Method, apparatus and system for use in the transmission of wireless communications using multiple antennas

• US 20050136841A1
• Filed: 12/23/2003
• Published: 06/23/2005
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Frank, Colin
• Granted Patent: US 7,457,590 B2
• Time in Patent Office: Days
• US Class Current: 455/65
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A method, apparatus and system are provided for use in optimizing signal-to-noise ratios at remote wireless devices. A method can receive a signal over a reverse link, determine an angular power profile of the reverse link signal, and determine an antenna weighting vector for the forward traffic signal based on the angular power profile. The determination of the weighting vector can include retrieving the vector from a weighting vector table. Some methods identify boundaries of angular spreads and utilize pre-calculate weighting vectors according to the boundaries. An apparatus can include an antenna array, a wireless receiver that receives reverse link signals, a detector that detects an angular power profile of the signals, a controller that determines a weighting vector and applies the weighting vector to the antenna array when transmitting. Some embodiments are dependent on whether the forward link incorporates a common pilot or per-user pilot signal.

Claims

1. A method for use in optimizing a signal-to-noise ratio (SNR) at a wireless device receiving wireless communication, comprising:

receiving a reverse link signal over a wireless reverse link channel from the wireless device;

determining an angular power profile of the reverse link signal; and

determining an antenna weighting vector for a forward traffic signal based on the angular power profile of the reverse link signal;

applying the antenna weighting vector; and

transmitting a forward link signal while the antenna weighting is applied.

2. The method of claim 1, wherein determining the antenna weighting vector comprises accessing an antenna weighting vector table, and retrieving the antenna weighting vector that is associated with the determined angular power profile.

3. The method of claim 2, further comprising:

identifying a plurality of boundaries of angular spreads for the reverse link;

pre-calculating a plurality of antenna weighting vectors according to boundaries of the angular spreads; and

incorporating the plurality of pre-calculated antenna weighting vectors into the antenna weighting vector table prior to the retrieving of the antenna weighting vector that is associated with the determined angular power profile.

4. The method of claim 3, further comprising:

determining a first matrix, proportional to the angular power profile and an antenna array response;

determining a second matrix proportional to the first matrix;

selecting an eigenvector from the second matrix; and

wherein

pre-calculating the plurality of antenna weighting vectors comprises pre-calculating at least one of the plurality of pre-calculated antenna weighting vectors based on the eigenvector.

5. The method of claim 3, further comprising:

determining a first matrix that is proportional to an antenna array response;

determining a second matrix which is proportional to the received angular power profile;

determining a pilot weighing vector; and

wherein

pre-calculating the plurality of antenna weighting vectors comprises pre-calculating at least one of the plurality of pre-calculated antenna weighting vectors based on the first and second matrices and the pilot weighting vector.

6. The method of claim 1, further comprising:

determining a first matrix using the received angular power profile;

factoring the first matrix into a product of a Q matrix and a Hermitian of the Q matrix;

determining a third matrix from a product of the inverse of the Hermitian of Q matrix, the first matrix and the inverse of the Q matrix;

determining an eigenvector of the third matrix; and

wherein

determining the antenna weighting vector comprises determining the antenna weighting vector based on the eigenvector.

7. The method of claim 1, further comprising:

determining a pilot weighting vector; and

wherein

determining the antenna weighting vector based on the received angular power profile comprises determining the antenna weighting vector such that the antenna weighting vector is based in part on the pilot weighting vector.

8. The method of claim 1, further comprising:

determining an antenna array response;

determining a first matrix as the integral of a product of outer products of the array response vector;

factoring the first matrix to obtain a Q matrix; and

wherein

determining the antenna weighting vector based on the angular power profile comprises determining the antenna weighting vector such that the antenna weighting vector is based in part on the Q matrix.

9. A method for use in beam generation for wireless communication, comprising:

determining an antenna array response;

determining a first matrix based on the antenna array response;

factoring the first matrix and obtaining a Q matrix;

determining an angular power profile of a received wireless reverse link channel signal; and

determining an antenna weighting vector based on the angular power profile and the Q matrix.

10. The method of claim 9, further comprising:

applying the antenna weighting vector to an antenna array;

generating a forward link signal through the antenna array with the antenna weighting vector applied.

11. The method of claim 9, further comprising:

determining a second matrix that is proportional to the antenna array response and the angular power profile of the reverse link signal;

determining a third matrix proportional to the angular power profile of the reverse link signal and the angular power profile;

calculating a fourth matrix based on the Q matrix and the third matrix; and

wherein

determining the antenna weighting vector comprises the calculating the antenna weighting vector based on the fourth matrix.

12. The method of claim 11, further comprising:

determining a maximum eigenvalue of the fourth matrix;

determining an eigenvector of the fourth matrix associated with the maximum eigenvalue, wherein determining the antenna weighting vector comprises calculating the antenna weighting vector as the product of the inverse of the Q matrix and the eigenvector associated with the maximum eigenvalue.

13. The method of claim 11, wherein determining the third matrix comprises determining an integral of the product of the angular power profile of the reverse link signal and an outer product of the antenna array response.

14. The method of claim 9, further comprising:

determining a plurality of angular boundaries;

pre-calculating a plurality of antenna weighting vectors;

generating a weighting vector table and incorporating the plurality of pre-calculated weighting vectors into the weighting vector table; and

wherein

determining the antenna weighting vector comprises determining a direction and angular spread of reception of the reverse link signal and selecting the antenna weighing vector from the plurality of pre-calculated antenna weighting vectors of the weighting vector table that corresponds with the determined direction and angular spread.

15. The method of claim 14, further comprising:

determining a pilot weighting vector; and

wherein

pre-calculating the plurality of antenna weighting vectors comprises pre-calculating the plurality of antenna weighting vectors based on the pilot weighting vector.

16. The method of claim 14, further comprising:

determining boundaries of angular spread;

defining continuums between the boundaries; and

wherein

pre-calculating the plurality of antenna weighting vectors comprises pre-calculating the plurality of antenna weighting vectors according to the defined continuums.

17. An apparatus for use in providing increased capacity over a wireless communication network, the apparatus comprising:

an antenna array that at least transmits traffic signals;

a wireless receiver that receives a reverse link signal;

a detector coupled with the wireless receiver, wherein the detector detects an angular power profile of the reverse link signal;

a controller coupled with the detector and the antenna array, wherein the controller directs the determination of a weighting vector; and

the controller directs the weighting vector to be applied to the antenna array when transmitting the traffic signal.

18. The apparatus of claim 17, further comprising:

a memory having a weighting vector table coupled with the controller, wherein the controller selects the weighting vector from the weighting vector table that is associated with the angular power profile.

19. The apparatus of claim 18, further comprising:

a computational calculator coupled with the detector, wherein the computational calculator pre-calculates a plurality of weighting vectors; and

the memory couples with the computational calculator, wherein the computational calculator stores the plurality weighting vectors in the weighting vector table.

20. The apparatus of claim 17, further comprising:

a computational calculator coupled with the detector, wherein the computational calculator calculates the weighting vector that is applied to the antenna array when transmitting the traffic signal.