Channel Condition and Outage Performance of Mode-Division-Multiplexing Enabled MIMO System With Zero-Forcing Receiver

Reusing the widely deployed multimode fibers (MMFs) in buildings to transmit multiple-input multiple-output (MIMO) signals via mode-division multiplexing (MDM) is an attractive solution to provide low-cost indoor wireless coverage. However, due to the random mode coupling, MMF channel varies over time. In this letter, the MDM-based MMF MIMO channel condition for different fiber lengths is studied. Next, the influence of the fluctuation of channel condition on the outage performance of the MIMO system with zero-forcing receiver is analyzed, in terms of information-theoretic capacity and practical error probability. Finally, by using adaptive coded modulation (according to channel condition), the MDM-based $3 \times 3$ MIMO channel achieves up to 8.62 bit/s/Hz spectral efficiency with 10% outage probability.