04-06-2012, 10:56 AM
4G MOBILE
4G MOBILE.ppt (Size: 1.62 MB / Downloads: 44)
INTRODUCTION
4G – 4th Generation Mobile System is combination of several technologies of optimal usage.
Key Features from Users’ Point of View
High usability: anytime, anywhere, and with any technology
Support for multimedia services at low transmission cost
Personalization
Attaining Gbits/s/km at low cost.
Telecommunications services + data and multimedia services
Challenge to Migrate to 4G
Mobile station
System
Service
Multipath – The challenge
The RF signal travels through multiple paths
The RF channel is characterized by a delay profile
Problematic when delay spread is comparable to symbol duration
Multipath – The solution
OFDM modulates in parallel multiple narrow band sub-carriers
Multipath duration becomes short relative to symbol duration
Pilot and guard sub-carriers are also inserted
KEY 4G TECHNOLOGIES
OFDM.
SOFTWARE DEFINED RATIO.
MIMO.
INTERLAYER OPTIMIZATION.
HANDOVER AND MOBILITY.
SOFTWARE DEFINED RADIO
SDR benefits from high processing power to develop multi-band, multi-standard base station and terminal.
To increase network capacity, an operator will reconfigure its network by adding several modems at a base transceiver station (BTS).SDR makes this easy.
Powerful aid to provide ,multi-standard, multi-band equipment with reduced effort and costs.
CONCLUSION
Disruptive technologies are needed to achieve high capacity at low cost, but it can still be done in a progressive manner.
The key enablers are:
Sufficient spectrum, with associated sharing mechanisms.
Coverage with two technologies: parent (2G, 3G, WiMAX) for real-time delivery, and discontinuous Pico cell for high data rate delivery.
Caching technology in the network and
terminals.
OFDM and MIMO.
IP mobility.
Multi-technology distributed architecture.
Fixed-mobile convergence (for indoor service).
Network selection mechanisms.