M 2 I Underground Wireless Sensor Networks: Physical Layer Implementation Dr. Zhi Sun Hongzhi Guo (PhD) Darshit Makwana (MS) Lynn Sementilli Jiaqi Xie Introduction Objective: ● To design and develop a physical layer test setup for the metamaterial-enhanced magnetic induction (M2I) underground wireless sensor network (UWSN) communication system ● Verify accurate evaluation of the resulting bit error rates (BER) of various modulation types Data Analysis • Model ideal BER for various input signal-to-noise ratios using MATLAB • Determine the expected BER trend for the modulation types • Use ideal BER calculation to verify that experimental results will properly implement modulation types and BER calculations Methods and Equipment Hardware • Ettus USRP N210 software defined radio • UBX-40 Daughterboard • PCB-designed MI loop antennas • PC with Ubuntu GNU Radio Companion installed Analysis Methods • GNU Radio built-in modulation blocks in flowchart • Display BER and Tx/Rx signals in real-time GUI • Analyze saved binary files in Python and/or MATLAB Results • GNU Radio Flow-chart produces the theoretical BER trend for all types of tested modulation, thus verifying that the test setup should produce accurate measurements for modulations when using antennas in the underground environment • Bare MI loop antennas achieve signal transmission but with limited range and accuracy, as expected Conclusions • The developed GNU Radio test setup can be used for conducting experiments in the underground environment with the M2I enclosed antennas • Accurate readings of modulation BER can be read in real-time using the QT Time Sink as well as using the Python and/or MATLAB code to analyze saved binary files References [1] Z. Sun; I. F. Akyildiz (2010, July). Magnetic Induction Communications for Wireless Underground Sensor Networks. IEEE Transactions on Antennas and Propagation. vol. 58, no. 7. [2] H. Guo; Z. Sun; J. Sun; N. M. Litchinitser (2015, Nov.) M2I: Channel Modeling for Metamaterial-Enhanced Magnetic Induction Communications. IEEE Transactions on Antennas and Propagation. vol. 63, no. 11 [4] S. Haykin; M Moher, “Probability of Error Due to Noise,” in Communication Systems, 5 th ed. Hoboken, NJ: John Wiley & Sons, Inc, 2009, ch. 8, sec. 3, pp. 285-290 [5] S. Haykin; M Moher, “Digital Band-Pass Transmission Techniques,” in Communication Systems, 5 th ed. Hoboken, NJ: John Wiley & Sons, Inc, 2009, ch.9, sec. 1-7, pp. 313-338 [6] A. Goldsmith, “Performance of Digital Modulation over Wireless Channels,” in Wireless Communications, Stanford University, 2004, ch. 6, sec. 1, pp. 171-178 Future Research Perform underground environment experimentation at fixed distances Use the 3D-printed shell to enhance MI fields around currently tested coil antennas. Acknowledgements This work was supported by the US National Science Foundation (NSF) under Grant No. 1547908 Background Applications ● Earthquake prediction, oil reservoirs, nuclear plants, infrastructure monitoring, landscape management, homeland security, military uses Magnetic Induction (MI) Antennas ● Magnetic fields experience slight absorption and multipath fading Metamaterial-enhanced magnetic induction (M2I ) ● Used to enhance the magnetic field components and increase the penetration strength of the field Physical Layer in Electronics communications ● Method of transferring data using bytes Modulation ● Conversion of bits into a waveform: necessary to transmit the information over the channel medium Use tri-directional antenna for core of spherical device to produce omni-directional communication ● Develop Test Setup in GNU Radio Companion ● Conduct Ideal Modulation Simulations ● Perform initial Antenna and USRP tests using sinusoidal signal input BPSK - Binary Phase Shift Keying MSK - Minimum Shift Keying QPSK - Quadrature Phase Shift Keying BFSK - Binary Frequency Shift Keying DPSK - Differential Phase Shift Keying QAM - Quadrature Amplitude Modulation Main Physical Layer Modulation Types ● Top - Amplitude Shift Keying (ASK) ● Middle - Frequency Shift Keying (FSK) ● Bottom - Phase Shift Keying Figures 4&5: Transmitted and Received Relative Power from MI Loop Antenna Using Sinusoidal Signal Input Figure 2: Bit Stream of Transmitted (Green) and Received (Red) Bits from Simulation - MATLAB Analysis BPSK MATLAB Plot of Binary Data Figure 9: GNU Radio Simulation of BPSK Transmission with AWGN Figure 6: GNU Radio Test Setup for Modulation Simulation