Antenna signal processing systems
First Claim
1. A signal processing system for determining weights for an adaptive antenna, the antenna having a plurality of antenna elements each for receiving a signal comprising a plurality of subcarriers, the system comprising:
- a plurality of inputs for receiving signals from said plurality of antenna elements;
a time-to-frequency domain transformer for each input for transforming the signal from each input to a plurality of subcarrier signals;
a first weight determiner coupled to said inputs, before the time-to-frequency domain transformer in the signal path, and configured to determine a first set of weights, one for each input; and
a second weight determiner coupled to said first weight determiner and configured to determine, from the determination of said first set of weights, at least one second set of weights comprising a frequency-domain weight for a subcarrier signal derived from each of said inputs.
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Accused Products
Abstract
This invention relates to improved antenna techniques particularly for orthogonal frequency division multiplexed (OFDM) communications systems.
A signal processing system (800) for determining weights for an adaptive antenna, the antenna having a plurality of antenna elements (802a-d) each for receiving a signal comprising a plurality of subcarriers, the system comprising, a plurality of inputs for receiving signals from said plurality of antenna elements, a time-to-frequency domain transformer (806) for each input for transforming the signal from each input to a plurality of subcarrier signals, a first weight determiner (802) coupled to said inputs, before the time-to-frequency domain transformer in the signal path, and configured to determine a first set of weights, one for each input, and a second weight determiner (838) coupled to said first weight determiner and configured to determine, from the determination of said first set of weights, at least one second set of weights comprising a frequency-domain weight for a subcarrier signal derived from each of said inputs.
By calculating a first set of weights in the time-domain and then modifying these for each subcarrier for application in the frequency domain the weight calculation process is simplified and can be performed faster.
96 Citations
46 Claims
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1. A signal processing system for determining weights for an adaptive antenna, the antenna having a plurality of antenna elements each for receiving a signal comprising a plurality of subcarriers, the system comprising:
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a plurality of inputs for receiving signals from said plurality of antenna elements;
a time-to-frequency domain transformer for each input for transforming the signal from each input to a plurality of subcarrier signals;
a first weight determiner coupled to said inputs, before the time-to-frequency domain transformer in the signal path, and configured to determine a first set of weights, one for each input; and
a second weight determiner coupled to said first weight determiner and configured to determine, from the determination of said first set of weights, at least one second set of weights comprising a frequency-domain weight for a subcarrier signal derived from each of said inputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 45, 46)
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21. A method of determining weights for an adaptive antenna, the antenna having a plurality of antenna elements each for receiving a signal comprising a plurality of subcarriers, the method comprising:
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receiving a plurality of signals from said plurality of antenna elements;
transforming each of said plurality of received signals into a plurality of subcarrier signals;
determining a first set of weights, one for each received signal; and
determining, using the determination of said first set of weights, at least one second set of weights comprising a frequency-domain weight for a subcarrier signal derived from each of said received signal inputs signals. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method of adaptive beamforming for an OFDM antenna comprising a plurality of antenna elements, the method comprising:
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applying a first beamforming algorithm in the time domain to determine at least one antenna beam direction; and
calculating a set of weights for application in the frequency domain to versions of at least one subcarrier, each version of the subcarrier being received by a corresponding one of the antenna elements;
said set of weights being calculated using said at least one antenna beam direction.
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41. A method of calculating weights for an array antenna for receiving an orthogonal frequency division multiplexed (OFDM) signal comprising a plurality of subcarriers, the method comprising:
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determining, in a time domain, a direction of arrival of the OFDM signal at the array antenna; and
calculating at least one set of weights for application to the subcarriers of the OFDM signal in a frequency domain using said direction of arrival. - View Dependent Claims (42)
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43. A processing system for an adaptive antenna, the processing system configured to calculate weights for an array antenna for receiving an orthogonal frequency division multiplexed (OFDM) signal comprising a plurality of subcarriers, the system adapted for:
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determining, in a time domain, a direction of arrival of the OFDM signal at the array antenna; and
calculating at least one set of weights for application to the subcarriers of the OFDM signal in a frequency domain using said direction of arrival.
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44. A processing system for an adaptive antenna, the processing system configured to calculate weights for an array antenna for receiving an orthogonal frequency division multiplexed (OFDM) signal comprising a plurality of subcarriers, the system adapted for:
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determining, in a time domain, a direction of arrival of the OFDM signal at the array antenna; and
calculating a plurality of said sets of weights, one for each subcarrier of the OFDM signal in the frequency domain, using said direction of arrival.
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Specification