Jia Uddin, is a Ph.D. candidate in Computer Engineering in University of Ulsan, South Korea. He received the B.Sc. degree in Computer & Communication Engineering from International Islamic University Chittagong (IIUC), Bangladesh, in 2005, the M.Sc. degree in Electrical Engineering emphasis on Telecommunications from Blekinge Institute of Technology (BTH), Sweden, in 2010. He is an Assistant Professor in Faculty of Science & Engineering at IIUC, Bangladesh. His research interests include Wireless Networks, Ad-Hoc Networks and Parallel Computing.
Abstract: The IEEE 802.11b standard is a protocol for proper interconnection of data communication tool using the wireless transmission in the Local Area Network (LAN). It includes the physical and the Media Access Control (MAC) layers of the ISO seven-layer network model. Therefore, investigating its performance with different ad-hoc network environment is necessary. Previously, a number of studies investigate the performance of various routing protocols using different evaluation methods with simulators, resulting to different outcomes. Thus, there is a need to expand the spectrum to take into consideration the effects of file size, numbers of nodes and mobility that were neglected in a specific environment and compare them with real life scenario MANET network. This paper present analysis results for the performance evaluation of transmitting FTP file with AODV routing protocol in OPNET modeler and real life network for several scenarios with 802.11b wireless networking transmission method. Simulation results demonstrate that the scenarios with small amount of fixed and mobile nodes shows better performance. The overall network performance automatically degrades with the increment of number of nodes as well as increment of packet size.
Abstract: The IEEE 802.11b standard is a protocol for proper interconnection of data communication tool using the wireless transmission in the Local Area Network (LAN). It includes the physical and the Media Access Control (MAC) layers of the ISO seven-layer network model. Therefore, investigating its performance with different ad-hoc network environment is necessary. Previously, a number of studies investigate the performance of various routing protocols using different evaluation methods with simulators, resulting to different outcomes. Thus, there is a need to expand the spectrum to take into consideration the effects of file size, numbers of nodes and mobility that were neglected in a specific environment and compare them with real life scenario MANET network. This paper present analysis results for the performance evaluation of transmitting FTP file with AODV routing protocol in OPNET modeler and real life network for several scenarios with 802.11b wireless networking transmission method. Simulation results demonstrate that the scenarios with small amount of fixed and mobile nodes shows better performance. The overall network performance automatically degrades with the increment of number of nodes as well as increment of packet size.
Abstract: Cooperative spectrum sensing has a great impact to increase the
performance for detecting the Primary User (PU) signal over
single node sensing. Recent developments in multiple antenna
techniques adjoin a new dimension in spectrum sensing. In this
paper, we have proposed multi antenna based signal detection
considering cooperative approach to minimize sensing and
reporting time. The simulation is accomplished in Rayleigh fading
channel with different combining methods to obtain local decision
where every cognitive radio user contains multiple antennas. In
addition, decision fusion of cognitive radio users is considered
in the simulation, where fusion is done with general fusion rule
for showing global probability of detection. The significance and
efficiency of the proposed method is justified through analysis
and simulation for both local as well as global sensing in term of
probability of detection or miss detection, false alarm, sensing time
and reporting time. The experimental results demonstrate that the
proposed method improves the performance maintaining quality
of service as compared with the conventional system.
Abstract: Localization and mapping are very important for safe movement of robots. One possible way to assist with this functionality is to use laser scan matching. This paper describes a method to implement this functionality. It is based on well-known random sampling and consensus (RANSAC) and iterative closest point (ICP). The proposed algorithm belongs to the class of point to point scan matching approach with its matching criteria rule. The performance of the proposed algorithm is examined in real environment and found applicable in real-time application.
