Channel characterization of mobile radio channel over sea at 2 GHz

Maritime communication has been considered as a core issues in the marine activities. However, few wideband wireless communication systems have been carefully evaluated for maritime applications due to a.o. insufficient knowledge of radio channel characteristics over sea. Therefore, a land-to-ship (L2S) radio channel measurement assignment has been performed in Trondheim, Norway. In this paper, we have focused on the open sea propagation environments and results of the channel characterization from measurements are presented, such as path-loss, channel correlation and reflections from the sea surface. We have compared the received signal level (RSL) with the Okumura-Hata model, the COST 231-Hata model and the ITU-R P.1546-2 model, and it has been found that the ITU-R model for open cold sea corresponding to field-strength value exceeded at 50% of the locations fits the measurement results best. By using two receiver antennas with 1.85 meters spacing, partly channel correlation has been revealed when the distance between the transmitter (TX) and receiver (RX) is within 2 km, while the two channels are found to be highly correlated when the boat is far away from the shore. Finally, reflections from the sea surface are found to be rather small over the open sea and the fading mainly due to sea reflections have been observed to be maximum 2 dB with a standard deviation of 0.5 dB. Closer to land this was different.