12-10-2010, 02:54 PM
This article is presented by:
Rodger E. Ziemer
IEEE Communications Society
Distinguished Lecturer Program
Rules for Efficient Multiple Access
Three laws
Know the channel
Minimize interference to others
Mitigate interference received from others
Requirements of wireless multiple access
Channel measurement
Channel control and modification
Multiple user channel isolation
Why CDMA?
Higher capacity
Improved performance in multipath by diversity
Lower mobile transmit power = longer battery life
Power control
Variable transmission rate with voice activity detection
Allows soft handoff
Sectorization gain
High peak data rates can be accommodated
Combats other-user interference = lower reuse factors
What is Third Generation?
Flexible support of multiple services
Voice
Messaging – email, fax, etc.
Medium-rate multimedia – Internet access, educational
High-rate multimedia – file transfer, video
High-rate interactive multimedia – video telecon-ferencing, telemedicine, etc.
Mobility: quasi-stationary to high-speed platforms
Global roaming: ubiquitous, seamless coverage
Evolution from second generation systems
For more information about this article,please follow the link:
http://googleurl?sa=t&source=web&cd=1&ve...2000_2.ppt&ei=kCi0TPDtH4ycvgOEr8mLCg&usg=AFQjCNFQK8aqWBcZ7LR9NcKFcNe72ZI9CA
Rodger E. Ziemer
IEEE Communications Society
Distinguished Lecturer Program
3G CDMA - WCDMA and cdma2000
Rules for Efficient Multiple Access
Three laws
Know the channel
Minimize interference to others
Mitigate interference received from others
Requirements of wireless multiple access
Channel measurement
Channel control and modification
Multiple user channel isolation
Why CDMA?
Higher capacity
Improved performance in multipath by diversity
Lower mobile transmit power = longer battery life
Power control
Variable transmission rate with voice activity detection
Allows soft handoff
Sectorization gain
High peak data rates can be accommodated
Combats other-user interference = lower reuse factors
What is Third Generation?
Flexible support of multiple services
Voice
Messaging – email, fax, etc.
Medium-rate multimedia – Internet access, educational
High-rate multimedia – file transfer, video
High-rate interactive multimedia – video telecon-ferencing, telemedicine, etc.
Mobility: quasi-stationary to high-speed platforms
Global roaming: ubiquitous, seamless coverage
Evolution from second generation systems
For more information about this article,please follow the link:
http://googleurl?sa=t&source=web&cd=1&ve...2000_2.ppt&ei=kCi0TPDtH4ycvgOEr8mLCg&usg=AFQjCNFQK8aqWBcZ7LR9NcKFcNe72ZI9CA
