OpenRadio and Software Defined Cellular Wireless Networking

Mobile wireless networks today are faced with two conflicting trends.

To cope, future wireless network deployments have to get dense. This is motivated by a simple observation: The surest way to increase per-user capacity is to make cells small and bring the basestation closer to the mobile client, since this improves per link SNR and reduces the number of users per cell. Some industry estimates suggest basestation density will have to increase by 20× to handle the exponential traffic growth.

However, current network architectures are ill-equipped to support a dense and dynamic wireless infrastructure. First, since it will be impossible to obtain regularly placed cell sites for an infrastructure with 20× higher density, basestations will be deployed wherever possible in a chaotic fashion. However, a chaotic and dense wireless deployment will be very complex to manage, since it will experience highly variable loads and unpredictable inter-cell interference among other things. Finally, a dense infrastructure is very expensive to deploy and operate. Current deployments are unaffordable except to the largest operators, so a deployment with 20× more basestations will likely be infeasible even for the largest operators.

Our larger research goal is to design a novel network architecture called OpenRadio for future dense and adaptive wireless infrastructure. At its core, OpenRadio aims to apply the software defined networking (SDN) approach to design systems and abstractions that simplify the deployment and management of dense cellular wireless networks. The agenda is ambitious and involves several components, including developing the programmable basestations and network infrastructure (akin to programmable switches for wired networks), developing a wireless control plane (akin to NOX for wired) and capabilities to slice the wireless network. In the next 18 months, as part of this research agenda, we plan to focus on the first aspect:

Programmable Wireless Data Plane

A basic requirement for a SDN based network architecture is a programmable wireless dataplane. Like programmable switches for wired SDN architectures, we plan to design a high performance, programmable wireless basestation (BS). The same programmable BS can be customized to support LTE, WiMAX or WiFi. It will provide further the following properties: