3G- WIRELESS TECHNOLOGY

INTRODUCTION

The first generation of mobile phones consisted of the analog models that emerged in the early 1980s. The second generation of digital mobile phones appeared about ten years later along with the first digital mobile networks. During the second generation, the mobile telecommunications industry experienced exponential growth both in terms of subscribers as well as new types of value-added services. Mobile phones are rapidly becoming the preferred means of personal communication, creating the world's largest consumer electronics industry.Third Generation (3G) mobile devices and services will transform wireless communications in to on-line, real-time connectivity. 3G wireless technology will allow an individual to have immediate access to location-specific services that offer information on demand.


EVOLUTION OF 3G

A complete evolution to 3G wireless technology is mandated by the end of 2000 in Japan and by the end of 2001 in Europe. The first pre-commercial 3G network was launched by
NTT DOCOMO in Japan in May 2001. The first commercial launch of 3G was also by NTT DoCoMo in Japan on 1 October 2001, although it was initially somewhat limited in scope, broader availability was delayed by apparent concerns over reliability. In January 2002 SK Telecom (Telecom Company in South Korea ) launched second commercial network .

The first European pre-commercial network was at the Isle of Man by British Telecom, and the first commercial network in Europe was opened for business by Telnor in December 2001 with no commercial handsets and thus no paying customers.The first commercial United States 3G network was by Monet Mobile Networks, but this network provider later shut down operations. The second 3G network operator in the USA was Verizon Wireless in October 2003 In December 2007, 190 3G networks were operating in 40 countries, according to the Global Mobile Suppliers Association (GSA).

In 2008, India entered into 3G Mobile arena with the launch of 3G enabled Mobile and Data services by BSNL in Bihar([Patna]). BSNL is the first Mobile operator in India to launch 3G services. After that ([MTNL]) launched [3G] in Mumbai & Delhi. Government owned Bharat Sanchar Nigam Ltd has already been provided with a 3G license and has been operating its services in 380 cities by the end of March 2010. Nation wide auction of 3G wireless spectrum in April 2010 has been announced, and 3G services by private service providers are expected by the September 2010.

The implementation of 3G wireless systems raises several critical issues, such as the successful backward compatibility to air interfaces as well as to deployed infrastructures. Compatibility and interworking between the new 3G wireless systems and the old legacy networks must be achieved in order to ensure the acceptance of new 3G wireless technology by service providers and end-users.




FIRST GENERATION WIRELESS TECHNOLOGY

The first generation of wireless mobile communications was based on analog signalling. Analog systems, implemented in North America, were known as Analog Mobile Phone Systems (AMPS), while systems implemented in Europe and the rest of the world were typically identified as a variation of Total Access Communication Systems (TACS). Analog systems were primarily based on circuit-switched technology and designed for voice, not data.


SECOND GENERATION WIRELESS TCHNOLOGY


The second generation (2G) of the wireless mobile network was based on low-band digital data signalling. The most popular 2G wireless technology is known as Global Systems for Mobile Communications (GSM). GSM systems, first implemented in 1991, are now operating in about 140 countries and territories around the world. An estimated 248 million users now operate over GSM systems. GSM technology is a combination of Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA). The first GSM systems used a 25MHz frequency spectrum in the 900MHz band.
In addition to GSM, a similar technology, called Personal Digital Communications (PDC), using TDMA-based technology, emerged in Japan. Since then, several other TDMA-based systems have been deployed worldwide and serve an estimated 89 million people worldwide. While GSM technology was developed in Europe, Code Division Multiple Access (CDMA) technology was developed in North America. CDMA uses spread spectrum technology to break up speech into small, digitized segments and encodes them to identify each call. CDMA systems have been implemented worldwide in about 30 countries and serve an estimated 44 million subscribers. While GSM and other TDMA-based systems have become the dominant 2G wireless technologies, CDMA technology is recognized as providing clearer voice quality with less background noise, fewer dropped calls, enhanced security, greater reliability and greater network capacity. The Second Generation (2G) wireless networks mentioned above are also mostly based on circuit-switched technology. 2G wireless networks are digital and expand the range of applications to more advanced voice services, such as Called Line Identification. 2G wireless technology can handle some data capabilities such as fax and short message service at the data rate of up to 9.6 kbps, but it is not suitable for web browsing and multimedia applications.



2G+ WIRELESS NETWORKS

The virtual explosion of Internet usage has had a tremendous impact on the demand for advanced wireless data communication services. However, the effective data rate of 2G circuit-switched wireless systems is relatively slow -- too slow for today's Internet. As a result, GSM, PDC and other TDMA-based mobile system providers and carriers have developed 2G+ technology that is packet-based and increases the data communication speeds to as high as 384kbps.
2G+ systems are based on the following technologies: High Speed Circuit-Switched Data (HSCSD), General Packet Radio Service (GPRS) and Enhanced Data Rates for Global Evolution (EDGE) technologies.
HSCSD - HSCSD is one step towards 3G wideband mobile data networks. This circuit-switched technology improves the data rates up to 57.6kbps by introducing 14.4 kbps data coding and by aggregating 4 radio channels timeslots of 14.4 kbps.

