A High-Speed Four-Transmitter Four-Receiver MIMO OFDM Testbed: Experimental Results and Analyses

By adopting multiple-input multiple-output (MIMO) and orthogonal frequency-division multiplexing (OFDM) technologies, indoor wireless systems could reach data rates up to several hundreds of Mbits/s and achieve spectral efficiencies of several tens of bits/Hz/s, which are unattainable for conventional single-input single-output systems. The enhancements of data rate and spectral efficiency come from the fact that MIMO and OFDM schemes are indeed parallel transmission technologies in the space and frequency domains, respectively. To validate the functionality and feasibility of MIMO and OFDM technologies, we set up a fourtransmitter four-receiver OFDM testbed in a typical indoor environment, which achieves a peak data rate of 525Mbits/s and a spectral efficiency of 19.2 bits/Hz/s. The performances including MIMO channel characteristics, bit-error rate against signal-tonoise ratio curves, the impairments of carrier frequency offset and channel estimation inaccuracy, and an asymmetric MIMO scheme are reported and analyzed in this paper.