Computer Engineering Commons^™

Scalable Distributed Communication Architectures To Support Advanced Metering Infrastructure In Smart Grid, Jian Zhou, Rose Qingyang Hu, Yi Qian

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we investigate the scalability of three communication architectures for advanced metering infrastructure (AMI) in smart grid. AMI in smart grid is a typical cyber-physical system (CPS) example, in which large amount of data from hundreds of thousands of smart meters are collected and processed through an AMI communication infrastructure. Scalability is one of the most important issues for the AMI deployment in smart grid. In this study, we introduce a new performance metric, accumulated bandwidth distance product (ABDP), to represent the total communication resource usages. For each distributed communication architecture, we formulate an optimization problem and obtain …

Distributed And Centralized Iterative Detection Of Self-Encoded Spread Spectrum In Multi-Channel Communication, Liang Chi, Won Mee Jang, Lim Nguyen

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

We propose self-encoded spread spectrum with two different iterative detection methods in multi-channel communication. The centralized iterative detection outperforms the iterative detection distributed over multiple channels. The results show that self-encoded spread spectrum with the centralized iterative detection is an excellent candidate for cognitive radio network.

Assurance Of Energy Efficiency And Data Security For Ecg Transmission In Basns, Tao Ma, Pradhumna Shrestha, Michael Hempel, Dongming Peng, Hamid Sharif, Hsiao-Hwa Chen

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

With the technological advancement in body area sensor networks (BASNs), low cost high quality electrocardiographic (ECG) diagnosis systems have become important equipment for healthcare service providers. However, energy consumption and data security with ECG systems in BASNs are still two major challenges to tackle. In this study, we investigate the properties of compressed ECG data for energy saving as an effort to devise a selective encryption mechanism and a two-rate unequal error protection (UEP) scheme. The proposed selective encryption mechanism provides a simple and yet effective security solution for an ECG sensor-based communication platform, where only one percent of data …

Dynamic Reconfigurable Multi-Cell Battery: A Novel Approach To Improve Battery Performance, Song Ci, Jiucai Zhang, Hamid Sharif, Mahmoud Alahmad

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Many electronic systems such as robotics, battery powered electric vehicles, and mobile computing devices are powered by multi-cell battery with limited energy capacity. Therefore, maximizing the battery performance such as operating time, available capacity, and lifetime is one of the major battery design challenges. Traditional approaches such as dynamic power management to maximize the battery discharge performance have treated multi-cell battery as a pure passive component with a fixed configuration. Thus, the multi-cell battery performance is determined by the weakest battery cell, leading to a low utilization of battery energy. In this paper, we propose a novel multi-cell battery design …

Impact Of Wireless Communication Delay On Load Sharing Among Distributed Generation Systems Through Smart Microgrids, Song Ci, Junjie Qian, Dalei Wu, Ali Keyhani

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Load sharing among distributed generation systems (DGS) is one of the most important topics in wireless-enabled smart microgrids, where a set of power inverters at different geographical locations work coordinately and collaboratively through wireless networks to meet the load requirement. Parallel power inverters operated in distributed generation systems rely on the underlying wireless communication channels to exchange power information among them for load sharing control. However, existing work in the area of load sharing has largely ignored the effect of wireless communication delay. Study has shown that the time-varying wireless communication delay may have a significant impact on the performance …

An Adaptive Algorithm For Corrupted Images, Deborah D. Duran-Herrmann, Qilin Qi, Yaoqing Lamar Yang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Noise is ever-present in communication channels and can produce devastating degradation to the images at the receiver end. In this paper, a novel approach to detecting different types of noise models in corrupted images is presented. Basically, it is a two-step process that has the ability to handle real-time applications due to its computational simplicity. The proposed algorithm handles error correction more efficiently in the second stage of processing, given a means to detect the type of noise present in the first stage. This algorithm will be verified and tested against existing methods on different noise models. Preliminary results show …

Lte Phy Performance Analysis Under 3gpp Standards Parameters, Fahimeh Rezaei, Michael Hempel, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Long Term Evolution (LTE) has been introduced by 3GPP (3rd Generation Partnership Project) and is poised to dominate the 4th generation (4G) of mobile telecommunication networks. In this article, we present an in-depth analysis of the LTE physical layer’s characteristics and its performance. Our work is unique in providing a detailed performance study based on Release 8 of the 3GPP standard. Several works have discussed the LTE performance; however, most have been restricted to limited scenarios. Our work shows a more comprehensive investigation of the maximum data throughput under different conditions and scenarios. Our performance study includes TDD and FDD …

Quantitative Performance Analysis Of 3.65 Ghz Mobile Wimax, Pradhumna Shrestha, Michael Hempel, Puttipong Mahasukhon, Tao Ma, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

3.65 GHz Mobile WiMAX spectrum is often a better commercial solution due to its attractive licensing requirements, in spite of the slightly lower coverage area. However, no significant performance data has been reported for 3.65 GHz equipment behavior. In this paper, we have presented an in depth analysis of a 3.65 GHz Mobile WiMAX solution. Our reported data can also contribute in performing link budget analyses and benchmarking similar equipment.

