System and method for interpolation based transmit beamforming for MIMO-OFDM with partial feedback
US7676007B1 · kind B1 · utility
Inventors
Key dates
| Filing date | Jul 21, 2005 |
| Grant date | Mar 9, 2010 |
| Priority date | — |
| Expiry date | Aug 29, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/006
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Transmit beamforming with receive combining uses the significant diversity provided by multiple-input multiple-output (MIMO) systems, and the use of orthogonal frequency division multiplexing (OFDM) enables low complexity implementation of this scheme over frequency selective MIMO channels. Optimal beamforming uses channel state information in the form of the beamforming vectors corresponding to all the OFDM subcarriers. In non-reciprocal channels, this information should be conveyed back to the transmitter. To reduce the amount of feedback information, transmit beamforming combines limited feedback and beamformer interpolation. In this architecture, the receiver sends back a fraction of information about the beamforming vectors to the transmitter, and the transmitter computes the beamforming vectors for all subcarriers through interpolation of the conveyed beamforming vectors. Since a beamforming vector is phase invariant and has unit norm, a linear spherical interpolator uses additional parameters for phase rotation. These parameters are determined at the receiver in the sense of maximizing the minimum channel gain or capacity. The interpolator maybe combined with beamformer quan…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.