Mobile Technology
First generation:-
1G analog system for mobile communications saw two key improvements during the 1970s: the invention of the microprocessor and the digitization of the control link between the mobilephone and the cell site. AMPS ( Advance mobile phone system ) was first launched by US which is 1G mobile system. It is best on FDMA technology which allows users to make voice calls within one country.
Second generation:-
2G digital cellular systems were first developed at the end of the 1980s. These systems digitized not only the control link but also the voice signal. The new system provided better quality and higher capacity at lower cost to consumers. GSM (Global system for mobile communication) was the first commercially operated digital cellular system which is based on TDMA.
Third generation:-
3G systems promise faster communications services, including voice, fax and Internet, anytime and anywhere with seamless global roaming. ITU’s IMT-2000 global standard for 3G has opened the way to enabling innovative applications and services (e.g. multimedia entertainment, infotainment and location-based services, among others). The first 3G network was deployed in Japan in 2001. 2.5G networks, such as GPRS (Global Packet Radio Service) are already available in some parts of Europe.
3G technology supports 144 Kbps bandwidth, with high speed movement (e.g. vehicles), 384 Kbps (e.g. on campus) & 2 Mbps for stationary (e.g.inbuilding )
Fourth generation:-
At present the download speed for mode data is limited to 9.6 kbit/sec which is about 6 times slower than an ISDN (Integrated services digital network) fixed line connection. Recently, with 504i handsets the download data rate was increased 3-fold to 28.8kbps. However, in actual use the data rates are usually slower, especially in crowded areas, or when the network is "congested". For third generation mobile (3G, FOMA) data rates are 384 kbps (download) maximum, typically around 200kbps, and 64kbps upload since spring 2001. Fourth generation (4G) mobile communications will have higher data transmission rates than 3G. 4G mobile data transmission rates are planned to be up to 20 megabits per second.
Before understanding 4G, we must know what is 3G ? 3G initiative came from device manufactures, not from operators. In 1996 the development was initiated by Nippon Telephone & Telegraph (NTT) and Ericsson; in 1997 the Telecommunications Industry Association (TIA) in the USA chose CDMA as a technology for 3G; in 1998 the European Telecommunications Standards Institute (ETSI) did the same thing; and finally, in 1998 wideband CDMA (W-CDMA) and cdma2000 were adopted for the Universal Mobile Telecommunications System (UMTS).
W-CDMA and CDMA 2000 are two major proposals for 3G. In this CDMA the information bearing signal is multiplied with another faster ate, wider bandwidth digital signal that may carry a unique orthogonal code. W-CDMA uses dedicated time division multiplexing (TDM) whereby channel estimation information is collected from another signal stream. CDMA 2000 uses common code division multiplexing (CDM) whereby channel estimation information can be collected with the signal stream.
Access Technologies (FDMA, TDMA, CDMA) -
FDMA: Frequency Division Multiple Access (FDMA) is the most common analog system. It is a technique whereby spectrum is divided up into frequencies and then assigned to users. With FDMA, only one subscriber at any given time is assigned to a channel. The channel therefore is closed to other conversations until the initial call is finished, or until it is handed-off to a different channel. A "full-duplex" FDMA transmission requires two channels, one for transmitting and the other for receiving. FDMA has been used for first generation analog systems.
TDMA: Time Division Multiple Access (TDMA) improves spectrum capacity by splitting each frequency into time slots. TDMA allows each user to access the entire radio frequency channel for the short period of a call. Other users share this same frequency channel at different time slots. The base station continually switches from user to user on the channel. TDMA is the dominant technology for the second generation mobile cellular networks.
CDMA: Code Division Multiple Access is based on "spread" spectrum technology. Since it is suitable for encrypted transmissions, it has long been used for military purposes. 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 are 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.
Beyond 3G
In the field of mobile communication services, the 4G mobile services are the advanced version of the 3G mobile communication services. The 4G mobile communication services are expected to provide broadband, large capacity, high speed data transmission, providing users with high quality color video images, 3D graphic animation games, audio services in 5.1 channels. We have been researching the vision of 4G mobile communication systems, services, and architectures. We also have been developing the terminal protocol technology for high capacity, high speed packet services, public software platform technology that enables downloading application programs, multimode radio access platform technology, and high quality media coding technology over mobile networks.
Reasons To Have 4G -
1.Support interactive multimedia services: teleconferencing, wireless Internet, etc.
2.Wider bandwidths, higher bit rates.
3.Global mobility and service portability.
4.Low cost.
