IINNTTRROODDUUCCTTIIOONN

The approaching 4G (fourth generation) mobile commu-nication systems are projected to solve still-remaining

problems of 3G (third generation) systems and to providea wide variety of new services, from high-quality voice tohigh-definition video to high-data-rate wireless channels.The term 4G is used broadly to include several types ofbroadband wireless access communication systems, notonly cellular telephone systems. One of the terms used todescribe 4G is MAGIC—Mobile multimedia, Anytime any-where, Global mobility support, Integrated wireless solu-tion, and Customized personal service. As a promise forthe future, 4G systems, that is, cellular broadband wire-less access systems, have been attracting much interestin the mobile communication arena. The 4G systems notonly will support the next generation of mobile service, butalso will support the fixed wireless networks.

This paper presents an overall vision of the 4G fea-tures, framework, and integration of mobile communica-tion. The features of 4G systems might be summarizedwith one word—integration. The 4G systems are aboutseamlessly integrating terminals, networks, and applica-tions to satisfy increasing user demands.

The continuous expansion of mobile communicationand wireless networks shows evidence of exceptionalgrowth in the areas of mobile subscriber, wireless net-work access, mobile services, and applications. An esti-mate of 1 billion users by the end of 2003 justifies thestudy and research for 4G systems.

HHIISSTTOORRYY

The history and evolution of mobile service from the 1G(first generation) to fourth generation are discussed in

this section. Table 1 presents a short history of mobiletelephone technologies.

This process began with the designs in the 1970s thathave become known as 1G. The earliest systems were

implemented based on analog technology and the basiccellular structure of mobile communication. Many funda-mental problems were solved by these early systems.Numerous incompatible analog systems were placed inservice around the world during the 1980s.

The 2G (second generation) systems designed in the1980s were still used mainly for voice applications butwere based on digital technology, including digital signalprocessing techniques. These 2G systems provided cir-cuit-switched data communication services at a lowspeed. The competitive rush to design and implementdigital systems led again to a variety of different andincompatible standards such as GSM (global systemmobile), mainly in Europe; TDMA (time division multipleaccess) (IS-54/IS-136) in the U.S.; PDC (personal digitalcellular) in Japan; and CDMA (code division multipleaccess) (IS-95), another U.S. system. These systemsoperate nationwide or internationally and are today'smainstream systems, although the data rate for users inthese system is very limited.

During the 1990s, two organizations worked to definethe next, or 3G, mobile system, which would eliminateprevious incompatibilities and become a truly global sys-tem. The 3G system would have higher quality voicechannels, as well as broadband data capabilities, up to 2Mbps. Unfortunately, the two groups could not reconciletheir differences, and this decade will see the introduc-tion of two mobile standards for 3G. In addition, China ison the verge of implementing a third 3G system.

An interim step is being taken between 2G and 3G, the2.5G. It is basically an enhancement of the two major 2Gtechnologies to provide increased capacity on the 2G RF(radio frequency) channels and to introduce higherthroughput for data service, up to 384 kbps. A veryimportant aspect of 2.5G is that the data channels areoptimized for packet data, which introduces access tothe Internet from mobile devices, whether telephone,PDA (personal digital assistant), or laptop.

However, the demand for higher access speed multi-media communication in today's society, which greatly

December 2002 • Volume 1, Number 1 11

4G Features

Jawad Ibrahimjaibrahi@bechtel.com

Issue Date: December 2002

depends on computer communication in digital format,seems unlimited. According to the historical indication ofa generation revolution occurring once a decade, thepresent appears to be the right time to begin theresearch on a 4G mobile communication system.

44GG

This new generation of wireless is intended to comple-ment and replace the 3G systems, perhaps in 5 to 10

years. Accessing information anywhere, anytime, with aseamless connection to a wide range of information andservices, and receiving a large volume of information, data,pictures, video, and so on, are the keys of the 4G infra-structures. The future 4G infrastructures will consist of aset of various networks using IP (Internet protocol) as acommon protocol so that users are in control because theywill be able to choose every application and environment.

Based on the developing trends of mobile communi-cation, 4G will have broader bandwidth, higher data rate,and smoother and quicker handoff and will focus onensuring seamless service across a multitude of wirelesssystems and networks. The key concept is integrating the4G capabilities with all of the existing mobile technolo-gies through advanced technologies.

Application adaptability and being highly dynamic arethe main features of 4G services of interest to users.

These features mean services can be delivered and beavailable to the personal preference of different usersand support the users' traffic, air interfaces, radio envi-

ronment, and quality of service. Connection with the net-work applications can be transferred into various formsand levels correctly and efficiently. The dominant meth-ods of access to this pool of information will be themobile telephone, PDA, and laptop to seamlessly accessthe voice communication, high-speed information servic-es, and entertainment broadcast services. Figure 1 illus-trates elements and techniques to support the adapt-ability of the 4G domain.

The fourth generation will encompass all systems fromvarious networks, public to private; operator-drivenbroadband networks to personal areas; and ad hoc net-works. The 4G systems will interoperate with 2G and 3Gsystems, as well as with digital (broadband) broadcastingsystems. In addition, 4G systems will be fully IP-basedwireless Internet.

This all-encompassing integrated perspective showsthe broad range of systems that the fourth generationintends to integrate, from satellite broadband to high alti-tude platform to cellular 3G and 3G systems to WLL (wire-less local loop) and FWA (fixed wireless access) to WLAN(wireless local area network) and PAN (personal area net-work), all with IP as the integrating mechanism.

