System and method for managing inter-cluster handoff of clients which traverse multiple DIDO clusters

• US 9,826,537 B2
• Filed: 06/16/2010
• Issued: 11/21/2017
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: Rearden, LLC
• Original Assignee: Rearden, LLC
• Inventors: Forenza, Antonio, Perlman, Stephen G.
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): MCKIE, GINA M
• Application Number:
  US12/802,974
• Publication Number:
  US 20110003606A1
• Time in Patent Office: 2,715 Days
• Field of Search: None
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/0417 Feedback systems
• 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 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• 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 72/542 using measured or perceived quality

Abstract

A system and method are described for adjusting communication with a first distributed-input-distributed-output (DIDO) client as the first DIDO client moves from a first DIDO cluster to a second DIDO cluster: For example, in one embodiment of the system and method, different signal strength thresholds are specified and either conventional DIDO precoding and/or DIDO precoding with inter-DIDO-cluster interference (IDCI) cancellation to avoid RF interference at the DIDO client are employed based on measured signal strengths from a main DIDO cluster and an interfering DIDO cluster.

Claims

1. A machine-implemented method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative, distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2;

wherein, when the first client is within a zone in which S2 is sufficiently low with respect to S1, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the first MU-MAS cluster to transmit a first set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client, and MU-MAS precoding without IMCI cancellation is implemented a BTS in the second MU-MAS cluster to transmit a second set of simultaneous non-interfering data streams within the frequency band to a second plurality of clients not including the first client.

2. The method as in claim 1, further comprising:

calculating a signal-to-interference-plus-noise ratio (SINR) or signal-to-interference ratio (SIR) for S1 and S2; and

defining one or more of the signal thresholds based on values of the SIR or SINR.

3. The method as in claim 1, further comprising:

adjusting one or more of the threshold values dynamically to implement a hysteresis loop in response to the first client moving between zones to avoid repetitive switches between each of the zones based on the relative values of S1 and S2.

4. The method as in claim 1, wherein a determination as to the zone in which the client currently resides is made by the client.

5. The method as in claim 1, wherein a determination as to a zone in which the client currently resides is made by a base transceiver station (BTS) in the first MU-MAS cluster or the second MU-MAS cluster.

6. The method as in claim 1, wherein the switching is implemented with a finite state machine, the finite state machine implemented as a processor executing sequences of instructions.

7. The method as in claim 1 wherein implementing MU-MAS precoding with IMCI cancellation comprises transmitting a plurality of radio frequency (RF) signals to create locations in space with zero RF energy.

8. The method as in claim 7, wherein M distributed transmitting antennas create up to (M−

1) points of zero RF energy.

9. The method as in claim 7, wherein the locations of zero RF energy are receivers, the transmitting antennas are aware of the channel state information between the transmitters and the receivers, and the transmitters utilize the channel state information to determine the interfering signals to be simultaneously transmitted.

10. The method as in claim 9, wherein the MU-MAS precoding is block diagonalization precoding.

11. The method as in claim 1, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a first of the one or more thresholds being reached, the method further comprising:

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the second MU-MAS cluster, wherein a BTS of the second MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

12. The method as in claim 1, wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a second of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client and the method further comprising:

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the first MU-MAS cluster, wherein a BTS of the first MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

13. The method as in claim 1, wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a third of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a first set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client, and MU-MAS precoding without IMCI cancellation is implemented on a BTS in the first MU-MAS cluster to transmit a second set of simultaneous non-interfering data streams within the frequency band to a second plurality of clients not including the first client.

14. A system comprising a processing device and a memory storing instructions, wherein the processing device executes the instructions that cause the system to perform a method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2;

wherein, when the first client is within a zone in which S2 is sufficiently low with respect to S1, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the first MU-MAS cluster to transmit a first set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client, and MU-MAS precoding without IMCI cancellation is implemented a BTS in the second MU-MAS cluster to transmit a second set of simultaneous non-interfering data streams within the frequency band to a second plurality of clients not including the first client.

15. The system as in claim 14, the method further comprising:

calculating a signal-to-interference-plus-noise ratio (SINR) or signal-to-interference ratio (SIR) for S1 and S2; and

defining one or more of the signal thresholds based on values of the SIR or SINR.

16. The system as in claim 14, the method further comprising:

adjusting one or more of the threshold values dynamically to implement a hysteresis loop in response to the first client moving between zones to avoid repetitive switches between each of the zones based on the relative values of S1 and S2.

