Integrated beamformer/modem architecture
DC CAFCFirst Claim
1. An apparatus for modulating and demodulating signals transmitted and received via an electronically steerable phased array antenna comprising a plurality of antenna elements, the apparatus comprising:
- a baseband modulator configured to modulate outbound digital baseband signals to be transmitted via the phased array antenna;
a baseband demodulator configured to demodulate incoming digital baseband signals generated from signals received via the phased array antenna; and
a shared baseband processor configured to receive digital baseband signals including the modulated outbound digital baseband signals and the incoming digital baseband signals, said shared baseband processor applying a single phase adjustment to each of the digital baseband signals to jointly account for both beamforming phase rotation and carrier phase rotation of individual antenna elements.
4 Assignments
Litigations
1 Petition
Accused Products
Abstract
A transceiver employing a steerable phased-array antenna includes a modem architecture in which signals from each antenna element in the array are independently processed down to the individual baseband channel level, and digital beamforming is performed at baseband. The data rate reduction from IF to baseband permits parallel signal data from multiple antenna elements to be time multiplexed and serially processed at acceptable data rates at baseband with minimal modem hardware requirements. Both for transmit signal modulation and received signal demodulation, the computation of carrier tracking, automatic gain control (AGC)/power-control, and beamforming are shared by the same processing circuitry for all channels when performed at baseband. The resulting baseband circuitry is only incrementally larger than that required for carrier tracking and AGC alone, yet accomplishes independent beamforming for each antenna element on each user channel.
178 Citations
33 Claims
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1. An apparatus for modulating and demodulating signals transmitted and received via an electronically steerable phased array antenna comprising a plurality of antenna elements, the apparatus comprising:
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a baseband modulator configured to modulate outbound digital baseband signals to be transmitted via the phased array antenna; a baseband demodulator configured to demodulate incoming digital baseband signals generated from signals received via the phased array antenna; and a shared baseband processor configured to receive digital baseband signals including the modulated outbound digital baseband signals and the incoming digital baseband signals, said shared baseband processor applying a single phase adjustment to each of the digital baseband signals to jointly account for both beamforming phase rotation and carrier phase rotation of individual antenna elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of processing an RF signal received via an electronically steerable phased array antenna comprising a plurality of antenna elements, the method comprising:
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(a) separately down-converting the RF signal from each antenna element to an intermediate frequency (IF) signal; (b) separately analog-to-digital converting the IF signal from each antenna element; (c) separately digitally down-converting the digital IF signal from each antenna element to a digital baseband signal to form a set of parallel baseband signals from the plurality of antenna elements; (d) time multiplexing the set of parallel baseband signals to form a serial stream of digital baseband signals; (e) applying a single phase adjustment to each of the digital baseband signals in the serial stream to jointly account for both carrier phase tracking and antenna element beamforming; and (f) performing beamforming by combining digital baseband signals respectively associated with the plurality of antenna elements. - View Dependent Claims (27, 28)
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29. A method of processing signals to be transmitted via an electronically steerable phased array antenna comprising a plurality of antenna elements, the method comprising:
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(a) generating a stream of digital baseband signals representing data symbols to be transmitted via the phased array antenna, wherein digital baseband signals in the stream are associated with individual antenna elements; (b) applying a single phase adjustment to each of the digital baseband signals to jointly account for both carrier phase rotation and antenna element beamforming; (c) demultiplexing the stream of digital baseband signals into a plurality of parallel signals respectively associated with individual antenna elements; (d) digitally up-converting the parallel signals to produce a plurality of digital intermediate frequency (IF) signals respectively associated with individual antenna elements; (e) digital-to-analog converting the digital IF signals to produce a plurality of analog IF signals respectively associated with individual antenna elements; and (f) up-converting the analog IF signals to RF signals for transmission via the phased array antenna. - View Dependent Claims (30)
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31. An apparatus for modulating and demodulating signals transmitted and received via an electronically steerable phased array antenna comprising a plurality of antenna elements, the apparatus comprising:
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a baseband modulator configured to modulate outbound digital baseband signals to be transmitted via the phased array antenna; a baseband demodulator configured to demodulate incoming digital baseband signals generated from signals received via the phased array antenna; and a shared baseband processor configured to receive digital baseband signals including the modulated outbound digital baseband signals and the incoming digital baseband signals, said shared baseband processor applying phases to the digital baseband signals to account for both beamforming phase rotation and carrier phase rotation of individual antenna elements, wherein the shared baseband processor generates a stream of combined phase adjustments by summing a stream of carrier phases for the digital baseband signals with a stream of beam rotation phases for the digital baseband signals, and adjusts phases of the digital baseband signals in accordance with the combined phase adjustments.
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32. A method of processing an RF signal received via an electronically steerable phased array antenna comprising a plurality of antenna elements, the method comprising:
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(a) separately down-convening the RF signal from each antenna element to an intermediate frequency (IF) signal; (b) separately analog-to-digital convening the IF signal from each antenna element; (c) separately digitally down-convening the digital IF signal from each antenna element to a digital baseband signal to form a set of parallel baseband signals from the plurality of antenna elements; (d) time multiplexing the set of parallel baseband signals to form a serial stream of digital baseband signals; (e) generating a stream of carrier phases for the digital baseband signals; (f) generating a stream of beam rotation phases for the digital baseband signals; (g) summing the beam rotation phases and the carrier phases to produce a stream of combined phase adjustments; (h) applying the stream of combined phase adjustments to the digital signals in the serial stream to account for both carrier phase tracking and antenna element beamforming; and (i) performing beamforming by combining digital baseband signals respectively associated with the plurality of antenna elements.
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33. A method of processing signals to be transmitted via an electronically steerable phased array antenna comprising a plurality of antenna elements, the method comprising:
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(a) generating a stream of digital baseband signals representing data symbols to be transmitted via the phased array antenna, wherein digital baseband signals in the stream are associated with individual antenna elements; (b) generating a stream of carrier phases for the digital baseband signals; (c) generating a stream of beam rotation phases for the digital baseband signals; (d) summing the beam rotation phases and the carrier phases to produce a stream of combined phase adjustments; (e) applying the stream of combined phase adjustments to the stream of digital baseband signals to account for both carrier phase rotation and antenna element beamforming; (f) demultiplexing the stream of digital baseband signals into a plurality of parallel signals respectively associated with individual antenna elements; (g) digitally up-converting the parallel signals to produce a plurality of digital intermediate frequency (IF) signals respectively associated with individual antenna elements; (h) digital-to-analog converting the digital IF signals to produce a plurality of analog IF signals respectively associated with individual antenna elements; and (i) up-converting the analog IF signals to RF signals for transmission via the phased array antenna.
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Specification