The Wi-Fi Alliance is a global, non-profit industry association that promotes wireless technologies. The alliance provides its members with testing and certification programs to ensure the interoperability of wireless products based on the IEEE 802.11 specification. Since the certification program began in 2000, more than 3000 products have been “Wi-Fi Certified.”[1]

When the Wi-Fi Alliance certification process and programs were originally developed, the vast majority of 802.11 clients were PC-centric network equipment or network clients, and certification testing adequately addressed them. In subsequent years, the number of non-PC-centric Wi-Fi devices has grown significantly, along with a dramatic increase in non-standard 802.11 devices.

These non-PC-centric devices, which include cell phones, gaming devices, and MP3 players, require a different testing approach than PC-based client devices. As a result, the Wi-Fi Alliance has developed a new test engine methodology that allows station tests to be streamlined for any type of product. The key component is a framework for client testing that is extensible to any Wi-Fi client and does not compromise the integrity of the comprehensive series of Wi-Fi testing processes.

In defining the new test engine methodology, the Wi-Fi Alliance ASD technical task group proposed a framework referred to as the Wi-Fi Alliance test engine, or simply the test engine. Its three key areas include:

1. Station configuration and control: The methodology defines a standard interface that allows vendors to design stations that can be configured for the tests and then stimulated to perform the actions required. Because the devices tested lack standard user interfaces such as a keyboard or mouse, the interface is defined independent of the vendor's implementation.

2. Test traffic generation: A large part of interoperability testing requires the transmission and reception of traffic by the device under test (DUT) as a way to measure throughput, connectivity and functionality. The DUT station initiates or terminates this traffic, and the test engine methodology provides a traffic generation element for integration into the DUT, as well as guidelines to create this capability on the station. The traffic generator is specifically designed for devices with limited memory and processing power.

3. Test results measurement: A methodology is required to measure and report results. The test engine uses the Azimuth ADEPT-WFA tool and test automation to enable traffic analysis and reporting that is independent of the capabilities of the station DUT. The methodology uses intelligent capture and analysis techniques to validate connectivity, performance and functional testing.

In addressing these areas of station testing, the test engine provides a scalable approach that is suitable for the growing variety of Wi-Fi enabled products. The resulting test solution, required to certify products using the Wi-Fi Alliance test engine methodology, includes five key components (See Figure 2):

1. DUT software: The Wi-Fi traffic generator (WTG) software and DUT agent reside on the DUT. The WTG software generates the Wi-Fi traffic used in the tests, and the DUT agent software enables communications to configure and control the DUT.

2. Control PC software: The control software implements the parser for the control application programming interface (API) to convert commands to USB, enabling vendors to control their devices through their native control protocol or command set.

3. Capture engine: The capture engine provides vendors with the mechanism to capture and time-stamp all detected wireless and wired traffic (referred to as promiscuous mode) for analysis.

4. Test engine management tool: The management tool controls and configures the DUT via the control PC and executes the test plan. In addition, the management tool controls the test bed equipment, including access points (APs), to ensure a stable environment.

5. Alliance test bed: The test bed selects the clients and access points used as reference devices for interoperability, helping vendors verify their products in a multivendor marketplace.

The Wi-Fi Alliance provides sample software in source code form to its members. This software implements the DUT software and the control agent on the control PC, including an implementation of the DUT control API. This software is designed to prepare DUTs for Wi-Fi certification.

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