Wi-Fi and LTE Coexistence in Unlicensed Spectrum

Abstract

Comprehensive growth of the internet and supporting technologies has increased the competition in the technological market to provide highly reliable services. With improved services with exceptional features in new applications, it's driving the need for high bandwidth in the licensed spectrum. But because of the increase in need, licensed spectrum has been exhausted by the usage and bandwidth for service is decreasing. To mitigate this problem and to upgrade the current cellular infrastructure to support high bandwidth needs and to serve reliable services, researchers are looking at usage of unlicensed spectrum. Utilization of unlicensed spectrum in the past has been very minimal compared to the total bandwidth available. Hence, using unlicensed spectrum will be a promising option to support ever increasing bandwidth needs. Deploying the data from licensed band into unlicensed band requires careful observation of unlicensed band to make sure it supports all of its native protocols such as Wi-Fi. LTE-U and LTE-LAA have emerged as the technology of choice to deal with the need. Both the technologies follow different approaches to serve the licensed spectrum data through the unlicensed spectrum without harming its normal functionality. The problem associated with coexistence of Wi-Fi with LTE, and their deployments in the 5 GHz band has been illustrated. The paper is concluded by depicting the flow of the LBT design structure depicting functionality in different layers to achieve coexistence of Wi-Fi and LTE in unlicensed band.