1. 1
3G and 4G Mobile Telephony
Shao Dan, Lertrusdachakul Intuon, and Mateos Luis
VIBOT
Heriot Watt University, Scotland, UK
Abstract—Mobile communication is one of the hottest areas that are developing
extremely fast in present times, thanks to the advances of technology in all fields of
mobile and wireless communications.
Nowadays the use of 3G mobile communication systems seem to be the standard,
while 4G stands for the next generation of wireless and mobile communications. This
document studies the 3G – 4G background and the vision for the 4G.
We first present a review on the development history, characteristics, status of
mobile communication and related 3G - 4G perspectives. An overall 4G framework
features, showing the basic keys (diversity and adaptability) of the three targets
(terminals, networks, and applications). We present in both external and internal
diversity of each target to illustrate the causes and solutions of the adaptability
feature. Then, the 4G domain of each feature in the framework is discussed from a
technical point, showing techniques and possible research issues for sufficient
support of adaptability. At the end, a summary on 4G visions and some of the issues
this new technology may face.
Introduction
Mobile communications and wireless networks are developing at an incredible speed,
with evidences of significant growth in the areas of mobile subscribers and terminals,
mobile and wireless access networks, and mobile services and applications. [1] The
present time seem to be right to start the research of 4G mobile communications
because of:
•Possibility, now we are using the 3G standardization and the next generation of 4G
is underway to add more capability and adaptability to the mobile communication
technology.
•Necessity: 3G is in use but the capabilities are not enough to the mobile
communication strategy, in which many problems are only partly solved and there
are still many problems left to be solved in the 4G generation.
For 4G, most of the ongoing research can be classified into two different classes:
1) Many of the related 4G research focuses mainly on one specific technical area,
such as distributed computing, mobile agents, multimedia services, or radio air
interfaces, etc.
2) Some pieces of research are interested mainly in 4G scenarios from the
standpoints of service provider or user, or a market analyst, from a less or non-
technical viewpoint.
We are going to present overall visions on the features of 4G mobile communications,
based on a feature.
Third Generation (3G) and Fourth Generation (4G) Features provides a brief
review of the development history and status of mobile communications.
Technical Perspective discusses the adaptability feature of each three targets in
the entire 4G domain from a technical standpoint, in which promising techniques and
possible research issues are proposed.

2. 2
Third Generation (3G) and Fourth Generation (4G) Features
In general, 3G mobile technologies are broadband capabilities with higher data rate
at lower incremental cost than the 2G supporting the large number of voice and data
customers especially in the urban area. It uses 5MHz channel carrier bandwidth to
deliver significant higher data rate around 384 kbps for mobile systems and up to 2
Mbps for stationary systems. The greater capacity includes the spectrum efficiency
improvement which allows users to access global roaming between different 3G
networks. However, there are some issues against these from the 3G providers and
users. For example, 3G mobile services in some countries are still high price, health
effects caused by electromagnetic waves, High input fees for service licenses, lack of
2G mobile user buy-in for 3G wireless service, and lack of coverage because of the
new service, etc.
The International Telecommunication Union has defined the global standard for third
generation wireless communication as the International Mobile Telecommunications-
2000 or IMT-2000. Within IMT-2000, it consists of UMTS, WCDMA, and
CDMA2000 which can be briefly explained as follow: W-CDMA or Wideband Code
Division Multiple Access. It has designed for replacing the 2G GSM network by
providing the higher speed transmission protocol. It is a wideband spread-spectrum
mobile air interface that utilized the direct sequence Code Division Multiple Access
signaling method (CDMA) to achieve higher speed and support more users compared
to Time Division Multiple Access signaling method (TDMA) used by GSM networks.
W-CDMA is different in many aspects from CDMA2000. CDMA2000 transmits on
several pairs of 1.25 MHz radio channel while W-CDMA transmits on a pair of 5 MHz
wide radio channel. W-CDMA provides a different balance in terms of cost, capacity,
performance, density. In the dense cities in Europe and Asia, W-CDMA is better
suited for deployment.
In 4G mobile technologies, the transmission data rate is increased up to 20Mbps. It
promises the smoother streaming video and interactive multimedia, worldwide
roaming, enhanced multimedia, universal access and portable devices and services
at the lower cost than 3G. The global standards for fourth generation wireless
communications are Orthogonal Frequency-Division Multiplexing (OFDM) and Ultra-
wideband (UWB). For OFDM is a discrete multitone modulation which uses a digital
multi-carrier modulation scheme and generates by using fast Fourier transform
algorithm. Since it uses multi-carrier scheme, it is able to cope with severe channel
conditions e.g. multipath and narrowband interference without complex equalization
filters. It is also robust against narrow-band co-channel interference, intersymbol
interference and fading caused by multipath propagation. It provides high spectral
density, low sensitivity to time synchronization errors, and efficient implementation
using FFT. However, it is sensitive to Doppler shift and sensitive to frequency
synchronization problems. Moreover, there is inefficient transmitter power
consumption due to linear power amplifier requirement. While Ultra-wideband (UWB)
uses the radio technology which has bandwidth larger than 500 MHz or 25% of the
centre frequency.
The following table shows the mobile communications development starting from the
first generation mobile telephony to the up coming the fourth generation mobile
telephony. [2]

