Adaptable Channel Testbed for Investigating On-the-move Wireless Nodes (ACTION)
ACTION is a comprehensive, real-time platform used to analyze the performance of wireless networks with stationary or mobile nodes. A test-bed or “fictional” approach is essential due to the challenge and cost associated with live field-testing to capture network performance for high-speed (> Mach 4) network elements. ACTION provides a controlled simulation environment to model mobile nodes and the cellular-like network area through which they move. This approach allows for the real-time collection of network performance statistics and allows for sophisticated analysis of complicated wireless networks, without actually radiating over the air.
Dynamic characteristics of the signals emitted and received by a live mobile node include amplitude, phase, and frequency offset (e.g. Doppler shift). Hardware and software devices that control and model these signal components form the heart of the ACTION simulation. Network analysis software is also used to collect statistics on packet errors, bit errors, and link availability. Base stations provide the network “backbone” to the mobile node. The antenna ports of the base stations are wired into the Amplitude, Phase, and Frequency Control (APFC) module which controls the signal between the base stations and the simulated “mobile” node. A PC connected to a Labview® control device drives the APFC. The simulated mobile node is also connected to a PC that controls data flow and measures network statistics such as bit error rate, packet error rate, and latency. Additionally, outside signal interference sources can be inserted into the signal path with little modification to ACTION.
ACTION is expandable and is designed to support up to three physical base stations and one physical mobile network user node. However, through the logical re-assignment of base station roles within the fictitious wireless network, the fictitious network infrastructure can assume any size (i.e. ACTION can model a single mobile node moving through any arbitrary wireless network deployment). Multiple mobile nodes can be accommodated through the addition of APFC modules and additional output control cards.
This invention has a working, albeit primitive, prototype. The commercial application is significant, as it allows network operators to test virtually limitless scenarios with a variable number of base stations and mobile nodes. ACTION can be used to test network and transport layer protocols through commercial IEEE 802.11b and IEEE 802.11g wireless LANs under a variety of wireless channel conditions. The invention may also be used to ascertain the performance of the IEEE 802.11b and IEEE 802.11g standards themselves in a variety of wireless channel conditions. The IEEE 802.11a standard can be readily accommodated through the addition of a block downconverter/upconverter to adjust frequency bands to that accommodated by the APFC devices, since the ACTION simulation software can account for the actual difference in frequency band through simulation and signal manipulation techniques. Furthermore, the ACTION concept could be easily applied to Bluetooth and European wireless communications technologies through trivial changes in connector types and physical equipment interfacing. Network administrators can use a tool such as ACTION to make detailed performance predictions for a single mobile network user. This is considered very attractive where precise knowledge of the outcome of the experiment or exercise is desired due to the potential consequences (e.g. an expensive system failure or unintended loss of life). Competing technology does not provide for such a flexible or robust package. Furthermore, competing technology does not allow for the emulation of multiple network links at a cost comparable with that of the ACTION prototype.CONTACT:
Dr. G. R. Jacobovitz
Phone: (443) 778-9899