RF test innovations target MIMO

Expected ratification of the IEEE 802.11n standard might be nearly a year away, but products embodying the multiple-input, multiple-output (MIMO) technology the standard specifies are already appearing. While some companies are waiting to develop "pre-n" chips until ratification comes closer, many others, such as Broadcom, have already entered the market, reports Electronic News (Ref. 1). Even those opposed to the so-called "pre-n" label, like Airgo Networks, are offering their own MIMO devices.

Option B7Z provides developers with a graphical user interface and a set of signal-analysis capabilities pertaining to IEEE 802.11n MIMO and other RF applications. Courtesy of Agilent Technologies.

Option B7Z can be used with Agilent's Infiniium digital oscilloscopes and 89600 Series VXI-based analyzers, which meet the IEEE 802.11n requirement for 36-MHz signal bandwidths. The Infiniium Series scopes, with a digitizing capability of up to 40 Gsamples/s, can measure 802.11n signals directly, without down-conversion.

Azimuth Systems has also announced a platform for Wi-Fi vendors wanting to test their draft 802.11n-based products. Called the "Azimuth MIMO Functional Test solution," the platform targets test of interoperability among MIMO products; performance, including maximum throughput; and backward compatibility to legacy devices.

Azimuth marketing director Graham Celine described the platform as a combination of software automation and hardware to support 802.11 tests, with the bulk of the product value in the software. It operates in conjunction with Azimuth's W-Series platform, which employs Azimuth's SmartMotion technology to simulate devices in motion, its testMAC technology to emulate golden devices, and its Real2Real architecture for system test.

Celine noted that the MIMO Functional Test solution focuses on the aspects of MIMO that have limited channel dependence, while the company's ACE MIMO channel emulator serves for performance and range testing.

The Agilent and Azimuth products can test subassemblies and systems as well as chips, but as Celine pointed out, "Chipset vendors are the pioneers and as such are very actively involved in [802.11n] testing. We expect, as with all our other tests, that [the new platform] will be of huge value to the equipment manufacturers as well."