Semi-Persistent Scheduling Sub-Frame Selection for HARQ Collision Avoidance

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Solution Overview

Problem

The existing semi-persistent scheduling method in LTE systems experiences timing collisions between HARQ retransmissions and data arrivals, leading to increased signaling overhead and inconsistent data arrival intervals, which necessitate buffering and dynamic scheduling reconfigurations.

Innovation Solution

A method where the eNB and UE select sub-frames from a sub-frame group with a periodicity matching the semi-persistent scheduling interval, allowing for different relative positions in subsequent groups to extend the timing collision interval and reduce resource collisions, thereby avoiding extra buffering and signaling overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the least common multiple of semi-persistent scheduling periodicity and HARQ RTT is small, then timing collision between HARQ retransmission and semi-persistent scheduling occurs frequently, but increasing the least common multiple by configuring a new periodicity causes data arrival interval inconsistency and requires upper layer buffering

Engineering Contradiction:
Improvecollision avoidanceVSAvoidbuffering delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent divides the semi-persistent scheduling periodicity into multiple sub-frame groups, where each group contains multiple sub-frames. By selecting different sub-frames from different groups for semi-persistent scheduling and HARQ retransmission respectively, the system segments the resource allocation in time domain, thereby avoiding timing collisions without requiring upper layer buffering.

Inventive Principle:
Principle #1Segmentation

2Productivity

If semi-persistent scheduling periodicity is configured to match data arrival interval, then data transmission efficiency is improved, but timing collision with HARQ retransmission occurs when least common multiple is small

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidtiming collision
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a new dimension of sub-frame group selection by configuring multiple sub-frames in each sub-frame group. Instead of only adjusting the periodicity value, the system selects different sub-frames from the group based on relative position parameters, adding a spatial dimension to the time-domain resource allocation and enabling collision avoidance while maintaining efficient periodicity matching.

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

Data Source

PatentEP2312883B1A semi-persistent scheduling method
Publication Date: 2015.04.01 ZTE CORP
  • EP2312883B1 patent drawingFigure 1
  • EP2312883B1 patent drawingFigure 2
  • EP2312883B1 patent drawingFigure 3

AI summary

A semi-persistent scheduling method is provided in the present disclosure, and the method comprises: when a semi-persistent scheduling periodicity comes, an evolved node B (eNB) and a terminal (UE) select a sub-frame in a sub-frame group as a sub-frame for current semi-persistent scheduling; the sub-frame group includes multiple sub-frames, and a sub-frame group periodicity equals to the semi-persistent scheduling periodicity. The problem that the sub-frames with the same relative position in different sub-frame groups are the sub-frames in which the collision between the initial transmission and the retransmission of the HARQ data packet most possibly occurs is considered by the technical solution of the present disclosure, so the purpose that prolonging the interval length of the collision between the initial transmission of the HARQ and the retransmission of the HARQ and reducing the collision between the initial transmission of the HARQ and the retransmission of the HARQ is achieved by reasonably configuring the number of sub-frames in a sub-frame group and alternately using different sub-frames in the sub-frame group.