Performance Analysis For Direction Of Arrival Estimating Algorithms, Pradhumna Shrestha, Michael Hempel, Puttipong Mahasukhon, Tao Ma, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Smart antennas have emerged as one of the most promising directions in supporting maximum communication link throughput. In this paper, we have investigated the impact of smart antennas on a complex mobile network such as a railroad wireless communications system. The objective is to analyze the selection of a Direction-Of-Arrival (DOA) estimation algorithm which provides the maximum efficiency when deployed in our railroad testbeds for wireless vehicular communication. Our findings are discussed to provide an indepth understanding of how different algorithms should be selected to support efficient network operations.

Cross-Layer Optimized Coding Mode Selection For Wireless Video Communications, Yun Ye, Song Ci, Dalei Wu

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

This paper proposed a coding mode selection method for video transmission over wireless networks. Unlike previous mode selection methods disregarding channel distortion or assuming constant packet loss rate (PLR), this method includes a cross-layer controller to collect both source and channel information. The mode selection process is formulated as a delay constrained distortion minimization problem. The three components in the resulting Lagrange cost function, namely distortion, Lagrange multiplier and packet delay, are estimated with online channel information feedback. Suboptimal coding decision and physical layer modulation and coding scheme (MCS) are determined by the controller for each packet. In our experiment, …

A General Attack Method For Steganography Removal Using Pseudo-Cfa Re-Interpolation, Pradhumna Shrestha, Michael Hempel, Tao Ma, Dongming Peng, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Watermarking and steganography are two of the most researched topics in multimedia forensics. However, easy availability of tools and technology has made their misuse a serious concern. To counteract this development some effective tools are necessary to remove malicious steganography. In this work, we introduce a novel watermark attack method which can destroy hidden information embedded in images based on the principle of re-interpolation of Color Filter Array (CFA) artifacts. In digital cameras and scanners, CFA filters are used to acquire low-resolution physical color channel information and produce a high-quality image by subsequent interpolation. We propose to emulate a similar …

A Cross-Layer Design For The Performance Improvement Of Real-Time Video Transmission Of Secondary Users Over Cognitive Radio Networks, Haiyan Luo, Song Ci, Dalei Wu

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Cognitive radio (CR) has been proposed as a promising solution to improve connectivity, self-adaptability, and efficiency of spectrum usage. When used in video applications, user-perceived video quality experienced by secondary users is a very important performance metric to evaluate the effectiveness of CR technologies. However, most of the current research only considers spectrum utilization and effectiveness at medium access control (MAC) and physical layers, ignoring the system performance of the upper layers. Therefore, in this paper, we aim to improve the user experience of secondary users for wireless video services over CR networks. We propose a quality-driven cross-layer optimized system …

Quantifying Performance Of Cooperative Diversity Using The Sampling Property Of A Delta Function, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we present a simple approach to evaluating the performance of amplify-and-forward cooperative diversity. The �-function can be asymptotically reduced to a delta (impulse) function. We extend the result to cooperative networks in fading channels. The proposed approach introduces a simple technique to evaluate the performance of complex networks by sampling.

Quantifying Performance In Fading Channels Using The Sampling Property Of A Delta Function, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

We apply the sampling property of a delta function to obtain the probability of error in fading channels. Our approach reduces the integration to a sampling. The sampling point is obtained in terms of fading parameters and the average signal-to-noise ratio (SNR) to provide the closed form solution of the performance.

A Simple Upper Bound Of The Gaussian �-Function With Closed-Form Error Bound, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

We present a simple upper bound of the Gaussian Q-function with its closed-form error bound. The proposed approximation can be applied to the evaluation of the average error probability of digital modulations with its error bound. Our bit error rate (BER) bound can be easily applied to fading channels.

Power Controlled Multirate Multimedia Transmission In Self-Encoded Spread Spectrum Over Dynamic Fading Channels, Liang Chi, Poomathi Duraisamy, Won Mee Jang, Lim Nguyen

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we propose to apply power control to self-encoded spread spectrum (SESS) in multirate and multimedia applications. The transmitter employs power control to to combat dynamic channel fading and the receiver employs decorrelation to reduce interference from multiple applications. We show that iterative detection can significantly improve the system performance. The proposed approach also improves the power efficiency which is essential in battery-driven communications such as mobile cellular systems.

