Toward Software-Defined Cellular Networks

Abstract

Abstract-Existing cellular networks suffer from inflexible and expensive equipment, complex control-plane protocols, and vendor-specific configuration interfaces. In this position paper, we argue that software defined networking (SDN) can simplify the design and management of cellular data networks, while enabling new services. However, supporting many subscribers, frequent mobility, fine-grained measurement and control, and real-time adaptation introduces new scalability challenges that future SDN architectures should address. As a first step, we propose extensions to controller platforms, switches, and base stations to enable controller applications to (i) express high-level policies based on subscriber attributes, rather than addresses and locations, (ii) apply real-time, fine-grained control through local agents on the switches, (iii) perform deep packet inspection and header compression on packets, and (iv) remotely manage shares of base-station resources.

Future RAN Architecture: SD-RAN Through a General-Purpose Processing Platform

“…The major issue is to create appropriate mapping of the existing network functionalities to the decoupled control and forwarding planes. While a lot of the work is done for wired or optical networks, some proposals are also presented for cellular SDN architecture [3] [6]. For the radio access part of the mobile communication system, two fundamental questions are as follows, i.…”

“…In SDN, control plane relates to all control logic required to manage the network, connections, and forwarding the data packets. From SDN's perspective, base stations, serving gateway (S-GW), and packet gateway (P-GW) of LTE architecture are also performing some control plane functions along with data forwarding in addition to the designated control plane nodes MME (Mobility Management Entity), HSS (Home Subscriber Server), and PCRF (Policy Control and Charging Rules Function) [6]. Although not within the scope of SDN, but it is worthwhile to discuss an extreme approach of re-designing radio access architecture, i.e., the Cloud RAN [5].…”

“…Where the control plane will be located? The centralized controller in the state-of-the-art proposals of SD-RAN, either resides in the core network [6] or in a centralized data centre [3]. The design in [6] tries to push all the control plane functionality into a centralized controller in the core network and proposes the use of local switch agents for scalability.…”

“…The centralized controller in the state-of-the-art proposals of SD-RAN, either resides in the core network [6] or in a centralized data centre [3]. The design in [6] tries to push all the control plane functionality into a centralized controller in the core network and proposes the use of local switch agents for scalability. The proposition in [3] is focused towards refactoring the control plane into a virtualized big base station controller for a geographical area and local controllers within each base station for latency sensitive decision making.…”

Adapting Downlink Power in Fronthaul-Constrained Hierarchical Software-Defined RANs

“…The centralized controller can thus optimize the network performance with the global view of the network and adapt radio resources to the network dynamics, i.e., the channel quality variations and the mobile traffic fluctuations from mobile users (MUs). However, the problems with the software-defined RAN concept lie in the inherent latency due to the totally centralized control plane and the need of large-capacity fronthaul links to connect the BSs and the controller [4], [5]. It thus becomes necessary to design a more flexible software-defined RAN architecture.…”