Parallel Scheduler Architecture for MU-MIMO Subcells
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Solution Overview
Problem
Current MU-MIMO systems face high scheduling requirements, limiting their ability to fully utilize capacity due to the need for efficient time- and frequency-scheduling across multiple subcells in cellular communication systems.
Innovation Solution
A method and apparatus for performing time- and frequency-scheduling in access nodes with multiple subcells, involving selecting active beams based on radio channel measurements, load balancing, and ensuring spatial orthogonality for high-priority terminal devices, allowing for common time-scheduling and parallel frequency-scheduling across subcells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MU-MIMO technology is used to increase radio link capacity through multiple transmit and receive antennas, then the capacity is improved, but the scheduling requirements become very high
Solution Approach 1:
The cell is divided into multiple subcells, and the scheduling function is segmented into common time-scheduling and separate frequency-scheduling for each subcell. This segmentation allows parallel processing of scheduling decisions, reducing the overall scheduling complexity while maintaining high capacity through MU-MIMO.
Solution Approach 2:
The patent introduces spatial dimension through beamforming and subcell division. By scheduling users in different spatial directions (different subcells with different active beams), the system can perform parallel frequency-scheduling across multiple spatial dimensions, effectively reducing the computational burden of scheduling while increasing capacity.
2Reliability
If common time-scheduling is performed for the whole cell, then scheduling coordination is improved, but frequency-scheduling efficiency is reduced due to sequential processing
Solution Approach 1:
The scheduling process is segmented into two independent stages: common time-scheduling for the entire cell, and separate frequency-scheduling for each subcell. This segmentation enables parallel execution of frequency-scheduling operations across multiple subcells, improving efficiency while maintaining coordination through the initial time-scheduling phase.
Solution Approach 2:
Common time-scheduling is performed as a preliminary action before separate frequency-scheduling. This preliminary coordination establishes the time-domain framework for the entire cell, after which frequency-scheduling can proceed in parallel for each subcell without compromising overall coordination.
3Quantity of substance
If multiple users are co-scheduled on the same time-frequency resource using MU-MIMO, then capacity is increased, but scheduling complexity and computational requirements increase
Solution Approach 1:
The cell is segmented into multiple subcells with distinct active beams. Users are co-scheduled within each subcell's spatial domain, which reduces the overall scheduling complexity by dividing the large-scale scheduling problem into smaller, manageable subproblems that can be processed in parallel.
Solution Approach 2:
The patent utilizes the spatial dimension created by beamforming to enable parallel scheduling. By assigning users to different spatial subcells with orthogonal beams, the system can perform frequency-scheduling in parallel across spatial dimensions, reducing computational complexity while maintaining high user capacity through MU-MIMO.
Data Source
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AI summary
According to an aspect, there is provided a method for performing in an access node time- and frequency scheduling for a cell comprising two or more subcells. The method comprises the following steps. The access node selects a set of one or more active beams for each of at least two of subcells comprised in the two or more subcells from beams produced by an antenna array of the access node. The access node performs time-scheduling for the cell in common. Finally, the access node performs frequency-scheduling separately and in parallel for each of the at least two subcells for transmission using a corresponding set of one or more active beams.