lte & ims intro

Ericsson Internal | 2012-09-11 |

LTE & IMS:AN INTRODUCTION


Technology Evolution


DATA RATE Evolution


MOVING TO LTE

The 3GPP Long Term Evolution (LTE) represents a major advance in cellular technology designed to meet carrier needs for high-speed data and media transport.

LTE infrastructure is designed to be as simple as possible to deploy and operate, through flexible technology.

It can be deployed in a wide variety of frequency bands. LTE offers scalable bandwidths, from less than 5MHz up to 20MHz, together with support for both FDD paired and TDD unpaired spectrum.

The LTE–SAE architecture reduces the number of nodes, supports flexible network configurations and provides a high level of service availability.

Furthermore, LTE–SAE will inter operate with GSM, WCDMA/HSPA, TD-SCDMA and CDMA


LTE ARCHITECTURE


MULTIPLEXING TECHNIQUE in LTE

OFDM:• LTE uses OFDM for the down link – that is, from the base

station to the terminal. • OFDM meets the LTE requirement for spectrum flexibility and

enables cost-efficient solutions for very wide carriers with high peak rates.

SC-FDMA:• The LTE uplink transmission scheme for FDD and TDD mode

is based on SC-FDMA (Single Carrier Frequency Division Multiple Access).

• This is to compensate for a drawback with normal OFDM, having a very

high Peak to Average Power Ratio (PAPR) which leads to expensive and inefficient power amplifiers, increasing the cost of the terminal and also drains the battery faster.


APPROACHES

The main Problem while implementing IMS or LTE was How to Map them with the already existing services and Provide high quality services. For this 3 Possible approaches were there:

VOLTE: Voice over LTE

CSFB: Circuit switched fallback

SVLTE: Simultaneous voice and LTE


VOLTE

• VOLTE i.e. Voice over LTE , basically refers to IMS itself.

• Here the voice services are delivered as data services within the IMS network.

• The services are provided by using standard Protocols like SIP: Session Initiation Protocol


CSFB • CSFB basically refers to Circuit Switched Fallback approach.• In CSFB: LTE just provides data services, and when a voice call

is to be initiated or received, it will fall back to the CS domain.• For this solution, Operators just need to Upgrade the existing

MSCs so as to support this approach.• But the disadvantage will be a Longer Call setup delay

Disadvantages• Each time a voice call is made, Handover needs to be done

between the LTE network and CS i.e. circuit switched network.• The CS network, will not be able to provide the high data

speeds and Clarity that IMS can provide. (CS network:7-10Mbps,IMS:100 Mbps).

• The Handover Procedure and low data rates will provide a unavoidable delay in call setup and hence the call setup will take a longer time


MORE about CSFB

As shown above, there is a MSC-server, which will route the Voice call to CS domain and Data Applications to LTE network.


SVLTE • SVLTE: refers to Simultaneous Voice over LTE• The handset works simultaneously in the LTE and CS modes, with

the LTE mode providing data services and the CS mode providing the voice service.

• This solution is solely based on the Handset, and does not require much modifications in the network.

• Disadvantage: the phone can become expensive with high power consumption.


WHY IMS ?

• With the increasing need for high data rates and more of interactive services, it became essential for the telecom operators to Provide high speed and improved Quality services.

• For moving to high data speeds, the telecom operators needed to upgrade to either LTE or IMS, both providing high data rates of around 300MB/s DL and 79.4 Mbps UL.


IMS

IP Multimedia Subsystem (IMS) is a generic architecture for offering multimedia and voice over IP services, define by 3rd Generation Partnership Project (3GPP). IMS is access independent as it supports multiple access types including GSM, WCDMA, CDMA2000, WLAN, Wire line broadband and other packet data applications.

volte (voip) approach is based on the IP Multimedia

Subsystem (IMS) network.


Advantages of IMS

• Multi access and device flexibility: IMS can provide any service, on any screen, anywhere ie any electronic device that can understand IP can be used for communicating to another device.

• Multimedia with high quality and security: The consumer expects multimedia services to be delivered with quality, security and reliability

• Global reach: Consumers can share multimedia services with friends around the world who use other telecom operators.

• Experience Sharing: The consumers can see where their ‘buddies’ are, their ‘presence’ and what methods they can use to communicate with each of them.

• Convenience: Brings person-to-person communication values together and provides ease of use, by the availability of everything on one device.


INTER SYSTEM OPERABALITY


• MVNO stands for mobile network virtual operator• It does not have its own radio Spectrum and shares the

radio resources with a already existing MNO (Mobile Network Operator)

• MVNOs need to issue their own SIM cards with their own Mobile Network Codes (MNCs)

Advantages: 1) Expanded choices – with MVNOs, the customer would

have a wider range of organizations offering them a complete mobile service;

2) Possibly lower retail prices – The retail prices will depend upon the terms of agreement between MVNOs and MNOs.

3) Potentially wider range of services: use of the IN (Intelligent Network) enables them to provide enhanced services

MVNO CONCEPT


SAMPLE MVNO NETWORK

As shown in the diagram, the call made by a MVNO subscriber uses the radio resources of a MNO ,and is routed to the MVNO MSC by the MNO MSC(or MSC-server) and finally to the Destination


SHUBHABRATA MUKHERJEE

1ST LA- LGI & ZIGGO

lte & ims intro

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