INTERFERENCE ALIGNMENT BASED PRECODING FOR ISI MITIGATION IN OFDM WITH INSUFFICIENT CYCLIC PREFIX

Abstract

Interference Alignment (IA) based Channel Independent Precoding for SISO OFDM and MIMO OFDM systems with Insufficient Cyclic Prefix (CP) is proposed that can remove the Inter-Block Interference (IBI) experienced from the insufficient CP with bandwidth efficiency higher than the unprecoded (or conventional) OFDM system with sufficient CP. The BER performance of IA based channel independent precoding in SISO OFDM and MIMO OFDM has been analyzed in comparison to conventional OFDM. The proposed precoding technique is much more bandwidth efficient than the conventional OFDM using the insufficient CP because the IBI caused by the insufficient CP can be set to a subspace whose dimensions are no more than a half of the difference of the length of ISI channel and the length of insufficient CP, so that more information symbols can be sent by using the other half.