Performing Multi-Unit Synchronization

Overview

Multiple test sets either running the cdma2000 test/lab application or the 1xEV-DO test/lab application can be synchronized on the CDMA system time. It is very useful for Hybrid Mode AT/MS tests which requires two test sets, one running the cdma2000 test/lab application and another one running the 1xEV-DO test/lab application to be synchronized.

During the synchronization, the test set providing CDMA system time and 2 seconds trigger signal is called Sync Server while the test set initiates the synchronization and requests the Sync Server to provide CDMA system time is called Sync Client. The test set can act as either a Sync Client or a Sync Server at a time. If as a Sync Server, the test set can process multiple Sync Clients' sync requests.

Prior to the synchronization, the test sets must be properly connected (see Synchronization Connection Setup ) and configured (see Synchronization Configuration Requirements ). When the synchronization is initiated by the Sync Client (see Sync To External Server ). the following procedure is automatically performed.

1. The Sync Client sends a sync request to the Sync Server through the LAN.
2. When receiving the sync request , the Sync Server sends its CDMA system time to the Sync Client. If any error occurs, the Sync Server responds an error to the Sync Client.
3. If the Sync Client receives the response with CDMA system time, it sets its CDMA system time to the received CDMA system time when next 2-second trigger occurs. Once the synchronization completes, the two test sets are synchronized on the CDMA system time within 1 us (see CDMA System Time and Synchronization Information ). The synchronization remains until an event that causes the loss of the synchronization occurs.

   If the Sync Client receives a response with errors or does not receive any response within 3 seconds, the Sync Client posts an error message and the synchronization fails.

Data Source Reset functionality provides a way to reset the data source of Loopback Service Option (SO2, SO9, SO55) on every second boundary of CDMA system time. This functionality can cooperate with Mult-Unit time synchronization to do some tests by using two test sets, for example: soft handoff, mobile receiver diversity, etc. The Data Source Reset is only applicable to the lab application.

Synchronization Connection Setup

The following diagram demonstrates an example of synchronization connection for two test sets.

• Connect one test set's 10 MHz REF IN to another one's 10 MHz REF OUT connector directly, or connect both test sets' 10 MHz REF IN connector to an external instrument that provides 10 MHz timebase signal.
• Connect the Sync Server's TRIG OUT to the Sync Client's TRIG IN connector.
• Connect the two test sets to the LAN using a standard LAN cable, or directly connect them using a crossover LAN cable.

Synchronization Connection Setups for Two Test Sets

Synchronization Configuration Requirements

Prior to the synchronization, you should properly configure the test sets as shown in the table below. For detailed procedure, see How Do I Perform Multi-Unit Synchronization? .

Synchronization Parameters Description

• Ext 8960 IP Addr

  Sets the IP address of the Sync Server on the Sync Client. It must be same as the LAN IP Address of the test set acting as the Sync Server.

  GPIB Command: SYSTem:COMMunicate:LAN:EXTernal:ADDRess

• Sync To External Server

  Initiates the synchronization and sends a sync request to the Sync Server at the address specified by Ext 8960 IP Addr .

  Prior to this action, make sure that you have finished the configurations as shown on Setting Requirements on the Sync Client and Sync Server .

  GPIB Command: SYSTem:COMMunicate:LAN:EXTernal:SYNChronize

• Clear Sync Indications

  Clears all synchronization indications including Sync Annuciators , Client Sync Indication and Server Sync Indication .

  GPIB Command: SYSTem:COMMunicate:LAN:EXTernal:SYNChronize:INDication:CLEar

• LSO Data Reset (This function is only applicable to the lab application.)

  Reset the data source of Loopback Service Options (SO2, SO9, SO55) of two momentums on every even second boundary of CDMA time.

  GPIB Command: CALL[:CELL]:SOPTion:LOOPback:DSOurce:RESet[:STATe]

Synchronization Information and Annuciator

The Local Synchronization Information window and the Sync Annuciator at the left corner of test set screen provide helpful information about the synchronization operation. A typical display for a successful synchronization between two test sets is shown below.

CDMA System Time and Synchronization Information

• Client Sync Indication

  Indicates whether the test set has successfully completed a synchronization when acting as a Sync Client.The possible sync indications as a Sync Client are: Operation Complete , Attempting Sync , or null string (no sync).

• Server Sync Indication

  Indicates whether the test set has successfully completed a synchronization when acting as a Sync Server. The possible sync indications as a Sync Server are: Operation Complete , Processing Sync Request , or null string (no sync).

• Ext 8960 IP Addr (Server)

  Indicates the IP address of the Sync Server specified by Ext 8960 IP Addr .

• Sync Annuciators
  • C OPC : Indicates that the test set has successfully completed a synchronization when acting as a Sync Client.
  • S OPC : Indicates that the test set has successfully completed a synchronization when acting as a Sync Server.
  • CS OPC : Indicates that the test set has successfully completed a synchronization when acting as a Sync Client and then successfully completed a synchronization when acting as a Sync Server. In this case, Operation Complete will be shown on both the Client Sync Indication and Server Sync Indication fields of this test set.
  • Null (no sync).

  GPIB Command: SYSTem:STATus:COMMunicate:LAN:EXTernal:SYNChronize:INDication?

Operating Consideration

In order to perform the synchronization successfully, you must follow the Synchronization Connection Setup to set up the physical connection correctly and follow Synchronization Configuration Requirements to configure the test sets correctly before performing the synchronization.

After the synchronization is done successfully, the followings reasons can cause the loss of synchronization between the test sets.

• The CDMA system time in the Sync Client or Sync Server is changed.
• The CDMA system time in the Sync Client or Sync Server is affected by performing Actions caused uncertainty:

Related Topics

Setting CDMA System Time Parameters

GPIB Commands: CALL:STATus , CALL:CSTime , SYSTem:COMMunicate and SYSTem:STATus

Manual Operation How Do I Perform Multi-Unit Synchronization?