Networks

Research Projects/Thesis (Archives)

The following are the current research projects/thesis being undertaken at NRL.

Active Protocol Label Switching (APLS) and Resilience

Ph.D Candidate: William Lau
Description:
This project investigates new approaches to provide better support for services in the network. The objective is to design and develop a service-oriented network for the next generation of network applications. We have developed a prototype of our new label switching architecture called: Active Protocol Label Switching (APLS). The prototype is built into the Linux kernel and is the platform for further R&D in service-oriented networking. The current emphasis of our project is on provisioning network resilience that is suitable for APLS. We have taken the approach of online computation where service connections with resilience are setup on-demand without the need for complete knowledge of the traffic matrix. This better fits the dynamic environment of the next generation network applications. We proposed and evaluated several new restoration algorithms for both unicast and multicast that aims to minimize the backup bandwidth requirement.

 

Adaptive Resource Management in Mobile Wireless Cellular Networks

Ph.D Candidate: Md.Monir Hossain
Description:
Due to rapid advances of wireless devices, bandwidth, technology, and others, wireless communication is growing fast and will definitely continue to grow in the near future. Wireless communication is getting popularity day by day. Future wireless mobile cellular networks wil have full IP-based (i.e., packet switching technology) infrastructure in order to provide not only the voice service but also data, video, and other internet services. However, there are some inherent problems in wireless networks such as high bit error rate, fading, and scare bandwidth. Wireless resource is one of the precious things in this world. To provide enough quality of service for video and voice traffic, the wireless networks must have to provide enough resoruce/bandwidth for these traffics. Emerging mobile wireless networks are characterised by significant uncertainties in mobile user population and system resource state. Such networks require adaptive resource management that continuously monitor the system and dynamically adjust resource allocations for adherence to the desired system performance requirements. We propose adaptive resource management techniques that are based on feedback control theory. The controller dynamically solves resource allocation problem using classical control law. We study performance of proposed controller and derive optimum values for controller parameters using discrete event simulation.

 

A CDMA-Based, Self-Organizing, Location-Aware Media Access Control Protocol

Ph.D Candidate: Michael Liu
Description:
Continuing advances in Micro-Electro Mechanical Systems (MEMS) enables the construction of wide variety of sensors/actuators. These sensors/actuators consist one or more sensing units, embedded microprocessors and low power radios. Sensors are normally powered by batteries and communicate untethered in short distance. Large number of distributed sensors can organize themselves into a multi-hop wireless sensor networks. The potential broad range of applications of such sensor networks have garnered much academic and industrial attentions in recent years. With sensor network applications span a broad range of domains from wildlife tracking to real-time battlefield surveillance, we argue that no single MAC protocol is suitable for all sensor network applications. In this poject, we proposed a novel CDMA-based, self-organizing, location-aware MAC protocol for sensor networks. While previously proposed MAC protocols for sensor networks primarily prioritized energy-efficiency over latency, our protocol design balanced the energy-efficiency, latency, accuracy, and fault-tolerance of sensor networks. Although our research work is targeting sensor networks, we are expecting that our protocol can also be used in the future ubiquitous computing environment where traffic may be high and latency requirement is stringent.

 

Anchor Free Localization for Ad-hoc Wireless Sensor Networks

Ph.D Candidate: Muhammad Sarfraz Nawaz
Description:
This project deals with Localization algorithms for wireless sensor networks. Most of the work is related to anchor free network localization.

 

Bandwidth Broker

Ph.D Candidate: Jahan Hassan
Description:
In  this  Ph.D project,  we  propose  Cell-Hopping:  a new  model  for wireless communications. Cell-Hopping  represents an wireless multihop packet-switching network   where   there   are   basestations  contributed   by   small operators. This network consists of two-level hierarchy: at the bottom level there are mobile user terminals,  and at the top level there are basestations  creating  an infrastructure for  the  network. We also propose a framework for  cell-hopping location management called CDLM: Cell-Based    Distributed   Location   Management    in   Cell-Hopping Network.Performance Evaluation of CDLM is done by simulation studies.