GPRS- GPRS is an intermediate step designed to allow the GSM world to implement a full range of Internet services without waiting for the deployment of full-scale 3G wireless systems. GPRS technology is packet-based and designed to work in parallel with the 2G GSM, PDC and TDMA systems that are used for voice communications and for table look-up to obtain GPRS user profiles in the Location Register databases. GPRS uses a multiple of the 1 to 8 radio channel timeslots in the 200kHz-frequency band allocated for a carrier frequency to enable data speeds of up to 115kbps. The data is packetized and transported over Public Land Mobile Networks (PLMN) using an IP backbone so that mobile users can access services on the Internet, such as SMTP/POP-based e-mail, ftp and HTTP-based Web services.

EDGE- EDGE technology is a standard that has been specified to enhance the throughput per timeslot for both HSCSD and GPRS. The enhancement of HSCSD is called ECSD, whereas the enhancement of GPRS is called EGPRS. In ECSD, the maximum data rate will not increase from 64 kbps due to the restrictions in the A interface, but the data rate per timeslot will triple. Similarly, in EGPRS, the data rate per timeslot will triple and the peak throughput, including all eight timeslots in the radio interface, will exceed 384 kbps.



THIRD GENERATION WIRELESS TECHNOLOGY


3G wireless technology represents the convergence of various 2G wireless telecommunications systems into a single global system that includes both terrestrial and satellite components. One of the most important aspects of 3G wireless technology is its ability to unify existing cellular standards, such as CDMA, GSM, and TDMA, under one umbrella. The following three air interface modes accomplish this result: wideband CDMA, CDMA2000 and the Universal Wireless Communication (UWC-136) interfaces.

Wideband CDMA (W-CDMA) is compatible with the current 2G GSM networks prevalent in Europe and parts of Asia. W-CDMA will require bandwidth of between 5Mhz and 10 Mhz, making it a suitable platform for higher capacity applications. It can be overlaid onto existing GSM, TDMA (IS-36) and IS95 networks. Subscribers are likely to access 3G wireless services initially via dual band terminal devices. W-CDMA networks will be used for high-capacity applications and 2G digital wireless systems will be used for voice calls.

CDMA2000 is backward compatible with the second generation CDMA IS-95 standard predominantly used in US.

The third radio interface, Universal Wireless Communications – UWC-136, also called IS-136HS, was proposed by the TIA and designed to comply with ANSI-136, the North American TDMA standard.


3G wireless networks consist of a Radio Access Network (RAN) and a core network. The core network consists of a packet-switched domain, which includes 3G SGSNs and GSNs, which provide the same functionality that they provide in a GPRS system, and a circuit-switched domain, which includes 3G MSC for switching of voice calls. Charging for services and access is done through the Charging Gateway Function (CGF), which is also part of the core network. RAN functionality is independent from the core network functionality. The access network provides a core network technology independent access for mobile terminals to different types of core networks and network services.


PROTOCOL LAYERS IN 3G INFRASTRUCTURE

Global Mobility Management (GMM): protocol that includes attach, detach, security, and routing area update functionality.

Node B Application Part (NBAP): provides procedures for paging distribution, broadcast system information and management of dedicated and logical resources.

Packet Data Convergence Protocol (PDCP): maps higher level characteristics onto the characteristics of the underlying radio-interface protocols.PDCP also provides protocol transparency for higher layer protocols.

Radio Link Control (RLC): provides a logical link control over the radio interface.


Medium Access Control (MAC): controls the access signaling (request and grant) procedures for the radio channel.

Radio resource Control (RRC): manages the allocation and maintenance of radio communication paths.

Radio Access Network Application Protocol (RANAP): encapsulates higher layer signaling. Manages the signaling and GTP connections between RNC and 3G-SGSN, and signaling and circuit-switched connections between RNC and 3G MSC.

Radio Network Service Application Part (RNSAP): provides the communication between RNCs.

GPRS Tunnel Protocol (GTP): protocol that tunnels the protocol data units through the IP backbone by adding routing information. GTP operates on top of TCP/UDP over IP.

Mobile Application Part (MAP): supports signaling between SGSN/GGSN and HLR/AuC/EIR.

AAL2 Signaling (Q.2630.1, Q.2150.1, Q.2150.2, AAL2 SSSAR, and AAL2 CPS): protocols suite used to transfer voice over ATM backbone using ATM adaptation layer 2.

Sigtran (SCTP, M3UA): protocols suite used to transfer SCN signaling protocols over IP network.






FEATURES OF 3G


Data rates: 3G technology can provide a minimum data rate of 2 Mbit/s for stationary or walking users, and 384 kbit/s in a moving vehicle

Security: 3G networks offer greater security than their 2G predecessors. By allowing the UE (User Equipment) to authenticate the network it is attaching to, the user can be sure the network is the intended one and not an impersonator.
In addition to the 3G network infrastructure security, end-to-end security is offered when application frameworks such as IMS are accessed, although this is not strictly a 3G property.





APPLICATIONS

The bandwidth and location information available to 3G devices gives rise to applications not previously available to mobile phone users. Some of the applications are:

• Mobile TV – a provider redirects a TV channel directly to the subscriber's phone where it can be watched.
• Video on demand – a provider sends a movie to the subscriber's phone.
• Video conferencing – subscribers can see as well as talk to each other.
• Tele-medicine – a medical provider monitors or provides advice to the potentially isolated subscriber.
• Location-based services – a provider sends localized weather or traffic conditions to the phone, or the phone allows the subscriber to find nearby businesses or friends.

REFERENCES

NATIONALWIDE WIRELESS.NET
SLIMSOUISSI.ADVANCES RESEARCH.NOVATTEL WIRELESS INC.
CDMA DEVELOPMENT GROUP.WHITE PAPERS
GOOGLE
ANSWERS.COM
SCRIBD.COM