Path loss models with distance‐dependent weighted fitting and estimation of censored path loss data. Issue 14 (1st November 2016)

• Record Type: Journal Article
• Authors: Karttunen, Aki; Gustafson, Carl; Molisch, Andreas F.; Wang, Rui; Hur, Sooyoung; Zhang, Jianzhong; Park, Jeongho
• Is Part Of: IET microwaves, antennas & propagation. Volume 10:Issue 14(2016)
• Page Start: 1467
• Page End: 1474
• Publication Date: 2016-11-01
• Subjects: radiowave propagation -- cellular radio -- log normal distribution -- least squares approximations; path loss model -- distance‐dependent weighted fitting method -- censored path loss data estimation -- wireless propagation channel model -- single‐slope power‐law dependency -- multislope power‐law dependency -- log‐normally‐distributed shadowing attenuation -- ray tracing -- least‐square fitting -- path loss parameter extraction -- path loss value -- urban macrocells; Microwaves -- Periodicals; Microwave antennas -- Periodicals; Antennas (Electronics) -- Periodicals; Radio wave propagation -- Periodicals; Microwave communication systems -- Periodicals; 621.381305
• DOI: 10.1049/iet-map.2016.0042
• Languages: English
• ISSNs: 1751-8725

Abstract

Abstract : Path loss models are the most fundamental part of wireless propagation channel models. Path loss is typically modelled as a (single‐slope or multi‐slope) power‐law dependency on distance plus a log‐normally distributed shadowing attenuation. Determination of the parameters of this model is usually done by fitting the model to results from measurements or ray tracing. The authors show that the typical least‐square fitting to those data points is inherently biased to give the best fitting to the link distances that happen to have more evaluation points. A weighted fitting method is developed that emphasises the accuracy at the distance range that is consciously chosen by the user as most important for a system simulation. As a further important point that is typically not taken into account for path loss parameter extraction, the authors show that typically measurement data (but also ray tracing) is censored, i.e. path loss values above a certain threshold cannot be measured. The authors present examples of weighted fitting models, and models with and without the censored data, for 28 GHz channels in urban macrocells, and show that these effects have a significant impact on the extracted parameters and that the fitting accuracy can be improved with the presented methods.