Back to Wireless and Communications list

A Method and Apparatus for Adaptive Mode Switching and Rate Selection for Energy Efficient MIMO Systems

Project ID: 1734-AP
Available for licensing

Background

It is generally accepted that MIMO (multiple transmit and multiple receive antennas) achieves better energy efficiency than SIMO (single transmit and multiple receive antennas) thanks to spatial multiplexing gain. However, when circuit power is considered, MIMO may consume more power than SIMO at low spectra efficiency. This is because MIMO has multiple antennas and transmission chains and therefore consumes more fixed processing power (called circuit power hereafter). Thus circuit power hinders the use of MIMO on the uplink. Mitigating the adverse impact of circuit power remains crucial to enabling the use of MIMO for the uplink. This invention enables the use of two transmit antennas at the mobile terminal by adaptively switching between MIMO and SIMO.

Invention Description

This invention is to save energy consumption of mobile terminals (MTs) and extend the battery lifetime. Specifically, it reduces the uplink transmit energy consumption by adaptively switching transmission mode between Multiple-Input Multiple-Output (MIMO) and Single-Input Multiple-Output (SIMO). This invention is named CUTE, which stands for Conserve Users Terminals' Energy.

The key idea is simple. When the system is underutilized, the MT operates with SIMO at low spectral efficiency to save energy, but when congested, the MT operates with MIMO at high spectral efficiency to increase throughput. This is done in an adaptive way considering the two aspects - dynamic network traffic and channel variations.

Benefits

Adaptive switching can save uplink transmission energy by more than 50% as compared to MIMO without substantially changing user-perceived performance.

Features

Exploits dynamic traffic and channel variations to save transmission energy.

Market Potential/Applications

Emerging broadband wireless access systems such as WiMAX, WiMAX2, 3GPP-LTE, LTE-Advance. Mobile terminals who have two transmit antennas can use this invention to reduce the transmit power consumption and save energy as well as maintain the desired target throughput; i.e., to achieve Quality of Service (QoS).

IP Status

One U.S. patent application filed

UT Researcher

Robert W. Heath, Jr., Ph.D., Electrical and Computer Engineering, The University of Texas at Austin
Gustavo A. De Veciana, Ph.D., Electrical and Computer Engineering, The University of Texas at Austin
Chan-Byoung Chae, The University of Texas at Austin
Hongseok Kim, Electrical and Computer Engineering, The University of Texas at Austin

OTC Contact Information

Jitendra Jain, Licensing Specialist
jjain@otc.utexas.edu
512-471-9055