Cell Parameters

Last updated: March 16, 2009

The test set broadcasts cell-specific information on the BCCH. This information is needed by the UE to successfully communicate with the network.

The Cell Parameters fall into one of four categories:

• Settings that cannot be changed while in Active Cell Operating Mode (switch to Cell Off Operating Mode to change these settings):
  CTCH Allocation Period ( lab application only )
  CBS Frame Offset ( lab application only )
  AICH Transmission Timing ( lab application only )
  SCCPCH/PRACH Configuration ( lab application only )
  
  
• Settings that can be changed in Active Cell Operating Mode, but only when the call status is idle: 
  Default DPCH Offset (DOFF)  
  
• Settings that can be changed in Active Cell Operating Mode, but only when the call status is idle. If BCCH Update Page is set to Auto and you change these settings while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change these settings while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).
  PS Domain Information Mobile Country Code (MCC)  
  Mobile Network Code (MNC)  
  Local Area Code (LAC) Routing Area Code (RAC) Cell Identity ATT (IMSI Attach) Flag State DRX Cycle Length (CN Domain) Primary CPICH TX Power Uplink Interference Constant Value Network Mode of Operation Equipment Identity Request
• Settings that can be changed at any time (including while on a call in active cell operating mode):
  BCCH Update Page  
  RB Setup Timing Indication (CFN Handling)

Cell Parameter Descriptions

• BCCH Update Page

  If BCCH Update Page is set to Auto , when you change a parameter that causes a Broadcast Channel (BCCH) Update Procedure (SIB Contents) (which only occurs when call status is idle), the test set updates its BCCH information and sends a Paging Type I message to the UE telling it to re-read the BCCH. If BCCH Update Page is set to Inhibit , when you change a BCCH parameter that would normally cause a BCCH Update procedure, the test set updates its BCCH information but does NOT send a Paging Type I message to the UE.

  If your UE does not support the BCCH Update procedure, set this field to Inhibit . However, note that the UE will then be unaware of the changes to the BCCH. To force your UE to re-read the BCCH, you can do one of the following:

  • Originate a call and then release it.
  • Cause the UE to perform a cell re-selection by changing the Primary Scrambling Code and Cell Identity .
  • Turn the UE off and then back on.

  You may also use this field to reduce the amount of signalling between the test set and UE as follows: if you need to change many BCCH parameters, set this field to Inhibit , change all of the parameters except one, set this field to Auto , then change the final parameter. That way, only one Paging Type I message is sent to the UE. See Broadcast Channel (BCCH) Update Procedure (SIB Contents)

  GPIB command: CALL[:CELL]:BCCHannel:UPDAtepage .

  This parameter can be changed at any time.

• PS Domain Information

  This setting indicates to the UE what type of services are supported by the test set. When PS Domain Information is set to Absent , the CN Domain System Information List sent by the test set in SIB 1 (see 3GPP TS 25.331 10.2.48.8.4) includes CN Domain System Information for the CN Domain Identity of CS Domain only (see 3GPP TS 25.331 10.3.1.2). When PS Domain is set to Present , the CN Domain System Information List also includes CN Domain System Information for the CN Domain Identity of PS Domain.

  Setting PS Domain Information to Present allows UEs that require both of these CN Domain Identities to camp to the test set (see Performing a Location Update (CS Domain Registration) ). PS Domain Information must be set to Present before a UE will initiate PS services with the test set.

  Note, 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 .

  The test application supports the PS Domain Information setting even though it does not support UE-initiated PS services (feature-licensed test applications support test set-initiated HSPA connections in the PS domain). If the UE attempts to initiate a PS service, the test application allows it to attach, but if the UE attempts an Activate PDP Context Request, it is rejected with a cause of "Feature Not Supported" (see Activate PDP Context Reject ).

     

  NOTE

  PS Domain Information is set to Absent by default in the Test Application (it is set to Present by default in the Lab Application).

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  GPIB command: CALL[:CELL]:PSDomain .

  This parameter can only be set when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• Mobile Country Code (MCC)

  GPIB command: CALL:MCCode .

  This setting can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• Mobile Network Code (MNC)

  GPIB command: CALL:MNCode .

  This setting can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• Local Area Code (LAC)

  GPIB command: CALL:LACode .

  This setting can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• Routing Area Code (RAC)

  The RAC is a fixed length code (of 1 octet) identifying a routing area within a location area (see 3GPP TS 23.003 4.2). The CN Domain identifier for Packet Switching (PS) consists of the PLMN-Id, Local Area Code (LAC) and the RAC (see 3GPP TS 23.003 12.2).

