Spectrum modelling of OFDM signals for WLAN

The orthogonal frequency-division multiplexing (OFDM) modulation format has been adopted in the USA, Europe, and Japan as the standard for wireless local area networks (WLAN), digital broadcasting, and future fourth generation mobile communication (4G). In-band and out-band spectral control requirements in terms of the power spectral density (PSD) of OFDM signals are set in these standards. Presented is the derivation of the PSD of OFDM signals using an IEEE 802.11a example. The accurate analytic expression of the PSD of OFDM signals is very helpful for further OFDM system design in terms of in-band and out-band spectrum regrowth analysis.