Research On Multi-carrier Message-driven Frequency Hopping

The joint operation of information is the essence of the modern war,which has higher requirements of the reliability and validity for the anti-jamming ability and data transmission rate,in military communication systems.To provide a strong guarantee for the safety and effectiveness of military communications,the research of the new frequency hopping(FH)technique is mainly focused on,which has strong anti-interference ability,high speed and high spectral efficiency.Message-driven frequency hopping(MDFH)technique is the hot researching field recently,where part of the transmitted source information is used to select the carrier frequency,instead of the function of the PN sequence,and the system spectrum efficiency and data transmission capabilities are improved without increasing the bandwidth and power consumption.Then,the single-carrier MDFH system is extended into the multi-carrier MDFH system in enhanced message-driven frequency hopping(E-MDFH)technique,where a plurality of frequency channels are occupied for each hop to transmit data,instead of only one frequency channel for each hop,in order to further improve the frequency utilization.Based on the multi-carrier message-driven frequency hopping communication mechanism,the main research contents are as follows:(1)The basic principles of traditional FH,MDFH and E-MDFH techniques are studied.The process of transmitting and receiving and the multi-user collision of the frequency hopping multiple access(FHMA)system,and the process of transmitting and receiving of MDFH and E-MDFH systems have been analyzed.Due to the existence of the difference between the carrier index in E-MDFH systems,it is found that the restoration error of the carrier bit and the adjacent ones can be caused when one carrier detection error occurs,which leads to the error of the whole carrier bit stream,and also the system will demodulate the signal which does not exist,resulting in more errors in the detection of conventional symbols.Besides,when the conventional symbol is modulated by high order,a bit stream error can also be coused.By analyzing the bit error rate(BER)and spectrum efficiency of E-MDFH systems,the simulation results show that the spectrum efficiency of the E-MDFH system is higher than that of the traditional FH system under the same channel environment and BER performance requirements.(2)Aiming at the problem of serial bit stream error in the E-MDFH system,the E-MDFH system is improved by adding an interleaving coding module,to solve the problem and reduce the error rate.The simulation results show that the use of interleaving coding can solve the problem well in the E-MDFH system and improve the system BER performance.(3)Based on orthogonal frequency division multiplexing(OFDM)and the E-MDFH system with interleaving coding module,a multi-carrier message-driven orthogonal frequency hopping(MC-MDOFH)system model is first proposed in order to applied to burst communication.Then,the signal spectrum,transmitter and receiver block diagram of the MC-MDOFH system are analyzed in detail,and the design of the signal frame format is also described,including the preamble sequence and the data symbol structure.Finally,the spectrum efficiency and BER performance of the system is simulated and analyzed,and the frequency offset correction of the system is carried out by using the preamble sequence,and also the BER performance of the burst MC-MDOFH system is simulated.The simulation results show that the spectrum efficiency of MC-MDOFH system is equal to that of the E-MDFH system,and the BER performance of MC-MDOFH system is better than that of the E-MDFH system,and the designed preamble sequence can effectively realize the synchronization of the system and improve the system performance.(4)The multi-carrier message-driven free carrier hopping(MC-MDIS)communication technique is further studied,and then the signal spectrum,transceiver model and working principle of MC-MDIS system are discussed in detail.Through the application example,the bit vector misalignment problem is analyzed in detail,and the bit vector reset(BVR)algorithm is studied to solve the problem.Through theoretical derivation and simulation,the BER performance and spectrum efficiency of the MC-MDIS system are analyzed and compared,and the optimal system parameters are obtained.The simulation results show that the BVR algorithm improves the performance of BER significantly,when the number of packets in the system is small or the SNR is low.When a small decimal semi-octets is adopted in modulation,the spectrum utilization ratio of the system has obvious advantages,compared with the OFDM system.