5G Technology stands for the 5th Generation Mobile technology. 5G is a next major phase of mobile telecommunications standards beyond the 4G standards.5G is expected to provide speed upto 10Gbit/s, wider frequency band, high increased peak bit rate, high system spectral efficiency, ubiquitous connectivity and a significant increase in  QoS as compared to current 4G technology. Evolution of mobile communication technology to 5G is discussed in this review, followed by protocol stack and 5G architecture. A wide comparison is given between the various generations so as to compare why 5G technology is better and needed.