AT Directed Packets

Last updated: May 24, 2006

3GPP2 C.S0033-A section 8.4.3.5 specifies :

When the access terminal under test is in the Connected State and a 100% packet activity is required (see Fixed Settings , Forward Packet Activity), the access network equipment shall conform to the following rules for the generation of packets:

• All the slots during the test will contain Forward Traffic Channel packets or Control Channel packets (100% packet activity).
• Unless otherwise explicitly stated, the serving rate of the access terminal under test shall be 50%. Therefore, at every slot that a new Forward Traffic Channel packet is to be generated, the access network equipment shall generate a uniformly distributed random number "x" between 0 and 1.
  • If x > 0.5, the Forward Traffic Channel packet shall be directed to the access terminal under test.
  • Otherwise, the Forward Traffic Channel packet shall be a filling packet emulating other users' activity.
• The packets emulating other users must be of the same length as the length of the packets generated for the access terminal under test. The Preamble MAC index used for the filling packets shall be any valid MAC index number different from the one used for the access terminal under test.

The test set implements this requirement but allows for the percentage of packets directed to the AT under test to be varied. The AT Directed Packets specifies what percentage of the packets are directed to the AT under test. This parameter can be set between 0 and 100%, in 1% increments. The default value is 50%. The AT Directed Packets is displayed on the Call Setup screen in the Application Configuration window.

If the AT under test has enough processing power to receive more than 50% of the valid FTAP or FETAP test packets, you can increase the AT Directed Packets parameter and speed up PER testing, optimizing throughput. For more description on the FTAP or FETAP, see C.S0029 Test Application Specification Description (TAP/ETAP) .