A Low Complexity STPAP Algorithm based on Alternating Polarization Sensitive Array

Background: Space-time adaptive processing (STAP) has been widely used in the fields of communication, radar, and navigation anti-jamming. However, the traditional scalar array used by STAP has certain limitations，because it can only obtain spatial information. In order to further improve the performance of the space-time domain joint filtering technology, this paper replaces the traditional scalar array with an alternating polarization sensitive array (APSA). Compared with the dual polarization sensitive array (DPSA), it can not only obtain the polarization information of the signal, but also reduce the computational complexity of the algorithm. Methods: Using the polarization information of the signals, this paper realizes an alternate polarization sensitive array space-time-polarization adaptive processing algorithm (APSA-STPAP) based on the linear variance minimum criterion (LCMV). Different from the traditional LCMV criterion, this paper takes the space-time polarization joint steering vector of the desired signal and the interference signal as the constraint matrix, and uses the "1 condition" and "zero condition" as the constraint conditions to effectively suppress the interference signal and enhance the expectation signal. Results: The simulation results show that: (1) APSA-STPAP algorithm can achieve the same filtering effect as DPSA-STPAP algorithm. From the perspective of the spatial domain, time domain and polarization domain, it can form null in the direction of interference, effectively suppress the interference signal, and realize space-time-polarization adaptive processing. (2) Under the same conditions, APSA-STPAP algorithm can achieve the same filtering effect as DPSA-STPAP algorithm. there is a big difference between the two algorithms, APSA-STPAP algorithm can effectively reduce the amount of computation. Moreover, the dipole of alternating polarization sensitive array is halved, which reduces the coupling effect between electric dipoles, and is conducive to engineering implementation. (3) APSA-STPAP algorithm can maintain good anti-interference performance even when the electric dipole and anti-jamming degree of freedom are reduced by half, and its anti-jamming performance is similar to that of polarization sensitive array. The output SINR of DPSA-STPAP algorithm is about 3dB higher than that of APSA-STPAP algorithm. There is little difference between the anti- interference performance of APSA and DPSA.

Directional Modulation Technique Using a Polarization Sensitive Array for Physical Layer Security Enhancement

Directional modulation (DM), as an emerging promising physical layer security (PLS) technique at the transmitter side with the help of an antenna array, has developed rapidly over decades. In this study, a DM technique using a polarization sensitive array (PSA) to produce the modulation with different polarization states (PSs) at different directions is investigated. A PSA, as a vector sensor, can be employed for more effective DM for an additional degree of freedom (DOF) provided in the polarization domain. The polarization information can be exploited to transmit different data streams simultaneously at the same directions, same frequency, but with different PSs in the desired directions to increase the channel capacity, and with random PSs off the desired directions to enhance PLS. The proposed method has the capability of concurrently projecting independent signals into different specified spatial directions while simultaneously distorting signal constellation in all other directions. The symbol error rate (SER), secrecy rate, and the robustness of the proposed DM scheme are analyzed. Design examples for single- and multi-beam DM systems are also presented. Simulations corroborate that (1) the proposed method is more effective for PLS; (2) the proposed DM scheme is more power-efficient than the traditional artificial noise aided DM schemes; and (3) the channel capacity is significantly improved compared with conventional scalar antenna arrays.

Directional Modulation Technique Using a Polarization Sensitive Array for Physical Layer Security Enhancement

Directional modulation (DM), as an emerging promising physical layer security (PLS) technique at the transmitter side with the help of an antenna array, has developed rapidly over decades. In this study, a DM technique using a polarization sensitive array (PSA) to produce the modulation with different polarization states (PSs) at different directions is investigated. A PSA, as a vector sensor, can be employed for more effective DM for an additional degree of freedom (DOF) provided in the polarization domain. The polarization information can be exploited to transmit different data streams simultaneously at the same directions, same frequency, but with different PSs in the desired directions to increase the channel capacity, and with random PSs off the desired directions to enhance PLS. The proposed method has the capability of concurrently projecting independent signals into different specified spatial directions while simultaneously distorting signal constellation in all other directions. The symbol error rate (SER), secrecy rate, and the robustness of the proposed DM scheme are analyzed. Design examples for single- and multi-beam DM systems are also presented. Simulations corroborate that 1) the proposed method is more effective for PLS; 2) the proposed DM scheme is more power-efficient than the traditional artificial noise aided DM schemes; and 3) the channel capacity is significantly improved compared with conventional scalar antenna arrays.

Directional Modulation Technique Using a Polarization Sensitive Array for Physical Layer Security Enhancement

Directional modulation (DM), as an emerging promising physical layer security (PLS) technique at the transmitter side with the help of an antenna array, has developed rapidly over decades. In this study, a DM technique using a polarization sensitive array (PSA) to produce the modulation with different polarization states (PSs) at different directions is investigated. PSA can be employed for more effective DM for an additional degree of freedom provided in the polarization domain. The polarization information can be exploited to transmit different data streams simultaneously at the same directions, same frequency, but with fixed different PSs in the desired directions to increase the channel capacity, and with random PSs off the desired directions to enhance PLS. The proposed method has the capability of concurrently projecting independent signals into different specified spatial directions while simultaneously distorting signal constellation in all other directions. Mathematical analysis and design examples for single-beam and multi-beam DM systems are presented. Simulation results demonstrate that the proposed method is more effective for PLS and the channel capacity is significantly improved compared with conventional antenna arrays.