Third Generation Mobile Networks

 

It Could Help – But Can It Work?

 

 

 

 

 

Written By: James Wright

 

Copyright © 2003 Saba Computer Consulting

 

 

Abstract

 

 

In today’s busy world of information sharing and gathering there are many new standards emerging.  These standards are that of IEEE 802.11 Wireless Network Standard, Blue Tooth, and more importantly Third Generation Mobile Networks.  These are the current relative technologies in the wireless field.  However, the bulk of this report consists of analysis, design, and implementation of the future global mobile network: 3G.

Third Generation Mobile networks are a developing standard around the world.  It does not take advantage of only one access method or topology but interweaves that of several to serve its purpose on the world market.  It was developed in kind to support the growing population of computer savvy handheld mobile communications user’s of the future. 

3G Networks will not simply jump out of the wood work.  It will of already of implemented around the world in various measures or parts of other legacy networks.  In most cases, there is an upgrade process or building block system to follow to “get to 3G”.  Looking aside from exactly how this system works, we will also delve into the reasons holding back 3G development and implementation around the world. 

In conclusion, the feasibility of this new technology is questionable by many, however that is to be answered and left up to the reader by the end of the paper.  I’ve shared my thoughts on the future of Mobile Networks based on my research.  In general, I feel a lot of money and work have gone into the research and making the “idea of the system” come to life.  The real problem, that is mistaken for feasibility, in everyone’s mind is the problems around the world with licensing, economics, and more importantly spectrum allocation.  These issues dealt with in the same vigor that brought this new standard to life will definitely guarantee the success of Third Generation Mobile Networks.                 

- James Wright

 

 

Index

 

·        Abstract

·        Part 1 – Introduction                                                       Page 1
·        Part 2 – How wireless technology has influenced our life   Page 3

 

·        Section 1 – IEEE 802.11 Wireless Network Standard.

·        Section 2 – Blue Tooth Wireless Standard

 

·        Part 4 – Evolution of Mobile Networks                            Page 21

 

·        Section 1 – 3G Requirements / Specifications

·        Section 2 – Third Generation Systems / Methods

·        Section 3 – Network Operations

·        Section 4 – 3G Network Node

·        Section 5 – Quality of Service on 3G

·        Section 6 – Security

·        Section 7 – Problems

·        Section 8 – Economics

·        Section 9 – Applications and Development

·        Section 10 – Hardware and User Terminals

·        Section 11 – Spectrum Issues

·        Section 12 – International Deployment of 3G

 

Part 1 - Introduction

 

            The future of a wireless connected world is growing more apparent each day.  With the induction of new designs, methods, and standards our lives become immensely easier.  In this year alone at least one person in ten has a mobile telephone.  That figure only grows higher and higher as technology and building blocks of previous systems become more advanced.

 

Throughout this paper, I will be mentioning the current technologies in the wireless field and more importantly, the mobile wireless field.  What has brought us to this point?  Why do we need it?  How will we benefit from it?  We will explore these answers and many more through the focused discussion of Mobile Networks.

 

The two brief technologies, which I feel are important to the history of wireless, are Blue tooth and the IEEE 802.11 Wireless network standard.  Mind you, there are plenty of other wireless technologies available, such as going in depth into radio stations, satellite communication, infrared beams, home wireless phones, and the like.  However, a line must be drawn as to what is relevant in today’s wireless world and 802.11 and Blue tooth technologies are nothing to be passed over lightly.

 

The Third Generation mobile wireless field deserves the bulk of research and understanding, since it was developed on something I like to call “building block system”.  A building block system is when we develop technologies to meet our needs at a current time and as time goes by, this system no longer meets our needs and it is then upgraded.  This is the basis for the Mobile Generation Wireless Networks that are seen throughout Europe, Asia, Japan, and the United States.

 

Third Generation Mobile networks, known as 3G, will integrate mobile voice services with high-speed data transfer.  A whole new world will and can open up with just the flip of a 3G wireless phone.  There are very important issues that play a role in this new technology, such as: System Design/Architecture, Development/Evolution of this system, Security issues, Problems with 3G, Economics, Spectrum allocation, Application development, Hardware development, and International deployment.  During the course of this paper these issues will be brought up and explained at length

 

I encourage the reader to keep an open mind as well as a fresh memory.  The technology that goes into Mobile Wireless Communications calls for a field with many acronyms and commonly used expressions.  However, aside from the technical babble of the wireless systems, I feel the reader will walk away with a sure understanding of where our world stands in the global mobile market, how the technology works, and if it will at all succeed.

