Mutual Lsp Platform-based Quasi-blind Design And Implementation Of Wireless Communication Systems

Communication countermeasures have become an important component of modern warfare with the development of electronic technology. Communication jamming technology and anti-jamming communication technology are two aspects of communication countermeasures. Jamming and anti-jamming constitute a contradiction. Quasi-blind wireless communication system will be a combination of these two aspects together to achieve comprehensive jamming and anti-jamming functions. Such thinking reflects a development trend of the future communications battle.The quasi-blind wireless communication's basic idea is: in a battlefield environment, the release of our high-power jamming signal suppressing the wireless communications of both sides. This is called"mutual blindness". But with the knowledge of the jamming signal characteristics, our receivers can rebuild the jamming signal and cancel it, to maintain communications. We have not really been suppressed, so called"quasi blindness".This system is designed to work in a strong interference and changing environment in the battlefield communications. When the receiver is used in the state of high speed movement, such as aircraft communications, the large Doppler frequency shift will bring difficulties to the synchronization of signal receiving. In the receiver designing, inhibiting the jamming signal and recovering the useful signal is the prerequisite for the working of the system. Therefore, specified signal processing algorithm need to be designed and tested through the hardware implementation.Quasi-blind wireless communication system has been studied based on the needs of military applications and technical characteristics of this system. We have investigated the signal processing algorithms, designed system parameters and structure of the transmitter, receiver and Jammer. Designing is based on meeting the performance requirements and complexity of achieving implementation. The most important algorithms include jamming cancelling, time synchronization of spreading codes, carrier frequency synchronization, frame synchronization, channel estimation and low bit-rate speech coding.In order to verify the feasibility of the quasi-blind wireless communication system, we have successfully built a demonstration system with Lyrtech? signal processing platform. The hardware implementation is based on model-based developing methods provided in the LSP solution. We can design the communication system in Simulink?, and carry out the fixed-point simulation, after that, the model can be transformed to VHDL codes and DSP C codes with the help of supporting software. After the model-based implementation, the system can run on the hardware platform.We carried out the communication experiments with the quasi-blind wireless communication system designed by LSP platform. Using the signal transmitter and receiver, we can achieve the real-time voice communication in the presence of a high-power jamming signal (the jamming to useful signal power ratio is 50dB), meeting the needs of the system design. Meanwhile, using RF equipment, the transmitter and receiver can establish a wireless RF transmission of voice signal.The novel quasi-blind wireless communication technology studied in this thesis has some prospective future military applications, such as effective jamming and communication in a battlefield environment, achieving wireless communications under cover.Meanwhile, the development method and procedure can be used as a reference for the future development of other systems on this LSP platform.