MIMO two-way relaying in frequency selective environment using OFDM

This paper presents Orthogonal Frequency Division Multiplexing (OFDM) based two-way relaying scheme to communicate between two nodes S₁ and S₂ via MIMO Relay Station (RS) in a frequency selective environment. This scheme relies on two-hop relaying approach which uses two orthogonal channel resources to transmit and receive a signal. This scheme requires the channel state information (CSI) only at RS. Spatial filtering is implemented at the RS for transmit and receive processing which is evaluated using zero forcing (ZF) and minimum mean squared error (MMSE) criterion. MATLAB simulations are conducted to evaluate the validity of the algorithm using both criterions in presence of frequency selective environment. The simulation results depict that the algorithm under defined conditions performs better in a frequency selective fading environment with the use of OFDM. Also, the BER performance evaluated through spatial filtering done using MMSE is found to be better than its ZF counterpart.