 

The Future of data communications may very well be a different from copper or fiber optic – What if there were no wires at all?

 

Part 2 - How wireless technology

has influenced our life

 

            The future of wireless wasn’t built out of thin air (well maybe part of it was); it was built on previous technologies.  In today’s world it wouldn’t be too forthcoming to say you do not already have a wireless technology in your home at the moment.  If you take a moment and think through a typical day of your life you will see just how far we’ve come and where we been.  Wireless technology has been around long before the Millennium and isn’t a brand new idea.  The new ideas of today have only sprouted from what existed yesterday.  It’s more of an idea that’s been built on for years.

 

The building of this technology has greatly influenced and made our lives easier to manage.  It is this power of technology that makes our lives unique, special, and easier that really sparks my interest.

 

Here are some examples of how we currently live:

 

 

 

Many of the above listed technologies have been around for years and many fail to realize its importance on the world.  Every time we come up with a solution that involves wiring our home, telephones, or general communication needs we suddenly desire the idea to not have the wires connected anymore.  We live for it, we strive for it, and it is the next level for us.

 

Part 3 - Current Technologies for Wireless

 

            Now that I’ve introduced the basics of wireless communication, we’ll delve more in depth to what is current.  The previous stated technologies are profound indeed, but most were not developed for data transfer or computer integration.  We are a data hungry world – Information is power.  An alternative method for gaining this information and building from previous ideas has empowered us to develop some very unique systems.  As we know it, today’s world is filled with data streaming from everywhere and anywhere, and the need for fast and efficient wireless solutions is upon us. 

 

 

The three prominent technologies in my opinion are:

 

  1. IEEE 802.11 Wireless Networking Standard
  2. Blue Tooth Wireless Short wave Standard
  3. Third Generation Mobile Networks

 

The later will be explained in depth further into the paper.  At the moment we will concentrate on the 802.11 and Blue tooth standards for wireless communications.  They both are the most current and fresh technologies out of development in the field.

 

Section 1 - 802.11 Wireless Network Standard

 

            For years many of our businesses have set up vast internal networks to deal with their information processing needs.  These networks were built on various technologies such as token-ring or Ethernet.  In general, they were built using wires.  This was not only limited to building based communication but land based as well, with implementation of OC3 lines or T1 lines hard wired into major metro areas.  The fact remains that for many years now buildings have been designed, tore apart, and even built according to how wires will be distributed.  It’s a major task and could be a large hit on the pocket book.

 

Our next step was to devise a standard that did not use wires for our home or business networking needs.  This standard is called the IEEE 802.11 Wireless Network standard.  It basically allows you to install wireless cards and access points throughout your house or business, for data transfer over a network.  The speeds are comparable with that of Ethernet based networks – without the wires.  So what does this mean?  It means…

 

  1. No running CAT5 Ethernet Cable throughout a building
  2. Less time devoted to design on where to place wires
  3. Possibly a cheaper solution in the long run
  4. There may be a security risk involved as information in the air is “free”
  5. Spectrum for 2.4Ghz is not licensed therefore it may interfere with other appliances.

 

You would have to decide on these factors yourself to see whether the jump to a wireless solution is worth it, but, as a home solution where security breaches wont cost millions… it may very well be a nice alternative to ripped out the sheetrock from the walls.

 

 

How this standard came about:

 

“In 1997 the IEE adopted IEE Std. 802.11-1997, the first wireless LAN (WLAN) standard” (Intelligraphics).   This standard works in a similar fashion to that of Ethernet, just converted over to work on wireless.  According to the Orinoco staff, they believe the standard itself is a milestone in the evolution of wireless networking technology.  It will promote interoperability among products of different vendors.   Orinoco also went on further to explain how “various computing industries provided input on the 802.11 standard” (Orinoco Staff). 

 

What makes Wireless LAN unique?

 

            The Intelligraphics web source offered an interesting view on what makes wireless LANs very unique.  The fact they stated is that the 802.11 standard has to take into consideration a number of characteristics to a wireless environment.  Furthermore, there are physical characteristics of a wireless LAN such as introducing range limitations, dynamic topologies where stations move, interference, and the lack of the ability for every device to hear every other device on the wireless LAN. 

