ACK Channel Modulation Type

Last updated: July 22, 2008

This section is only applicable to the lab application and to a test application with the required feature license.

ACK Channel Modulation Type sets the type of the modulation used to transmit the reverse ACK (R-ACK) channel for subtype 2 physical layer. It is sent to the access terminal in the ACKChannelModulationTypeFixedMode attribute in the FETAP Parameter Assignment Message when the test set is configured to ETAP (see Test Application Configuration ) and the ACK Channel Bit Fixed Mode Attribute is set to On.

ACK Channel Modulation Type

ACK Channel Modulation Type	ACK Channel Modulation Type Fixed Mode attribute value (C.S0029-A)	Description
Bi-Polar Keying	0	Indicates the R-ACK channel using BPSK (Bi-Polar keying) modulation where a +1 implies an ACK (positive acknowledgment) and -1 implies a NAK (negative acknowledgment).
On-Off Keying	1	Indicates the R-ACK channel using OOK (On-Off keying) modulation where a 1 implies an ACK (positive acknowledgment) and 0 implies a NAK (negative acknowledgment).

ACK Channel Modulation Type can be changed at any time.

The ACK Channel Modulation Type is displayed on the Call Setup screen in the Application Configuration window when the Session Application Type is set to Test Application , the Release A Physical Layer Subtype is set to Subtype 2 and the ACK Channel Bit Fixed Mode Attribute is set to On in the Active Cell operating mode.

When ACK Channel Bit Fixed Mode Attribute is Off, the AT uses the modulation for the R-ACK channel based on the type of the received packet (Single User or Multi-User). The C.S0024-A air interface standard specifies that the ACK channel modulation is fixed to the BPSK mode when acknowledging a Single User packet and fixed to the OOK mode when acknowledging a Multi-User packet. The test set only supports Single User packets in Test Application configuration, so the AT will always use the BPSK modulation for the R-ACK channel when ACK Channel Bit Fixed Mode Attribute is Off.