Low Signal-to-noise Ratio Of Two-dimensional Spread Spectrum Wireless Transceiver Design

Spread spectrum technology is widely used in military anti-jamming systems andmobile communication systems for its advantages of good anti-interferenceperformance, excellent quality of concealment, little interference, easy to realize thecode division through multiple access and digital-to-analog compatibility, etc. In recentyears, on the basis of spread spectrum technology, two-dimensional spread spectrumtechnology that can spread spectrum in the time domain and frequency domain at thesame time has been extensively studied, which is the further development of traditionaltime-domain direct sequence spread spectrum (DSSS) and multi-carrier code divisionmultiple access spread spectrum (MC-CDMA).For the wireless transceiver is used increasingly widely, it is of great significance toimprove its performance in the anti-jamming and low signal to noise ratio environment.Therefore, on the basis of the two-dimensional spread spectrum technology, the designof the low signal to noise ratio two-dimensional spread spectrum wireless transceiver ismeaningful.To begin with, this paper has made demand analysis of the low signal to noise ratiotwo-dimensional spread spectrum wireless transceiver, calculating the budget for thecommunication link, analyzing the possibility of the designed specifications, outliningstructure of the transmitter and receiver, its specific functional requirements,performance requirements and environmental requirements and setting the goal for theoverall design.In the second place, this paper provides an overall design of the low signal to noiseratio two-dimensional spread spectrum wireless transceiver, dividing the transmitter intothe voice processing module, the signal processing module and the RF processingmodule. At the same time, the related receiver is also divided into the RF processingmodule, signal processing modules and voice processing module. At the same time, adetailed function and interface design have made for each module.Furthermore, the paper introduces the FPGA information process part of the lowsignal-to-noise ratio two-dimensional spread spectrum wireless transceiver. Firstly, theFPGA functional areas is minutely divided and functionalized. Then the wholedevelopment use Xilinx System Generator by modeling and imitating the relatedMATLAB/Simulink tools to complete the corresponding logic function.Finally, this paper finishes the debugging and testing of the low signal-to-noise ratiotwo-dimensional spread spectrum wireless transceiver and analyzes the results of thetest. Besides, having built four test platforms, the working frequency band, thebandwidth, the transmit power and the receiver sensitivity, the wireless communicationdistance as well as the quality of the indoor and outdoor scenes of the communicationhave been tested. The result suggests that the equipment can fulfill all the requirements of the design, that is, under the condition of64×64two-dimensional spread spectrum,the bandwidth of16MHz, the sensitivity of the receiver is116dBm. In addition, under26dBm of transmit power, wireless communication range can be up to50m.The low signal to noise ratio two-dimensional spread spectrum wireless transceiver inthis design is finished and passes the examination of the cooperate partner, havingcreated a great significance on engineering.