 

“These limitations force the WLAN standard to create fundamental definitions for short range LANS made up of components that are within close proximity of each other.” (Intelligraphics) 

 

Basic 802.11 Specifications:

 

The speed of this network can run to 11Mbps.  If there is interference it will drop to 5.5, then to 2Mbps and finally to 1Mbps. 

 

The range of the device is actually quite long: 1,000 feet in open areas, 250-400 in closed areas).

 

In the spectrum it uses the 2.4 GHz allocation.

 

Advantages

Disadvantages

Fast 11Mbps access

It can be expensive

Reliable system

 

Long range capabilities

Requires an access point

Easy to integrate into Ethernet

Speed sometimes fluxes

 

 

How this standard works:

 

            In general, “in a wireless network, all of the computers in your home broadcast their information to one another using radio signals” (Tyson) some wireless networks work on a peer-to-peer basis where each client can talk directly to other clients.  However, most all use something called an access point.  An access point is a wired controller that receives and transmits data to the wireless adapters installed on each computer.  In a way, this is getting rid of the wires partially, because the access point itself has to be wired into the network.

 

The Intelligraphics article goes further in depth to explain the layers of the 802.11 standard and its similarities with that of Ethernet.  This 802.11 standard addresses:

 

 

 

These standards were made available by Intelligraphics, which furthermore modeled the OSI reference model for IEEE 802.11 standard.  The architecture of 802.11 standard consists of a wireless LAN station such as a laptop of a pc and the common topologies to make the station work with others.

 

There are three common service set to deliver the 802.11 standard, they are:

 

  1. Independent Basic Service Set (IBSS)
  2. Infrastructure Basic Service Set
  3. Extended Service Set

 

Independent Basic Service Set: 1st Set

 

            This consists of only the basic set up for the 802.11 systems where each device is connected on a peer-to-peer basis without any access point.  Each mobile station communicates with the others directly, however range limitations may apply. 

 

Figure: Independent Basic Service Set

 

 

Infrastructure Basic Service Set: 2nd Set

 

            This is similar to the previous stated, however, an access point is added to connect all the stations.  “This access point provides a local relay function to the service system and all frames are relayed between stations by the access point.” (Intelligraphics).  All stations communicate with this HUB in the sky for instance and no longer communicate directly with one another.

 

This is common for distributed access systems. 

 

Figure: Infrastructure Basic Service Set

 

 

Extended Service Set: 3rd Set

 

            This is perhaps a combination of the 2nd set, but it makes availability for more than one distributed system.  It extends the mobility for a greater range through several access points.  However, one difference now is that there are more than one access points and because of that, they communicate with each other much like routers. (Intelligraphics)

 

 

Figure: Extended Service Set

 

 

Media Access Control Layer: (MAC)

 

            The MAC layer of this system provides a functionality to allow reliable data for the upper layers of the PHY media.  We will talk on the PHY layer shortly after this one.  This data delivery is based on asynchronous, best-effort, connectionless delivery of MAC layer data.  However, like in OSI architecture, there is no guarantee all the frames will deliver without errors.

 

The 802.11 MAC provides a controlled access method to the shared wireless media called Carrier-Sense Multiple Access with Collision Avoidance. (Orinoco) This is known as CSMA/CA and is very similar to that of 802.3 Ethernet LANS.

 

CSMA works on a listen before talk scheme that means the station wishing to transmit must first sense the radio channel to determine if another station is transmitting – if the medium is not busy the transmission will proceed. (Intelligraphics) 

 

Physical Layer: (PHY)

 

            The Intelligraphics Staff report on this standard explains the workings of these layers together and how the Physical layer works as well.  They explain that “the 802.11 physical layer (PHY) is the interface between the MAC and the wireless media where frames are transmitted and received.”

 

It is also mentioned that the PHY provides three functions:

 

1.      Interface to exchange frames with the upper MAC layer for transmission/reception of data.

2.      Uses signal carrier and spread spectrum modulation to transmit data frames over the media.

3.      The PHY provides a carrier sense indication back to the MAC to verify activity on the media.

 

802.11 also provides three different PHY definitions:  Frequency Hopping, Spread Spectrum, and Direct Sequence Spread Spectrum.

 

I will briefly explain Spread Spectrum and Frequency, as they are most important to know for 802.11 and terminology important for Mobile Wireless systems.

