Commodity-level BLE backscatter

Abstract

The communication reliability of state-of-the-art Bluetooth Low Energy (BLE) backscatter systems is fundamentally limited by their modulation schemes because the Binary Frequency Shift Keying (BFSK) modulation of the tag does not exactly match commodity BLE receivers designed for Gauss Frequency Shift Keying (GFSK) modulated signals with high bandwidth efficiency. Gaussian pulse shaping is a missing piece in state-of-the-art BLE backscatter systems. Inspired by active BLE and applying calculus, we present IBLE, a BLE backscatter communication system that achieves full compatibility with commodity BLE devices. IBLE leverages the fact that phase shift is the integral of frequency over time to build a reliable physical layer for BLE backscatter. IBLE uses instantaneous phase shift (IPS) modulation, GFSK modulation, and optional FEC coding to improve the reliability of BLE backscatter communication to the commodity level. We prototype IBLE using various commodity BLE devices and a customized tag with FPGA. Empirical results demonstrate that IBLE achieves PERs of 0.04% and 0.68% when the uplink distances are 2 m and 14 m respectively, which are 280x and 70x lower than the PERs of the state-of-the-art system RBLE. On the premise of meeting the BER requirements of the BLE specification, the uplink range of IBLE is 20 m. Since BLE devices are everywhere, IBLE is readily deployable in our everyday IoT applications. CCS CONCEPTS• Networks → Network design principles; Sensor networks.

A Signal-to-Data Translation Model for Robust Backscatter Communications

“…• New Backscatter Paradigms: Recently, novel backscatter communication systems have been proposed that operate with different wireless systems, such as WiFibackscatter [17], [18], [19], [20]; Bluetooth backscatter [21], [22]; FM radio-backscatter [23]; and LoRa backscatter [24], [25]. These systems can extend the communication coverage and improve throughput, but require tag modification and increase tag cost.…”

Enabling software-defined PHY for backscatter networks

“…It differs from the classic FSK modulation in that the phase is continuous and the frequency transitions are Gaussian filtered. This problem is also introduced in [10]. Exactly realizing GFSK is impractical due to the Gaussian filtering is outside the scope of our baseband framework.…”

“…The past decade has seen numerous backscatter networking techniques proposed, which provide 𝜇𝑊 -level IoT connectivity while complying with a variety of wireless protocols [1][2][3][4][5][6][7][8]. However, obstacles still remain in the path of existing backscatter systems toward practical usage, issues include but are not limited to the inability to work with COTS receivers, support longer communication range, higher data rate, and concurrency [9][10][11][12][13][14]. Looking back into those existing work is necessary for this research area to move forward, where the inevitable process is to reproduce both hardware and software of previously proposed backscatter systems for comparison.…”

Intermittently-powered bluetooth that works

“…To address requirements ➊ and ➋ plenty of research has been dedicated to enabling ultra-low-power communication for popular wireless communication standards-leading to battery-free operation-through the backscatter principle. Recent examples of such wireless standard-compliant backscatter-based transmitters include LoRa [57], BLE [112] and Long Term Evolution (LTE) [22]. These wireless systems however do not address requirement ➌.…”