MagneComm+: Near-Field Electromagnetic Induction Communication With Magnetometer

Guangtao Xue, Hao Pan, Yi-Chao Chen, Xiaoyu Ji, Jiadi Yu

Abstract: Near-field communication (NFC) technology emerges as a vital role with appealing benefits for users to improve mobile device’s functionality. Although today’s most smartphones and smartwatches come with NFC support, other mobile devices (e.g., PC and laptops) and IoT devices that don’t equip with dedicated radio modules cannot take advantage of wide-scale NFC capability. We design and develop <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MagneComm+</small> , an NFC-like implementation scheme without dedicated hardware and propose a novel near-field communication protocol that is applicable to almost all mobile devices and IoT devices. The key idea is to utilize the electromagnetic induction (EMI) signal emitted from the computing devices (e.g., CPUs) and captured by magnetometers on mobile devices for communication. We tackle challenges in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">data encoding/decoding</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">preamble detection</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">retransmission and error correction</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">multi-transmitter</i> , and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">full-duplex</i> schemes, to efficiently generate and reliably receive EMI signal with the hardware available on devices. We prototype <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MagneComm+</small> on both between laptops and smartphones, as well as between two laptops with an external magnetometer. Extensive evaluation results show that our <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MagneComm+</small> supports around <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><inline-formula><tex-math notation="LaTeX">$10~cm$</tex-math><alternatives><mml:math><mml:mrow><mml:mn>10</mml:mn><mml:mspace width="3.33333pt"/><mml:mi>c</mml:mi><mml:mi>m</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href="pan-ieq1-3133481.gif"/></alternatives></inline-formula></b> communication distance with average <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">110 bps</i> (bit per second) data rate on the normal-speed mode, and maximum <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17.28 kbps</i> on the full-speed mode.