Active Cell Operating Mode

Active Cell Operating Mode

Last updated: December 2, 2008

This section contains the following:

Active Cell Operating Mode

The operating mode changes the way in which the test set interacts with the mobile station. Active cell operating mode provides active signaling between the mobile station and the test set's base station emulator. That is, the test set has active control of the uplink and downlink, including all signaling operations, uplink demodulation and downlink generation.

In active cell operating mode the base station emulator, using the test set's modulated source, generates a downlink (base station to mobile station direction) broadcast channel (BCH) which represents a cell. The mobile station can "camp" to this signal, just as it would camp to a cell on a real network, and perform an attach procedure to register the mobile station with the test set. The test set and mobile station can then initiate connections that allow for the transfer of information, like a GSM voice call or a data connection using GPRS or EGPRS.

Test set test modes are used when it is not possible, or not desired, to communicate via over-the-air signaling with the mobile station, but downlink stimulus and uplink measurements are still needed. For more details on test modes provided by the test set, see Test Mode Operating Modes .

   
NOTE
Trying to set any of the network configuration parameters while the operating mode is Active Cell generates the following error:

GSM/GPRS operation rejected; Attempting to set <MCC|MNC|LAC|NCC|BCC|RAC> while generating a BCH .

   

Setting the Test Set's Operating Mode to Active Cell

The test set's operating mode is set using the command, CALL:OPERating:MODE . Specifying the `CALL' parameter selects Active Cell Mode.

On the test set's front panel, the Active Cell operating mode parameter is coupled with the serving cell parameter.

Serving Cell

The serving cell setting determines type of base station the test set emulates when the operating mode is set to Active Cell. This parameter determines what information is sent on the broadcast channel and the messages, parameter, and fields that the test set uses when signaling the mobile station.

You can set the serving cell to either GSM, GPRS, or EGPRS. The choice of serving cells available to you depends on the licenses you have for the test or lab application you are currently using. When the serving cell is GPRS or EGPRS, the test set provides GPRS or EGPRS specific information on the BCH, such as System Information 13 data. This setting is independent of the Connection Type setting, which determines the type of call or data connection permitted.

   
NOTE
When the serving cell is GPRS or EGPRS, it is still possible to make GSM voice calls. If the mobile station is GPRS or EGPRS capable it still sees the cell as being GPRS/EGPRS enabled and may attempt an attach procedure. It is still possible to initiate and accept GSM voice calls when the mobile station is GPRS attached.

When the serving cell is GSM, a GPRS or EGPRS capable mobile should not attempt to attach or be capable of accepting a data connection.

   

   
NOTE
The test set currently does not provide a combined GPRS + EGPRS operating mode. Therefore, a mobile station that supports GPRS but not EGPRS will not be able to attach when the serving cell is set to EGPRS. The GPRS serving cell setting should be used instead.
   

Configuring the Serving Cell

To set the Serving Cell remotely, use the following process:

On the test set's front panel, the Serving Cell is coupled with some of the Operating Mode parameters. To set the serving cell manually, press the CALL SETUP key and Operating Mode ( F1 ). Select the type of cell you want to be active. The coupling between operating mode and serving cell is shown in the following table.

MUI Operating Mode settings and Serving Cell

Operating Mode

Serving Cell

Active Cell (GSM)

 GSM

Active Cell (GPRS)

 GPRS
Active Cell (EGPRS) EGPRS

GSM Serving Cell (or Active Cell (GSM) Operating Mode)

When the serving cell parameter is set to GSM, the test set emulates a base station that supports only GSM. The mobile station "camps" to the test set and it is possible to originate GSM voice calls from either the mobile station or the test set. This allows the following measurements to be performed under essentially identical conditions to that which the mobile station would experience on a real network.

   
NOTE
The Auto connection type is the only valid connection type when the serving cell is set to GSM. See Connection Types for more information.
   

To set the Serving Cell remotely, use the GPIB command CALL[:CELL]:BCHannel:SCELl . To set the Serving Cell manually, press the CALL SETUP key, Operating Mode ( F1 ), then select Active Cell(GSM) .

GPRS Serving Cell (or Active Cell (GPRS) Operating Mode)

When the serving cell parameter is set to GPRS, the test set emulates a base station that supports both GSM and GPRS. The mobile station "camps" to the test set and performs an attach procedure to register the mobile station with the network. It is still possible to originate GSM voice calls from either the mobile station or the test set. Additionally, a Packet Data Traffic Channel (PDTCH) can then be established and data can be transferred in both the downlink and uplink directions. This allows measurements to be performed under essentially identical conditions to that which the mobile station would experience on a real network.

