How Do I Set Up and Use the Frequency Hopping Feature?

Changing the Cell Allocation (CA) Table

The CA Table lists all the channels available to the cell. The entries in the CA Table are important because the MA Tables can only use channels that are in the CA Table. The following procedure details how to change the CA Table.

1. Press the CALL SETUP key.
2. Press Operating Mode ( F1 ) and choose Cell Off from the menu.
3. Press Cell Info ( F6 )
4. Press Cell Lists ( F4 ).

5. Press CA Table ( F2 ). The CA Table menu that appears should look similar to the figure below.

   Note: The entries in the CA Table below contains the test set's default values.

   
      

   NOTE

   The Operating Mode must be Cell Off in order to change any values in the CA Table . If the Operating Mode is not Cell Off all the entries in the CA Table will be gray.

   ---

      

Setting up Frequency Hopping for GSM Traffic Channels

1. Press the CALL SETUP key.
2. Press Operating Mode ( F1 ) and select Active Cell ( GSM, GPRS, or EGPRS ) or GSM BCH+TCH
3. Press TCH Parameters ( F8 )
4. Press the More key on the right side of the screen so 2 of 2 is displayed.
5. Press Frequency Hopping ( F11 ).
6. Press Freq Hopping ( F7 ) and turn the state to On .
7. Press HSN ( F8 ) and choose a Hopping Sequence Number.

8. Press MA Table ( F9 ). A menu similar to the figure below appears that shows all the ARFCNs that are currently in the MA Table for the selected band. The figure below is the default MA Table for the PCS band.

   • To change the state of any ARFCN, you must first set the MA Table Configuration to Manual. Notice when the MA Table Configuration is set to Manual all of the table entries change from gray to black.

   • To change the values that are in the MA Table , you must change the Cell Allocation (CA) Table first by adding/changing ARFCNs for the desired band. See Changing the Cell Allocation (CA) Table for the manual operation procedure for changing the CA Table .

   
9. Press Meas ARFCN ( F11 ) to set the Measurement ARFCN. Use the knob to scroll through the choices for the Measurement ARFCN.
10. Originate a call between the test set and the mobile station.
11. View the frequency hopping. The Spectrum Monitor that is incorporated into the test set is a useful instrument for this purpose. See Viewing Frequency Hopping with the Spectrum Monitor for an example of how you might view frequency hopping. Note: The Traffic Channel ( F9 ) field under the TCH Parms menu disappears from the front panel when frequency hopping is enabled.

Setting up Frequency Hopping for GPRS Packet Data Channels

1. Press the CALL SETUP key.
2. Press Operating Mode ( F1 ) and select Active Cell ( GPRS ) or GPRS BCH+PDTCH .
3. Press PDTCH Parameters ( F9 )
4. Follow steps 4-9 in Setting up Frequency Hopping for GSM Traffic Channels .
5. Start a data connection.
6. View the frequency hopping. The Spectrum Monitor that is incorporated into the test set is a useful instrument for this purpose. See Viewing Frequency Hopping with the Spectrum Monitor for an example of how you might view frequency hopping.

Setting up Frequency Hopping for EGPRS Packet Data Channels

1. Press the CALL SETUP key.
2. Press Operating Mode ( F1 ) and select Active Cell ( EGPRS ) or EGPRS BCH+PDTCH .
3. Press PDTCH Parameters ( F9 )
4. Follow steps 4-9 in Setting up Frequency Hopping for GSM Traffic Channels .
5. Start a data connection.
6. View the frequency hopping. The Spectrum Monitor that is incorporated into the test set is a useful instrument for this purpose. See Viewing Frequency Hopping with the Spectrum Monitor for an example of how you might view frequency hopping.

Viewing Frequency Hopping with the Spectrum Monitor

This procedure assumes that the BCH parameter for Cell Band is set up correctly for your mobile station and that the appropriate RF IN/OUT Amplitude Offsets have been set to offset loss between the mobile station and the test set.

1. Set up frequency hopping for a GSM, GPRS, or EGPRS connection. See Setting up Frequency Hopping for GSM Traffic Channels , Setting up Frequency Hopping for GPRS Packet Data Channels , or Setting up Frequency Hopping for EGPRS Packet Data Channels .
2. Press Instrument Selection.
3. Choose Spectrum Monitor from the Instrument Selection list.
4. Select Frequency Span (F1) and set it to zero. The zero span mode of operation allows you to see whether or not an ARFCN was present in a particular frame.
5. Press the Trigger Setup (F4) and choose Protocol from the Trigger Source list.
6. Press Time Span (F8) and set to 15 ms.

7. Press Trigger Arm (F3) to Continuous. You should see a screen similar to the figure below. The frequency should appear to be hopping as it changes in a cyclic or random way, depending on the setting for the HSN. The figure below is a plot of power vs. time when frequency hopping is enabled and the Measurement ARFCNs are 1 and 10 for the PGSM band.

   

8. The figure below is a plot of power vs. time when frequency hopping is off and when the Measurement ARFCNs are 1 and 10 for the PGSM band.

   

Related Topics

Frequency Hopping

Spectrum Monitor Description

CALL:TCHannel

CALL:(PDTCH|PDTChannel)

CALL:CA