7.8 AM suppression
3GPP51.021Base Station System (BSS) equipment specificationRadio aspectsRelease 17TS
7.8.1 Test Purpose
AM suppression is a measure of the ability of a BSS receiver to receive a wanted GSM modulated signal without exceeding a given degradation due to the presence of an unwanted modulated signal.
7.8.2 Test Case
If Slow Frequency Hopping (SFH) is supported by the BSS, it shall be disabled during this measurement. The measurement is performed only under static conditions.
a) In case of BTS without multicarrier receiver
This test shall be performed at any one ARFCN on one TRX and on supported channels in table 7.8-1.
b) In case of multicarrier BTS equipped with multicarrier receiver
In case of the Wide Area and Medium Range classes, the BTS shall be configured according to subclause 4.10.10 with the maximum supported number of wanted input signals or four, whichever less, applied for supported channels at a signal level as specified in table 7.8-1 at the receiver input.
In case of the Local Area class, the BTS shall be configured according to subclause 4.10.10 with the maximum supported number of wanted input signals or two, whichever less, applied for supported channels at a signal level as specified in table 7.8-1 at the receiver input.
The frequencies of the wanted signals are allocated within the maximum Base Station RF bandwidth as symmetrically located as possible around center frequency of the maximum Base Station RF bandwidth with two wanted signals at frequencies 6.0 MHz from the interfering signal, and the remaing wanted signals located at the edges of the maximum supported RF bandwidth, as long as the frequency separation in the respective frequency pairs is at least 600 kHz, as indicated in figure 7.8-1.
Figure 7.8-1 Allocation of wanted signals and interferer
If the maximum Base Station RF bandwidth does not allow allocating the signals at 6 MHz and more on each side of the interferer according to the description above, the frequency of the interferer is allocated to keep frequency separation to the wanted signals on one side of the interferer fixed at ≥ 6 MHz as described above and the wanted signal(s) are still allocated at the edge of the maximum Base Station RF bandwidth with 600 kHz frequency separation within the respective frequency pairs, if applicable.
NOTE: If the maximum number of supported wanted signals is three, above description implies that the outer signal with the smallest frequency separation to the interferer is left out compared to the four-signal setup. If the maximum number of supported wanted signals is two, both outer signals are left out.
The wanted signal shall have the same normal GSM modulation with a power level as defined in table 7.8-1.
If BSS supports both EGPRS and ECSD, it is not necessary to perform testing in both modes. If ECSD channel other than E-TCH/F43.2 NT is to be measured a wanted signal level 3 dB above the test signal level specified in subclause 7.3 shall be used. If TCH/FS is not supported, the highest supported of PDTCH/MCS-1 to MCS-4 shall be measured using a wanted signal level 3 dB above the test signal level specified in subclause 7.3.
Table 7.8-1: Test signal input level
|
BTS Type |
Test signal Input Level to receiver TCH/FS |
Power level of Wanted Signal |
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|
E-TCH/ F43.2 NT |
PDTCH/ MCS-5 |
PDTCH/ MCS-6 |
PDTCH/ MCS-7 |
PDTCH/ MCS-8 |
PDTCH/ MCS-9 |
|||||||||
|
GSM 400/GSM 700/GSM 850/ MXM 850/GSM 900/ER-GSM 900/DCS 1800/PCS 1900/MXM 1900 BTS |
‑101 dBm |
-94 dBm |
-98 dBm |
-96.5 dBm |
-93 dBm |
-90 dBm |
-88.5 dBm |
|||||||
|
GSM 900/ER-GSM 900/GSM 700/GSM 850/ MXM 850 micro‑BTS M1 |
‑94 dBm |
-87 dBm |
-91 dBm |
-89.5 dBm |
-86 dBm |
-83 dBm |
-81.5 dBm |
|||||||
|
GSM 900/ER-GSM 900/GSM 700/GSM 850/ MXM 850 micro‑BTS M2 |
‑89 dBm |
-82 dBm |
-86 dBm |
-84.5 dBm |
-81 dBm |
-78 dBm |
-76.5 dBm |
|||||||
|
GSM 900/ER-GSM 900/GSM 700/GSM 850/ MXM 850 micro‑BTS M3 |
‑84 dBm |
-77 dBm |
-81 dBm |
-79.5 dBm |
-76 dBm |
-73 dBm |
-71.5 dBm |
|||||||
|
GSM 900/ER-GSM 900/GSM 700/GSM 850/ MXM 850 pico-BTS P1 |
‑85 dBm |
-78 dBm |
-82 dBm |
-80.5 dBm |
-93 dBm |
-74 dBm |
-72.5 dBm |
|||||||
|
DCS 1800/PCS1900/MXM 1900 micro‑BTS M1 |
‑99 dBm |
-92 dBm |
-96 dBm |
-94.5 dBm |
-91 dBm |
-88 dBm |
-86.5 dBm |
|||||||
|
DCS 1800/PCS1900/MXM 1900 micro‑BTS M2 |
‑94 dBm |
-87 dBm |
-91 dBm |
-89.5 dBm |
-86 dBm |
-83 dBm |
-81.5 dBm |
|||||||
|
DCS 1800/PCS1900/MXM 1900 micro‑BTS M3 |
‑89 dBm |
-82 dBm |
-86 dBm |
-84.5 dBm |
-81 dBm |
-78 dBm |
-76.5 dBm |
|||||||
|
DCS 1800/PCS1900/MXM 1900 pico-BTS P1 |
‑92 dBm |
-85 dBm |
-89 dBm |
-87.5 dBm |
-84 dBm |
-81 dBm |
-79.5 dBm |
|||||||
|
GSM 400/GSM 850/GSM 900/ DCS 1800/PCS 1900/GSM 700 Wide Area multicarrier BTS |
-101 dBm |
-94 dBm |
-98 dBm |
-96.5 dBm |
-93 dBm |
-90 dBm |
-88.5 dBm |
|||||||
|
GSM 400/GSM 850/GSM 900/ DCS 1800/PCS 1900/GSM 700 Medium Range multicarrier BTS |
-95 dBm |
– 88 dBm |
-92 dBm |
-90.5 dBm |
-87 dBm |
-84 dBm |
-82.5 dBm |
|||||||
|
GSM 400/GSM 850/GSM 900/ DCS 1800/PCS 1900/ GSM 700 Local Area multicarrier BTS |
-87 dBm |
– 80 dBm |
-84 dBm |
-82.5 dBm |
-79 dBm |
-76 dBm |
-74.5 dBm |
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The interfering signal is GMSK modulated according to GSM characteristics (with or without a midamble) with a pseudo random bit sequence of at least 511 bits length.
