Pilot scanning can be used for scanning unknown pilots or the strongest pilots.
After the scanner is connected and activated in Nemo Outdoor, open the Measurement 1.
Properties dialog by selecting Measurement | <device> | Pilot Scanning Properties.
There is a separate page for each supported technology. All options are not available for all 2.
technologies.
Cyclic prefix defines the type of signal the scanner is set to measure. With Autodetect selected, the scanner will automatically detect the appropriate signal type.
CPICH Ec/No threshold defines the minimum level for the CPICH Ec/No. If the values are below the threshold, the pilots are not reported.
Channel style refers to the bandwidth of the channel.
Data processing method defines how the scanned data is processed by the scanner. In aggregate method, the sum of all peak pilot Ec/Io values above the PN threshold is calculated. If there are no peaks above the PN threshold, value -30 dB is returned for WCDMA.
Pilot window mode defines the position of the chips that are searched for pilot across in regard to the ideal pilot position (0 chip delay for a given pilot).
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Pilot measurement mode defines the measurement mode for pilot scanning.
• In High speed mode scanning speed is higher but sensitivity is lower. In high speed mode, weak pilots may be undetected.
• In High dynamic mode scanning speed is lower but sensitivity is higher.
Pilot Ec/I0 threshold defines the threshold level for the pilot Ec/I0. If the values are below the threshold, the pilots are not scanned.
RSSI threshold determines a valid path (in dB). Subtracting the set value from a path with a maximum correlation value gives the lower limit of the valid path.
Top-N option enables Top-N scrambling code scanning. Scanner will report results from N best scrambling codes. Number of pilots field defines how many pilots are reported by scanner in Top-N mode. With Venture scanners, this option must be always enabled.
CINR option activates/deactivates Carrier to Interference and Noise Ratio measuring. Carrier refers to either reference signal power or sync signal power depending on the selected signal type.
Time offset refers to the number of samples between P-SCH Primary Synchronization Signal arrival time with respect to receiver frequency reference that is derived from GPS reference time.
Sync signal refers to the ratio between the synchronization channel, i.e., primary and secondary signal received power and the interference and noise from the same synchronization signal set.
Reference signal refers to the ratio between the reference signal received power (RSRP) and the interference and noise from the same reference signal set.
Time of arrival defines if the selected scanner will measure the time of arrival for each scrambling code. The time of arrival value is relative to GPS time and is measured in chips.
Delay option enables/disables delay profile scanning. Delay is defined as the measured difference between the expected arrival time (GPS time) and the actual arrival time of the maximum peak above the PN threshold. It is reported in chips.
Delay spread defines if the selected scanner will also measure the delay spread value (in chips) for each scanned scrambling code. Delay spread is determined as the difference between the last and first component to break the threshold set in PN Threshold.
P-SCH defines if the selected scanner will measure the P-SCH Ec/N0 value for each scrambling code.
SIR (signal to interference ratio) defines if the selected scanner will measure the SIR value for each scrambling code.
S-SCH defines if the selected scanner will measure the S-SCH Ec/N0 value for each scrambling code.
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By clicking the Select Channels button, you can access the Select Channels dialog.
3.
Select the Show channels as frequencies option to view frequencies instead of channel numbers.
Add channels to the Selected list by selecting a channel from the Available list and clicking the Add button.
Remove channels from the Selected list by selecting a channel and clicking the Remove button.
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When you select LTE channels, you can also define some channel-specific settings. In the LTE 4.
Channel Specific Settings dialog, select the channel from the Selected channels list and define the settings.
♦ Note that the available options are device specific.
Channel style refers to the bandwidth of the channel.
Uplink-downlink configuration refers to LTE TDD frame structure.
Frame structure type 2 is applicable to TDD. Each radio frame of length
T
f= 307200 ⋅ T
s= 10 ms
consists of two half-frames of length
153600 ⋅T
s= 5 ms
each. Each half-frame consists of five subframes of length3 0720 ⋅T
s= 1 ms
. The supported uplink-downlink configurations are listed in the table below where, for each subframe in a radio frame, “D” denotes the subframe is reserved for downlink transmissions, “U” denotes the subframe is reserved for uplinktransmissions and “S” denotes a special subframe with the three fields DwPTS, GP and UpPTS.
One slot, Subframe #2 Subframe #3 Subframe #4
Subframe #0 Subframe #5 Subframe #7 Subframe #8 Subframe #9
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Frame structure type 2 (for 5 ms switch-point periodicity):
Uplink-downlink
4. After making the appropriate settings, click OK and OK again and go to online mode to start the scanning.
5. A green light on the scanner Device Status window should start blinking. This means that the device is working properly and scanning using the default settings.
6. Click the Start Recording button to start recording the results in an output file.
6.4.2.1 Data processing method – Peak vs Aggregate
If the multipath components are significantly lower than the peak, their contribution will be negligible and the aggregate will be the same as the peak. However, if one or more multipath components are close to the peak component in power, its power combined with the peak component’s power will be larger than either of them alone. In the case where a multipath component is the same strength as the peak the aggregate will be twice the power, or 3dB higher than the peak. Thus, the aggregate will always be the same as or larger than the peak.
As a practical matter, many multipath components are typically present in an urban environment, where there are many surfaces (e.g., buildings) which can reflect the radio signal. By contrast, there may be few or no multipath components in a rural environment.
The difference between Aggregate and Peak is variable. Probably the difference will lie in the range of 0 to 4 dB. If the multipath components are small, they will have no contribution and aggregate will be equal to peak (0 dB difference). In the case above where one multipath is equal to the peak, the doubling of power gives +3dB to the aggregate. There might be cases where two components are the same strength as the peak and this would result in an aggregate +4.7dB relative to the
peak. Naturally, if another component becomes higher than the “peak”, it becomes the new peak.
Aggregation does not happen over time, but over multipath components that are all simultaneously present.
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7 TROUBLESHOOTING SCANNERS
If a Scanner synchronization failed error message appears in the Output window, the scanner is working properly, but the scanner did not find strong enough a CPICH in a short time period.
Nevertheless, the measurement will go on normally.
If a Scanner GPS locking failed error message appears in the Output window, the scanner is working properly, but the scanner GPS has no fix or is not connected. The measurement will go on normally, but the scanner accuracy is not as good as it is when the scanner GPS has a fix
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8 TECHNICAL SUPPORT
If you have questions on or beyond this documentation about Nemo tools, please contact our technical support service through Nemo Support Portal at http://nemosupport.anite.com, call us (local phone numbers can be found in chapter Phone and email support) or send us an email at
nemosupport@anite.com. Note that for full support you need to have the Maintenance Agreement.