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A Method for Reducing the Known Pilot Symbols Overhead for High-Mobility SFBC OFDM-Based Wireless Communication Systems

Project ID: 1751-AP
Available for licensing

Background

The rich scattering environment of today's urban areas, combined with the high mobility of wireless subscribers, impose adapting techniques which are flexible against time and frequency fluctuation of the communication channel. Orthogonal frequency division multiplexing (OFDM) is a very powerful modulation technique suited for rich scattering environments, and Alamouti space-frequency block coding (SFBC) is a time-fluctuation resilience coding technique exploiting two antennas at the transmitter in order to introduce diversity into the communication system. These two methods combined together are a promising solution for high-mobility rich scattering urban environments.

However, coherent detection at the receiver requires knowledge of the communication channel. This is done through periodically multiplexing known pilot symbols into the downlink data stream. The required number of these known pilot symbols has a direct relationship with the time/frequency fluctuations of the channel (i.e., how fast the mobile subscriber is moving and how rich is the scattering environment). As the number of required known pilot symbols increases, the overhead associated with transmitting them becomes significant. It is extremely desirable to reduce this overhead.

Invention Description

This invention reduces the number of required known pilot symbols in a communication system adapting SFBC-OFDM technique by 25%, and does so without any additional hardware and with minimal increase in the computational complexity of both the transmitter and the receiver. This invention is both backward compatible and scalable.

Benefits

Reduces the number of required known pilot symbols in SFBC-OFDM systems by 25%
Able to achieve results by adding minimal complexity to the system

Features

Backward compatible
Scalable

Market Potential/Applications

Coherent Alamouti space-frequency block coded (SFBC) orthogonal frequency division multiplexing (OFDM) based systems

UT Researcher

Robert W. Heath, Jr., Ph.D., Electrical and Computer Engineering, The University of Texas at Austin
Ali Y. Panah, Electrical and Computer Engineering, The University of Texas at Austin

OTC Contact Information

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