Multi-chip TX Beamforming Without Phase Alignment
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Solution Overview
Problem
Existing wireless communication devices face performance degradation due to local oscillator (LO) signal leakage when frequency synthesizers are coupled to both transmit and receive chains, which is exacerbated by the need for phase alignment circuitry that is inadequate for high-speed switching applications like per-packet beamforming.
Innovation Solution
A wireless communications device that generates phase-synchronized LO signals without phase adjustment circuitry by continuously maintaining multiple LO signals tuned to carrier frequencies, using frequency dividers to reduce timing signals to carrier frequencies and keeping them active across mode changes, ensuring constant phase relationships for rapid beamforming operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequency synthesizers are coupled to both TX and RX chains, then LO signals can be generated for both transmit and receive operations, but LO signal leakage occurs which degrades wireless radio performance
Solution Approach 1:
The patent divides the LO signal generation into separate frequency synthesizers for TX and RX chains, with each synthesizer dedicated to its respective chain. This segmentation prevents LO signal leakage from one chain affecting the other, as each synthesizer operates independently with its own phase alignment circuitry.
2Adaptability or versatility
If phase alignment circuitry is added to synchronize LO signals from multiple frequency synthesizers, then beamforming operations can be performed, but the phase alignment circuitry is inadequate for high-speed per-packet switching
Solution Approach 1:
The patent pre-synchronizes the LO signals from multiple frequency synthesizers before beamforming operations begin. By establishing phase alignment in advance using dedicated phase alignment circuitry, the system eliminates the need for real-time phase adjustment during per-packet switching, thereby enabling high-speed operation.
Solution Approach 2:
The patent introduces dedicated phase alignment circuitry as an intermediary component between the frequency synthesizers and the beamforming operation. This intermediary circuitry handles the complex phase synchronization task separately, allowing the main beamforming path to operate at full speed without phase adjustment delays.
3Speed
If multiple LO signals are maintained continuously active, then phase relationships remain constant enabling rapid beamforming switching, but power consumption increases
Solution Approach 1:
The patent maintains multiple LO signals in a pre-synchronized state before they are needed for beamforming operations. By preparing the phase relationships in advance, the system can switch between different LO signals rapidly without requiring time-consuming phase realignment, thus enabling per-packet beamforming switching.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables near-instant beamforming capabilities on a per-packet switching basis while minimizing LO leakage, allowing for efficient operation across different communication modes without the need for phase alignment circuitry, thereby enhancing wireless communication performance.
Implementation Method 1
The first frequency divider converts the first timing signal to a first LO signal by reducing a frequency of the first timing signal to a first carrier frequency. The second frequency divider converts the first timing signal to a second LO signal by reducing the frequency of the first timing signal to the first carrier frequency.
Data Source
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AI summary
A wireless communications device that produces phase-synchronized local oscillator (LO) signals without dedicated LO phase alignment circuitry. The wireless communications device includes a first transceiver chain to receive a first timing signal and a second transceiver chain to receive the first timing signal and a second timing signal. The first transceiver chain includes a first frequency divider to convert the first timing signal to a first LO signal. The second transceiver chain includes a second frequency divider to convert the first timing signal to a second LO signal, a third frequency divider to convert the second timing signal to a third LO signal, and a multiplexer to select either the second LO signal or the third LO signal for transmitting wireless signals via the second transceiver chain based at least in part on an operating mode of the wireless communications device.