Sub-array Antenna SDMA Transmitter for Millimeter Wave Systems
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Solution Overview
Problem
Current millimeter wave communication systems face challenges with high complexity, power consumption, and cost, making them unsuitable for commercial mobile communication, particularly in achieving efficient and reliable SDMA for multiple users.
Innovation Solution
A transmitter with a baseband precoder and an array of sub-array antennas, each coupled to a radio frequency (RF) chain, applies phase shifts and beamforming weights to enable spatial division multiple access (SDMA) by transmitting phase-shifted and weighted signals, simplifying the architecture and reducing complexity while maintaining beamforming gains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional millimeter wave communication systems use full digital beamforming with multiple RF chains for each antenna element, then beamforming gain and SDMA performance are improved, but system complexity and power consumption increase significantly
Solution Approach 1:
The patent divides the antenna array into multiple sub-arrays, where each sub-array is connected to a separate RF chain. This segmentation allows the system to achieve SDMA functionality with fewer RF chains than total antenna elements, reducing system complexity while maintaining beamforming capabilities. Each sub-array can be independently controlled to serve different spatial directions or users.
Solution Approach 2:
The patent transitions from a fully digital beamforming approach (one RF chain per antenna element) to a hybrid approach by introducing spatial dimensionality through sub-array segmentation. This allows the system to exploit spatial degrees of freedom across sub-arrays to achieve multi-user SDMA functionality without proportionally increasing the number of RF chains, thereby reducing overall system complexity.
2Reliability
If traditional millimeter wave communication systems use full digital beamforming with multiple RF chains for each antenna element, then beamforming gain and SDMA performance are improved, but power consumption increases significantly
Solution Approach 1:
By segmenting the antenna array into sub-arrays with fewer RF chains, the patent reduces the number of power-consuming RF components. Each RF chain serves multiple antenna elements through the sub-array structure, thereby reducing overall power consumption while maintaining the capability to serve multiple users through spatial division.
Solution Approach 2:
Each RF chain is designed to serve multiple functions by controlling different sub-arrays for different users or spatial directions. This multi-functionality allows the system to achieve SDMA performance with fewer RF chains, thereby reducing power consumption while maintaining reliable multi-user support.
3Device complexity
If fewer RF chains are used with sub-array configuration, then system complexity and power consumption are reduced, but beamforming gain and SDMA capability may be compromised
Solution Approach 1:
The patent compensates for the reduced number of RF chains by exploiting the spatial dimensionality provided by multiple sub-arrays. Each sub-array contributes to the overall beamforming gain through coherent combining, and the spatial separation of sub-arrays provides additional degrees of freedom for multi-user SDMA, thereby maintaining beamforming performance with reduced complexity.
Solution Approach 2:
The patent combines the beamforming capabilities of multiple sub-arrays to achieve overall beamforming gain. By coherently combining the signals from different sub-arrays controlled by separate RF chains, the system achieves beamforming performance comparable to or exceeding traditional approaches, while using fewer RF chains and reducing system complexity.
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 reduces system complexity and power consumption while enabling efficient SDMA for multiple users, overcoming the limitations of existing millimeter wave communication systems by leveraging the benefits of beamforming and antenna array configurations.
Implementation Method 1
an array of sub-array antennas and a plurality of radio frequency (RF) chains configured to apply a phase shift and beamforming weight to the signal
Implementation Method 2
applying, by each of a plurality of radio frequency (RF) chains, a phase shift and beamforming weight to the signal
Data Source
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AI summary
A system is configured to perform Spatial Division Multiple Access. The system includes at least one transmitter or receiver capable of polarization alignment. The transmitter includes a baseband precoder configured to precode a signal, an array of sub-array antennas and a plurality of radio frequency (RF) chains. Each RF chain is coupled to a respective antenna sub-array of the array of antennas. The transmitter is configured to perform a method that includes precoding, by a baseband precoder, a signal for spatial division multiple access (SDMA). The method also includes applying, by each of the plurality of radio frequency (RF) chains, a phase shift and beamforming weight to the signal and transmitting the phase shifted and weighted signal by an array of sub-array antennas.