Virtual Base Station Pool: Towards A Wireless Network Cloud for Radio Access Networks

The mobile Internet has seen tremendous progress due to the standardization efforts around WiMAX, LTE and beyond. There are also early trends towards adoption of software radio and a growing presence of general purpose platforms in wireless networking. Such platforms are programmer friendly and with recent advances on multi-core and hybrid architectures, allow signal processing, network processor class packet processing, wire-speed computation and server-class virtualization capabilities for software radio realizations of 3G and 4G wireless stacks. Software radio over IT platforms will enable the virtualization of base stations and consolidation of virtual base stations into central pools (a local "cloud site") with fiber connectivity to towers, which we call a Wireless Network Cloud (WNC). A Virtual base station (BS) pool supporting multiple BS software instances over a general OS and IT platform is an important step towards the realization of the larger WNC concept. This paper introduces the first TDD WiMAX SDR BS implemented on a commodity server, in conjunction with a novel design of a remote radio head (RRH). We also present the first working prototype of a virtual BS (VBS) pool, exploring the systems challenges in supporting a VBS pool on multi-core IT platforms. The results from our VBS pool prototype for WiMAX verify that these solutions can meet system requirements including synchronization, latency and jitter.