilised.

b) The SS calculates the frequency accuracy of the captured burst as described in test 13.16.1 for MS capable of only GMSK modulated transmission in the uplink. For MS capable of both GMSK and 8PSK modulated transmission in the uplink the frequency accuracy of the captured burst shall be calculated as described in the test 13.17.1.

c) The SS sets the serving cell BCCH and PDTCH to the PDTCH input signal level at reference sensitivity performance for PDTCH/MCS-5 applicable to the type of MS, still with the fading function set to RA and then waits 30 s for the MS to stabilize to these conditions.

d) The SS shall capture subsequent bursts from the traffic channel in the manner described in test 13.16.1 or test 13.17.1.

NOTE: Due to the very low signal level at the MS receiver input the MS receiver is liable to error. The "looped back" bits are therefore also liable to error, and hence the SS does not know the expected bit sequence. The SS will have to demodulate the received signal to derive (error free) the transmitter burst bit pattern. Using this bit pattern the SS can calculate the expected phase trajectory according to the definition within 3GPP TS 05.04.

e) The SS calculates the frequency accuracy of the captured burst as described in test 13.16.1 or test 13.17.1.

f) Steps d) and e) are repeated for 5 traffic channel bursts spaced over a period of not less than 20 s.

g) Both downlink and uplink TBFs are terminated. The initial conditions are established again and steps a) to f) are repeated but with the fading function set to HT200 for GSM 400, HT120 for GSM700 and HT100 for all other bands.

h) The initial conditions are established again and steps a) to f) are repeated but with the fading function set to TU100 for GSM 400, TU60 for GSM700 and TU50 for all other bands.

i) The initial conditions are established again and steps a) and b) are repeated but with the following differences:

– the levels of the BCCH and PDTCH are set to – 72,5 dBm + Corr. Corr = the correction factor for reference performance according to Spec 45.005 subclause 6.2.

– two further independent 8-PSK modulated interfering signals are sent on the same nominal carrier frequency as the BCCH and PDTCH and at a level 20,5 dB below the level of the PDTCH and modulated with random data, including the midamble.

– the fading function for all channels including the interfering signals is set to TUlow.

– the SS waits 100 s for the MS to stabilize to these conditions.

j) Repeat steps d) to f), except that at step f) the measurement period must be extended to 200 s and the number of measurements increased to 20.

k) The initial conditions are established again and steps a) to j) are repeated for ARFCN in the Low ARFCN range.

l) The initial conditions are established again and steps a) to j) are repeated for ARFCN in the High ARFCN range.

m) Repeat step h) under extreme test conditions (see annex 1, TC2.2).

13.17.2.5 Test requirements

The frequency error, with reference to the SS carrier frequency as measured in repeats of step e), for each measured burst shall be less than the values shown in table 13.17-1.

Table 13.17-1: Requirements for frequency error under multipath,
Doppler shift and interference conditions

GSM 400

T-GSM 810, GSM 850 and GSM 900

DCS 1 800 and PCS 1 900

Propagation condition

Permitted frequency error

Propagation condition

Permitted frequency error

Propagation condition

Permitted frequency error

RA500

±300 Hz

RA250

±300 Hz

RA130

±400 Hz

HT200

±180 Hz

HT100

±180 Hz

HT100

±350 Hz

TU100

±160 Hz

TU50

±160 Hz

TU50

±260 Hz

TU6

±230 Hz

TU3

±230 Hz

TU1,5

±320 Hz

GSM 700

Propagation condition

Permitted frequency error

RA 300

±300 Hz

HT 120

±180 Hz

TU 60

±160 Hz

TU 3.6

±230 Hz