LTE Communications and Networks

Femtocells and Antenna Design Challenges

Masood Ur Rehman, Ghazanfar Ali Safdar, Masood Ur Rehman, Ghazanfar Ali Safdar

• Publisher: Wiley
• Year: 2018
• Print ISBN:
  9781119385226
• Edition: 1
• eBook ISBN:
  9781119385257
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

A comprehensive resource to the latest developments of system enhancement techniques of Femtocells, power management, interference mitigation and antenna design

LTE Communications and Networks fills a gap in the literature to offer a comprehensive review of the most current developments of LTE Femtocells and antennas and explores their future growth. With contributions from a group of experts that represent the fields of wireless communications and mobile communications, signal processing and antenna design, this text identifies technical challenges and presents recent results related to the development, integration and enhancement of LTE systems in portable devices.

The authors examine topics such as application of cognitive radio with efficient sensing mechanisms, interference mitigation and power management schemes for the LTE systems. They also provide a comprehensive account of design challenges and approaches, performance enhancement techniques and effects of user's presence on the LTE antennas. LTE Communications and Networks also highlights the promising technologies of multiband, multimode and reconfigurable antennas for efficient design of portable LTE devices. Designed to be a practical resource, this text:

• Explores the interference mitigation, power control and spectrum management in LTE Femtocells and related issues
• Contains information on the design challenges, different approaches, performance enhancement and application case scenarios for the LTE antennas 
• Covers the most recent developments of system enhancement techniques in terms of Femtocells, power management, interference mitigation and antenna design
• Includes contributions from leading experts in the field 

Written for industry professionals and researchers, LTE Communications and Networks is a groundbreaking book that presents a comprehensive treatment to the LTE systems in the context of Femtocells and antenna design and covers the wide range of issues related to the topic.

1
Introduction

Ghazanfar Ali Safdar and Masood Ur Rehman

School of Computer Science and Technology, University of Bedfordshire, Luton, UK

Wireless communication has involved relentless years of research and design and comprises cellular telephony, broadcast and satellite television, wireless networking to today’s 3rd Generation Partnership Project (3GPP) and Long Term Evolution (LTE) technology. However, cellular telephony networks surpass the others in terms of usage [1]. Although cellular networks were designed to provide mobile voice services and low rate mobile data services, data services have excelled voice and findings show that global data traffic has grown by 280% since 2008 and is expected to double annually in the next 5 years [2]. Importantly, it already exceeded those expectations by 2010 by nearly tripling and it is further predicted that by 2020 nearly 1 billion people will access the Internet using a wireless mobile device [3].

The introduction of new or the upgrade of existing wireless standards such as the Institute of Electrical and Electronics Engineers (IEEE) Worldwide Interoperability for Microwave Access (WiMAX) and 3GPP’s LTE have been developed to meet traffic and high data rates. Most of the methods to increase spectrum capacity in practice today are aligned towards; (1) improving the macro layer by upgrading radio access, (2) densifying the macro layer by reducing inter‐site distances and (3) the use of low power nodes to complement the macro layer [4]. Macro layer deployment is a typical approach of deploying Base Station (BS) in proximity to each other covering large distances with reduced handover frequency. Although it is the backbone of most wireless networks, it has proven to be inefficient as it does not guarantee a high‐quality link in situations where the BS and Mobile Station (MS) are relatively far away. Moreover, a BS serving hundreds of contentious users all vying for resources is old fashioned [5]. Researchers indicate that 50% of all voice calls and most of the data traffic, more than 70%, originate indoors [6]. However, indoor users may suffer from a reduced Received Signal Strength (RSS) due to low signal penetration through the walls or attenuation leading to total loss of signal in situations where the distance between transmitter and receiver is large. There is a need to provide solutions for poor indoor coverage to satisfy consumers. According to [5] the solutions to poor indoor coverage can be classified into two types, Distributed Antenna Systems (DAS) and Distributed Radios.

Distributed Antenna Systems comprise a group of Remote Antenna Units (RAU) spaced apart, providing not only enhanced indoor signal quality by significantly reducing transmission distance but also reducing transmit power (the power of the reference signal) [7]. Some of the challenges involved in deploying DAS are the choice of antennas and selecting a suitable location [8, 9]. Distributed radios involve the introduction of smaller cells to complement the deficiencies of the larger macrocell and the gains include an efficient spatial reuse of spectrum [10]. These small cells, which include picocells and microcells, are overlaid in the macrocell to provide voice and data service. Due to the two‐tier nature of its architecture, it is prone to interference that may result in a low Signal to Interference plus Noise Ratio (SINR), throughput and in some cases a total disruption of service. As a result, there is a need to provide interference avoidance and mitigation schemes. Recently, a new distributed form of radio, LTE femtocells, has emerged that promises to be a viable solution to indoor cellular communication.

1.1 Evolution of Wireless and Cellular Communication

Communication has been essential for humanity to interact with one another where distance, quality of communication and high demand have always been important factors. Thus, it has evolved over the recent decades to overcome such factors in which newer and more obstacles have arrived in order to meet these challenges. Mobile communication has gradually evolved in shape of different generations as described next.

1.1.1 1 G

1G stands for the first generation of wireless mobile communication, which was first implemented in North America in the early 1980s. The technology was also known as Analogue Mobile Phone Systems (AMPS) based on an analogue system; that is, where information is transmitted by controlling a continuous transmission signal, such as amplifying signal strength or varying its frequency in relation to actual data. This system mainly provided services such as voice over a set radio frequency. In order for users to communicate, they would have to maintain a large distance from communicating points and use sufficiently large handsets. A mobile user would have to connect to the mobile base station that connects to the MTSO (Mobile Telecommunication Switching Office) that contains an MSC (Mobile Switching Centre) for routing mobile calls. The MTSO is then connected to the PSTN (Public Switch Telephony Network), which is a collection of unified voice‐oriented public telephone networks [11].

1.1.2 2 G

2G stands for the second generation of wireless mobile communication and finished its establishment in the late 1990s. It was based on the Global System for Mobile Communication (GSM). GSM is a digital cellular phone system and it uses a variation of TDMA (time‐division multiple access). 2G introduced digital traffic and voice encoded into digital signals. From its predecessor, it evolved and brought features such as SMS (short messaging service) and the quality of service for voice communication considerably improved [11].

1.1.3 2.5...

Table of contents

• Cover
• Title Page
• Table of Contents
• List of Contributors
• Preface
• 1 Introduction
• Part I: LTE Femtocells
• Part II: Antennas for LTE Femtocells
• Index
• End User License Agreement