Self-Encoded Spread Spectrum For Multirate Multimedia Communication In Multipath Channel, Liang Chi, Won Mee Jang, Lim Nguyen

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we propose the self-encoded spread spectrum (SESS) with multirate multimedia communication in multipath channel. In multirate multimedia SESS system, each application has their own transmission bit rate. The signal is transmitted through multipath channels each with different channel gain and time delay. We view the main path as the signal resource and other paths as interference. At the receiver side, decorrelation scheme is employed for the main path combined signal not only to reduce the crosstalk between different applications, but also to provide a better estimation for the despreading sequence in the main path. Interference cancellation(IC) in …

Low-Complexity Image Coder/Decoder With An Approaching-Entropy Quad-Tree Search Code For Embedded Computing Platforms, Tao Ma, Pradhumna Shrestha, Michael Hempel, Dongming Peng, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we propose a fast, simple and efficient image codec applicable for embedded processing systems. Among the existing image coding methods, wavelet quad-tree is a foundation leading to an efficient structure to encode images. By searching significant coefficients along quad-trees, an embedded efficient code can be obtained. In this work, we exploit hierarchical relations of the quad-tree structure in terms of searching entropy and present a quad-tree searching model that is very close to the searching entropy. By applying this model, our codec surpasses SPIHT [1] by 0.2-0.4 db over wide code rates, and its performance is comparable …

Distributed Mimo Technologies In Cooperative Wireless Networks, Shichuan Ma, Yaoqing (Lamar) Yang, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Multiple-input multiple-output techniques enhance wireless communications performance by taking advantage of spatial diversity. However, most traditional MIMO systems hardly achieve large spatial diversity because of limited terminal size. In this article, we present recent advances of the distributed MIMO technologies in cooperative wireless networks. We also compare and discuss various relay protocols and cooperative strategies. Our simulation results indicate that distributed MIMO systems can provide larger spatial diversity, and the data rate in cooperative networks can be significantly increased.

Impact Of Interference On Secrecy Capacity In A Cognitive Radio Network, Zhihui Shu, Yaoqing Lamar Yang, Yi Qian, Rose Qingyang Hu

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we investigate secrecy capacity of a cognitive radio network based on stochastic geometry distributions. We consider the Poisson process of both the secondary users and the eavesdroppers, and analyze how the stochastic interference from the secondary users can influence the secrecy capacity of the primary users. First, we describe a network model with primary users, secondary users and eavesdroppers in a cognitive radio communication network environment, and derive the expression of secrecy capacity in an additive white Gaussian noise channel. Then, we study the outage probability of secrecy capacity of a primary node from a secure communication …

Battery Capacity Footprinting And Optimization Analysis For Wireless Multimedia Communication, Jianxin Sun, Dalei Wu, Song Ci

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Micro-electronic industry has been boosting the capability of wireless mobile devices on full-scale. However, battery, as the only power source of most mobile devices, is experiencing a relatively slow development. Therefore, how to optimally utilize the limited battery energy on mobile devices under a predefined performance requirement becomes a critical issue. On the other hand, it is still unclear that how the battery capacity consumption is allocated on different working pattern of a specific video codec under various tempo-spatial scales and parameters, which has posed a design challenge on power management on multimedia communication system. Furthermore, an optimization method is …

Video Surveillance Over Wireless Sensor And Actuator Networks Using Active Cameras, Dalei Wu, Song Ci, Haiyan Luo, Yun Ye, Haohong Wang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Although there has been much work focused on the camera control issue on keeping tracking a target of interest, few has been done on jointly considering the video coding, video transmission, and camera control for effective and efficient video surveillance over wireless sensor and actuator networks (WSAN). In this work, we propose a framework for real-time video surveillance with pan-tilt cameras where the video coding and transmission as well as the automated camera control are jointly optimized by taking into account the surveillance video quality requirement and the resource constraint of WSANs. The main contributions of this work are: i) …

A Secure Data Aggregation And Dispatch Scheme For Home Area Networks In Smart Grid, Yun Ye, Yi Qian, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Cyber security for smart grid communication systems is one of the most critical requirements need to be assured before smart grid can be operationally ready for the market. Privacy is one of a very important security services. The customer information privacy in smart grid need to be protected. Smart grid data privacy encompasses confidentiality and anonymity of the information extracted from smart devices and metering transmission in a smart grid communication system. In this paper, we consider a home area network as a basic reading data aggregation and dispatch unit in smart grid systems, and we propose a secure in-network …

A Secure And Reliable In-Network Collaborative Communication Scheme For Advanced Metering Infrastructure In Smart Grid, Yun Ye, Yi Qian, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

