Evolution of Mobile Communication
This is a brief review of how the evolution of the mobile technology occurred with the time....
Evolution of Mobile Communication
Evolution of Mobile Communication 1. Introduction Communication is a vital factor which allows people to connect with each other around the world. From the very early ages, people thought of having communication methods to connect with the rest of the world. Early people used symbolic formations, sounds to express their feelings to others & eventually they started to speak. Then with the advancement of communication, the languages were formed as formal communicating methods & people understood the importance of communicating with the rest of the world. So they started to move forward in communication & thus various techniques were found. From paper based media to electronic media like telephone, television, radio, the communication was developed rapidly during the last century. As they are wired media, the use is limited to certain perimeter & soon people found that it is a great limitation in communication. So people did so many experiments to have a wireless communication, to overcome the limitations of the wired communication media. As a result of that, the mobile communication was found to make the communication more efficient & effective. 2. 1st Generation Mobile Communication (1G) 1G or 1st generation mobile phones were the earliest cellular systems that were developed in early 80’s. The idea was come up with the development of the short ranged radio telephones. At early 70’s, the short ranged radio waved telephones were developed such as walkie-talkies. These systems were used to communicate over small geographical area & the system is fully analog. Which means communication is done by switching from sender to receiver. In these telephone systems, the communication was done by transmitting radio signals on specific frequencies through the airwaves. In the early 80’s, the 1st generation phones were developed to increase the efficiency of the mobile technology. 1G phone are also analogue & the major improvement done was increasing the range of the transmission. So that the communication can be done over a large area, than the walkie-talkies. 1st Generation mobile phones used a single universal network standard known as Advanced Mobile Phone Systems (AMPS). In this technology, separate frequencies were used for each conversation & therefore needed considerable bandwidth for a large number of users. That means the bandwidth needed to be increased with the users. In AMPS, the cell centers could assign channels to handsets based on the signal strength. It also allowed re-using the same frequency in various locations without interference. This allowed a large number of phones to be supported over a geographical area. AMPS cellular service was operated in the 800-900 MHz cellular FM band.
2.1 Features of 1G Mobile Technology
Mobility – can take the cellular where needed
Circuit switched technology.
Basic voice calls only.
Limited local & regional coverage.
Phones were large in size.
2.1.1 Inventor of 1G
2.1.2 1G mobile phone
mobile-Dr Martin Cooper
3. 2nd Generation Mobile Technology (2G) After the 1st Generation mobile technology, at early 90’s, the 2G or 2 nd Generation mobile networks were established. It was developed as a solution for problems arose in analogue systems. Therefore digital encryption of the voice calls was used in 2G technology. That means the digital mobile communication started with the 2 nd Generation. 2G cellular telecom networks were commercially launched on GSM (Global Systems for Mobile Communication) standard in Finland in 1991. Along with the digital advancement, 2G came with another two benefits, over the 1G mobile phones. 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels & also introduced the data services for mobile phones. The ability to send text messages or SMS (Short Message Service) was 1 st invented in 2G mobile phones. Thus this SMS facility made the mobile communication more efficient & effective to use. 2G technologies can be divided into two standards depending on the type of multiplexing used. TDMA-based (Time Division Multiple Access) & CDMA-based (Code Division Multiple Access) are those two standards. The phrase multiple access means that more than one user can utilize each call. TDMA assigns each call a certain portion of time on a designated frequency. TDMA is used for Interim Standard 54 (IS-54) & Interim Standard 136 (IS-136).in TDMA each conversation gets the radio for one-third of the time & therefore TDMA has three times the capacity of an analog system using the same number of channels. TDMA operates in 800 MHz (IS-54) or 1900 MHz (IS-136). CDMA gives a unique code to each call & spreads it over the available frequencies. After digitizing data, spreads it over the entire available bandwidth. CDMA is the basis for Interim Standard 95 (IS-95) & operates both in 800 MHz & 1900 MHz bands. The main 2G standards are as follows.
GSM- TDMA based technology
Cdmaone –CDMA based technology
PDC – TDMA based used exclusively in Japan 3.0
2G mobile phones
There are number of advantages in 2G technology. Introducing the digital data services such as SMS & email is a major improvement. The lower power emission made sure the health safety. With analogue systems, same phone number can be in two or more phones & it was eliminated in 2G. The privacy is ensured in 2G phones than the 1G phone. 3.1 2.5G Mobile Technology 2.5G is the 2nd Generation enhanced version of 2G technology. The enhancement achieved through implementing a packet switched domain in addition to circuit switched domain. This is to give user a better services & access to the internet. 2.5G gives higher data rates & additional capabilities. The technology used to access internet is General Packet Radio Service (GPRS). GPRS can provide data rates from 56 kb/s, up to 115 kb/s. GPRS can be used for services such as Wireless Application Protocol (WAP) access, Multimedia Messaging Service (MMS), & for internet services such as email & World Wide Web (WWW) access. 3.2 2.75G Mobile Technology Another enhancement in 2G technology is the 2.75G & it is the road to the 3G technology. GPRS networks evolved in Enhanced Data Rates for GSM Evolution (EDGE). EDGE, Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC) is a backward compatible digital mobile phone technology & it allows improved data transfer rates. EDGE is developed in 2003 by AT&T in US. EDGE is standardized by 3GPP & it provides increased capacity of GSM/GPRS networks. Higher data rates are achieved by switching to more sophisticated methods of coding with existing GSM timeslots.
