DCI Type Segmentation for Shortened TTI Latency Reduction

Solution Overview

Problem

Current wireless communication technologies face challenges in reducing latency, particularly in the transmission time interval (TTI) length, which affects the efficiency of downlink control information (DCI) and user throughput, especially with the introduction of shortened TTI (sTTI) concepts that require complex DCI designs to differentiate between normal and shortened TTI scheduling.

Innovation Solution

The proposed solution involves a DCI design that differentiates between normal and shortened TTI scheduling by using distinct types of DCI (first, second, and third types) transmitted in specific OFDM symbol durations, allowing for the reduction of blind decoding times and simplifying user equipment detection complexity by transmitting appropriate DCI types in corresponding TTI durations within a subframe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If shortened TTI is introduced to reduce latency, then transmission time is reduced, but DCI design complexity increases

Engineering Contradiction:

Improvetransmission timeVSAvoidDCI design complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The DCI is segmented into multiple types (first type for normal TTI, second type for shortened TTI, third type for additional shortened TTI) based on the scheduling requirements. Each DCI type contains specific fields appropriate for its purpose, allowing the system to reduce latency through shortened TTI while managing complexity through structured segmentation of control information.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically selects which DCI type to transmit based on whether normal TTI or shortened TTI needs to be scheduled. The base station circuitry determines the appropriate DCI type dynamically, and the transmitter sends the corresponding DCI. This dynamic adaptation allows the system to optimize performance for different scheduling scenarios without requiring the UE to always process all possible DCI types.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple DCI types are used to differentiate scheduling, then scheduling flexibility improves, but user equipment detection complexity increases

Engineering Contradiction:

Improvescheduling flexibilityVSAvoidUE detection complexity

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The DCI is segmented into multiple types (first type for normal TTI, second type for shortened TTI, third type for additional shortened TTI) based on the scheduling requirements. Each DCI type contains specific fields appropriate for its purpose, allowing the system to reduce latency through shortened TTI while managing complexity through structured segmentation of control information.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base station circuitry determines in advance which DCI type should be transmitted based on the scheduling decision. By preparing and selecting the appropriate DCI type before transmission, the system ensures that the UE can efficiently detect and process the DCI without having to parse multiple possible types, thereby reducing detection complexity while maintaining scheduling flexibility.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If blind decoding of sPDCCH candidates is performed in each sTTI, then scheduling precision improves, but processing time increases

Engineering Contradiction:

Improvescheduling precisionVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The base station circuitry determines in advance which DCI type should be transmitted based on the scheduling decision. By preparing and selecting the appropriate DCI type before transmission, the system ensures that the UE can efficiently detect and process the DCI without having to parse multiple possible types, thereby reducing detection complexity while maintaining scheduling flexibility.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically selects which DCI type to transmit based on whether normal TTI or shortened TTI needs to be scheduled. The base station circuitry determines the appropriate DCI type dynamically, and the transmitter sends the corresponding DCI. This dynamic adaptation allows the system to optimize performance for different scheduling scenarios without requiring the UE to always process all possible DCI types.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3455964B1User equipment for detecting DCI types within a subframe

Publication Date: 2022.01.19 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

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AI summary

Provided are base stations, user equipments and wireless communication methods related to DCI design for latency reduction. A base station comprises: circuitry operative to form either a first type of DCI or a second type of DCI depending on whether to schedule a normal TTI or a shortened TTI in a subframe; and a transmitter operative to transmit the first type of DCI or the second type of DCI in the subframe, wherein the first type of DCI and the second type of DCI are differentiable; and if the second type of DCI is transmitted and another shortened TTI is to be scheduled, the circuitry is further operative to form a third type of DCI and the transmitter is further operative to transmit the third type of DCI in a shortened TTI after said shortened TTI that is scheduled by the second type of DCI in the subframe.