System and method for antenna diversity using equal power joint maximal ratio combining
First Claim
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1. A wireless communication device, comprising:
- a plurality of N antennas;
a baseband processor configured to determine a receive weight vector of a plurality of complex receive antenna weights for each of the plurality of N antennas, the receive antenna weights applied to a received baseband signal;
compute a transmit weight vector by computing a conjugate of the receive weight vector, the transmit weight vector comprising a complex transmit antenna weight for each of plurality of N antennas of the communication device, wherein each complex transmit antenna weight has a magnitude and a phase whose values may vary with frequency across a bandwidth of the baseband signal, thereby generating a plurality of N transmit signals each of which is weighted across the bandwidth of the baseband signal to be transmitted from corresponding ones of the plurality of N antennas to a second communication device, wherein the magnitude of the complex transmit antenna weight associated with each antenna is such that the power to be output at each antenna is the same and is equal to the total power to be output by all of the N antennas divided by N and such that the sum of the power at each corresponding frequency across the plurality of transmit signals is equal to a constant;
apply the transmit weight vector to a baseband signal for transmission via the plurality of N antennas; and
update the transmit weight vector by repeating the determining of the receive weight vector and computing of the transmit weight vector each time signals are received to update the transmit weight vector.
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Abstract
An equal gain composite beamforming technique which includes the constraint that the power of the signal output by each antenna is the same, and is equal to the total power of the transmit signal divided by the number N of transmit antennas from which the signal is to be transmitted. By reducing output power requirements for each power amplifier, the silicon area of the power amplifiers are reduced by as much as N times (where N is equal to the number of transmit antennas) relative to a non-equal gain composite beamforming technique.
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Citations
5 Claims
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1. A wireless communication device, comprising:
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a plurality of N antennas; a baseband processor configured to determine a receive weight vector of a plurality of complex receive antenna weights for each of the plurality of N antennas, the receive antenna weights applied to a received baseband signal; compute a transmit weight vector by computing a conjugate of the receive weight vector, the transmit weight vector comprising a complex transmit antenna weight for each of plurality of N antennas of the communication device, wherein each complex transmit antenna weight has a magnitude and a phase whose values may vary with frequency across a bandwidth of the baseband signal, thereby generating a plurality of N transmit signals each of which is weighted across the bandwidth of the baseband signal to be transmitted from corresponding ones of the plurality of N antennas to a second communication device, wherein the magnitude of the complex transmit antenna weight associated with each antenna is such that the power to be output at each antenna is the same and is equal to the total power to be output by all of the N antennas divided by N and such that the sum of the power at each corresponding frequency across the plurality of transmit signals is equal to a constant; apply the transmit weight vector to a baseband signal for transmission via the plurality of N antennas; and update the transmit weight vector by repeating the determining of the receive weight vector and computing of the transmit weight vector each time signals are received to update the transmit weight vector. - View Dependent Claims (2, 3, 4, 5)
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Specification