UMTS to LTE

Question 1

General Functions of Components?

Answer 1

Core Network
Radio Access Network
UE

Question 2

Core Network?

Answer 2

Carries traffic from one RAN to another RAN.
Hosts controlling/management servers.
Hosts the network intelligence.

Question 3

Radio Access Network?

Answer 3

Provides radio access to the user
Connects the user to the core network and services
Implements air interface

Question 4

User Equipment?

Answer 4

Provides user interface to the user

Implements air interface to connect to the RAN

Question 5

RNC?

Answer 5

Radio Network Controller

Passes user’s voice information and data packets between the NodeB and CN

Question 6

In UMTS, sectors are called?

Answer 6

Cells

Question 7

In GSM the whole area is called?

Answer 7

Cell

Question 8

Handover?

Answer 8

When a mobile moves from one part of the network to another, it has to stop communicating with one cell and start communicating with the next cell along.

Question 9

Two different techniques of Handover?

Answer 9

Handover - for mobiles that are actively communicating with the network.
Cell Reselection - for mobiles that are on standby.

Question 10

Hard Handover?

Answer 10

Break before make.

- Happens when a UE can connect only one BS simultaneously.

Question 11

Example of Hard Handover?

Answer 11

GSM

Question 12

Soft Handover?

Answer 12

Make before break

- Happens when UE can connect more than one BS simultaneously.

Question 13

Example of Soft Handover?

Answer 13

UMTS

Question 14

Inter-System Handover?

Answer 14

Handover between different systems

Question 15

Example of Inter-System Handover?

Answer 15

From UMTS to GSM

Question 16

Media GW?

Answer 16

Processes, routes voice traffic.

Simillar to MSC function in GSM

Question 17

MSC Server?

Answer 17

Controls the network using signalling.

Setup, manage, teardown connections.

Question 18

GGSN?

Answer 18

Act as interfaces to outside data network

Question 19

SGSN?

Answer 19

Route data between the BSs and the GGSN

Handle the signalling messages to set up, manage and tear down the data streams.

Question 20

HSS?

Answer 20

central database

contains information about all subscribers

Question 21

PDU?

Answer 21

Protocol Data Unit

• Output data structure of any protocol
• Delivers this data structure to lower layer protocol as payload to that protocol.

Question 22

SDU?

Answer 22

Service Data Unit

• Payload received from upper layer protocol
• Header is added to this to create PDU of this protocol

Question 23

Motivations for LTE?

Answer 23

The growth of mobile data

Increasing the System Capacity

Question 24

Shannon channel capacity formula gives?

Answer 24

The maximum data rate achievable in an AWGN channel.

Question 25

To increase the System Capacity we need?

Answer 25

Increase the numbers of channels in cell.
Replicate the cells, hence all channels.
Replicate the all available channels within a cell.

Question 26

EPS?

Answer 26

Evolved Packet System

Question 27

RAT?

Answer 27

Radio Access Technology