Phase Noise Induced Intercarrier Interference in Multiuser OFDM Systems

L. Haering, S. Bieder, A. Czylwik, and M. Speth (Germany)


OFDM, Phase noise, Intercarrier interference, SDMA


In this paper, an analytical derivation of phase noise driven intercarrier interference (ICI) power in space division multiple access (SDMA) orthogonal frequency division multiplexing (ODFM) systems is presented. In low cost ap plications like e.g. wireless local area networks (WLAN), cheap oscillators will be used which exhibits distinct non idealities like carrier frequency shifts and phase noise. It is well-known that especially multicarrier systems like OFDM suffer from a high sensitivity to these oscillator imperfections since ICI occurs. In comparison with fre quency offsets, the compensation of phase noise effects is much more intricate due to its random nature and usu ally, considerable ICI remains in practical systems. Un der the assumption of a Lorentzian power spectral density (PSD) of the oscillators' phase noise, the amount of perfor mance degradation due to ICI in terms of loss in signal-to interference power ratio (SIR) is calculated in this contribu tion. A multiuser uplink scenario is considered in which the multi-access scheme SDMA is used to differentiate miscel laneous users. It turns out that multiple phase noise terms from different users give rise to increase the ICI power lin early with the number of users.

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