UC Berkeley Ph.D.

Statement of Purpose

2009 was the year that marked a transition in my life: on a personal level, I had just completed my military service, but more importantly, it was the year when the first 3GS IPhone was officially released in the Korean market, opening an unprecedented horizon: going beyond the physical geographical boundaries to be connected online, stimulated my academic curiosity in wireless networks – interested in not only the convenience but more importantly, the fundamental nature of wireless networks, especially in the realm of ad-hoc network, enabling direct data-transmission among devices without having to bypass the inconvenience of communication via base-stations allowing transmission of data in previously conceived ‘disconnected areas,’ with tremendous application possibilities in various fields including VANET (Vehicular Ad-hoc Network), Wireless Sensor Network, and military communications. In particular, application of these ad-hoc networks to the vehicular industry gave rise to unprecedented revolutionary changes. Therefore, in line with these developments, I too began directing my interest in ad-hoc networks and VANET pertaining to automobiles.

Therefore, in college in not only extended my studies on communication and networks, but also dedicated tremendous time to programing language (C, C++, CUDA, Verilog and etc.) which I believed was quintessential to my contribution to robotics. Furthermore, enrollment into courses like Communication Theory, Probability and Random Variables, and Digital Communication helped me to become versed in modulation, queueing theory, and channel coding while through Computer Networks courses I acquired knowledge on fundamental network structures like OSI layers. Therefore, while I had successfully manifested my general understanding on communication and network, I wanted to manifest greater understanding on these topics on a graduate level. In particular, I found the topic of ad-hoc network to be of particular interest. While I was contemplating on these ideas, I participated in the Development and Optimization of MANET (Mobile Ad-hoc Network) using Military Radio Communication” with Samsung Thales Corporation in the field of ad-hoc networks.

Furthermore, as this project pertained to military radio network, it was imperative to guarantee minimum transmission rate under any geographical and physical conditions, and as starvation phenomenon occurs according to the topology of the node on ad-hoc networks capable of multi-hop, the transmission rate for certain nodes could become low. Therefore, in order to overcome these limitations, I first identified the minimum overhead through the cross layer design for the condition of out device transmission through the distribution method, helping to elevate the functionality. By providing information through collaborative function of devices in resolving the many problems associated with wireless networks through this project, I manifested my interest in algorithm modeling and encompassing simulations, which became the topic of my Ph.D. studies.

First, I believe the following elements are imperative in proposing system design and algorithms for research on ad-hoc networks: First, the distributed structure and algorithm; second, maximizing the performance based on cooperation between devices within the network; and third, consideration of multi-hop. In fact, in 2013, Professor Laufer and Kleinrock through “On the capacity of CSMA/CA Multi-hop networks” analyzed the capacity region of multi-hop networks using CSMA/CA MAC protocol, where I am currently researching on various methods to satisfy QoS (Quality-of-Service) and User Experience through cooperation and distribution of various devices. Therefore, utilization of my knowledge on ad hoc networks, I would like to design protocols to enhance the performance on VANET (Vehicular Ad hoc Network). While recent works on vehicular technologies have focused on scalability, security approaches, and single-hop broadcast, there is growing need to explore the subjects of satisfying QoS using multi-hop broadcast or cooperation among vehicles and distributed MAC protocol.

Furthermore, mathematical modeling, analysis and design must first be executed for research on multi-hop considered VANET and IVC, considering the unique characteristics of the region and the vehicle. And, selection of nodes (transmission-mediation-receipt) is critical in multi-hop consideration, where introduction of limited number of relay nodes on fast moving vehicles guarantee expansive delivery, the time for secured and stable wireless communication is relatively shortened, while for slow moving cars, the opposite phenomenon would be detected. Furthermore, as the speed and density of the vehicle differs according to various environmental conditions, I hope to propose optimize algorithms based on cross-layer design to effectuate network efficiency using the cooperative IVC methodology, through comprehensive mathematical modeling and algorithm analysis which would be verified through post-simulation experiments.

To this end, the research opportunities through the Ph.D. program at UC Berkeley provide the optimum environment in successfully completing my proposed studies. In addition to the many course offering, helping me to reinforce necessary theoretical knowledge on ad hoc network and vehicular technologies like VANET and IVC, I am most excited collaborate and participate in various research activities at the Communications Research Center at the U.C. Berkeley Wireless Foundation, reflective of my current academic interests: we need to better understand a network viewpoint wherein nodes can cooperate intelligently taking advantage of the special properties inherent in wireless communication and we need to develop highly distributed architectures and algorithms. Also, highlighting intellectual cooperation between nodes to serve network functions is on the same page as my academic direction. Once I have completed my proposed studies, I would like to apply the mathematical formulas and program based simulations to real life devices through collaborative efforts with the industries as lab based experiments would have new challenges in its actualization in the real world. Then, if possible, I would like to develop new technologies in the field of communication network as to maximize efficiency and sustainability in this ever changing wireless communication industry. I believe implementing and devising new ideas in the real world would help me to contribute my knowledge to the creation of a more efficient communication network of tomorrow. Furthermore, I am excited to apply my knowledge and expertise on VANET technology in the vehicular industry, participating in concerned communication protocols and standardization projects, contributing to the development of ad-hoc networks in the future vehicular industry and beyond.