# QoS Management and Flexible Traffic Detection Architecture for 5G Mobile Networks
## 2 General Architecture Considerations and Related Works
Additionally, the proposed architecture is focused on the reduction of delay in the specific QoS flow creation (on-demand), and changes are not required in the OpenFlow protocol used. 4G eNB or 5G gNB are key elements in the proposed architecture. These elements keep the 4G or 5G mobile access and control interfaces, but incorporate OpenFlow functionality at the same time (these modified elements are called in this work OF-NB). In the proposal, the Controller is responsible for creating all flow entries required to link the traffic between the OF-NB radio interfaces and the backhaul interface. Figure 1 also shows that the OF-NB can optionally implement different types of mobile access interfaces [27; 28; 29], as 4G E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) or 5G NG-RAN (Next Generation Radio Access Network) interfaces. This work is focused on the backhaul and mobile core network and can be adapted to different access types. As an example of specific QoS flow creation, in Section 3.4, the radio bearer creation is shown using the standard LTE (Long-Term Evolution) procedures with E-UTRAN Uu interface and S1-MEE (Mobility Management Entity) interfaces, as well as the interaction with 4G UE. In [30], a software-defined architecture for next-generation (5G) wireless systems, namely SoftAir, was introduced. More specifically, the concepts of network function cloudification and network virtualization were exploited, decoupling the radio interface implementation from the base station control, which allows the independent evolution of radio technology. The work in [30] also proposed two levels to detect QoS requirements: (i) the local traffic classifiers placed in a software-based centralized base station at the network edge and (ii) the global traffic learner implemented by the network Controller. Our proposal implements two QoS traffic detection levels as well, but in a significantly different way: (i) traffic detection at OF-NB using standard OpenFlow tables and (ii) specialized software detection devices that can be implemented in a distributed way (not in the Controller), increasing the solution scalability. Furthermore, the data plane proposed here is  
Figure 1: Architectural proposal, visualizing the 4G and 5G mobile control entities. UDM, Unified Data Management; HSS Home Subscriber Server; VM, Virtual Machine; PCF, Policy Control Function; PCRF, Policy and Charging Rules Function; SMF, Service Management Function; PGW-C, PDN Gateway Control; AMF, Access and Mobility Management Function; MME, Mobility Management Entity; SDD, Service Detector Device; OF, OpenFlow; NB, NodeB; E-UTRAN, Evolved UMTS Terrestrial Radio Access Network; UMTS, Universal Mobile Telecommunication System; Uu, UMTS air interface; NG-RAN, Next Generation Radio Access Network; UE, User Equipment. implemented as completely distributed, and the traffic to be routed does not require being sent to a central device. Finally, the detection process is performed at the same time as the routing process. A device-to-device communication algorithm able to enhance user quality of experience, by improving the success probability of Internet access in both downlink and uplink directions, was presented in [31]. The Controller is not only able to manage the base station, but also manages the UEs, which can be configured to act as a traffic relay for another UE when the neighboring base stations are congested. Differently, our work is not focused on the mobile access network, but on the mobile backhaul and core network, and the Controller domain is extended to the base stations. The interaction between OF-NB and UEs is performed using 4G standard access interfaces or future 5G access interfaces, and the incorporation of SDN protocols in the UEs is not required, increasing the feasibility of the solution. In particular, a step-by-step procedure is described in order to create an end-to-end path with the QoS requirement. The proposed mobile architecture uses Multiprotocol Label Switching (MPLS) to implement the data plane.