MU-MIMO Co-Scheduling with Subarray-Aware Interference Estimation
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Solution Overview
Problem
Current MU-MIMO systems employing antenna subarrays face suboptimal link adaptation and user pairing due to reliance on orthogonality of reported precoders, which does not account for subarray radiation patterns and grating lobes, leading to increased interference and reduced system performance.
Innovation Solution
A method for improving MU-MIMO co-scheduling decisions by calculating interference estimates using candidate precoder matrices and parameters specific to antenna subarrays, including signal mapping and subarray geometry, to determine optimal co-scheduling combinations that minimize interference, thereby enhancing link adaptation and user pairing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional MU-MIMO systems rely on orthogonality of reported precoders for user pairing, then the system operation is simplified, but interference estimation accuracy deteriorates due to not accounting for subarray radiation patterns and grating lobes
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing subarray radiation patterns and grating lobe characteristics before user pairing decisions are made. The network entity maintains a database of antenna array parameters including subarray geometry and radiation characteristics, which are prepared in advance to enable accurate interference estimation during the actual MU-MIMO scheduling process without complicating the real-time operation
Solution Approach 2:
The patent introduces an intermediary calculation layer that bridges the simple orthogonality check and the actual interference estimation. The network entity computes an adjusted interference metric that incorporates subarray radiation patterns as an intermediate step between receiving precoder reports and making final user pairing decisions. This intermediary computation accounts for grating lobes and subarray characteristics without requiring complete redesign of the user pairing mechanism
2Device complexity
If antenna arrays are divided into subarrays to reduce hardware complexity, then device complexity is reduced, but link adaptation performance deteriorates due to increased interference from grating lobes
Solution Approach 1:
The patent applies parameter changes by modifying the interference estimation parameters to include subarray-specific characteristics. The network entity adjusts the interference calculation to incorporate subarray radiation patterns, grating lobe positions, and signal mapping configurations. These parameter adjustments enable accurate performance prediction for MU-MIMO transmissions without requiring changes to the physical antenna subarray structure
Solution Approach 2:
The patent implements feedback by using the calculated interference estimates to improve subsequent user pairing and link adaptation decisions. The network entity uses the accurate interference predictions from subarray-aware calculations to make better co-scheduling decisions, creating a feedback loop where measurement accuracy improves system performance, which in turn generates better measurements
Data Source
AI summary
A network entity and method for co-scheduling receivers in a multi-user, multiple-input multiple-output communication system of the kind that uses antenna subarrays are described. In a method implementation candidate precoder matrix indicators are received. Interference estimates are computed relating to the interference caused by the transmission signal to one receiver on the transmission signal(s) to the other receiver(s). On that basis, a co-scheduling combination is chosen which is predicted to provide an adequately low interference based on these interference estimates. The interference estimate calculation includes at least one parameter specific to the antenna subarrays of the transmitting antenna array.