E-Band Propagation Measurements and Initial Analysis for Long-Range Communication Over Sea

Wireless backhaul over sea requires long-range and high-speed transmissions. To achieve this, a promising technology is the E-band millimeter-wave (mm-wave) communication. However, E-band long-range propagation can be largely affected by over-sea environments and meteorological conditions. In the paper, we report an experimental study on 74 GHz mm-wave propagation of around 12.2 km distance over sea. Based on 4-day measurements across the sea near Sanya Bay, China, we provide initial analysis of propagation characteristics in terms of average received power, received power variation, cross-polarization ratio (XPR), and how they are affected by meteorological conditions. Results show that the amount of water vapor in the atmosphere affects signal power attenuation. The higher the absolute humidity, the lower the received signal power. In a short time of 30 s, the received power variation can be as high as 10 dB and seems related to wind speed. It is also observed that vertically-polarized waves have considerably less attenuation than horizontally-polarized waves. The research gives a preliminary insight into E-band long-range propagation properties in over-sea environments.