Calculating Phase Noise Margins for Industrial Wi-Fi Seven Modules Operating near Arc Welders
Phase noise margin calculations near arc welders demand adding reciprocal mixing degradation figures directly to local oscillator phase noise floors.
Subcarrier Spacing
Meaning
Frequency interval between adjacent orthogonal carriers defines the fundamental structure of an orthogonal frequency division multiplexing signal. Optimal subcarrier spacing is determined by the expected mobility of the device and the characteristics of the radio channel.
Waveform Numerology
Scaling the width of the carriers allows the system to adapt to different frequency bands and deployment scenarios. While a wider subcarrier spacing provides better resistance to phase noise and doppler shift, it also results in a shorter symbol duration. This flexibility enables the use of the same basic waveform in both sub-6 GHz and millimeter wave spectrum.
Propagation Environment
Selecting the correct interval is necessary to balance the effects of delay spread and frequency selectivity in the radio path. In environments with many reflections, a narrower subcarrier spacing can help mitigate the impact of multipath interference by allowing for longer guard intervals. The choice of spacing directly affects the ability of the receiver to synchronize with the transmitted signal.
Hardware Complexity
Managing the trade off between subcarrier density and processing overhead is a primary focus during the hardware design of the baseband processor. High density signals with narrow subcarrier spacing require more complex fast fourier transform operations and increased memory. The sampling rate and clock stability requirements of the radio module are dictated by the chosen waveform configuration.