Baseband Design And System Implementation Of WBAN

With the trend of population aging and the increasing burden of medical resources,the wireless body area network(WBAN)for electronic medical monitoring,which is composed of several wearable or implantable devices and central nodes,has become one of the important application directions of the current medical Internet of Things.Based on the characteristics of long battery life and small size of body area network sensing nodes,the WBAN biomedical sensing technology suitable for wireless medical monitoring has received extensive attention from academia and industry in recent years.Designing digital circuits with low power consumption,small size,low delay,and high reliability transmission characteristics to meet the requirements ofWBAN protocol networking plays a key role in the development of modern body area network electronic medical monitoring.This paper has implemented the WBAN narrowband physical layer communication system based on the IEEE 802.15.6 protocol.The specific work is as follows:(1)SDR Based WBAN Wireless Communication System Verification PlatformBased on the software-defined radio(SDR)platform,namely GNU Radio and general software-defined radio peripherals,namely USRP N210,various data processing modules of WBAN are built,including packet framing,modulation and demodulation,and a series of verification modules to ensure reliable transmission.On this basis,a complete WBAN wireless communication system is modeled and its achievability is verified.By using the built-in modules of the GNU Radio platform,such as data stream format conversion,phaselocked loop and other baseband data processing circuits,as well as the general data processing capabilities of USRP N210,such as digital up-conversion and analog-side data processing capabilities,the WBAN wireless communication system establishment period is shortened.(2)Low Power Reconfigurable Digital Transceiver SystemOn the basis of software-defined radio platform verification,a low-power reconfigurable WBAN narrowband physical layer digital transceiver system based on IEEE 802.15.6 protocol is implemented through FPGA.The transceiver includes multiple circuit implementations such as spread spectrum,interleaving,scrambling,shaping filtering and modem.In order to ensure the reliability of data transmission,CRC and BCH codes are embedded,and a look-up table is used at the receiving end to realize the automatic error correction function of BCH errors of no more than two bits.The use of less resourceconsuming implementations in the shortened code insertion and removal algorithm can further reduce the power consumption of the digital transceiver.The system integrates GMSK and three offset DPSK modulation methods.The coherent demodulation and noncoherent demodulation schemes of GMSK modulation are simulated and tested,and the advantages of the two demodulation methods are analyzed through the comparison of resource consumption and demodulation performance.In order to improve the demodulation performance of the transceiver system,modules such as packet detection and timing synchronization are applied to the system receiver.(3)Tape-out and Testing of Launch Node ChipFinally,a complete WBAN sensor node transmitter chip including digital baseband and analog RF circuit is tested and verified here.The digital baseband part of the chip can support WBAN narrowband physical layer reconfigurable frame structure communication,and interact stably with the radio frequency circuit.The software-defined radio platform is used for node network reception,and it is actually measured that the receiving end normally receives the decoded data and meets the transmission distance requirement of the body area network.In short,based on the characteristics of small size,low power consumption,and strong reliability of WBAN network nodes,the prototype is first established and verified on the software-defined radio platform.Subsequently,the WBAN narrowband physical layer digital transceiver system is implemented in FPGA,and the common circuits of multiple modulation modes are multiplexed.It lays an extremely important foundation for the ASIC implementation of the WBAN sensor node with reconfigurable characteristics.Finally,the feasibility of the cross-platform wireless transmission system between the transmitter chip and the SDR receiver is verified here.