Closed loop feedback system for improved down link performance

• US 7,844,010 B2
• Filed: 03/02/2005
• Issued: 11/30/2010
• Est. Priority Date: 06/02/2000
• Status: Expired due to Term

• Current Assignee: Intellectual Ventures I LLC (Intellectual Ventures LLC)
• Original Assignee: Spyder Navigations LLC (Intellectual Ventures LLC)
• Inventors: Ylitalo, Juha, Katz, Marcos
• Primary Examiner(s): Bocure; Tesfaldet
• Assistant Examiner(s): Williams; Lawrence B
• Application Number:
  US11/068,855
• Publication Number:
  US 20050157683A1
• Time in Patent Office: 2,099 Days
• Field of Search: 375235-236, 375/267, 375/299, 375/358, 375366-368, 375/273, 375/279, 375/308, 375/329, 375/269, 370/317, 370/334, 370/327, 455/25, 455/101, 455/67.1, 455/103, 455/69, 455/562.1, 455/33.3, 455/104, 455/107, 342/173, 342/174, 342/372
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0652 Feedback error handling
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A method includes receiving at least two space-time coded signals from an antenna system associated with a first station, determining complex channel state information based on the received space-time coded signals, and sending the complex channel state information to the first station. In an alternative embodiment, a method includes transmitting at least two space-time coded signals in respective beams of a multi-beam antenna array, measuring a channel impulse response for each space-time coded signal at a second station, and sending an indicia of a selected set of least attenuated signals from the second station to the first station. The multi-beam antenna array is associated with a first station. The beams transmit a signature code embedded in each respective space-time coded signal, and the signature codes are orthogonal so that the second station can separate and measure the channel impulse response corresponding to each space-time coded signal.

Claims

1. A method comprising:

receiving from a first station at a second station at least two space-time coded signals in respective formed beams of a multi-beam antenna array associated with the first station, the beams having a signature code embedded in each respective space-time coded signal, the signature codes being orthogonal so that the second station separates and measures a channel impulse response corresponding to each space-time coded signal;

measuring the channel impulse response for each space-time coded signal at the second station;

determining, from the received space-time coded signals, a selected set of least attenuated signals and a remaining set of most attenuated signals at the second station; and

sending an indicia of the selected set of least attenuated signals from the second station to the first station, wherein the indicia is for in part re-forming the formed beams.

2. The method of claim 1, wherein the indicia sent from the second station determines which at least two beams are subsequently transmitted from the first station.

3. The method of claim 2, further including receiving the at least two space-time coded signals in the selected at least two beams.

4. The method of claim 3, further including determining, at the second station, complex channel state information based on the received space-time coded signals.

5. The method of claim 4, further including sending the determined complex channel state information to the first station.

6. The method of claim 4, wherein the determined complex channel state information includes at least one weight.

7. The method of claim 6, wherein each weight includes amplitude and phase angle information.

15. The method of claim 2, wherein the at least two beams are each formed using at least two of antenna elements of the multi-beam antenna array.

8. A system comprising a base station and a remote station wherein:

the base station includes a multi-beam antenna array and a transmitter to transmit at least two space-time coded signals in respective formed beams of the multi-beam antenna array, the beams transmitting a signature code embedded in each respective space-time coded signal, the signature codes being substantially orthogonal so that the remote station separates and measures a channel impulse response corresponding to each space-time coded signal;

the remote station includes a receiver and a processor to measure the channel impulse response for each space-time coded signal, and determines, from the received space-time coded signals, a selected set of least attenuated signals and a remaining set of most attenuated signals; and

the remote station further includes a transmitter to send an indicia of the selected set of least attenuated signals from the remote station to the base station, wherein the indicia is for in part re-forming the formed beams.

9. The system of claim 8, wherein the base station includes a processor to select at least two beams for transmission from the base station based on the indicia received from the remote station.

10. The system of claim 9, wherein the base station further includes circuitry to transmit the at least two space-time coded signals in the selected at least two beams.

11. The system of claim 10, wherein the processor of the remote station includes circuitry to determine complex channel state information based on the received space-time coded signals.

12. The system of claim 11, wherein the transmitter of the remote station includes circuitry to send the determined complex channel state information to the base station.

13. The system of claim 11, wherein the determined complex channel state information includes at least one weight.

14. The system of claim 13, wherein each weight includes amplitude and phase angle information.

16. The system of claim 9, wherein the at least two beams are each formed using at least two of antenna elements of the multi-beam antenna array.