Cross-Cell Scheduling for TDD Collision Avoidance

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Solution Overview

Problem

In TDD wireless access systems supporting carrier aggregation, the differing uplink-downlink configurations across carriers lead to data transmission or reception inefficiencies and collisions, particularly in cross-carrier scheduling scenarios, which affect the scheduling of uplink and downlink data transmission timing.

Innovation Solution

The method involves identifying potential collision subframes between different uplink and downlink configurations of aggregated carriers and adjusting the scheduling to avoid such collisions by changing the transmission timing based on the specific uplink-downlink configuration of each cell, allowing for efficient data transmission and reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cross carrier scheduling is performed with different uplink-downlink configurations per carrier, then bandwidth utilization and data transmission rate are improved, but collision between downlink of one carrier and uplink of another carrier occurs

Engineering Contradiction:
Improvedata transmission rateVSAvoiddata transmission reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by identifying potential collision subframes between different uplink-downlink configurations before actual data transmission occurs. The base station determines collision-free subframes in advance and configures appropriate uplink-downlink settings to prevent collisions, thereby maintaining both high data transmission rates and reliability without actual conflicts occurring during operation.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If each uplink-downlink configuration is provided per carrier, then adaptability to different traffic demands is improved, but scheduling complexity increases

Engineering Contradiction:
Improveconfiguration adaptabilityVSAvoidscheduling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by allowing different uplink-downlink configurations for different carriers based on their specific traffic demands and characteristics. Each carrier can be independently configured with appropriate uplink-downlink ratios, enabling localized optimization without requiring complex system-wide scheduling. This approach maintains configuration adaptability while reducing overall scheduling complexity through decentralized carrier-specific management.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2696523B1Method for transmitting/receiving data in a wireless access system and base station for same
Publication Date: 2018.10.03 LG ELECTRONICS INC
  • EP2696523B1 patent drawingFigure 1
  • EP2696523B1 patent drawingFigure 2(a)~2(b)
  • EP2696523B1 patent drawingFigure 3

AI summary

The present invention relates to a method for transmitting/receiving data in a Time Division Duplex (TDD) wireless access system supporting multiple cells, and a base station for same. In more detail, on the basis of a multi-cell TDD uplink-downlink configuration, the method includes confirming whether a collision subframe occurs, which is caused when an uplink subframe of a first cell and a downlink subframe of a second cell exists in the same time interval; and performing cross cell scheduling on the second cell through the first cell according to a TDD uplink-downlink configuration of the first cell. When data transmission is scheduled in the collision subframe by cross cell scheduling, by changing the transmission position of an uplink or a downlink according to the cross cell scheduling, the scheduled data are transmitted in the collision subframe.