System and method for link adaptation in DIDO multicarrier systems

• US 20110002411A1
• Filed: 06/16/2010
• Published: 01/06/2011
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: Rearden, LLC
• Original Assignee: Rearden, LLC
• Inventors: Forenza, Antonio, Perlman, Stephen G.
• Granted Patent: US 10,886,979 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• CPC Class Codes: H04L 1/0021 in which the algorithm uses adaptive thresholds
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03891 Spatial equalizers MIMO diversity systems H04B7/0413
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

A system and machine-implemented method are described for communicating with a plurality of distributed-input-distributed-output (DIDO) clients. For example, a method according to one embodiment comprises: determining channel state information (CSI) defining a channel state between each of a first plurality of DIDO antennas and each of the DIDO clients; using the CSI to determine distributed-input-distributed-output (DIDO) precoding weights for each of the channels between each of the first plurality of DIDO antennas and the antennas of each of the DIDO clients; using the CSI and DIDO precoding weights to determine link quality metrics defining link quality between each of the first plurality of DIDO antennas and the antennas of each of the DIDO clients; using the link-quality metrics, to determine modulation coding schemes (MCSs) for different DIDO clients; and transmitting precoded data streams from each of the first plurality of DIDO antennas to each of the individual DIDO clients using the determined MCSs for those clients.

Claims

1. A machine-implemented method for communicating with a plurality of distributed-input-distributed-output (DIDO) clients comprising:

determining channel state information (CSI) defining a channel state between each of a first plurality of DIDO antennas and each of the DIDO clients;

using the CSI to determine distributed-input-distributed-output (DIDO) precoding weights for each of the channels between each of the first plurality of DIDO antennas and the antennas of each of the DIDO clients;

using the CSI and DIDO precoding weights to determine link quality metrics defining link quality between each of the first plurality of DIDO antennas and the antennas of each of the DIDO clients;

using the link-quality metrics, to determine modulation coding schemes (MCSs) for different DIDO clients; and

transmitting precoded data streams from each of the first plurality of DIDO antennas to each of the individual DIDO clients using the determined MCSs for those clients.

2. The method as in claim 1 wherein, in a system which employs orthogonal frequency-division multiplexing (OFDM), the link quality metric comprises an average signal to noise ratio over all OFDM tones.

3. The method as in claim 1 wherein the link quality metric is a frequency response of the effective channels between the first plurality of antennas and the antennas of the clients.

4. The method as in claim 1 wherein, in a system which employs orthogonal frequency-division multiplexing (OFDM), the method further comprising:

based on the link-quality metrics, determining the different OFDM tones to be used to communicate with each of the different DIDO clients.

5. The method as in claim 1 further comprising:

transmitting an indication of the MCSs to be used for communication to each of the respective DIDO clients.

6. The method as in claim 5 wherein, in a system which employs orthogonal frequency-division multiplexing (OFDM), the method further comprising:

transmitting an indication of the different tones to be used for communication to each of the respective DIDO clients.

7. The method as in claim 1 further comprising adjusting the MCSs based on detected temporal variations of channel gain.

8. The method as in claim 1 wherein the MCSs are recalculated every fraction of channel coherence time.

9. The method as in claim 1 further comprising implementing DIDO precoding with inter-DIDO-cluster interference (IDCI) cancellation to transmit from the first plurality of DIDO antennas and create zero RF energy at the location of the first DIDO client.

16. The method as in claim 11 further comprising transmitting from M distributed DIDO antennas to create up to (M−

1) points of zero RF energy.

17. The method as in claim 15 wherein the wherein the DIDO antennas are aware of the channel state information between the transmitters and the receivers, and the transmitters utilize the channel state information to determine interfering signals to be simultaneously transmitted.

18. The method as in claim 17 using block diagonalization precoding.

19. The method as in claim 18 wherein the locations with zero RF energy correspond to the location of each of the DIDO clients and DIDO precoding is used to create points of zero RF energy to the clients.

20. The method as in claim 19 wherein points of zero RF energy are created to remove interference between adjacent DIDO clusters.