An example of the Agilent Mobile WiMAX Protocol Test System is shown here. Depending on the configuration purchased, the system includes N6430A series WiMAX Protocol Test Software, and one or more E6651A Mobile WiMAX Test Sets.
The N6430A series software includes the N6431A TTCN-3 Environment, together with N6432A, N6433A, N6434A, N6442A and/or N6443A Adaptors depending on the configuration selected. These components allow TTCN-3 Test cases to be executed on the E6651A WiMAX Test Set.
The E6651A contains RF and MAC layer emulation functions. The E6651A can emulate a WiMAX base station or mobile station, providing an RF interface to the user-supplied equipment under test.
The N6430A series software provides logging within the TTCN-3 environment. For more detailed MAC/PHY layer protocol logging, it is also possible to connect the Agilent N6421A Protocol Logging and Analysis software to the E6651A.
The N6430A series software and the N6421A protocol logging application should be loaded and run on separate computers and connected to the E6651A using a private Ethernet network. Separate Ethernet ports can be added to the computers if necessary to provide connection to a public or corporate Ethernet network.
Many protocol test scenarios can be emulated using a single E6651A. For some hand over test scenarios, it may be necessary to emulate more than one WiMAX cell. Additional E6651As can be added to the system and controlled by a single instance of N6430A series software to build up multi-cell systems.
The currently supported WiMAX protocol testing methodologies require user control of the equipment under test. In the future, the WiMAX standard will expand to enable future revisions of the N6430A series software to control the equipment under test by means of a standardized Test Interface (TI).
Refer to "What is the N6430A Series Test System?" for a more detailed view of the implementation.
With the WiMAX industry still in its infancy, at the time of writing, incompatibility between WiMAX devices is still quite normal. Reasons for incompatibility can include:
• Equipment under test not conforming to current WiMAX selected version of IEEE 802.16e standards i.e. being developed around a version of the standard other than 802.16 - 2004 Cor2/D3.
• Equipment designed to operate using WiMAX profiles that are other than those currently supported by the WiMAX Forum™ validation program and the E6651A i.e. other than profile 1A and 3A.
• Implementation defects in equipment under test and ETSI Test Cases.
Information about which test cases are considered "high confidence", together with recommended system revision and configuration information is published in the “Release Notes” spreadsheet delivered with each Agilent software update. Test Case defect information is held in the ETSI Mantis system. Links and additional information are available at www.agilent.com/find/pctdownloads.
The E6651A Mobile WiMAX Test Set has two protocol modes of operation. When operating as a stand-alone test set, the E6651A uses an internal real-time state-machine implementation of the IEEE 802.16 - 2004 Cor2/D3 protocol stack. In this mode, the product is configured to be as compatible as possible with a variety of interpretations and revisions of the IEEE 802.16e standard. It will operate with equipment that conforms to the IEEE 802.16 - 2004 Cor2/D3 revision of the standard, and in many situations will operate effectively with equipment conforming to earlier versions and containing defective implementations. When operating as part of a protocol test system with the N6430A series, the real-time protocol stack in the E6651A is disabled and replaced by the functionality of the external TTCN-3 system. In this mode, the test system is typically less accommodating of IUT defects and non Cor2/D3 implementations. TLVs from older versions of the standard will often not be supported by the Codec. Test cases are written to fail in the event of equipment under test deviations from the prescribed standard.