HARQ Process Signaling Without Larger DCI Fields

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Solution Overview

Problem

Existing wireless communication systems face challenges in managing Hybrid Automatic Repeat Request (HARQ) feedback, particularly in scenarios with long round-trip times, leading to inefficiencies and delays, and there is a need for improved methods to disable HARQ feedback reliably and optimize HARQ processes without increasing the bit field size in Downlink Control Information (DCI).

Innovation Solution

The implementation of a wireless device configured to receive multiple sets of HARQ process numbers, enabling semi-static and dynamic control of HARQ feedback through Radio Resource Control (RRC) and Medium Access Control (MAC) messages, along with DCI signaling using RNTI and field reinterpretation, to manage HARQ processes effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If HARQ feedback is enabled for all HARQ processes, then reliability of data transmission is improved, but delay increases due to long round-trip times

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidround-trip time delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making HARQ feedback configurable rather than static. The network can dynamically enable or disable HARQ feedback for specific HARQ processes based on service requirements, allowing the system to adapt between reliable but slow feedback modes and faster feedback-less modes depending on the transmission scenario.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of HARQ feedback status from a fixed state to a configurable state. By introducing configuration messages that can enable or disable HARQ feedback for different HARQ processes, the system can adjust the feedback parameter to optimize between reliability and delay for different service types.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If HARQ process numbers are increased to support more processes, then adaptability is improved, but DCI bit field size increases

Engineering Contradiction:
ImproveHARQ process support capabilityVSAvoidDCI bit field size
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the HARQ process space by introducing two separate indication mechanisms: one for indicating which HARQ process is being referred to, and another for indicating whether feedback is enabled or disabled for that process. This segmentation allows the system to support more HARQ processes without proportionally increasing the bit field size for process identification.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds another dimension to the DCI structure by including a separate feedback enable/disable indication alongside the HARQ process number. This dimensional addition allows the system to encode feedback status information without expanding the core HARQ process identification field, effectively increasing adaptability without proportional complexity increase.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3866368B1HARQ design for wireless communications
Publication Date: 2025.07.02 APPLE INC
  • EP3866368B1 patent drawingFigure 1
  • EP3866368B1 patent drawingFigure 2
  • EP3866368B1 patent drawingFigure 3

AI summary

A user equipment, UE, baseband processor and method comprising receiving (1202) a first set and a second set of hybrid automatic repeat request (HARQ) process numbers, the first set and the second set of HARQ process numbers corresponding to a first set and a second set of HARQ processes respectively; receiving (1204) a downlink control information (DCI), wherein a radio network temporary identifier (RNTI) is scrambled with cyclic redundancy check (CRC) bits of the DCI; and determining (1206) a HARQ process number in the first set or the second set of HARQ process numbers based on at least one of the RNTI (1208, 1210) or a field in the DCI (1212, 1214). This enables HARQ optimization by increasing HARQ process numbers without increasing a bit field size of "HARQ process number" in DCI.