Wireless technology has been evolving at a breakneck speed. The total number of
cell-phones in use (as of 2011) was over 6 billion for a 7 billion world population [1]
constituting 87% of the world population. Additionally, with user convenience be-
coming paramount, more and more functions are being implemented wirelessly.
Cognitive radio has emerged as a promising technology for maximizing the utiliza-
tion of the limited radio bandwidth while accommodating the increasing amount of
services and applications in wireless networks. A cognitive radio (CR) transceiver
is able to adapt to the dynamic radio environment and the network parameters to
maximize the utilization of the limited radio resources while providing flexibility in
wireless access. The key features of a CR transceiver are awareness of the radio envi-
ronment (in terms of spectrum usage, power spectral density of transmitted/received
signals, wireless protocol signaling) and intelligence.
The capability of radio waves to provide almost instantaneous distant communications
without interconnecting wires was a major factor in the explosive growth of communica-
tions during the 20th century. With the dawn of the 21st century, the future for communi-
cations systems seems limitless. The invention of the vacuum tube made radio a practical
and affordable communications medium.
This thesis is about wireless communication in shared radio spectrum. Its origin and
motivation is ideally represented by the two quotations from above. In this thesis, the
support of Quality-of-Service (QoS) in cognitive radio networks is analyzed. New
approaches to distributed coordination of cognitive radios are developed in different
spectrum sharing scenarios. The Wireless Local Area Network (WLAN) 802.11 proto-
col of the Institute of Electrical and Electronics Engineers (IEEE) (IEEE, 2003) with
its enhancement for QoS support (IEEE, 2005d) is taken as basis. The Medium Access
Control (MAC) of 801.11(e) is modified to realize flexible and dynamic spectrum
assignment within a liberalized regulation framework.
The General Packet Radio Service (GPRS) allows an end user to send and
receive data in packet transfer mode within a public land mobile network
(PLMN) without using a permanent connection between the mobile station
(MS) and the external network during data transfer. This way, GPRS opti-
mizes the use of network and radio resources (RRs) since, unlike circuit-
switched mode, no connection between the MS and the external network is
established when there is no data flow in progress. Thus, this RR optimiza-
tion makes it possible for the operator to offer more attractive fees.
When joining Siemens in 2001, I also extended my research interest towards radio net-
work planning methodologies. This area of research brought together my personal interest
in mobile communications and in the design of efficient algorithms and data structures.
Between 2001 and 2003, I participated in the EU project Momentum, which was target-
ing the performance evaluation and optimization of UMTS radio networks. I
Following chapter introduces the mobile communication, gives a short history of wireless
communication evolution, and highlights some application scenarios predestined for the
use of mobile devices. Cellular and wireless based systems related to different generations
of mobile communication, including GSM, IS-95, PHS, AMPS, D-AMPS, cdma2000 and
WCDMA are also described by this Chapter. Much attention in this chapter is given
to express the wireless based networks, such as Wi-Fi and WiBro/WiMax, and wireless
broadcasting systems, including DMB, DVB-H, and ISDB-T. We conclude the chapter
with the future vision of mobile communication evolution
The telecommunications industry is undoubtedly in a period of radical change with
the advent of mobile broadband radio access and the rapid convergence of Internet
and mobile services. Some of these changes have been enabled by a fundamental
shift in the underlying technologies; mobile networks are now increasingly based
on a pure Internet Protocol (IP) network architecture. Since the first edition of this
book was published in 2009, a multitude of connected devices from eBook readers
to smartphones and even Machine-to-Machine (M2M) technologies have all started
to benefit from mobile broadband. The sea change over the last few years is only the
beginning of a wave of new services that will fundamentally change our economy, our
society, and even our environment. The evolution towards mobile broadband is one of
the core underlying parts of this revolution and is the focus of this book.
Providing QoS while optimizing the LTE network in a cost efficient manner is
very challenging. Thus, radio scheduling is one of the most important functions
in mobile broadband networks. The design of a mobile network radio scheduler
holds several objectives that need to be satisfied, for example: the scheduler needs
to maximize the radio performance by efficiently distributing the limited radio re-
sources, since the operator’s revenue depends on it.
Currently, the information and communications technology (ICT) industry sector
accounts for about 2–6% of the energy consumption worldwide, and a significant por-
tion of this is contributed by the wireless and mobile communications industry. With
the proliferation of wireless data applications, wireless technology continues to increase
worldwide at an unprecedented growth rate. This has resulted in an increased number
of installed base stations and higher demand on power grids and device power usage,
causing an increased carbon footprint worldwide.