  GPIB command: CALL:RACode .

  This parameter can only be set when PS Domain Information is set to Present and call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• Cell Identity

  3GPP TS 25.331 10.3.2.2 defines cell identity as a 28 bit number which unambiguously identifies a cell within a PLMN (Public Land Mobile Network). The Cell Identity parameter in the test set allows you to input a decimal value between 0 and 268435455, which is then transmitted to the UE as a 28 bit number, identifying the test set.

  GPIB command: CALL[:CELL]:IDENtity .

  This setting can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• ATT (IMSI Attach) Flag State

  IMSI Attach is a core network procedure that utilizes the Location Update procedure (see Performing a Location Update (CS Domain Registration) ). When ATT (IMSI Attach) Flag State is Set , the test set signals the UE to perform IMSI Attach. While the test set does not actually perform the core network IMSI Attach procedure, signalling the UE to perform IMSI Attach causes it to perform a Location Update every time it camps to the test set. If the UE is IMSI Attached, in some circumstances it will request an IMSI Detach before proceeding with other call processing operations. If the UE sends the test set an IMSI Detach Indication while the call status is idle, the test set simply releases the RRC Connection and then returns to Idle.

  If ATT (IMSI Attach) Flag State is Not Set , the UE will only register when it determines that it has camped to a new cell (indicated by the Mobile Network Code (MNC) , Mobile Country Code (MCC) and Local Area Code (LAC) settings).

  GPIB command: CALL:ATTFlag .

  This setting can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• DRX Cycle Length (CN Domain)

  DRX (Discontinuous Reception) Cycle is defined in 3GPP TS 25.304 3.1 as "Individual time interval between monitoring Paging Occasion for a specific UE." 3GPP TS 25.331 8.6.3.1a states "The UE shall determine its idle mode paging occasions and PICH monitoring occasions for that CN domain..., based on the stored CN domain specific DRX cycle length, when using DRX in idle mode." This setting determines the length of the DRX cycle that the UE uses while in idle mode.

  This parameter is useful for idle mode battery drain testing.

  See Page Indicator Channel (PICH) and Repeat Paging for related information.

  Note, this setting does not configure the UTRAN DRX Cycle length coefficient described in 3GPP TS 25.331 8.6.3.2.

  GPIB command: CALL[:CELL]:DRX:CLENgth .

  This setting can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• Open loop power control settings - these settings are used by the UE to determine the initial transmit power of the first PRACH preamble. See 3GPP TS 25.331 8.5.7 and Initial PRACH TX Power .

  These settings can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change these settings while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change these settings while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

  • Primary CPICH TX Power

    GPIB command: CALL:PCTPower .

    Primary CPICH Tx Power is a parameter transmitted to the UE on the BCCH by the test set. It is not the actual transmit power level of the test set's CPICH.

  • Uplink Interference

    In an actual W-CDMA system, the base station measures the interference present in its cell and then reports this value to the UE. In the test set, you must set this value manually.

    GPIB command: CALL:UINTerferenc .

  • Constant Value

    The Constant Value allows you to specify an offset in the power level of the UE's initial PRACH transmission.

    GPIB command: CALL:CVALue .

• RB setup Timing Indication (CFN Handling):

  Background Information

  While connected to a cell, the UE maintains a CFN (Connection Frame Number) counter which is based upon the cell's SFN (System Frame Number). According to 3GPP TS 25.331 8.5.15.2, for FDD: CFN = (SFN - (DOFF div 38400)) mod 256).

  When the UE is handed off to a new cell while in the CELL_DCH state, it can be ordered to maintain its CFN counter (continue to increase CFN by 1 every frame) or to re-initialize it based on the SFN of the target cell (the UE must read the BCCH of the target cell to do so). The UE is ordered to maintain or re-initialize its CFN counter by the Timing Indication information element sent in the message that initiates the handover (Timing Indication is also called cfnHandling, see 3GPP TS 25.331 s10.3.6.18, 10.3.6.24, 10.2.22, 10.2.33, and 10.2.50).

  If Timing Indication is set to Initialise, the UE must read the BCCH of the target cell and re-initialize its CFN counter (this is called a "Timing Re-Initialised Hard Handover," see 3GPP TS 25.331 8.3.5.1). If Timing Indication is set to Maintain, the UE maintains its CFN counter (this is called a "Timing Maintained Hard Handover," see 3GPP TS 25.331 8.3.5.2).

