LOW COMPLEXITY ITERATIVE RECEIVER DESIGN FOR OFDM SYSTEMS

Abstract

OF THE DISSERTATION Low Complexity Iterative Receiver Design for OFDM Systems By Vamadevan Namboodiri Advisor: Prof. Predrag Spasojevic Single Input Single Output (SISO) Orthogonal Frequency Division Multiplexing (OFDM) systems have been adopted in many of the recent wireless communication standards such as European terrestrial broadcast systems based on DVB-H, DVB-T, DVB-T2. For OFDM systems, cyclic prefix of sufficient length makes the receiver design simple in frequency-selective multipath environments. Wireless communication based on Multiple Input Multiple Output (MIMO) systems has also gained popularity due to the potential capacity increases it can provide. MIMO-OFDM based transmission systems can thus provide very high data rates with a relatively simple receiver design and are now adopted widely in recent wireless communication standards such as Long Term Evolution(LTE), LTE Advanced, WiMAX and WiFi. Modern wireless communication applications, both SISO and MIMO, require high data rates in a limited bandwidth at high carrier frequencies and at high levels of mobility. This results in less intercarrier spacing and severe time-varying frequency-selective multipath fading, which breaks the orthogonality of subcarriers and causes intercarrier interference (ICI) in the received signal thus severely impacting the BER performance of the receiver. In the trend of adopting higher carrier frequencies, higher bandwidth and higher mobility, ICI is expected to be more of a limiting factor in mobile OFDM systems. Therefore efficient