Performance Improvement of V2X Communications
Vehicle-to-everything (V2X) communications have been taking a critical role in facilitating safety applications in intelligent transportation systems (ITS). However, both of the two representative technologies–Dedicated Short-Range Communications (DSRC) and cellular V2X (C-V2X)–have been showing limitations: (i) contention for bandwidth and (ii) latency. Such limitations are expected to cause breakdown of V2X communications in scenarios such as very high traffic density, which this project refers to as “safety hole.”
This research (i) investigates the fundamental performance of a V2X network and (ii) designs a protocol to enhance the communications performance.
Impacts of Mobility on Performance of Blockchain in V2X Networks
This research investigates how 'mobility' affects the performance of a blockchain system operating in a vehicle-to-everything (V2X) network. The mobility of nodes incurs a unique challenge to a blockchain system due to continuous change and dynamicity in connectivity of the nodes. Specifically, the mobility makes a proof-of-work (PoW) process difficult since, while moving, the nodes can only have a limited length of time for a "rendezvous" to exchange a new block for verification. For this reason, an accurate modeling for the block exchange behavior in a V2X network is also challenging, which nevertheless has not been discussed in previous studies. Therefore, this present work provides an analysis framework that formulates the impact of mobility on a blockchain system's performance in a V2X network based on three key metrics: (i) the probability of a successful addition of block to the chain, (ii) the stability of a rendezvous, and (iii) the number of blocks exchanged during a rendezvous.
Human EMF Exposure in Wearable Communications Systems
Rapid advancements in chip design, computing, sensing, and communications technologies have led to the unprecedented growth of wearable devices. Wearables provide easier access to information and convenience for their users. They present a myriad of applications from low-end health and fitness trackers to high-end gears for virtual reality or augmented reality.
The potential of millimeter wave (mmW) frequencies for wearable communications is enormous for applications requiring Gbps throughput. Such networks might use wireless standards including 5G or IEEE 802.11ad/ay, based on which commercial products are already available.
A major concern regarding wearable communications in mmW is human biological safety under radio-frequency (RF) exposure, mainly due to extremely short distances from a transmitter to the human skin. The human body absorbs electromagnetic field (EMF), which causes thermal or non-thermal heat in the affected tissues. Current guidelines on RF exposure normally apply specific absorption rate (SAR) as the metric for frequencies below 6 GHz. For mmW, since the primary energy remains in the surface layer of the skin, power density (PD) instead of SAR is used for the guidelines. However, PD cannot adequately evaluate the effect of human health impacts—e.g., temperature elevation of a direct contact area. Moreover, some tissues—e.g., eyes—are more vulnerable to EMF-induced heating and thus require more attention. It is necessary to continually update regulations based on new materials, frequencies, device types, and transmitted powers.
To this end, this research performs mathematical analysis of human RF exposure in wearable communications operating in the mmW spectrum.
Our endeavor in the near future will be focused on mitigation of RF exposure in mmW wearable communications. A larger number of transmitters in a network enables a wider diversity in selection of an alternative routing path achieving a sufficiently high data rate but at a low enough SAR. Note that a wearable device presents a very short range of communications, attributed to a low transmit power. It will make difficult to obtain enough diversity in alternative transmitters, which may in turn make difficult to mitigate the SAR by switching to an alternative transmitter in a network.
This research is expected to afford the opportunity for Electrical and Computer Engineering (ECE) students to develop expertise in their chosen fields as well as gain experience working in a compelling context across inter-disciplinary lines—viz., biology.
Millennium Corporation, Real-time data analysis to achieve risk reduction and enhanced security monitoring, ($84,557, Jul. 2019 - Jun. 2020, PI)
Georgia Southern University Faculty Development Committee Award, Wireless communications in nanonetwork for healthcare applications, ($9,986, Jul. 2019 - Jun. 2020, PI)
Georgia Southern University College of Engineering and Computing Faculty Research Seed Grant, Low-cost improvement of wireless sensor network for surface water management, ($7,000, Jan. - May 2019, PI)
Georgia Southern University College of Engineering and Computing Faculty Research Seed Grant, Promotion of traffic safety and communication efficacy in connected vehicles, ($8,000, Jan. - May 2019, Co-PI)
Georgia Southern University College of Engineering and Computing Undergraduate Research Award, Security in underwater communications, ($1,684, Jan. - May 2019, Faculty Advisor for Mr. Treston Montoya)
Georgia Southern University Faculty Development Summer Award, Creation of hands-on projects on disaster emergency communications ($3,000, Jun. - Jul. 2018, PI)
Georgia Southern University College of Engineering and Computing Faculty Research Seed Grant, Operation of future cellular communications in shared bands ($8,000, Jan. - May 2018, PI)