TV White Spaces (hereinafter referred to as the "TVWS") is the radio spectrum has not been used, is assigned to using in broadcast television. TVWS has the advantages of high transmission distance, strong penetrating ability, not easy to be absorbed by water, large amount of transmission unit data, etc., low spectrum occupancy rate in maritime, is very suitable for maritime wireless network coverage. In this paper, the maritime communication system based on TVWS uses the wireless mesh network as the network architecture. Communication access point(hereinafter referred to as the "AP") based on the software router system (hereinafter referred to as the "ROS"). TVWS is used as the distance communication spectrum between APs. The AP implements the data exchange between WIFI and TVWS, and provides Ethernet wired access and WIFI wireless access for the terminal equipment. The communication system uses the Socket transmission protocol to set up the end to the end connection, realizes the functions of GPS, character communication, picture transmission, audio communication, video communication and camera monitoring, etc., using H264 video compression format to achieve smooth video communication.
IntroductionIn current, communication devices in the sea using a single sideband shortwave radio, very high frequency(VHF) wireless phone, ultrashort wave(USW) interphone, cellular phones, satellite phones and other. These communication methods have advantages and disadvantages: the principle of the single sideband shortwave radio communication is reflected by the atmosphere. It has long communication distance, has lower costs than satellite phone, is terminal equipment maintenance is convenient. But this way has communication cover blind area, vulnerable to interference like weather, low confidentiality; VHF wireless phones can communicate about 20 nautical miles and only for the ship to shore and ship between voice communication; USW interphone is mainly used for voice communication at close range between the ships, unable to realize broadband communication; cellular handset communication costs low, but cellular base station signal coverage distance is limited, usually only in the offshore available. At present, commercial fishing, shipping, emergency rescue, or coast guard communications are based on the satellite and deploy mesh network in maritime [1]. For ship and land communication, the ship carrying mobile terminal is connected to the maritime wireless mesh network first, and then through the ship borne satellite gateway access satellite mobile network [2]. The satellite mobile communication is suitable for the ocean shipping, but the terminal configuration, maintenance and communication costs are relatively high. Small and medium vessels at sea are often unable to buy such expensive satellite communications and navigation equipment. In order to integrate the heterogeneous wireless and wired networks, people proposed that the different paths of the ship and the ship, the ship and the land traverse through the VoIP system. ...