Handoff

Last updated: November 27, 2008

Handoff State

The handoff state is a transitory state (see TAP/ETAP/MCTAP Data Connection Processing Lifecycle ).

To query the state of the data connection, see Data Connection State Synchronization .

Explicit versus Implicit Handoffs

There are two types of handoffs that the test set can perform, implicit and explicit.

Implicit handoffs are simply a side effect of changing any parameter that is negotiated using a Traffic Channel Assignment message (such as PN Offset, DRC Channel Gain, or Channel). For example, an implicit handoff occurs when you type in a new channel number in the Channel field or select a new Cell Band . You can perform an implicit handoff at any time. If you perform an implicit handoff while in idle state, the settings are immediately applied by the test set and there is no signalling to the access terminal. If you change the channel while in the session open state, the settings are immediately applied, the session is preserved, and a Sector Parameters message is sent to the access terminal. The session timer (see Fixed Settings ) is restarted to give the AT full time to respond to the change. If you perform an implicit handoff while in the connected state, the settings are applied and a Traffic Channel Assignment message is sent to the AT, directing it to the new band or channel (the Channel record in the message contains System Type, Band Class and Channel Number fields).

An explicit handoff can only be performed while in the connected state. Before performing an explicit handoff, you must first specify the handoff cell band and/or handoff channel (the cell band and channel you want to handoff to). Then, when you initiate the explicit handoff using the CALL:HANDoff command or by selecting the Execute Handoff soft key, the AT is directed to the handoff cell band and/or handoff channel by a Traffic Channel Assignment message. This allows you to set up the handoff channel and band in advance, and then direct the AT to a new cell band and channel with a single command during testing, which can save test time (instead of moving the AT first to the new cell band and then moving it again to the desired channel, you move it directly to the new cell band and channel).

In summary, you can perform an implicit handoff while in any state. You can only perform an explicit handoff while in the connected state. Performing an explicit handoff allows you to hand off to a new band and channel using a single command.

Multi-carrier Handoff

In multi-carrier configuration (see Multi-carrier Multi-unit (MCMU) ), multi-carrier handoff settings is also available in Handoff Setup menu on the Main unit, in which Handoff Aux Carrier X State determines whether Aux unit X is about to perform an explicit handoff to an associated handoff Aux Carrier X Channel (where X is 1 or 2 denoting Aux unit 1 or Aux unit 2). Note that handoff Aux Carrier X Channel is only available when the associated Handoff Aux Carrier X State is set to On .

On this condition, when Local Testset Configuration is set to Main , External Device X status shows Connected , and Handoff Aux Carrier X State is On , multi-carrier handoff can be performed according to the Handoff Aux Carrier X Channel.

Programming Usage

Implicit handoff:

• Changing the current cell band: CALL:BAND
• Changing the current channel: CALL:CHANnel

Explicit handoff:

• Specifying the handoff cell band and channel: CALL:SETup
• Initiating the handoff: CALL:HANDoff
• Programming example: Step 6: Reconfigure Test Set and Mobile Station Connection Parameters

Manual Operation

Implicit handoff:

• How Do I Change Call Parameters?

Explicit handoff:

• How Do I Perform a Handoff?