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MIMO Testing Made Easy

If you’re developing Wi-Fi or WiMAX equipment with multiple-input/multiple-output (MIMO), you have a test problem. To ensure your new products meet the needs of your customers and comply with the standards organization’s test procedures, you need a way to subject the product to MIMO signals. That’s no easy task, especially if you’re testing 4-by-4 MIMO products.

Real-world, over-the-air testing is almost impossible to implement, as it is so difficult to duplicate the wide range of channel fading and multipath conditions that will provide an adequate evaluation. That’s why channel emulation was created and has become the way to test MIMO products. That’s also why Azimuth Systems has announced additions to its ACE400WB 4-by-4 MIMO WiMAX channel emulator (see the figure).

The original ACE400WB was introduced last year in a 4-by-4 configuration. The latest additions provide configurations for multiple 2-by-2, unidirectional, and bidirectional testing configurations with no recabling required. In addition, three new ACE 400WB models are optimized for 2-by-2 MIMO, MIMO Wi-Fi (802.11n), and unidirectional testing.

New multilink support provides flexibility for selecting topology configurations that can be controlled from the GUI, allowing different models, velocities, and devices to be combined with minimum effort. Multilink supports unique use cases, such as testing multiple mobile stations connected to a single basestation for collaborative uplink or testing handoff of a single mobile station between two basestations.

Azimuth’s channel emulation system uses sophisticated channel models to recreate conditions that occur in real-world wireless transmission. These models serve as statistical characterizations of specific environments that are constantly changing due to variables like radio movement, the unique environment, people, cars, and other nearby obstructions and objects like trees.

Some standards organizations define specific models for testing, like the ITU M.1225 Pedestrian B and Vehicular A channel models for testing WiMAX products and the 1EEE 802.11n channel models A through F for Wi-Fi testing.

The ACE 400WB is a complete test solution for WiMAX, including Wave 2 certification, and Wi-Fi 802.11n. This platform can scale to address the forthcoming LTE, UMB, and 802.16m 4G standards that all employ MIMO, spatial multiplexing, adaptive antennas, and/or beamforming in some form.

Azimuth Systems

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