TOP-N Pilot scanning - UMTS 5.7.2

In document Nemo Scanner Guide 7.50 (Page 114-117)

Open the Measurement Properties dialog by selecting Measurement | <device> | General 1.

Properties.

Go to the Pilot scanning, UMTS page to define UMTS-specific Pilot scanning settings.

2.

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.

Measurement period defines the time in milliseconds for which the scanner measures and then reports the result.

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.

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Scanner front-end defines which front-end is used in scanning. The front-end can be defined for each frequency set separately. With the Automatic option, scanner allocates and performs tasks with both RF front-ends.

Scanner demodulation front-end defines the front-end used for demodulation or decoding, such as, cell information decoding, system information decoding, and neighbor list decoding. Available only with TSMW scanners.

Top-N option enables/disables Top-N scrambling code scanning. If enabled, 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.

Note that the Rohde & Schwarz TSMQ, TSML-W, TSML-GW and TSMW scanners support only TOP-N mode and High speed and High dynamic pilot measurement modes. In addition, Data processing method and CPICH Ec/N0 threshold are

supported general settings, and P-SCH, S-SCH, Time of arrival, Delay spread and SIR are supported of the scanning options.

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 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.

When the Missing neighbor detection option is selected, the missing neighbor information event (NMISS) is written in the log file. You can view the missing neighbor information, for example, in a grid view.

When the Neighbor list decoding option is selected, the NLIST (neighbor list) event is written in the log file for both GSM and WCDMA.

Delay profile option enables/disables delay profile scanning. The Channel number field provides a list of channels that can be selected for scanning.

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.

When the System information decoding option is selected, L3 messages are written in the log file.

The Top-N Configuration button will open the Select Channels dialog where you can select channels for pilot scanning.

Note that with UMTS the maximum number of channels that can be scanned is 32 channels, and the maximum number of pilots per each channel is 32.

After making the appropriate settings, click OK and OK again and go to online mode to start the 3.

scanning.

A green light on the scanner Device Status window should start blinking. This means that the 4.

device is working properly and scanning using the default settings. In TOP-N Mode this may take a few seconds.

Click the Start Recording button to start recording the results in an output file.

5.

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5.7.2.1 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.

Page 117

TOP-N Pilot scanning - CDMA/EVDO

In document Nemo Scanner Guide 7.50 (Page 114-117)

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