Scaling WLANs in Spectrum, User Density, and Robustness

This NSF-funded project is designing the next generation of Wireless Local Area Networks (WLANs) that will meet the ever-growing demands for more spectrum, higher densities, and higher degrees of robustness, moving closer towards the vision of multi-Gigabit-per-second (Gbps) connectivity everywhere. Via a combination of physical and link layer innovations, the project will design the first S-T (Sixty Gigahertz to Terahertz) WLAN offering multi-Gbps and Terabit-per-second (Tbps) data rates, supporting both downlink and uplink multi-user multi-stream communication, and providing robust always-on connectivity.



A Millimeter-Wave Multi-Layer WLAN Architecture for Multi-Gigabit, Always-On Connectivity

This NSF-funded project is developing a Millimeter-Wave multi-layer architecture for general purpose multi-Gigabit WLANs that will offer always-on connectivity in the home/enterprise environment but an order of magnitude higher throughput than today’s 2.4/5 GHz WLANs. The proposed architecture is developed in a systematic, bottom-up fashion, starting with an understanding of the Millimeter-Wave channel and its impact on higher layer performance and gradually moving up the layers of the network stack.

Power-performance tradeoffs for Mobile Devices in Next Generation WiFi Networks

This NSF-funded project seeks to understand the performance-power tradeoffs of next generation WiFi (802.11n/ac) on power-constrained devices, and develop measurement-based models to capture these tradeoffs. Additionally, the project performs power analysis at the system and application levels through a thorough power modeling and measurement, and combines it with the WiFi power models in addressing power-performance tradeoffs with considerations at multiple levels. The developed power models will guide the design of novel power management, rate adaptation, and network management protocols that will allow mobile devices to realize the maximum possible performance benefits while minimizing the power consumption and the impact to the other WLAN clients.

X60: A Cross-Layer Reconfigurable Multi-Gigabit WLAN Testbed at 60 GHz

This NSF-funded project is building X60, the first software defined based 60 GHz testbed that offer high level of reconfigurability at the PHY, MAC, and network layer while supporting channel widths and speeds commensurate to those of the 802.11ad standard. The X60 nodes are based on the NI mmWave Transceiver System from NI and equipped with 12-element phased antenna arrays from SiBeam that can be configured in real-time.

Routing in 802.11n/ac mesh networks

We are designing new routing metrics for the next generation of wireless mesh networks (WMNs) consisting of 802.11n/ac links. Our experimental studies in UBMesh revealed that the throughput gains of state-of-the-art link quality-based routing metrics (ETX, ETT) over the hopcount metric in legacy WMNs do not carry over in 802.11n WMNs and the large link throughput gains of 802.11n over 802.11a/b/g do not translate into multihop throughput gains. We found that popular probing techniques for link loss rate and bandwidth estimation yield poor accuracy in 802.11n WMNs due to the new features introduced at the underlying MAC/PHY layers. We are currently exploring clustering techniques to reduce the probing overhead.


UBMesh is an experimental 802.11a/b/g/n/ac wireless mesh network testbed at UB. It currently consists of 21 static wireless routers deployed on the third floor of Davis Hall at UB. Additionally, laptops and smartphones are used as mobile clients. The deployment of UBMesh helps us evaluate the performance of legacy 802.11a/b/g routing and transport layer protocols over 802.11n/ac mesh networks, to understand their limitations, and to design new protocols to harvest most of the gains promised by the 802.11n/ac technology.

Motion Detection in WLANs using PHY Layer Information

In this project, we demonstrate that it is possible to enable fine-grained human motion detection on commodity WiFi devices by exploiting PHY layer information available from today's WiFi chipsets. In the first part of the project, we leverage Channel State Information (CSI) and Time-of-Flight (ToF) values, available from commodity APs, without any software modifications on the client side, to detect different client mobility modes, and design a number of motion-aware wireless protocols. In the second part of the project, we leverage the Angle-of-Arrival (AoA) values of incoming wireless signals at the mobile device to track the detailed trajectory of the user's hand and design WiDraw, the first hand motion tracking solution based on wireless signals, that can be enabled on existing mobile devices using only a software patch.

CANSAS: Crowdsourcing Access Network Spectrum Allocation using Smartphones

This project introduces the concept of crowdsourcing access network spectrum allocation using smartphones (CANSAS). CANSAS utilizes the rapidly-growing number of smartphones, which are always on but mostly idle, to perform triggered and periodic observation of both their own wireless performance and that of other nearby active terminals. Channel measurements from (idle) smartphones are used as inputs to new radio resource management algorithms which improve spectral efficiency through dynamic allocation of channels and transmission powers, and also through scheduling uplink and downlink transmissions.

Routing in cognitive radio networks

Although a large number of routing protocols for CRNs has been proposed over the past few years, the design of these protocols suffers from two main limitations: (i) the majority of the proposed protocols have not been evaluated against each other but only against some “strawman” protocol without sensing capabilities. (ii) Most of these protocols have only been evaluated in simulators, under a number of unrealistic assumptions (e.g., multiple channels available on every node, availability of an always-on control channel for coordination, perfect spectrum sensing capabilities, perfect timing synchronization, etc.). -->We are interested in the design and implementation of practical CRN routing protocols that can be deployed over off-the-shelf hardware. As a first step towards this direction, we conducted the first empirical performance study of three state-of-the-art CRN protocols using both a simulator (ns-2) and a testbed based on the USRP2 platform, under the same realistic set of assumptions. Our study demonstrated the need for self-adaptive protocols that choose different link/path routing metrics in different scenarios, in an online manner; we are currently working towards this direction. Our design will also be guided by the new 802 standards on cognitive wireless networking (802.22 for wireless regional area networks and 802.11af for white space WiFi).

Analog network coding in underwater acoustic sensor networks

In this project, we first designed CE-CDMA, a collision-enabling direct-sequence code-division multiple-access scheme for multi-hop underwater acoustic sensor networks (UW-ASNs). Our simulations and experiments in Lake LaSalle at UB demonstrate that for a 1-2dB tradeoff in signal-to-noise ratio (SNR) the proposed scheme can potentially improve the channel utilization of a unidirectional multi-hop linear network by up to 50%. We then designed a secure underwater communication scheme JANC (Jamming through ANC) that relies on cooperative friendly jamming through CDMA-based analog network coding (ANC). Our results demonstrate that, for a given energy budget, the proposed scheme can guarantee much higher bit error rate (BER) at Eve, while creating minimal BER disturbance at Bob, compared to the AN-aided approach.