The Evolution of 3G Wireless Technologies

There are several different types of 3G wireless technologies that are defined and planned to be up and working today.  There are also several that are on their way.  These are successors of course, to the previous 2G technologies that dominated the airwaves.


CDMA2000 is the successor to IS-95 systems.  CDMA2000 provides a definition for two different options for 3G technologies.  IT Differs in the amount of the frequency spectrum that is used.  The Spreading Rate (SR1) operates in the 1.25 MHz band and is known as a 1x system.  Another proposal exists also which is referred to as 1xEV-DO.  The 1xEV-DO (1x Evolution for Data Optimized) solution is a data-only solution that enables a bandwidth of 2Mbps without any mechanism for voice.  This is the type of data rate that we are all familiar with, the 3G 2Mbps speed of data connection.

The Universal Mobile Telecommunications System (UMTS)

The Universal Mobile Telecommunications System (UMTS) is a successor to GSM/GPRS systems.  There are also two options for the UMTS networks.  The Frequency Division Duplex (FDD) option uses spectrum bands which are paired together.  For example, two different 5 MHz bands are used for uplink and downlink.  The Time Division Duplex (TDD) option uses an unpaired band.  In other words, the same 5 MHz band is shared between uplink and downlink for TDD.

Universal Wireless Consortium for IS-136 systems

The UWC-136 (Universal Wireless Consortium for IS-136 systems) was originally considered to be the evolution for IS-136 systems.  However, the IS-136 system operators eventually decided to follow the path of CDMA2000 or UMTS.

Why did we need 3G Technology?

Back in the late 1990’s, when most of the readers out there were still playing in the sandbox, the International Telecommunication Union (ITU) set the requirements for the next generation of wireless networks (that is why they are called Third Generation (3G)).  One of the many many requirements is to reach peak data rates of at least 2 Mbps.  This is more relvant to the Downlink since the majority of traffic comes from the server to the client in the Internet World.

To meet this new high speed requirement, the 2nd generation wireless networks came up with several different evolutions before eventually being replaced.  The GSM evolution includes GPRS and EDGE, which provide packet data services and represent intermediate solutions until a UMTS Release 99 System is deployed.  The 1xEV-DO is one possible evolution path from 1xRTT, and HSDPA is a Release 5 feature of UMTS.

So how did UMTS Evolve?

UMTS is the network of choice these days.  Yes, UMTS is 3G…If you haven’t caught that yet.  For those nerds out there that are curious, the evolution of UMTS has progressed over the years in the following fashion:

UMTS Release 99

  • 2 Mbps theoretical peak packet data rates
  • 384 kbps (practical)

UMTS Release 5

  • HSDPA (14 Mbps downlink theoretical)
  • IMS (IP Multimedia Subsystem for multimedia)
  • UP UTRAN (for scalability and lower cost)

UMTS Release 6

  • HSUPA (up to 5.76 Mbps uplink)
  • MBMS (Multimedia Broadcast Multicast Service)

UMTS Release 7

  • Multiple Input Multiple Output (MIMO) Antenna Systems

The Evolution of Wireless Technologies

Cellular systems have come a long way since their introduction in the 1980s.  The evolution progressed from First Generation (1G) systems to Second Generation (2G) systems.  Now, Third Generation (3G) systems are being deployed.

1G systems introduced the cellular concept, in which multiple antenna sites are used to serve an area.  The coverage of a single antenna site is called a cell.  A cell can serve a certain number of users, and higher-system capacity can be achieved by creating more cells with smaller coverage areas.  One distinguishing factor of 1G systems is that they make use of analog radio transmissions, so user information, such as voice, is never digitized.  As such, they are best suited for voice communications, since data communications can be cumbersome.

The migration of 1G analog technologies toward 2G technologies began in the late 1980s and early 1990s.  The primary motivation was increased system capacity.  This was achieved by using more efficient digital radio techniques that enabled the transmission of digitized compressed speech signals.  These digital radio techniques also supported data services with data rates as high as 14,400 bits per second (14.4 kbps) in some systems.  2G data communication is typically done using circuit-switched techniques, which are not very efficient for sending packet data such as that sent on the Internet.  This inefficiency makes the use of wireless data more expensive f or the end user.

The next step in the evolution is from 2G to 3G, which started in the year 2000.  The new key feature of 3G systems is the support of high-speed data services with data rates as high as 2 million bits per second (2 Mbps).  Data can be transferred using packet-switching techniques rather than the circuit-switching approach.  Therefore, it is more efficient and less expensive.  This opens up the possibility of cost-effective Internet access, access to corporate intranets, and a host of multimedia services.

If you want to read more about the evolution of wireless networks and WCDMA radio networks in general, please stay tuned for the next several editions where I will go into details.

Upcoming including but not limited to:

  • Physical layer functions
  • W-CDMA Channels
  • Basic call setups
  • Data session setups
  • Service reconfigurations
  • UTRAN mobility management
  • Inter-system procedures
  • RF design & analysis of UMTS radio networks
  • The evolution of UMTS
  • Architectures