 In order to best appreciate how the standardization took place and what interesting lessons we can draw from there, we need to look at the overall evolution process that took place in 4G standardization. The long-term evolution and LTE advanced actually took a number of steps over years that resulted into the technology we see today. In this module we will see what is the concept of releases and how the overall evolution took place. The 3GPP Alliance started releasing documents that built upon the existing technology and recommended certain technological advancements and services. In 2000, the first 3G standard was released. It was based on the famous GSM 2G architecture and the 2.5G standard. 2.5G actually was a step towards providing data services to the GSM users. So the first release came in around 2000, specifically in 1999. It's known as Release 99, followed by 4th and 5th releases. And the process continued till we see the LTE and LTEA today. Let us look at the timeline. Here we see the universal mobile telecommunication system UMTS introduced the Release 99 recommendations that included the incorporation of data services on circuit switched voice networks. In release 4 and 5, certain recommendations were made to improve the data rate. The HSTPA and HSUPA were all related to the high speed packet access, speed being in the order of few kilobits per second, improving to megabits per second in the upload, download and overall call the high speed packet access architecture. The HSTPA plus was an improvement to the HSTPA by improving certain technologies at the physical layer. Then we started seeing LTE and LTEA around 2010. Now if you observe the three strata or the three layers, we see that the overall LTE architecture is based around three key principles, that is improving the technology as a radio access network technology. To have a better core that incorporates better interconnection between the radio side and the backend services. In 3GPP architecture around release 8, in LTE evolved packet core was introduced which obviated certain over budgeted and surplus technological elements in the network core. And then on the services side, the last layer here, we see that before the advent of voice telephony on IP networks, the circuit switched voice was the only offing along with the short message service. Then the IP multimedia system came in that included the introduction of certain voice services and features. With an improvement of technology, high data rates, multimedia telephony was introduced that adds higher layers of data rate to have better user experience. And then around the same time as in LTE and the evolved packet core at the radio side as well as the core side. The common IP multimedia subsystem recommendations were also introduced to have better interoperability with other standards and technologies to have better and user friendly services. Now, if we look at the overall scheme of things, we realize that 3GPP is not specifically focused either to the core side or to the access side or to the services side. But it involved recommendations across different times in multiple areas.