Interference management, handoff, power control and link adaptation in distributed-input distributed-output (DIDO) communication systems

Patent metadata

Field	Value
Publication number	US-10200094-B2
Application number	US-80298810-A
Country	US
Kind code	B2
Filing date	Jun 16, 2010
Priority date	Apr 2, 2004
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A system and method are described herein employing a plurality of distributed transmitting antennas to create locations in space with zero RF energy. In one embodiment, when M transmit antennas are employed, it is possible to create up to (M−1) points of zero RF energy in predefined locations. In one embodiment of the invention, the points of zero RF energy are wireless devices and the transmit antennas are aware of the channel state information (CSI) between the transmitters and the receivers. In one embodiment, the CSI is computed at the receivers and fed back to the transmitters. In another embodiment, the CSI is computed at the transmitter via training from the receivers, assuming channel reciprocity is exploited. The transmitters may utilize the CSI to determine the interfering signals to be simultaneously transmitted. In one embodiment, block diagonalization (BD) precoding is employed at the transmit antennas to generate points of zero RF energy.

First claim

The invention claimed is:

1. A multiuser (MU) multiple antenna system (MU-MAS) comprising:
one or more centralized units communicatively coupled to a plurality of distributed wireless transceivers via a network;
the network carrying baseband or radio frequency (RF) signals; and
one or a plurality of precoding units that generate a plurality of precoded waveforms;
wherein the distributed wireless transceivers comprise baseband or RF units to transform the precoded waveforms into a plurality of RF signals and cooperate to coordinate the transmission of the RF signals to jointly create a plurality of concurrent locations in space with zero RF energy;
the system further comprising:
a main MU-MAS cluster having at least one base transceiver station (BTS) connected to a first plurality of antennas for communicating with a target user, wherein the BTSs in the main MU-MAS cluster implement MU-MAS precoding to transmit simultaneous non-interfering data streams within the same frequency band to a first plurality of MU-MAS users including the target user; and
one or more interfering MU-MAS clusters, each interfering MU-MAS cluster having at least one BTS connected to a second plurality of antennas communicating with a second plurality of MU-MAS users, wherein the BTSs in the interfering MU-MAS cluster implement MU-MAS precoding to transmit simultaneous non-interfering data streams within the same frequency band to the second plurality of MU-MAS users;
wherein when the target user is located within a zone in which the target user is transmitting and receiving data streams to and from the antennas in the main MU-MAS cluster, respectively, and is also detecting RF signals transmitted from the antennas in the interfering MU-MAS cluster, the BTSs in the interfering MU-MAS cluster implement MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation to avoid RF interference at the target user.

2. The system as in claim 1 wherein implementing MU-MAS precoding with IMCI cancellation comprises creating zero RF energy towards the direction of the target user.

3. The system as in claim 1 wherein the BTSs in the main MU-MAS cluster compute MU-MAS precoding weights to pre-cancel inter-user interference with the first plurality of MU-MAS users in the main MU-MAS cluster.

4. The system as in claim 3 wherein the BTSs in the main MU-MAS cluster implement block diagonalization (BD) precoding to pre-cancel the inter-user interference with the first plurality of MU-MAS users.

5. The system as in claim 1 wherein the BTSs in the interfering MU-MAS cluster compute MU-MAS precoding weights to pre-cancel inter-user interference with second plurality of MU-MAS users serviced by the interfering MU-MAS cluster and compute additional MU-MAS precoding weights for IMCI cancellation to avoid RF interference at the target user.

6. The system as in claim 5 wherein the BTSs in the interfering MU-MAS cluster implement block diagonalization (BD) precoding to both pre-cancel the inter-user interference with the second plurality of MU-MAS users and to perform IMCI cancellation to avoid RF interference at the target user.

7. The system as in claim 1 wherein the BTSs in the interfering MU-MAS cluster implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the target user only if the signal-to-interference ratio (SIR) computed from signal strength detected by the target user from the main MU-MAS cluster and interference signal strength detected by the target user from the interfering MU-MAS cluster is below a specified threshold.

8. A machine-implemented method within a multiuser (MU) multiple antenna system (MU-MAS) comprising:
communicatively coupling one or more centralized units to a plurality of distributed wireless transceivers via a network, the network carrying baseband or radio frequency (RF) signals;
generating a plurality of precoded waveforms from one or a plurality of precoding uinits;
the distributed wireless transceivers comprising baseband or radio frequency (RF) units to transform the precoded waveforms into a plurality of radio frequency (RF) signals and cooperating to coordinate the transmission of the RF signals to jointly create a plurality of concurrent locations in space with zero RF energy;
the method further comprising:
associating a target user with a main MU-MAS cluster having at least one base transceiver station (BTS) connected to a first plurality of antennas,
implementing MU-MAS precoding on the BTSs in the main MU-MAS cluster to transmit simultaneous non-interfering data streams within the same frequency band to a first plurality of MU-MAS users including the target user;
associating a second plurality of MU-MAS users with an interfering MU-MAS cluster having at least one BTS connected to a second plurality of antennas;
implementing MU-MAS precoding on the BTSs in the interfering MU-MAS cluster to transmit simultaneous non-interfering data streams within the same frequency band to a second plurality of MU-MAS users; and
implementing MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation at the BTSs in the interfering MU-MAS cluster to avoid RF interference at the target user if the target user is located within a zone in which the target user is transmitting and receiving data streams to and from the antennas in the main MU-MAS cluster, respectively, and is also detecting RF signals transmitted from the antennas in the interfering MU-MAS cluster.

9. The method as in claim 8 wherein implementing MU-MAS precoding with IMCI cancellation comprises creating zero RF energy towards the direction of the target user.

10. The method as in claim 8 wherein the BTSs in the main MU-MAS cluster compute MU-MAS precoding weights to pre-cancel inter-interference with the first plurality of MU-MAS users in the main MU-MAS cluster.

11. The method as in claim 10 wherein the BTSs in the main MU-MAS cluster implement block diagonalization (BD) precoding to pre-cancel the inter-user interference with the first plurality of MU-MAS users.

12. The method as in claim 8 wherein the BTSs in the interfering MU-MAS cluster compute MU-MAS precoding weights to pre-cancel inter-user interference with second plurality of MU-MAS users serviced by the interfering MU-MAS cluster and compute additional MU-MAS precoding weights for IMCI cancellation to avoid RF interference at the target user.

13. The method as in claim 12 wherein the BTSs in the interfering MU-MAS cluster implement block diagonalization (BD) precoding to both pre-cancel the inter-user interference with the second plurality of MU-MAS users and to perform IMCI cancellation to avoid RF interference at the target user.

14. The method as in claim 8 wherein the BTSs in the interfering MU-MAS cluster implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the target user only if the signal-to-interference ratio (SIR) computed from signal strength detected by the target user from the main MU-MAS cluster and interference signal strength detected by the target user from the interfering MU-MAS cluster is below a specified threshold.

Assignees

• Forenza Antonio
• Perlman Stephen G
• Rearden Llc

Inventors

• Forenza Antonio
• Perlman Stephen G

Classifications

• Y02D70/164

  Cross-Sectional Technologies · mapped topic

• Y02D70/22

  Cross-Sectional Technologies · mapped topic

• Y02D70/146

  Cross-Sectional Technologies · mapped topic

• Y02D70/1262

  Cross-Sectional Technologies · mapped topic

• H04B7/0626

  Channel coefficients, e.g. channel state information [CSI] · CPC title