The Rising Demand for Increased Bandwidth
Wireless devices such as smart phones, tablets, and laptops have contributed to the explosive growth in internet traffic over the past few years. An average 4G connection generates 15 times more traffic than a 3G connection, and requires proximally located mobile towers to meet the Signal to Noise Ratio (SNR) requirements of advanced modulation techniques. The phenomenal growth in traffic from mobile devices poses new challenges for service providers (SPs) and network operators in meeting customer needs, without compromising the bottom line. The obvious but costly solution to increased bandwidth demand would be to increase the link capacity. However, this can impact profit margins. In addition, an increase in link capacity from the wireless side may not completely resolve the issues because the available spectrum shrinks with more customers connecting to the mobile tower. This challenge can be mitigated by using the unlicensed spectrum of radio frequency, wherever possible.
An SDN Architecture for Cellular Networks
SDN can effectively mitigate the challenges of present day cellular networks. It offers a logically centralized control plane for the networks wherein the network equipment has only data plane or data plane with basic control plane functionality. The centralized nature of SDN enables better coordination among network elements.
Similarly, SDN can enable common control protocol across diverse wireless technologies for seamless mobility support within and across technologies (WiMAX, 4G LTE, 3G UMTS, and Wi-Fi). In addition, due to its centralized control plane, SDN architecture can give cellular operators greater control over their equipment, simplify network management, and introduce value-added services. Since SDN centralizes the existing distributed control plane and management plane functionality, it enables a significant reduction in control traffic that increases rapidly with the introduction of new services. With SDN, the centralized nature of special data plane features such as rate limiting, traffic monitoring or firewalling can be decentralized into multiple NEs. This creates hotspots in the network and reduces NE cost, as expensive and dedicated hardware is no longer required for each function.
Improving Wireless Cellular Networks with SDN
Today’s cellular wireless networks need to handle the rapidly escalating customer demand for higher bandwidth. As a result, service providers are scrambling to meet customer expectations, without impacting their profit margins. SDN offers tremendous potential to solve the current network issues because of its architectural and cost benefits, enabling service providers to scale operations efficiently while mitigating costs. Although SDN adoption benefits are perceptible, the return on investment of SDN networks and the capex made on existing networks may be the deterrents for its deployment. However, new technological advancements such as 5G, with very low latency requirements, and programmable cities (e.g., Bristol is Open) will act like a tipping point at which the benefits of SDN networks may be too overwhelming to ignore.