30-05-2012, 01:31 PM
4G TECHNOLOGY
[attachment=23522]
ABSTRACT:
Telecommunications was the most discussed subject of the past decade. From Wi-Fi to Wimax, and from cell phones to smart phones, the sky is the limit for heated debates. For the layman too, things have changed remarkably over the last two decades. There are now diverse media for communication and the rate of phone calls have dropped drastically. With generations of telecom networks behind us, it’s time to turn the corner and see where we stand today and the shape of things seven years from now.
INTRODUCTION:
The first generation of wireless telecommunication systems, back in the 1970’s, had more than ten analogue standards established worldwide.
The first generation systems had a low capacity and hit the saturation level soon This forced the development of second generation (2G) systems in 1980’s,which took two directions: while the global system for mobile communication(GSM)was chosen by Europe and the US, Japan and Korea adopted the Code-Division Multiple Access (CDMA)technology.
The main aim is to provide global connectivity from person to person, from person to machine and from machine to machine.
THE FIRST GENERATION:
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.
First generation phones of mobile communication brought a revolution in wirelessed network The design of 1G phones first started in 1970 and was implemented at 1984.the features of 1G are:
These were based on the analogue system.
Introduction of this new type of wireless phones was a quantum leap in mobile communication, especially in terms of capacity and mobility.
The prominent ones among 1Gsystem are Advanced Mobile Phone System (AMPS), Nordic Mobile Telephone (NMT) and Total Access Communication Systems(TACS).
They were of analogue voice, synchronous data up to 9.6kbps.
Its core network is of PSTN.
FAILURES OF 1G COMMUNICATION:
1G technology has failed to provide
They transmit only analogue voice transformation.
Their coverage area is very much small.
They contain mono service only, i.e. they can communicate one person with any one person only.
SMS’s cannot be done.
Their radio frequency is very small of 400-800MHz.
Band width is of very small such as 2.4-30kbps.
They use telecom network which are of very small use.
THE SECOND GENERATION:
To overcome the difficulties of 1st generation second generation concept was introduced.
The following are the most popular 2G standards:
Global System Mobile (GMS).
Interim Standard-136(IS-136), also known as North American Digital Cellular (NADC).
It used digital modulation for improved audio quality.
It include Digital –AMPS (D-AMPS), Code Division Multiple Access (CDMA) and Personal Digital Communication (PDC).
Different standards serve different applications with different levels of mobility, capability and service area.
This 2Gnetwork links all the cells together into a single network.
The standard service include circuit -switched voice, fax, and data as well as voice mail and it’s notification.
FAILURES OF 2G COMMUNICATION:
Even though 2G provides much more facilities than 1G and provides more comfort, its failures can be explained as
More standards are used in the limits of country or to a restricted area, and are in compatible.
Speech transmission still dominates the airways.
The driven technique circuit switching is not efficient for communication with multi-user.
The coverage area is medium.
Core networks are just telecom networks as in the previous generation.
It has a data band width of 14.4kbps.
THE 2.5 GENERATION:
The 2.5 G technologies have evolved to overcome the failures of 2G communication which has the technologies such as:
High speed circuit switched data (HSCSD).
Enhanced data rates for GSM (EDGE).
Its circuit is packet switched; working on the basis of e-mails it sends text and graphics, rich data packets at very fast speed.
Transmission control protocol (TCP) provided a virtual extended connection for reliability.
The main protocols such as HTTP web servers, SMTP for e-mail, and SNTP for network management.
It extends its range from CDMA to Time Division Multiple Access (TDMA).
FAILURES OF 2.5G:
Even after some inventional changes are made from 2G, there are still questions in front of us as:
Still the speed is very low.
They used telecom networks as in the last two generations.
Coverage area also doesn’t increased which remained as medium area.
THE THIRD GENERATION:
While 2G systems such as GSM, IS-95, and CDMA one were designed to carry speech and low-bitrate data, 3G systems are being designed solely to provide high-data rate services. This generation of wireless communications attempt to converge various 2G and 2.5Gnetworks into a single uniform system. The 2G telecom networks include both terrestrial and satellite components. The outstanding features of 3G can be given by:
They add multimedia facilities to 2.5G phones by allowing video, audio and graphics applications.
The idea behind 3Gis to have a single network standard.
3G cellular services known as universal mobile telecommunication system (UMTS) will sustain higher data rates and opened the door to many internet style applications.
UMTS increases transmission speed to 2Mbps per mobile user and establishes a global roaming standard.
It will support both packet-switched and circuit-switched data transmission.
Users gain access through a combination of terrestrial wireless and satellite transmission.
The higher band width of UMTS promises video conferencing and virtual home environment.
