Selective ACK/NACK Reporting for D2D Scheduling Overhead

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Solution Overview

Problem

Current wireless communication systems, particularly in LTE technology, face challenges in efficiently exchanging control information for device-to-device (D2D) scheduling, leading to resource assignment overhead and inaccurate ACK/NACK reporting.

Innovation Solution

Implementing selective ACK/NACK reporting mechanisms, where the receiver sends ACKs only to the eNB for successful receptions and NACKs only to the transmitter, with optional direct air transmission for D2D links far from other devices, to minimize resource assignment overhead and improve scheduling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If selective ACK/NACK reporting is implemented where receiver sends ACK only to eNB and NACK only to transmitter, then resource assignment overhead is reduced, but system complexity increases due to differentiated reporting paths

Engineering Contradiction:
Improveresource assignment overheadVSAvoidscheduling mechanism complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent segments the ACK/NACK feedback mechanism into two distinct paths: successful receptions (ACK) are reported only to the eNB, while failed receptions (NACK) are reported only to the transmitter. This segmentation allows each path to be optimized independently, reducing overall resource assignment overhead while maintaining clear responsibility boundaries between eNB and transmitter devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The eNB acts as an intermediary that receives ACK reports from receivers and coordinates resource assignments. The eNB processes the selective reporting information and manages the centralized D2D scheduling, serving as a mediator between the transmitter and receiver devices to optimize resource allocation without requiring direct complex interaction between all devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If centralized D2D scheduling is implemented with selective ACK/NACK reporting, then scheduling efficiency is enhanced, but control information exchange complexity increases

Engineering Contradiction:
Improvescheduling efficiencyVSAvoidcontrol information exchange
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where receivers report ACK/NACK status to appropriate entities (eNB or transmitter) based on reception success. This feedback enables the centralized scheduler at the eNB to make informed scheduling decisions, improving scheduling efficiency by allocating resources based on actual transmission outcomes while maintaining structured control information flow.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Different reporting behaviors are assigned based on local conditions: successful receptions generate ACK reports to the eNB, while failed receptions generate NACK reports to the transmitter. This local quality differentiation optimizes the control information exchange by sending only necessary feedback to the appropriate entity, reducing overall system complexity.

Inventive Principle:
Principle #3Local quality

3Productivity

If ACK/NACK reporting is optimized for D2D links far from other devices, then system performance improves, but coverage area constraints are imposed

Engineering Contradiction:
Improvesystem performanceVSAvoidD2D link coverage area
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent applies dynamic resource assignment where the eNB adjusts D2D resource allocations based on real-time ACK/NACK feedback and distance considerations. For D2D links identified as being far from other devices, the system dynamically optimizes reporting paths and resource usage, improving performance for these specific scenarios while the eNB maintains overall coverage management for links in more congested areas.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2901597B1Scheduling assignment and ACK/NACK reporting to facilitate centralized d2d scheduling
Publication Date: 2017.06.14 QUALCOMM INC
  • EP2901597B1 patent drawingFigure 1
  • EP2901597B1 patent drawingFigure 2
  • EP2901597B1 patent drawingFigure 3

AI summary

A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus receives a resource assignment from a serving base station for a device-to-device (D2D) link with a transmitter, attempts to receive a data packet from the transmitter based on the resource assignment, sends an acknowledgment (ACK) only to the serving base station when reception of the data packet succeeds, and sends a negative acknowledgment (NACK) only to the transmitter when the reception of the data packet fails. In an aspect, the apparatus receives a resource assignment from a serving base station for a D2D link with a receiver, sends a data packet to the receiver based on the resource assignment, and assumes the data packet is successfully received at the receiver unless a NACK is received from the receiver, wherein the NACK indicates a failed reception of the data packet at the receiver.