Overview

The dataset includes distance and angle measurements obtained from a hybrid localization system integrated with the IEEE 802.15.4 Time Slotted Channel Hopping (TSCH) protocol [1]. The system combines multi-carrier phase difference (MCPD) or phase-based ranging (PBR) for distance estimation [2] with phase-based direction finding technique for angle-of-arrival (AoA) estimation [3], enabling hybrid localization using a single anchor node in an IoT network.

Setup

The measurements were collected in an office environment with a IEEE 802.15.4 TSCH network formed by six low-cost devices. One node, positioned in the center of a 5.1 m by 6.5 m room, acted as the root and performed localization of five surrounding nodes. Each device was built upon the AT86RF215 transceiver, which provides access to the phase of the received signal. To enable angle estimation, the root node was equipped with an RF switch and a uniform circular antenna (UCA) array composed of eight dipole elements spaced equally across 360 degrees. The pictures of the setup, used equipment and configuration are attached in the dataset files along with detailed description.

Measurement Procedure

The root of the node first formed a TSCH network. When all devices joined the network, the root started acting as an initiator, pinging its child devices. Each packet transmission initiated a Phase Measurement Process (PMP) that acquired phase measurements for angle and distance estimation [1]. During each PMP, the initiator captured eight reference phase samples from the first antenna to estimate and correct the carrier frequency offset (CFO), followed by ninety phase samples across the antenna array for AoA estimation. The switching between antenna elements was performed in a Round Robin (RR) pattern. The sampling rate of the system was 8 us per phase sample [3]. For distance estimation, fifteen frequency samples were measured sequentially using the Golomb frequency set to minimize measurement time and spectral overlap [2].

Software Implementation

The software implementation of the modified Contiki-NG stack that supports hybrid localization alongside TSCH communication is available at: https://github.com/9morano/contiki-ng/tree/vesna-atasw

Dataset Structure

The dataset is stored in a single JSON file named `data.json`. It is organized by device, where each entry includes the device address and an array of records. Each record contains the absolute slot number (ASN) corresponding to the TSCH schedule, two arrays of phase samples representing measurements from the initiator and the reflector, an array of eight reference phase values used for frequency offset calibration, and a second array of ninety phase values used for angle estimation. The JSON file can be parsed using Python built-in json module.