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LTE is essential for 3GPP Release 8 determinations. LTE can be worked in either frequency division duplex or time division duplex (TDD) mode, likewise alluded to as LTE FDD and TD-LTE. LTE upholds data rates of 300Mbps in downlink and 75Mbps in the uplink direction. It gives a lot higher information speeds and incredibly further developed execution just as lower working expenses.

LTE network area:

A LTE network region is separated into three distinct kinds of geological regions clarified beneath:

  • The MME pool areas

This is a region through which the portable can transfer from one place to another without a difference in serving MME. Each MME pool region is constrained by at least one MMEs on the organization.

  • The S-GW administration regions

This is a region served by at least one serving gateways S-GW, through which the versatile can transfer from one place to another without a difference in serving gateway.

  • The Tracking areas

The MME pool areas and the S-GW service areas are both made from smaller, non-overlapping units known as tracking areas (TAs). They are like the area and directing regions from UMTS and GSM. It will be utilized to follow the areas of mobiles. 

How does LTE work?

A LTE network utilizes the multiuser variation of the orthogonal frequency-division multiplexing (OFDM) modulation scheme, called orthogonal frequency-division multiple access (OFDMA), for its downlink signal. OFDMA empowers the LTE downlink to send information from a base station to numerous clients at higher information rates than 3G, with improved spectral proficiency. Single-transporter FDMA is utilized for the uplink signal, which diminishes the send power expected of the versatile terminal.

The upper layers of LTE depend on Transmission Control Protocol/Internet Protocol, which brings about an all-Internet Protocol organization, similar to that of wired correspondences. LTE upholds mixed information, voice, video and informing traffic. LTE-A utilizations multiple-input, multiple-output (MIMO) antenna innovation like that utilized in the IEEE 802.11n wireless local area network standard. MIMO and OFDM empower a higher signal-to-noise ratio at the receiver, giving better remote organization inclusion and throughput, particularly in thick metropolitan regions.

LTE-A needs gadgets to be fitted with an exceptional chip. Broadcom, Nvidia and Qualcomm all make chips that assist LTE-A. The cell phones assists LTE-A in present day. 

LTE Architecture:

The significant level network architecture of LTE comprises of the accompanying three primary parts:

  • User Equipment (UE).
  • The Evolved UMTS Terrestrial Radio Access Network (E-UTRAN).
  • The Evolved Packet Core (EPC).

The User Equipment (UE)

The inside design of the user equipment for LTE is indistinguishable from the one utilized by UMTS and GSM, which is a Mobile Equipment (ME). The portable equipment contains the accompanying significant modules:

  • Mobile Termination (MT): This handles all the correspondence capacities.
  • Terminal Equipment (TE): This ends the information streams.
  • Universal Integrated Circuit Card (UICC): This is otherwise called the SIM card for LTE equipment. It is used to process an application known as the Universal Subscriber Identity Module (USIM).

USIM stores client explicit information were basically the same as 3G SIM cards. This keeps the data about the client’s telephone number, home organization personality, security keys and so on. 


The E-UTRAN manages the radio correspondences between the versatile and the evolved packet core and has the evolved base stations, called eNodeB or eNB. Each eNB is a base station that controls the mobiles in at least one cell. The base station that is transmitting data is known as its serving eNB.

The Evolved Packet Core (EPC) 

The evolved packet core involves parts like the Earthquake and Tsunami Warning System (ETWS), the Equipment Identity Register (EIR) and Policy Control and Charging Rules Function (PCRF).

  • The Home Subscriber Server (HSS):  part has been conveyed from UMTS and GSM. It contains data about all the network administrator’s endorsers.
  • The Packet Data Network (PDN) Gateway (P-GW): It transmitting packet data networks PDN, utilizing the SGi interface. Packet data network is recognized by an access point name (APN). The PDN gateway plays a similar part as the GPRS support node (GGSN) and the serving GPRS support node (SGSN) with UMTS and GSM.
  • The serving gateway (S-GW) acts as a switch, and sends information between the base station and the PDN gateway.
  • The mobility management entity (MME): It handles the significant level activity of the versatile utilizing flagging messages and a Home Subscriber Server (HSS).
  • The Policy Control and Charging Rules Function (PCRF) is answerable for policy control decision-making, and for managing the flow-based charging activities in the Policy Control Enforcement Function (PCEF). 

LTE interfaces:

LTE interfaces and protocol

The main interfaces in LTE are Uu, S1-MME, X2, S1-U, S11 and S5

  •  LTE Uu

This is the air interface between UE and eNB. LTE layer 1 is dealt with later. RRC is the protocol that is used for communication between UE and eNB. Above RRC there is a NAS layer in UE. This NAS layer terminates at MME and eNB shall silently pass the NAS messages to MME.

  • LTE S1-MME

eNB and MME communicate using this IP interface. S1-AP is an application layer interface. The transport protocol used here is SCTP. (Stream control transmission protocol).

  • LTE X2: 

This interface is used by an eNB to communicate with other eNB. This again is an IP interface with SCTP as transport. X2-AP is the application protocol used by eNB’s to communicate.

  • LTE S11: 

An IP interface between MME and SGW! GTPv2 is the protocol used at the application layer. GTPv2 runs on UDP transport. This interface must and should run GTPv2.

  • LTE S5: 

This is the interface between SGW and PGW. This again is an IP interface and has two variants. S5 can be a GTP interface or PMIP interface. The PMIP variant is used to support non-trusted 3GPP network access.

  • LTE S1-U: 

User plane interface between eNB and SGW! GTP-U v1 is the application protocol that encapsulates the UE payload. GTP-U runs on UDP.

LTE Features:

LTE standard tends to the enhancing capacity of 3G UMTS to what in particular will ultimately be 4G versatile correspondences innovation. E-UTRA is the air point of interaction of LTE. Its principle highlights are:

  • It assist for both FDD and TDD correspondence frameworks, just as half-duplex FDD with a similar radio access innovation.
  • It also support for all recurrence groups as of now utilized by IMT frameworks by ITU-R.
  • LTE has expanded spectrum adaptability: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz wide cells are normalized.
  • In LTE, the MBSFN (multicast-broadcast single-frequency network) is the feature that can convey administrations, for example, Mobile TV utilizing the LTE framework and is a contender for DVB-H-based TV broadcast just LTE viable gadgets gets LTE signal.
  • LTE support low data transfer latencies, lower latencies for handover and association arrangement time than with past radio access advancements.
  • Further developed assist for portability, exemplified by help for terminals moving at up to 350 km/h (220 mph) or 500 km/h (310 mph) contingent upon the recurrence.
  • LTE has quicker download and transfer speeds than 2G and 3G. In 2021, the worldwide normal LTE download speed is 17 Mbps, and the normal upload speed is 12 Mbps.
  • With voice over LTE (VoLTE), clients can converse with others without encountering slack or jitter.
  • LTE can get higher data rates, 300Mbps peak downlink and 75 Mbps peak uplink. 
  • LTE is an optimal innovation to help high information rates for the administrations like voice over IP (VOIP), web based interactive media, videoconferencing.
  • LTE assists Multiple Input Multiple Output transmissions, which permit the base station to send information streams over a similar transporter at the same time.

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