Research On Joint Transceiver Anti-jamming Based On The Difference Of Spatial Channel For Wireless Communication

The rapid development and broadcast properties of wireless communication caused increasingly complex electromagnetic environment. Especially in military communication, legitimate communicating parties often face a variety of unpredictable enemy interference, which caused a great threat to information Supremacy. The traditional anti-jamming technology in space-domain and mixed-domain is mostly based on the space angle difference, which could not accurately describe the difference of location. Accurately, due to the presence of reflection, diffraction and scattering in radio propagation environment, the fundamental difference between jammer and transmitter is the spatial channel difference caused by the difference of spatial location. In addition, only relying on the processing of receiver is not sufficient for mining the potential of anti-jamming in space-domain, and there are not so much of studies on joint transceiver anti-jamming in space-domain and mixed-domain. To solve these problems, we studied the joint transceiver anti-jamming technology based on the difference of spatial channel, which is supported by the National Natural Science Foundation of China.In this paper, the joint transceiver anti-jamming model based on the differences of spatial channels has been established, and then the principles of subspace projection, space-time and space-frequency hopping are analyzed. In the following, we proposed joint transceiver anti-jamming schemes based on subspace projection, space-time and space-frequency hopping. The main research contents are as follows:1. We established the joint transceiver anti-jamming model based on spatial channel difference. First of all, we verified the difference of spatial channel in different location through experiment which is the physical basis of anti-jamming. Then we established the joint transceiver anti-jamming model based on spatial channel difference, thus turning the anti-jamming problem into the optimization of transmitter’s pre-processing and receiver’s post-processing. Finally, we analyzed the principles of subspace projection, space-time and space-frequency hopping from the perspective of spatial channel difference, which provide theoretical foundation for the design of anti-jamming scheme.2. We proposed a joint transceiver anti-jamming scheme based on subspace projection. Through using interference subspace and legitimate channel matrix, the receiver can calculate the orthogonal and oblique projection operator to filtering interference. Then, the transceiver processing pair can be easily obtained on the basis of match transmission for equivalent MIMO channel. At last, we can get the final pair of pre-processing and post-processing by combining the transceiver processing pair with the projection operators. Simulation results show that the joint transceiver anti-jamming scheme based on subspace projection is much better than conventional spatial filtering, and has a performance appropriate to the theoretical SINR.3. We proposed joint transceiver anti-jamming schemes based on space-time and space-frequency hopping. Considering the communication scenario where the interference information is difficult to obtain, we lead time-domain or frequency-domain degree of freedom into space-domain so that transmitting signals experience the different equivalent channel at respective time or sub-carrier. Firstly, transmitter generates the pre-processing and send the signal out according to space-time pattern or space-frequency pattern; Then receiver computes the corresponding post-processing based on legitimate channel matrix and the shared pattern; Thus, receiver achieves the superposition of desired signal by matching transmission in time-domain or frequency-domain, and the reduction of interference because of the difference of spatial channel, then obtains the anti-jamming gain. Simulation results show that both space-time hopping and space-frequency hopping schemes have better anti-jamming performance than conventional transceiver matching and the anti-jamming gain should increase with hopping times in time-domain or frequency-domain.