Full Duplex Communication Systems with Reduced Self Interference

Full Duplex Communication Systems with Reduced Self Interference

Mentor(s): Besma Smida

Graduate

Oral Presentation

Recently researchers have proven that full duplex communication is possible and it can outperform half duplex systems -- it doubles the throughput of the system. The key challenge for full duplex communication – that allows users to transmit and receive signals simultaneously on the same frequency -- is self-interference. It is the interference caused by the transmitter antenna to the receiver at the same node. The self-interference signal is billions of times stronger than the desired receiver signal. In this paper, we are using a novel technique of antenna cancellation, using a new antenna design and placement which will in practice, obtain an RF isolation of about 50dB and this reduces the coupling between transmit and receive antenna chains. We also propose active analog and digital baseband cancellation techniques to complement the RF cancellation provided by the antenna design. Antenna cancellation by itself provides 30dB of self-interference cancellation and in combination with analog and digital domains, it provides more than 60dB reduction of self-interference signal. This allows us to implement practical full duplex radios, by letting a node to transmit and receive signals simultaneously on same frequency.

Full Duplex Wireless Communication By Means Of Backscatter Modulation

Mentor(s): Besma Smida

Graduate

Oral Presentation

Given the ever-increasing demand for high-speed data services, modern wireless networks will increasingly require more efficient strategies for use of the available frequency spectrum. One key limit to spectrum utilization efficiency involves the current practice of half-duplex communication, in which a node either transmits or receives a signal in a single channel usage. More efficient strategies for use of the available radio spectrum are needed. Furthermore, communication is asymmetrical and is becoming more so over time. From the view point of traffic symmetry between uplink (mobile to base station) and downlink (base-station to mobile), data traffic started as highly symmetrical with voice services. Overtime, however, it has become markedly imbalanced, with the major growth of new multimedia services being characterized by asymmetric traffic (much higher downlink). Overall traffic patterns are also becoming more asymmetrical because the largest bandwidth demand currently derives from downstream TV and Internet video signals. In this paper, we propose a design for full-duplex wireless communication system, based on backscatter modulation (BM) that is able to efficiently accommodate high downlink traffic. We consider two nodes

Human Activity and Status Recognition Using Depth Data

Mentor(s): Bin Chen

Graduate

Oral Presentation

Automatic activity detection is helpful in human daily lives. The elderly people, patient with mobility problems and other special needed people require real time monitor to prevent or reduce injuries in any accident and many wearable devices are developed for this requirement. However, wearable systems have some limitations for user. Kinect sensor is a powerful tool which can provide skeleton data in the specified space 30 frames per second and each frame contains 25 joints of depth data on the whole body. Due to camera space restriction, some terminal joints are inferred or not tracked. Only the primary joints are adopted in this research to avoid the impractical events. Eliminate the jitter of the valuable depth data by applying an extended filter and classify the data to specific status classes depend on unique feature of human body actions. Experimental results show a sequence of activities from test subjects can be recognized as corresponding status in real time.

Interaction Between GIRK1 and GIRK4 Channel Subunits

Mentor(s): Radmila Sarac

Graduate

Oral Presentation

G protein-gated inwardly rectifying potassium (GIRK) channels belong to a large family of inwardly rectifying channels, and are responsible for regulating the heart rate and modulating neuronal excitability of certain neurons. They are activated by G protein coupled receptors (GPCRs), which release Gβγ from the inactive G protein complex Gαβγ upon binding of neurotransmitters like acetylcholine. GIRK channels assemble as tetramers either as homo or heteromeric structures comprising of four subunits - GIRK1, GIRK2, GIRK3 and GIRK4. The N- and C- termini lie in the intracellular region, which results in significant interactions between the cytoplasmic regions of the channel. This research focuses on understanding the structural and functional properties of GIRK channels. Specifically, the interaction between the wild type GIRK4 N-terminus with GIRK1 N-terminus-linker-C-terminus domains are analyzed by utilizing multiple experimental methods to evaluate protein expression, localization and channel function. We hypothesize that specific amino acid residues residing in the hydrophobic pockets formed between the GIRK subunits play an important role in domain association and channel activation. The Gβγ interaction with the intracellular domains of the channel subunits is also analyzed. Understanding how the interaction between different subunits influences domain association and channel activity is critical in elucidating some of the cellular mechanisms involved in the physiology of heart and the nervous system.

Reduction of Salmonella on Eggshells by Application of Bacteriophages

Mentor(s): Evert Ting

Graduate

Oral Presentation

Introduction: Bacteriophages have been documented as a promising tool in controlling food contamination. They have been shown to reduce bacterial populations on many foods. Phages also do not change organoleptic properties of foods and are completely harmless to humans. However, phage treatment of eggs remains to be extensively studied. The purpose of the study is to test the ability of bacteriophages to reduce eggs artificially contaminated with salmonella.

Methods: Bacteriophages that cause lysis of Salmonella were isolated from raw sewage samples collected from four local water treatment plants. Three isolates, 2J, 8P and 3Q were tested. Treatments were setup by inoculating Salmonella on eggshells and then treating shells with phage suspension at a ratio of 1:1000 at 22°C.

Results: Treatment of eggshells with phage 2J, 3Q, or 8P resulted in a 1.4, 1.2 and less than 1 respectively. Further studies showed that increasing treatment times from 5 min to 1 hour did not significantly increase Salmonella reduction. The addition of cations and anions did not significantly increase Salmonella reduction.

Significance: This study showed that phages 2J and 3Q can significantly reduce Salmonella on eggshells within 5 min at 22°C. Phage 8P was shown not to significantly reduce Salmonella with less than 1 log reduction.