Wireless Device Downlink Control Channel Monitoring in TDD CoMP

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Solution Overview

Problem

In a Coordinated Multi Point (CoMP) scenario, wireless devices served by multiple transmission points face challenges in determining the correct subframes for downlink control channel monitoring due to conflicting uplink-downlink configurations, leading to potential missed control information and impaired channel quality measurements.

Innovation Solution

A wireless device method and system that receive and monitor downlink control channels in all indicated downlink subframes not assigned for uplink transmission, ensuring consistent monitoring across different uplink-downlink configurations from multiple transmission points, thereby minimizing the risk of missing control information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wireless device monitors downlink control channels in all possible downlink subframes indicated by multiple uplink-downlink configurations, then the reliability of receiving control information is improved, but the device complexity increases

Engineering Contradiction:

Improvecontrol information reception reliabilityVSAvoidmonitoring complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The wireless device dynamically adapts its monitoring behavior by identifying conflicting subframes between multiple uplink-downlink configurations and adjusting monitoring actions accordingly. The device determines which subframes are actually needed for monitoring based on the specific conflict pattern, rather than statically monitoring all possible subframes or using a fixed monitoring pattern.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The monitoring pattern parameters are changed based on the detected configuration conflicts. The device modifies monitoring behavior by identifying subframes that are downlink in at least one configuration but uplink in another, and adjusts monitoring to focus on these critical conflicting subframes rather than all downlink subframes uniformly.

Inventive Principle:

Principle #35Parameter changes

2Loss of information

If the wireless device monitors downlink control channels in all indicated downlink subframes, then the loss of information is reduced, but the use of energy increases

Engineering Contradiction:

Improvecontrol information lossVSAvoiddevice energy consumption

Core Design Contradiction:

Loss of informationVSUse of energy by moving object

Solution Approach 1:

The wireless device extracts and identifies only the critical conflicting subframes that require monitoring, separating them from the set of all possible downlink subframes. By taking out only the necessary monitoring targets (subframes with configuration conflicts) rather than monitoring all downlink subframes, the device reduces energy consumption while preventing control information loss.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of monitoring all possible downlink subframes (excessive action), the device performs partial monitoring only in the conflicting subframes where control information might be missed. This partial action is sufficient to prevent information loss while avoiding the energy waste of monitoring unnecessary subframes.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If the wireless device uses multiple uplink-downlink configurations for CoMP operation, then the adaptability of the network is improved, but the difficulty of detecting and measuring control channels increases

Engineering Contradiction:

Improvenetwork configuration adaptabilityVSAvoidcontrol channel detection difficulty

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The wireless device segments the set of downlink subframes into different categories based on the uplink-downlink configurations: conflicting subframes (downlink in at least one config but uplink in another), consistent downlink subframes, and uplink subframes. This segmentation allows the device to apply different detection strategies to each segment, simplifying the overall detection process while maintaining support for multiple configurations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The device uses the uplink-downlink configuration information itself as an intermediary to resolve the detection difficulty. By analyzing the configuration patterns and identifying conflicting subframes, the device creates a simplified monitoring rule set that mediates between the multiple configurations, making control channel detection manageable despite the complexity of supporting multiple CoMP transmission points.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10014912B2Method and wireless device for monitoring a downlink control channel

Publication Date: 2018.07.03 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method and a wireless device for operating in a Coordinated Multi Point (CoMP) scenario where the wireless device is served by at least two transmission points of a wireless network employing Time Domain Duplex (TDD). The wireless device receives at least two different uplink-downlink configurations which are valid for corresponding transmission points of the at least two transmission points. The wireless device further monitors a downlink control channel in all possible downlink subframes indicated by the received uplink-downlink configurations and not being assigned with uplink transmission for the wireless device, such that the wireless device monitors the downlink control channel in subframes being indicated as downlink by at least one of the different uplink-downlink configurations.