Research On Terahertz Wireless Communication System And Baseband Design

Due to the high orientation of terahertz wave and the high bandwidth of terahertz band,terahertz communication technology has a strong potential application value in broadband wireless communication and personal area network system.Through the study of the propagation of terahertz waves in the atmosphere,it can be found that there is a transmission window for the terahertz wave,which is about 200-300 GHz.However,it has to overcome many serious technical hurdles to obtain a viable terahertz communication solution.Firstly,because of high orientation of terahertz wave,how to find an alternative path,when there are obstacles(such as: people,vehicles)temporarily block between the transmitter and receiver which are transmitting data,is an urgent problem.Secondly,the terahertz wireless data link is different from today's indoor wireless communication system.The realization of indoor terahertz communication system is not only the extension of existing technology,but also must integrate many new ideas.In this paper,a baseband circuit design for terahertz point-to-point wireless communication is proposed,and a 330 GHz terahertz wireless point-to-point communication system is built on that baseband link.The baseband system is divided into transmitter and receiver.The transmitter is responsible for channel coding,scrambling,adding synchronization sequence,transmitting and so on.The receiver completes analog-to-digital conversion,frame synchronization,descrambling,and channel decoding.At the transmitter,the PC completes the source coding,packing and compression,then transmits the data to the FPGA through the USB2.0 interface.FPGA complete the channel coding which is(2,1,7)convolutional coding,adding synchronization sequence which is refer to the Ga64 and Gb64 sequences in the 802.11 ad protocol.High-speed serial GTX transmitter which is one of IP core of VIRTEX 6 is responsible for transmitting the data.At the receiver,the demodulated baseband signal is sampled by double-rate and 16-bit quantization for analog-to-digital conversion.The 13-bit sampled data is sampled by a 2-rate sampling Golay sequence correlator for frame synchronization,at the same time,by comparing the correlation value from the two sampling signals to select the signal whose SNR is bigger for descrambling and channel decoding((2,1,7)Viterbi decoder with 3bit soft decision).Finally,FPGA transmit the data that complete decoding to PC by USB 2.0.The PC is responsible for decompression,receive packets,source decoding.Finally,the experiment complete a terahertz wireless communication baseband link circuit design and FPGA implementation,its bit error rate is up to 10E-8,50 MHz bandwidth.The baseband can transmit 720 p video by 330 GHz channel whose receiver is 11 m far away from transmitter.