Apparatus and Method for Hybrid Type Multi-User Multi-Antenna Precoder

Computing & Wireless : Wireless and Communications

Available for non-exclusive licensing


  • Robert Heath, Jr., Ph.D. , Electrical and Computer Engineering
  • Insoo Hwang , Samsung Electronics Company, Ltd.
  • Chan-Byoung Chae , University of Texas at Austin
  • Seijoon Shim , Electrical and Computer Engineering
  • Jonghyung Kwun , Samsung Electronics Company, Ltd.

Background/unmet need

Precoding with block diagonalization is an attractive method for approaching sum capacity in multiuser multiple-input multiple-output (MlMO) broadcast channels. This method requires either global channel state information at every receiver or an additional training phase, which demands additional system planning.

Invention Description

We present a hybrid type (linear/non-linear) precoding technique that supports multiple stream transmission in a multiuser broadcast channel. All prior approaches assume a minimum complete and perfect CSI at the transmitter. Using this assumption, our proposed scheme exploits the BD linear precoding algorithm to transmit interference-free groups of data to different users. To avoid the need for a complex receiver, however, we use a ZF prefilter combined with a multi-stream vector perturbation to avoid the corresponding power enhancement.


  • Provides a means to design MIMO precoder and decoder for downlink multiuser transmission.
  • Linear/non-linear signal processing at the transmitter is utilized to guarantee low complexity and low power consumption at the receiver.
  • Improves system throughput and capacity compared with the conventional BD system.
  • Works with advanced communication technologies such as MIMO and OFDM.


  • We do not require global CSI at the receiver or an additional training phase.
  • Our approach has much lower receiver complexity, at the expense of additional transmit complexity over BD.

Market potential/applications

Existing and future cellular systems and wireless LANs with MIMO technology

IP Status

  • 1 foreign patent application filed
  • 1 U.S. patent issued: 8,204,142