 

Spread Spectrum is a technique trading bandwidth for reliability.  What it does is use more bandwidth that the system needs in order to reduce the impact of localized interference on media.  It is something like a quality of service method where you overcompensate for what you really need just to be safe.  (Intelligraphics)

 

Frequency Hopping Spread Spectrum utilizes a set of narrow channels and hops through all of them in a predetermined sequence.  For example, the 2.3 GHz frequency band is divided into 70 channels of 1Mhz each.  Every 20 to 400 ms the system hops to another channel following an algorithm pattern.  (Severance, 2)

 

Licensing and Interoperability:

 

According to Severance whom is an Editor for the University of Michigan, it is “important for devices to cope with other unlicensed devices that might use the same or close frequency”.  For example you might consider the new 2.4 GHz wireless home phones, they may render some interoperable problems with the 802.11 standard.  Frequency hopping however will help this, but not completely get rid of the problem.

 

“A large interoperability issue is handling mobile users.  As a system moves from one base station another, some type of handoff must occur.” (Severance, 3)

 

802.11 is not using licensed parts of the spectrum so interoperability may be a problem for the future of this standard.  However, as it stands, the methods used to access this spectrum and the encoding, freq hopping, algorithms used very likely limit the instance of interference between devices. 

 

 

Conclusion on 802.11 Standard:

 

            I feel that the 802.11 technologies is a very robust and rich effort to provide wireless networking to existing Ethernet connections.  Supposedly, this standard is catching on and the benefits are being seen dramatically.  However, like any standard, one must consider if they need it, what they contend with if they have it, and just how much it will cost.

 

Section 2 – Blue Tooth Wireless Standard

 

“Blue tooth is a global de facto standard for wireless connectivity. Based on a low-cost, short-range radio link, Blue tooth cuts the cords that used to tie up digital devices.” (Nokia)

 

Nokia further goes on to explain that when two Blue tooth equipped devices come within 10 meters range of each other, they can establish a connection together. Because Blue tooth utilizes a radio-based link, it doesn't require a line-of-sight connection in order to communicate. Your laptop could send information to a printer in the next room, or your microwave could send a message to your mobile phone telling you that your meal is ready.

 

“In the future, Blue tooth is likely to be standard in tens of millions of mobile phones, PCs, laptops and a whole range of other electronic devices. As a result, the market is going to demand new innovative applications, value-added services, end-to-end solutions and much more. The possibilities opened up really are limitless, and because the radio frequency used is globally available, Blue tooth can offer fast and secure access to wireless connectivity all over the world. With potential like that, it's no wonder that Blue tooth is set to become the fastest adopted technology in history.” (Nokia)

 

However, this may sound like another 802.11 standard it is not.  You must remember that Blue tooth is a short wave system and does not require access points.  For instance, you will be able to connect devices like your laptop and your cell phone without a wire to connect to the Internet.  In a way, I feel this is a good replacement for infrared communication, in the fact that infrared is very unreliable. 

 

Consider this as a cross between the 802.11 standard and infrared communications.  “The art of connecting things is becoming more and more complex every day.  Oftentimes we feel as if we need a PH.D in electrical engineering just to set up the electronics in our house.  Blue tooth is wireless and automatic, and has a number of interesting features that should simplify our daily lives!” (Brain)

 

 

Basic Blue Tooth Specs:

 

The speed of this is 10 times slower than that of 802.11 standards. 

The range of the device is:  30 feet.

(Above stats from MSBC Staff,  Nov 15th  2001)

The Spectrum it uses is: 2.45Ghz and licensed. (Brain)

 

How Blue Tooth works:

 

Blue tooth provides agreement on a physical level.  It is a radio frequency standard.  Blue tooth is intended to get around the problems of infrared and cable synching problems.  Hardware developers such as Siemens, Intel, Toshiba, Motorola, and Ericsson develop a specification for a very small radio module to be built into computer, telephone, and entertainment equipment.

 

When a Blue tooth device comes in range with another device, an electronic conversation takes place on whether they have data to share or not.  The users do not have to press a button; it is something like a Plug and Play system.  Imagine, no more programming your universal remote to your VCR, DVD player, or TV?  Blue tooth does that having the conversation on its own. Leave it up to Blue tooth technology to communicate with other devices in your home and office.  Blue tooth uses the 2.45 radio frequency and it was set aside by ISM (International Scientific and medical devices). 

