Seminar Topics & Project Ideas On Computer Science Electronics Electrical Mechanical Engineering Civil MBA Medicine Nursing Science Physics Mathematics Chemistry ppt pdf doc presentation downloads and Abstract

3G Technology Overview

[attachment=30864]

Major 3G Players

International Telecommunications Union (ITU) defined International Mobile Telecommunications-2000 (IMT-2000) as the
umbrella of third generation (3G) wireless (not just cellular mobile) communications technologies. This initiative envisioned
a single 3G system that integrates a variety of systems including cellular mobile, cordless phone, wireless data and LEO
satellite systems. The following table gives the current members of IMT-2000 initiative

There are some other players too:

· 3G America (formerly, Universal Wireless Communications Consortium or UWCC) (http://www.3gamerica)

The mission of 3G Americas is to promote and facilitate the seamless deployment throughout the Americas of GSM and
its evolution to 3G and beyond. The organization provides a unified voice for operators, vendors and content providers
promoting the growth and success of GSM wireless technologies via GSM, GPRS, EDGE, UMTS-HSPA and LTE.
· Open Mobile Alliance (OMA) http://www.openmobilealliance
"The mission of the Open Mobile Alliance is to facilitate global user adoption of mobile data services by specifying
market driven mobile service enablers that ensure service interoperability across devices, geographies, service providers,
operators, and networks while allowing businesses to compete through innovation and differentiation."
The OMA was created in June 2002 as an answer to the proliferation of industry forums each dealing with a few
application protocols: the WAP Forum (focused on browsing and device provisioning protocols), the Wireless Village
(focused on instant messaging and presence), the The SyncML Initiative (focused on data synchronization), the Location
Interoperability Forum, the Mobile Games Interoperability Forum and the Mobile Wireless Internet Forum. Each of
these forums had its bylaws, its decision-taking procedures, its release schedules, and in some instances there was some
overlap in the specifications, causing duplication of work. The OMA was created to gather these initiatives under a
single umbrella.

3G Technology


[attachment=33968]

Here is a simple introduction to some aspects of 3G radio transmission technologies (RTTs). You will find the subjects covered in this section useful if you later consider the more detailed discussions in the sections on 3G Standards and 3G Spectrum.
Simplex vs. Duplex
When people use walkie-talkie radios to communicate, only one person can talk at a time (the person doing the talking has to press a button). This is because walkie-talkie radios only use one communication frequency - a form of communication known as simplex

TDD vs. FDD

Wireless duplexing has been traditionally implemented by dedicating two separate frequency bands: one band for the uplink and one band for the downlink (this arrangement of frequency bands is called paired spectrum). This technique is called Frequency Division Duplex, or FDD. The two bands are separated by a "guard band" which provides isolation of the two signals

Symmetric Transmission vs. Asymmetric Transmission

Data transmission is symmetric if the data in the downlink and the data in the uplink is transmitted at the same data rate. This will probably be the case for voice transmission - the same amount of data is sent both ways. However, for internet connections or broadcast data (e.g., streaming video), it is likely that more data will be sent from the server to the mobile device (the downlink).
FDD transmission is not so well suited for asymmetric applications as it uses equal frequency bands for the uplink and the downlink (a waste of valuable spectrum). On the other hand, TDD does not have this fixed structure, and its flexible bandwidth allocation is well-suited to asymmetric applications, e.g., the internet (see this PDF file for more details). For example, TDD can be configured to provide 384kbps for the downlink (the direction of the major data transfer), and 64kbps for the uplink (where the traffic largely comprises requests for information and acknowledgements). See this PDF file for more details.

TDMA vs. CDMA

We have considered how a mobile phone can send and receive calls at the same time (via an uplink and a downlink). Now we will examine how many users can be multiplexed into the same channel (i.e., share the channel) without getting interference from other users, a capability called multiple access. For 3G technology, there are basically two competing technologies to achieve multiple access
TDMA and CDMA:
TDMA is Time Division Multiple Access. It works by dividing a single radio frequency into many small time slots. Each caller is assigned a specific time slot for transmission. Again, because of the rapid switching, each caller has the impression of having exclusive use of the channel.
CDMA is Code Division Multiple Access. CDMA works by giving each user a unique code. The signals from all the users can then be spread over a wide frequency band. The transmitting frequency for any one user is not fixed but is allowed to vary within the limits of the band. The receiver has knowledge of the sender's unique code, and is therefore able to extract the correct signal no matter what the frequency.
This technique of spreading a signal over a wide frequency band is known as spread spectrum. The advantage of spread spectrum is that it is resistant to interference - if a source of interference blocks one frequency, the signal can still get through on another frequency. Spread spectrum signals are therefore difficult to jam, and it is not surprising that this technology was developed for military uses.
Finally, let's consider another robust technology originally developed by the military which is finding application with 3G: packet switching.

Circuit Switching vs. Packet Switching

Traditional connections for voice communications require a physical path connecting the users at the two ends of the line, and that path stays open until the conversation ends. This method of connecting a transmitter and receiver by giving them exclusive access to a direct connection is called circuit switching.

3G Standards

The dream of 3G is to unify the world's mobile computing devices through a single, worldwide radio transmission standard. Imagine being able to go anywhere in the world secure in the knowledge that your mobile phone is compatible with the local system, a scenario known as "global roaming". Unfortunately, the process of unifying the numerous international standards has proved to be extremely difficult. After difficult negotiation, a 3G "standard" called IMT-2000 emerged as a rather unsatisfactory compromise. IMT-2000, in fact, represents several incompatible standards lumped together under one banner. The hope of IMT-2000 is that phones using these different standards will be able to move seamlessly between all networks, thus providing global roaming.
The rather fragmented nature of IMT-2000 has resulted in a proliferation of confusion acronyms (e.g., TDMA, UMTS, EDGE) often referred to as "alphabet soup". Possibly the most important acronym to remember is "UMTS": this is the 3G standard for Europe and Japan.
UMTS is the successor to the current ultra-successful GSM mobile phone standard in Europe. UMTS is being very heavily sold as the 3G standard (some sources use the terms "3G" and "UMTS" synonymously, though this is really not correct and just adds to the confusion).