Multistage beamforming of multiple-antenna communication system
First Claim
1. A multistage beamforming circuit in a wireless communication network, the circuit comprising:
- a data unit configured to;
implement a frequency domain beamforming stage by converting K received data streams into M precoding output streams in a frequency-domain, andtransform the M output streams to M orthogonal frequency-division multiplexing (OFDM) time domain signals;
the data unit comprising;
a frequency domain precoding module configured to receive and precode the K received data streams into the M precoding output streams by applying frequency domain precoding matrices;
M Inverse Fast Fourier Transform (IFFT) processing blocks for processing the M precoding output streams to yield the M OFDM time-domain signals, each IFFT processing block configured to;
receive a frequency-domain signal,map the frequency-domain signal to resource elements in a frequency domain,transform the frequency-domain signal to a stream of time domain samples, andadd a cyclical prefix to the stream of time domain samples yielding an OFDM time-domain signal; and
a remote radio head configured to implement a time-domain broadband beamforming stage by converting the M OFDM time-domain signals into N transmit streams of time-domain samples based on beamforming control signals received from the data unit, the beamforming control signals indicating a wideband precoding matrix or a set of indicators to construct the wideband precoding matrix, the remote radio head comprising a transmit antenna array configured to transmit the N transmit streams that together form broadcast beams and user-specific beams, the antenna array including a plurality of physical antennas,wherein the number N of transmit streams is greater than the number M of precoding output streams, andwherein N. M. and K are positive integers.
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Accused Products
Abstract
A multistage beamforming circuit includes a data unit that implements a frequency domain beamforming stage and a remote radio head that implements a time-domain broadband beamforming stage. The data unit implements the frequency domain beamforming stage by converting K received data streams into M precoding output streams in a frequency-domain. The data unit is configured to transform the M output streams to M OFDM time-domain signals. The remote radio head, or integrated radio unit is configured to implement a time-domain broadband beamforming stage by converting the M OFDM time-domain signals into N transmit streams of time-domain samples. The remote radio head, or integrated radio unit includes a transmit antenna array configured to transmit the N transmit streams that together form broadcast beams and user-specific beams. The antenna array includes a plurality of physical antennas. The number N of transmit streams is greater than the number M of precoding output streams.
24 Citations
22 Claims
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1. A multistage beamforming circuit in a wireless communication network, the circuit comprising:
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a data unit configured to; implement a frequency domain beamforming stage by converting K received data streams into M precoding output streams in a frequency-domain, and transform the M output streams to M orthogonal frequency-division multiplexing (OFDM) time domain signals; the data unit comprising; a frequency domain precoding module configured to receive and precode the K received data streams into the M precoding output streams by applying frequency domain precoding matrices; M Inverse Fast Fourier Transform (IFFT) processing blocks for processing the M precoding output streams to yield the M OFDM time-domain signals, each IFFT processing block configured to; receive a frequency-domain signal, map the frequency-domain signal to resource elements in a frequency domain, transform the frequency-domain signal to a stream of time domain samples, and add a cyclical prefix to the stream of time domain samples yielding an OFDM time-domain signal; and a remote radio head configured to implement a time-domain broadband beamforming stage by converting the M OFDM time-domain signals into N transmit streams of time-domain samples based on beamforming control signals received from the data unit, the beamforming control signals indicating a wideband precoding matrix or a set of indicators to construct the wideband precoding matrix, the remote radio head comprising a transmit antenna array configured to transmit the N transmit streams that together form broadcast beams and user-specific beams, the antenna array including a plurality of physical antennas, wherein the number N of transmit streams is greater than the number M of precoding output streams, and wherein N. M. and K are positive integers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A base station for multistage beamforming in a wireless communication network, the base station comprising:
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a data unit configured to implement a frequency domain beamforming stage, the data unit comprising; a frequency domain precoding module configured to receive and precode K data streams into M precoding output streams in a frequency domain by applying frequency domain precoding matrices, M pairs of an Inverse Fast Fourier Transform (IFFT) processing block coupled to M cyclic prefix processing block, each pair configured to transform the M precoding output streams into M orthogonal frequency-division multiplexing (OFDM) time-domain signals, wherein each IFFT processing block is configured to receive a frequency-domain signal, map the frequency-domain signal to resource elements in a frequency domain, transform the received frequency-domain signal to a stream of time domain samples, and each cyclic prefix processing block is configured to add a cyclical prefix to the stream of time domain samples to generate the M precoding output streams; and a remote radio head (RRH) configured to implement a time-domain broadband beamforming stage by converting the M OFDM time-domain signals into N transmit streams of time-domain samples based on beamforming control signals received from the data unit, the beamforming control signals indicating a wide-band precoding matrix or a set of indicators to construct the wideband precoding matrix, the RRH comprising; a time-domain broadband beamforming module configured to receive and precode the M output streams into N precoded output signals using a wide-band precoding matrix, a transmit antenna array configured to transmit the N transmit streams that together form broadcast beams and user-specific beams, the antenna array including a plurality of physical antennas, wherein the number N of transmit streams is greater than the number M of precoding output streams in the time domain, and wherein N. M. and K are positive integers. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A multistage beamforming method comprising:
- implementing a frequency domain beamforming stage by converting K data streams in a frequency-domain into M precoding output streams in a frequency domain, wherein converting the K data streams into M precoding output streams comprises receiving and precoding the K data streams into M precoding output streams by applying frequency domain precoding matrices;
transforming the M output streams to M orthogonal frequency-division multiplexing (OFDM) time-domain signals by; mapping the M output streams to resource elements in a frequency domain to generate M mapped frequency-domain signals, transforming the M mapped frequency-domain signals to M streams of time domain samples using Inverse Fast Fourier Transform (IFFT), and adding a cyclical prefix to each of the M streams of time domain samples yielding the M OFDM time-domain signals; implementing a time-domain broadband beamforming stage by converting the M OFDM time-domain signals into N transmit streams of time-domain samples based on beamforming control signals received, the beamforming control signals indicating a wide-band precoding matrix or a set of indicators to construct the wideband precoding matrix; and transmitting, by a transmit antenna array including a plurality of physical antennas, the N transmit streams that together form broadcast beams and user-specific beams, wherein the number N of transmit streams is greater than the number M of precoding output streams, and wherein N. M. and K are positive integers. - View Dependent Claims (20, 21, 22)
- implementing a frequency domain beamforming stage by converting K data streams in a frequency-domain into M precoding output streams in a frequency domain, wherein converting the K data streams into M precoding output streams comprises receiving and precoding the K data streams into M precoding output streams by applying frequency domain precoding matrices;
Specification