Time Multiplexing Secondary Cell Transmissions in LAA-LTE

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Solution Overview

Problem

Current SCell channel selection schemes in LAA-LTE networks are inefficient due to dynamic channel usage, reliance on eNB for channel quality determination, and lack of granular selection based on user device feedback, leading to suboptimal performance.

Innovation Solution

Implementing time multiplexing of SCell transmissions and receptions, where network nodes determine and manage SCell activation and deactivation based on downlink buffer status and channel quality measurements from user devices, allowing each SCell to have variable transmission and reception periods within a communication cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If time multiplexing is implemented for SCell transmissions, then channel utilization and user experience are enhanced, but transmission time and system complexity increase

Engineering Contradiction:
Improvechannel utilizationVSAvoidtransmission time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements periodic action by establishing a communication cycle that repeatedly executes transmission routines for multiple SCells in sequence. Each SCell is transmitted during its designated time slot within each cycle, creating a periodic pattern that efficiently utilizes available spectrum resources while managing time constraints through cyclic repetition.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies segmentation by dividing the transmission schedule into distinct time slots, each dedicated to a specific SCell. This segmentation allows independent management of each SCell's transmission parameters and enables the network to optimize channel utilization by selectively activating SCells based on current traffic conditions and buffer status.

Inventive Principle:
Principle #1Segmentation

2Extent of automation

If eNB controls all SCell channel quality determination, then network control is centralized, but adaptability to localized user feedback is reduced

Engineering Contradiction:
Improvenetwork controlVSAvoidlocalized channel selection
Core Design Contradiction:
Extent of automationVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback mechanisms where user devices provide channel quality measurements and preferences back to the network node. This feedback loop enables the network to adapt SCell activation and transmission timing based on actual user experience and localized channel conditions, improving both adaptability and network control through iterative optimization.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by making SCell activation and transmission timing flexible rather than fixed. The network dynamically adjusts which SCells are active and when they transmit based on real-time buffer status, channel quality feedback, and traffic demands, allowing the system to adapt to changing conditions while maintaining centralized coordination.

Inventive Principle:
Principle #15Dynamics

3Productivity

If all SCells transmit simultaneously, then throughput is maximized, but channel quality measurements and interference management become difficult

Engineering Contradiction:
ImprovethroughputVSAvoidchannel quality measurement
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the transmission timeline into distinct time slots where each SCell transmits sequentially rather than simultaneously. This temporal segmentation allows the network to measure channel quality for each SCell independently during its dedicated slot, eliminating interference from other SCells and simplifying measurement while maintaining high throughput through efficient time-division multiplexing.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3254514B1Time multiplexing communication with secondary cells
Publication Date: 2020.04.08 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3254514B1 patent drawingFigure 1~2
  • EP3254514B1 patent drawingFigure 3
  • EP3254514B1 patent drawingFigure 4~5

AI summary

A method implemented by a network node of a cellular communication network serving a plurality of user devices is disclosed. The method comprises determining a transmission routine for each of a plurality of secondary cells (SCells) using radio channels in an unlicensed spectrum. Each transmission routine has an associated transmission period based on a downlink (DL) buffer status. The method also comprises time multiplexing transmission from the plurality of SCells to the plurality of user devices by executing the transmission routines for their respective time periods. Network nodes, apparatus, computer programs associated with the method are also disclosed.