Troubleshooting Call Processing Operations

Last updated: January 16, 2009

• Camping and Registration Troubleshooting
• Call Establishment Troubleshooting
• Other Call Processing Problems

Camping and Registration Troubleshooting

• Call Limit must be OFF for any random access procedure such as Location Update or BS Origination (paging) to be successful. See Call Limit State .

• UE Does Not Register with Test Set

  If your UE does not register with the test set, you may need to:

  • Set ATT (IMSI Attach) Flag State to Set , and then turn the UE's power off and on.
  • Increase the Cell Power level.
  • Change the Signalling Radio Bearer (SRB) Parameters to one that is supported by your UE.
  • Consider using the Agilent USIM, which is configured to match the test set's default configuration. See www.agilent.com/find/usim.
  • Ensure that DL Channel is set to a UARFCN that the UE supports, and that the proper Frequency Band Indicator is being transmitted by the test set (see Frequency Band Indicator State ).

• UE Does Not Camp to Test Set at Low Cell Power Levels

  To determine whether to camp to a cell, the UE measures the CPICH RSCP for the cell, and then compares it to the minimum CPICH RSCP required to camp to the cell (the test set specifies a minimum CPICH RSCP of -115 dBm). If the UE's maximum transmit power is less than the Maximum Uplink Transmit Power Level specified by the test set, then the UE must subtract this difference from it's CPICH RSCP value before comparing it to the minimum requirement of -115 dBm. For example, if Maximum Uplink Transmit Power Level is set to +33 dBm, the UE's maximum transmit power is +24 dBm, and the UE measures a CPICH RSCP of -111 dBm, then it will not camp to the test set (-111 dBm - (33 dBm - 24 dBm) = -120 dBm, which is less than the minimum required level of -115 dBm). If Maximum Uplink Transmit Power Level were set to +24 dBm, then the UE would camp to the test set (-111 dBm is greater than the minimum required level of -115 dBm). To ensure that your UE will camp to the test set at low cell power levels, set Maximum Uplink Transmit Power Level to the maximum transmit power for your UE.

• Test Set in Cell Barred List

  If Call Limit State is set to On and you page the UE, the test set will not respond to the UE's PRACH sequence. If the UE reaches the end of its sequence without an acknowledgment from the test set, it may place the test set into its cell barred list. (This may need to occur several times before the UE places the test set into its cell barred list). This means the UE will not look for the test set on its next attempt to camp to a base station. (After a certain amount of time, the UE will resume its consideration of the test set when trying to camp to a base station). If the test set has been added to the UE's cell barred list, you may need to:

  • Change the Local Area Code (LAC) of the test set.
  • Turn the UE off, then back on.
  • With the UE powered on, wait until the UE's cell barred timer expires (this can be as much as 20 minutes), such that it will then search for the test set when trying to camp.

• UE Registers Continuously Due to Integrity Protection Expectation

  If the UE expects integrity protection to be enabled then it will continually attempt to register (as often as every 30 seconds) until the location update procedure successfully starts integrity protection. For integrity protection to be successfully started, the Security Operations setting must be 'Auth+Int' and the rest of the parameters on the Security Settings menu (excluding 'RAND') must match those in the uSIM. See Security Information .

Call Establishment Troubleshooting

• Call Limit must be OFF for any random access procedure such as Location Update or BS Origination (paging) to be successful. See Call Limit State .

• UE Does Not Connect to Test Set

  To successfully establish a call, you may need to:

  • Set RLC Reestablish to Off .
  • Set Uplink Timing Offset to match your UE PRACH signal's offset from the access slot.
  • Set RB Setup Timing Indication (CFN Handling) to Initialise . Note, most UEs do not require that this parameter be changed from its default value of Maintain . Some UEs may not connect to the test set if this parameter is set to Initialise . Also note that call establishment times will increase when RB Setup Timing Indication (CFN Handling) is set to Initialise .
  • Change the Signalling Radio Bearer (SRB) Parameters to one that is supported by your UE.
  • Consider using the Agilent USIM, which is configured to match the test set's default configuration. See www.agilent.com/find/usim.

• UE Does Not Connect to Test Set (HSDPA)

  This section is only applicable to the lab application or feature-licensed test application.