 

 

 

Picture: from Marshall Brain, Blue tooth Wireless

 

 

Blue tooth also uses frequency hopping very similar to that of 802.11 standard.  However, one way they avoid interference by sending out weak signals of 1 mill watt. Also, the low power limit and range of these devices also decrease the chance of interference vs. that of an 802.11 standard. 

 

Three important features of Blue tooth is:

 

  1. It’s wireless – When traveling, no worry for carrying any wires at all.
  2. It’s inexpensive – It should only add about $15 dollars to the price of a Blue tooth enabled device.
  3. Its easy to use – Nothing has to be done. No set ups.

 

Conclusion on Blue tooth Standard:

 

            A day in the life of having Blue tooth devices can be quite promising I believe.  Although the MSNBC staff feels that it may not become as popular as the 802.11 standard, it is still being built into many new products. 

 

You can look forward to printing documents from a handheld, cordless cell phone headsets, a universally “universal” Blue tooth remote, etc.  At the price of $2.50 per chip (MSBC Staff) installed in certain appliances, it’s near possible to remove the wires from just about any device that requires short wave data communication.

 

 

 

 

 

 

Part 4 – Evolution of Mobile Networks

 

 

            Before we dive into the workings and wonders of Third Generation Mobile networks, we need to learn how they became “Third Generation”.  Before third there was second and first, and each built upon the other.  The most built upon will be the move from 2G to 3G as it involves data and digital voice streaming.

 

Third Generation technology may seem complicated however the effect it will have on our lives is unimaginable.  You will have access to one device that will service as a camera, video camera, computer, stereo, and radio right at your fingertips.  It will most likely work anywhere in the world that there is a wireless network up to the 3G standards. 

 

According to Ericsson, a leading wireless company, “sophisticated 3G technology will soon be a reality with fast, intelligent, and affordable devices opening up betters ways of organizing your life and staying in touch”.  They also go on further to explain that this technology will offer the convenience of a digital phone with a permanent Internet connection with the speed of up to 2 Mbps for sending information from business data to video and games for kids.

 

 

The evolution road to 3G is a consists of:

 

 

 

First Generation Mobile Networks:

 

            The first generation mobile networks were developed in the 1970’s and were analog cellular systems that were a hybrid of analog voice channels and digital control channels.  The analog voice channels typically used FM and the digital control channels used simple frequency shift keying modulation.  (Harte, 11) 

 

This system was around for a while however two components made improvements on it in the 1970’s – Invention of the microprocessor and control link between mobile phone and cell site.

 

 

The problems with the analog cell network was that the digital signaling rates were limited and the transmission of complex analog voice signals limit the ability of analog systems to offer advanced authentication techniques and voice services.  “Most 1G analog phones only have processing capability of about 500,000 instructions per second.  This compared to the processing power of a 2G digital phone is enormous.  2G phones offer 10 million to 40 million instructions per second (MIPS). (Harte, 12)  In general, over time, it suddenly became not as effective with the induction of new hardware and software systems.  It is because of this lack of speed and MIPS that the analog systems became old and could not use advanced security features like encryption.

 

Second Generation Mobile networks:

 

            Second generation networks came leaps ahead of analog.  These systems were developed in the 1980’s and used digital radio channels for both voice (digital voice) and digital control channels.  2G systems used more efficient modulation technologies.  

 

These modulation technologies are as such:

 

 

These new systems digitized everything unlike that of the analog systems.  “The new system provided better quality and higher capacity at a lower cost” (Secretary General ITU) Being that the system was digital now, the radio channels could offer a universal data transmission system which divided into many logical channels that performed different services.  Some were used for control purposes and others for data transmission.

 

“Second generation systems use multiple access technologies to allow more customers to share individual radio channels or use narrow channels to allow more radio channels into a limited amount of radio spectrum band.

 

There are three different access technologies in 2G systems:

 

 

“These technologies reduce the Radio Frequency channel, share a radio channel by assigning users to brief time slots, or divide a wide RF channel into many different coded channels.” (Harte, 13)

 

Now that this system is digital it was more common to use data communication channels.  New features like short messaging system (SMS) and web browsing became more apparent in 2G terminal phones.  It even goes as far as having software on a phone and any updates it needs, it is automatically sent from the communications carrier.  For example, you have a cell phone and an online address book you update with your computer – it is possible to keep this phone book updated on your phone as well.

