This topic describes the Baseband parameters for the various Advanced LTE-A Pro Uplink component carrier types, including E-UTRA, eMTC, and NB-IoT.
Additional parameter setup tables for are described in these topics:
General (Advanced LTE-A Pro FDD Uplink)
Fading contained in Waveform (multipath only) (Advanced LTE-A Pro FDD Uplink)
Choice: AUTO | 1 | 2
Default: AUTO
Double-click or use the drop-down menu to set the oversampling ratio.
If you select AUTO, the signal generator automatically sets an optimized oversampling ratio for the current setup.
Base Sampling Rate, Oversampling Ratio, Total Sample Points, and Waveform Generation Length are related as follows: Total Sample Points = Base Sampling Rate (MHz) × Oversampling Ratio × 1000 × Waveform Generation Length (ms). See Base Sampling Rate and Waveform Generation Length.
Base Sampling Rate is a sampling rate without Oversampling Ratio (OSR). There is a relation among Base Sampling Rate, OSR, Total Sample Points and Waveform Generation Length as follows.
Total Sample Points = Base Sampling Rate (MHz) x OSR x 1000 x Waveform Generation Length (ms)
Example:
In the case: System BW = 5 MHz, OSR = 1 (Auto), Waveform Generation Length = 10 ms
Total Sample Points = 7.68 (MHz) x 1 x 1000 x 10 (ms) = 76800 (Points)
The software sets the Base Sampling Rate based on the System Bandwidth (BW) as follows:
System BW = 1.4 MHz, Base Sampling Rate = 1.92 MHz.
System BW = 3 MHz, Base Sampling Rate = 3.84 MHz.
System BW = 5 MHz, Base Sampling Rate = 7.68 MHz.
System BW = 10 MHz, Base Sampling Rate = 15.36 MHz.
System BW = 15 MHz, Base Sampling Rate = 23.04 MHz.
System BW = 20 MHz, Base Sampling Rate = 30.72 MHz.
When Carrier Aggregation has multiple E-UTRA carriers or E-UTRA carrier of 15 MHz System Bandwidth and NB-IoT carrier(s), the Base Sampling Rate = 30.72 MHz.
Displays Base Sampling Rate for each System BW or multicarrier condition. When System BW is 200 kHz, Base Sampling Rate is 1.92 MHz.
Base Sampling Rate is a sampling rate without Oversampling Ratio (OSR). There is a relation among Base Sampling Rate, OSR, Total Sample Points and Waveform Generation Length as follows.
Total Sample Points = Base Sampling Rate (MHz) x OSR x 1000 x Waveform Generation Length (ms)
Example:
In the case: System BW = 200 kHz, OSR = 1 (Auto), Waveform Generation Length = 20 ms
Total Sample Points = 1.92 (MHz) x 1 x 1000 x 20 (ms) = 38400 (Points)
View the waveform length, displayed in points. This parameter is read only and its value is automatically calculated as follows: Total Sample Points = Base Sampling Rate (MHz) × Oversampling Ratio × 1000 × Waveform Generation Length (ms). See Oversampling Ratio, Base Sampling Rate, and Waveform Generation Length.
Range: 10.0 to 100.0%
Default: 100.0%
Set the clipping (limit) level of the I/Q waveform before filtering. (100.0% = no clipping)
Range: 10.0 to 100.0%
Default: 100.0%
Set the clipping (limit) level of the I/Q waveform after filtering. (100.0% = no clipping)
Sets the frequency offset for the carrier relative to the signal generator’s frequency setting.
The range of the parameter is coupled to the Oversampling Ratio, the Base Sampling Rate, the System Bandwidth and the max ARB Sample Clock of the connected signal generator.
Frequency Offset and Cell ID are always editable, even if Auto Carrier Aggregation Configuration is on.
In the case (1) or (2), auto configuration is done for Frequency Offset and Cell ID.
(1) When any action "Add CC" or "Delete CC" or "Copy CC" or Change System BW is done and Auto Carrier Aggregation Configuration parameter is On.
(2) When Auto Carrier Aggregation Configuration parameter is changed to On from Off.
Auto configuration sets Cell ID same as Component Carrier Index.
If Auto Carrier Aggregation Configuration is set to off, auto configuration does not work.
Stand-Alone: Sets the frequency offset for the carrier relative to the signal generator’s frequency setting. The range of the parameter is coupled to Oversampling Ratio, Base Sampling Rate, System Bandwidth and the max ARB Sample Clock of the connected signal generator.
Guard-Band: Frequency Offset is calculated by Coupled E-UTRA Carrier, Position vs Coupled E-UTRA Carrier and Offset from Coupled E-UTRA Carrier Edge.
