This project is aimed at a third-generation equipment upgrade for the ORBIT (Open Access Testbed for Next Generation Wireless Networking) testbed which has been operated by Rutgers University as a community resource since 2005. The ORBIT testbed, which researchers access remotely over the Internet, provides a flexible, scalable and reproducible platform for conducting wireless network experiments. ORBIT lowers the barrier for experimentation in the area of radio and wireless technology and thus improves education and research productivity in the field. The goal of this project is to extend the testbed to incorporate two key new capabilities: (1) LTE (Long Term Evolution) radio access, to support realistic evaluation of future mobile data services, and (2) "cloud radio" processing to enable experimental studies of emerging "5G" radio access technologies. The proposed testbed enhancements will help accelerate the pace of wireless/mobile technology development by facilitating evaluation of emerging radio technologies and network architectures such as dynamic spectrum access, cooperative MIMO (multiple input multiple output) and heterogeneous cellular networks. More specifically, the LTE and radio cloud capabilities to be added in this project will enable the study of techniques for enhancing wireless system capacity, helping to address the important societal problem of spectrum scarcity as mobile data usage continues to grow exponentially.
The ORBIT upgrade proposed here involves two major enhancements to the testbed. First, both the radio grid emulator and the outdoor ORBIT campus network will be upgraded to incorporate LTE in addition to the existing WiMax capability. LTE is rapidly being deployed in 4G cellular systems worldwide, and it is important to enable the research community to use this access technology for realistic mobile network experiments. LTE capability will be added to the outdoor ORBIT network by retrofitting a commercial base station to be controllable through the ORBIT management framework (OMF), while LTE on indoor nodes will be implemented in software running on available SDR platforms. Second, the radio grid's backend will be upgraded with a unique combination of FPGA and CPU based "software radio cloud" that will increase processing speeds by two orders-of-magnitude. The proposed radio cloud is designed as a hierarchically organized high-performance system which includes fast CPU-based servers, FPGA co-processors and "thin-client" software-defined radio nodes all connected together by a fast and programmable switching backplane. The system will include nearly 16 compute server blades (each with rated computing capacity of 700 GIPS), a large FPGA-based centralized co-processor array, a total of about 48 software defined radio (SDR) client nodes and about 128 x 10Gbps OpenFlow switch ports for connectivity. Examples of experiments that will be enabled include LTE-WiFi interworking, LTE-based mobile cloud services, wideband spectrum sensing and dynamic spectrum access algorithms, massive MIMO (multiple input multiple output) and cooperative PHY, cellular cloud RAN (radio access network) and virtual wireless networks. LTE capabilities will be released during year 1 of the project, and a first version of the radio cloud will be released in year 2, followed by an updated version in year 3.