 

Cell-Hopping: An Alternate Network Architecture for Next Generation Mobile Communications

Ph.D Candidate: Jahan Hassan
Description:
In  this  Ph.D project,  we  propose  Cell-Hopping:  a new  model  for wireless communications. Cell-Hopping  represents an wireless multihop packet-switching network   where   there   are   basestations  contributed   by   small operators. This network consists of two-level hierarchy: at the bottom level there are mobile user terminals,  and at the top level there are basestations  creating  an infrastructure for  the  network. We also propose a framework for  cell-hopping location management called CDLM: Cell-Based    Distributed   Location   Management    in   Cell-Hopping Network.Performance Evaluation of CDLM is done by simulation studies.

 

Coverage Issues in Wireless Sensor Networks

Ph.D Candidate: Nadeem Ahmed
Description:
A primary issue for any wireless sensor network deployment is to ensure that the target area is covered to the desired degree. We explore the coverage issues in wireless sensor networks by employing more realistic coverage models. The work is based on hybrid sensor networks, consisting of both static and mobile sensor nodes. Mobility of the nodes is utilized for coverage enhancement and maintenance.

 

Efficient Multicasting/Broadcasting in Multi-Radio Multi-Channel Multi-Rate Wireless Mesh Networks

Ph.D Candidate: Junaid Qadir
Description:
In a multi-rate wireless network, a node can dynamically adjust its link transmission rate by switching between different modulation schemes. For the current IEEE802.11a/b/g standards, this rate adjustment is limited to unicast traffic. In this project, we study the problem of efficient routing and packet distribution for multicast traffic flows in a multi-rate wireless mesh networks (WMN). We assume that the MAC layer of future WMNs will provide some form of multicast support, where the transmitter may be able to specify the transmission rate of the MAC-layer multicast, and, either explicitly or implicitly, the recipients of the multicast. Assuming such MAC layer multi-rate multicast capability, our goal is to study how low-latency (and possibly high throughput) network layer multicast of data traffic can be realized.

 

Efficient Resource Management Framework for Active Networks

Ph.D Candidate: Fariza Sabrina
Description:
Active network technology envisions deployment of virtual execution environment within network elements, such as switches and routers. As a result, inhomogeneous processing can be applied to network traffic. To use such technology safely and efficiently, individual nodes must provide mechanisms to enforce resource limits. This implies that each node must understand the varying resource requirements for specific network traffic. Development of  efficient resource allocation models for active nodes is a fundamental step toward large scale deployment of active networks.
This PhD research has focused on developing an efficient resource management  framework that can be successfully used in active and hybrid networks.

 

High-Performance Wireless TCP/IP for Inflight Internet Access

Ph.D Candidate: Adeel Baig
Description:
By some estimates, there are 20 million frequent business travelers worldwide. In today's world with the increased popularity in wireless communication and computing devices, aeronautical travelers will be able to access Internet in the aircraft. In this way they can check their emails, browse the web and can enjoy the full range of online entertainment/business facilities. Most of these applications require reliable date transfer. TCP is the most widely accepted protocol for reliability, connection orientation and full duplex communication in wired networks with stationary hosts. The fundamental problem with TCP over wireless networks is underestimation of bandwidth. Wireless links have low bandwidth and high link latencies. Thatês why any packet loss in wireless link is mistakenly taken by TCP as network congestion, which triggers the slow-start algorithm and causes under estimation of the available resources.The purpose of this research is to improve the performance of TCP by introducing some enhancements in the traditional TCP. So that it can perform well to provide reliable and  fast data transfer inside the high speed aircraft.

