Adaptive User-Specific Beamforming via Spatial Channel Segmentation
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Solution Overview
Problem
Current wireless communications networks face challenges in achieving efficient user-specific beam forming, particularly in three-dimensional propagation environments where multipath fading occurs in both azimuth and elevation domains, leading to suboptimal beamforming gains and increased signaling overhead.
Innovation Solution
A method and network node that acquire uplink user-specific spatial channel characteristics to adaptively configure user-specific ports, determining a downlink user-specific port mapping to match the propagation channel of wireless devices, thereby enabling efficient user-specific beam forming without the need for exhaustive sampling of the whole spatial channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If user-specific 2D beamforming is implemented to match propagation channel in both elevation and azimuth domains, then beamforming gain and coverage are improved, but device complexity and codebook design difficulty increase
Solution Approach 1:
The patent segments the 2D beamforming problem into separate 1D beamforming operations in elevation and azimuth domains. The codebook is divided into elevation beamforming vectors and azimuth beamforming vectors, which can be independently designed and selected. This segmentation simplifies the overall codebook design while maintaining the ability to provide user-specific beamforming in both dimensions.
Solution Approach 2:
The patent transitions from designing a complex 2D codebook to using separate 1D codebooks for elevation and azimuth. By changing the dimensional approach from a single 2D structure to two independent 1D structures, the design complexity is reduced while still achieving 2D beamforming capability through the combination of both dimensions.
2Measurement precision
If exhaustive sampling of the whole spatial channel is performed to determine optimal beamforming weights, then beamforming accuracy is improved, but signaling overhead and energy consumption increase
Solution Approach 1:
Instead of performing exhaustive sampling of the entire 2D spatial channel, the patent uses partial sampling by separately measuring and evaluating elevation and azimuth channel characteristics. The wireless device determines channel characteristics in each dimension independently, which reduces the total number of measurements and feedback requirements while still achieving accurate user-specific beamforming.
Solution Approach 2:
The channel measurement and feedback process is segmented into separate elevation and azimuth components. The wireless device measures channel characteristics independently in each dimension and provides feedback for each separately, reducing the overall signaling overhead compared to transmitting complete 2D channel state information.
3Adaptability or versatility
If 2D planar active antenna array is used to control radiation patterns in both elevation and azimuth, then spatial degrees of freedom are improved, but antenna system complexity increases
Solution Approach 1:
The 2D planar antenna array is segmented into separate elevation and azimuth subarrays, with independent beamforming control for each dimension. This segmentation allows the system to maintain full 2D spatial control capability while simplifying the control architecture by treating each dimension independently, reducing the complexity of weight calculation and application.
Solution Approach 2:
The patent implements dynamic beamforming where the network node can adaptively select and apply different beamforming weights in elevation and azimuth based on real-time channel conditions. This dynamic adaptation allows the system to optimize performance for different user locations and channel characteristics while maintaining a manageable system through modular weight selection from pre-defined codebooks.
Data Source
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AI summary
There is provided mechanisms for adaptive user-specific beam forming. A method is performed by a network node. The method comprises acquiring uplink user-specific spatial channel characteristics for a wireless device. The method comprises acquiring a set of downlink port mappings for the wireless device. The method comprises adaptively configuring user-specific ports for the wireless device by using the uplink user-specific spatial channel statistics to determine a downlink user-specific port mapping from the set of downlink port mappings, thereby providing user-specific beam forming for the wireless device.