Effect of Carrier Frequency Offset on the Channel Capacity in Multiuser OFDM-FDMA Systems

the opportunity of a detailed link adaptation scheme. The combination of these transmission-and multiple access techniques in OFDM-FDMA is an ideal and very strong candidate for the downlink of future 4G mobile communication systems. This technical combination offers high cell capacities by exploiting the inherent multi user diversity effect of the system. To apply OFDM-FDMA in the uplink, the time and carrier synchronization accuracy becomes very important. Non-ideal synchronization of the user signals to the carrier frequency of the base station leads to intercarrier interferences (ICI). In this paper, an analytical model for the ICI consideration in the uplink of a multi user OFDM-FDMA based system is derived. The impact of the carrier frequency offset (CFO) on the performance of a cellular multi user system with respect to different subcarrier allocation schemes is analyzed.