Microwave Engineering Europe - April 2008 - (Page 16)

16 TEST & MEASUREMENT be done with an engineering bench top set-up that uses RF isolated enclosures for the devices under test coupled with a well designed channel emulator. Such set-ups can replace the need for costly screen rooms or standard test house environments which lack repeatability across multiple locations. Test complexity demands automated channel emulation test systems The need to run time-consuming, statistically signiﬁcant tests with a channel emulator has been discussed. That, coupled with the need to run several models as well as the need to adjust parameters like range (of the client device from the base station) and motion, results in many hours or days of testing effort. Without a completely automated test environment, engineers either need to be physically present or at least log in frequently to the test set-up to make all the necessary changes. By using a channel emulator that is completely coupled to a test automation environment, which not only controls the emulator, but can also command and control the base station and clients, many tests can be batched up and run without human intervention. Test automation systems that automatically store the results in a database, with appropriate timestamps and product information, provide a complete record of the testing performed. They also provide a basis for comparing test results as system hardware/ software is changed, or alternate devices are tested. Such automated testing improves time to market, test coverage, repeatability and the collection as well as archival of the results. Cost-effective and easy-to-use channel emulation test systems require system integration The cost of ownership for a channel emulator includes the cost of the procurement, installation, usage and maintenance of the entire channel emulation test system. Channel emulation test systems that require complicated off-site integration and calibration of the channel emulator and controlled RF environment can be costly to purchase and maintain, suffer signiﬁcant time delays in the lead up to operational status as well as periodic down-time for required recalibration. A turnkey solution that integrates the channel emulator, controlled RF environment, Table 3. Summary of critical technical and use requirements for channel emulation of WiMAX and Wi-Fi devices. test automation software and test results database can signiﬁcantly reduce installation and ongoing costs. In addition, a single console that controls device conﬁguration, test equipment, test execution and output make operation simple and efﬁcient for the user. Summary The complexity of WiMAX and Wi-Fi technologies, particularly those employing MIMO, as well as the performance and interoperability demands of voice and video applications is driving the need for comprehensive testing of WiMAX and Wi-Fi devices. Channel emulation enables vendors and service providers to test devices using recreated, real-world channel conditions, thus minimizing the time and expense of testing in the “actual” real-world. Technical speciﬁcations are a critical consideration in choosing a channel emulator. To accurately re-create the over-the-air conditions of the real-world, a channel emulator must be dynamic and bi-directional with a phase balanced reciprocal channel calibration. The noise performance of an emulator must be better than the device under test, and the noise ﬂoor must be low. In addition, a 4x4 MIMO capable channel emulator is required. Channel emulators also vary in the efﬁciency with which they can be used. Features such as sophisticated channel model control as well as seamless integration with a controlled RF test environment, system level test automation and a results management database, all help to optimize the effectiveness of a channel emulator as an engineering tool. In selecting a channel emulator, engineers should look for the combination of technical speciﬁcations and end-user features that meet the demanding requirements of their new WiMAX and Wi-Fi product designs. Table 3 summarizes the critical technical and use requirements for channel emulation of WiMAX and Wi-Fi devices along with the corresponding channel emulator or test system feature that addresses each requirement. About Azimuth Systems Azimuth Systems is a leading provider of wireless data communications test solutions. Azimuth’s products are used by the world’s foremost wireless semiconductor, system vendors and service providers to speed timeto-market and improve wireless product quality. The company offers the ACE™ 400NB channel emulator for Wi-Fi product testing and the ACE 400WB channel emulator for WiMAX product testing. Both platforms are purpose-built MIMO channel emulators, designed to meet the critical technical and ease-of-use requirements for engineers choosing a channel emulator. MICROWAVE ENGINEERING EUROPE Free subscription at: www.mwee.com/subscribe Microwave Engineering Europe ● April 2008 ● www.mwee.com 011-012-014-016_MWEE.indd 16 26/03/08 17:57:12 http://www.mwee.com/subscribe http://www.mwee.com

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Microwave Engineering Europe - April 2008 News Contents Comment Test and Measurement: Comprehensive WiMAX and Wi-Fi Product Design Demands Effective Channel Emulation Military/Aerospace Focus: Hardware Needs Limit Software Radio Interview — Mitsubishi Electric Europe: GaAs Technologies Spanning High-End Space and Radar Through to Cost-Sensitive Handset and LNB Applications How Do You Test ZigBee Transmitters? Advanced Receiver Design Boosts Performance CMOS PAs Pave the Way for One-Chip Phones Products Calendar

Microwave Engineering Europe - April 2008

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