Adaptive Parallel DCSK with Code Index Modulation for Implantable Sensor Networks

Intra-body communication is limited by the complex biological organization of the human body, and the signal is subject to severe attenuation and multipath interference during propagation. In this paper, an adaptive parallel transmission with code-indexed modulation and differential chaotic shift keying (A-PT-CIM-DCSK) technique is proposed for implantable sensor networks. The number of parallel transmission channels is adaptively adjusted through least squares for channel estimation to achieve optimal transmission, enhancing the robustness of the system while maintaining a high data rate. The computational complexity is reduced by the cyclic shift of chaotic sequences. The theoretical bit error rate (BER) formula of A-PT-CIM-DCSK over the generalized Nakagami channel is derived, and its performance is verified by Monte Carlo simulations. The simulation results show that compared with the conventional CIM-DCSK system, the proposed scheme can achieve higher data rates while maintaining a lower BER over intra-body fading channels.