Network Connectivity Optimization for Device-to-Device Wireless System with Femto Cells

Abstract

The demand for high data rate transmission has triggered the design and development of advanced cellular networks, such as 4th generation long term evolution (LTE) networks. However, their poor coverage and relatively high interference can significantly impair data transmission. Femtocell and device-to-device (D2D) communication are promising solutions that have recently gathered interest. Operating in the licensed spectrum, femtocells provide users with higher capacity and coverage than their earlier designs, and they will be offered by cellular operators to enable high-data-rate local services in future LTE Advanced networks. As an underlay to the cellular networks, D2D communication enables nearby devices to communicate directly with each other by reusing cellular resources, which reduces interference in the cellular network compared with communication through base stations. However, the tight integration of femtocells and D2D communication creates a challenge for existing network design and is less studied in the literature. In this paper, we propose an open-access algorithm for femtocell base stations in D2D LTE-Advanced networks, in order to optimize network connectivity. Additionally, a greedy algorithm is proposed to balance macrocell base stations and femtocell base stations to maximize network connectivity. The simulation results demonstrate the effectiveness of the proposed. Keywords: I.INTRODUCTION The ever-increasing demand of user equipment (UE) and applications in cellular networks for higher data rate transmission has triggered design of new advanced cellular networks such as the 4th generation (4G) long term evolution (LTE) network. Studies show that more than 50% of voice calls and 70% of data traffic originate indoors [1]. The mobile operator faces challenges in providing in-building coverage due to poor indoor radio signal penetration and possibly crowded indoor environments such as shopping malls. In the LTE-Advanced networks, the femtocell approach is a potential solution to support higher data rate and reliable services to the subscribers, while allowing the operator to reduce data traffic on the expensive macrocell networks [1]. Femtocells can be employed as short-range, low-cost, and low-power base stations for providing cellular service within the home and enterprise environments [2]. On the other hand, to better support higher data rate local services, the cellular operator can integrate device-to-device (D2D) communication in future 4G LTE-Advanced cellular networks as an underlay. The D2D network is built by D2D UEs that do not communicate with each other via the base station (BS), which is called evolved NodeB (eNB) in the LTE architecture. In D2D networks, UEs instead communicate directly over one or more hops [3]. Enabling a D2D communication mode in cellular networks can improve system performance through better reuse of radio resources and reduced congestion when several UEs located in the same area want to communicate with each other [3]. The tight integration of femt...

Experimental Study on Graphene/Transition Metal Chalcogenide Based Energy Storage and Conversion

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