  Test Set Implementation

  From the test set, you may specify whether the UE should initialise or maintain its CFN counter for several events associated with handing off to a new cell. Note that the UE does not actually hand off to a new cell for any of these events, it is still being served by the test set. Thus, whether the UE initialises or maintains its CFN counter, its CFN counter always simply increments by 1 each frame because it is always determined by the test set's SFN. (Note that in the test set, DOFF is never greater than 2560, see Current DPCH Offset . Thus, DOFF div 38400 is 0, and CFN = SFN mod 256.) When the UE initializes its CFN, it reads the test set's BCCH to determine the SFN. When the UE maintains it CFN, it does not read the test set's BCCH. The resulting CFN is the same either way.

  Note that according to 3GPP 25.331 v5.17.0 s8.6.6.28, timing re-initialized reconfigurations are intended to be exclusively used for hard handovers (i.e. where the UE changes UARFCNs and/or all Primary Scrambling Codes for all links in the active set as part of the reconfiguration, see 3GPP TS 25.331 v5.17.0 s8.6.6.3a). 25.331 states that the UE's behavior is undefined if the network sets the Timing Indication IE to Initialise on a non-hard handover (i.e. where the UARFCNs and one or more Primary Scrambling Codes remain unchanged as part of the reconfiguration).

  You can specify whether Timing Indication is set to Maintain or Initialise for several events using the following settings:

  • PCR Timing Indication (CFN Handling)
  • CM PCR Timing Indication (CFN Handling)
  • TCR Timing Indication (CFN Handling)
  • RBR Timing Indication (CFN Handling)
  • RB Setup Timing Indication (CFN Handling)

    You can specify whether the Timing Indication information element sent in the RB Setup message is set to Maintain or Initialise. See RB setup Timing Indication (CFN Handling): above for more details.

    The most common usage scenario includes a Timing Indication of Maintain in the RB Setup message, wherein the UE is instructed to use the timing from the same cell it used for its RRC Connection. A Timing Indication of Initialise would indicate to the UE that it is being moved between cells between the RRC Connection and RB Setup stages of call establishment. Since 25.331 states that a timing re-initialised non-hard handover is undefined, if you establish a call with RB Setup Timing Indication (CFN Handling) set to Initialise , the call attempt may fail or be rejected by the UE.

    GPIB command: CALL[:CELL]:RBSetup:CFNHandling .

    This parameter can be changed at any time.

  Note that setting Timing Indication to Initialise for any of these messages may cause an increase in the time it takes to complete any associated procedures (such as making a call or performing a hard handover).

• Default DPCH Offset (DOFF)This setting determines the value of the Default DPCH Offset information element (3GPP TS 25.331 s10.3.6.16). The Default DPCH Offset information element is signalled to the UE in the RRC Connection Setup and RB Setup messages. Default DPCH Offset can be used to change the DPCH Frame Offset (tau _DPCH ) to 0, 1, 2, 3, 4 or 5 x 512 chips during call establishment. See Current DPCH Offset for more information.

  GPIB command: CALL:DPCHannel:DOFFset

  This parameter can only be set when call status is Idle . To change the DPCH Frame Offset while on a connection, see Transport Channel Reconfiguration .

• CTCH Allocation Period

  This setting is only applicable to the lab application.

  The CTCH Allocation period specifies the frames within a 4096 system frame cycle that is allocated to the CTCH. This parameter, along with the CBS Frame Offset determine which TTI intervals in the FACH to be utilized by the CTCH. The the range for this parameter is 1 to 4096 minus the CBS Frame Offset. Additionally, this setting must be greater than the CBS Frame Offset.

  GPIB command: CALL[:CELL[1]]:CTCHannel:APERiod

  This parameter can only be set when operating mode is Cell Off .

• CBS Frame Offset

  This setting is only applicable to the lab application.

  The CTCH Frame offset indicates which frame within the system frame to begin the CTCH allocation. This parameter, along with the CTCH Frame offset determine which TTI intervals in the FACH to be utilized by the CTCH. The setting range for this parameter is 0 to one less than the CTCH Allocation Period.

  GPIB command: CALL[:CELL[1]]:CTCHannel:FOFFset

  This parameter can only be set when operating mode is Cell Off .

