The world of technology is always been completive and dynamic. Innovation however is not simply a matter of introducing new technology or adding new services. Operators need to continue to reduce the production cost of traffic and get more capacity from existing investments for longest period of time. The 3rd Generation Partnership Project (3GPP) family of standards- GSM, EDGE, WCDMA, HSPA and LTE is a proof that standardized, evolutionary solutions can meet this challenge over several decades. The 3GPP family, moves from basic voice and text messages to advance multimedia services over mobile broadband based on globe standards and ensures interoperability, roaming and backward compatibility. The 3GPP and 3GPP2 aligned together choose LTE as their next generation mobile broadband technology. The 3G goals are wide and compatibility requirements are key focus. In 1998, wideband CDMA got strong support to recognize as UMTS terrestrial air interface for FDD frequency band. Wideband CDMA bandwidth of 5MHz. Fast data rate of 144 and 384 kb/s uplink and downlink respectively, lack of spectrum issue and offer more multipath than narrow bandwidth, increasing diversity and resulting in improve performance. Some of the WCDMA promises include multirate services, large user capacity, and interference reduction and fast power control. The 4G LTE is an excellent complement to WCDMA network. LTE technology can be used to enhance data performance with wide-area WCDMA coverage. The first release ensures the data rate of 100Mb/s (DL) and 50Mb/s (UL), also simplified radio-network architecture design which reduces cost. LTE supports both duplexing (FDD/TDD), as well as the ability to allocate large number of different spectrum. LTE aims for 3GPP (WCDMA) and as well as 3GPP2 (CDMA2000).Various aspect of LTE encompass spectrum flexibility, multiple-antenna transmission and inter-cell interference coordination. LTE introduce the concept of physical resource block (PRB) which makes it effective in both frequency and time. This thesis investigates the physical layer techniques used to increase data rate, user capacity and reliability in WCDMA and LTE. Wide spectrum used in WCDMA and LTE is using variable bandwidth. UL and DL data modulation schemes and accessing techniques are well utilized for high data rate. Analyzing OFDMA and SC-FDMA used for reducing interference between carriers and to keep peak-to-average ratio low as to safe battery life in UL.