3. 3
Table 1: Mobile Communication History and Status
Technical Perspective
This section is purposed to discuss mainly about possible topics research and
promising techniques in replacing 3G by 4G. Fig. 1 gives an illustration of the
discussion domain of 4G.
Figure 1: 4G visions in domains
A. Terminals
To date, the “terminal” for accessing mobile services has been the mobile phone.
With the advanced 3G and also the 4G in future, we can expect to see a broadening
of this concept. User interfaces of terminals will vary from traditional keyboard,
display, and tablet, to new interfaces based on speech, vision, touch, soft buttons,
etc. These will be both general-purpose computing and communications devices, and
devices with more specific purposes to serve particular marker segments. There will
Property 1G 2G 2.5G 3G 4G
Starting Time 1985 1992 1995 2002 2010-2012
Driven
Technique
Analog
Signal
Processing
Digital Signal
Processing
Packet
Switching
Intelligent
Signal
Processing
Intelligent
Software Auto
Configuration
Representative
Standard
AMPS, TACS,
NMT
GSM, TDMA GPRS,
I-Mode,
HSCSD,
EDGE
IMT-2000
(UMTS,
WCDMA,
CDMA2000)
OFDM, UWB
Radio
Frequency (Hz)
400M-800M 800M-900M,
1800M-1900M
2G 3G-5G
Bandwidth
(bps)
2.4K-30K 9.6K-14.4K 171K-384K 2M-5M 10M-20M
Multi-address
Technique
FDMA TDMA, CDMA FDMA, TDMA,
CDMA
Cellular
Coverage
Large area Medium area Small area Mimi area
Core Networks Telecom networks Telecom
Networks,
Some IP
networks
All-IP networks
Service Type Voice,
Mono-
service,
Person-to-
person
Voice, SMS,
Mono-media,
Person-to-
person
Data
service
Voice, Data,
Some
Multimedia,
Person-to-
machine
Multimedia,
Machine-to-
machine

4. 4
still be recognizable mobile phones. But many of these will have larger screens to
display Internet pages or the face of the person being spoken to. There will be
smaller "smart-phones" with limited web browsing and e-mail capabilities. The
addition of mobile communications capabilities to laptop and palmtop computers will
speed up the convergence of communications and computing, and bring to portable
computing all the functions and features available on the most powerful desktop
computers. There will be videophones, wrist communicators, palmtop computers,
and radio modem cards for portable computers. Innovative new voice based
interfaces will allow people to control their mobile communication services with voice
commands.
B. Networks
Worldwide roll-out of 3G networks was delayed in some countries by the enormous
costs of additional spectrum licensing fees. In many parts of the world 3G networks
do not use the same radio frequencies as 2G, requiring mobile operators to build
entirely new networks and license entirely new frequencies. So that a number of
spectrum allocation decisions, spectrum standardization decisions, spectrum
availability decisions, technology innovations, component development, signal
processing and switching enhancements and inter-vendor cooperation have to take
place before the vision of 4G will materialize.
C. Applications
The emerging applications for 3G and 4G wireless systems typically require highly
heterogeneous and time varying quality of service from the underlying protocol
layers. So adaptability will be one of the basic requirements to the development and
delivery of new mobile services. Promising techniques and possible topics may
include:
Mobile application should refer to a user’s profile so that it can be delivered in a way
most preferred by the subscriber, such as context-based personalized services. This
also brings the applications with adaptability to terminals that are moving in varying
locations and speeds. Techniques such as adaptive multimedia and unified
messaging take the terminal characteristics into account and ensure that the service
can be received and run on a terminal with the most suitable form to the host type.
Conclusion
After a brief review of the history of mobile communications, the 3G and 4G mobile
communications feature were described.
The 4G framework is based on the key concept of integration, and it has the
following characteristics:
1) The core features of 4G are described as diversity and adaptability of the targets.
2) The feature of diversity includes both external and internal diversity, in which
adaptability is caused by external diversity and is solved by internal diversity.
Technical perspectives are presented and some techniques with its possible research
issues of 4G.
References
[1] B.G. Evans and K. Baughan, “Visions of 4G,” Electronics & Communication
Engineering Journal, Vol. 12, No. 6, pp. 293–303, Dec. 2000.
[2] C. R. Casal, F. Schoute, and R. Prasald, “A novel concept for fourth generation
mobile multimedia communication,” in 50th Proc. IEEE Vehicular Technology
Conference, Amsterdam, Netherlands, Sep. 1999, Vol. 1, pp. 381–385.

5. 5
Appendix
Gannt chart.