05-12-2012, 11:45 AM
The Evolution of TDMA to 3G & 4G Wireless Systems
[attachment=42564]
AT&T Wireless Services
AT&T serves over 14 million subscribers with digital
TDMA technology and some remaining analog technology,
and provides packet data service with CDPD technology
TDMA parameters
30 KHz channels (like analog & CDPD)
20 msec speech frames
24.3 kbaud symbol rate
3 time-slots/users
7.4 kbps ACELP speech coding
1/2-rate channel coding on important bits interleaved over 2 bursts in 40 msec
Differential pi/4-QPSK modulation
EDGE Technology
Enhanced Data-rates for Global Evolution
Evolutionary path to 3G services for GSM and TDMA operators
Builds on General Packet Radio Service (GPRS) air interface and networks
Phase 1 (Release’99 & 2002 deployment) supports best effort packet data at speeds up to about 384 kbps
Phase 2 (Release’2000 & 2003 deployment) will add Voice over IP capability
GPRS Airlink
General Packet Radio Service (GPRS)
Same GMSK modulation as GSM
4 channel coding modes
Packet-mode supporting up to about 144 kbps
Flexible time slot allocation (1-8)
Radio resources shared dynamically between speech and data services
Independent uplink and downlink resource allocation
EDGE Airlink
Extends GPRS packet data with adaptive modulation/coding
2x spectral efficiency of GPRS for best effort data
8-PSK/GMSK at 271 ksps in 200 KHz RF channels supports 8.8 to 59.2 kbps per time slot
Supports peak rates over 384 kbps
Requires linear amplifiers with < 3 dB peak to average power ratio using linearized GMSK pulses
Initial deployment with less than 2x 1 MHz using 1/3 reuse with EDGE Compact as a complementary data service
GPRS Networks
consists of packet wireless access network and IP-based backbone
shares mobility databases with circuit voice services and adds new packet switching nodes (SGSN & GGSN)
will support GPRS, EDGE & WCDMA airlinks
provides an access to packet data networks
Internet
X.25
provides services to different mobile classes ranging from 1-slot to 8-slot capable
radio resources shared dynamically between speech and data services
EDGE Evolution
Best effort IP packet data on EDGE
Voice over IP on EDGE circuit bearers
Network based intelligent resource assignment
Smart antennas & adaptive antennas
Downlink speeds at several Mbps based on wideband OFDM and/or multiple virtual channels
MIMO Radio Channel Measurements
Multiple antennas at both the base station and terminal can significantly increase data rates with sufficient multipath
Ability to separate signals from closely spaced antennas has been demonstrated indoors and in AT&T-Lucent IS-136 field trial
Lucent has demonstrated 26 bps/Hz in 30 kHz channel with 8 Tx and 12 Rx antennas indoors
AT&T has performed measurements on 4 Tx by 4 Rx antenna configurations in full mobile & outdoor to indoor environments
Multiple Input Multiple Output Wireless
RX diversity - HF, terrestrial microwave, cellular….
TX frequency offset diversity & simulcasting for paging - 70’s
Adaptive array processing in military systems
TX diversity - 80’s
frequency offset (channel decoding combining)
delay (equalizer combining)
Optimum combining for cellular (multipath channels) - 80’s
Space-division multiple access - 80’s & 90’s
angle-of-arrival based
multi-path based (supports co-location & multi-channels per user)
MIMO - 80’s & 90’s
Multiple spatial channels using adaptive antenna arrays
BLAST - successive interference cancellation combined with coding
Space-Time coding
[attachment=42564]
AT&T Wireless Services
AT&T serves over 14 million subscribers with digital
TDMA technology and some remaining analog technology,
and provides packet data service with CDPD technology
TDMA parameters
30 KHz channels (like analog & CDPD)
20 msec speech frames
24.3 kbaud symbol rate
3 time-slots/users
7.4 kbps ACELP speech coding
1/2-rate channel coding on important bits interleaved over 2 bursts in 40 msec
Differential pi/4-QPSK modulation
EDGE Technology
Enhanced Data-rates for Global Evolution
Evolutionary path to 3G services for GSM and TDMA operators
Builds on General Packet Radio Service (GPRS) air interface and networks
Phase 1 (Release’99 & 2002 deployment) supports best effort packet data at speeds up to about 384 kbps
Phase 2 (Release’2000 & 2003 deployment) will add Voice over IP capability
GPRS Airlink
General Packet Radio Service (GPRS)
Same GMSK modulation as GSM
4 channel coding modes
Packet-mode supporting up to about 144 kbps
Flexible time slot allocation (1-8)
Radio resources shared dynamically between speech and data services
Independent uplink and downlink resource allocation
EDGE Airlink
Extends GPRS packet data with adaptive modulation/coding
2x spectral efficiency of GPRS for best effort data
8-PSK/GMSK at 271 ksps in 200 KHz RF channels supports 8.8 to 59.2 kbps per time slot
Supports peak rates over 384 kbps
Requires linear amplifiers with < 3 dB peak to average power ratio using linearized GMSK pulses
Initial deployment with less than 2x 1 MHz using 1/3 reuse with EDGE Compact as a complementary data service
GPRS Networks
consists of packet wireless access network and IP-based backbone
shares mobility databases with circuit voice services and adds new packet switching nodes (SGSN & GGSN)
will support GPRS, EDGE & WCDMA airlinks
provides an access to packet data networks
Internet
X.25
provides services to different mobile classes ranging from 1-slot to 8-slot capable
radio resources shared dynamically between speech and data services
EDGE Evolution
Best effort IP packet data on EDGE
Voice over IP on EDGE circuit bearers
Network based intelligent resource assignment
Smart antennas & adaptive antennas
Downlink speeds at several Mbps based on wideband OFDM and/or multiple virtual channels
MIMO Radio Channel Measurements
Multiple antennas at both the base station and terminal can significantly increase data rates with sufficient multipath
Ability to separate signals from closely spaced antennas has been demonstrated indoors and in AT&T-Lucent IS-136 field trial
Lucent has demonstrated 26 bps/Hz in 30 kHz channel with 8 Tx and 12 Rx antennas indoors
AT&T has performed measurements on 4 Tx by 4 Rx antenna configurations in full mobile & outdoor to indoor environments
Multiple Input Multiple Output Wireless
RX diversity - HF, terrestrial microwave, cellular….
TX frequency offset diversity & simulcasting for paging - 70’s
Adaptive array processing in military systems
TX diversity - 80’s
frequency offset (channel decoding combining)
delay (equalizer combining)
Optimum combining for cellular (multipath channels) - 80’s
Space-division multiple access - 80’s & 90’s
angle-of-arrival based
multi-path based (supports co-location & multi-channels per user)
MIMO - 80’s & 90’s
Multiple spatial channels using adaptive antenna arrays
BLAST - successive interference cancellation combined with coding
Space-Time coding