LTE TDD Frame Structure HARQ-ACK Timing Simplification

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Solution Overview

Problem

The existing Long Term Evolution (LTE) TDD system has different HARQ-ACK timing for various uplink-downlink configurations, leading to increased complexity and making it difficult for different configurations to coexist effectively.

Innovation Solution

A method and system where user equipment determines a frame structure with specific subframe configurations, ensuring consistent HARQ-ACK timing across different uplink-downlink configurations by adjusting the number of symbols for downlink and uplink transmissions in each subframe, allowing the system to coexist with existing TDD systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different HARQ-ACK timing are used for different uplink-downlink configurations in TDD system, then each configuration can be optimized for its specific traffic pattern, but the system complexity increases and different configurations become difficult to coexist

Engineering Contradiction:

Improveadaptability to different uplink-downlink configurationsVSAvoidHARQ-ACK timing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by establishing a unified HARQ-ACK timing mechanism that works across all TDD uplink-downlink configurations. Instead of having configuration-specific timing rules, the system uses a universal timing approach where HARQ-ACK for PDSCH in subframe n-k is always feedback in subframe n, regardless of the specific uplink-downlink configuration. This allows the same timing mechanism to serve multiple configurations, reducing complexity while maintaining adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the parameter of HARQ-ACK timing from being configuration-dependent to being configuration-independent. By adjusting the timing parameter k to be fixed rather than variable across configurations, the system achieves simpler timing rules. The invention modifies the feedback timing parameter to resolve the contradiction between adaptability and complexity.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If traditional TDD frame structure with different HARQ-ACK timing for various configurations is used, then existing systems can be supported, but the feedback volume increases and processing complexity increases

Engineering Contradiction:

Improvecompatibility with existing TDD systemsVSAvoidfeedback volume

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges the HARQ-ACK feedback for multiple downlink subframes into a single uplink subframe. Instead of having separate feedback mechanisms for different configurations, the invention combines all HARQ-ACK feedbacks into a unified timing structure. This merging reduces the total feedback volume and processing complexity while maintaining compatibility with existing TDD systems through the use of standard PHICH and PUCCH/PUSCH channels.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses universality by creating a feedback mechanism that serves all uplink-downlink configurations simultaneously. The unified HARQ-ACK timing allows the same feedback procedure to handle multiple configurations, reducing the need for separate feedback processes for each configuration and thereby reducing overall feedback volume and processing requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If fixed HARQ-ACK timing is used for all configurations, then system complexity is reduced, but the ability to optimize for different traffic patterns is lost

Engineering Contradiction:

ImproveHARQ-ACK timing simplicityVSAvoidoptimization for different traffic patterns

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent achieves universality by designing a HARQ-ACK timing mechanism that is both simple and adaptable. The fixed timing rule (feedback in subframe n for PDSCH in subframe n-k) provides simplicity, while the mechanism remains adaptable because it works for all uplink-downlink configurations without requiring changes. This universal approach allows the system to maintain simplicity while preserving the ability to handle different traffic patterns through the existing flexible TDD configuration options.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10587337B2Information sending and receiving method and system, base station, and first user equipment

Publication Date: 2020.03.10 HUAWEI TECH CO LTD

AI summary

The present invention discloses a method, including: determining, by first user equipment, a frame structure of a first serving cell; and sending and receiving, by the first user equipment in the first serving cell, information based on the frame structure of the first serving cell, where: in the frame structure of the first serving cell, one radio frame includes at least one first subframe and at least one second subframe, and both the first subframe and the second subframe include a symbol used for downlink transmission, a guard period, and a symbol used for uplink transmission; in the first subframe, a quantity of symbols used for downlink transmission is greater than a quantity of symbols used for uplink transmission; and in the second subframe, a quantity of symbols used for downlink transmission is less than a quantity of symbols used for uplink transmission.