14-07-2012, 02:30 PM
Power Management of MIMO Network Interfaces on Mobile Systems
[attachment=27663]
Introduction
Conventional “Single Input Single Output” (SISO) systems were favored for simplicity and low-cost but have some shortcomings:
Outage occurs if antennas fall into null
Switching between different antennas can help
Energy is wasted by sending in all directions
Can cause additional interference to others
Sensitive to interference from all directions
Output power limited by single power amplifier
MIMO Wireless Systems
Multiple Input Multiple Output (MIMO) systems with multiple parallel radios improve the following:
MIMO networks interfaces are high speed wireless networks.
Outages reduced by using information from multiple antennas
Transmit power can be increased via multiple power amplifiers
Higher throughputs possible
Transmit and receive interference limited by some techniques
Antennas
An antenna is an electrical conductor or system of conductors to send/receive RF signals
Transmission - radiates electromagnetic energy into space
Reception - collects electromagnetic energy from space
In MIMO, each antenna can be used for transmission and reception.widley used is micro tip antenna in MIMO
MIMO Channel Capacity
The instantaneous channel capacity C Increases in MIMO networks due to multi paths for transmission.
The instantaneous channel capacity C can be calculated as
C= min (MT,MR) log 2 (P/MT) + constant b/s/Hz
The capacity expression presented was over one realization of the channel. Capacity is a random variable and has to be averaged over infinite realizations to obtain the true ergodic capacity. Outage capacity is another metric that is used to capture this
MIMO Design Criterion
There are two basic types of MIMO technology:
Beam forming MIMO
Standards-compatible techniques to improve the range of existing data rates using transmit and receive beamforming
Also reduces transmit interference and improves receive interference tolerance
Spatial-multiplexing MIMO
Allows even higher data rates by transmitting parallel data streams in the same frequency spectrum
Fundamentally changes the on-air format of signals
Requires new standard (11n) for standards-based operation
Proprietary modes possible but cannot help legacy devices
[attachment=27663]
Introduction
Conventional “Single Input Single Output” (SISO) systems were favored for simplicity and low-cost but have some shortcomings:
Outage occurs if antennas fall into null
Switching between different antennas can help
Energy is wasted by sending in all directions
Can cause additional interference to others
Sensitive to interference from all directions
Output power limited by single power amplifier
MIMO Wireless Systems
Multiple Input Multiple Output (MIMO) systems with multiple parallel radios improve the following:
MIMO networks interfaces are high speed wireless networks.
Outages reduced by using information from multiple antennas
Transmit power can be increased via multiple power amplifiers
Higher throughputs possible
Transmit and receive interference limited by some techniques
Antennas
An antenna is an electrical conductor or system of conductors to send/receive RF signals
Transmission - radiates electromagnetic energy into space
Reception - collects electromagnetic energy from space
In MIMO, each antenna can be used for transmission and reception.widley used is micro tip antenna in MIMO
MIMO Channel Capacity
The instantaneous channel capacity C Increases in MIMO networks due to multi paths for transmission.
The instantaneous channel capacity C can be calculated as
C= min (MT,MR) log 2 (P/MT) + constant b/s/Hz
The capacity expression presented was over one realization of the channel. Capacity is a random variable and has to be averaged over infinite realizations to obtain the true ergodic capacity. Outage capacity is another metric that is used to capture this
MIMO Design Criterion
There are two basic types of MIMO technology:
Beam forming MIMO
Standards-compatible techniques to improve the range of existing data rates using transmit and receive beamforming
Also reduces transmit interference and improves receive interference tolerance
Spatial-multiplexing MIMO
Allows even higher data rates by transmitting parallel data streams in the same frequency spectrum
Fundamentally changes the on-air format of signals
Requires new standard (11n) for standards-based operation
Proprietary modes possible but cannot help legacy devices