Mobility Management Challenges and Issues in 4G Heterogeneous Networks
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Transcript of Mobility Management Challenges and Issues in 4G Heterogeneous Networks
Mobility Management Challenges and Mobility Management Challenges and Issues in 4G Heterogeneous NetworksIssues in 4G Heterogeneous Networks
By By AJAL.A.JAJAL.A.J
Towards 4GTowards 4GUser centric, user controlled services
andcontext-aware applications
Technologies
ChallengesChallenges
• Convergence/integration/inter-working of all existing and emerging fixed and mobile (wired and wireless) networks including broadcast
• Simple to select and easy to use desired services
• Universal and low cost terminals
IP Technology
Agent Technology
Reconfigurable Technology
The Internet
IP backbone
BillingVHE
Signalling Gateway
WAP Accounting
UMTS
Broadcast Networks (DAB, DVB-T)
Satellite FES
GSM / GPRS
Context-aware informationCentre
IP-based micro-mobility Wireless
LANs
ISPSIP Proxy Server
Inter-Working
Global coverage
National coverage
Local area coverageWireless LANs
DAB and DVB-T, DVB-S
2G, 3G and 4G Cellular
Personal area coverage
Hierarchical coverage layers for 4G
Satellite
Regional coverage
Wireless PANs
Vertical Handover
Horizontal Handover
IP-based backbone
Multi-Agency Seamless Mobility
The Future Home…
DSL/Cable or MSOTelephone
Wireless camera
Wireless media
gateway
NAS for MP3 & Video
Content
Integrated networks, content,and entertainment systems
Managed Security
Managed Voice
Managed Wireless
Success Story @ Work – Madras Pharma
T.Nagar
Sholinganallur
• Point to Point and Point to Multi Point• Backhaul spanning to 12kms from T.Nagar (H.O) to Sholinganallur (Factory)
Success Story @ Work – Residency Group Hotels
-Enable Point – to – Point Connectivity ( 1KM )
- Centralized accounting and reservation system
- Hotspot Zones for wireless internet access
Main Building Annexe
Usman Road
• Point – to – Point Connectivity ( 600 meters )
• Enabling centralized billing and accounting systems
Success Story @ Work – GRT Thangamaligai
The complexity of the problem: user prospective
From a user prospective
Multiple Heterogeneous network operators
part of
Multiple user environments accessed using
Multiple heterogeneous devices
owned by
LaptopPDA
UMTS DVB WLAN
heterogeneous users
A Heterogeneous Network Architecture
UTRAN WLAN 4G RAN
PAN
Wireless Access Network
Core Network Future Internet
Intra-Cell PAN Ad-hoc Network PAN PAN
PAN
Re-configurable Technology
What does Reconfiguration mean?
“Reconfiguration refers to the software re-definition and/or adaptation of every
element within each layer of the communication chain.”
BasebandProcessing
UserData
A/D Converter
D/A Converter
RF Front End
Re-configurable Technology
Benefits• Users
• Operators
• Manufacturers
- Select network depending on service requirements and cost.- Connect to any network – Worldwide roaming.-Access to new services.
- Respond to variations in traffic demand (load balancing).- Incorporate service enhancements and improvements.- Correction of software bugs and upgrade of terminals.- Rapid development of new personalised and customised services
- Single platform for all markets.- Increased flexible and efficient production.
Re-configuration Procedures
ReconfigurationTrigger
Mode Identification
Mode Negotiation
Software Download
Mode Switch Decision
ModeMonitoring
ReconfigureTerminal
Initiated by network operator or user
Download software modules that are
required for the target mode
What networks are available?
What is the most suitable network (based on QoS, user preferences etc.)?
Decision on preferred mode
Aggressive frequency re-use High spectrum efficiency
Increased co-channel interference
Downlink Switched Beam Antenna
SIGNALOUTPUT
INTERFERENCE
SIGNAL
SIGNALOUTPUT
BEAMFORMERWEIGHTS
Uplink Adaptive Antenna
SIGNAL
INTERFERENCE
BE
AM
FO
RM
ER
BEAMSELECT
Smart antennas provide substantial interference suppression for enhanced performance
Smart Antennas for 4G• Key enhancement technique to improve system capacity and user experience• Leverage Smart Antennas currently in development/deployment for IS-136 & GSM
Path Loss and Fading Challenge
Delay Spread
Rayleigh Fading
Path Loss
rapid fading of 20 to 30 dB(power varies by 100 to 1000 timesin level at rates of about 100 times per second)
path loss up to ~ 150 dB(that is a 1 followed by 15 zeroes)
Reflected signalsarrive spread outover 5 to 20microsecond
4G Cellular Interference Challenge
0.001
0.01
0.1
1
-5 0 5 10 15 20 25
1|3 reuse
2|6 reuse
3|9 reuse
4|12 reuse
7/21 reuse
Signal to Interference ratio in dB
Cum
ulat
ive
Pro
babi
lity
Each base station is equippedwith three 120 degree directionalantennas to reduce interference& improve capacity
MIMO Measured Channel CapacityPotential Capacity Relative to a Single Antenna System
• Capacity increase close to 4 times that of a single antenna is possible with 4 transmit and 4 receive antennas
• Capacity for pedestrians is similar to mobile users
Space-Time Coding
OFDM for 4G Wireless
~ 6 kHz
~ 800 tones
~ 5 MHz
• OFDM is being increasingly used in high -speed information transmission systems:
- European HDTV- Digital Audio Broadcast (DAB)- Digital Subscriber Loop (DSL)- IEEE 802.11 Wireless LAN
5 MHz channels~ 6 KHz tones~ 13/26 MHz sample rate2048 FFT size (160 usec OFDM blocks)256/512 sample OFDM block guard timeQPSK & 16-QAM modulation adaptive modulation/coding1 to 2 msec time-slots in 20 to 40 msec frames
Mobile OFDM parameters: ex.