TDD Uplink Indicator for Asymmetric Subframe Scheduling

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Solution Overview

Problem

In Time Division Duplexing (TDD) systems, accurate scheduling information transmission is challenging due to asymmetric subframe allocations and the need to clearly indicate specific subframes for uplink and downlink radio resource assignments, which affects efficient data transmission.

Innovation Solution

A method is introduced where a base station transmits an uplink indicator as downlink control information to specify the location of uplink subframes, ensuring accurate allocation of radio resources for user equipment, using a format that includes an uplink indicator to indicate valid uplink subframes within the TDD system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If asymmetric subframe allocation is used in TDD system, then adaptability to asymmetric services is improved, but scheduling information transmission accuracy deteriorates

Engineering Contradiction:
Improveadaptability to asymmetric servicesVSAvoidscheduling information transmission accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The scheduling information is segmented into two parts: a common part containing downlink resource assignment applicable to all uplink subframes, and a specific part containing uplink indicator that identifies which specific uplink subframe the scheduling applies to. This segmentation allows the system to maintain asymmetric subframe allocation while accurately indicating the specific subframe for scheduling, thus resolving the contradiction between adaptability and accuracy.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If new scheduling information transmission method is introduced, then scheduling accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvescheduling accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The uplink indicator is merged with the downlink resource assignment in a single scheduling message. The uplink indicator fields are incorporated into the existing downlink resource assignment structure, allowing the base station to transmit both the resource assignment and the specific uplink subframe indication in one unified message, thereby improving scheduling accuracy without significantly increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2975796B1Method of transmitting scheduling information in TDD system
Publication Date: 2020.06.10 INTERDIGITAL PATENT HOLDINGS INC
  • EP2975796B1 patent drawingFigure 1~2
  • EP2975796B1 patent drawingFigure 3
  • EP2975796B1 patent drawingFigure 4

AI summary

A method of transmitting, by a base station, scheduling information in a time-division-duplex (TDD) mobile communication system using a plurality of radio frames that each include downlink subframes reserved for downlink and uplink subframes reserved for uplink is proposed. The method comprises the transmitting, to a user equipment, scheduling information on a downlink control channel within a downlink subframe in a radio frame, the scheduling information comprising information on a position of at least one uplink subframe for which uplink resource is assigned from a position of the downlink subframe, information on a number of the at least one uplink subframe, and an uplink resource assignment. The uplink resource assignment identifies a radio resource to be used for uplink data transmission in the at least one uplink subframe, and a number of downlink subframes in the radio frame is less than a number of uplink subframes in the radio frame.