Transcript View File - University of Engineering and Technology, Taxila

Wireless Communication and Networks
Applications of Wireless
Communication
Wireless Communication
Technologies
Wireless Networking and
Mobile IP
Wireless Local Area
Networks
Student Presentations and
Research Papers
4G Technology Features & Challenges
http://web.uettaxila.edu.pk/CMS/AUT2012/teWCNms/
Outline

Introduction
 What
is 4G?
 What's
New in 4G?

3G vs. 4G

4G Network Features

How 4G works

Challenges

Summary
What is 4G?

A wireless access technology that is the successor of 3G.

Called "3G and Beyond".

Enables seamless roaming between technologies.

First commercial network deployed in 2010.

NTT DoCoMo tested 4G communication at 100 Mbps
while moving, and 1 Gbps while stationary.
What's New in 4G?

Entirely packet-switched networks.

All network elements are digital.

Higher bandwidths to provide multimedia
services at lower cost (up to 100Mbps).

Tight network security.
Features of 4G Networks

4G networks are all-IP
(Internet Protocol) based
heterogeneous networks

This will allow users to:
 Select any system at
any time and anywhere


Use Multiple systems at
the same time (e.g.
GPS and WLANs and
CDMA)
A wide range of
applications using only one
4G integrated terminal.
Features of 4G Networks (cont.)

Support interactive multimedia services:
teleconferencing, wireless Internet, etc.

Wider bandwidths, higher bit rates.

Global mobility and service portability.

Low cost.

Scalability of mobile networks (>10 times the capacity of 3G).
3G vs. 4G
3G (including 2.5G)
4G
Major Requirement Driven
Architecture
Predominantly voice driven data was always add on
Converged data and voice over IP
Network Architecture
Wide area cell-based
Hybrid – Integration of Wireless LAN
(WiFi, Bluetooth) and wide area
Speeds
384 Kbps to 2 Mbps
20 to 100 Mbps in mobile mode
Frequency Band
Dependent on country or
continent (1800-2400 MHz)
Higher frequency bands (2-8 GHz)
Bandwidth
5-20 MHz
100 MHz (or more)
Switching Design Basis
Circuit and Packet
All digital with packetized voice
Access Technologies
W-CDMA, 1xRTT, Edge
OFDM and MC-CDMA (Multi Carrier
CDMA)
Forward Error Correction
Convolution rate 1/2, 1/3
Concatenated coding scheme
Component Design
Optimized antenna design,
multi-band adapters
multi-band adapters, Smarter
Antennas, software multiband and
wideband radios
IP
A number of air link protocols,
including IPv4
All IP (IPv6)
From : www.mobileinfo.com
How 4G works (working principle)

The IP address is based on IPv6.

IPv4:
X.X.X.X
example: 216.37.129.9

IPv6:
4 × IPv4
(32 bits)
(128 bits)
example:
216.37.129.9 , 79.23.178.229 , 65.198.2.10 , 192.168.5.120
home
address
care-of
address
mobile IP
address
local network
address
IPv4 vs. IPv6
IPv4
IPv6
Structure
32 bits
128 bits
Security
Poor security
Enhanced security
Function
Addressing
1.
2.
Multi-function with mobility
Plug & Play (Auto-Configuration)
The 4G mobile network(s)
HAPS
Satellite
GSM
Wireline or Wireless
Networks
(Internet)
Services
Bluetooth
Care-ofMobile
Add. IP Add.
WLAN
UMTS
Content
ADSL
Home Add.
Care-of Add.
OFDM
Very wide
area
Unspecified
Wide area
TDMA
FDD
WCDMA
TD-CDMA
Metropolitan area
OFDM
TDD
Local area
Direct Sequence
Frequency
Hopping
Personal
area
4G Systems Challenges


To migrate current systems to 4G with the features
mentioned previously, researchers are facing a number
of challenges
These challenges are grouped into the following
different aspects:
 Accessing Different Networks:
 Multimode Devices
 Overlay Network
 Terminal
Mobility
 Location Management
 Handoff Management
4G Wireless Networks Challenges
First Challenge: Accessing Different Networks


One of the most challenging problem facing
deployment of 4G technology is how to access
different heterogeneous mobile and wireless
networks
There are two possible architectures
 Multimode Devices
 Overlay Networks
First Challenge: Accessing Different Networks
1. Multimode Devices Architecture




