# Development of Intelligent Core Network for Tactile Internet and Future Smart Systems
## 2 Related Works  
Moving from traditional Evolved Packet Core networks to next generation of cellular systems requires the involvement of a smart controller at the core of the network. The controller manages all of the operations inside the network. In this part, we present the main works that are concerned with the development of a centralized controller for delay sensitive networks. We analyze each work and provide similarities and differences between each work and our system. In [20], the authors present a SoftCell cellular system that enables the system operator to achieve service policies at high levels. The proposed system reduces the forwarding table's size and aggregates traffic in multiple dimensions at various switches in the network. The system employs an access switches at the base stations, which are software switches. Access switches can classify packets that have arrived at the base station and handle the required state and bandwidth. SoftCell employs the components of the traditional Evolved Packet Core cellular network with a controller at the core network with certain functions. The controller installs the switch rules and implements the signaling rules that are used between hosts. The system is suggested for deployment to the core of LTE existing networks. The system improves the flexibility and scalability of the LTE cellular system. The main problem with the system is the capability of the core network controller and it still mainly depends on the gateways (SGW, PGW) at the core network. Recently, there are a number several approaches speak about employing SDN at the core network of cellular system. These are the most relates works. In [21], the problems and transport challenges to realize the 5G system. The authors suggested a structure for the core network based on SDN and employ the edge computing. In [22], a network coding is developed and employed with SDN to reduce Latency in 5G cellular system. The network coding is achieved through a software router that acts as a virtual network function. The main problem with the system is that they did not consider the MEC; however, they mainly concerned with the coding and SDN. The system is mainly introduced for 5G and the Internet of Things [23, 24, 25]. In [26], an optimized framework for a virtual network is introduced to reduce end-to-end delay in LTE-A cellular networks. A central controller is employed in the core network and used mainly for slicing the physical resources. The authors employ Virtual Network Embedding (VNE) algorithm to map the virtualized networks on substrate network. The system model consists of destination edge routers and only single gateway. The edge router is responsible for the mobility management based on a distributed mobility management (DMM) scheme that is applied to the system. The system mainly concerned with the path optimization and network virtualization. The system achieves better latency performance and increases the user mobility. MEC is not involved in the structure and the system may be seen as a modification for the LTE-A cellular system. In [27], a 5G based SDN architecture is introduced, with the dense deployment of small cells. Employing small cell concept raises the challenge of frequent handover and the latency dedicated with the handover process. Authors provide a system structure to overcome these challenges by using SDN controller at the core network. Another main function of the controller is the allocation of radio access resources and overcoming challenges that are associated with the deployment of multiple radio access technologies. The system is mainly concerned with the problem of latency of the handover process. SDN controller defines three types of programmed interfaces that make the system able to predict the user is movement, and thus handle the handover process in less time. Each work of the previous works employs a controller at the core network for certain functions. All of these functions provide system with a high efficiency in terms of bit rate and latency.