Experimental Implementation of 2-Element Antenna Localization System for Small Cell Location Planning of Hetnets

In cellular heterogeneous networks, well-targeted small cells increase capacity, enhance coverage, offload traffic from the existing macro cell and ensure balanced load in the network. This paper experimentally demonstrates the use of a 2-element localization system for the purpose of small cell location planning. A centralized localization system that utilizes a differential 2-element antenna array to perform user localization and identify positions for small cell deployment is presented. The base station, which can also be the network gateway, is connected to two collinear antennas separated by λ/2. The relative phase of each antenna was varied using a phase shifter. The combined output of the two antennas was used to create sum and difference radiation patterns, and to steer the antenna radiation pattern to other angular positions. The system applies a simple RSSI based algorithm to calculate user AoA, range and user population per sector of the network to determine optimum positions for small cell deployment. Experiment with seventeen users in a LOS WiFi environment showed accurate angle of-arrival estimation and a range estimation with MAE of 2.19m relative to the BS. User clusters and positions for small cell deployment were correctly located.