A single physical terminal with
multiple interfaces to access the
different wireless networks
Advantages:
 Improve call completion
 Expanded coverage area
 Reliable coverage in case of
network, link or switch failure
Disadvantages:
 Complexity in the hardware of
the device
Handoff Mechanism:
Performed by the user, device or
network
Multimode Devices Architecture (cont.)
To reduce the complexity of the hardware in the device the most promising
technology is to adapt the software defined radio approach
bandpass filter
BPF
Low noise amplifier
LNA
Analog/digital converter
Baseband
ADC
DSP
Digital
Analogue
An ideal software radio system
reprogrammable
User
Multimode Devices Architecture (cont.)
Challenges in software radio technology

High number of antennas: Still It is
impossible to have just one antenna and one
LNA to cover the bands of all 4G wireless
network technologies

The slow speed of ADCs. The speed of the
current fastest ADC is still two to three times
slower than required
First Challenge: Accessing Different Networks
2. Overlay Network Architecture





A user accesses an overlay network
consisting of several UAPs
UAP Functions:
 Select a wireless network based
on availability and user choices
 Store IPs of user, network and
devices
Advantages:
 Simplify hardware of the device
 Supports single billing
Disadvantages:
 More network devices
Handoff Mechanism between UAPs:
Performed by overlay network rather
than the user or device
4G Wireless Networks Challenges
Second Challenge: Terminal Mobility



In order to provide wireless services at any time
and anywhere, terminal mobility is a must in 4G
infrastructure
Terminal mobility allows mobile clients to roam
across geographical boundaries of the wireless
networks
There are two main issues in terminal mobility:


location management
handoff management
Second Challenge: Terminal Mobility
1. Location Management

The system tracks and locates a mobile
terminal for possible connection

Location management involves handing all
the information about

Roaming terminals such as original and current
location cells
 Authentication information
 QoS capabilities
Second Challenge: Terminal Mobility
2. Handoff Management


Maintain ongoing communication when the terminal roams
IP changes during handoff :
IPv6 within the same cell:
216.37.129.9,
home address
79.23.178.229,
care-of address
65.198.2.10,
mobile IP address
192.168.5.120
local network address
Second Challenge: Terminal Mobility
2. Handoff Management
IPv6 when the terminal roams to another cell:
216.37.129.9,
home address
79.23.178.229,
care-of address
65.198.2.10,
mobile IP address
192.168.5.120
local network address
Handoff Management (cont.)
Handoff Management Challenges
• Horizontal handoff is
performed when the terminal
moves from one cell to another
within the same wireless
system.
• Vertical handoff is performed
when the terminal moves
between two different wireless
systems (e.g., from WLAN to
GSM) .
Challenges in Handoff Management

Vertical & Horizontal handoff will increase
 System load (increasing control packets)
 Packet losses
 Handover latency

Hard correct handoff time: because measuring
handoffs is done among different wireless
systems
Summary

The key concept behind 4G systems is
integrating the capacities of all of the existing
mobile technologies through advanced
technologies

The IP address system used in 4G is based on
the IPv6 technology.

4G networks is still in the development stage,
and in order to utilize their new features many
challenges must be addressed.
References

Upkar Varshney and Radhika Jain, Issues in Emerging 4G Wireless
Networks, Georgia State Jain, Issues in Emerging 4G Wireless Networks,
Georgia State University.
Available:http://www.ee.oulu.fi/~skidi/teaching/mobile_and_ubiquitous_multim
edia_2002/issues_in_emerging_4G_wireless_networks.pdf

Erik Fledderus, Bingulac, Broadband Radio; a vision on 4G, KPN Research,
The Netherlands. Available:
http://www.brabantbreedband.nl/publications/URSIGA2002%20ER%20Fledderus.pdf

Ibrahim,Jawad “4G Features,” Bechtel Telecommunications Technical Journal
(Vol.1 No.1), Dec. 2002

Yu Hui, Suk and Kai Hau Yeung, City University of Hong Kong: Challenges in
the Migration to 4G Mobile Systems. Available:
http://ieeexplore.ieee.org/iel5/35/28028/01252799.pdf

Wikipedia, the free encyclopedia. http://en.wikipedia.org/wiki/4G
References (cont.)

Z. Theodore, “Migration toward 4G Wireless Communications,” IEEE Wireless
Communication, June. 2004

U. Narumi, O. Toru, and M. Tatsuro “Overview of Fourth-generation Mobile
Communication System,” NTT Technical Review (Vol.2 No.0), Sep. 2004