This document summarizes positioning techniques for wireless sensor networks (WSNs) and Internet of Things (IoT) systems. It discusses both range-based and range-free localization methods. Range-based methods use distance or angle measurements between sensor nodes, including received signal strength indication (RSSI), time of arrival (TOA), time difference of arrival (TDOA), and angle of arrival (AOA). Range-free methods depend on node connectivity and do not require specialized hardware. The document reviews several algorithms and techniques for each category.