Beam Search Complexity Reduction via Global and Local Modes
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Solution Overview
Problem
Current millimeter-wave communication systems face challenges in efficiently determining optimal beamforming directions due to high complexity in beam and precoder search processes, especially in 3D beamforming and multi-carrier systems, leading to increased hardware complexity and power consumption.
Innovation Solution
The implementation of different beam search modes, such as global and local search modes, combined with spectral staggering of beam search modes, reduces peak complexity by temporal and spectral distribution of CSI estimation, allowing for more efficient beam index and precoder searches in multi-carrier systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beam and precoder search processes are performed using brute-force methods in 3D beamforming and multi-carrier systems, then comprehensive beam coverage and signal quality are achieved, but computational complexity and power consumption increase significantly
Solution Approach 1:
The patent segments the beam search process into two distinct modes: global search mode that performs comprehensive beam evaluation across all carriers, and local search mode that performs limited beam evaluation on a subset of carriers. This segmentation allows the system to balance between comprehensive assessment and computational complexity by selectively applying different search depths to different carriers based on channel conditions and QoS requirements.
Solution Approach 2:
The patent applies partial action by implementing localized search mode where only a subset of carriers undergoes full beam evaluation while others use simplified procedures. This partial approach reduces overall computational complexity while maintaining adequate beam quality for most carriers, trading off some assessment precision for reduced device complexity and power consumption.
2Productivity
If exhaustive beam search is performed across all component carriers, then optimal beamforming directions are identified, but peak computational load and power consumption increase
Solution Approach 1:
The patent implements periodic switching between global search mode and local search mode across different transmission time intervals and carriers. This periodic action allows the system to alternate between comprehensive beam searches (global mode) and simplified searches (local mode), thereby reducing average power consumption while periodically ensuring optimal beamforming accuracy when needed.
Solution Approach 2:
The patent introduces dynamic beam search strategies where the search mode (global or local) and search parameters are adaptively adjusted based on channel conditions, QoS requirements, and current computational load. This dynamic approach allows the system to optimize the balance between beam search accuracy and power consumption in real-time, rather than using a fixed exhaustive search approach.
3Productivity
If multi-carrier beamforming is implemented with full CSI estimation, then spectral efficiency is improved, but hardware complexity and processing requirements increase
Solution Approach 1:
The patent segments the CSI estimation process across different carriers and time intervals, performing full CSI estimation only for selected carriers in global search mode while using simplified or cached CSI for other carriers in local search mode. This segmentation reduces hardware complexity and processing requirements while maintaining multi-carrier beamforming capabilities and spectral efficiency.
Solution Approach 2:
The patent performs preliminary beam search and CSI estimation in global search mode, storing results for reuse in subsequent local search modes. This preliminary action reduces the need for repeated full CSI estimation across all carriers, thereby reducing hardware complexity and processing requirements while maintaining spectral efficiency through informed beamforming decisions.
Data Source
AI summary
An apparatus of a user equipment (UE) may include memory and processing circuitry coupled to the memory. The processing circuitry may be configured to estimate a communication channel for a multi-carrier signal based on a received reference signal, the multi-carrier signal aggregating a plurality of component carriers. During a transmission time interval of the multi-carrier signal, the UE can perform a global search over a beam search space to obtain a beam index recommendation for a component carrier of the plurality of component carriers. The beam index recommendation corresponds to a maximized channel quality metric of the estimated communication channel and is indicative of a beam grid within the beam search space. The UE can perform a localized search of a subset of the beam search space to obtain a second beam index recommendation for a second component carrier of the plurality of component carriers.