CSE 550
gshyamcs.washington.edu
Areas of interest: 

Networks, wireless, mobile and ubiquitous computing, sensing, security and privacy

AllSee

Existing gesture-recognition systems consume significant power and computational resources that limit how they may be used in low-end devices. We introduce AllSee, the first gesture-recognition system that can operate on a range of computing devices including those with no batteries. AllSee consumes three to four orders of magnitude lower power than state-of-the-art systems and can enable always-on gesture recognition for smartphones and tablets.

Ambient Backscatter

As computing devices become smaller and more numerous, powering them becomes more difficult; wires are often not feasible, and batteries add weight, bulk, cost, and require recharging/replacement that is impractical at large scales. Ambient backscatter communication solves this problem by leveraging existing TV and cellular transmissions, rather than generating their own radio waves. This novel technique enables ubiquitous communication where devices can communicate among themselves at unprecedented scales and in locations that were previously inaccessible.

WiSee

WiSee is a novel interaction interface that leverages ongoing wireless transmissions in the environment (e.g., WiFi) to enable whole-home sensing and recognition of human gestures. Since wireless signals do not require line-of-sight and can traverse through walls, WiSee can enable whole-home gesture recognition using few wireless sources (e.g., a Wi-Fi router and a few mobile devices in the living room).

MIMO Cognitive Systems

This project presents TIMO, the first WiFi receiver that can decode in the presence of high-power unknown cross-technology interference. Traditionally, researchers have addressed cross-technology interference by dynamically searching for and switching to unused frequencies. We approach the problem from a different perspective: can one operate in already used frequencies in the presence of potentially unknown interferers? We build a new cognitive framework for the unlicensed band which allows multi-antenna devices to work in used frequencies.


Random Access MIMO Networks

This project presents 802.11n+, the first fully distributed random access protocol that allows nodes to contend not just for time, but also the concurrent transmissions supported by multiple antennae. In n+, even when the medium is occupied, nodes with more antennae can transmit concurrently without harming ongoing transmissions. Furthermore, such nodes can contend for the medium in a fully distributed way. Our testbed evaluation shows that even for a small network with three competing node pairs, the resulting system about doubles the average network throughput.


Password-Free Wireless Security

This project presents tamper-evident pairing, the first wireless pairing protocol that works in-band, with no pre-shared keys, and protects against MITM attacks. The main innovation is a new key exchange message constructed in a manner that ensures an adversary can neither hide the fact that a message was transmitted, nor alter its payload without being detected. Thus, any attempt by an adversary to interfere with the key exchange translates into the pairing devices detecting either invalid pairing messages or an unacceptable increase in the number of such messages.


Securing Medical Implants

Wireless communication has become an intrinsic part of modern implantable medical devices (IMDs). Recent work, however, has demonstrated that wireless connectivity can be exploited to compromise the confidentiality of IMDs’ transmitted data or to send unauthorized commands to IMDs—even commands that cause the device to deliver an electric shock to the patient. The key challenge in addressing these attacks stems from the difficulty of modifying or replacing already-implanted IMDs.


Practical Interference Alignment

This is the first work to demonstrate the practicality of interference alignment, which was considered to be a purely theoretical concept prior to our work. Further, we synthesize interference alignment and interference cancellation, showing that the combination is beneficial in scenarios where neither interference alignment nor cancellation applies alone. Our implementation on software radios demonstrate that for 2-antenna MIMO networks, IAC increases the average throughput by 1.5x on the downlink and 2x on the uplink.


ZigZag Decoding

Collisions are a known problem in wireless networks. The existing approaches address this problem by designing techniques that avoid collisions. This project takes an alternate approach: Instead of trying to avoid collisions, lets embrace collisions. In particular, we present ZigZag decoding, a new WiFi receiver that decodes collisions. The core contribution of ZigZag is a new interference cancellation technique that does not make any assumptions of synchronization, large differences in power, or special codes.