What is the N6430A Series Test System?

Introduction

The Agilent N6430A Series Protocol Test System block diagram is based closely on TTCN-3 (Testing and Test Control Notation version 3) industry standards.

TE (TTCN-3 Executable)

The N6431A TTCN-3 Environment provides a graphical user interface and software framework for other components of the system. The tool enables TTCN-3 test cases to be loaded, edited or created, compiled and executed. It includes logging functions and the ability to automate sequences of tests or campaigns. The N6431A is based on Testing Technologies IST GmbH’s TTWorkbench® product.

WiMAX TTCN-3 test cases can be portable from one test platform to another. To enable test case portability, the functions available to TTCN-3 programmer through the TRI (TTCN-3 Run Time Interface) have been standardized by ETSI and the WiMAX Forum™. Test cases written in the TTCN-3 language are compiled to form the TE (TTCN-3 Executable). WiMAX conformance test cases are created for the WiMAX Forum by ETSI. You can also create your own TTCN-3 test cases.

TTCN-3 Environment Examples

         

Test Adaptors

The N6432/3A/4A and N6442/3A include adaptors that connect the standardized TRI interface, available to programmers, to the unique implementations of MAC and PHY contained within the E6651A Mobile WiMAX Test Set. The SA (System Adaptor) provides a message portal to enable TTCN-3 programs to send and receive protocol messages directly to the MAC layer within the E6651A. The PA (Platform Adaptor) provides TTCN-3 programs with a selection of External Functions. External Functions are defined by ETSI and implemented by a combination of unique software components within the PA and the E6651A. N6432/3A/4A and N6442/3A also contain the message coder/decoder (Codec). The Codec uses information from the IEEE 802.16e standards to encode and decode messages from the high-level message descriptions within the TTCN-3 test cases to a form that can be utilized directly by the protocol stack within the E6651A.

Operation

The E6651A Mobile WiMAX Test Set exchanges messages with the SA and PA in the N6430A series PC-based system using a proprietary protocol carried over a private Ethernet connection. The Test Set contains an implementation of the IEEE 802.16e protocol MAC (Media Access Control) layer and PHY (Physical) layer that includes and RF interface that can be used to connect to the equipment under test. When operated as a stand-alone Test Set, the E6651A MAC layer operates autonomously to emulate a WiMAX base station. When operated in TTCN mode, and connected to the external N6430A series system, the Test Set’s upper MAC is disabled and replaced by the functionality of the TTCN-3 script being executed within the N6430A series environment. In this mode, the system can emulate either a Mobile Station or a Base Station.

The N6421A Protocol Logging Application can be connected to the E6651A Mobile WiMAX Test Set to capture MAC and PHY message exchange. The Protocol Logging Application can operate with the E6651A in either a stand-alone configuration, or in configurations where the E6651A is used with the N6430A series system.

Agilent N6421A Protocol Logging and Analysis

 

TTCN-3 industry terminology collectively describes the N6430A series and E6651A Mobile WiMAX Test Set as the ‘Lower Tester’. In this context, the protocol IUT (Implementation Under Test) is defined as the MAC protocol component within the Equipment under test (Mobile Station or Base Station). Other components exist within the User Equipment under test to support the testing of the IUT protocol. These include a user interface required to support the execution of some test cases serving as a TTCN-3 ‘Upper Tester’. In the future, the WiMAX Forum will standardize an Ethernet-based connection between the test system and IUT to enable tests to be fully automated.