22-05-2012, 10:35 AM
4G-TECHNOLOGY and application
[attachment=22652]
Introduction:
In a world of increasing technological needs, the mobile Internet can play a significant role resolving the user’s capacity and connectivity needs. There is lots of research and suggestions around the 4G concept, where vendors and operators are trying to define it based on their preferred technology and strategic planning. At the end of 2007, the total mobile subscribers were 3 billion., with GSM based users to grow over 2
billion.
Need for 4G services:
A 4G technology is expected to provide a comprehensive and secure IP based solution where facilities such as voice, data and streamed multimedia will be provided to users on an "Anytime, Anywhere" basis and at much higher data rates compared to previous generations.
4G Features :
1. The infrastructure and the terminals of 4G will have almost all the standards from 2G to 4G implemented.
2. Although legacy systems are in place to adopt existing users, the infrastructure for 4G will be only packet-based (all-IP).
3. Some proposals suggest having an open Internet platform.
4. Technologies considered to be early 4G include: FLASH OFDM.
Linear transmitter power amplifier:
An OFDM signal exhibits a high peak-to-average power ratio (PAPR) because the independent phases of the sub-carriers mean that they will often combine constructively. Handling this high PAPR requires:
1. a high-resolution digital-to-analog converter (DAC) in the transmitter
2. a high-resolution analog-to-digital converter (ADC) in the receiver
a linear signal chain
[attachment=22652]
Introduction:
In a world of increasing technological needs, the mobile Internet can play a significant role resolving the user’s capacity and connectivity needs. There is lots of research and suggestions around the 4G concept, where vendors and operators are trying to define it based on their preferred technology and strategic planning. At the end of 2007, the total mobile subscribers were 3 billion., with GSM based users to grow over 2
billion.
Need for 4G services:
A 4G technology is expected to provide a comprehensive and secure IP based solution where facilities such as voice, data and streamed multimedia will be provided to users on an "Anytime, Anywhere" basis and at much higher data rates compared to previous generations.
4G Features :
1. The infrastructure and the terminals of 4G will have almost all the standards from 2G to 4G implemented.
2. Although legacy systems are in place to adopt existing users, the infrastructure for 4G will be only packet-based (all-IP).
3. Some proposals suggest having an open Internet platform.
4. Technologies considered to be early 4G include: FLASH OFDM.
Linear transmitter power amplifier:
An OFDM signal exhibits a high peak-to-average power ratio (PAPR) because the independent phases of the sub-carriers mean that they will often combine constructively. Handling this high PAPR requires:
1. a high-resolution digital-to-analog converter (DAC) in the transmitter
2. a high-resolution analog-to-digital converter (ADC) in the receiver
a linear signal chain