  To successfully establish an HSDPA connection, you may need to:

  • Set RLC Reestablish to Off .
  • Set Uplink 64k DTCH for HSDPA Loopback State to On .
  • Ensure that the CN Domain and PS Domain Information settings are set properly. Before you can establish a connection in the PS domain (i.e. CN Domain set to PS Domain or CS/PS Domain ), the UE must have attached to the test set. To enable this, the PS Domain Information parameter must have been set to Present when the UE registered with the test set. Note that PS Domain Information is set to Absent by default in the Test Application (it is set to Present by default in the Lab Application).

  You must:

  • Set Channel Type to 12.2k RMC + HSDPA .

• UE Does Not Connect to Test Set (HSPA)

  This section is only applicable to the lab application or feature-licensed test application.

  To successfully establish an HSPA connection, you may need to:

  • Set RLC Reestablish to Off .

  You must:

  • Ensure that PS Domain Information is set to Present before the UE registers with the test set ( PS Domain Information is set to Absent by default in the Test Application and to Present by default in the Lab Application).
  • Set Channel Type to 12.2k RMC + HSPA .

• UE Does Not Respond to Test Set's Page

  • If your UE registers with the test set, but does not respond to the test set's page, try this alternate (and usually faster) test set-originated connection procedure:

    1. Connect the UE to the test set, but do not power it on.
    2. Set Operating Mode to Cell Off .
    3. Set Repeat Paging to On .
    4. Set ATT (IMSI Attach) Flag State to Set .
    5. Set Operating Mode to Active Cell .
    6. Select Originate Call and power on the UE.

    After the UE registers with the test set (performs a Location Update), rather than releasing the RRC connection, it will immediately move to connecting the RB test mode call as there is a page request outstanding.

  • If CS Paging Identity Type is set to TMSI , the UE must have a TMSI assigned to it before it will respond to the test set's page. The test set assigns a TMSI to the UE during the Location Update Procedure if TMSI Assignment is set to On before the Location Update Procedure is performed. The TMSI being used to page the UE must be the same as the TMSI assigned to it during registration (the TMSI setting must not have been changed between registration and paging).
  • You may need to change the Signalling Radio Bearer (SRB) Parameters to one that is supported by your UE.
  • Consider using the Agilent USIM, which is configured to match the test set's default configuration. See www.agilent.com/find/usim.

     

• To establish an RB Test Mode call, you must set Paging Service to RB Test Mode and originate the call from the test set. You can not originate an RB Test Mode call from the UE.   

• Some UEs will automatically perform a PDP Context Activation if PS Domain Information is set to Present . If so, before establishing an RB Test Mode or AMR Voice call, you must first select End Call .

     

• Call Setup Fails Due to Transmission of Single PRACH Preamble

  To aid in successful call completion, ensure that your UE does not begin its PRACH preamble sequence at the Maximum Uplink Transmit Power Level or its maximum transmit power (the maximum power it is physically able to transmit). If the UE supports early termination of the PRACH procedure, it will terminate the PRACH preamble sequence once it reaches the maximum transmit level for the cell (as specified by Maximum Uplink Transmit Power Level ) or is maximum transmit power. If a UE supporting early termination begins its PRACH transmission at either of these maximum levels, it will only transmit one PRACH preamble, causing the call setup procedure to fail (the test set requires two consecutive preambles before it will issue a positive indication on the AICH). See Initial PRACH TX Power .

Other Call Processing Problems

• HSPA: To achieve 2 Mbps in the uplink with the downlink configured to H-Set 1 QPSK (534 kbps), set E-DCH RLC SDU Size to at least 4 x 2936 bits = 11744 bits. Note that you must also set RB Test Mode E-DPDCH Max Channel Codes = 2SF2 , grant the UE a large enough serving grant to allow this data rate, and ensure that the UE's transmit power is low enough that the HSUPA channels do not get scaled down.
• HSPA: Once the HSPA connection is established if HSUPA Throughput = 0 kbps, initiate the Single Shot AG action and observe if throughput then becomes non-zero. There is a known issue in some UEs wherein they ignore the RB Setup AG value and use a zero grant upon call establishment.
• HSPA: In order for the UE to receives commands from the test set on the E-RGCH, you must set RB Test Mode E-RGCH Information State and HSPA Cell 1 Connected E-RGCH Level to On (they are both set to off by default).
• HSDPA: If you experience unexpectedly high HSDPA Block Error Ratio results ( lab application or feature-licensed test application only ), ensure that FRC Type is set to a configuration supported by your UE.
• If you set a code channel state to Off (see Downlink Channel Levels Overview ), the test set will not automatically turn it back on if it is needed to perform a call processing operation you've requested (for example, if you set PICH Level to Off , the Originate Call procedure will fail).