This document is a seminar report submitted by Ganesh Hegde on the topic of wireless systems and challenges in 5G. It provides an overview of the evolution of wireless technologies from 1G to 5G networks. 1G networks used analog signals and allowed only voice calls. 2G introduced digital networks and SMS. 3G enabled broadband internet access on phones. 4G provided faster speeds but 5G is expected to offer ultra-fast speeds over 100Mbps, low latency, better reliability and ability to connect many devices simultaneously. However, 5G networks will pose complex challenges in network densification, management of heterogeneous networks and meeting stringent quality of experience requirements.