4. What to learn…?
Overview of 1G
Overview of 2G
What is 3G ?
Why 3G technology ?
Difference & comparison between 1G, 2G,
3G.
Why 3G technology ?
Effects of 3G technology ?
5. What to learn (contd…?
Benefits of 3G ?
Issue hampering 3G ?
What is 4G ?
What's New in 4G?
Features of 4G Networks ?
6. Overview of 1G…?
1st
generation of wireless telecom
Introduced in the 1980
Provide only analog services
Based on AMPS (Advanced
mobile phone service)
7. Overview of 2G
2nd
generation of wireless telecom
Launched in 1991
Provides Digital services for voice Quality
2G introduced data services for mobile
starting with SMS text messages
Based on TDMA (time division multiplexing
access)
8. What is 3G ?
3rd
generation of wireless telecom
Mostly used with mobiles and handsets
Faster communication services
which includes
Voice
Fax
Internet
10. Why 3G technology ?
Higher bandwidth enables a range of new applications.
For the consumer
Video streaming, TV broadcast
Video calls, video clips – news,
music, sports Enhanced gaming, chat,
location services.
For business
High speed teleworking / VPN access
Video conferencing
Real-time financial information
11. Effect of 3G technology
Mobile Internet connectivity
Mobile email
Mobile Interview
Multimedia services, such as digital photos
taken by and shared via wireless handsets
Wireless application downloading
Real-time multiplayer gaming
Enhanced emergency and location-based
services
12. Benefits of 3G
Higher call volumes and support for multimedia
data applications, such as video and
photography.
Faster data transfer rates
Free or cheap calls worldwide
Capability to determine geographic position of
mobiles and report it
Worthwhile for users that need connectivity on
the move
13. Issues hampering its growth
High spectrum licensing fees for the 3G services
Huge capital required to build infrastructure for
3G services
Health impact because of electromagnetic
waves
Prices are very high for 3G mobile services
Will 2G users switch to 3G services?
Takes time to catch up as the service is new.
14. What is 4G ?
A wireless access technology and is the successor of
3G.
Called "3G and Beyond".
Enables seamless roaming between technologies.
Plans on releasing the first commercial network in 2010.
NTT DoCoMo Company is testing 4G communication at
100 Mbps while moving, and 1 Gbps while stationary.
15. 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.
16. 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 any where
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
17. Features of 4G Networks (contd…)
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).
20. 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
21. One of the most challenging problems facing
deployment of 4G technology is how to
access several and different mobile and
wireless networks
There are two possible architectures
Multimode Devices
Overlay Network
4G Wireless Networks Challenges
First Challenge:
22. First Challenge: Accessing
Different Networks
1. Multimode Devices Architecture
A single physical terminal with multiple interfaces
to access the different wireless networks
23. 1. Multimode Devices Architecture
Advantages:
Improve call completion
Expand 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
25. First Challenge: Accessing
Different Networks
2. Overlay Network Architecture
A user accesses an overlay network consisting
of several UAPs
UAPs Functions:
Select a wireless network based on availability
and user choices
Store IPs of user, network and devices
26. Overlay Network Architecture
Advantages:
Simplify hardware of device
Supports single billing
Disadvantages:
More network devices
Handoff Mechanism between UAPs:
Performed by overlay network rather than the
user or device
28. 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
29. 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
1. Location Management
30. •) . 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
Handoff Management (cont.)
Handoff Management Challenges
31. Vertical & Horizontal handoff will increase
System load (increasing control packets)
Packet losses
Handover latency
Challenges in Handoff
Management
35. 3G (including 2.5G) 4G
Major Requirement Driving
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 IP 5.0
All IP (IP6.0)
3G vs. 4G
37. Overview
Motivation
Effect of propagation
diagram of a radio
Signal Propagation
Large scale path loss
Small scale fading
38. Motivation for Wireless
propagation
Wireless channel is vastly different from wired counterpart
Different access mechanisms
Common channel but …
State of channel at each node can vary drastically
E.g.: Sender thinks that channel is free but receiver senses a busy
channel – Packet drop?
Unreliable channel
Highly sensitive to environment (surroundings) and weather
Modest bandwidth
Effects of Propagation has a high impact on higher layer
protocols
E.g.: Are the assumptions made by TCP protocol valid under
wireless channel?
39. Signal Propagation Effects
Free-space path loss
Fading
Scattering
Diffraction
Refraction
Multipath propagation
40. Free-space path loss
Free-space path loss (FSPL) is
the loss in signal strength of an electromagnetic wave
that would result from a line-of-sight path through free
space (usually air), with no obstacles nearby to cause
reflection or diffraction.
41. Fading
In wireless communications,
fading is deviation of the attenuation affecting a signal
over certain propagation media. The fading may vary with
time, geographical position or radio frequency
42. Scattering
Scattering is a general physical process where some
forms of radiation, such as light, sound,
43. Multipath propagation
Multipath is the propagation phenomenon that results in radio signals
reaching the receiving antenna by two or more paths.
Causes
atmospheric ducting,
ionosphere reflection
refraction