Subblock Processing for Frequency-Domain Turbo Equalization Under Fast Fading Environments

Abstract

SUMMARYFrequency-domain equalization (FDE) has been studied for suppressing inter-symbol interference (ISI) due to frequency selective fading in single carrier systems. When a high-mobility terminal is assumed in the system, channel transition within an FDE block cannot be ignored. The ISI reduction performance of FDE degrades since the cyclicity of the channel matrix is lost. To solve this problem, a method of dividing the received data block into multiple subblocks has been proposed, where pseudo cyclic prefix (CP) processing is introduced to realize periodicity in each subblock. In this method, the performance is degraded by the inherentlyinaccurate pseudo CP. In this paper, we study the application of frequencydomain turbo equalization (FDTE) to subblock processing for improving the accuracy of pseudo CP. The simulation results show that FDTE with subblock processing yields remarkable performance improvements. key words: fast fading, single carrier transmission, SC/MMSE-FDTE, unique word, subblock processing

2-Step Frequency-Domain Channel Estimation for Training Sequence Inserted Single-Carrier Block Transmission

“…For MMSE-FDE, accurate estimation of channel transfer function is necessary. Some studies on channel estimation for training sequence inserted SC (TS-SC) block transmissions are found in [5,[7][8]. By using a training sequence of length equal to 2L symbols, where L denotes the channel length, the channel can be estimated by exploiting the circular property of the training sequence.…”