Classification of User Trajectories in LTE HetNets Using Unsupervised Shapelets and Multiresolution Wavelet Decomposition
Diego Castro-Hernandez, Raman B. Paranjape · IEEE Transactions on Vehicular Technology · 2017
The classification of user trajectories in Long-Term Evolution (LTE) heterogeneous networks (HetNets) is investigated in this paper. We propose a methodology to classify user trajectories based on the measurement reports submitted to the serving base station as part of the handover process; we propose to consider each measurement report as a time series. This methodology allows base stations to automatically and autonomously discover the radio-frequency (RF) conditions of their cell edge (e.g., signal strength degradation and interference levels). We propose the application of machine learning and data mining techniques to identify patterns in the reference signal received power measurement reports submitted by users as they approach the edge of the service area. Our time-series clustering algorithm based on unsupervised shapelets and multiresolution wavelet decomposition provided superior performance compared to a discrete Fourier transform (DFT)-based clustering algorithm. Our algorithm was able to provide clustering results with an average accuracy of 95%. Furthermore, the quality measure of the resulting clusters was up to 75% better, compared to the clustering results provided by the DFT-based algorithm. We also proposed a novel methodology to calculate a suitable number of clusters with no prior knowledge regarding the data; an average accuracy close to 90% was achieved.