In-Band: Frequency Offset is calculated by Coupled E-UTRA Carrier and In-Band RB Offset.
Range: -60.000 to 20.000 dB
Default: 0.000 dB
Sets the power level in dB for the selected carrier in a multiple carrier configuration, relative to the power settings defined for the other carriers in the configuration.
You can ignore this parameter for single carrier configurations. In single carrier configurations, the amplitude of the signal is determined by the Amplitude setting in the Instrument node.
The carrier power level set with this parameter determines how the total RF power level (set with the Amplitude parameter in the Instrument node) is shared by the carriers in a multiple carrier configuration. The power, set in dB, is relative to the power, in dB, of the other carriers.
Example: Assume a two-carrier configuration with the RF power level set at -10 dBm in the instrument node. If Carrier 1 is set to 0 dB and Carrier 2 is set to 0 dB, then each carrier will be transmitted with the same power level. This means that each carrier will be transmitted at -13 dBm to maintain the total power output by the instrument at -10 dBm.
Range: 0.000 to minimum (waveform generation length - 1 ns or 10 ms - 1 ns) (us)
Default: 0.000 (us)
Specifies the length of timing offset. The maximum value of the range depends of Waveform Generation Length.
If Timing Offset cannot be divided by sampling period (1 / Base Sampling Rate / Oversampling Ratio), it is rounded to the nearest sample point.
Timing offset shifts the waveform relative to its original position and the Event 1 frame trigger marker signal. Each offset increment represents a period of time equal to the inverse value of the sampling frequency (see table below). As the waveform bit stream is shifted within a frame, the leftover bits wrap around to occupy the time between the original position and the offset value. This is advantageous in a multicarrier configuration because you can vary the timing offset of each carrier to reduce the probability of all carriers adding in phase and minimize the crest factor in the composite waveform. In a single carrier configuration, the timing offset has no effect on the crest factor, and therefore, should be set to 0.
|
Sampling Frequency |
Time Value per Offset Increment (1/sampling frequency) |
Channel Configuration (Bandwidth and Resource Blocks) |
|---|---|---|
|
1.92 MHz |
520.8 ns |
1.4 MHz, 6 RB |
|
3.84 MHz |
260.4 ns |
3 MHz, 15 RB |
|
7.68 MHz |
130.2 ns |
5 MHz, 25 RB |
|
15.36 MHz |
65.1 ns |
10 MHz, 50 RB |
|
23.04 MHz |
43.4 ns |
15 MHz, 75 RB |
|
30.72 MHz |
32.55 ns |
20 MHz, 100 RB |
|
30.72 MHz |
32.55 ns |
Multicarrier |
Range: 0 to 359 degrees
Default: 0 degrees
Set the initial phase of the carrier.
Choice: On | Off
Default:
E-UTRA/eMTC: On
NB-IoT: Off
Double-click or use the drop-down menu to turn the auto symbol rolloff length configuration on or off.
Range: 0 to 400 Ts
Default:
E-UTRA/eMTC: 15 Ts
NB-IoT: 0 Ts
The cyclic prefix used with SC-FDMA modulation in LTE results in a discontinuity between SC-FDMA symbols. Windowing is used in the Signal Studio for 3GPP LTE software to reduce spurious signal generation between symbols caused by this discontinuity. Symbol Rolloff Length sets the windowing length in Basic Time Units. Adjusting the Symbol Rolloff Length can improve ACPR performance, however this may result in degraded EVM performance.
Basic Time Unit (Ts) = 1/(15000 x 2048) seconds
Choice: On | Off
Default: On
Double-click or use the drop-down menu to turn the baseband filter on or off. In most testing conditions, Keysight recommends using the baseband filter (Baseband Filter = On) to achieve a balance between ACPR and EVM performance.
Choice: On | Off
Default: Off
Double-click or use the drop-down menu to turn the baseband filter on or off. Appears in NB-IoT only.
Baseband Filter off is for EVM optimized condition.
Baseband Filter on is for ACP optimized condition.
Choice: Standard | Narrow | Custom
Default: Standard
Double-click or use the drop-down menu to set ACP Optimized Filter Type. Appears in NB-IoT only. Narrow filter provides better spectrum performance, but EVM may degrade.
When Baseband Filter (ACP Optimized) is on, this parameter is visible.
Range: 1 to 113
Default: 12
Enter a value for Filter Length. Appears in NB-IoT only. The number of Taps varies in proportion to this value.
This parameter is visible only when ACP Optimized Filter Type is Custom.
Range: 1 to 82
Default: 9
Enter a value for Filter Bandwidth Factor. Appears in NB-IoT only. Cut-off frequency varies in proportion to this value.
This parameter is visible only when ACP Optimized Filter Type is Custom.