CCL Winter Camp 2014

Daikura Ski Resort, Minami Aizu, Fukushima

Mar. 5-6, 2014

Venue & Time

Day one: Skiing Activities

Day two: Workshop Program

Opening

By Prof. Anh T. Pham

Approximation sum of random variables and its application in wireless communications

By Pham Van Thanh

Abstract: Relay and diversity techniques have been attracted much attention in wireless communications. In such kind of systems, received signal at the destination normally is the summation of transmitted signals on each sub-channel. For each kind of wireless networks, the sub-channel is characterized by a specific random distribution. Therefore, study on the sum of random variables is necessary to investigate the performance of overall system. In my presentation, we will introduce some approximation methods for sum of random variables and its applications in wireless communications.

Client-based Advertisement Insertion for Adaptive Video Streaming

By Le Thai Hung

Abstract: Advertisement is a crucial factor in business models of Internet video streaming. So far, most methods for advertisement insertion are implemented at a provider or a proxy inside the networks. In this paper, we present an approach for client-based advertisement insertion in HTTP streaming, which has become a new trend in multimedia delivery nowadays. The advantages of our approach include 1) client’s unawareness of advertisement media, 2) flexibility in inserting and personalizing advertisements, and 3) smooth transition between content and advertisement.

Background subtraction and its application

By Vo Tuan Dung

Abtract: Background subtraction aims to isolate objects from the rest of the image which isn’t of interest; the reason for doing this should be obvious. For example, in video security, the camera mostly has no interest in boring background, which doesn’t change by time. What is of interest is when people or vehicles enter the scene and we want to segment those events from background. In addition, background subtraction also serves for separating parts of objects such as face, hands... from one person. In this work, I will study several background subtraction models and implement these methods in the context of hand segmentation.

High efficiency MIMO VLC with spatial multiplexing gain

By Tran Ngoc Anh

Abstract: It is expected that LED lighting will be widely employed in lighting technology due to environmental and commercial advantages. Additionally, LEDs can also be used as a transmitter for data transmission this technology is referred to as Visible light communications (VLC). Especially, in typical indoor scenarios, e.g. office or home, VLC is expected as a strong contender to WiFi for home networking and a reliable successor in case of the use of WiFi is concerned. However, VLC have to overcome several challenges including limited bandwidth and applicable modulation schemes. Utilizing multiple input multiple output (MIMO) system is one promising approach to achieve high data rate connection. Two well-known MIMO techniques Spatial multiplexing (SMP) and Spatial modulation (SM) that offer the multiplexing gain becomes attractive research topic in several recent years. In my research, I will apply SM and SMP into an indoor VLC system in diffused environment. The system performance will be compared to realizing the benefit of two schemes over classical MIMO techniques Repetition code (RC).

Design and Performance Evaluation of VLC Indoor Positioning System using Optical Orthogonal Codes

By Sari Yamaguchi

Abstract: Indoor positioning system has become popular in recent years. Visible light communication identification is a system that gets positioning information from LED lights. It is expected to use indoor environment, where GPS is unavailable. Our proposal is to design the VLC based indoor positioning system by using Optical Orthogonal Codes (OOC). The simulation room is considered the big area like major stations and airports. Finally, we evaluate that performance.

An evaluation of bitrate adaptation methods for HTTP Live Streaming

By Nguyen Van Duc

Abstract: In recent years, HTTP streaming has been quick adopted by major vendors and providers. Along with that, many adaptation methods have been proposed. We will provide an evaluation of such methods in context of live video streaming. The evaluation is carried out not only in terms of bitrate and buffer behaviors but also in terms of the perceptual impact to end users.

Selective Relay Decode-and-Forward QAM/FSO Systems Over Atmospheric Turbulence Channels

By Vu Trong Bach

Abstract: In this paper, we analytically investigate the performance of selective relay FSO systems employing DF scheme and QAM taking into account of the fading effect caused by the atmospheric turbulence. The lognormal distribution is used to model the fading channel. The closed-form of system symbol-error rate (SER) is analytically derived, and the numerical results quantitatively highlight the impact of the number of relays, turbulence strengths and QAM signaling on the average SER improvement of the selective relay FSO systems. We also verify the theoretical analysis by Monte-Carlo simulation and a good agreement between the analytical and simulation results is confirmed.

Cross-Layer Design and Analysis for FSO Links using Automatic Repeat Request and Adaptive Modulation/Coding Schemes

By Vuong Viet Mai

Abstract: This presentation introduces a framework for cross-layer management of data transmissions in free-space optical (FSO) systems over atmospheric turbulence channels, in which link layer automatic repeat request (ARQ) and physical layer adaptive modulation and coding (AMC) are integrated to improve the system’s spectral efficiency. The system performance is analytically studied in terms of average frame-error rate and average spectral efficiency, for which we derive closed-form expressions. In numerical results, we show how the proposed scheme significantly outperforms a conventional one, and discuss cross-layer designs for parameters’ selection in both physical layer and link layer to optimise the system performance over different atmospheric turbulence conditions.

Bandwidth sharing for multiple streaming clients in home networks

By Bui Duy Huong

Abstract: A few years ago, we use a computer or IPTV for watching video at home. Nowadays, any smart devices can also download and display video from the Internet. So, a house's Internet access link should
support multiple devices and multiple connections simultaneously. The main problem is that these connections will compete with each other for bandwidth, making the players unstable. My research focus is to solve this problem. In this talk, I will present a shaping method that can significantly reduce the oscillation of andwidth (restrict competition between the players) and thus improve the QoS for
all clients.

Receive Diversity in Multihop Free-space Optical Communications

By Luong Anh Duy

Abstract: In this paper, we propose the use of spatial receive diversity in multihop terrestrial free-space optical
communications as an effective solution to enhance the system reliability. The system performance in
terms of outage probability is derived in closed-form for both amplify-and-forward and decode-and-
forward relaying. The negative effect of channel correlation on the system performance is
comprehensively examined. Based on that, we quantitatively discuss various issues regarding the practical
design of the system.

Simulation and performance theoretical analysis of OOK optical communication system using APD receiver

By Abdoulaye Niang

Abstract: For this project, using OOK optical communication model to simulate analysis the performance of the optical signal when an APD receiver is used. It was seem that the performance of such systems is affected by BER rate, however using APD receiver could improve the performance and optimised it by an appropriate selection of APD average gain.

Optical Amplify-and-Forward Multihop WDM/FSO for All-Optical Access Networks

By Trinh Viet Phuc

Abstract: Multihop free space optical (FSO) system using optical amplify-and-forward (OAF) relaying technique combined with wavelength division multiplexing (WDM) is proposed for all-optical access networks. The proposed system can provide a low cost, flexible and high-bandwidth access network for multiple users. To investigate the system performance, we consider a special case of dual-hop WDM-FSO system taking into account the effects of all noises, interchannel crosstalks, as well as path loss and geometric spreading of optical beam over atmospheric turbulence channels. In addition, pulse position modulation (PPM) is employed for improving the overall performance. Our results show that OAF technique combined with PPM scheme can be a good solution for mitigating the effect of atmospheric turbulence. Moreover, the required amplifier gain corresponding to a specific value of BER, transmission distance, and turbulence strength is also quantitatively discussed.

Closing + photo session: 12:00~12:15PM

12:30PM: Lunch at the Ski Resort