Energy-spectral efficient resource allocation and power control in heterogeneous networks with D2D communication

Wireless Networks - Heterogeneous networks (HetNets) provide the demand for high data rates. In this study, we analyze the coexistence of femtocells and device-to-device (D2D) communication with...     

User grouping and power allocation for energy efficiency maximization in mmWave-NOMA heterogeneous networks

Wireless Networks - This paper investigates the application of non-orthogonal multiple access (NOMA) and millimeter-wave (mmWave) transmission in the fifth-generation (5G) of heterogeneous cellular...     

Resource allocation and power control for underlay device-to-device communication in fractional frequency reuse cellular networks

The current state of device-to-device (D2D) communication in the presence of cellular network addresses two major challenges of interference as well as throughput inadequacy. Specifically, a D2D communication underlaying fractional frequency reuse (FFR) cellular network exhibits rather high interferences due to higher occurrence of band crossing within a shared spectrum. However, due to the considerable impact of D2D communications on spectral efficiency and system capacity, the remedy for those issues may include efficient techniques of interference mitigation and average spectral efficiency maximization. In this paper, we propose a resource block (RB) allocation scheme to reduce the co-channel interference by providing and maintaining adequate distance between D2D user equipment (DUE) and cellular user equipment (CUE), and between the macrocell base station and DUEs that are using the same RB. In the proposed scheme, we initially introduce a plan with one omnidirectional and three directional antennas be used to serve the CUE in the inner and outer regions of the FFR cell, respectively. In addition, DUE in each region uses the RBs that are orthogonal to those used by CUE. It is shown that by using two different ranges for inner region of cellular and D2D communication, the overall performance is improved. Furthermore, we formulate an optimization problem for maximizing average spectral efficiency while guaranteeing CUE signal-to-interference-plus-noise-ratio and achieve efficient solutions to the different average spectral efficiency maximization problems. The results demonstrate the efficiency of the proposed scheme. In addition, it is shown that significant improvement in system spectral efficiency is obtained through the optimization of DUE power. That is, the achieved throughput is much higher than that of the random resource allocation and 1.5–2 times of the previous works.     

Flow-based load-balancing architecture for the agile all-photonic network

A novel routing architecture that balances incoming Internet flows over the agile all-photonic network (AAPN) is proposed. The architecture is based on the adaptive highest random weight (adaptive HRW) algorithm proposed to design load-balanced Internet routers. Extensive numerical evaluation of static and adaptive variations of the routing architecture is studied, and their effect on the network performance in terms of packet drop and flow remapping is presented. The architecture can be seen as a combination of adaptive core node scheduling and adaptive load balancing at the edge nodes. It is stateless and can compute routes quickly based on the packet flow identifier.     

Removal of copper(II) from aqueous solution by Jordanian pottery materials

The aim of this work was to assess the possibility of removing some heavy metals from water by a low-cost adsorbent, like Jordanian raw pottery. Five types of raw and modified pottery materials have been investigated. The effects of initial metal concentration, agitation time, pH and temperature on the removal of Cu(II) were studied. A pseudo-first order was used to test the adsorption kinetics. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The effect of solution pH on the adsorption onto pottery was studied in the pH range 1-5. The adsorption was exothermic at ambient temperature and the computation of the parameters, DeltaH, DeltaS and DeltaG, indicated the interactions to be thermodynamically favorable.