 

            2G systems picked up where 1G left off.  It improved authentication and voice privacy capabilities.  This of course made cell phones easier to use, faster, and greatly reduced cellular fraud and security breaches.

 

2.5 Generation Mobile Networks: (Enhanced Digital Cellular)

 

            As of 2001 this is currently where most of the worlds cellular market lies.  This was not a full step but more of an upgrade on existing 2G networks and standards.  2.5G is more prevalent anywhere other than the United States.  It was developed because there was a need for higher speed data transmission, efficient packet data transmission, and more efficient radio channel capacity through the use of new modulation technology.

 

High Speed Circuit Switched Data was developed specifically for this standard to overcome the limited maximum user data transfer rate of 9.6Kbps in the original GSM system from 2G.  Now, upgrading the 2G systems with a HSCSD you are able to transfer data at a rate of 64kbps.  This is a little faster than a typical home modem, but still a great improvement to that of the 2G systems.  A HSCSD involves upgrading the network software and adding gateways that allow connection to data networks (such as the internet).

 

Now, as part of this 2.5, two new access methods were developed:

 

  1. GPRS – General packet radio service
  2. EDGE – Enhanced Data Rates for Global evolution

 

 

1 - GPRS provided was a very popular method that provided high-speed packet data service on a GSM network and is commonly used in Europe.  (Secretary General ITU)  This system dynamically assigned time slots on the GSM radio channels to allow quick and efficient transfer of small packets of data.  Furthermore, GPRS allows point to point and point to multipoint packet data transmission. 

 

The maximum data transmission capacity using GPRS method is 171.2kbps.  That is roughly three times as fast as that of typical home modems (56k).  However, to provide this GPRS service equipment is needed and added to the network.  These items are such like GPRS support node and a GPRS backbone network.  The support node called SGSN is similar to that of a mobile switching station (later explained).

Example of the GPRS system  (Harte, 15)

 

2- EDGE was an evolved system of the GSM radio channel that used a new modulation and packet transmission to provide advanced high speed data services  (Ericsson).  EDGE is actually, according to Ericsson, something very close to that of 3G network for rural areas, leaving the newest technology (3G) for more urban areas.  They believe it to be more cost efficient that way.

 

The EDGE system can run up to speeds of 384kbps almost leaving GPRS in the dust and doubling it.  EDGE does however have some issues.  For example, EDGE reuses frequencies in nearby cells making the interference level for each time slot higher than normal.  This interference can be acceptable if it leaves out some data packets, but not important messages such as handshaking and control.  EDGE is an overlay on the GSM method so “as customers convert from the other system and radio channels become lightly loaded, more of those radio channels can be removed and additional EDGE channels can be added – allowing for gradual conversion from one technology to another being GSM/EDGE.

 

Third Generation Mobile Networks: (Explained as the focus of this paper)

 

Fourth Generation Mobile Networks *: “It is expected that Fourth Generation (4G) networks will be developed around the year 2010” (Secretary General ITU)

 

Conclusion:

 

            As you can see, the generations leading up to 3G are quite strong on building upon each other.  Even the move to 3G itself will build upon the back of previous technologies and generations.  Below is an evolution chart provided by Ericsson:


Part 5 – Third Generation Mobile Networks

 

            “The collective third generation technologies are often referred to as 3G services.  IMT-2000 is the global body that co-ordinate the global standard and spectrum allocation for 3G services through the World Radio Congress.” (AllNetDevices Staff, June 30th, 2000)  3G is also commonly called UMTS (Universal Mobile Telecommunication System).  ITU identified specific frequency bands for the third generation network in 1992.  “UMTS is a part of the International Telecommunications Unions IMT-200 vision of a global family of third generation mobile communication systems” (GSMWorld)

 

Wireless vendors such as AT&T, British TeleComm, Ericsson, Lucent, Nokia, etc formed an alliance called 3G.IP or 3GPP, which is a 3G global partnership.  They will “focus on developing technology around the WCDMA and EDGE broadband air interfaces.  These radio access techniques determine how a signal is sent from the handheld device to the base and how efficient operators use the radio spectrum.” (AllNetDevices Staff, June 10th, 1999)  Furthermore, ITU also supports multiple wireless standards that will adhere to the overall ITU layout. 

