Long Term Evolution (LTE) is the latest high speed 4G technology introduced in 2010 by AT & This standard is developed by 3GPP and is specified in its release 8 series. Its architecture is based on Internet Protocol (IP) packet switched network. It is mainly used for data. There are many procedures to make a voice call:
2) Circuit switched fallback (Fallback to circuit switched domain at calling time)
3) Simultaneous voice and LTE (simultaneously changes in circuit switched mode at calling time and LTE mode providing data services)
LTE is the best technology from 1G, 2G and 3G.First generation (1G) introduced in 1980 was based on analog technology. In it, signal is modulated to higher frequency, approximately 150 MHz and up. Its speed is so less.
To overcome the drawback of 1G, 2G came into picture in 1991 based on digital technique.2G technologies can be divided into TDMA (Time Division Multiple Access) based and CDMA (Code Division Multiple Access) based depending upon the type of multiplexing used. The main 2G standards are GSM, IS-95, PDC, D-AMPS and IS-136.The main disadvantage was that some digital signals may be weaker enough to reach the cell tower. Its data rate is less.
To increase its speed, 2.5G i.e. GPRS (General Packet Radio Service) came into existence. It has packet switched domain with circuit switched domain. It provides data rate of 56 kbps to 115 kbps. It can be used for services like WAP(Wireless Application Protocol),MMS(Multimedia Messaging Service) and internet communication services like email, www access etc. GPRS data transfer is charged in megabyte of traffic transferred while data communication via circuit switching is billed per minute of connection time whether the user is utilizing it or in idle state.
To increase the capacity, 2.75G i.e. EDGE (Enhanced Data Rate for GSM Evolution) came into picture. In it, 8PSK encoding is used. It has maximum 250 kbps speed.
After 2.75G, the technology moved to 3G. It was introduced in 2000.It offers faster data transmission speeds, greater network capacity and more advanced network services. Using 3G, we get the minimum speed of 2mbps for stationary mobile and 384 kbps for moving. It is known as “Mobile Broadband Technology” because using it; we can get the divergent data transfer rate. It uses packet switching for data transmission. It uses turbo codes for error correction.3G technologies are CDMA2000, UMTS etc. The frequency band used in 3G is 1.5-2.8 GHz. In it, peak upload rate is 5 Mbps and download rate is 100 Mbps. In it, video conferencing and other high quality services can be used. But wider bandwidth was not available in it.
Now data transmission is becoming more and more popular than voice calls. After 3G, 4G is specially designed for data transmission rather than voice. LTE is 4G technology with WiMAX introduced in 2010 .LTE is termed as “MAGIC-Mobile multimedia, anytime anywhere, Global mobility support, and customized personal service”. LTE supports peak download rate of 1 Gbps and upload rate of 500 Mbps. It uses packet switching and message switching.
It uses concatenated codes for error correction. Its frequency band is 2-8 GHz. For wider bandwidth to get access to multimedia, video conferencing, full motion video, uninterrupted global roaming and easy access to all the services, it is needed. We can easily watch streaming videos, games, location services, chat, online stores, information, entertainment etc. using LTE. So, it was the need of LTE.