17. The system as in claim 14, the method wherein a determination as to the zone in which the client currently resides is made by the client.

18. The system as in claim 14, the method wherein a determination as to a zone in which the client currently resides is made by a base transceiver station (BTS) in the first MU-MAS cluster or the second MU-MAS cluster.

19. The system as in claim 14, wherein the switching is implemented with a finite state machine, the finite state machine implemented as a processor executing sequences of instructions.

20. The system as in claim 14 wherein implementing MU-MAS precoding with IMCI cancellation comprises transmitting a plurality of radio frequency (RF) signals to create locations in space with zero RF energy.

21. The system as in claim 20, wherein M distributed transmitting antennas create up to (M−

1) points of zero RF energy.

22. The system as in claim 20, wherein the locations of zero RF energy are receivers, the transmitting antennas are aware of the channel state information between the transmitters and the receivers, and the transmitters utilize the channel state information to determine the interfering signals to be simultaneously transmitted.

23. The system as in claim 22, wherein the MU-MAS precoding is block diagonalization precoding.

24. The system as in claim 14, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a first of the one or more thresholds being reached, the method further comprising:

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the second MU-MAS cluster, wherein a BTS of the second MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

25. The system as in claim 14, wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a second of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client and the method further comprising:

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the first MU-MAS cluster, wherein a BTS of the first MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

26. The system as in claim 14, wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a third of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a first set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client, and MU-MAS precoding without IMCI cancellation is implemented on a BTS in the first MU-MAS cluster to transmit a second set of simultaneous non-interfering data streams within the frequency band to a second plurality of clients not including the first client.

27. A machine-implemented method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative, distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2

wherein when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a first of the one or more thresholds being reached, the method further comprising;

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the second MU-MAS cluster, wherein a BTS of the second MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

28. A machine-implemented method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative, distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2;

wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a second of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client and the method further comprising;

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the first MU-MAS cluster, wherein a BTS of the first MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

29. A machine-implemented method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative, distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2;

wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a third of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a first set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client, and MU-MAS precoding without IMCI cancellation is implemented on a BTS in the first MU-MAS cluster to transmit a second set of simultaneous non-interfering data streams within the frequency band to a second plurality of clients not including the first client.

30. A system comprising a processing device and a memory storing instructions, wherein the processing device executes the instructions that cause the system to perform a method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2;

wherein when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a first of the one or more thresholds being reached, the method further comprising;

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the second MU-MAS cluster, wherein a BTS of the second MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

31. A system comprising a processing device and a memory storing instructions, wherein the processing device executes the instructions that cause the system to perform a method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2;

wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a second of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client and the method further comprising;

generating channel state information (CSI) defining a channel state between one or more antennas of the first client and one or more antennas of the first MU-MAS cluster, wherein a BTS of the first MU-MAS cluster uses the CSI to implement MU-MAS precoding with IMCI cancellation to avoid RF interference at the first client.

32. A system comprising a processing device and a memory storing instructions, wherein the processing device executes the instructions that cause the system to perform a method within a multiuser multiple antenna system (MU-MAS), that creates a plurality of simultaneous non-interfering data streams from a plurality of cooperative distributed antennas to a plurality of clients, for adjusting communication with a first client as the first client moves from a first MU-MAS cluster to a second MU-MAS cluster, the method comprising:

detecting signal strength between the first client and the first MU-MAS cluster (“

S1”

) and between the first client and the second MU-MAS cluster (“

S2”

); and

switching between MU-MAS precoding with inter-MU-MAS-cluster interference (IMCI) cancellation and MU-MAS precoding without IMCI cancellation at the first MU-MAS cluster or at the second MU-MAS cluster based upon one or more signal thresholds and the detected signal strengths S1 and S2;

wherein, when the first client is within a zone in which S2 has increased relative to S1 or S1 has decreased relative to S2 such that the relative values of S2 and S1 have resulted in a third of the one or more thresholds being reached, MU-MAS precoding without IMCI cancellation is implemented on a BTS in the second MU-MAS cluster to transmit a first set of simultaneous non-interfering data streams within a frequency band to a first plurality of clients including the first client, and MU-MAS precoding without IMCI cancellation is implemented on a BTS in the first MU-MAS cluster to transmit a second set of simultaneous non-interfering data streams within the frequency band to a second plurality of clients not including the first client.