Minimum redundancy for FIR equalization in MIMO multicarrier modulation

In this paper, we consider the problem of achieving zero forcing finite impulse response (ZF-FIR) equalization for multiple input multiple output (MIMO) FIR channels in a multicarrier modulation framework. The blocking process inherent in multicarrier modulation results in a block pseudocirculant representation of the MIMO FIR channel. When channel information is available at the transmitter, this block pseudocirculant matrix can be rendered FIR invertible by a suitable precoding operation which introduces redundancy at the transmitter. We derive the expression for the minimum redundancy required to achieve FIR invertibility. It will be seen that the redundancy required is negligible compared to the space-time processing methods, thus supporting higher data rates. Simulation results are provided to demonstrate the effectiveness of the proposed design.