This article proposes a set of strategies to improve the performance stability and reliability of purely software ToA-based ranging with off-the-shelf WLAN equipment. Taking as starting point the core design lines proposed in (1), where timing measurements were taken at OS level using the CPU clock of the client device, we optimize the OS configuration and the capture of the time-stamps. Results obtained with a prototype demonstrate that the proposed enhancements improve the performance stability by a factor four. The interest in this kind of ranging methods is because they enable cost-effective and accurate positioning in GNSSless environments.Peer ReviewedPostprint (published version
The search for a unique and globally available location solution has attracted researchers for a long time. However, a solution for indoor scenarios, where high accuracy is needed, and Global Positioning System (GPS) is not available, has not been found yet. Despite the number of proposals in the literature, some require too long a calibration time for constructing the fingerprinting map, some rely on the periodic broadcast of positioning information that may downgrade the data communication channel, while others require specific hardware components that are not expected to be carried on commercial off-the-shelf (COTS) wireless devices. The scalability of the location solution is another key parameter for next-generation internet of things (IoT) and 5G scenarios. A passive solution for indoor positioning of WiFi devices is first introduced here, which merges a time-difference of arrival (TDOA) algorithm with the novel fine time measurements (FTM) introduced in IEEE 802.11mc. A proof of concept of the WiFi passive TDOA algorithm is detailed in this paper, together with a thorough discussion on the requirements of the proposed algorithm.
This paper presents an analysis of teletraffic variables in cellular networks. The variables studied are the time between two consecutive handoff arrivals and the handoff delay. These teletraEc variables are characterized by means of an advanced software simulator that models several scenarios assuming Fixed Channel Allocation. Information about the Quality of Service is also provided. A large set of scenarios has been simulated and the characterization results derived f?om its study have been presented and analyzed.
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