A Software-Defined Radio Receiver for Wireless Recording From Freely Behaving Animals

• Published in: IEEE transactions on biomedical circuits and systems Vol. 13; no. 6; pp. 1645 - 1654
• Main Authors: Jia, Yaoyao, Lee, Byunghun, Kong, Fanpeng, Zeng, Zhaoping, Connolly, Mark, Mahmoudi, Babak, Ghovanloo, Maysam
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.12.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Action Potentials; Animal behavior; Animals; Behavior, Animal - physiology; Broadband; Computer programs; Data acquisition; Data loss; Electrodes, Implanted; Electrophysiology; Embedded systems; Equipment Design - methods; Graphical user interfaces; implantable medical devices; neural interfacing; On-Off Keying; Radio frequency; Radio receivers; Rats; Receivers & amplifiers; Recording; RF signals; Signal Processing, Computer-Assisted; Software; Software radio; software-defined radio; Surgical implants; System on chip; Tethering; Wearable Electronic Devices; wireless; Wireless communication; Wireless communications; Wireless sensor networks; Wireless Technology - instrumentation
• ISSN: 1932-4545; 1940-9990
• DOI: 10.1109/TBCAS.2019.2949233

To eliminate tethering effects on the small animals' behavior during electrophysiology experiments, such as neural interfacing, a robust and wideband wireless data link is needed for communicating with the implanted sensing elements without blind spots. We present a software-defined radio (SDR) based scalable data acquisition system, which can be programmed to provide coverage over standard-sized or customized experimental arenas. The incoming RF signal with the highest power among SDRs is selected in real-time to prevent data loss in the presence of spatial and angular misalignments between the transmitter (Tx) and receiver (Rx) antennas. A 32-channel wireless neural recording system-on-a-chip (SoC), known as WINeRS-8, is embedded in a headstage and transmits digitalized raw neural signals, which are sampled at 25 kHz/ch, at 9 Mbps via on-off keying (OOK) of a 434 MHz RF carrier. Measurement results show that the dual-SDR Rx system reduces the packet loss down to 0.12%, on average, by eliminating the blind spots caused by the moving Tx directionality. The system operation is verified in vivo on a freely behaving rat and compared with a commercial hardwired system.