Increasing Long Range Coverage by Multiple Antennas for Maritime Broadband Communications

Maritime broadband wireless communications differs to typical in-land broadband. The envisaged environment is either open sea or along coastal areas. On the open sea distance between vessel and shore installations have only limited success. However, broadband communication links between vessels or offshore installations are useful. Satellite links are used to overcome the limited terrestrial coverage with a broadband and high data rate link. However, these links suffer from their huge footprints and therefore, only a portion of the overall data rate is reasonable for a single vessel. Further, delays are significant because of the distance to the satellite even between vessels that are close by. Close to the shore the vessels benefit from the cellular mobile radio links that exist anyhow for terrestrial users on land. However, the continuous tremendous increase of data rate over the evolution of the cellular generation from the 2nd (GSM) to the 3rd (UMTS) and now to the 4th generation (LTE) comes with a cost. The main reasons to increase data rate is the densification of cells and the additional used bandwidth per link. Both together decrease the coverage zones on land and therefore, consequently have shrunk the cell sizes for users on the sea. A new broadband solution that guarantees high and reliable data rates with large coverage zones around the shore is needed to cope with the increasing demands on sea. The demand for high data rates increases by novel on sea applications such as tele-health and telematic. In addition recently, marine robots with networking connectivity are essential in environmental sensing and ocean observation applications [1]. Underwater sensors need to bridge the gap between data transmission limits under water and above water. Either remotely controlled or autonomous surface vehicles could perform as that bridge. However, even distant vehicles need the connectivity to assure the received data is delivered timely.