Rice’s University’s WARP is a scalable and extensible programmable wireless platform, built from the ground up, to prototype advanced wireless networks.


ARGOS - Argos is a novel many-antenna beamforming architecture with decentralized beam weight calculation and internal calibration for implicit beamforming. Argos project pushes MU-MIMO to its limits, scaling up the number of antennas in wireless systems to a point previously thought impossible. This enables us to achieve enormous capacity and power gains, and discover the true real-world limits of MU-MIMO. The capacity of traditional single-user wireless systems is exclusively limited by the available spectrum and transmission power. Recent developments in information theory, however, have shown that such capacity limitations can be overcome by improving the spatial reuse efficiency through multi-user multiple-input multiple-output (MU-MIMO) technology, or its special form called multi-user beamforming (MUBF). With MUBF, a base station employs multiple antennas to simultaneously send independent data streams to multiple users, tremendously increasing the aggregated network capacity. In the Argos project we develop new techniques that enable hundreds of antennas to be deployed on base stations, resulting in enormous network capacity gains. We use the WARP platform to build the first real-world prototype of a many-antenna MUBF base station and experimentally evaluate its performance. Our research demonstrates the feasibility of many-antenna base stations, and is designed to motivate industry adoption of this promising technology in the near future.

Interference-Aware Cooperation via Structured Codes: Creating an Empirical Cycle - Interference is one of the last unexplored frontiers in wireless networks. Modern wireless systems treat interference between users as a source of noise to be avoided. However, an emerging body of work, ranging from interference alignment to physical-layer network coding, has indicated that tremendous gains may be possible by embracing interference as an opportunity for cooperation. Although these interference-aware schemes have generated a great deal of excitement in the research community, the promised gains have so far been relegated to the theoretical realm. This is in part due to their perceived sensitivity to channels non-idealities as well as the dearth of low-complexity coding algorithms that can approach the performance predicted by information theory. The primary aim proposal is to create a robust, practical foundation for next-generation wireless networks that can harness the gains of interference-aware cooperation in terms of throughput, energy efficiency, and reliability. The research agenda is designed according to de Groot’s concept of the empirical cycle. Specifically, information theory will be used to inspire coding algorithms which will be in turn implemented on the Wireless-Open Access Research Platform (WARP) to assess their practical feasibility. The research directions are organized into three thrusts: -Constellations, Codes, and Computation. -WARP: An Experimental Sandbox. -Model Building and Robust Compute-and-Forward. This research is supported by a grant from National Science Foundation (NSF).

Cross-Layer Modeling and Design of Energy-Aware Cognitive Radio Networks - Minimization of energy consumption is critical to developing green, sustainable technologies for cognitive radio terminals that are able to connect to networks that operate on different frequency bands with a variety of air interfaces. At the same time, flexibility and configurability of the implementation at the RF, baseband, and MAC layers, with cross-layer modeling and control, will be important to realize the efficiency potential of spectrum sharing. The flexible use of RF spectrum over a multitude of different frequencies requires advanced configurable radio devices. Receiver configuration based on programmable paradigms has received attention in recent years but practical solutions are still lacking, especially for the radio frequency (RF) components. At the same time, programmable baseband computation and related design chains have significantly developed. This enables more efficient control of computational resources and hardware. The software based adaptive configuration of radio frequency chains is still in its infancy, but it is a key ingredient of the frequency agile radios needed for cognitive devices and flexible RF spectrum use. The key novelty is in the development of systematic methods for design, implementation, and integration of configurable RF chains, and in the development of dataflow methods for formal analysis and optimization of these new capabilities. This research is supported by a grant from National Science Foundation (NSF).

WiPhyLoc8: Dynamic WiFi Positioning using Physical Layer Parameters for Location-based Services and Security - WiFi technology has emerged as an ubiquitous networking technology, allowing us to work, play and communicate. Advances in accurate WiFi location are vital to provide support for next generation indoor navigation, network security, emergency evacuation and commercial services. Current technologies cannot suffice as GPS signals are too weak to penetrate buildings and Received Signal Strength Indicator (RSSI)-based solutions provide accuracies of 2-3m in 50% of cases in favorable conditions and much less in challenging indoor environments. In fact, even the promised accuracy of 2m can be the difference between being your own office and your neighbor’s! Moreover, the human body severely attenuates RSSI reducing accuracy for mobile users. While UltraWide Band (UWB) can provide 10-30cm accuracy, it will not be incorporated in mass market, WiFi-based smartphones. The preferred approach is to enhance the precision and robustness of WiFi-based localization systems. New WiFi localization algorithms, Spotlight and LocationSync will be created that will achieve sub-meter accuracy in real-world indoor environments. Spotlight will utilize multiple antennae at the Access Point (AP) and beamsteering to obtain a Direction Of Emission (DOE) - Receive Signal Strength (RSS) signature from each AP, thereby reducing the impact of multi-path and occlusion. This research is supported by a grant from National Science Foundation (NSF).

“Distributed" Network Information Theory: Local View Capacity - Mismatched and incomplete network state information, aka local view, is a reality in all wireless networks. Yet, there have been no effort to develop information theoretic capacity of networks with a local view. This research is supported by a grant from National Science Foundation (NSF).

Full-duplex Wireless Communications: Prototypes, Protocols and Theory - In 2010, we re-purposed off-the-shelf MIMO radios used in WARP platform to develop a single-channel full-duplex wireless communication system. Combining a mix of experiment-driven data modeling and information-theoretic analysis, we have shown that full-duplex is a definite reality for short to medium range communications. This research is supported by a grant from National Science Foundation (NSF).

Distributed Cooperative Communications: Framework and Real-time Implementations - We are developing a systematic framework to construct implementable distributed cooperative communication protocols, which balance network knowledge, spatial reuse and overall network capacity. This research is supported by a grant from National Science Foundation (NSF).

Directional Communication on Mobile Devices: Feasibility and Data-driven Analysis - Much like full-duplex was considered largely impossible, directional communication on mobile devices has also been considered impossible before due to their small form-factor to fit traditional directional transmissions. This research is supported by a grant from National Science Foundation (NSF).

MoodSense - Can your phone sense your mood?We are currently recruiting iPhone users for a 2-month long study to investigate the possibility of training a phone to recognize certain moods from phone interaction patterns. The study involves the installation of a mood input application, called MoodTrack, and a phone usage collection tool, called LiveLab. Both are detailed below. While private data will be kept anonymous, the results of the study will be academically analyzed and reported. If you have an iPhone that runs iOS 4.0 or higher and are willing to jailbreak the phone, you are eligible for our study. Early results from our first user study can be found in our PhoneSense 2011 Workshop paper.