Troubleshooting the Two-Cell Test System

Troubleshooting the Two-Cell Test System

Last updated: September 2, 2009

Description

Possible Setup Issues

  • Important : DUT IP Address must be set to a different value in each test set in the two-cell test system.
  • The operating mode in both test sets must be set to Active Cell in order to perform cell transitions, as this is the only operating mode that provides signaling to the mobile.
  • While operating in the GSM/GPRS/EGPRS application/format, the connection type must be set to Auto in both test sets of the two-cell test system in order to maintain IP-based data connections during cell reselection. Any other connection type setting terminates the active data connection during cell reselection and does not restart the data connection once cell reselection is complete.
  • It is recommended that you configure the neighbor cell list in each test set to contain the other test set's information (using the SIB 11 Cell Info List in W-CDMA/HSPA or the Cell Lists in GSM/GPRS/EGPRS). This enables the mobile to measure the other test set before transitioning to it (some mobiles will not perform a "blind" handover) and allows you to view the mobile's measurement reports for the test set. Ensure that you have properly configured the mobile measurement reports for measuring the destination test set's current configuration by using the Compressed Mode settings in W-CDMA/HSPA (the HSUPA packet data service in the test set does not currently support compressed mode) or the Measurement Reports settings in GSM/GPRS/EGPRS.
  • Network Control Order in the GSM/GPRS/EGPRS application determines how the mobile should perform cell reselections. If Network Control Order is set to NC0 or NC1 in the test set to which the mobile is currently attached, it may not respond to network-initiated attempts at cell reselection. Also, if the test set to which the mobile is attached has Network Control Order set to NC2 , the mobile may not perform autonomous cell reselection.

Operating Considerations

  • Mobile initiated cell reselections made during GSM/GPRS/EGPRS PS data transfer mode may result in a TBF aborted by the mobile with no indication provided to the test set as to why the abort is occurring. In this circumstance, a warning appears at the test set from which the mobile is moving.
  • When performing a cell reselection from GSM/GPRS/EGPRS while actively transferring data, data may arrive for the mobile at the originating test set after the mobile has moved from the originating test set, but before it has arrived at the destination test set. In this case, the originating test set posts an error, but the reselection is not impacted. Once the mobile is established at the destination test set, all subsequent data is tunneled to the mobile at the destination test set.
  • Since the two-cell test system allows you to control when handovers and cell reselections occur, the measurement reports that are returned periodically by the mobile are not used by the test sets. you must order network-initiated cell transitions; it is not possible for the test sets to automatically order the transitions based on measurement reports from the mobile
  • The DUT IP Address setting is inaccessible if the mobile is connected to the current test set but using an IP address originally assigned by the other test set. When a mobile has an active PDP context with one test set and transitions to another, a tunnel is created to route data to and from the mobile via the originating test set. During tunneling, the mobile uses the DUT IP Address provided by the originating test set, not the DUT IP Address of the serving test set. In this case, the IP data trace is shown on the Data Throughput Monitor of the originating test set; only the OTA data trace is shown on the destination test set's Data Throughput Monitor. Refer to the External Device Connection documentation for additional information.
  • The External Device Connection is disconnected as a result of a full preset. You must re-establish the External Device Connection before continuing two-cell testing.

Related Topics

Two-Cell Test System

How Do I Set Up and Test Cell Selection and Transitions?

How Do I Make an External Device Connection?

External Device Connection

Configuring the Test Set's LAN