Chapter 3 - WLAN test environments

Abstract

This chapter discusses the different WLAN test environments and their characteristics. Wireless LAN (WLAN) equipment is tested in various types of environments, including open-air, chambered, or conducted. WLAN performance, on the other hand, is significantly affected by changes in the environment. It is necessary to consider the physical environment surrounding the equipment being tested as part of the test setup, and to incorporate its characteristics into the test methodology, in order to successfully test WLAN equipment. Open-air environments use the actual physical surroundings in which the WLAN equipment will be deployed. Conducted setups are used for the majority of all WLAN testing, from low-level RF measurements to application layer performance measurements. They are reasonably low-cost, easy to set up and use, compact, and flexible. Distances in the real world can be emulated using attenuators or power level control. Channel characteristics can even be emulated, somewhat expensively, using channel simulators. It is found that a key parameter in most over-the-air test scenarios is the diameter of the first Fresnel zone between the transmitter and receiver. It is observed that measurement repeatability is significantly affected by the type of environment chosen to conduct wireless testing, as well as the usual factors in any type of network testing.