Methods Used In Transceiver Front-end For Full Duplex Communication

With the rapid development of wireless network communication and the increasein wireless network connected business, wireless spectrum became more and morecrowded. Therefore, people want to pursuit improvement in the transmission rate andtransmission reliability without adding extra frequency. Nowdays, wirelesscommunication systems are designed in half-duplex model, by the technology of timedivision duplex or frequency division duplex. However, these technologies have defects:they somehow either sacrificing efficiency or sacrificing spectrum in realization.Traditionally, it is impossible to suppose terminal can send and receive at the same timewith one certain frequency, because the transmitted signal on the receiving end willcause a very strong self-interference and led directly to the receiver can not extract theuseful signal. This paper will introduce a new wireless communication structure whichican accomplish the full-duplex structure. And this paper also explores availabletransceiver RF front-end technology to improve the capacity and performance ofwireless communication systems.Firstly, this paper gives the analysis of wireless network communication systemand briefly describes the current academic development and the wireless networkcommunication system’s history of development. In the third chapter, this paper focuseson the isolation of the antenna. Then this paper discuses the feasibility in realizing theantenna polarization isolation technology in full-duplex system, and gives example indesigning both single frequency and dual frequency in transceiver antenna toaccomplish the high isolation. In order to reduce the self-interference signal futher andincrease of the reliability of full-duplex communication system, in the fourth chapter,this paper discusses the principle of vector modulation based RF cancellationtechnology. And then gives the analysis in RF cancellation under the multipath effect.Then, this paper uses QHx220chip to design hardware circuits, and finishes circuitdebugging. In the fifth chapter, in order to test the feasibility of the two techniques, andverify the improvement of full-duplex as well, this paper gives the test results about a system accompanied by single frequency antenna and RF cancellation module. Furthermore, this paper gives the analyzation in802.11b-based communication system: itmakes a research on the feasibility of popularizing and channel capacitance infull-duplex communication Then, this paper discusses present the opinion that hiddenterminal and exposed terminal in WLAN network can be well sloved in full duplexcommunication.In the last chapter, this paper gives a summary of the above content, and analysethe defects and deficiencies in the RF front-end in full-duplex communication system.Last but not least, this paper sums the lessons gained in the course of the study, and putup the future work and direction.