# A Novel Approach to Multi-Provider Network Slice Selector for 5G and Future Communication Systems
## 3 Related Work  
The purpose of this section is to contextualize the slice selection problem in the scenario of heterogeneous mobile networks (e.g., 5G and Wi-Fi 6) to support the expected contribution of this work in Section 5.1. Several solutions have been proposed to evaluate and select the best slice, considering the QoS requirements for telephony and data services. In general, the literature suggests approaches that consider the following situation: Given a set of criteria or network parameters, the works verify at any given time and among the available slices, which better fits the user needs, supporting network exchange (handover process) for the mobile [4; 5; 17; 18]. In this case, the process of choosing the slice is subject to a number of criteria. A higher number of mobile devices, as well as the variety of services in the vertical slicing model, require the optimized development of an appropriate logical architecture, which allows scalability, energy efficiency, simplification of network functions, and provides a business model (CAPEX and OPEX) that uses the computational infrastructure in operation. Thus, the Network Slicing architecture, with a well-defined Slice Selection service, emerges as the main solution for next-generation mobile networks [5; 19; 20]. Most papers focused on strategies that offer telecommunications operators mechanisms that can provide and control resources for each virtual instance. This includes customization to meet the specific requirements of users in a pre-defined structure of the allocation of resources, that is, without the decision of the choice of the slice being passed by the end-user, and ignoring the type of RAN to which it is linked. These points raise interesting questions that need to be evaluated, such as the End-to-End (E2E) model in NS environments; the guarantee of continuity of services in a roaming NS architecture without the interruption of active services and with guaranteed stability in the delivery of data in scenarios with medium and high mobility; interoperability between different network slice architectures under different administrative domains; security in the transmission of sensitive data; and the migration of all physical network functions to logical networks (Network Function Virtualization--NFV) abstractions [1; 3; 16; 21]. According to [1; 22; 23; 24], the issues listed above are important and have motivated several research laboratories and institutions to seek to standardize the strategies and solutions pointed out so far to create standards for the industry. Those institutions and working groups include but are not limited to the Internet Engineering Task Force (IETF) [25], Next Generation Mobile Networks (NGMN) [26], Open Networking Foundation (ONF) [27], 3 rd Generation Partnership Project (3 GPP) [28], and the European Telecommunications Standards Institute (ETSI) [29]. Therefore, new proposals of approaches, as well as modifications to existing architectures, constitute an open field from the point of view of researchers and the market [5]. An issue that has arisen in some countries is whether the slicing of the 5G network will be consistent with the network neutrality regulations. Some say that the practical implications for current open Internet rules are speculative at this stage concerning 5G. That is because the evolution of the different 5G elements, such as NS, depends not only on the occasional technological capabilities but also on the market demand, the degree of competition, the commercial strategies, and so on [30]. There are several contributions in the literature for admission control, resource allocation, and billing mechanisms in virtualized wireless networks [31; 32]. However, the discussion remains open in the scientific community in terms of automated mechanisms for slicing and monetization in 5G [33].