Long Term Evolution (LTE)

Long Term Evolution (LTE)

Long Term Evolution (LTE) is a 4G wireless broadband technology developed by the Third Generation Partnership Project (3GPP), an industry trade group. LTE is a set of enhancements to the Universal Mobile Telecommunications System(UMTS) which was introduced in 3rd Generation Partnership Project-Release 8.

The LTE specification provides downlink peak rates of at least 100 Mbps, an uplink of at least 50 Mbps. TE supports scalable carrier BW from 20 MHz down to 1.4 MHz.

Although there are many new features introduced by LTE, I will start with a few of them !!

• S1-flex Mechanism

The S1-flex concept provides support for network redundancy and load sharing of traffic across network elements in the CN, the MME and the SGW, by creating pools of MMEs and SGWs and allowing each eNB to be connected to multiple MMEs and SGWs in a pool.

• Network Sharing

The LTE architecture enables service providers to reduce the cost of owning and operating the network by allowing the service providers to have separate CN (MME, SGW, PDN GW) while the E-UTRAN (eNBs) is jointly shared by them. This is enabled by the S1-flex mechanism by enabling each eNB to be connected to multiple CN entities. When a UE attaches to the network, it is connected to the appropriate CN entities based on the identity of the service provider sent by the UE.

WCDMA

WCDMA - Its a 3G wireless technology. WCDMA stands for Wideband Code Division Multiple Access. Its a radio access technology for UMTS.

WCDMA provides data rates of 2Mbps for stable users and around 384 Mbps while travelling.
But with HSDPA combined with WCDMA, a user can get data rates upto 14.4 Mbps in Downlink and 5.8 Mbps in Uplink.

WCDMA is a successor to GSM. It uses IMS as its underlying core Network structure.

More Later...

CDMA - Digital 2G after GSM

Code-Division Multiple Access.

CDMA is a digital wireless technology. It is a general type of technology, implemented in many specific technologies. But the term "CDMA" is also commonly used to refer to one specific family of technologies (IS-95 and CDMA2000) that competes with technologies such as GSM.

CDMA is a "spread spectrum" technology, which means that it spreads the information contained in a particular signal of interest over a much greater bandwidth than the original signal.

Unlike many competing technologies, CDMA has no hard limit for the number of users who may share one base station (tower). Instead, with CDMA, additional users can connect until the base station determines that call quality would suffer beyond a set limit.

CDMA (IS-95) systems have been in commercial operation since 1995. CDMA networks operate in the 800 and 1900 MHz frequency bands with primary markets in the Americas and Asia. IS-95 CDMA systems are sometimes referred to as cdmaOne. The next evolutionary step for CDMA to 3G services is cdma2000.

GSM - 2G Digital Technology

GSM Stands for Global System for Mobile communications. Its the most widely used 2G

Its promoter, the GSM Association, estimates that 82% of the global mobile market uses the standard. GSM is used by over 2 Billion people across more than 212 countries and territories.
One of the main feature of GSM is the GLOBAL Roaming between mobile phone operators which allows the subscribers to use their cellphones in more than one country!! technology in the world right now.

GSM networks operate in four different Frequency Range or Bands:
Most GSM networks operate in the 900 MHz or 1800 MHz bands. Some countries in the Americas (including Canada and the United States) use the 850 MHz and 1900 MHz bands because the 900 and 1800 MHz frequency bands were already allocated.

Modulation: The Modulation used in GSM is GMS, a kind of continuous-phase frequency Shift Keying.


More Later......