With 4G, a range of new services and models will beavailable. These services and models need to be furtherexamined for their interface with the design of 4G sys-tems. Figures 2 and 3 demonstrate the key elements andthe seamless connectivity of the networks.

Bechtel Telecommunications Technical Journal 12

Technology 1G 2G 2.5G 3G 4G

Design Began 1970 1980 1985 1990 2000

Implementation 1984 1991 1999 2002 2010?

Service Analog voice, Digital voice, Higher capacity, Higher capacity, Higher capacity,synchronous data short packetized data broadband data completely IP-to 9.6 kbps messages up to 2 Mbps oriented, multimedia,

data to hundredsof megabits

Standards AMPS, TACS, TDMA, CDMA, GPRS, EDGE, WCDMA, Single standardNMT, etc. GSM, PDC 1xRTT CDMA2000

Data Bandwidth 1.9 kbps 14.4 kbps 384 kbps 2 Mbps 200 Mbps

Multiplexing FDMA TDMA, CDMA TDMA, CDMA CDMA CDMA?

Core Network PSTN PSTN PSTN, Packet network Internetpacket network

Table 1. Short History of Mobile Telephone Technologies

Legend:

1xRTT = 2.5G CDMA data service up to 384 kbpsAMPS = advanced mobile phone serviceCDMA = code division multiple accessEDGE = enhanced data for global evolutionFDMA = frequency division multiple accessGPRS = general packet radio system

GSM = global system for mobileNMT = Nordic mobile telephonePDC = personal digital cellularPSTN = pubic switched telephone networkTACS = total access communications systemTDMA = time division multiple accessWCDMA = wideband CDMA

December 2002 • Volume 1, Number 1 13

Figure 2. Seamless Connections of Networks (Ref. 2)

Figure 1. 4G Visions (Ref. 1)

Users Ter minals Air Inter faces

AccessPoints

MobileAccesses

Fixed Backbone Applications

4G Mobile Communications

Users Ter minals Air Inter faces

AccessPoints

MobileAccesses

Fixed Backbone Applications

4G Mobile Communications

Users Ter minals Air Inter faces

AccessPoints

MobileAccesses

Fixed Backbone Applications

4G Mobile Communications

Short Range PAN/LAN/ WAN/MAN

BroadcastDVB/DAB

CellularGSM 2G+

CellularUMTS 3G

WLANHIPERLAN

Cellular4G

Connection

Layer

IP BasedCore Network

Legend:PAN = Personal Access NetworkLAN = Local Area NetworkWAN = Wide Area NetworkDVB = Digital Video Broadcast

DAB = Digital Analog BroadcastMAN = Metropolitan Area NetworkUMTS = Universal Mobile Telecommunications SystemWLAN = Wireless Local Area Network

Short Range PAN/LAN/ WAN/MAN

BroadcastDVB/DAB

CellularGSM 2G+

CellularUMTS 3G

WLANHIPERLAN

Cellular4G

Connection

Layer

IP BasedCore Network

Legend:PAN = Personal Access NetworkLAN = Local Area NetworkWAN = Wide Area NetworkDVB = Digital Video Broadcast

DAB = Digital Analog BroadcastMAN = Metropolitan Area NetworkUMTS = Universal Mobile Telecommunications SystemWLAN = Wireless Local Area Network

CCOONNCCLLUUSSIIOONN

As the history of mobile communications shows,attempts have been made to reduce a number of

technologies to a single global standard. Projected 4Gsystems offer this promise of a standard that can beembraced worldwide through its key concept of integration.

Future wireless networks will need to support diverseIP multimedia applications to allow sharing of resourcesamong multiple users. There must be a low complexity ofimplementation and an efficient means of negotiationbetween the end users and the wireless infrastructure.The fourth generation promises to fulfill the goal of PCC(personal computing and communication)—a vision thataffordably provides high data rates everywhere over awireless network.

RREEFFEERREENNCCEESS

1. B. G. Evans and K. Baughan, "Visions of 4G,"Electronics and Communication EngineeringJournal, Dec. 2002.

2. H. Huomo, Nokia, "Fourth Generation Mobile," presented at ACTS Mobile Summit99, Sorrento,Italy, June 1999.

3. J. M. Pereira, "Fourth Generation: Now, It IsPersonal," Proceedings of the 11th IEEEInternational Symposium on Personal, Indoor andMobile Radio Communications, London, UK,September 2000.

BBIIOOGGRRAAPPHHYY

Jawad Ibrahim is an RFengineer in the RF DesignDepartment at BechtelTelecommunications. Heis actively involved in bothRF planning work forclients and equipmenttesting in the Bechtel TDR(Training, Demonstration,and Research) Laboratoryin Frederick, Maryland.Jawad has also participat-ed in audits for OSSs(operation support sys-

tems) for clients.Previously, at Teligent, Jawad was involved in NOC (net-

work operations center) testing and certification. He hasextensive experience in RF design, both mobile and fixed.He also has worked in wireline systems, both switchingand transmission.

Jawad holds a Bachelor of Science degree in ComputerInformation Systems and Network Engineering fromStrayer University and is working toward his Master'sdegree in Telecommunication and Computer InformationSystems at George Washington University.

Bechtel Telecommunications Technical Journal 14

Jawad Ibrahim

Figure 3. Key Elements of 4G Vision (Ref. 3)

UbiquitousMobileAccess

FullyConverged

Services

DiverseUser

Devices

AutonomousNetworks

SoftwareIndependency

2010

UbiquitousMobileAccess

FullyConverged

Services

DiverseUser

Devices

AutonomousNetworks

SoftwareIndependency

2010