LTE technology is a technology taking Orthogonal Frequency Division Multiplexing (OFDM)/Frequency Division Multiplexing Access (FDMA) as a core, and it is considered as a quasi-4G technology. Being compared with the 2G/3G technology, the LTE technology has advantages of providing a higher data rate, increasing cell capacity, reducing a system delay, supporting larger cell coverage and the like, so the LTE technology is increasingly favoured by communication operators, and its application range is extended from high-speed train communication to ground-to-air communication, for example, an aircraft communication system which enables passengers to enjoy data services on the flight.
At present, low-altitude communication airline coverage of the LTE is shown in FIG. 1; a ground-to-air wireless channel is established by using an LTE evolved Node B (eNB) 10 for network layout along an airline, and taking an LTE User Equipment (UE) 20 as mechanical communication equipment (airborne LTE UE). The network layout of the LTE in a cabin is shown in FIG. 2; after establishing a connection with the LTE eNB through an external antenna 30, the airborne LTE UE connects a Wireless Fidelity (WiFi) Access Point (AP) 40 through an Ethernet in the cabin to build a wireless local area network, the passengers on the plane can use a smart phone, a Personal Digital Assistant (PDA), a portable computer and other devices to access to the wireless local area network, so as to realize services of surfing the Internet, receiving and sending emails, File Transfer Protocol (FTP) download and the like.
External antenna distribution of an airplane is shown in FIG. 3; except the external antenna, a DME device antenna 50 which is necessary for the airplane is also installed at abdomen of the cabin; transmitting power of the DME is 57 dBm, and a downlink frequency point of the airborne LTE UE is just in a range of frequency point occupied by the DME, so when they work at the same time, a Carrier to Interference plus Noise Ratio (CINR) of a downlink channel of the airborne LTE UE is very low, which seriously influences downstream traffic of the LTE system. Because of being interfered, a subframe interfered by the DME will be retransmitted for many times because it cannot be validated; however, even the same Hybrid Automatic Repeat Request (HARQ) is retransmitted for many times, process data may still not be validated by a Cyclic Redundancy Check (CRC); thus, invalid retransmission of many times will waste wireless resources, and combination failure of many times will influence a Modulation and Coding Scheme (MCS) value of the LTE eNB scheduling the subsequent subframe, which causes a drop of the downstream traffic of the LTE system.
USPTO Backgrounds
USPTO Backgrounds