Radio vehicle area network gateway

Abstract

The radio vehicle network gateway is used in coach bus, railway train and other high speed traffic facility. The mobile terminals in the carriages constitute the radio vehicle network. The gateway consists of WPAN module, antenna inside carriage, microprocessor, PCM coding and decoding device, cellular network module, D / A converter, variable gain RF powr amplifier and quarter wave antenna outside the carriage. The microprocessor and PCM coding and decoding device are connected separately with WPAN module and cellular network module; the D / A converter input is connected to the microprocessor; the D / A converter and the cellular network module output is connected the variable gain RF power amplifier; the output end of variable gain RF power amplifier is connected to the quarter wave antenna and RF input end the quarter wave antenna is connected to the cellular network module.

Description

1. Technical field: [0001] The invention is used in high-speed vehicles such as automobiles and trains to make mobile terminals in the carriages form a wireless vehicle area network, and belongs to the technical field of antenna personal area network (WPAN) design. 2. Background technology: [0002] Since the end of the last century, the information industry has maintained a rapid development momentum, especially communication and computer technology, which has penetrated into all walks of life and every corner of people's lives. People expect to be able to communicate with voice and data anytime and anywhere. This requires the use of wireless communication technology. Specifically, it is necessary to use a GSM system or a CDMA system with wide coverage. These systems are ideal for static or quasi-stationary situations, but when the mobile terminal is in the compartment of a high-speed moving car or train, there are factors that affect electromagnetic wave propagation due ...

AI Technical Summary

Problems solved by technology

These systems are ideal for static or quasi-stationary situations, but when the mobile terminal is in the compartment of a high-speed moving car or train, there are factors that affect electromagnetic wave propagation due to the shielding effect of the metal compartment and the Doppler frequency shift. , the communication will encounter the following problems: 1. Due to the weakening of the signal, the mobile terminal will have to increase its transmission power to maintain the communication with the base station. This will increase the power consumption of the mobile terminal and make the use of the battery The time is shortened, on the other hand, the radiation that is too large (about 1 watt) will cause harm to the human body, which is what the user does not want

2. When the signal is weak to a certain extent, even if the mobile terminal transmits with the maximum power, the communication still cannot be carried out normally, which will cause the unreliability or even interruption of the communication

To do so needs to overcome some difficulties such as microwave power self-feedback, and some expensive microwave devices need to be used, so the cost of the equipment is very high, and the function only realizes power amplification, and the overall application cost is too high

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