Frequency Domain Probabilistic Data Association Equalizer for OFDM Systems Without Cyclic-Prefix

In this paper we use probabilistic data association (PDA) equalizer in OFDM signal without cyclic prefix (CP) to remove intersymbol interference (ISI) and intercarrier interference (ICI) in the frequency domain. In order to cancel out the ISI and ICI in OFDM systems, CP with a length longer than the channel length is used. However, this causes performance degradation due to increased required bandwidth, hence, a lower bit rate, and uncalled for power utilization in the OFDM transmitter for CP. Research on reducing or even cancelling out the CP in the transmitter has focused on using bandlimiting filters in time domain. We use probabilistic data association (PDA) strategy to equalize for ISI and ICI effects in the frequency domain by considering them both as a Gaussian process in each subcarrier to cancel their effect without any noise enhancement.