Analog Precoding Matrix Iterative Optimization
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Solution Overview
Problem
Current radio resource management techniques in wideband millimeter wave (mmWave) systems face challenges in efficiently optimizing user scheduling and RF beamforming due to high computational complexity and huge signaling overhead, especially in multi-user massive MIMO systems, leading to performance degradations.
Innovation Solution
A multistage method is proposed for joint alternate optimization of scheduling and RF beamforming, where the analog precoding matrix and multi-user groups are determined iteratively to maximize the beamforming function and scheduling function, utilizing analog precoding codewords and combining matrices to reduce complexity and improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hybrid analog/digital beamforming architectures are used to reduce the number of RF chains, then device complexity and power consumption are reduced, but manufacturing precision and processing accuracy deteriorate due to finite phase resolution of analog phase shifters
Solution Approach 1:
The patent merges analog and digital beamforming into a hybrid architecture where analog precoding handles coarse beam direction and digital processing refines the beamforming accuracy. The analog precoding matrix W and digital processing work together to achieve both low complexity and high precision, with the analog part reducing RF chain requirements and the digital part compensating for quantization effects.
Solution Approach 2:
The patent applies different processing qualities to different parts of the beamforming chain: analog processing with finite precision for the bulk of beam direction control, and digital processing with high precision for fine-tuning and compensation. This local differentiation of processing quality allows the system to achieve overall high precision while maintaining low hardware complexity.
2Productivity
If user grouping and resource allocation are performed for multi-user transmission to improve spectral efficiency, then productivity increases, but computational complexity and signaling overhead increase significantly
Solution Approach 1:
The patent segments the user set into multiple groups, where each group is served by a dedicated analog precoding matrix. This segmentation allows independent optimization of each user group, reducing the overall computational complexity of resource allocation and scheduling while maintaining high spectral efficiency through parallel processing of multiple groups.
Solution Approach 2:
The patent performs preliminary analog precoding matrix selection and user grouping before digital processing and resource allocation. By pre-determining the analog precoding matrices and user groups in advance, the system reduces the complexity of subsequent digital processing and resource management tasks.
3Reliability
If the number of antenna elements is increased to achieve high directional gain and enhance spatial multiplexing, then beamforming performance improves, but device complexity and cost increase
Solution Approach 1:
The patent combines a large number of antenna elements into a unified array served by a reduced number of RF chains through hybrid beamforming. The analog precoding network merges the signals from multiple antennas into fewer RF chains, achieving high directional gain through coherent combining while reducing the number of expensive and power-consuming RF components.
Data Source
AI summary
The invention comprising: jointly determining an analog precoding matrix FRF and a plurality of multi-user groups Gl, each multi-user group Gl being associated to a respective subcarrier l, each multi-user group Gl containing a plurality of receivers to be jointly served for a data transmission on the respective subcarrier l; and using the analog precoding matrix FRF for processing at least one signal to transmit; characterized in that the joint determination comprises: /a/ optimizing a beamforming function ƒ(FRF, G1 . . . , GL) with respect to the analog precoding matrix FRF, the multi-user groups Gl being fixed; /b/ optimizing a scheduling function g(Gl,FRF) with respect to the multi-user groups Gl, a value of the analog precoding matrix FRF being fixed; wherein /a/ and /b/ are iteratively repeated.