Lead Inventor:
Xiaodong Wang, Ph.D.
Digital Wireless Communication Systems Face Multi-Path Fading Challenges
Digital wireless communication systems such as wireless routers and mobile phones have gained widespread adoption in recent years. A common problem with digital communication systems is multi-path fading as multiple copies of a signal propagate from a transmitter to a receiver via different paths. To address multi-path fading problems, as well as other forms of signal degradation, orthogonal frequency divisional multiplexing (OFDM) has been adopted in many digital wireless systems. OFDM operates by sending digital signals across many different orthogonal subcarriers (or channels). Unlike some other forms of communication which attempt to send a large amount of data over a single carrier at high speed, OFDM spreads the data across multiple subcarriers at lower speeds, making it more robust to interference problems. To further improve the performance of OFDM wireless systems, multiple- input and multiple-output (MIMO) configurations of OFDM systems have been adopted. In a typical configuration, a MIMO system may use two or more transmitting antennas and two or more receiving antennas. By controlling signal output on these transmitting antennas, beamforming can be used to control the beam shape of the transmitted signal. By controlling the shape of the beam transmitted by the antennas, various forms of signal degradation, including multi-path fading, can be reduced.
Beamforming and Power Control for Optimized Mobile Wireless Communications
This technology proposes a novel solution to the problem of beamforming and power control in the downlink of a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system. The power control strategy is based on feedback generated by the receiver and used by the transmitter to select a proper transmitting energy level from a list of possible candidates to minimize the bit error rate of the system over each OFDM subcarrier. The system is implemented by using efficient 1-bit feedback control to minimize computational complexity and optimize the system performance over its long term use.
Applications:
• Next generation mobile wireless communications
Advantages:
• Fully functional in a fast fading scenario
• Can be used in multi-carrier system to update optimum energy level
• More accuracy in tracking eigenmodes
• Does not need pilot symbols
Patent Status: Patent Pending (US 11/957,385) ~ see link below.
Licensing Status: Available for Licensing and Sponsored Research Support
Publications: Merli, F.Z. Vitetta, G.M. Xiaodong Wang,
MIMO Precoding and Power Control based on 1-bit Feedback, Signals, Systems and Computers, 2007. ACSSC 2007. Conference Record of the Forty-First Asilomar Conference on
