Facing the obstructed path problem in indoor TOA-based ranging between IEEE 802.11 nodes

TOA-based technology represents an alternative to overcome the current limitations of the indoor positioning systems using IEEE 802.11 networks infrastructures. The authors propose a new TOA-based ranging technique, which is the essential step towards the pursued positioning system, but tests have confirmed that its accuracy drastically decreases when a severe material obstruction exists between the involved nodes. This contribution describes an approach to overcome this problem and proposes a ranging algorithm specifically designed for such situations. Tests performed with a developed ranging prototype demonstrate the validity of the proposed solution.