Operators have long been looking for ways to improve user experience and enhance utilization of expensive yet limited spectrum. More than ever before, 5G poses big challenges to operators in delivering quality network and optimal user experience as it is more complex than previous generation technologies with more spectrum bands to leverage and more services to support. As a key infrastructure of the digital society, 5G network not only serves individual users, but also supports digital transformation across industries. However, the evolution of radio resource management has been far behind that of radio access technologies due to much simpler service offering by previous technologies. Consequently, the increasingly diversified demands have further deepened the contradiction between "one-fits-all" network policy and differentiated user experience requirements. It is therefore of great importance for operators to deliver user-centric experiences for industry applications and consumers within limited network resources.

Introduction of Radio Composer
Understanding the need for operators to migrate from network-centered policy to user-centered policy to deliver the best experience in the most resource-efficient way, ZTE has innovatively proposed Radio Composer, the industry's first AI-driven context-aware, customized experience solution. Starting from the multi-layer of the whole network, Radio Composer enables multi-dimensional perception and machine learning of UE capability, service characteristic, network characteristic and inter-domain information, manages and optimizes radio resources to meet service requirements in a dynamic way by changing the traditional "best effort" mechanisms to "always optimal", and implements best mapping between service requirement and radio resources. It empowers user-centric policy to achieve a near real-time, customized user experience, and facilitates best user experience and highest network efficiency, so as to expand 5G users, unlock network potential, and promote the development of 5G industry and ecosystem.
Radio Composer takes the lead to use BBU native intelligence as the key driver of wireless network intelligence. With advanced radio resource allocation algorithm, it empowers consumers and industry applications with first-class performance without the necessity of extra hardware, and enables network policy shifting from "one-fits-all" to "context-aware". The AI training is implemented when CPU working at low load in order to minimize impact on legacy user experience, and computing capability coordination will be activated among neighbor cells with the growth of 5G users. The BBU native intelligence enables edge computing, which makes service applications as close to access as possible. This facilitates the implementation of low-latency services like gaming and AR/VR, which exploit more application scenarios and opportunities, accelerate the monetization of 5G networks, and increase the revenue of operators.
Radio Composer features flexible radio resource scheduling via network orchestration and user orchestration, in which user orchestration enables a digital-map-like experience navigation with smooth user experience, while network orchestration implements a lego-block-like resource adaption with higher network payload (Fig. 1). 

User Orchestration 
User orchestration targets at a smooth user experience through user steering and scheduling. Based on accurate predictions of network service capabilities and precise recognition of service requirements, together with terminal capabilities, it achieves flexible steering and scheduling among multiple frequencies in the network. In the field network, it improves the average throughput of cell-edge users by more than 300%, reduces handover delay by more than 48% and decreases low-speed NR user ratio by 51%.
For video streaming services, users can enjoy 1080p videos in areas with good coverage while degrading to 360p in areas with poor coverage. With Radio Composer, users will be steered to the cell with best experience when the experience is going to slide. Therefore, smooth user experience can be ensured through source cell experience evaluation and target cell experience prediction based on machine learning. The steering can also be implemented in the shortest latency without waiting for measurement feedback. In a summary, Radio Composer improves user experience and saves video buffer delay and first frame playback delay. 
In terms of slicing service, vertical applications in some scenarios, such as smart manufacturing, have stringent requirements on delay or reliability. Traditionally, more resources would be allocated in a fixed manner to guarantee the SLA requirement, resulting in a waste of resources. With Radio Composer, slicing resources can be managed dynamically through machine learning of traffic patterns on a daily or weekly basis. Therefore, Radio Composer allows two or more slices to be configured in the same network resources instead of one fixed slice, thus improving spectrum efficiency.
For terminals with different location characteristics for vertical applications such as drone inspection and differential protection services, the traditional policy is to use a unified priority to reside on the high-frequency network with 5G capability. With Radio Composer, the drone inspection service can be accurately guided to the low band for wide coverage while the experience is also on-demand; and the differential protection service with fixed-location terminals is preferentially directed to the high-frequency network to better meet the needs of users for differentiated services. 

Future-Oriented Evolution
Radio Composer will continue to evolve in response to different stages of network development and differentiated service requirements, and exploits the best way to combine new services and application scenarios to offer best experience and optimal efficiency. Moreover, Radio Composer can be driven by more intentions, such as energy-saving intention for carbon neutrality and the comprehensive integration of multiple intentions, like experience, efficiency and energy efficiency. With the introduction of cross-domain information, the joint orchestration of consumers and industry segments will be further strengthened to implement more flexible coordination of user experience, network efficiency and other intentions within a single network, thus facilitating social digital transformation and 5G business prosperity.