NOTE 1: A 148‑bit sequence of the 511‑bit of a pseudo‑random bit sequence as defined in CCITT Recommendation 0.153 fascile IV.4 is recommended.
i) In case of BTS without multicarrier receiver
The frequency (f) of the interfering signal shall be in the relevant receive band, at least 6 MHz separated from the ARFCN under test. Frequency f is an integer multiple of 200 kHz and at least 2 ARFCNs separated from any identified spurious response in step 9 of the test case in subclause 7.6.2.
ii) In case of multicarrier BTS with multicarrier receiver
The frequency (f) of the interfering signal shall be within the maximum Base Station RF bandwidth, at least 6 MHz separated from the ARFCN(s) under test. Frequency f is an integer multiple of 200 kHz and at least 2 ARFCNs separated from any identified spurious response in 9 in the test case in subclause 7.6.2.
The performances of the wanted signals at 6 MHz or more from the interferer are recorded simultaneously without reallocation of receiver resources during the test.
In case of a multicarrier BTS with multicarrier receiver, the testing duration may be reduced by simultaneously testing different logical channels on different carriers. The error rate shall be evaluated separately for each wanted signal and over the identical time interval for all wanted signals, determined by the logical channel under test requiring the longest test duration.
The interferer shall have one timeslot active, meeting the power/time mask of figure 6.4-1. The transmitted bursts shall be synchronized to but delayed in time between 61 and 86 symbol periods relative to the bursts of the wanted signal. The mean level of the interferer over the useful part of the burst is defined in table 7.8-2.
Table 7.8-2: Interfering signal level
|
Multicarrier BTS |
Micro-BTS |
Pico-BTS |
||||||
|
BTS (dBm) |
WA |
MR |
LA |
M1 (dBm) |
M2 (dBm) |
M3 (dBm) |
P1 (dBm) |
|
|
GSM 400 |
-31 |
-31 |
-26 |
-18 |
– |
– |
– |
– |
|
GSM 900 |
-31 |
-31 |
-26 |
-18 |
-34 |
-29 |
-24 |
-21 |
|
ER-GSM 900 |
-31 |
– |
– |
– |
-34 |
-29 |
-24 |
-21 |
|
GSM 850 |
-31 |
-31 |
-26 |
-18 |
-34 |
-29 |
-24 |
-21 |
|
MXM 850 |
-33 |
– |
– |
– |
-34 |
-29 |
-24 |
-21 |
|
GSM 700 |
-31 |
-31 |
-26 |
-18 |
-34 |
-29 |
-24 |
-21 |
|
DCS 1800 |
-35 |
-35 |
-30 |
-22 |
-33 |
-28 |
-23 |
-26 |
|
PCS 1900 |
-35 |
-35 |
-30 |
-22 |
-33 |
-28 |
-23 |
-26 |
|
MXM 1900 |
-35 |
– |
– |
– |
-33 |
-28 |
-23 |
-26 |
All input signals shall be connected to the receiver via a combining network. The referred power level for all signals shall be the power into the BSS RX antenna connector.
NOTE 2: When testing this requirement, a notch filter may be necessary to ensure that the co channel performance of the receiver is not compromised.
7.8.3 Void
7.8.4 Conformance requirement
Test Environment:
Normal.
Minimum Requirement
For a TCH/FS the RBER of class II, class Ib and the FER the error performance shall not exceed the values given in table 7.3-6.
For a E-TCH/F43,2 NT the BLER or for the highest supported data speed the BLER (or BER) performance shall not exceed the values given in table 7.3-6.
For a PDTCH/MCS-5 or, if not supported, for a PDTCH/MCS-x
with the next higher supported number x the BLER performance shall not exceed the values given in table 7.3-6.
For packet-switched channels, the tests and requirements apply for BTTI without PAN
If TCH/FS is not supported the BLER of the tested PDTCH/MCS-1 to MCS-4 shall not exceed the values given in table 7.3-6.
7.8.5 Requirement Reference
3GPP TS 45.005 subclause 5.2.