   
NOTE
Use the GPRS serving cell if your mobile station supports GPRS, but not EGPRS. When the serving cell is EGPRS, a GSM + EGPRS BCH is provided. There is currently no combined GPRS + EGPRS mode available. Therefore, a mobile station that supports GPRS but not EGPRS will not be able to attach when the serving cell is set to EGPRS.
   

The Connection Type parameter is used to set the type of data connection. See Connection Types for details about the different connection types and when it is appropriate to use each.

For GPRS mobile stations which support a single uplink timeslot or two adjacent uplink timeslots, the following measurements can be made when a data connection has been established.

Additionally, all the measurement specified in GSM Serving Cell (or Active Cell (GSM) Operating Mode) still apply when a GSM voice call is established.

To set the Serving Cell remotely, use the GPIB command CALL[:CELL]:BCHannel:SCELl . To set the Serving Cell to GPRS manually, press the CALL SETUP key, Operating Mode ( F1 ), then select Active Cell(GPRS) .

For a typical scenario detailing the steps you might take to test a GPRS mobile station, see Testing a GPRS Mobile Station .

EGPRS Serving Cell (or Active Cell (EGPRS) Operating Mode)

When the serving cell parameter is set to EGPRS, the test set emulates a base station that supports GSM and EGPRS. The mobile station "camps" to the test set and performs an attach procedure. It is still possible to originate GSM voice calls from either the mobile station or the test set. Packet Data Traffic Channel (PDTCH) can be established so data can be transferred in both the downlink and uplink directions. The additional EGPRS capability activated by setting the serving cell to EGPRS includes modulation and coding schemes that differ from those used for GPRS. This allows measurements to be performed under essentially identical conditions to that which the mobile station would experience on a real network.

   
NOTE
When the serving cell is EGPRS, a GSM + EGPRS BCH is provided. There is currently no combined GPRS + EGPRS mode available. Therefore, a mobile station that supports GPRS but not EGPRS will not be able to attach when the serving cell is set to EGPRS. The GPRS serving cell setting should be used instead.
   

The Connection Type parameter is used to set the type of data connection. See Connection Types for details about the different connection types and when it is appropriate to use each.

For EGPRS mobile stations which support a single uplink timeslot or two adjacent uplink timeslots, the following measurements can be made under essentially identical conditions to that which the mobile station would experience on a real network:

Additionally, all the measurement specified in GSM Serving Cell (or Active Cell (GSM) Operating Mode) still apply when a GSM voice call is established.

To set the Serving Cell remotely, use the GPIB command CALL[:CELL]:BCHannel:SCELl . To set the Serving Cell to EGPRS manually, press the CALL SETUP key, Operating Mode ( F1 ), then select Active Cell(EGPRS) .

Persistent Attach

The Persistent Attach parameter provides a way for you to switch between a GPRS serving cell and EGPRS serving cell if the operating mode is Active Cell.

When the Persistent Attach state is OFF the test set's connection status will become IDLE when the operating mode is switched between Active Cell (serving cell GPRS) and Active Cell (serving cell EGPRS).

When the Persistent Attach state is ON the connection status will stay in the ACTIVE or PDP ACTIVE state when the operating mode is set to Cell Off. When the connection status remains in the ACTIVE or PDP ACTIVE state the GMM remains in the registered state which allows the mobile station to request an RAU without reattaching. Also, when Persistent Attach is ON, the information that is reported from the test set is not cleared when the operating mode is set to Cell Off.

To change between Active Cell (serving cell GPRS) and Active Cell (serving cell EGPRS) when the Persistent Attach state is ON and the operating mode is Active Cell (serving cell GPRS or EGPRS), you must first change the operating mode to Cell Off before switching to a different serving cell. For example, if the operating mode is Active Cell (serving cell GPRS) and you want to change to Active Cell (serving cell EGPRS) you must first change the operating mode to Cell Off, change cell parameters if desired, and finally change the operating mode to Active Cell (serving cell EGPRS). Persistent Attach will not work if the operating mode is changed to an operating mode other than Active Cell (serving cell GPRS or EGPRS) at any point in the transition from a GPRS serving cell to an EGPRS serving cell or vise versa.

The command to change the Persistent Attach state is CALL:MS:PATTach[:STATe] . Persistent Attach State is a Cell Parameter. See How Do I Change Cell Parameters? for instructions to manually change cell parameters.