MISO Magnetic Induction Communication Transmission Method Based on Pre-coding Within Transmitting Coil Array

The mutual inductance impedance within the multiple-input single-output (MISO) magnetic induction coil array is the main factor limiting the transmission rate. In this regard, this paper proposes a MISO magnetic communication transmission method based on precoding in the transmitting coil array. Firstly, the source of interference in the coil array of the MISO magnetic induction communication transmitter is analyzed. The impedance matrix of the transmitting coil is estimated according to the frequency of the modulation signal and the physical relationship of the coil. The zero-forcing precoding matrix operation method is used to zero the mutual inductance impedance between different transmitting coils in the impedance matrix, in order to eliminate interference in the transmitting coil array. Secondly, the modulation signal is loaded into each transmitting coil of MISO magnetic induction communication, and the induced electromotive force is generated in the receiving coil through the magnetic induction medium to complete the signal transmission. This method can eliminate the mutual inductance impedance in the transmitting coil array and suppress the interference between coils. In this paper, we design relevant simulation experiments to verify the effect of the proposed method on the information transmission rate of a magnetic communication system. The experimental results show that when the transmission power is greater than 2.5 mW, the data transmission rate is greatly improved compared with the method without zero forcing precoding. When the transmission power reaches 5 mW, the data transmission rate can be increased by about 11%.