Abstract: Mobile ad hoc network consists of wireless mobile nodes, where nodes convey message to each
other without any pre-established infrastructure or centralized control. The wireless ad hoc
network eradicates the complications which may arise while setting up the infrastructure. The
mobility model is crucial when evaluating routing protocols exhibition in mobile ad hoc
networks. Two parameters are very important when dealing with mobility behavior of mobile
nodes: pause time and maximum speed. In this paper, we investigate the effect of mobility
model on state of art proactive and reactive routing protocols for mobile ad hoc networks. The
Reference Point Group Mobility model and the Random Way Point Mobility model represent
the group and an entity mobility model used in this simulation to compare and analyze the
performance of the routing protocols. In this study the performance analysis and comparison of
the routing protocols under different mobility scenarios are evaluated in Network Simulator 2.
Four important performance metrics of ad hoc networks including average end-to-end delay,
packet delivery ratio, normalized routing load or overhead and average number of hops are
considered. Based on the empirical study, both propagation models cause different impact on
the AODV and DSDV routing protocol. Where, AODV performs better with the RPGM than
the RWPM with respect to end-to end-delay, normalized routing load and average number of
hops. However, in delivery ratio AODV performs better with the RWPM than the RPGM. On
the other hand, AODV and DSDV protocols have similar results in deliver y ratio and average
number of hops and DSDV performed better than AODV in normalized routing and end-to-end
delay. Finally, it can be concluded that no protocol significantly outperforms the other in all
scenarios and matrics considered.
Abstract: The emergence of Wi-MAX has engrossed important interest from all fields of wireless communications. The Wi-MAX can also be considered as a core technology in the implementation of other networks such as Wireless Sensor Network. Developing an understanding of the Wi-MAX system can be best achieved by looking at a model of the Wi-MAX system. This paper presents model building of the Wi-MAX Physical layer using computer Matlab R2011a version. This model is a useful tool for BER performance evaluation for the real data communication by the Wi-MAX Physical layer under different channel encoding rates, digital modulation schemes and channel conditions. With the performance investigation of the system, the modulation schemes BPSK, QPSK and 16QAM are introduced beside ½ rated convolutional encoder under AWGN. The model presented in this paper built with the Physical Layer using convolutional encoding rate of ½ and transmitted with 256 carrier OFDM symbols. Computer simulation results on BER over an Additive White Gaussian Noise (AWGN) channel demonstrate that the proposed system outperforms with BPSK modulation technique as compared to other digital modulation schemes and the system is highly effective to combat inherent interferences under. It has been anticipated from the simulation study with real data that the performance of the communication system degrades with the increasing of noise power.
Abstract: Mobile Ad-hoc Networks (MANETs) have already opened a new point of view in the field of wireless networks, which includes hundreds and thousands of nodes. The wireless nodes are communicating without the need of any kind of neither infrastructure like the base stations or routers, nor centralized administration. Wireless nodes are free of moving anytime, anywhere. Therefore, MANETs need to have dynamic routing protocols. The MANET routing protocols are divided into several different categories such as Proactive, Reactive, and Hybrid. There arenumerous performance metrics are used to compare the routing protocols. Each of them has its own attributes and well for specific area such as throughput, jitter, packet delivery ratio, average number of hops, route discovery time, and end-toend delay, etc. In this paper, two well known routing protocols including OLSR and AODV were evaluated using the OPNET 17.1 simulator under the medium load traffic size in FTP protocol. The Random Waypoint mobility model is used as pattern of mobility. As performance metrics the average throughput and average network load are examined in different number of nodes, file sizes, and node speeds.
Abstract: Underwater acoustic sensor networks (UASNs)
consist of movable and stationary nodes, which usually
communicate using the acoustic channel . Underwater
acoustic communication networks are particularly susceptible
to malicious attacks due to the high transmission power
requirements, rapidly changing channel characteristics,
multi- path echoes, high bit error rates, high ambient
noise, high and varying propagation delays, and low
bandwidth of acoustic channels. The distinctive characteristics
of the underwater acoustic communication channel and the
difference between underwater sensor network and their
ground-based counterparts require the development of
efficient and reliable security mechanisms. In order to achieve
the optimal performance an underwater network must be
able to sense its ambient environment and react by
adapting its communication parameters smoothly. This paper
presents a complete analysis of safety measurements for
UASNs and the research challenges for secure
communication.
