Long Term Evolution (LTE)

Sachidananda Sahu

Table of Contents Introduction to LTE Introduction to Mobile Communication Generations In Mobile Technology Key Technology of LTE LTE Targets Architecture of LTE Protocol Stack LTE- Advantages Major Applications Current market scenario Beyond LTE Conclusion References

Introduction to LTE• It is broadband network technology beyond 3G

developed by 3GPP of release 8.• Proposed by NTT DoCoMo of Japan in 2004• Specification finalized in January 2008.• Promises data transfer up to 100Mbps(Mobile).

Introduction to Mobile Communication

Video Radio/Alarm Internet

e-Mail

Music Composer

CameraCamera

GamesGames

SMS/TextSMS/Text

MP3 AudioMP3 Audio

TelevisionTelevision

Cont...

Generations In Mobile Technology

IS-95 IS-136 & PDCGSM-

EDGEGPRS

HSCSDIS-95B

Cdma2000-1xRTTCdma2000-1xEV,DV,DO

Cdma2000-3xRTT

W-CDMAEDGE

TD-SCDMA

2G

3G

2.5G

3GPP3GPP2

4G

1G

• Analog FM – AMPS – Introduced in US• Access Technique –Frequency Division Multiple Access (FDMA)• Data rate : 9.6 kbps• Three parts to the communications

– Voice channels– Paging Channels– Control Channels

Drawbacks : Poor voice quality Poor hand-off Limited capacity of the available spectrum Non – Sharing Channel

Frequency

2G

• GSM, IS-136, IS-95 (CDMA one) standard introduced• Digital modulation• Due to digital error checking, sound quality increased• Circuit Switched communication• Data rate : 19.3 kbps• SMS & E-mail feature introduced

• Drawbacks:• Very Low data rate• Limited internet browsing• Weaker digital signal will not reach a cell tower in less

populous area

General Packet Radio ServicesData rates up to ~ 171.2 kbpsPacket switched resources not tied up all the timeContention based. EfficientWAP introduced

GPRSEDGE

Enhanced Data Rates for Global EvolutionUses 8PSK modulation3x improvement in data rate on short distancesRequires New hardware & softwareData rate from 384Kbps to 547Kbps

HSCSD

High Speed Circuit Switched DataCircuit switched communication & Error ControlSpeed from 14.4Kbps to 57.6KbpsGood for real-time applications Inefficient -> ties up resources

GSM9.6kbps (one timeslot)GSM Data

GSM

2.5G

3G ITU has defined the demands for third generation mobile

network with IMT-2000 standard. Characteristics

– A single family of compatible standard that can be used worldwide.

- Support for both packet-switched and circuit switched data transmission

- Data rates up to 2 Mbps

- High spectrum efficiency Supported technologies

– UMTS– cdma2000

Currently they divided in to two 3g champs– 3GPP – UMTS– 3GPP2- cdma 2000

UMTS Architecture

HSPA(Popularly known as 3.5G)

• Its an UMTS upgrade(Release 5/6)• HS-DSCH(High Speed Downlink Shared Channel)• HS-SCCH(High Speed Share control channel) • Supports up to 21Mbps downlink and 5 Mbps uplink speed.• Features

- Fast Scheduling- Backward compatibility with 3G- Enhanced Air Interface

LTE(Release 8/9)....

• 3GPP LTE is a project of the Third Generation Partnership Project.

• Improves the UMTS (Universal Mobile Telecommunications System) mobile phone standard.

Key technology of LTE

These two are the key technologies which enable LTE to have spectral efficiency and High Speed communication-OFDMA/SC-FDMA-MIMO

Features :• Reduced power consumption• Higher RF power amplifier efficiency (less battery power

used by handsets)• Fully packet switched domain

– No more circuit switched network• Scalable bandwidth 1.4,3,5,10,15,20 MHz

• Peak data rate – 100 Mbps• Up to 200 active users in a cell (5 MHz)• Mobility – Optimized for 0 ~ 15 km/h. – 15 ~ 120 km/h supported with high performance.• Enhanced multimedia broadcast service • Spectrum flexibility: 1.25 ~ 20 MHz• Duplexing supports FDD & TDD• Spectral Efficiency – SC - FDMA & OFDMA• Modulation type : QPSK,QAM

LTE Targets

Architecture of LTE

SAE/EPC

Main Elements and interfaces of LTE

• E-Node-B– This is Node B element of UMTS with extra intelligence– Latency improves as the job of RNC is done by E nB– It usage OFDMA for downlink and SC-FDMA for uplink for User

equipment• X2 Interface

– It is used to connect two E-nB• S1 Interface

– E-nB usage S1-MME interface to connect MME (control plane )– S1-U interface to connect S-GW(data plane)– These two are collectively called S1 interface

• MME/S-GW(Memory management entity/Serving Gateway)– Collectively called the EPC(Evolved packet network) or

SAE(System architecture evolution)– Authentication– Mobility management– Packet routing and forwarding

OFDMA and SC-FDMA

user1

user2user3user4

MIMO

Protocol Stack

LTE Advantages

Major Applications

• High speed multimedia– like HD Video calling, Video on demand, On line

gaming• GPS• Large data file transfer• Automatic vehicle location

Current market scenario World market: Major commercial implementation in china, japan, America Major players worldwide – NTT docomo, Verizon mobile Major LTE handset makers- Samsung(new GALAXY series),

HTC(Thunderbolt series), Nokia(N8, E7)

Indian Market: Bharti airtel, Aircel, Reliance, Tikona have the license Currently, only airtel provides services in Bangalore, Pune

and Kolkata.

Beyond LTE...

• LTE-Advanced(considered as True 4G)• Data rate : 100Mbps(High mobility) up to 3 Gbps• Higher spectral efficiency• Increased number of simultaneous active subscribers• Backward compatible with LTEs

Conclusion

LTE is well positioned to meet the requirements of next-generation mobile networks with existing 3GPP/3GPP2 operators.

It enables operators to offer high performance, mass-market mobile broadband services.

LTE will be available not only in next-generation mobile phones but also in notebooks, cameras.

References

1. T.S.Rappaport, Wireless communication2. www.4gltemall.com3. www.3gpplte.com4. www.3gpp.org