4. 3rd Generation Mobile Generation (3G) 3rd Generation or the 3G mobile technology is the latest state in the development of wireless communication technology. The 3G technology was first used in Japan in 2001, as they did not use the 2.5G technology; thus they needed a solution to bridge the gap & face the capacity requests. Since then it improved a lot by adding many sophisticated features for the users. 3G uses a host of high tech infrastructure networks, handsets, base stations, switches & other devices to allow mobile to offer high speed internet access, data & CD quality services. Currently, over 80% of the world population is using this 3G mobile technology for their communication purposes. Compared to earlier mobile phones, 3G handsets provide many new features like TV streaming, multimedia, videoconferencing, web browsing, e-mail, paging, fax, navigational maps & etc. Also the ability to enhance the features & add additional functionalities to the available applications is another added advantage in this 3G technology. 3G technologies are developed according to the International Telecommunications Union’s IMT-2000 specification. Universal Mobile Telephone System (UMTS) is one of the technologies used in 3G
mobiles which are based on W-CDMA technology. This is used in the countries which used GSM technology & UMTS is managed by the 3GPP organization. Another standard is the CDMA2000 which is an enhancement of earlier version of 2G CDMA standard (IS-95) & is managed by 3GPP2. The other standard is TD-CDMA which is being developed in China. The 3G technology allows 2Mbps speed for stationary & 384Kbps for mobile systems.
4.0 3G mobile phones
4.1 3.5G mobile Technology 3.5G is the next generation in mobile technology which is also called High-Speed Downlink Packet Access (HSDPA). It is a mobile telephony protocol & is a packet-based data service in W-CDMA, downlink with a data transmission up to 8-10 Mbit/s over a 5 MHz bandwidth. HSDPA is enabled with a new transport layer channel which is called High Speed Downlink Shared Channel (HS-DSCH) to send packets on the downlink. It includes 3 layers to enhance its services. HS-SCCH, HS-PDSCH & HS-DPCCH are those three layers. In HSDPA or 3.5G technology, the data is transmitted together with error correction bits, thus can be corrected without re-transmission. The HS-DSCH channel is shared between users using channel-dependant scheduling to make the best use of available radio conditions. So the packet scheduling in 3.5G phones, is very faster than other technologies. Adaptive modulation & coding is another significant improvement in 3.5G technology. As well as improving data rates, it also decreases latency & so the round trip time for applications also reduced.
3.5G mobile phones
5. 4th Generation Mobile Technology (4G) 4G can be considered as the future of the mobile technology. With the rapid development in the technology, people try to have more sophisticated & advanced mobile communication. With the high rates of requirements, 4G technology comes into the play. Even though 3G is a successful invention, still there are many reasons to go for 4G technology, as listed below.
High input fees for the 3G service licenses.
Difference in license terms
3G phones are expensive
Lack of coverage
Wider bandwidths, higher bit rates
Scalability of mobile networks
In 4G mobile phones, the data transfer rate is more than 100 Mbit/s & link efficiency of 15 bit/s/Hz in the downlink & 6.75 bit/s/Hz in uplink. It expected to have high quality services for multimedia purposes such as real time audio, high speed data, HDTV video content, mobile TV, etc. As the future expectations from a mobile phone is more towards the internet access, in 4G technology, data communication is via IPV6 technology to support for the rapid growing users. It uses multi standard wireless systems such as Bluetooth, WI-Fi. The CDMA technology is not used in 4G instead uses the Orthogonal Frequency Division Multiplexing (OFDM) technology. OFDM allows transferring data more than other forms of multiplexing. It simplifies the design of the transmitter & receiver & allows using almost the entire frequency band. WiMax connection is using the 4G technology in the mobile phones recently. A 4G mobile phone can be considered as a fully functional computer with the portability.
4G Mobile phones
6. Summary With the development of technology, the wireless communication developed very rapidly from 1G to 4G. Still people do researches regarding the mobile communication to provide a sophisticated & reliable efficient communication for the end users. 7. References Figure 2.1.1- http://www.devicedaily.com/cell-phones/the-history-of-mobile-phones.html Figure 2.1.2 - http://1day-at-a-time.blogspot.com/2007/04/nokia-phones-1g-2g-3g.html Figure 3.0 - http://student.dcu.ie/~ahmeda3/assign2/start2.html Figure 4.0 - http://www.mobilephonereviews.org/apple/apple-iphone-3g-mobile-phone/ http://www.mobilephonereviews.org/nokia/nokia-5320-xpressmusic-3g-mobile-phone/ http://ieeemacau.eee.umac.mo/ieee_student/history%20of%20mobile%20phone.htm