Abstract: In the real scenarios, network utilization widely depends on the background traffic and the number of active users. This paper presents the effect of background traffic on the QoS of foreground traffic by varying the utilization of LAN devices, server, and bandwidth. We designed a WAN (Wide Area Network) using the OPNET simulator, which consists of different Local Area Networks (LANs) located in different cities. We considered a foreground GSM quality voice traffic, and FTP heavy and video conference background traffic. The experimental results demonstrated that the channel bandwidth utilization has much effect on the QoS of foreground traffic. In addition, heavy background traffic highly affects the QoS of foreground traffic due to the network congestion.
Abstract: Multicarrier Code Division Multiple Access Schemes (MC-CDMA) have been recently introduced in existing CDMA based systems to improve security, data transmission rate and to minimize Inter Symbol Interference (ISI). CDMA experiences severe multipath fading which badly affects its performance. By transmitting identical narrowband Direct- Sequence (DS) waveforms using frequency diversity, in parallel with a number of subchannels, multipath fading could be minimized. Implementation of this multicarrier modulation technique in CDMA system is known as multicarrier CDMA. We have shown that in Rayleigh Fading Channel, due to multicarrier modulation, when one subcarrier goes deep fade, another subcarrier remains safe. Therefore MC-CDMA can combat multipath fading better than CDMA and signal can be received in low bit error rate (BER).
Abstract: This paper presents an approach of image signal denoising that is based on the image domain minimization of an estimate of the Mean Square Error (MSE)-Stein's Unbiased Risk Estimate (SURE) between the clean image and the denoised one. The key position is that we have at my consent a very particular, statistically unbiased, MSE estimate-Stein's unbiased risk estimate-that depends on the noisy image alone, not on the clear one. Here using an Undecimated Wavelet Transform (UWT) that the denoising process can be expressed as a linear combination of the elementary denoising process named Linear Expansion of Threshold (LET). Combining with the SURE and LET principles, a fast and proficient result is obtained by executing a simple threshold on the undecimated Haar wavelet coefficients that results SURELET theory has a massive perspective.
Abstract: The advancement in broadband and mobile communication has given many privileges to the subscribers including high data rate, voice and video application in economical rates with better quality of service (QoS). Wi-MAX has potential success in its Line-of-Sight (LOS) and Non Line-of-Sight (NLOS) conditions which operates below the 11 GHz frequency. However, estimation of path loss is very important issue in the initial deployment of wireless networks and cell planning. Different path loss propagation models are already been proposed to predict the propagation loss in Wi-MAX, but till now it is in research as no one can ensure better performance in different network scenarios. In this paper we evaluated the performance of state-of-art propagation models in different network environments including urban, sub-urban and rural to observe the impact of receiver antenna heights. Experimental results show that selecting a suitable receiving antenna height in a specific area is a considerable term as it greatly influences on the path loss of a propagation model.
Abstract: Attenuated side lobe peak in the range of around ~-45dB is required in many applications
of signal processing and measurements. However, the problem is usual window based FIR filter
design lies in its side lobes amplitudes that are higher than the requirement of application. We
propose a modified Lanczos window function by heuristic by examining the Lanczos window,
which has better performance like equiripple, minimum side lobe compared to the several
commonly used windows. The proposed window has slightly larger main lobe width of the
commonly used Hamming window, while featuring 5.1~18.5 dB smaller side lobe peak. The
proposed modified Lanczos window maintains its maximum side lobe peak about -55.2~-51.9 dB
compared to -39~-36.7 dB of Hamming window for M=10~14, while offering roughly equal main
lobe width. Our simulated results also show significant performance upgrading of the proposed
modified Lanczos window compared to the Kaiser, Gaussian, and Lanczos windows. The proposed
modified Lanczos window also shows better performance than Dolph-Chebyshev window. Finally,
the example of designed low pass FIR filter confirms the efficiency of the proposed modified
Lanczos window.
