A Survey on Scalable Wireless Indoor Localization: Techniques, Approaches and Directions

The demand for scalable indoor localization systems is increasing more than ever due to the emerging phenomena of the Internet of Things, industry 5.0, where humans and robots work together, and ubiquitous connectivity. As a result, various indoor localization systems based on wireless technologies have been proposed in the literature to provide accurate indoor localization services. While there have been advances in indoor localization systems using wireless technologies, there is still a need to address the demands for multiresolution and scalability capabilities. Thus, this paper provides an in-depth analysis of indoor localization techniques and approaches from a scalability perspective, critically analyzing their capabilities and limitations. Therefore, the main objective of this paper is to highlight the key research challenges of implementing multiresolution and scalable wireless indoor localization systems for large-scale environments with the prime concern of identifying key challenges and future research directions.