ICI CANCELLATION IN OFDM SYSTEMS IN PRESENCE OF PHASE NOISE AND TIME VARYING CHANNELS

Abstract

The ever-increasing demand for very high-rate wireless data transmission calls for technologies which make use of the available electromagnetic resource in most intelligent way. Key objectives are spectrum efficiency, robustness against multipath propagation, range, power consumption, and implementation complexity. These objectives are often conflicting, so techniques and implementations are sought which offer the best possible tradeoff between them. Two of the most effective means of closing the gap between the achieved performance and channel capacity are advanced channel coding and Orthogonal Frequency Division Multiplexing (OFDM). In conjunction with advanced forward error correction coding, advanced OFDM is the modulation of choice when it comes to improving robustness against multipath fading at reasonable cost of implementation. Therefore, the OFDM has been adopted as a standard in terrestrial digital broadcasting and wireless local area networks. OFDM still faces challenges like Inter-carrier Interference (ICI), and Peak to Average Power Ratio (PAPR). In this thesis work, causes of ICI, different ICI cancellation methods are discussed. Performance evaluation of ICI self cancellation methods is done. In case of multipath channels low complexity ICI matrix estimation and equalization technique is implemented, and its performance evaluation is carried out.