The study explores Low Power Wide Area Networks (LPWAN) technologies designed for Internet of Things (IoT) applications in Smart Cities. LPWANs offer broad communication coverage over several kilometers, prioritizing low data rates for extended device autonomy, often up to a decade. This paper analyzes various LPWAN attributes, such as operational frequency bands, bandwidth capabilities, physical layer specifications, data transmission rates, and coverage areas. The research specifically investigates ecosystems and provides a detailed comparison of signal-to-interference-plus-noise ratio (SINR) and channel capacity among three key LPWAN technologies: LoRa, Sigfox, and LTE-M. The study compares SINR distribution functions for LoRa, Sigfox, and LTE-M End Devices (EDs) with varying quantities. The results show that LTE-M maintains a constant SINR due to its dedicated frequency band, avoiding interference. Sigfox outperforms LoRa, showing a gap increase from 22 to 40 dB with 1100 and 3000 devices. LTE-M outperforms LoRa and Sigfox in channel capacity, accommodating twelve users simultaneously. LoRa maintains a moderate capacity due to its wider band and orthogonal spreading factors. LTE-M’s efficiency comes at a higher transmission power cost, exceeding LoRa and Sigfox by 6 dB. Additionally, LTE-M operates in licensed bands, using a modulation scheme supporting more bits/symbols, potentially enhancing its performance. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.