We consider various security vulnerabilities of deploying Advanced Metering Infrastructure (AMI) in smart grid, and explore the issues related to confidentiality for customer privacy and customer behavior as well as message authentication for meter reading and control messages. There are only a very few research work on AMI authentications, and no work exists on confidentiality for user privacy and user behavior, from the best of our knowledge. In this paper, we propose an in-network collaborative scheme to provide secure and reliable AMI communications in smart grid, with smart meters interconnected through a multihop wireless network. In this approach, an AMI …

A Novel Adaptive Distributed Cooperative Relaying Mac Protocol For Vehicular Networks, Ting Zhou, Hamid Sharif, Michael Hempel, Puttipong Mahasukhon, Wei Wang, Tao Ma

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Explosive growth in Information Technology has enabled many innovative application areas such as large-scale outdoor vehicular networks for vehicle-to-vehicle communications. By providing time-sensitive and location-aware information, vehicular networks can contribute to a safer and more efficient driving experience. However, the performance of vehicular networks requires robust and real-time data communications and is impacted by high mobility, intermittent connectivity, and unreliability of the wireless channel. In this paper, a novel adaptive distributed cooperative medium access control (ADCMAC) protocol is proposed in order to address the inherent problems in the IEEE 802.11 standard when employed in vehicular networks. ADC-MAC exploits spatial diversities …

A Cross-Layer Parallel Handover Optimization Scheme For Wimax Networks, Ting Zhou, Hamid Sharif, Michael Hempel, Puttipong Mahasukhon, Tao Ma, Pradhumna Shrestha

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

The handover performance plays a crucial role in guaranteeing the quality of real-time applications in WiMAX networks. In general, a handover process can be divided into four stages: i) cell reselection, ii) handover preparation, iii) link layer handover, and iv) IP layer handover. A cross-layer parallel handover optimization (CPHO) scheme is proposed in this paper to reduce the handover signaling overhead and latency in each stage. The key idea of our proposed scheme is that uses the knowledge achieved from the backhaul inter-BS communications to reduce the HO control message load in wireless links and overlaps the executions of the …

A Novel Channel Probing/Scanning Scheme For Secure Fast Handoff In Ieee 802.11-Based Wireless Networks, Ye Yan, Yi Qian, Rose Qingyang Hu

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

With the proliferation of wireless networks for practical deployments in recent years, secure fast handoff has become significantly important to provide secured access while reduce the latency caused by handoff procedure. Channel probing/scanning delay has been a major contribution to the overall latency of handoff in IEEE 802.11 based wireless networks. In this paper, we present a novel secure fast handoff scheme that adopts network-assisted radio statement (NACS) to eliminate lengthy probing/scanning delay by taking advantage of the knowledge of network topology of neighboring nodes in the network. We apply an opportunistic mechanism to retrieve the channel condition from neighboring …

Quantitative Analysis Of Propagation Characteristics For Mobile Wimax, Pradhumna Shrestha, Puttipong Mahasukhon, Michael Hempel, Tao Ma, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In wireless networks, careful planning and link budget analysis is required for delivering maximum throughput reliably with minimum overhead. The efficiency of planning and eventual network performance is totally dependent upon the accuracy and quality of data used for analysis. In most studies, computer simulations and analytical models are used for generating such data. However these simulations are limited to many assumptions which are different from the actual implemented hardware, therefore, the data generated are not accurate. In this paper, we analyze the performance of Mobile WiMAX utilizing the empirical data measured from leading WiMAX equipment. We believe this data …

Dynamic Video Object Detection With Single Ptu Camera, Yun Ye, Song Ci, Yanwei Liu, Hui Tang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

This paper presents a video object detection method under dynamic background with single PTU (pantilt unit) camera. The overall procedure contains two steps. First the moving object is tracked through interactive Mean Shift estimation and PTU control. Camera angular speed is updated online according to the estimated object position, whereby the object can remain in the center area of the image plane. In the second step, the foreground is detected through background subtraction and shape contour. An adaptive correlation thresholding method is applied to mitigate the detection distortion in boundary areas. Variational level set contour is then applied to further …

Power Controlled Coded-Sequence Self-Encoded Spread Spectrum Communications, Poomathi Duraisamy, Liang Chi, Won Mee Jang, Lim Nguyen

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we propose to apply power control to coded-sequence self-encoded spread spectrum (CS-SESS) communications in dynamic fading channels. We determine the statistical characteristics of the power enhancement in the transmitter due to power control and show that the proposed approach improves the power efficiency in mobile cellular systems.

In addition, we propose to mitigate self interference in CSSESS by exploiting the information that the transmitter obtains, through feedback training sequences, about the de-spreading code in the receiver. The results show that the mitigation is significant even with only selective training chips from the de-spreading sequence. Similar improvement can …