 

Multimedia Transmission over Wireless Network

Ph.D Candidate: Rui Zhao
Description:
To support multimedia service over wireless network, both the handset and network need to support multiple simultaneous calls from a single mobile station, including voice, circuit data, packet data, and video. However, todayês mobile networks were originally optimized for voice traffic. History and commercial reality dictate that in the future the mobile network will need to be provided across a wide range of radio frequencies and techniques, switching platforms and transmission technologies. In this research, the wideband radio technology will be optimized for improve the quality of multimedia service and to be very spectrum-efficient, helping make the most of available spectrum in order to carry large amounts of data traffic quickly and cost-effectively.

 

New Congestion Management Framework for Best-Effort Networks Supporting Multimedia

Ph.D Candidate: Jim Wu
Description:
When packet loss rate exceeds a given threshold, received audio and video become unintelligible. A congested router transmitting multimedia packets,while inflicting a packet loss rate beyond a given threshold, effectively transmits useless packets. Useless packet transmission wastes router bandwidth when itis needed most. We propose an algorithm to avoid transmission of useless multimedia packets, and allocate the recovered  bandwidth to competing TCP flows. We show that the
proposed algorithm can be easily implemented in well-known WFQ and CSFQ fair packet queueing and discarding algorithms. Simulation of a 15-second MPEG-2 video clip over a congested network shows that the proposed algorithm effectively eliminates useless packet transmission, and as a result of that significantly improve throughput and file download times of concurrent TCP connections. For the simulated network, file download time is reduced by 55 % for typical HTML files, 36 % for typical image files, and up to 30 % for typical video files. A peak-signal-to-noise-ratio (PSNR) based analysis shows that the overall intelligibility  of the received video is no worse than that received without the incorporation of the proposed useless packet transmission avoidance algorithm.Our fairness analysis confirms that implementation of our algorithm into the fair algorithms (WFQ and CSFQ) does not have any adverse effect on the fairness performance of the algorithms.

 

QoS Provisioning on 802.11 WLANs

Ph.D Candidate: Alfandika Nyandoro
Description:
We propose a novel architecture to guarantee QoS for real-time multimedia on 802.11 WLANs.  We are currently refinining the architecture and will soon be evaluating its performance through simulation. It is our goal to show the effectiveness of this new architecture by making comparisons with standard 802.11 WLANs.

 

Quality of Service in 3G Wireless Networks

Ph.D Candidate: Albert Yuen-Tai Chung
Description:
The project aims to develop a QoS mapping architecture for 3G wireless systems to seamlessly support end to end QoS over multiple networks each having a different QoS model and service.

 

Rate Feedback Control in TCP/IP Networks

Ph.D Candidate: Adbul Aziz Bin Mustafa
Description:
The main objective of this research is to investigate the benefits of employing rate feedback control scheme in the IP-based Internet. As the current Internet does not provide any quality of service (QoS) guarantees and mostly based on best-effort service,  delay and loss may become uncontrollable resulting in poor application's performance in the end-systems. In this research, we propose a network-based rate feedback control called IP Rate Control (IPRC) for any IP-based networks. The research involves in designing a rate feedback control architecture involving various network entities such as the IP Host, network edge routers and core routers to play a role in regulating the rate of transmitting source based on current network load to minimize end-to-end delay, delay variances (jitter) and loss to improve applications performance running in the end-systems. By employing a queue control in network routers, results  from computer simulations show that IPRC can be very effective in reducing packet delay, jitter and loss even with a small buffer size employed in routers and hence, can improve applications performance and increase network efficiency.

 

SASHA: A Self-Healing Sensor Network Architecture

Ph.D Candidate: Tatiana Bokareva
Description:
SASHA is a self-healing hybrid sensor network architecture, that is inspired by and co-opts several mechanisms from the Acquired Natural Immune System to attain its autonomy, robustness, diversity and adaptability to unknown pathogens, and compactness.
SASHA is envisioned to provide a knowledge plane for the sensors to reason about and respond to various types of network failures.

 

 

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