Downlink ACK/NACK Indicator for LTE HARQ Synchronization

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Solution Overview

Problem

In LTE wireless communication networks, the lack of data-associated signaling in uplink transmission prevents base stations from accurately determining whether a mobile station is performing new data or retransmission, leading to synchronization issues and incorrect HARQ combination.

Innovation Solution

The method involves the base station sending an ACK/NACK packet with a transmission type indicator and resource use command in the downlink, allowing the mobile station to perform new data or retransmission operations without using uplink data-associated signaling, thus maintaining synchronization and minimizing downlink signaling overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If data-associated signaling is used in uplink transmission, then the base station can accurately determine whether a mobile station is performing new data or retransmission, but the signaling overhead increases

Engineering Contradiction:

Improvebase station's ability to determine transmission typeVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts the transmission type indication function from uplink data-associated signaling and relocates it to downlink ACK/NACK packets. The base station determines whether the mobile station should perform new data transmission or retransmission, and conveys this information through the downlink ACK/NACK packet, thereby eliminating the need for uplink data-associated signaling while maintaining accurate transmission type determination

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of having the mobile station indicate transmission type to the base station through uplink signaling, the patent inverts the approach by having the base station determine and communicate the transmission type to the mobile station through downlink signaling. This inversion eliminates uplink data-associated signaling while achieving the same functional objective

Inventive Principle:

Principle #13The other way round (Inversion)

2Quantity of substance

If uplink data-associated signaling is eliminated, then signaling overhead is reduced, but synchronization between base station and mobile station becomes difficult to maintain

Engineering Contradiction:

Improvesignaling overheadVSAvoidsynchronization between base station and mobile station

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent establishes a feedback mechanism where the base station sends ACK/NACK packets with transmission type indicators to the mobile station. The mobile station receives this feedback and adjusts its transmission accordingly, maintaining synchronization without requiring uplink data-associated signaling. The feedback loop ensures both parties remain synchronized on transmission type and resource allocation

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The downlink ACK/NACK packet serves as an intermediary that carries transmission type indication information from the base station to the mobile station. This intermediary mechanism enables synchronization maintenance without direct uplink signaling from the mobile station, resolving the contradiction between reduced overhead and synchronization stability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the base station uses common Maximum HARQ retransmission number for all radio bearers, then device complexity is reduced, but adaptability to different service requirements decreases

Engineering Contradiction:

ImproveHARQ configuration complexityVSAvoidadaptability to different radio bearers

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by allowing different Maximum HARQ retransmission numbers for different radio bearers based on their specific service requirements. Each radio bearer can be configured with appropriate HARQ parameters tailored to its QoS needs, such as setting higher retransmission limits for delay-tolerant services and lower limits for real-time services, thereby achieving adaptability without excessive complexity

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10110351B2Communication method and apparatus for controlling data transmission and retransmission of mobile station at base station

Publication Date: 2018.10.23 NOKIA TECHNOLOGIES OY

AI summary

Disclosed is a communication method for controlling data transmission of a mobile station at a base station. The method comprises the steps of: determining, by the base station, a transmission operation to be performed by the mobile station in next transmission time interval based on HARQ and schedule result; sending, in a downlink by the base station, an ACK/NACK packet, an indicator indicating the type of the transmission by the mobile station and a resource use command for the used resource based on the determined transmission operation; receiving, by the mobile station, the ACK/NACK packet, the indicator and the resource use command sent from the base station, and performing respective transmission operations according to the received ACK/NACK packet, indicator and resource use command without using any data-associated signaling in an uplink.