Research And Verification Of Enhanced Distributed Antenna RF System

Distributed Antenna System(DAS), as an energy-efficiency way of wireless coverage, has become one of the important directions on wireless communication research. Located in the distal ends, the antenna of traditional DAS which realize the mobile station uplink signal diversity is used to expand the signal coverage. Enhanced Distributed Antenna System, can expand the signal coverage and diversity reception, as well as improve the communication system capacity by using spatial multiplexing. A 2T2 R MIMO DAS downlink RF transmission system is designed in this paper based on 3GPP standards, which supports frequency division transmission in the same cable. The main tasks are as follows:Firstly, the advantages of DAS and corresponding RF transmission systems are analyzed. The investigative directions on DAS are summarized and the advantages and disadvantages of each RF system are discussed. According to the 3GPP standard, main technical parameters such as gain, output power, spurious and linearity of proximal and distal ends are analyzed. The technical specifications are also given.Secondly, the enhanced DAS RF system is designed in the paper. The proximal and distal ends’ plan which includes RF channels and LO circuits is built based on the function of the RF system. Configurations of each channel in proximal and distal ends are designed, and the LO output circuit in proximal ends and LO detected circuit in distal ends are analyzed. Further more, the control scheme is determined.Thirdly, certain devices are selected to complete the hardware implementation according to the RF system,to ensure the main parameters of the circuit meet the requirement. Suitable external circuits should be added to each device to make sure the device is in good performance.Finally, the proximal and distal ends are debugged, and the main functions and technical specifications are tested. Each channel in proximal and distal ends are tested and verified to meet the functional requirements. The downlink signal RF transmission system which composed of proximal and distal ends is verified to achieve 2T2 R MIMO downlink channel capacity.A 2T2 R MIMO DAS downlink RF transmission system is designed and verified in this thesis, which can be used as a hardware platform for Enhanced DAS channel capacity-related research. It also promotes a further development of DAS.