Advanced Equalization Techniques for Channel Estimation in MIMO OFDM System

Abstract

The emerging Fourth Generation (4G) communication supports not only voice communications but also high speed data and multimedia services. Nowadays, multicarrier systems are quickly developing in wireless communication because of high data rate requirements. Orthogonal Frequency Division Multiplexing (OFDM) is a digital modulation method implemented in many wired or wireless communications. The main drawback of multicarrier transmission is signal degradation due to propagation loss that limits its applications. The target of future wireless technology is to provide the effective utilization of higher bandwidth at higher quality of service with efficient transmission technique. The long distance multimedia communication requires large bandwidth and efficient transmission techniques. The Multiple Input Multiple Output (MIMO) technology is introduced with multiple antennas at transmitter and receiver sides to increase the spectral efficiency and for the reliability of the communication. newlineIncreasing spectral efficiency of the wireless communication system is one of the greatest challenges faced by wireless communication engineers. Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing (MIMO-OFDM) verifies to be a better transmission scheme for a wireless application. MIMO-OFDM technology includes increase in diversity and array gain which enhances the coverage area and quality of service of a Wireless Communication System (WCS). Large bandwidth is required for increased data rate and huge number of subscribers in multimedia communications. In MIMO-OFDM receivers there are some imbalance in received signal, which are due to the Intersymbol Interference (ISI) and Intercarrier Interference (ICI). Then ISI and ICI causes reduction in the overall throughput, Bit Error Rate (BER) and increased path loss. newlineChannel estimation in linear system is carried out with conventional Least Square (LS) and Minimum Mean Square Error (MMSE) estimation algorithms. The performance of MIMO-OFDM system is evaluate