Eckford, Andrew W.2017-07-272017-07-272016-09-212017-07-27http://hdl.handle.net/10315/33430LTE in the unlicensed spectrum, is becoming a popular area of research. Since LTE-Unlicensed (LTE-U) provides subscribers with higher-quality mobile voice, and video experience in high-traffic or low-signal locations, a fair coexistence mechanism with other networks, like Wi-Fi is essential. In this thesis, we propose two coexistence mechanisms that could be employed to ensure a fair channel access. First, we consider coexistence mechanism fundamentals, and then downlink system performance of two coexistence mechanisms are analyzed for multi-operator LTE-Unlicensed (LTE-U) deployments with different simulation scenarios, using NS-3. First we introduce the most trustworthy coexistence mechanism, and then a high-performance coexistence scenario is provided. We conclude that Licensed Assisted Access (LAA) can coexist with Wi-Fi without impacting Wi-Fi more than an equivalent Wi-Fi network. In the second part, uplink performance evaluation of LTE in licensed spectrum is also demonstrated.enAuthor owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Electrical engineeringElectronic Thesis or Dissertation2017-07-27LTE cellular systemUnlicensed spectrumCoexistence schemePerformance analysisLTE-ALTE-ULAALWACSATDuty cycleLBTListen-Before-TalkSDL