Volume 6, Issue 2, January 2011

Finding the Shortest Path for Mobility of Mobile Sensors in K-Covereage Networks by Using Ant Colony Algorithm
[Full Text]

Samira Mahzad and Hamidreza Bakhshi

Abstract— Sensor deployment that guarantees suitable coverage with minimum number of sensors is one of the most important challenges in designing mobile wireless sensor networks. In this paper, we have proposed an optimized solution for finding the shortest path to move sensors by adopting ant colony algorithm. In other words, the proposed algorithm not only guarantees the k-coverage of sensor network, but also reduces the sensor node moving distance which saves the network energy. From the simulation results, it could be seen that the consumed energy of the proposed algorithm is 10 times less than other exist algorithms which can prolong lifetime of network by reducing average moving distance of mobile nodes.


An Efficient Soft Decision Decoding Scheme for the RSCC-coded Cooperative System [Full Text]

Ismail Shakeel and Irfan Ahmed

During the last few years, several authors have studied various types of channel coding and decoding strategies for the cooperative wireless networks.  Published results show that these strategies effectively improve both the data rate and system performance in cooperative schemes such as the decode and forward (DF), where successful decoding at the relay is extremely important to maintain the diversity order of the system. This paper investigates performance of different types of Reed-Solomon coding schemes for cooperative communication and presents an efficient cooperative relaying and iterative decoding scheme for systems employing Reed-Solomon codes concatenated with convolutional codes (RSCC).  The performance of the proposed scheme shows significant gains over the standard DF relay system.


Modeling IP Traffic Streams in IMS Networks Using MMPP
[Full Text]

Sepideh Ghandali, S. Mostafa Safavi

Abstract—The IP Multimedia Subsystem (IMS) defined by 3rd Generation Partnership Project (3GPP) and 3GPP2 [1], provides a platform for the provision of multimedia services with satisfactory quality of service (QOS). QOS is one of the main reasons for the emergence of IMS. Thus, we believe that performance evaluation of IMS-based networks is essential. We propose here traffic modeling and queuing analysis in order to provide a way to select IMS network design parameters, such that performance (QOS) will be satisfied. In this paper we model the traffic in IMS network with Markov Modulated Poisson Process (MMPP) by using LAMBDA algorithm for fitting MMPP to IP traffic and make conclusion on its efficiency. We improve the results by changing the number of MMPP states and make the fitting process more accurate. According to simulations that we carried out using OPNET and MATLAB, our propose model is acceptable.


Arbitrary Dual-Band RLC Circuits [Full Text]

Mohammad Khalaj-Amirhosseini, Mahmoud Moghavvemi and Aliyar Attaran

A new approach to design a dual-band RLC circuits is proposed. In this approach, a single-band circuit is designed
and then converted to a dual-band circuit by substituting its inductors and capacitors for a proper parallel or series LC resonator. The validity of the proposed approach is verified by designing, implementing and measuring a dual-band RLC power divider at frequencies 10 and 20 MHz as well as a dual-band tank circuit. The proposed approach can be used for designing arbitrary dual-band circuits such as narrowband bandpass filters, bandstop filters, power dividers and combiners, phase shifters etc.


Design of Smart Antenna System Using Conjugate Gradient Method [Full Text]

Falih M. Mousa

Abstract-This paper presents, conjugate gradient method (CGM) to adapt the weights vector of the smart antenna system. The radiation pattern of the proposed antenna system is adjusted to emphasize the desired signal by orienting the mainbeam toward it and eliminate the interfering signals perfectly by pointing nulls in their directions. The performance of this system is compared with that of one of the fastest steepest descent adaptive algorithm named recursive least square (RLS) algorithm. The simulation results show that the proposed method approximately three times faster than RLS algorithm and has better output signal resolution.