Research On Parallel Combined Spread Spectrum Communication Technology In Semiconductor Media

There are many underground work projects in today's society,such as mine exploitation,tunnel construction and subway construction.Once these work accidents,the traditional wired communication way is broken.Rescue workers can't communicate with miners and can't make quick and effective rescue plans.It will miss the best rescue time and bring serious personal injury and huge economic losses.So it is very important to develop a set of emergency communication system which can achieve thorough communication.Because the layered earth is a semi-conductive medium,the system can be realized through current field communication.The designed system also has the advantages of survivability,and so on.At present,most implementations of ground-penetration communication are implemented using common digital receivers.Due to the complex underground environment,there are many interferences in the information transmission process,the system's anti-interference ability is weak,and the information transmission capability is limited.It has the traditional spread spectrum anti-interference ability and secrecy characteristics,and also has a high frequency band utilization and information transmission capabilities.It can better improve the current lack of thorough communications.To solve this problem,we use the spread spectrum method to communicate in this design,but general spread spectrum methods such as direct-sequence communications are inefficient.Therefore,it is proposed to use parallel combined spread spectrum communication to improve efficiency.The parallel combined spread spectrum communication not only has the anti-jamming capability and the good secretiveness of the traditional spread spectrum system,but also has a relatively high frequency band utilization and information transmission capability.The main contents of this paper include the following aspects:(1)This paper proposes a new PCSS communication model-multiple detection PCSS communication system.The candidate sequences are blocked and cyclically shifted at the transmitting end.When the receiving end despreads,the sequence number of the pseudo code is determined first,and then the symbol block in the selected sequence is determined,and then the phase in the selected symbol block is determined.Thus completing multiple tests.The multiple detection can reduce the system's bit error rate and improve system communication quality The party may also agree on a shift plan to increase the confidentiality of system communications..(2)This paper presents a new pseudo-code synchronization method-header detection pseudo-code synchronization.At the transmitter of the system,a pseudo-code sequence is selected to be the synchronization header sequence.When the receiving end carries out the pseudo-code synchronization,the local pseudo-code sequence is obtained by performing cyclic shift on the selected sequence of divided symbol blocks.Then capture tracking to achieve pseudo-code synchronization.This method reduces the number of shifts in the synchronization process,and the computational complexity is not high,which greatly improves the work efficiency of the entire system.(3)In this design,the entire system will be implementated by using hardware.It includes the analog part and the digital part.Analog part of the main analog signal processing.Transmitter for power amplification,impedance matching.The receiver completes the processing of the signal received from the antenna to meet the requirements for subsequent digital signal processing.The digital part mainly deals with the processing of digital signals,completing the serial port receiving and sending of signals,modulating and demodulating signals,coding and decoding of channels,and spreading and despreading signals.At this point to complete the design of the entire system.