The tools and tricks of WLAN test

The rapid development of IEEE 802.11 WLAN technology has resulted in a dearth of literature on how to test WLANs, contends author Tom Alexander, who sets out to fill the gap. He largely succeeds with this book, which serves as a readable introduction to WLAN test without getting bogged down in the details of the IEEE specs.

Alexander begins with a WLAN introductory chapter before moving on to test and measurement. He begins chapter 2 with the basics, employing a target-practice analogy to define uncertainty, precision, and resolution. He divides instrumentation into physical-layer, protocol, and installation categories, with the last category consisting mostly of ad hoc “walk test” systems that combine spectrum analyzers, sniffers, traffic sources, GPS receivers, and meters. Subsequent chapters provide details on each of these areas.

Alexander provides a good overview chapter on WLAN test environments, including open air, screened room, chambered, and conducted (in which antennas are replaced with cables), and he describes near- and far-field regions within an anechoic chamber.

In consecutive chapters on physical-layer and protocol tests, he takes readers through the gamut of test types, ranging from functional tests that occur during development to compliance tests that determine whether a product meets IEEE specs as well as government-mandated emissions requirements. In the physical-layer chapter, he provide such details as how a constellation diagram represents error-vector magnitude; the protocol-test chapter covers transport-layer, network-layer, and data-link-layer test.

Additional chapters cover topics including application-level measurements (including voice over WLAN, or VoWLAN, test), manufacturing test, and multiple-input multiple-output (MIMO) test. An appendix provides a helpful list of relevant standards and organizations. (Note: The publisher is owned by Test & Measurement World's parent company.)