Mobile phone technology is attached in our everyday life. Mobile phone has given us the independence to communicate between each other regardless of place, city and country and the backbone of this is mobile phone technology. A mobile phone is owned by three among four people in this world. This growth of mobile technology is tremendous.
There are many technologies in use in mobile communication. Those are like GSM(Global System for Mobile Communication),CDMA(Code Division Multiple Access),EDGE(Enhanced Data Rate For GSM Evolution) to UMTS(Universal Mobile Telecommunication System) or W-CDMA(Wide Band Code Division Multiple Access) and CDMAOne(IS-95) to CDMA 2000 1X,EV-DV and Mobile TV technologies such as Media FLO,DMB and DVB-H.
GSM (Global System for Mobile Communication) is the most widely used mobile communication technology in the world. This technology gives us the advantage to use the mobile communication service all over the world through roaming. One of its advantage to make it become popular is interoperatibility.
The letters originally was the abbreviation of the words Groupe Speciale Mobile, but as it becomes popular enormously, the meaning of the words also change radically and now it stands for Global system for Mobile communications. The GSM technology was first used in the year 1991 and it is increasing rapidly for some of its unique advantage. Now the total number of GSM subscriber in the world is around 3 billion and this number is increasing steadily.
GSM System overview:
GSM technology is the 2G(second generation ) mobile communication technology. The aim was to serve a large number of subscriber and increasing the channel capacity and giving the advantage of interoperatibility which was not there in the analog system (first generation system) earlier.GSM achieved this by using a multiplexing technique which is called as TDMA(Time Division Multiple Access).By adopting this it was possible to accommodate a large number of user in a limited bandwidth by increasing the channel capacity. In additional to this ciphering was added to encrypt the voice in the communication medium. The previous system was not that much secured and anyone was able to trace the voice data through a receiver.
GSM basic services:
Voice communication s the basic service that GSM provides. To provide this service in GSM the voice data is first encoded and then decoded by a vocoder device. As the voice service is the basic service in GSM,in addition to this GSM system also provides other services. Though their quality is that much keen like the 3G service still those are popular where the 3G service is still not available.GSM supports data rate up to 9.6 kbps,teletext and voice text and other value added services.
A service that provided by GSM which is enormously popular and availed by the people of every category is short message service(SMS).Earlier this was developed only for GSM but after that other mobile technologies also adopted this and this is successfully used in all technologies. This service has become popular in all mobile phone services, particularly young people likes this because the cost is low and this service provides alphanumeric messaging, forwarding, bidirectional messaging etc.
GSM Technology Basics:
GSM technology uses 200 KHZ RF frequency channels. In this technology each carrier is divided into eight carriers to give access to eight users in a carrier. This is called time division multiplexing.So,this is why it is called a TDMA (Time Division Multiple Access) system.
The BTS(Base Transreceiver Station) are located in a small groups’ BSC(Base Switching Centre) controls a group of base transreceiver station, a MSC(Mobile Switching Center) controls all these BSC’s. Attached with this is two other devices HLR(Home Location Register) and VLR(Visitor Location Register) which tracks the location of the mobile.
The evolution of GSM is EDGE. Implementing EDGE data can be transferred up to a speed of 384kbps.In some cases it is also called as EGPRS(Enhanced General Packet Radio Service System).This system can be called as 2.5G system.GSM uses Gaussian Minimum Shift Keying for data transfer but EDGE uses the 8 PSK which increase the data rate significantly.
GSM EDGE Basics:
GSM EDGE cellular technology is an update to the existing GSM network technology. This can be implemented in the existing GSM network by installing software.
CDMA1X2000 is the up gradation of the original IS-95 cdma one system.CDMA has a number of evolution for which CDMA1X2000 is the first one.
The aim of this CDMA1X200 is to provide a migration path from the original cdma one which is existing.This format is the basic 3G standard.
The first change that was made in CDMA1X200 was in the Walsh Code which was initially 64 bits in cdmaone and now it is being changed to 128 bits. Another code name turbo code was introduced in this technology to detect the error more efficiently.
In Cdmaone a form of QPSK was used where the data in both I and Q channel was same but in CDMA1X2000 the data in Q and I channel is different .So, half of the bandwidth can be used for same number of chips or in other words double number of chips can be sent through the same bandwidth.
So, the CDMA1XX2000 has provided an efficient spectral efficiency and also improves the performance and the data rate is significantly high.
3G HSPA or High Speed Packet Access:
The technology 3G HSPA or High Speed Packet Access is a technology which is a combination of two technologies, one is the uplink and one is the downlink which can be built on to the existing 3G-UMTS or W-CDMA technology to provide increased data transfer speeds in data transmission.
16 QAM is used in the downlink to increase the data rate.Here,sharing the channels provide a great efficiency and also integrates with IP and packet data concepts.
3G LTE or 3G LONG TERM EVOLUTION:
To compete the high data rate services like WiMax,the work on next generation of cellular technology is already been started and also implemented in some cases.
The third generation partnership project that works on the development of theUMTS 3G started their evolutionary work with a workshop that was held in Toronto ,Canada on November,2004.
