UWB-TWR performance comparison in a hybrid node network

Sammanfattning: This thesis investigated the performance of a positioning system that utilised UWB technology where devices regularly shifts between acting as an initiator and as a responder for distance measurements between each other. The goal was to investigate existing positional techniques and to implement a novel network where devices initiates and responds to distance measurement exchanges. Additionally, the intention of this positioning system is to prevent severe work accidents and reduce vehicle congestion costing lives, money and time in industrial workplace environments. In the thesis, two ranging techniques, skew-aware single-sided two-way ranging (SASS-TWR) and asymmetric double-sided two-way ranging (ADS-TWR) were compared to each other as well as two MAC protocols, CSMA/CA and the token ring protocol. Results showed that SASS-TWR and ADS-TWR had similar precision, but SASS-TWR was faster, making it the preferred option in a positioning system. For the MAC protocols, simulations showed that the token ring protocol outperformed CSMA/CA but had a major flaw in its current implementation with the lack of recoverability in cases where devices in the network stops functioning or leaves. The conclusion is that both ranging techniques are viable options, and for the MAC protocols, CSMA/CA could be used but lacks scalability. The token ring protocol outperformed CSMA/CA in speed and scalability but requires improvements in recoverability before it could be used in a positional system intended for the industrial workplace.