MIMO-OFDM systems aim to improve transmission quality and/or throughput but require significant signal processing capability and flexibility at reasonable cost. This paper proposes a reconfigurable architecture and associated algorithm optimizations for these types of systems based on the IEEE 802.11n and IEEE 802.16e standards. In particular, we describe the implementation of two key computations onto this architecture, namely Fast Fourier Transform (FFT) and Space-Time Block Decoding (STBD). The design is post-layout using a UMC 0.18 micron technology at a clock rate of 100 MHz. Performance comparisons with other optimization methods and hardware implementations are given.