The target of LTE is to get the download speed up to 100Mbps and upload speed of 50Mbps in each 20Mhz spectrum.LTE is also required to serve 200 active users in each 5MHz cell.
The basic work of 3G LTE is already been done by 3GPP and the infrastructure upgrading task is also going on parallel.
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One of the most successful inventions in 20th century is the mobile phone which is also called as cellular phone. Now-a-days mobile phone becomes the most popular communication device. According to International Telecommunication Union (ITU) there were total 5.3 billion mobile subscribers up to the end of 2010.This figure shows clearly the success of the mobile phone industries. Though in the early age of mobile phones the facility of mobile phones were limited only between voice to voice communication but now -a- days this is not limited only to voice to voice communication. Today we have mobile handsets with camera, multimedia video messaging and 3G handsets. The use of WAP and GPRS( General Packet Radio Service) have made some radical changes in the society. Now using this technologies we can control the share market,e-mailing,bank payment and can get the latest news.
If we research the history we will get the below time line in the history of mobile phone:
In 1934 the Federal Communication Commission of United States begun managing the radio spectrum.It was their decision who will get what spectrum for mobile communication. This commission gave priority to the emergency services like government companies, utility services etc.
In 1946 a mobile telephone services (MTS) was introduced by AT&T which is a company from united states. At that time if a mobile user wanted to make a radio call then he or she needs to search for a 15 Mega-Hertz or 35 Mega-Hertz radio band before they could place a successful call. Using this procedure only one person was able to talk at a time and the direction of the call was controlled by one push-to-talk button just like a walkie talkie. The first mobile phone was weighted 76lbs (34 kg) When mobile phones were first launched at that time subscribers were only able to call national calls but were not able to call overseas. To call overseas they need to connect via a landline.
In the early stage of 1980 AT&T took help from the consultant company McKinsey & Co. to forecast the growth of mobile market until the end of the year 2000.They projected a world market of 900000 approximately.
In 1982 AT&T’s proposal for AMPS( Advanced Mobile Phone System) was approved by the FCC which was submitted on 1971.FCC allocated the frequency from 824-894 Mega Hertz band.From 1982-1990 AMPS was the analog service. After that digital AMPS came online on 1990.
In the month of May 1983 Callnet and Vodafone got the license to provide the cellular phone service in the UK.
In 1985 Callnet and Vodafone started their business commercially. The installation charge was comparatively high. The installation charge was about 120£ and the connection charge was 60£. At that time the mobile sets were around 20 kg weighted. For this reason this mobile phones were mostly used in the cars.
On 1st July,1991 the first GSM (Global System for Mobile Communication) call was made from a commercial service. Harri Holkeri, governor of the Bank of Finland, was the person who telephoned the mayor of Helsinki to talk about the price of Baltic herring.
In the year 1993 during the month of September the first GSM 1800 Mega Hertz band was introduced in the world.
In 1994 the British company Hutchison Microtel announced the launch of “Orange” in its UK network. At this time SMS (Short Message Service) was also introduced with normal voice call.
1998 was the year in which mobile phones were more sold than cars and PC’s.
From 1st January ,1999 Mobile phone users were able to view the older numbers on which they called earlier.UK was the first country to provide the service to the customers. In this year during the month of March the mobile users in UK were also able to send e-mails and got the facility to use the web on mobile phones.
First generation Cellular phones:
In 1983 Motorola first bring the world the truly portable mobile phone. The model of that mobile phone was Motorola DynaTAC 8000X.Federal Communication Commission (FCC) approved this to use only in United States. After 15 years of research and after spending about 100 million dollars in research work this mobile hand set finally came into the market for true use. The DynaTAC8000X was really light weighted for its time and only weighted 28 ounces. The size was like 13 inches x 1.75 inches x 3.5 inches and was known as the brick of its shape. Dr. Martin Cooper of Motorola took a great part to make this handset.
Second generation Cellular phones:
Cell phones from the early 1990’s are considered to be the second generation cellular phones and these phones were able to operate under the system such as GSM(Global System for Mobile Communication) ,IS-136 (TDMA) and IS-95 CDMA(Code Division Multiple Access).Phone based on second generation technology were much smaller than the brick phones in first generation. This all were operated under digital network which were available in 1990 in United States. The second generation networks were online most of the time and this network has fast signaling and lower call drop rates. The weight of second generation mobile handsets were 100-200 grams. They were truly portable without the help of a large and weighted battery.
Third Generation Cellular Phones:
Now-a-days we use third generation cellular phones. This is commonly referred to as 3G.Third generation cell phones arrived just short after the second generation hand sets came to market. The cause is mainly the due to the many innovations in the technology and services. Standards for third generation is different depending on the existing network. In third generation handsets this is possible to receive two megabits of maximum data rate in indoors and 384 kbits for outdoor use.Third generation handsets also has the facility such as streaming radio and TV,as well as WiFi.
From the early stages of mobile phone from today’s 3G phone, the mobile phone technology highly developed in the last 20 years. Depending on the mobile handset services other high tech companies are also developing other services like OS(operating system).Symbian is like that kind of operating system.
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