Adjacent Channel Leakage Ratio (ACLR) Measurement Description
Last updated: January 16, 2009
How is an Adjacent Channel Leakage Ratio Measurement Made?
Adjacent channel leakage ratio (ACLR) measures the relative power at ± 5 MHz and ± 10 MHz offsets from the uplink channel. Power is measured through a Root-Raised Cosine (RRC) filter with a rolloff of a=0.22, and a bandwidth equal to the chip rate (3.84 MHz). The ± 5 MHz measurements are referred to as the upper and lower first adjacent channels; the ± 10 MHz measurements are referred to as the upper and lower second adjacent channels. This measurement is defined in 3GPP TS 34.121, sections 5.10 and 5.10A, Adjacent Channel Power Leakage Ratio (ACLR).
Measurements for individual offsets can be turned off to increase measurement speed when these measurements are not needed.
Measurements can be displayed in either numeric or graphical form. When the graphical display is used (shown below), limits can be set for each offset to form a "limit line." When a limit is exceeded, the status changes from "Pass" to "Fail."
Adjacent Channel Leakage Ratio Measurement Parameters
-
Multi-Measurement Count: (see
Statistical Measurement Results
).
-
-5 MHz Offset State
-
+5 MHz Offset State
-
-10 MHz Offset State
-
+10 MHz Offset State
-
Trigger Arm: (see
Trigger Arm (Single or Continuous) Description
).
-
Trigger Source
You must specify how you want to trigger the measurement using the
Trigger Source
setting.
You may set
Trigger Source
to the following: (for more information on these trigger types, see
Trigger Source Description
).
-
Auto: if the UE is synchronized to the test set, it uses protocol triggering; otherwise, it uses immediate triggering.
-
External
-
HS-DPCCH:
This setting is only applicable to the lab application or a feature-licensed test application.
When
Trigger Source
is set to
HS-DPCCH
, you can specify on which uplink subframe the measurement triggers using the
HS-DPCCH Trigger Subframe Alignment
setting.
Trigger Source
can only be set to HS-DPCCH when
Channel Type
=
12.2k RMC + HSDPA
or
12.2k RMC + HSPA
.
-
Immediate
-
Protocol: Derived from the 10 ms downlink DPCH frame clock.
-
Trigger Delay
You can move the measurement interval (666.7 us = 1 timeslot) relative to the trigger using the
Trigger Delay
setting.
-
HS-DPCCH Trigger Subframe Alignment
This setting is only applicable to the lab application or a feature-licensed test application.
When
Trigger Source
is set to
HS-DPCCH
, you can specify on which uplink subframe the measurement triggers. You can then use the
Trigger Delay
setting to move the measurement interval (666.7 us = 1 timeslot) relative to that subframe boundary.
-
Measurement Timeout: (see
Measurement Timeouts
).
Adjacent Channel Leakage Ratio Input Signal Requirements
-
For this measurement the test set's receiver uses autoranging to adjust for the level of the signal being measured; therefore, the expected signal level does not need to be specified during measurement setup.
-
The frequency of the signal being measured must be in the range of 800 MHz to 1000 MHz, 1700 MHz to 1990 MHz, or 2480 MHz to 2580 MHz.
-
The level into the test set's RF IN/OUT connector must be in the range of +5 dBm to +28 dBm, in a 3.84 MHz bandwidth.
-
The uplink must be of constant in-channel power for the duration of this measurement. This requirement has implications for correct power control configuration, and uplink dynamics in HSDPA and HSUPA.
Adjacent Channel Leakage Ratio Measurement Calibration
You must calibrate this measurement using the
Calibrate Measurements
procedure (see
Calibrating the Test Set
).
|
top
of page