Research And Design Of Remote Wireless Bridge

With the development of communication technology, the combination of wired and wireless network plays a powerful role in promoting the progress of society. As a bridge in wireless network, wireless bridge is widely used. It can build the communication network with the advantages of fast, flexible, and efficient, especially in special circumstances(such as natural calamities, emergencies, war, etc). Therefore, it is very important to research the wireless bridge.The wireless work frequency of wireless bridge is focus on two bands(2.4G and 5.8G) for the moment. 2.4G belongs to public frequency band, there are many other wireless devices in the band, and they can interfere with each other, so wireless bridge in 2.4G is usually used in the short distance communication. The electromagnetic wave in 5.8G have a poor diffraction ability and greater transmission loss in the air for high frequency. This thesis comes up with a design proposal of wireless bridge on the basis of researching the principle of wireless bridge and the European Digital Video Broadcasting Terrestrial, using the advantage of DVB-T signal in transmission, combining with the spectrum sensing technology.This scheme adopts digital signal processor as the control core, implementing network data reception and transmission, processing, conversion, and system management, and utilizes the DVB-T for wireless transmission standard. At the same time, uses spectrum sensing technology acquiring idle channel in the UHF TV band, and distributes appropriate channel according to the characteristics of DVB-T system. Ultimately, this solution realizes data transmitting and receiving by wireless, and achieves the function of wireless bridge. The major research and design in this thesis are as follows:1. This thesis analyses the work principle and function demand of wireless bridge, studys network communication architecture and DVB-T system, and puts forward the solution of interconversion between Ethernet data and DVB-T transport stream packet.2. Studying spectrum sensing technology based on primary user transmitter sensing algorithm and primary user receiver sensing algorithm, and comparing the advantages and disadvantages of each sensing algorithm and application situations.3. According to the wireless bridge functional demand, this thesis designs the hardware circuit of the protocol processing conversion module and the idle spectrum sensing module, and completes the hardware debug and software design of the corresponding module4. Designing the control protocol of individual node in a wireless bridge, and control protocol between nodes, realizing the parameter setting and status management of wireless bridge.After the design and debug work in hardware and software of wireless bridge, we tested the duplex communication system with two wireless bridge nodes. The result shows that the wireless bridge system is able to sense the idle channel and realizes wireless data receiving and sending, completes the data transmission in two directions, achieves the anticipated design goal.