Secure transmission technology based on direct modulation with random channel characteristics

Aiming at the problem of insufficient security in the existing wireless data transmission, a security transmission technology based on direct modulation with random channel characteristics is proposed. The method first estimates channel characteristics using the preamble in the communication frame, and then embeds channel characteristics into the I/Q modulator. After that, the modulated constellation diagram undergoes random hopping of the constellation position compared with the original constellation diagram, thus achieving the effect of secure transmission. Due to the reciprocity of the uplink and downlink channels, channel characteristics estimated by the downlink receiver are almost the same as those estimated by the uplink receiver, and the correct plaintext data can be recovered by performing corresponding demodulation with them. Compared with the existing scheme of quantizing channel characteristics and then encrypting data, the method reduces the performance loss caused by quantization. In addition, its bit error rate is lower than that of the quantization method. In general, it has higher security and convenience.