Nonlinear cancellation algorithm for cooperative jamming against frequency offset

To solve the problem of deteriorating nonlinear cancellation performance for cooperative jamming (CJ) caused by the frequency offset between the cooperative jammer and the authorized receiver, a nonlinear cancellation algorithm for CJ against frequency offset based on joint coefficient estimation of multiple adaptive filters was proposed. Considering the frequency offset introduced by the independent crystal oscillator and relative movement between the cooperative jammer and the authorized receiver, combined with the problem of nonlinear distortion in power amplifiers, a mathematical model for the CJ nonlinear reception signals was formulated. By decomposing the CJ joint channel into dynamic and static parts, the original system model was transformed into a recursive model. Based on the existence interval of the real frequency offset, by assuming the frequency offset value, multiple adaptive filters were used to jointly estimate the CJ nonlinear reconstruction coefficient, thereby achieving CJ cancellation. Simulation results demonstrate that the proposed algorithm outperforms existing nonlinear CJ cancellation algorithms in terms of anti frequency offset performance under the same complexity level.