• Network Mode of Operation

  A UMTS network can operate in either Network Mode I or Mode II. In Mode I the MSC (Mobile Switching Centre) and the SGSN (Serving GPRS Support Node) are connected together. In Mode II these two network elements are not inter-connected. The primary consequence of Mode I is that UEs are allowed to perform combined GPRS Attach & IMSI Attach procedures and combined Location Update & Routing Area Update procedures. A combined procedure is a single over-the-air procedure that the network treats as if two separate procedures have occurred. For instance a UE that does a Combined GPRS Attach is treated by the network as having done both a GMM GPRS Attach and a MM IMSI Attach. For a combined procedure to work the SGSN network node (which tracks GPRS Attached status) must have a link to its associated MSC (which tracks IMSI Attach status). Then when the SGSN receives a Combined GPRS Attach message it can inform the MSC that the UE has also done an IMSI Attach. In Mode II the MSC and SGSN are not inter-connected so the UE is forced into doing separate GPRS Attach and IMSI Attach procedures and separate Routing Area Update and Location Area Update procedures. In Mode I the UE is not required by the standards to use the combined procedures, although it is likely to do so. For a UE to initiate a combined procedure it must have both of the separate procedures outstanding.

  In the test set, Mode I allows the UE to perform a Combined Attach (a GPRS Attach with Attach Type set to Combined Attach in the Attach Request message) to register in both the PS and CS Domains simultaneously. During a Combined Attach, the Data Connection State transitions as follows: Idle-Setup-Attaching-Idle. Upon completion of the Combined Attach, MM Status is IMSI Attached and GMM State is Attached . Note, PS Domain Information must be set to Present for the UE to perform a Combined Attach. If PS Domain Information is set to Absent and Network Mode of Operation is set to 1 when the UE registers, the UE simply performs an IMSI Attach.

  In Mode II, the UE must perform separate GPRS Attach and IMSI Attach procedures to register in both the PS and CS Domains. During this process, the Call Connection State transitions as follows: Idle-Setup-Registering-Releasing-Idle, then the Data Connection State transitions as follows: Idle-Setup-Attaching-Idle (often several seconds later).

  Note that in Mode I it is likely that only IMSI will be reported by the UE (and not IMEI); whereas in Mode II it is likely that both IMSI and IMEI will be reported by the UE. This is because in response to a registration attempt from the UE (Location Update Request or GPRS Attach Request) the test set sends a single Identity Request, which requests the UE's IMSI unless the UE already included its IMSI in its Location Update Request or GPRS Attach Request. Only if the UE already included its IMSI will the test set request the UE's IMEI in the Identity Request message. Thus, in Mode II when the UE performs a Location Update Request (which usually includes its IMSI), the test set requests the UE's IMEI with its Identity Request. In Mode I, the UE usually sends a P-TMSI in its Attach Request, so the test set requests the IMSI with its Identity Request instead of the IMEI.

  GPIB command: CALL[:CELL]:NMOPeration

  This setting can only be changed when call status is Idle . If BCCH Update Page is set to Auto and you change this setting while your UE is camped to the test set, the test set performs a Broadcast Channel (BCCH) Update Procedure (SIB Contents) . If BCCH Update Page is set to Inhibit (the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see BCCH Update Page for more details).

• Equipment Identity Request

  This parameter can be set to any of the following:

  • IMEI - The application requests the IMEI only. This behaviour is the same as firmware releases prior to E.00.
  • EISV - The application requests the International Mobile Equipment Identity and Software Version Number (IMEISV). The IMEI is extracted from the IMEISV for use by the test set's front panel user interface.
  • ALL - The application requests both the IMEI and IMEISV using two separate identity request procedures.

  This setting applies to the following procedures: Location update, GPRS attach, Routing area update, CS paging response, PS paging response, and CS/PS Service request.

  GPIB Command: CALL[:CELL]:EIDentity:REQuest]

• AICH Transmission Timing

  This setting controls the acquisition indicator channel's transmission timing in SIB5. This determines the timing of the uplink PRACH preamble-to-preamble and preamble-to-message part:

  • When set to 0, preamble-to-preamble timing = preamble-to-msg = 15360 chips (3 access slots); preamble-to-acquisition indicator = 7680 chips
  • When set to 1, preamble-to-preamble timing = preamble-to-msg = 20480 chips (4 access slots); preamble-to-acquisition indicator = 12800 chips

  Therefore there are 2 slots difference between the uplink PRACH and AICH burst when the AICH transmission timing is 1.

  GPIB Command: CALL:AICHannel:TRANsmission:TIMing

• SCCPCH/PRACH Configuration

  This setting determines the configuration of the SCCPCH and PRACH channels:

  • When set to Signaling Only, the historical SCCPCH/PRACH configuration that only supports the PCCH/CCCH/DCCH logical channels is used.
  • When set to Signaling + Traffic, then the SCCPCH and PRACH are configured to support PS data DTCHs as well as the PCCH/CCCH/DCCH logical channels. The Signaling + Traffic mode is required for use with the CELL_FACH state on a PDP Context, however it also works for all other call types.

  GPIB Command: CALL:CCPChannel:SECondary:CONFigure