SZ4IoT: an adaptive lightweight lossy compression algorithm for diverse IoT devices and data types: SZ4IoT: an adaptive lightweight lossy compression algorithm

The Internet of Things (IoT) is an essential platform for industrial applications since it enables massive systems connecting many IoT devices for analytical data collection. This attribute is responsible for the exponential development in the amount of data created by IoT devices. IoT devices can generate voluminous amounts of data, which may place extraordinary demands on their limited resources, data transfer bandwidths, and cloud storage. Using lightweight IoT data compression techniques is a practical way to deal with these problems. This paper presents adaptable lightweight SZ lossy compression algorithm for IoT devices (SZ4IoT), a lightweight and adjusted version of the SZ lossy compression method. The SZ4IoT is a local (non-distributed) and interpolation-based compressor that can accommodate any sensor data type and can be implemented on microcontrollers with low resources. It operates on univariate and multivariate time series. It was implemented and tested on various devices, including the ESP32, Teensy 4.0, and RP2040, and evaluated on multiple datasets. The experiments of this paper focus on the compression ratio, compression and decompression time, normalized root mean square error (NRMSE), and energy consumption and prove the effectiveness of the proposed approach. The compression ratio outperforms LTC, WQT RLE, and K RLE by two, three, and two times, respectively. The proposed SZ4IoT decreased the consumed energy for the data size 40 KB by 31.4, 29.4, and 27.3% compared with K RLE, LTC, and WQT RLE, respectively. In addition, this paper investigates the impact of stationary versus non-stationary time series datasets on the compression ratio.