Method of determining the direction of arrival of a radio signal, as well as radio base station and radiocommunications system

Claim 3

A method as claimed in claim 1, wherein said first vector, which is to correspond to said required eigenvector, is determined by reading contents of a first column of said matrix (A).

Claim 4

A method as claimed in claim 1, wherein the step of computing a required eigenvector further comprises the part step of: c) determining a maximum (d) of the components of said product vector (A·W i ), and computing a new vector (W i+1 ) by weighting said product vector (A·W i ) with the inverse of said maximum (i.e., W i+1 =(1/d)·A·W i ).

Claim 5

A method as claimed in claim 3, wherein said part steps b) and c) are iteratively repeated until said Rayleigh quotient changes by less than a predeterminable tolerance value.

Claim 6

A method as claimed in claim 3, wherein said part steps b) and c) are iteratively repeated until a predetermined number of cycles is reached.

Claim 7

A method as claimed in claim 1, further comprising the step of evaluating said last computed vector to determine a direction of transmission by weighting said last computed vector with a weight factor, wherein said weight factor is determined from an offset between a transmitted frequency and a received frequency.

Claim 8

A radio base station comprising: an antenna array having at least two radiating elements for receiving a radio signal distorted by multipath; an evaluating device connected to said antenna array, wherein said evaluating device collects data for each of said at least two radiating elements, and wherein said data specify a receive level and a phase position for determining a direction of arrival of said radio signal; and a memory device, connected to said evaluating device, for storing said data in the form of a symmetrical matrix (A) having M columns and M rows; wherein said evaluating device computes an eigenvector corresponding to a dominant eigenvalue of said symmetrical matrix (A) in the following manner: a) setting a counter (i) to 1 (i=1) and estimating a first vector (W i , with i=1), which is to correspond to said eigenvector, for said dominant eigenvalue of said matrix (A); and b) computing an ith product vector (A·W i ) from said matrix (A) and said first vector (W i ), and computing a Rayleigh quotient (RQ) from the formula: RQ=(A·W.sub.i ·W.sub.i)/(W.sub.i ·W.sub.i); wherein said radio base station points a radiation pattern of said antenna array by evaluating a last computed vector (W i=n ), which is said eigenvector, and wherein said eigenvector indicates said direction of arrival of a strongest radio signal.

Claim 9

A radio base station comprising: an antenna array having at least two radiating elements for receiving a radio signal distorted by multipath; an evaluating device connected to said antenna array, wherein said evaluating device collects data for each of said at least two radiating elements, and wherein said data specify a receive level and a phase position for determining a direction of arrival of said radio signal; and a memory device, connected to said evaluating device, for storing said data in the form of a symmetrical matrix (A) having M columns and M rows; wherein said evaluating device computes an eigenvector corresponding to a dominant eigenvalue of said symmetrical matrix (A) in the following manner: a) setting a counter (i) to 1 (i=1) and estimating a first vector (W i , with i=1), which is to correspond to said eigenvector, for said dominant eigenvalue of said matrix (A); and b) computing an ith product vector (A·W i ) from said matrix (A) and said first vector (W i ), and computing a Rayleigh quotient (RQ) from the formula: RQ=(A·W.sub.i ·W.sub.i)/(W.sub.i ·W.sub.i); wherein said radio base station points a radiation pattern of said antenna array by evaluating a last computed vector (W i=n ), which is said eigenvector, and wherein said eigenvector indicates said direction of arrival of a strongest radio signal.

Claim 10

A radio base station as claimed in claim 7, wherein said evaluating device computes said eigenvector by further determining a maximum (d) of the components of said product vector (A·W i ), and computing a new vector (W i+1 ) by weighting said product vector (A·W i ) with the inverse of said maximum (i.e., W i+1 =(1/d)·A·W i ).

Claim 11

A radiocommunications system comprising at least one radio base station, wherein said at least one radio base station comprises: an antenna array having at least two radiating elements for receiving a radio signal distorted by multipath; an evaluating device connected to said antenna array, wherein said evaluating device collects data for each of said at least two radiating elements, and wherein said data specify a receive level and a phase position for determining a direction of arrival of said radio signal; and a memory device, connected to said evaluating device, for storing said data in the form of a symmetrical matrix (A) having M columns and M rows; wherein said evaluating device computes an eigenvector corresponding to a dominant eigenvalue of said symmetrical matrix (A) in the following manner: a) setting a counter (i) to 1(i=1) and estimating a first vector (W i , with i=1), which is to correspond to said eigenvector, for said dominant eigenvalue of said matrix (A); and b) computing an ith product vector (A·W i ) from said matrix (A) and said first vector (W i ), and computing a Rayleigh quotient (RQ) from the formula: RQ=(A·W.sub.i ·W.sub.i)/(W.sub.i ·W.sub.i); wherein said at least one radio base station points a radiation pattern of said antenna array by evaluating a last computed vector (W i=1 ), which is said eigenvector, and wherein said eigenvector indicates said direction of arrival of a strongest radio signal.

Claim 12

A radiocommunications system comprising at least one radio base station, wherein said at least one radio base station comprises: an antenna array having at least two radiating elements for receiving a radio signal distorted by multipath; an evaluating device connected to said antenna array, wherein said evaluating device collects data for each of said at least two radiating elements, and wherein said data specify a receive level and a phase position for determining a direction of arrival of said radio signal; and a memory device, connected to said evaluating device, for storing said data in the form of a symmetrical matrix (A) having M columns and M rows; wherein said evaluating device computes an eigenvector corresponding to a dominant eigenvalue of said symmetrical matrix (A) in the following manner: a) setting a counter (i) to 1(i=1) and estimating a first vector (W i , with i=1), which is to correspond to said eigenvector, for said dominant eigenvalue of said matrix (A); and b) computing an ith product vector (A·W i ) from said matrix (A) and said first vector (W i ), and computing a Rayleigh quotient (RQ) from the formula: RQ=(A·W.sub.i ·W.sub.i)/(W.sub.i ·W.sub.i); wherein said at least one radio base station points a radiation pattern of said antenna array by evaluating a last computed vector (W i=1 ), which is said eigenvector, and wherein said eigenvector indicates said direction of arrival of a strongest radio signal.

Claim 13

A radiocommunications system as claimed in claim 9, wherein said evaluating device computes said eigenvector by further determining a maximum (d) of the components of said product vector (A·W i ), and computing a new vector (W i+1 ) by weighting said product vector (A·W i ) with the inverse of said maximum (i.e., W i+1 =(1/d)·A·W i ).