The world of technology has given mankind a powerful way for interaction using telecommunication. When invented by Alexander Graham Bell, it was a wired transmission of electrical signals representing information. Since then, telecommunication technology has achieved tremendous improvement from text, voice transmission to a modern age high speed real time multimedia content. The challenges for today's technology is to develop standards that can help operators to keep the cost per bit as low as possible and keep on reducing, maintain backward compatibility so as to gain maximum benefit from the investments. The newer modulation schemes and improved advanced antenna technologies are helping to achieve the newer heights of success. The technology so far has developed through 1st, 2nd and 3rd generation phases and currently 4G (4th Generation) is the best experience till date for users. In March 2008, the International Telecommunications Union-Radio communications sector (ITU-R) specified a set of requirements for 4G standards, named the IMT-Advanced (International Mobile Telecommunications Advanced) specification, setting peak speed requirements at 100 megabits per second (Mbit/s) for high mobility communication (such as from trains and cars) and 1 gigabit per second (Gbit/s) for low mobility communication. To meet IMT-Advanced requirements, IEEE 802.16m (Mobile WiMAX) an IEEE standard and Long Term Evolution (LTE) from 3GPP groups are considered and both satisfy the IMTAdvanced requirements. 4G goals are challenging compared to 3G standards. To achieve the 4G requirements, two standards were candidates. IEEE developed Mobile WiMAX, a successor of IEEE 802.16 (2009) standard for Local and metropolitan area networks. Mobile WiMAX supersedes the IMT-Advanced requirements using OFDMA modulation and advanced MIMO antenna technology. Long Term Evolution (LTE), a 3GPP technology developed to meet the IMT-Advanced requirements uses OFDMA modulation scheme for Downlink and SC-FDMA for Uplink to improve PAPR and save battery power on mobile user devices. LTE also uses advanced MIMO antenna technology to increase the data rates and supersedes the IMT-Advanced requirements. This thesis investigates physical layers of LTE and WiMAX designed for improved data rates, system capacity, and robustness. Both technologies use variable bandwidth and flexible adaptive modulation techniques with efficient physical resource allocation to utilize the available channel and achieve the best possible throughput. Best utilization of Time and frequency resources is the key for best performance results. Physical layer parameters for WiMAX and LTE use physical resources in different ways and achieve optimized performance under real time scenarios. Various aspects of physical layer results and parameters are analyzed for understanding the similarities and differences amongst the technologies.