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2201R Mobile Tester User Guide

Chapter 3 Performing manual tests and measurements in GSM mode

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7. When you are finished, push the Stop Test soft key.

The measurements stop, and the status indication returns to EDGE Attached.

8. Push the EDGE Detach soft key to finish the EDGE mode.

Interpreting the results

The EDGE BLER menu produces a statistical evaluation of the results of the BLER-USF. The BLER-USF is measured as

a percentage.

The BLER-USF measurement is typically performed at an RF output power level of –104 dBm. The result must not

exceed 2% according to the EDGE specifications.

The results representation on the right-hand side includes a graphical Pass/Fail statement. This verdict depends on

the limits defined in the GSM/GPRS Limits menu. (The limit value for BLER-USF refers to the upper limit because the

lower limit is 0% by nature.)

Measuring the BCS-based BLER

In the BLER-BCS (BLock Error Rate based on the Block Check Sequence) measurement, the mobile receives a lot of

data blocks but transmits only occasionally (when polled).

For the BLER-BCS measurement, the 2201R establishes a Downlink TBF and transmits blocks of data (filled with

random data) to the mobile phone. Every 50 blocks or so, the 2201R requests, just like a real network, an indication

from the mobile whether or not the data have been received correctly by the mobile phone. It acknowledges the

proper reception or reports which blocks have been received in error. The phone can detect reception errors – after

channel decoding – by comparing the transmitted Block Check Sequence (a checksum included with each block) with

the calculated one. Finally, the block error rate is the number of reported errors compared to the whole number of

received blocks.

Procedure

In order to start a test, proceed as follows:

1. Ensure that the wireless device is in the EDGE Attached mode (see ’Setting up the measurements’ on page80).

2. Push the BLER soft key.

The EDGE BLER menu appears.

3. In the Mode selection field, select BLER BCS.

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