Dynamic TDD Signaling via Explicit Messages for UE Power Reduction

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Solution Overview

Problem

In dynamic Time Division Duplex (TDD) systems, user equipment (UE) faces challenges in determining when to receive downlink signals and when to signal Hybrid Automatic Repeat Request (HARQ) information, particularly due to the use of flexible subframes that can be assigned as either uplink or downlink, leading to increased power consumption and potential false detections.

Innovation Solution

The implementation of explicit signaling messages by the network node to indicate specific subframes for downlink signal reception and HARQ information transmission, complemented by a semi-static TDD reference configuration for reliable HARQ timing, reduces unnecessary power consumption and improves Channel State Information (CSI) measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible subframes are used in dynamic TDD systems to adapt to traffic demands, then system adaptability is improved, but UE power consumption increases and false detections occur

Engineering Contradiction:

Improvesystem adaptabilityVSAvoidUE power consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent introduces an intermediary mechanism (explicit signaling messages) that mediates between the flexible subframe configuration and the UE's monitoring behavior. The network node sends explicit signaling to indicate whether a flexible subframe should be monitored for downlink signals, allowing the UE to adjust its monitoring behavior accordingly, thus reducing unnecessary power consumption while maintaining system adaptability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies dynamics by making the monitoring configuration dynamic rather than static. The UE's monitoring behavior is dynamically adjusted based on explicit signaling messages received from the network node, allowing the system to adapt to changing traffic conditions while optimizing power consumption by monitoring only when necessary.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If flexible subframes are dynamically assigned as uplink or downlink, then system adaptability is improved, but HARQ timing reliability deteriorates

Engineering Contradiction:

Improvesystem adaptabilityVSAvoidHARQ timing reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the TDD configuration into two parts: a semi-static reference configuration that provides reliable HARQ timing information, and dynamic flexible subframe assignments that adapt to traffic demands. The UE uses the semi-static reference configuration to determine HARQ timing, ensuring reliability, while the dynamic assignments provide adaptability for traffic optimization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The semi-static TDD reference configuration acts as an intermediary that provides stable HARQ timing information regardless of the dynamic flexible subframe assignments. This intermediary mechanism ensures that HARQ timing remains reliable even when the actual subframe directions are dynamically changed for traffic optimization.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If UE monitors all flexible subframes for downlink signals, then measurement accuracy is improved, but power consumption increases

Engineering Contradiction:

ImproveCSI measurement accuracyVSAvoidUE power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The explicit signaling message from the network node serves as an intermediary that provides information about which flexible subframes should be monitored for downlink signals. This allows the UE to selectively monitor only the necessary subframes, maintaining CSI measurement accuracy while significantly reducing power consumption by avoiding unnecessary monitoring of all flexible subframes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of the UE monitoring all flexible subframes (excessive action), the patent enables partial monitoring by using explicit signaling to indicate only the specific flexible subframes that should be monitored. This partial action approach maintains measurement accuracy for relevant subframes while reducing overall power consumption.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10541789B2Methods and apparatuses for signaling in dynamic time division duplex systems

Publication Date: 2020.01.21 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present invention relates to a method in a UE served by a network node, a method in the network node, the UE, and the network node. The network node is applying dynamic TDD with flexible subframes. The method comprises receiving a first configuration message from the network node indicating a TDD reference configuration, and determining in which subframe to signal HARQ information based on the TDD reference configuration. The method further comprises receiving a second configuration message from the network node indicating a set of DL subframes that may comprise explicit signaling messages, monitoring the indicated set of DL subframes, and receiving an explicit signaling message in response to monitoring. The explicit signaling message designates a subframe in which the UE shall receive a DL signal. The method also comprises preparing to receive the DL signal in the designated subframe.