Abstract: The demand of high volume data communication over the internet is mounting day by day. In general, the performance of a communication system depends on the loss of data packets. It happens as there are multiple paths exist in wireless networks. For the reliable and secure data communication over Internet Transmission Control Protocol (TCP) is playing a significant role. On the development of TCP, a number of approaches are already designed and tested in the communication system. Generally, TCP congestion parameters are set in sender site in a communication system. In this paper, we investigate the download system performance tuning the TCP congestion parameters at the Ethernet port of receiver side. Based on the experimental study, it is concluded that tuning TCP parameters at receiving side improves the download system performance by reducing packet loss, increasing download speed and maintain stable I/O and time/sequence graphs.
Abstract: Demodulation of received signals for a known channel parameters over Rayleigh fading channel is done by BEM (Bayesian Estimation Maximization) algorithm using MAP (Maximum A Posteriori) Probability decisions. Simulation results were produced using this demodulator for the specified mobile - satellite based trans-receiver system to find the BER (Bit Error Rate). Comparisons are made to that of a QPSK (Quadrature Phase Shift Keying) demodulator to show that the performance is better in our designed demodulator with respect to BER. These simulation results are produced using Matlab platform.
Abstract: In this research we have explored the consequences of
increase in number of nodes on the overall performance of
Geographical Routing Protocol (GRP) which is at present
covering an enormous demand in the field of Mobile Ad-Hoc
Networks (MANETs). To think about a wireless network without
having any sorts of infrastructures, MANETs are such examples
which are usually set up to serve a specified or special purpose on
a temporary basis within a certain passage of time. Due to its lots
of applications in the various fields of human endeavor, the
immense significance of it can hardly be expressed in words in
modern times. Thus, before deploying any mobile network, a
proficient routing protocol has become a fundamental and vital
issue. In order to observe the performance of GRP protocol, we
have carried out simulation by varying the number of mobile
nodes in different network scenarios using the OPNET
(Optimized Network Engineer Tool) Modeler 14.0. The
experimental results demonstrate that for a fixed size network
area with varying network density, the GRP routing protocol
shows comparatively lower delay than AODV routing protocol.
But it shows inverse characteristics curve for throughput and
load compare to the AODV. However, from any network always
expects less delay and concurrently want large throughput.
Therefore, till now no routing protocol shows optimum
performance in all MANET scenarios.
Abstract: This paper proposes a model of variable rate
automatic microcontroller based irrigation system. Solar power
is used as only the source of power to control the overall system.
Sensors are placed on the paddy field and these sensors
continuously sense the water level and give the message to the
farmer informing the water level. Without visiting the paddy
fields, farmers can get the information about the water level.
Based on the water level, a farmer can control the motor by
sending a message from his cellular phone even from a remote
place. However, if the water level reaches to the danger level;
the motor will automatically start without confirmation of
farmer to ensure the proper water level in the site. At the end of
this paper, a complete hardware implementation of this
proposed automated irrigation system is presented.
Abstract: The performance of a TCP-based client-server system greatly
depends on the loss of data packets due to lack in the congestion control
algorithm. In this paper, we investigate the impact of tuning the congestion
control parameters in a TCP-based client-server system by considering the
commonly used Westwood algorithm and congestion window size at the
Ethernet port of the client device. For a large file located in a remote server, the
experimental results demonstrate that tuning the TCP Westwood algorithm and
TCP congestion window improve the download performance significantly by
reducing packet drop and increasing the download speed
Abstract: The IP backbone in IMANET has some constraints such as lack of security, high congestion, inefficient for massive data communication. In this paper, we propose a Multi-Protocol Label Switch (MPLS) backbone IMANET, where conventional IP backbone is replaced by MPLS backbone. In our proposed model, a number of MANET gateways support mismatch of routing protocols and data packets format in different networks. Experimental results demonstrate that the proposed model outperforms the conventional IP backbone IMANET by significantly increasing throughput and reducing network congestion and network latency.
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