FAILURES OF 3G COMMUNICATION:
Failures of 3G can be given by :
Difficulty in continuously increasing bandwidth and high data rate to meet multimedia service requirements, together with the coexistence of of different services, needing different QO’s and bandwidth.
Limitations of spectrum and it’s allocation.
Difficult to roam across distinct service environments in different frequency bands.
Lack of end- to-end seamless transport mechanism spanning a mobile sub network and a fixed one.
THE FOURTH GENERATION:
People began to talk about 4G , pretty well before 3G got it’s fullest possible application.4G being developed to provide data transfer speeds up to 50 times more than of 3G. This is expected to be available in the market by 2010.
History of fourth generation:
The original cellular phone network in the United States was called the Analog Mobile Phone System (AMPS). It was developed by AT&T and launched in 1983. AMPS operated in the 800 MHz range, from 824-849 MHz and 869-894 MHz. The lower band was used for transmissions from the phone to the base station, and the upper band was for the reverse direction (Leon-Garcia and Widjaja 2000). This allows full duplex conversation, which is desirable for voice communications. The bands were divided into 832 subchannels, and each connection required a pair: one each for sending and receiving data. Each subchannel was 30 KHz wide, which yielded voice quality comparable to wired telephones. The subchannels were set up so that every subchannel pair was exactly 45 MHz apart (Leon-Garcia and Widja ja 2000). Several of the channels were reserved exclusively for connection setup and
teardown. The base station in a particular cell kept a record of which voice subchannel pairs were in use. Though usable, this system included a number of security aws. Because each phone
transmitted (like any radio transmitter) in the clear on its own frequency, the phones in this system “were almost comically vulnerable to security attacks” (Riezenman 2000, 40). The
crime of service theft plagued cellular service providers, as individuals with radio scanners could “sni ” the cellular frequencies and obtain the phone identification numbers necessary
to “clone” a phone (Riezenman 2000, 39). The abuser could then use this cloned phone to make free telephone calls that would be charged to the legitimate user’s account. In an attempt to stem these attacks, service providers worked with Congress to punish such abuse. Congress passed a law in 1998 to make owning a cellular scanner with intent to defraud a federal crime (Riezenman 2000, 40). Unfortunately, punitive legislation was not enough to
solve the problem; a new standard was needed. To create a new standard, engineers needed to start a new, examining each part of the current system.
[attachment=23522]
ABSTRACT:
Telecommunications was the most discussed subject of the past decade. From Wi-Fi to Wimax, and from cell phones to smart phones, the sky is the limit for heated debates. For the layman too, things have changed remarkably over the last two decades. There are now diverse media for communication and the rate of phone calls have dropped drastically. With generations of telecom networks behind us, it’s time to turn the corner and see where we stand today and the shape of things seven years from now.
INTRODUCTION:
The first generation of wireless telecommunication systems, back in the 1970’s, had more than ten analogue standards established worldwide.
The first generation systems had a low capacity and hit the saturation level soon This forced the development of second generation (2G) systems in 1980’s,which took two directions: while the global system for mobile communication(GSM)was chosen by Europe and the US, Japan and Korea adopted the Code-Division Multiple Access (CDMA)technology.
The main aim is to provide global connectivity from person to person, from person to machine and from machine to machine.
THE FIRST GENERATION:
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.
First generation phones of mobile communication brought a revolution in wirelessed network The design of 1G phones first started in 1970 and was implemented at 1984.the features of 1G are:
These were based on the analogue system.
Introduction of this new type of wireless phones was a quantum leap in mobile communication, especially in terms of capacity and mobility.
The prominent ones among 1Gsystem are Advanced Mobile Phone System (AMPS), Nordic Mobile Telephone (NMT) and Total Access Communication Systems(TACS).
They were of analogue voice, synchronous data up to 9.6kbps.
Its core network is of PSTN.
FAILURES OF 1G COMMUNICATION:
1G technology has failed to provide
They transmit only analogue voice transformation.
Their coverage area is very much small.
They contain mono service only, i.e. they can communicate one person with any one person only.
SMS’s cannot be done.
Their radio frequency is very small of 400-800MHz.
Band width is of very small such as 2.4-30kbps.
They use telecom network which are of very small use.
THE SECOND GENERATION:
To overcome the difficulties of 1st generation second generation concept was introduced.
The following are the most popular 2G standards:
Global System Mobile (GMS).
Interim Standard-136(IS-136), also known as North American Digital Cellular (NADC).
It used digital modulation for improved audio quality.
It include Digital –AMPS (D-AMPS), Code Division Multiple Access (CDMA) and Personal Digital Communication (PDC).
