Bi-directional channel modeling for implantable UHF–RFID transceivers in brain–computer interface applications

Bi-directional Brain–Computer Interfacing (BBCI) faces major challenges due to, in part, the difficulty of transmission of Electro-corticographical (ECoG) signals from the brain to external devices. For human subjects, safety and convenience would be greatly increased if we could replace the wired interface between the electrodes and the extra-cutaneous receiver with a wireless interface. All the technology that we have today using wires to connect the transmitter which setting on top of the electrodes with a reader located on the scalp which can create brain infection due to scar tissue and that might lead to serious brain injury. We have eliminated this risk by using passive transmitter setting on the electrode and transmit wirelessly to a reader sitting on the scalp using a back-scatter technique which shows a great potential in BCI Applications. This paper investigates the feasibility of passive Ultra High Frequency Radio Frequency Identification (UHF–RFID) for wireless communication between multiple transmitters inside the brain that collect vital data continuously and transmit them to an external controller located on the scalp outside the brain in order to design wireless communication channel inside the human brain considering network lifetime and minimize power consumption. Also, we emphasize the effect of increasing number of transmitters to maximize the throughput. Extensive literature survey shows that there is exists no model has been made for invasive BBCI applications based on UHF passive RFID. Results are presented with calculated Received Signal Strength (RSSI), Signal to Noise Ratio (SNR), Channel Capacity, Maximum number of the electrode, and Path Loss. These analyses are essential for building a brain–computer interface application. We showcase theoretical and experimental results based on a phantom model of the human brain using passive RFID as the implantable transmitter operating in UHF range. Based on these values we have concluded that UHF–RFID is a viable technology with multiple transmitters to a depth of 4 cm.