18-10-2010, 05:28 PM
4G Network Architectures
Final report to survey
System issues
Selected concepts for 4G
Self-organizing ,Ad-hoc network for 4G
“4G” Design Challenges
Although 3G is an important first step, several basic issues still need to be addressed for next generation wireless systems:
Fast/reliable broadband radios (PHY/MAC) with QoS
~100 Kbps 1-10 Mbps with adaptivity, link reliability & Qos
Scalable system capacity for mass-market services
high service penetration implies ~Gbps/Sq-Km
Integration of multiple radio technologies into single IP network
unified mobility architecture
New networking modes, e.g. multicast, multihop & peer-to-peer
...lower-cost infrastructure, networks that grow organically
4G System Issues
4G System Issues: Scaling of Capacity
The grand vision of ubiquitous wireless and pervasive computing leads to a serious capacity problem.
4G System Issues: Scaling of Capacity (cont.)
2G cellular:
avail BW ~ 5 Mhz, spectral eff ~ 0.2-0.3 bps/Hz
max capacity ~ 100 Kbps avg, 1 Mbps peak (with packet MAC) per sq-Km
3G Cellular:
avail BW ~ 25 Mhz, spectral eff ~ 0.3-0.5 bps/Hz
max capacity ~ 1 Mbps avg, 10 Mbps peak (with packet MAC) per sq-Km
Wireless LAN (802.11x, Hiperlan):
avail BW ~ 100 Mhz, spectral eff ~ 0.2-0.3 bps/Hz
max capacity ~ 100 Mbps avg, 1 Gbps peak per sq-Km
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