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Moving towards 5G: Vision and Architecture Over the past few years, one of the key buzzwords in the mobile network industry has definitely been 5G. An increasing number of mobile network operators, equipment manufacturers, research organizations and governments are actively engaged in discussions on 5G and its key enabling technologies. In 2012, the International Telecommunication Union (ITU) coined the term “IMT- 2020” to tentatively describe 5G and announced its plan towards 5G. To be more specific, ITU plans to define 5G visions and requirements by 2015 and 2017, respectively. Then, suggestions on key enabling technologies and architecture which satisfy the defined IMT-2020 requirements will be gathered and evaluated by the second half of 2017. Based on the suggestions and evaluation results, the goal is to complete the 5G standardization by 2020. In accordance with this timeline, many countries and regions around the world have established organizations 1 tasked with better defining 5G services and infrastructure, while exchanging their intermediate views and technologies. lthough 5G requirements and technical specifications are still being discussed, there seems to be a common view on some of the 5G requirements: 5G should support 1,000 times higher overall capacity than the current LTE system and guarantee 1Gbps speed for every user. There are also diverse efforts being made by the global mobile network operators to define 5G and its requirements. For instance, the following is SK Telecom’s view on the 5G requirements. First, 5G should provide both 1,000 times faster speeds than LTE and ultra-low end-to-end latency of less than a few milliseconds. Second, 5G needs to accommodate 1,000 times more devices and things than LTE, and seamlessly connect them anywhere, anytime. Third, considering the massive amount of information to be collected from various devices and things, 5G is expected to offer personalized services based on dynamic and programmable network infrastructure and real-time data analytics. Fourth, 5G should be highly available, reliable and have zero-perceived service downtime. Lastly, 5G needs to be 100 times more energy-efficient compared to LTE, allowing massive deployment of infrastructure and devices in an efficient and scalable manner. Taking the full advantage of these rich 5G capabilities, our 5G vision is to promise differentiated values in areas of user experience, connectivity, intelligence, reliability and efficiency. The 5G requirements and visions should be carefully reflected when designing the 5G architecture. In our definition, the 5G architecture is mainly composed of three horizontal layers, namely “Innovative Service”, “Enabling Platform”, and “Hyper- Connected Infrastructure” to properly address the above-mentioned five requirements. A Innovative Service is the top layer that includes innovative 5G services. Built upon differentiated 5G infrastructure capabilities, 5G services will be able to offer a highly reliable and immersive user experience. In particular, ultra-high definition video streaming will eventually become services that provide virtual user experiences such as multi-view video streaming and even holograms. Furthermore, the sufficient bandwidth and high reliability offered by 5G will facilitate the emergence of remote robot controlling services and mission- critical IoT services. Enabling Platform is the middle layer that creates meaningful and service-centric values to support the upper “Innovative Service” layer by properly transforming the mechanical and disjointed underlying networks to a service-oriented infrastructure. It utilizes two key enablers to perform this task. The first key enabler is Network Functions Virtualization (NFV) and Software Defined Networking (SDN), which makes the network much more dynamic, agile, on- demand, and flexible. The second key enabler is a well-defined set of Application Programming Interfaces (APIs), which offer the ability to automate and orchestrate the network both internally for automated network operations and optimizations, and externally to the customers and third party applications along with telco assets including TPO (time, place, occasion). Hyper-Connected Infrastructure is the bottom layer that can deliver massive amounts of data to the “Enabling Platform” layer in a very efficient and seamless manner. Due to the massive amount of transmission data and stringent latency requirements, this layer will include not only the existing network technologies (both as-is and evolved form), but also novel network technologies. It is necessary to develop a range of MOBILE WORLD CONGRESS DAILY 2015 | Figure 1: Key Values for 5G Figure 2: SK Telecom's 5G Architecture technologies capable of enhancing cell splitting, spectral efficiency, channel frequency bandwidth and network operation efficiency. While both 3G and 4G radio access networks (RANs) were built as stand-alone network, 5G RAN will be deployed by integrating the existing LTE-Advanced (LTE- A), its evolution technologies, and new radio access technologies (RATs). Due to their heterogeneous nature, it is important to build an infrastructure where different radio access technologies are seamlessly integrated. 3GPP has been developing standards for LTE-A evolution in Release 13 and plans to start standardizing the new RAT in Release 14 from 2016. Therefore it is important to continuously develop both technologies to realize 5G RAN. One recent development has been the commercialization of one of the key LTE-A evolution technologies called tri-band carrier aggregation, and a PoC trial of 15GHz and 28GHz cm/mm-Wave communication systems providing peak data rates of 5Gbps in June 2014. A pre-5G trial service is planned for 2018. To achieve successful commercialization of 5G, it is necessary for governments, industry and academia to closely collaborate, while diligently playing their respective roles. Governments need to develop new regulations and measures to promote standardization on the competitive frequencies that can be used globally. The industry should make proactive efforts to verify key 5G enabling technologies and push for the technical standardization, while the academia is expected to conduct ambitious studies in diverse fields with an open perspective to discover yet more creative technologies for 5G and beyond. Furthermore, it is imperative for the global community to reach a consensus on the vision, requirements and timeline for the 5G system so as to set a uniform direction for 5G. 1 Europe: 5GPPP, China: IMT-2020 PG, Japan: 2020 and Beyond Adhoc, Korea: 5G Forum Monday 2nd March PAGE 9