MIMO Scheduling via Layer Capacity Imbalance

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Solution Overview

Problem

In MIMO communication systems, existing technologies face challenges in optimizing resource allocation among user equipment (UEs) due to lack of knowledge about other UEs' precoders, leading to suboptimal system throughput and inability to employ advanced receivers, especially in scenarios with high transmit correlation and layer performance imbalances.

Innovation Solution

The system logic in a MIMO communication interface identifies UEs with common preferred precoders causing layer capacity imbalances and allocates them to specific layers for transmission, allowing for simultaneous communication using these precoders, thereby optimizing resource usage and improving system throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional MIMO scheduling is used without knowledge of other UEs' precoders, then device complexity is reduced, but system throughput deteriorates and resource allocation optimization is lost

Engineering Contradiction:
Improvesystem throughputVSAvoidscheduling complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system implements feedback mechanisms where UEs report their preferred precoders and layer capacity information to the base station. The base station uses this feedback to make informed scheduling decisions, matching UEs with complementary layer imbalances while accounting for their preferred precoders, thereby optimizing system throughput without excessive complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary analysis of UE preferred precoders and layer capacity imbalances before final scheduling decisions. By pre-identifying UEs with complementary characteristics (one UE with layer 1 > layer 2 and another with layer 2 > layer 1), the system prepares optimal scheduling candidates in advance, improving throughput while managing complexity

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If UEs are allocated without considering layer capacity imbalance, then ease of operation is improved, but manufacturing precision of resource allocation deteriorates

Engineering Contradiction:
Improveresource allocation precisionVSAvoidscheduling operation simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system applies different scheduling strategies to different UEs based on their local characteristics (preferred precoders and layer capacity imbalances). Each UE is evaluated individually for its layer 1 vs layer 2 capacity ratio, and scheduling decisions are customized to match UEs with complementary local qualities, achieving precise resource allocation

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes scheduling parameters by considering both preferred precoder indices and layer capacity imbalance metrics. By introducing these additional parameters into the scheduling decision process, the system achieves more precise resource allocation while maintaining manageable operational complexity through systematic evaluation

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If advanced receivers are employed, then measurement precision improves, but device complexity increases

Engineering Contradiction:
ImproveSINR measurement precisionVSAvoidreceiver complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary precoder selection and layer assignment before data reception, so that UEs know in advance which precoder and layer configuration to expect. This preliminary action enables UEs to configure their receivers optimally for the assigned parameters, achieving high SINR measurement precision without requiring complex adaptive receivers

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2688221B1Enhanced Multi-User MIMO Scheduling
Publication Date: 2019.08.21 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP2688221B1 patent drawingFigure 1
  • EP2688221B1 patent drawingFigure 2
  • EP2688221B1 patent drawingFigure 3

AI summary

A spatial multiplexing scheduler in, for example, an eNB or other base station, determines rank n precoders for UEs. Each UE reports the preferred precoder from this set of rank n precoders. The preferred precoder results in imbalance in performance over m layers compared to the rest of (n-m) layers. The UEs also report channel quality to the eNB, from which the eNB determines which layer(s) is better for the UE. For example, when n=2 and m=1, the eNB may then select two UEs such that, for the same precoder used by the UEs, the first UE has much higher layer 1 performance than layer 2, and the second UE has much higher layer 2 performance than layer 1. These two UEs may then share the same frequency-time domain resources, with the first UE information sent / received on layer 1, while the second UE information is sent / received on layer 2.