Future cellular networks will be dense and require key traffic management technologies for fine-grained network control. The problem gets more complicated in the presence of different network segments with bottleneck links limiting the desired quality of service (QoS) delivery to the last mile user. In this work, we first design a framework for software-defined cellular networks and then propose new mechanisms for management of QoS and non-QoS users traffic considering both access and backhaul networks, jointly. The overall SDN-LTE system and related approaches are developed and tested using network simulator in different network environments. Especially, when the users are non-uniformly distributed, the results shows that compared to other approaches, the proposed load distribution algorithm enables at least 6 and 23 increase in the average QoS user downlink throughput and the aggregate throughput of 40 users with lowest throughput (edge users), respectively. Also, the proposed system efficiently achieves desired QoS and handles the network congestion without incurring significant overhead.
@cite_15: Due to inflexibility, design and control of existing networks are very complex. Therefore, SDN aims to separate control and data planes clearly, which is an innovative and effective approach to this problem. With SDN, a service provider can adjust the settings of a network according to various requirements dynamically and in a timely fashion. This feature is especially suitable for a wireless scenario with dynamic and unstable changing situations. Meanwhile, because various algorithms, such as traffic forwarding and quality of service, can be operated by a central controller, SDN is a natural optional technique for WNV. In this article, we illustrate the framework for combining SDN and WNV, review state-of-the-art related work, and discuss the challenges for future study.
@cite_16: Despite the research community's extensive research towards the advancement in cellular communications, it nevertheless remains an irresolvable problem until now to tackle link congestion. Congestion in communication links may be due to traffic overload and or link failures and or node failures when we consider the wireless backhaul infrastructure of the network operators. While the physical layer technologies have evolved providing high-capacity air-interfaces, network devices have improved in computational power and a vast amount of exciting applications have emerged, the backhaul network architecture in its structure has not seen much change from its early days. With this as starting point, in this paper we claim that with a few "intelligent" design changes within the backhaul architecture of network operators incorporating OpenFlow protocol within the access and aggregation nodes, tackling congestion in communication links, thus becomes achievable.
@cite_1: Self-Organising Network (SON) use cases are seen as key enablers of efficient Long Term Evolution (LTE) system operation. Mobility Load Balancing Optimisation (LB) is a prominent SON use case defined by 3GPP with the scope of balancing the load in a given coverage area by reconfiguring the handover thresholds. When overload is detected at a given cell, the LB reduces the handover thresholds of those user equipments that can be redirected to the underutilised neighbouring cells. This mechanism improves the user plane performance in the overloaded cell. Despite the potential benefits, the available LB mechanisms have two major deficiencies, both of them causing user experience degradation: on the one hand, they tend to overestimate the load on the air interface, resulting in unnecessary handovers; on the other hand, they are either transport agnostic or have limited capability to consider the transport load during their decision process. This paper provides an overview of the LB related problems and proposes an improved solution including accurate evaluation of the radio load and a transport aware mechanism for end-to-end optimisation. The performance of the solution was evaluated by simulations.
An enhanced mobility management approach in traditional LTE network is proposed in @cite_1 , where the handover offset is tuned for the overloaded cells. A major setback of using it is that it presumes that the last mile link connecting the BS to the core network is the bottleneck. However, this is not always true, since the backhaul network usually has a ring topology @cite_16 where the bottleneck can exist anywhere in the network. @cite_15 author outlines a framework that enables efficient traffic forwarding and QoS control within a wireless network by using SDN concepts.