5.Scalability of mobile networks.
1G analog system for mobile communications saw two key improvements during the 1970s: the invention of the microprocessor and the digitization of the control link between the mobilephone and the cell site. AMPS ( Advance mobile phone system ) was first launched by US which is 1G mobile system. It is best on FDMA technology which allows users to make voice calls within one country.
Second generation:-
2G digital cellular systems were first developed at the end of the 1980s. These systems digitized not only the control link but also the voice signal. The new system provided better quality and higher capacity at lower cost to consumers. GSM (Global system for mobile communication) was the first commercially operated digital cellular system which is based on TDMA.
Third generation:-
3G systems promise faster communications services, including voice, fax and Internet, anytime and anywhere with seamless global roaming. ITU’s IMT-2000 global standard for 3G has opened the way to enabling innovative applications and services (e.g. multimedia entertainment, infotainment and location-based services, among others). The first 3G network was deployed in Japan in 2001. 2.5G networks, such as GPRS (Global Packet Radio Service) are already available in some parts of Europe.
3G technology supports 144 Kbps bandwidth, with high speed movement (e.g. vehicles), 384 Kbps (e.g. on campus) & 2 Mbps for stationary (e.g.inbuilding )
Fourth generation:-
At present the download speed for mode data is limited to 9.6 kbit/sec which is about 6 times slower than an ISDN (Integrated services digital network) fixed line connection. Recently, with 504i handsets the download data rate was increased 3-fold to 28.8kbps. However, in actual use the data rates are usually slower, especially in crowded areas, or when the network is "congested". For third generation mobile (3G, FOMA) data rates are 384 kbps (download) maximum, typically around 200kbps, and 64kbps upload since spring 2001. Fourth generation (4G) mobile communications will have higher data transmission rates than 3G. 4G mobile data transmission rates are planned to be up to 20 megabits per second.
Before understanding 4G, we must know what is 3G ? 3G initiative came from device manufactures, not from operators. In 1996 the development was initiated by Nippon Telephone & Telegraph (NTT) and Ericsson; in 1997 the Telecommunications Industry Association (TIA) in the USA chose CDMA as a technology for 3G; in 1998 the European Telecommunications Standards Institute (ETSI) did the same thing; and finally, in 1998 wideband CDMA (W-CDMA) and cdma2000 were adopted for the Universal Mobile Telecommunications System (UMTS).
W-CDMA and CDMA 2000 are two major proposals for 3G. In this CDMA the information bearing signal is multiplied with another faster ate, wider bandwidth digital signal that may carry a unique orthogonal code. W-CDMA uses dedicated time division multiplexing (TDM) whereby channel estimation information is collected from another signal stream. CDMA 2000 uses common code division multiplexing (CDM) whereby channel estimation information can be collected with the signal stream.
Access Technologies (FDMA, TDMA, CDMA) -
FDMA: Frequency Division Multiple Access (FDMA) is the most common analog system. It is a technique whereby spectrum is divided up into frequencies and then assigned to users. With FDMA, only one subscriber at any given time is assigned to a channel. The channel therefore is closed to other conversations until the initial call is finished, or until it is handed-off to a different channel. A "full-duplex" FDMA transmission requires two channels, one for transmitting and the other for receiving. FDMA has been used for first generation analog systems.
TDMA: Time Division Multiple Access (TDMA) improves spectrum capacity by splitting each frequency into time slots. TDMA allows each user to access the entire radio frequency channel for the short period of a call. Other users share this same frequency channel at different time slots. The base station continually switches from user to user on the channel. TDMA is the dominant technology for the second generation mobile cellular networks.
CDMA: Code Division Multiple Access is based on "spread" spectrum technology. Since it is suitable for encrypted transmissions, it has long been used for military purposes. 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 are 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.
Beyond 3G
In the field of mobile communication services, the 4G mobile services are the advanced version of the 3G mobile communication services. The 4G mobile communication services are expected to provide broadband, large capacity, high speed data transmission, providing users with high quality color video images, 3D graphic animation games, audio services in 5.1 channels. We have been researching the vision of 4G mobile communication systems, services, and architectures. We also have been developing the terminal protocol technology for high capacity, high speed packet services, public software platform technology that enables downloading application programs, multimode radio access platform technology, and high quality media coding technology over mobile networks.
Reasons To Have 4G -
1.Support interactive multimedia services: teleconferencing, wireless Internet, etc.
2.Wider bandwidths, higher bit rates.
3.Global mobility and service portability.
4.Low cost.
5.Scalability of mobile networks.
