About 802.16 OFDM Modulation Analysis

89601B7RC (89601B-B7S/B7Y) adds 802.16 OFDM Orthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS. modulation analysis for IEEE Institute of Electrical and Electronics Engineers. A US-based membership organisation that includes engineers, scientists, and students in electronics and related fields. The IEEE developed the 802 series wired and wireless LAN standards. Visit the IEEE at http://www.ieee.org 802.16a-2003 and IEEE 802.16-2004 broadband wireless access standard signals to your 89600 VSA software. The specifications for these signals are documented in the IEEE 802.16a-2003 and IEEE 802.16-2004 standards. IEEE 802.16 OFDM signals are also known as WiMAX signals, an acronym for "Worldwide Interoperability for Microwave Access", a standards-based wireless technology that provides high-throughput broadband connections over long distances.

While providing demodulation capabilities for standard 802.16 OFDM formats, 89601B7RC also provides the flexibility to measure nonstandard OFDM formats. The VSA's demodulator parameters are user-definable, providing the ability to customize the VSA to measure non-ideal signals. User-definable parameters include Data Subcarrier Modulation Format, Nominal Bandwidth, Manual FS/BW Ratio and Guard Interval (see IEEE 802.16 OFDM Demod Properties dialog box).

Configure the VSA to measure 802.16 OFDM through MeasSetup > Measurement Type > Broadband Wireless Access. Signal locking requires these parameters to be set properly: Center Frequency, Guard Interval, Nominal Bandwidth, and Search Length.

Along with the typical digital demodulation measurement results, several additional 802.16 OFDM unique trace data formats and numeric error data results enhance data analysis. These include Error Vector Time, Error Vector Spectrum, Common Pilot Error, RMS Error Vector Time, Subframe Info and RMS Error Vector Spectrum trace data (see Available Trace Data (802.16 OFDM)). Flexible trace data scaling and marker functionality help make accurate and quick measurements.

It is possible to display measurement data for only one 802.16 OFDM subcarrier at a time (using the Subcarrier Selection parameter) or for selected data regions (using the Measurement Interval and Measurement Offset parameters). These features provide a tremendous tool for signal analysis and troubleshooting (see Result Length Parameters).

The VSA uses the measured signal (called IQ Meas) to generate an ideal signal (called IQ Ref). Many IQ Meas and IQ Ref trace data formats and numeric error trace data are computed and available for data display and analysis. This data can be used to quantify and locate errors in the signal, see About Symbol Table.