Performance Analysis of E-band 12-Kilometer Long Transmission Links Based on Experimental Data

Recent advances in millimeter wave (mm-wave) technologies have inspired various communications exploiting the large spectrum resources. Among which, the E-band, i.e., the 71-76 and 81-86 GHz frequency bands, has an ultra-wide bandwidth of 10 GHz and can potentially provide tens of Gigabits-per-second (Gbps) data rates. The E-band mm-wave is thus considered a candidate for building high-capacity wireless backhauls, especially in long-range transmission scenarios. In order to evaluate E-band link performance in real propagation environments, we conducted several outdoor experiments. Here we report one experiment across a salt lake in Qinghai Province of China, and another across the sea near Sanya Bay of South China Sea, both having a line-of-sight (LOS) path distance of around 12 km. An E-band system with highly-directive and dual-polarized Cassegrain antennas, operating at a center frequency of 74 GHz and supporting a signal bandwidth up to 1 GHz, was used. Signals with different modulation schemes and symbol rates were transmitted through the long-range channels and finally recorded at the receiver side. Based on the obtained data, we analyze E-band link performance. The results show that 2-2.5 Gbps uncoded data rates can be achieved with relatively low bit error rates (BERs) by using 16- and 32-QAM in co-polarized single-input single-output (SISO) links. When higher-order modulation schemes are used, BERs increase accordingly. The 64-QAM transmission provides a maximum data rate of 3 Gbps but has a BER of 10
^-1
. This work indicates that an E-band long-range SISO link can achieve a multiple-Gbps data rate over a below 1-GHz bandwidth, and by using multiple-antenna technologies, there is a potential of boosting data rates to reach tens of Gbps. Hence, we foresee that E-band mm-wave can replace fiber optics in various long-distance backhaul scenarios.