Different standards serve different applications with different levels of mobility, capability and service area.
This 2Gnetwork links all the cells together into a single network.
The standard service include circuit -switched voice, fax, and data as well as voice mail and it’s notification.
FAILURES OF 2G COMMUNICATION:
Even though 2G provides much more facilities than 1G and provides more comfort, its failures can be explained as
More standards are used in the limits of country or to a restricted area, and are in compatible.
Speech transmission still dominates the airways.
The driven technique circuit switching is not efficient for communication with multi-user.
The coverage area is medium.
Core networks are just telecom networks as in the previous generation.
It has a data band width of 14.4kbps.
THE 2.5 GENERATION:
The 2.5 G technologies have evolved to overcome the failures of 2G communication which has the technologies such as:
High speed circuit switched data (HSCSD).
Enhanced data rates for GSM (EDGE).
Its circuit is packet switched; working on the basis of e-mails it sends text and graphics, rich data packets at very fast speed.
Transmission control protocol (TCP) provided a virtual extended connection for reliability.
The main protocols such as HTTP web servers, SMTP for e-mail, and SNTP for network management.
It extends its range from CDMA to Time Division Multiple Access (TDMA).
FAILURES OF 2.5G:
Even after some inventional changes are made from 2G, there are still questions in front of us as:
Still the speed is very low.
They used telecom networks as in the last two generations.
Coverage area also doesn’t increased which remained as medium area.
THE THIRD GENERATION:
While 2G systems such as GSM, IS-95, and CDMA one were designed to carry speech and low-bitrate data, 3G systems are being designed solely to provide high-data rate services. This generation of wireless communications attempt to converge various 2G and 2.5Gnetworks into a single uniform system. The 2G telecom networks include both terrestrial and satellite components. The outstanding features of 3G can be given by:
They add multimedia facilities to 2.5G phones by allowing video, audio and graphics applications.
The idea behind 3Gis to have a single network standard.
3G cellular services known as universal mobile telecommunication system (UMTS) will sustain higher data rates and opened the door to many internet style applications.
UMTS increases transmission speed to 2Mbps per mobile user and establishes a global roaming standard.
It will support both packet-switched and circuit-switched data transmission.
Users gain access through a combination of terrestrial wireless and satellite transmission.
The higher band width of UMTS promises video conferencing and virtual home environment.
FAILURES OF 3G COMMUNICATION:
Failures of 3G can be given by :
Difficulty in continuously increasing bandwidth and high data rate to meet multimedia service requirements, together with the coexistence of of different services, needing different QO’s and bandwidth.
Limitations of spectrum and it’s allocation.
Difficult to roam across distinct service environments in different frequency bands.
Lack of end- to-end seamless transport mechanism spanning a mobile sub network and a fixed one.
THE FOURTH GENERATION:
People began to talk about 4G , pretty well before 3G got it’s fullest possible application.4G being developed to provide data transfer speeds up to 50 times more than of 3G. This is expected to be available in the market by 2010.
History of fourth generation:
The original cellular phone network in the United States was called the Analog Mobile Phone System (AMPS). It was developed by AT&T and launched in 1983. AMPS operated in the 800 MHz range, from 824-849 MHz and 869-894 MHz. The lower band was used for transmissions from the phone to the base station, and the upper band was for the reverse direction (Leon-Garcia and Widjaja 2000). This allows full duplex conversation, which is desirable for voice communications. The bands were divided into 832 subchannels, and each connection required a pair: one each for sending and receiving data. Each subchannel was 30 KHz wide, which yielded voice quality comparable to wired telephones. The subchannels were set up so that every subchannel pair was exactly 45 MHz apart (Leon-Garcia and Widja ja 2000). Several of the channels were reserved exclusively for connection setup and
teardown. The base station in a particular cell kept a record of which voice subchannel pairs were in use. Though usable, this system included a number of security aws. Because each phone
transmitted (like any radio transmitter) in the clear on its own frequency, the phones in this system “were almost comically vulnerable to security attacks” (Riezenman 2000, 40). The
crime of service theft plagued cellular service providers, as individuals with radio scanners could “sni ” the cellular frequencies and obtain the phone identification numbers necessary
to “clone” a phone (Riezenman 2000, 39). The abuser could then use this cloned phone to make free telephone calls that would be charged to the legitimate user’s account. In an attempt to stem these attacks, service providers worked with Congress to punish such abuse. Congress passed a law in 1998 to make owning a cellular scanner with intent to defraud a federal crime (Riezenman 2000, 40). Unfortunately, punitive legislation was not enough to
solve the problem; a new standard was needed. To create a new standard, engineers needed to start a new, examining each part of the current system.