Investigations On TDD RF Receiver System Of B3G Access Point

When the 3rd Generation Mobile Communication technology is grown up and will soon be put into the markets, scientists have begun to do some research in the next generation, that is Beyond 3G/4G mobile communication technology and some countries and organizations set about to establish the standard for it. China has designed and started the plan named Future Technologies for Universal Radio Environment for the research of the next generation mobile communication.Because of rapidly increasing high-speed data and wideband Internet services, future mobile communication system need more capacity and higher transmission rate. MIMO(Multiple Input Multiple Output) technique employs multiple transmitting antennas and multiple receiving antennas simultaneously, which can utilize space diversity effect, restrain multi-path fading and greatly increase the capacity and spectrum efficiency of a wireless communication system. MIMO technology will possible become a key technology in the next generation mobile communication.According to the requirements of the"863"key project:"Research and Development for FDD/TDD RF system and Antenna Array", this paper focuses on the research of the RF receiver for the B3G communication system. First introduces the whole RF system, including system specification, duplex method, key technology, interface definition and etc. Second, discusses a kind of receiver plans and then the simulation for system have been done. The receiver used in TDD RF system working at 3.45GHz, adopts superheterodyne plan. It has four channels and each channel is composed of remote receiver and local receiver. Remote receiver includes the bandpass filter mixer, amplifier and RF LO. Local receiver consists of the T/R switch, RSSI part, gain control part, quadrature demodulater, baseband unit and IF LO. In chapter 4, main functions and characters of the each part of the circuits are described in detail. Finally the circuits are implemented and the test results indicate that the receiver can satisfy the requirement.