Setting the Center Frequency (802.16 OFDMA)

For OFDMA signals, the analyzer's center frequency must be set within the carrier lock range of the transmitted carrier frequency to achieve carrier lock. The carrier lock range of the VSA varies depending on the signal BW, BW Ratio, FFT Fast Fourier Transform: A mathematical operation performed on a time-domain signal to yield the individual spectral components that constitute the signal. See Spectrum. Size, Subframe Type, and Zone Type as described below:

Downlink subframe carrier lock range:

All zone types:    Carrier Frequency +/- 4.5*SubcarrierSpacing

Uplink subframe carrier lock range:

PUSC partial usage of subchannels: Some of the subchannels are allocated to the transmitter., OPUSC zones: Carrier Frequency +/-1.5*SubcarrierSpacing

AMC Adaptive Modulation and Coding zone:    Carrier Frequency +/-4.5*SubcarrierSpacing

Example frequency lock range calculation

Signal characteristics: BW = 8.75 MHz Megahertz: A unit of frequency equal to one million hertz or cycles per second., BWRatio = 8/7, and FFTSize = 1024

Using these parameters in the following equation

SubcarrierSpacing = BW*BWRatio/FFTSize

The subframe carrier lock ranges are:

Downlink subframe:

All zone types: ~ +/- 43 kHz kiloHertz: A radio frequency measurement (one kilohertz = one thousand cycles per second). of the Carrier Frequency

Uplink subframe:

PUSC, OPUSC: ~ +/-14 kHz of the Carrier Frequency

AMC:   ~ +/- 43 kHz of the Carrier Frequency

See Also

Available Features (802.16 OFDMA)

About Option B7Y IEEE 802.16 OFDMA Modulation Analysis

Selecting the 802.16 Demodulator

Using a Standard Setup (802.16 OFDMA)

Troubleshooting (802.16 OFDMA)