31-01-2013, 09:41 AM
4G Wireless Technology
[attachment=48987]
4G Wireless: Definition
• 4G Wireless:
– Defined by the ITU (International
Telecommunication Union).
– A 4G system targets peak data rates of
approximately 100 Mbps for high mobility
service.
– A 4G system targets peak data rates of
approximately 1 Gbps for low mobility/
fixed service.
– Shall support required channel bandwidths
from 5 to 20 MHz with an optional 40 MHz
channel allowed.
– Shall support both TDD and FDD duplexing
technologies with UL/DL configurable ratios
for both.
– Network architecture will be all IP based.
– Must utilize MIMO technology.
– Latency:
• Data - 10 ms. In both UL & DL
• Idle state to active state – 100 ms.
• Site handoff – 50 ms. Intrafrequency, 150 ms.
Interfrequency.
4G Wireless: Technologies used in 4G
• MIMO - Minimum antenna configurations.
– For the BS - a minimum of 2 Tx and 2 Rcv antennas
– For the MS - a minimum of 1 Tx and 2 Rcv antennas
• MIMO Techniques -
– Beam forming – makes use of multiple antennas to
steer or focus signal in a particular direction. Can
reduce adjacent site self-interference & add reach.
– SU-MIMO (Single User MIMO)
• Transmitting parallel & unique data streams in
the same frequency-time resource to a single
user. (Spatial Multiplexing)
• Improves individual users throughput.
• MIMO Techniques - continued
– MU-MIMO (Multiple User MIMO)
• Transmitting parallel & unique data streams
in the same frequency-time to multiple
users. (Spatial multiplexing)
• Improves sector/site capacity throughput.
– STBC - Space Time Block Coding
• The simplest of the STBCs transmits
multiple copies of a single data stream
across a number of antennas which
improves the SNR of the received data to
improve the reliability of data-transfer.
4G Wireless: Pre 4G - WiMAX
• 802.16-2004 (d) is often called Fixed WiMAX
– Fixed WiMAX does not support Mobility.
– Does not support 1 cell frequency reuse.
– Utilizes OFDM-256 FFT (Orthogonal
Frequency-Division Multiple)
– Also supports OFDMA 2048, but only
OFDM 256 FFT is specified in WiMAX
802.16d profiles.
– Supports both TDD (Time Division
Duplexing) and FDD (Frequency Division
Duplexing) services
[attachment=48987]
4G Wireless: Definition
• 4G Wireless:
– Defined by the ITU (International
Telecommunication Union).
– A 4G system targets peak data rates of
approximately 100 Mbps for high mobility
service.
– A 4G system targets peak data rates of
approximately 1 Gbps for low mobility/
fixed service.
– Shall support required channel bandwidths
from 5 to 20 MHz with an optional 40 MHz
channel allowed.
– Shall support both TDD and FDD duplexing
technologies with UL/DL configurable ratios
for both.
– Network architecture will be all IP based.
– Must utilize MIMO technology.
– Latency:
• Data - 10 ms. In both UL & DL
• Idle state to active state – 100 ms.
• Site handoff – 50 ms. Intrafrequency, 150 ms.
Interfrequency.
4G Wireless: Technologies used in 4G
• MIMO - Minimum antenna configurations.
– For the BS - a minimum of 2 Tx and 2 Rcv antennas
– For the MS - a minimum of 1 Tx and 2 Rcv antennas
• MIMO Techniques -
– Beam forming – makes use of multiple antennas to
steer or focus signal in a particular direction. Can
reduce adjacent site self-interference & add reach.
– SU-MIMO (Single User MIMO)
• Transmitting parallel & unique data streams in
the same frequency-time resource to a single
user. (Spatial Multiplexing)
• Improves individual users throughput.
• MIMO Techniques - continued
– MU-MIMO (Multiple User MIMO)
• Transmitting parallel & unique data streams
in the same frequency-time to multiple
users. (Spatial multiplexing)
• Improves sector/site capacity throughput.
– STBC - Space Time Block Coding
• The simplest of the STBCs transmits
multiple copies of a single data stream
across a number of antennas which
improves the SNR of the received data to
improve the reliability of data-transfer.
4G Wireless: Pre 4G - WiMAX
• 802.16-2004 (d) is often called Fixed WiMAX
– Fixed WiMAX does not support Mobility.
– Does not support 1 cell frequency reuse.
– Utilizes OFDM-256 FFT (Orthogonal
Frequency-Division Multiple)
– Also supports OFDMA 2048, but only
OFDM 256 FFT is specified in WiMAX
802.16d profiles.
– Supports both TDD (Time Division
Duplexing) and FDD (Frequency Division
Duplexing) services