Track Timing (802.16 OFDM)

Default: Cleared (See 802.16 OFDM Standard Setups/Presets Table.)

Track Timing specifies whether the VSA tracks timing changes in the pilot subcarriers.

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. performs demodulation relative to the data in pilot carriers embedded in the signal. These pilot carriers replace data-carrying elements of the signal and allow some kinds of impairments to be removed or "tracked out."

Many impairments will be common to all pilot carriers, and can be measured and displayed as "common pilot error."

In addition, several specific tracking functions can be individually switched on and off in the demodulation performed by the VSA. This is a very useful troubleshooting approach, since modulation errors can be examined with and without the benefit of particular types of pilot tracking.

When Track Timing is selected the VSA applies pilot subcarrier timing error correction (frequency offset correction) to the pilot and data subcarriers. This is in addition to Track Amplitude and Track Phase error correction if selected.