Method for minimizing cross-talk in adaptive transmission antennas
First Claim
1. A method for minimizing cross-talk among information signals in a wireless communication system comprising an array of transmitting elements and a collection of receivers, the method comprising the steps of:
- transmitting a set of probing signals from the array according to a probing weight matrix;
feeding back from the receivers to the array in response to the probing signals a set of feedback signals measuring the cross-talk;
calculating from the feedback signals a new weight matrix that reduces the cross-talk measured by the feedback signals; and
transmitting a set of new information signals according to the new weight matrix.
1 Assignment
0 Petitions
Accused Products
Abstract
A method is disclosed for using feedback signals (32) to optimize the directional properties of information signals (19) with respect to their intended receivers (16), where information signals (19) are applied to the transmitting elements (14) of a transmitting antenna array (12). Feedback signals (32) generated at receivers (16) by probing signals (17) are monitored, and the weight matrix with which signals (17) are distributed among array elements (14) is adjusted according to feedback signals (32) to minimize cross-talk. Information signals (18) transmitted according to an optimized weight matrix will also have reduced cross-talk. A weight matrix may be optimized by perturbing an initial weight matrix, calculating an error function from the feedback signals (32) produced by each perturbed weight matrix, estimating the direction of an extremum from the error functions, and adjusting the initial weight matrix in that direction. Alternatively, a gain matrix for the transmitting array may be explicitly determined by sequentially exciting each transmitting element (14) and measuring the resultant feedback signals (32). These are then used to calculate the weight matrix that eliminates cross-talk.
216 Citations
18 Claims
-
1. A method for minimizing cross-talk among information signals in a wireless communication system comprising an array of transmitting elements and a collection of receivers, the method comprising the steps of:
-
transmitting a set of probing signals from the array according to a probing weight matrix; feeding back from the receivers to the array in response to the probing signals a set of feedback signals measuring the cross-talk; calculating from the feedback signals a new weight matrix that reduces the cross-talk measured by the feedback signals; and transmitting a set of new information signals according to the new weight matrix. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method for using feedback and spatial multiplexing to reduce cross-talk between information signals transmitted from an array of transmitting elements to a collection of receivers, the method comprising the steps of:
-
choosing a weight matrix W which characterizes the complex amplitudes with which the information signals are applied to the array of transmitting elements; transmitting the information signals from the array to the receivers according to the weight matrix W; feeding back from the receivers to the array a signal matrix C whose off-diagonal elements measure the cross-talk between the information signals; calculating a new weight matrix W'"'"' from the weight matrix W and the signal matrix C such that a formula equivalent to W'"'"'=W(C-1)H is substantially satisfied; and transmitting new information signals from the array according to the new weight matrix W'"'"'. - View Dependent Claims (13, 14, 15, 16, 17, 18)
-
Specification