 

“The volume of data traffic is increasing rapidly and is expected to pass volume of voice in 2001” (Garber IEEE, 8) Furthermore, more and more people are buying data services and it’s becoming a larger market.  With this comes the demand for an increased bandwidth for wireless networks.

 

Section 1 – 3G Requirements / Specifications:

 

            Within the 3G technologies there are several channels within one connection so users can access telephone services, the web, chat, video, etc all on one connection. It is meant for multitasking and computers and the requirements were developed around these needs.  3G was a planned standard for mobile users to be used around the world by 2002, however, in light of recent events only Japan has entered this realm – others are testing it.

 

Speeds:

 

Fast Moving (In a car)

144 Kbps

Slow Moving (Walking)

384Kbps

Fixed Location (Standing or Site)

2.05Mbps

 

 

Multi system compatibility is also needed for 3G to work.  It should allow customers to roam globally (on different frequency bands) and be able to hand off to a 2nd generation system being backwards compatible.  It should be possible for 2nd generation service providers to upgrade their system to 3G and connect the systems together if they must as well as be efficient.

 

These new standards would allow workers to use wireless technology for email, file transfers, e-commerce, and web access.

 

 

Section 2 - Third Generation Systems / Methods:

 

            These wireless systems will combine cellular, wireless office telephone systems, cordless telephone systems, and advanced intelligent features into one portable device.  (Harte, 23)  Currently, there are three different popular system specifications for 3rd Generation:

 

  1. WCDMA – Wideband code division multiple access
  2. TD/CDMA – Time division code division multiple access
  3. CDMA2000

 

WCDMA, according to Harte, uses a wide radio frequency channel, efficient coding, and multiple channels to provide for both low speed circuit and high-speed packet services.  It uses a direct sequence code division multiple access technology.  Multiple physical channels exist on the same frequency band by using different spreading codes.  The spreading code is used to create several chips per bit of information.  These codes are chosen to be non-interfering with each other. 

 

TD/CDMA is a process that allows communication between two devices by time-sharing.  It uses time division duplex technology where, device 1 transmits and device 2 listens for a short period of time.  After the transmission finish, the devices then reverse their roles and the process continues repeatedly.  Physically, it appears as if data is flowing in both directions at the same time, but it isn’t.

 

 

CDMA2000 is an evolved version of the 2nd generation IS-95 CDMA system.  This system combines multiple IS-95 radio channels with enhanced transmission protocols to provide for advanced high-speed data services. 

 

CMDA in general is based on spread spectrum technology.  It is highly suitable for encrypted transmissions and has a long career in military usage.  “CDMA increases spectrum capacity by allowing all users to occupy all channels at the same time.  Transmissions are spread over the whole radio band, and each voice or data call is assigned a unique code to differentiate from the other calls carried over the same spectrum.  CDMA allows for a “soft hand off”, which means that terminals can communicate with several base stations at the same time.  The dominant radio interface for third generation mobile, or IMT 200, will be a wideband version of CDMA” (Secretary General ITU)

 

 

Section 3 – Network Operations:

 

3G technologies improve current digital mobile networks.  It removes an overhang from the analog networks where connections are circuit switched.  Instead, 3G will use packet switching that is a common technique that is used on the Internet.  “Each packet is efficiently dispatched and reassembled into a seamless voice call or message at the other end, thanks to unique identification codes attached to each packet of data and the processing power of the latest mobile and computing devices.” (Ericsson, Oct 22 2001)

 

Key elements that exist in 3G are that it includes better packet data control, high-speed data transmission, multiple radio channel bandwidths, and multiple channel data rates.  Data transmission can go up to 2Mbps as stated earlier and the radio channel bandwidths can be from narrow 2G and wide 3G.  The multiple channel data rates means that if your radio channel quality is good you will have a higher data transmission rate.

 

Basic Cell Operation:

 

1.      When your mobile device is turned on, it initializes itself by scanning a predetermined set of control channels and then tuning into the strongest one. 

2.      After it initializes, it enters the idle mode where it waits to be paged for an incoming call.

3.      When a call comes in or out, the cell device enters system access mode to try to access the system via a control channel.

4.      It gains access to the control channel then sends a voice channel designation message indicating an open voice channel.

5.      The mobile device then tunes to the voice channel and enters conversation mode.

6.      As the device operates it uses frequency modulation, speech encoding, frequency hopping, and packet data transmission.