Reference signaling scheme using compressed feedforward codebooks for multi-user, multiple input, multiple output (MU-MIMO) systems
US7961807B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2007 |
| Grant date | Jun 14, 2011 |
| Priority date | — |
| Expiry date | Nov 17, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/0421
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A multi-user multiple input multiple output (MIMO) downlink beamforming system with limited feed forward (200) is provided to enable precoding matrix information to be efficiently provided to a subset of user equipment devices (201.i), where zero-forcing transmit beamformers (wi) are computed at the base station (210) and assembled into a precoding matrix (W). The precoding matrix is encoded using a compact reference signal codebook (225, 207.i) for forward link signaling, either by sending bits indicating the index of the transmission matrix used, or by transmitting one or more precoded pilots or reference signals wherein the pilot signals are precoded using vectors uniquely representative of the transmission matrix used which includes candidate reference signal matrices which meet a predetermined condition number requirement, such as a condition number threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.