MIMO User Equipment Grouping for Scheduling and CQI Interpretation

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Solution Overview

Problem

Wireless multiple-access systems face challenges in efficiently supporting multiple-input multiple-output (MIMO) transmission due to complexities in scheduling and interpreting channel quality information across various user equipment (UE) configurations.

Innovation Solution

Classifying UEs into groups for MIMO transmission based on criteria such as antenna numbers, loading, and data requirements, allowing for individual or simultaneous scheduling, and interpreting channel quality indicator (CQI) information differently for each group to optimize power distribution and interference cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UEs are scheduled individually for MIMO transmission, then transmission reliability is improved, but system productivity decreases due to reduced resource utilization

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidsystem capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments UEs into two distinct groups: first group UEs scheduled individually for reliable MIMO transmission, and second group UEs scheduled together for improved system capacity. This segmentation allows the system to apply different scheduling strategies to different UE types, optimizing both reliability and productivity simultaneously.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single CQI interpretation method is used for all UEs, then system complexity is reduced, but measurement precision deteriorates due to ambiguous channel quality assessment

Engineering Contradiction:
Improvesystem complexityVSAvoidCQI interpretation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by implementing different CQI interpretation methods for different UE groups. First group UEs use a first CQI interpretation method tailored to their individual scheduling characteristics, while second group UEs use a second CQI interpretation method optimized for their multi-UE scheduling context. This localized approach improves measurement precision without significantly increasing overall system complexity.

Inventive Principle:
Principle #3Local quality

3Productivity

If MIMO transmission is scheduled to multiple UEs simultaneously, then system productivity increases, but device complexity increases due to coordinated scheduling requirements

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

Solution Approach 1:

The patent segments the UE population into two groups with different scheduling approaches. Second group UEs are specifically designed to be scheduled together in groups, which increases system capacity. The segmentation allows the scheduler to manage complexity by applying group-based scheduling rules to the second group, rather than handling each UE individually.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges second group UEs into scheduling groups for simultaneous MIMO transmission. By combining multiple second group UEs into cohorts that are scheduled together, the system achieves higher productivity through improved resource utilization while managing complexity through standardized group scheduling procedures.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If UE classification is performed frequently to adapt to changing conditions, then adaptability is improved, but loss of time increases due to reclassification overhead

Engineering Contradiction:
ImproveUE reclassification flexibilityVSAvoidreclassification time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent implements a dynamic UE classification system where UEs can be reclassified between the first and second groups based on changing operating conditions. The classification criteria include UE capability, channel conditions, and system load, allowing the system to adapt to dynamic environments while managing reclassification overhead through event-triggered updates rather than continuous reevaluation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1997255B1Grouping of users for MIMO transmission in a wireless communication system
Publication Date: 2015.10.07 QUALCOMM INC
  • EP1997255B1 patent drawingFigure 1
  • EP1997255B1 patent drawingFigure 2
  • EP1997255B1 patent drawingFigure 3~4

AI summary

Techniques for supporting MIMO transmission are described. User equipments (UEs) are classified into a first group of UEs to be scheduled individually and a second group of UEs that can be scheduled together. The classification may be based upon the number of transmit and receive antennas, sector loading, data requirements, long-term channel statistics, the number of UEs, etc. Channel quality indicator (CQI) information received from the UEs is interpreted in different manners depending on the groups to which the UEs belong. A single UE may be selected at a time from the first group or multiple UEs may be selected at a time from the second group for MIMO transmission. A MIMO transmission may be sent to a single UE in the first group or multiple UEs in the second group at rates selected based upon the CQI information.