16-08-2012, 05:05 PM
Fourth Generation Cellular Systems
[attachment=31758]
A View of 4G
Domain of 4G extends beyond 1G, 2G, and 3G
> 2 Mbps in a wide-area mobile system (> 20 Mbps peak)
Could coexist with 2G and 3G
4G is not necessarily defined by the bit rate, but by a significant advance in system capability beyond what can be achieved with 3G
Some Key Challenges
Coverage
Transmit power limitations and higher frequencies limit the achievable cell size
Capacity
Current air interfaces have limited peak data rate, capacity, and packet data capability
Spectrum
Location and availability are key issues
Lower carrier frequencies (< 5 GHz) are best for wide-area coverage and mobility
Spectrum
Carrier frequency has a larger impact on cell size than data rate
In order to enable wide-area coverage, 4G needs “mobile friendly” spectrum (ideally less than 5 GHz)
Mobile devices have low transmit power, limited antenna gain, and predominately non-line-of-sight propagation
Fixed wireless systems are more easily able to take advantage of higher carrier frequencies
No movement -> low Doppler
Higher transmit power
Power consumption/heat dissipation less critical
Line-of-sight more likely
High-gain, high-elevation antenna
4G Concept System
A demonstration of broadband mobile systems in Schaumburg, Illinois
A one-directional broadband downlink carrier on DVB-T (WA9XHI)
A narrowband uplink via a cellular data connection (Sprint CDMA data)
Proving ground for asymmetric mobile broadband
Develop application understanding to apply to broadband air interface designs
Platform to demonstrate custom applications
Increasing levels of integration
Phase 1 – Vehicular mobility with a larger off-the-air receiver – May 2000
Phase 2 – Personal mobility with an integrated laptop receiver – Progressing
[attachment=31758]
A View of 4G
Domain of 4G extends beyond 1G, 2G, and 3G
> 2 Mbps in a wide-area mobile system (> 20 Mbps peak)
Could coexist with 2G and 3G
4G is not necessarily defined by the bit rate, but by a significant advance in system capability beyond what can be achieved with 3G
Some Key Challenges
Coverage
Transmit power limitations and higher frequencies limit the achievable cell size
Capacity
Current air interfaces have limited peak data rate, capacity, and packet data capability
Spectrum
Location and availability are key issues
Lower carrier frequencies (< 5 GHz) are best for wide-area coverage and mobility
Spectrum
Carrier frequency has a larger impact on cell size than data rate
In order to enable wide-area coverage, 4G needs “mobile friendly” spectrum (ideally less than 5 GHz)
Mobile devices have low transmit power, limited antenna gain, and predominately non-line-of-sight propagation
Fixed wireless systems are more easily able to take advantage of higher carrier frequencies
No movement -> low Doppler
Higher transmit power
Power consumption/heat dissipation less critical
Line-of-sight more likely
High-gain, high-elevation antenna
4G Concept System
A demonstration of broadband mobile systems in Schaumburg, Illinois
A one-directional broadband downlink carrier on DVB-T (WA9XHI)
A narrowband uplink via a cellular data connection (Sprint CDMA data)
Proving ground for asymmetric mobile broadband
Develop application understanding to apply to broadband air interface designs
Platform to demonstrate custom applications
Increasing levels of integration
Phase 1 – Vehicular mobility with a larger off-the-air receiver – May 2000
Phase 2 – Personal mobility with an integrated laptop receiver – Progressing