Inverse Control of Nonlinear Distortion in Adaptive System

Nonlinearity of digital receiver is actively utilized for security of communication. This paper develops an adaptive nonlinear transform algorithm for enhancing anti-attack ability of communication system. The nonlinear characteristic which is transparent to authorized consumer, is added to the linear modulated signal. The useful information is hidden in nonlinear distorted signal which seems to be meaningless. For non-cooperative receiver, the obstacle of nonlinearity is produced in receiving and judging process. On the other hand, cooperative receiver can successfully obtain the information by inverse nonlinear transform using private key. A blind identification of adaptive nonlinear control for inverse nonlinear transform is proposed. Experimental results on simulation show that with the proposed technique, the Spurs-Free-Dynamic-Range with 16QAM signal after nonlinear transform is 31dB worse than that of before nonlinear transform. The 16QAM signal can be recovered by inverse transform.