Downlink UDP Test


The purpose of the Downlink UDP Test is to measure the downlink receiver performance of a Mobile WiMAX subscriber station (SS).

Upon establishing two way communications, control and broadcast messages are transmitted between the E6651A and the SS, though no user traffic is present. The E6651A can test the receiver performance of the SS by transmitting user data in the downlink direction. In the DL UDP test, the load is applied in downlink direction only, with only short acknowledgement messages sent on the uplink.

A Downlink UDP test can be performed using the default parameters.


To perform the Downlink UDP Test using the default parameters, proceed as follows:

  1. Establish a connection with the SS as described in Interfacing with the Subscriber Station.

  2. Press Mode, BS Emulator, Test Mode to select [DL UDP test].

  3. Press Run Test to select [ON] and perform the DL UDP Test.

Fire-wall software running on the PC connected to the WiMAX SS under test can prevent operation of the UDP test. It is recommended that fire-wall software is disabled during testing.

  1. The protocol message window continues to be updated with DCD/UCD and Periodic Ranging messages and the Base Station Information window now updated with data and PER measurement results.

    UDP Test::

  1. To stop the Downlink UDP Test press Run Test to select [OFF].

When you stop the DL UDP Test, the measurement results are updated. With all packets Lost, no packets acknowledged, a 100% Packet Error rate (PER) is always reported.

Change the Test Set output power, payload, and modulation and repeat the measurement as required to measure the SS receiver performance.

Default Parameters

After Power On or Preset, the DL UDP Test parameters are as follows:

DL Modulation

QPSK (CTC) 1/2

Payload Size
(is size of IP packet including IP header)

8.75 MHz Profile - 576

10 MHz Profile - 576

5 MHz Profile - 288

7 MHz Profile - 576

Packet Interval


Total Packet