International Journal of Communications


ISSN: 1998-4480
Volume 12, 2018

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

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Volume 12, 2018


Title of the Paper: Equal-Optimal Power Allocation and Relay Selection Algorithm Based on Symbol Error Probability in Cooperative Communication

 

Authors: Xin Song, Siyang Xu, Minglei Zhang

Pages: 23-30

Abstract: To optimize power allocation and relay selection in a multi-relay cooperative communication network under a joint total power constraint, a low complexity equal-optimal power allocation and relay selection (EOPRS) algorithm is proposed in an Amplify-and-Forward (AF) cooperative network, which minimizes the symbol error probability (SEP). In the proposed algorithm, the equal power allocation among source and relay nodes is conducted. Then, we can derive an equivalent channel gain, which describes the compositive channel characteristics of two phases that are the source node to relay node and the relay node to destination in the cooperative process. With ascending order of the equivalent channel gain, the signal-to-noise ratio (SNR) can be taken as the threshold, and an optimal set of relay nodes is chosen to minimize the symbol error probability only by solving the arranged matrix. By combining with optimal power allocation in the chosen set, the power allocation factors are derived by the Lagrange multiplier and steepest descent methods, and thus the proposed scheme can further reduce the symbol error probability. The proposed algorithm need not know a large quantity of channel statistical information, which leads to a low complexity cost. In different sets of relay nodes, simulation results show that the proposed algorithm has better SEP performance and power efficiency compared with several traditional algorithms. Moreover, the simulation results can further verify the correctness of the theoretical analysis and the effectiveness of the proposed algorithm.


Title of the Paper: Mutual Inductance and Magnetic Force Calculations Between Thick Bitter Circular Coil of Rectangular Cross Section with Inverse Radial Current and Thin Wall Superconducting Solenoid with Constant Azimuthal Current

 

Authors: S. Babic, C. Akyel

Pages: 17-22

Abstract: In this paper we calculate the mutual inductance and the magnetic force between the thick Bitter coil of rectangular cross section with the inverse radial current and the thin wall superconducting solenoid with the constant azimuthal current. The semi-analytical and the analytical expressions of these magnetic quantities are obtained over complete elliptic integrals of the first and second kind as well as Heuman's Lambda function. There is a simple integral which has to be solved numerically by some of numerical integrations. The results of this method are compared by those obtained by the modified filament method for the presented configuration. All results are in an excellent agreement.


Title of the Paper: Performance Comparative Analysis of LOADing-CTP and RPL Routing Protocols for LLNs

 

Authors: Belghachi Mohammed, Feham Mohamed

Pages: 12-16

Abstract: Low Power and Lossy Networks (LLNs) represent one of the interesting research areas in recent years. The IETF ROLL and 6LoWPAN working groups have developed new IP based protocols for LLNs. In LLNs e.g. 6LoWPANs, heavy data traffic causes congestion which significantly degrades network performance. In this paper we study two routing protocols philosophies for low power and lossy networks (LLNs). This study purposes a detailed evaluation of two routing protocols proposed by IETF, RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) and the reactive LOADng-CTP specified by an IETF draft extended with a collection tree for efficient data acquisition in LLNs. We performed checks on control overhead; End to End Delay and Packet delivery ratio for the two protocols related to multipoint-to-point (MP2P), and point-to-multi point (P2MP) traffic flow.


Title of the Paper: The Influence of FWM to the Four-Channel DWDM System

 

Authors: Petr Ivaniga, Tomas Ivaniga

Pages: 7-11

Abstract: In 21st century it is not possible to create optical communication lines without software tools simulating a real network under the given conditions. This article is focused to the FWM (Four-Wave Mixing), which occurs in the DWDM (Dense Wavelength Division Multiplexing) systems. This phenomenon appears in thickening systems and results in crosstalk between channels. In order to influence expression of FWM was created a four-channel DWDM system according to the recommendation ITU-T G.694.1 with the speed of 10 Gbps. The resulting signal was evaluated based on BER (Bit Error Rate) and the connected Q-factor for the channel No.3. The created system shows the influence of the system by the non-linear effect FWM during the compression between the channels.


Title of the Paper: Performance Evaluation of Wireless Routing Protocols for MANET

 

Authors: Yahia Hasan Jazyah, Luai Al Shalabi, Nourhan Hamdy

Pages: 1-6

Abstract: Mobile ad hoc network (MANET) is a wireless local area network (WLA) that has all mobile nodes connected together directly without the need to central points. MANET has several practical applications such as rescuing somebody lost in fire forest, in the battle field where soldiers in front need to communicate and share important information, and in any rescue operations. Nodes (mobile phone, PDA, laptop, etc…) needs to communicate to each other where the transmitting range is limited due to limited energy source, and so nodes need nodes in the middle (neighbor nodes) to act as mediator to relay the coming message to their neighbor nodes in turn. Several routes from sender node (source) to the receiving node (destination) can be found, the source targets to find the minimum cost path to destination; several protocols have been designed to find such route, some of those protocols consume more energy than the others while other protocols cause network overhead but achieves the required task. This project aims to study wireless routing protocols (AODV, DSR, OLSR, and TORA) for MANET showing their advantages, disadvantages and characteristics, several scenarios will be designed using network simulator (OPNET) which will be used to study some metrics such as throughput, delay and network overhead.