Abstract:

Long Term Evolution (LTE) and Long Term Evolution-Advanced (LTE-A) are the current leading data transfer technologies in the cellular industry and are used every day by people nationwide on multiple carriers. However, the quality of access to this technology varies among cellular network providers as well as the distance of a mobile user from a cellular tower and the number of mobile users on the network.  Cellular service providers frequently conduct drive tests to evaluate and determine their network coverage.  There are also a few third-party companies specializing in mapping the signal strength of an LTE channel for all of the major carriers.  In an educational setting, educators and students do not have access to the sophisticated and very expensive equipment and resources that these companies have access to and therefore undergraduate students do not get the opportunity to learn first hand how LTE drive tests are performed and how the data are collected and analyzed.

To provide undergraduate faculty and students with the means to teach and learn how to perform accurate LTE signal strength and coverage tests of different LTE frequencies in a specific geographical area, a senior undergraduate student and his advisor set out on an ambitious quest. That is, to develop an inexpensive but highly accurate LTE drive test tool for LTE educational purposes.  The main objective of this inexpensive tool is to enable the users (students and faculty) to accurately determine the LTE signal strength at a given location along with the geographical coordinates of that location. Through the use of this tool, the students and faculty should be able to produce a user-friendly and configurable heat maps from the data collected through the LTE drive tests.  

In this paper, we describe the successful development and packaging of a new educational tool, known as SoftDRiFT Kit as part of the senior student Capstone Project. SoftDriFT includes a Linux Ubuntu virtual machine that is configured to interface with an inexpensive Software Defined Radio (SDR) dongle (RTL-2832U NooElec NESDR Nano) and a GPS unit.  The tool is designed to collect and process LTE/RF Signal strength data and GPS coordinates data and to depict the results in a web-based heat-map.   We have extensively tested the tool and calibrated it against an industry-standard LTE coverage survey instrument for a number of LTE frequency bands.  We will present in this paper a number of hands-on exercises focusing on determining cellular service providers' LTE frequency channels, collecting data through test drives, analyzing the LTE heat-maps using Google Maps' API (Application Programming Interface),  determining cellular tower locations and comparing LTE signal strength between different cellular providers in different locations in a given geographical area.

Keywords:

undergraduate, LTE, SDR, Cellular, RF,