Wireless communication system using a plurality of antenna elements with adaptive weighting and combining techniques
First Claim
1. A method for operating a wireless communication system receiver comprising the steps of:
- receiving a plurality of input signals;
weighting said plurality of input signals; and
combining said weighted plurality of signals to form an output signal, wherein weights used in said weighting step are adjusted to increase power in said output signal of in-band components and decrease power in said output signal of out-of-band components, wherein said weights are determined by maximal ratio combining (MRC) to align phases of said input signals to the same phase and to scale said input signals in proportion to a square root of a received signal-to-noise ratio.
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Abstract
The present invention provides a method and system for operating a wireless communication system in which received signals from a plurality of antennas are weighted and combined with a beam forming operation to form an output signal. The beam forming operation determines weights adjusted to increase a desired signal power in the output signal while reducing the power in the output signal of out-of-band components. In an embodiment of the present invention, beam forming operations are performed with maximal ratio combining (MRC). Alternatively, a constant modulus algorithm (CMA) can be used for beam forming operations. In an alternate embodiment, improved interference suppression is performed with a novel algorithm referred to as an interference nulling algorithm (INA). The INA receives an error signal which is 180° out of phase with a combination of the channels for individual antennas, referred to as the SUM channel. The error signal is determined by complex conjugate multiplication of the individual signals and a reference complex signal. It is desirable to simultaneously achieve diversity and combining gain and suppress the adjacent channel by combining the weight generation for MRC and that for INA, as described above, to generate antenna weights similar to those of MMSE combining.
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Citations
23 Claims
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1. A method for operating a wireless communication system receiver comprising the steps of:
- receiving a plurality of input signals;
weighting said plurality of input signals; and
combining said weighted plurality of signals to form an output signal, wherein weights used in said weighting step are adjusted to increase power in said output signal of in-band components and decrease power in said output signal of out-of-band components, wherein said weights are determined by maximal ratio combining (MRC) to align phases of said input signals to the same phase and to scale said input signals in proportion to a square root of a received signal-to-noise ratio. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10)
- receiving a plurality of input signals;
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7. The method of 1 wherein said weights used in said weighting step are adjusted by the step of adding an error signal into said weights to cancel said out-of-band components wherein said error signal is 180 degrees out of phase with a sum channel combining said plurality of input signals.
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11. A method for operating a transmit and receive beam forming system comprising the steps of:
- a. receiving a plurality of input signals;
b. weighting said plurality of input signals with weights, weights are adjusted to increase power in said output signal of in-band components and decrease power in said output signal of out-of-band components; and
c. combining said weighted plurality of signals to form an output signal;
d. transmitting a beam towards a desired signal detecting wherein a complex conjugate said weights are used for transmitting said beam wherein after said step b. said weights are frozen and said weights are applied for transmitting in step d wherein said input signal is a time division duplex signal and a control signal is used to freeze said weights at an end of packet and use said weights for transmitting a signal in step d. - View Dependent Claims (12)
- a. receiving a plurality of input signals;
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13. A system for operating a wireless communication system receiver comprising:
- means for receiving a plurality of input signals;
means for weighting said plurality of input signals; and
means for combining said weighted plurality of signals to form an output signal, wherein weights used in said weighting step are adjusted to increase power in said output signal of in-band components and decrease power in said output signal of out-of-band components wherein said weights are determined by maximal ratio combining (MRC) to align phases of said input signals to the same phase and to scale input signals in proportion to a square root of a received signal-to-noise ratio. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
- means for receiving a plurality of input signals;
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22. A system for operating a transmit and receive beam forming system comprising:
- means for receiving a plurality of input signals;
means for weighting said plurality of input signals with weights, weights are adjusted to increase power in said output signal of in-band components and decrease power in said output signal of out-of-band components; and
means for combining said weighted plurality of signals to form an output signal;
means for transmitting a beam towards a desired signal detecting wherein a complex conjugate said weights are used for transmitting said beam wherein said input signal is a time division duplex signal and a control signal is used to freeze said weights at an end of packet and use said weights is said means for transmitting a beam wherein said control signal occurs at an end of a preamble of said packet and when said control signal occurs said weights are frozen and are used in said means for transmitting. - View Dependent Claims (23)
- means for receiving a plurality of input signals;
Specification