US 6,615,024 B1 · Method and apparatus for determining signatures for calibrating a communication station having an antenna array

Abstract

A method and apparatus for estimating the downlink signature for a remote transceiver which is part of a wireless communication system that includes a main transceiver for communicating with the remote transceiver. The main transceiver includes an array of transmit antenna elements. The method uses the remote transceiver for receiving signals when the main transceiver transmits downlink calibration signals. When the main transceiver also has a receive antenna array, the remote transceiver can transmit uplink calibration signals to the main transceiver for determining an uplink signature. The downlink and uplink signatures are used to determine a calibration function to account for differences in the apparatus chains that include the antenna elements of the arrays, and that enable downlink smart antenna processing weights to be determined from uplink smart antenna processing weights when the main transceiver includes means for smart antenna processing according to weights.

Claims60

Dependent claims

In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of antenna elements of a transmit antenna array of the main transceiver to a remote transceiver, wherein the set of downlink calibration waveforms comprise modulated constant modulus calibration signals selected so that the dot product of any two calibration signals transmitted from any two distinct antenna elements of the transmit array is a pure tone;
(b) processing the signals received at the remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to the downlink signature for the remote transceiver, wherein the downlink signature related signals are determined in relation to a reference antenna element of the transmit antenna array;
(c) transmitting the downlink signature related signals from the remote transceiver to the main transceiver;
and
(d) determining the downlink signature of the remote transceiver from the downlink signature related signals received at the main transceiver.

2 more elements

In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of transmit antenna elements of a transmit antenna array of the main transceiver to a plurality of remote transceivers;
(b) processing the signals received at each remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to the downlink signature for each remote transceiver;
(c) transmitting the downlink signature related signals from each remote transceiver to the main transceiver;
(d) determining a downlink signature for each remote transceiver from the downlink signature related signals received at the main transceiver from each remote transceiver;
(e) combining the downlink signatures for each remote transceiver to determine a combined downlink signature,
(f) transmitting a set of one or more uplink calibration waveforms from each remote transceiver to the main transceiver;
(g) processing at the main transceiver the received antenna signals corresponding to the uplink calibration signals transmitted from each remote transceiver, the processing determining an uplink signature for each remote transceiver;
(h) combining the uplink signatures for the remote transceivers to determine a combined uplink signature;
(i) determining a calibration function for the main transceiver from the combined uplink and combined downlink signatures;
and
(j) transmitting from each remote transceiver a remote transceiver received signal quality estimate to the main transceiver,
wherein the signature combining is a weighted combining, the weighting of the signature for each remote transceiver being the remote transceiver signal quality estimate of the remote transceiver.

9 more elements

A wireless communication system comprising:

(a) a main transceiver comprising:
(i) an array of transmit antenna elements,
(ii) one or more receive antenna elements, and
(iii) one or more main transceiver signal processors for processing received antenna signals and for forming transmit apparatus signals;
and
(b) a remote transceiver capable of receiving signals from and transmitting signals to the main transceiver comprising:
(i) a remote transceiver receive antenna for receiving remote transceiver received signals,
(i) a remote transceiver transmit antenna for transmitting remote transceiver transmit signals to the main transceiver, and
(iii) one or more remote transceiver signal processors for processing remote transceiver received signals and for forming remote transceiver transmit signals,
wherein at least one of the main transceiver signal processors is programmed to:
transmit a set of downlink calibration waveforms from the main transceiver via the transmit antenna array to the remote transceiver, wherein the downlink calibration waveforms comprise modulated constant modulus calibration signals selected so that the dot product of any two calibration signals transmitted from any two distinct antenna elements of the transmit array is a pure tone;
wherein at least one of the remote transceiver signal processors is programmed to:
process the signals received corresponding to the transmitted downlink calibration waveforms at the remote transceiver to determine downlink signature related signals related to the downlink signature for the remote transceiver, wherein the downlink signature is determined in relation to a reference antenna element of the transmit antenna array;
transmit the downlink signature related signals from the remote transceiver to the main transceiver, and
wherein at least one of the main transceiver signal processors is programmed to:
process the downlink signature related signals received at the main transceiver from the remote transceiver to determine the downlink signature for the remote transceiver.

13 more elements

In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of antenna elements of a transmit antenna array of the main transceiver to a remote transceiver, wherein the downlink calibration waveforms comprise combinations of M distinct modulated constant modulus calibration signals, M being the number of antenna elements of the antenna array for which a downlink signature is being determined, each calibration signal comprising two segments, denoted a first segment and a second segment, respectively, the two segments being identically timed for each calibration signal, wherein during the first segment time interval, a first set of linear combinations of the calibration signals is transmitted from each of the antenna elements of the transmit array, and during the second segment time interval, a second set of linear combinations of the calibration signals is transmitted from each of the antenna elements of the transmit array;
(b) processing the signals received at the remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to the downlink signature for the remote transceiver;
(c) transmitting the downlink signature related signals from the remote transceiver to the main transceiver;
and
(d) determining the downlink signature of the remote transceiver from the downlink signature related signals received at the main transceiver.

2 more elements

A wireless communication system comprising:

(a) a main transceiver comprising:
(i) an array of transmit antenna elements,
(ii) one or more receive antenna elements, and
(iii) one or more main transceiver signal processors for processing received antenna signals and for forming transmit apparatus signals;
and
(b) a remote transceiver capable of receiving signals from and transmitting signals to the main transceiver comprising:
(i) a remote transceiver receive antenna for receiving remote transceiver received signals,
(i) a remote transceiver transmit antenna for transmitting remote transceiver transmit signals to the main transceiver, and
(iii) one or more remote transceiver signal processors for processing remote transceiver received signals;
and for forming remote transceiver transmit signals,
wherein at least one of the main transceiver signal processors is programmed to:
transmit a set of downlink calibration waveforms from the main transceiver via the transmit antenna array to the remote transceiver,
wherein at least one of the remote transceiver signal processors is programmed to:
process the signals received corresponding to the transmitted downlink calibration waveforms at the remote transceiver to determine downlink signature related signals related to the downlink signature for the remote transceiver wherein the downlink signature related waveforms are determined in relation to a reference antenna element by:
cross correlating the signals received at the remote transceiver with each of the tone signals, and normalizing the correlations with the signal transmitted from the reference antenna element;
transmit the downlink signature related signals from the remote transceiver to the main transceiver, and
wherein at least one of the main transceiver signal processors is programmed to:
process the downlink signatures related at the main transceiver from the remote transceiver to determine the downlink signature for the remote transceiver.

15 more elements

Dependencies are inferred from the claim text.

Method and apparatus for determining signatures for calibrating a communication station having an antenna array

Life of this patent

Method and apparatus for determining signatures for calibrating a communication station having an antenna array

Life of this patent

Abstract

Claims60