Space division multiplexing of 120-GHz-band wireless links using high-gain antennas

This paper investigates space division multiplexing in a 120-GHz wireless link system for frequency reuse. The 120-GHz-band wireless equipment employs high-gain antennas, and the 120-GHz-band millimeter-waves travel straight. Therefore, the interference between two wireless links using the same frequency is expected to be small, even when two wireless links are set close to each other. When two links transmit 10-Gbit/s data signal in the same direction over a distance of 800 m, a bit error rate (BER) of below 10^-12 is obtained when the receivers are set 30 m apart, and polarization multiplexing makes it possible to further reduce the separation distance. When two links transmit 10-Gbit/s signal in opposite directions, interference between the two links hardly occurs when they are set within 2 m. We have also succeeded in achieving a bi- directional wireless connection of a 10Gigabit Ethernet link.