ARQ Resource Sharing for Link Capacity

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Solution Overview

Problem

Existing ARQ protocols face challenges in efficiently controlling transmission resources for re-transmissions, leading to reduced link capacity due to unpredictable error probabilities and increased control overhead and latency in both persistent and dynamic scheduling techniques.

Innovation Solution

A method that allocates shared transmission resources for re-transmissions among multiple ARQ processes, allowing for contention-based scheduling, where processes share resources initially and switch between re-transmissions to optimize resource utilization, while maintaining orthogonal initial transmissions to prevent collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If persistent scheduling is used to reserve transmission resources for re-transmissions in advance, then re-transmission opportunities are guaranteed, but transmission resources are wasted when re-transmissions are not needed and control overhead increases

Engineering Contradiction:
Improvere-transmission guaranteeVSAvoidtransmission resource waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements dynamic scheduling where the scheduler allocates re-transmission resources on-demand based on actual channel conditions and error rates, rather than statically reserving resources. This allows the system to adapt resource allocation to actual needs, preventing waste while ensuring re-transmissions can occur when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes scheduling parameters dynamically based on channel quality indicators and packet error rates. When error rates are low, fewer re-transmission resources are allocated; when error rates increase, more resources are dynamically assigned, optimizing the balance between reliability and resource efficiency.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If dynamic scheduling is used to allocate re-transmission resources on-demand, then transmission resource efficiency improves, but control overhead and latency increase due to continuous scheduling signaling

Engineering Contradiction:
Improvetransmission resource efficiencyVSAvoidcontrol signaling latency
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent pre-allocates a pool of re-transmission resources that can be quickly assigned without extensive scheduling signaling. When a packet error occurs, the system can rapidly grant re-transmission resources from the pre-configured pool, reducing the latency associated with dynamic resource allocation while maintaining efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains a reserved pool of re-transmission resources that is larger than the minimum expected need, allowing rapid allocation without detailed scheduling negotiations. This partial reservation approach reduces control overhead while ensuring sufficient resources are available for re-transmissions.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If orthogonal transmission resources are allocated to each ARQ process, then collision-free transmission is achieved, but link capacity is reduced due to underutilization of transmission resources

Engineering Contradiction:
Improvecollision-free transmissionVSAvoidlink capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple ARQ processes to share common re-transmission resources. When multiple processes need re-transmission, they can share the same time-frequency resources with appropriate multiplexing, increasing resource utilization and link capacity while maintaining collision-free operation through coordinated scheduling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates universal re-transmission resource pools that can serve multiple ARQ processes, rather than dedicating separate resources to each process. This multi-functional resource allocation increases overall link capacity by allowing the same resources to be reused across different ARQ processes as needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If shared transmission resources are allocated for re-transmissions among multiple ARQ processes, then link capacity and resource utilization improve, but collision risk increases without proper scheduling control

Engineering Contradiction:
Improveresource utilizationVSAvoidcollision risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where the scheduler monitors channel conditions, packet error rates, and resource utilization for each ARQ process. This feedback information is used to dynamically adjust resource allocation and scheduling decisions, preventing collisions by identifying and resolving resource conflicts before they occur while maintaining high resource utilization.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2017997B1Method and device for controlling transmission resources for automatic repeat request processes
Publication Date: 2010.10.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2017997B1 patent drawingFigure 1~2A
  • EP2017997B1 patent drawingFigure 2B
  • EP2017997B1 patent drawingFigure 3~4

AI summary

A method for controlling transmission resources for transmission and re-transmission of packets of a plurality of automatic repeat request processes comprises allocating, for each of the plurality of automatic repeat request processes, a transmission resource for transmission of a packet of the automatic repeat request process. The method further comprises allocating transmission resources as one or more re-transmission opportunities for re-transmission of the packet of at least two of the automatic repeat request processes such that at least two of the at least two automatic repeat request processes share transmission resource for at least one of the re-transmission opportunities. The method also comprises transmitting at least one control message indicating the allocated transmission resources. An electronic device for controlling transmission and re-transmission of packets of a plurality of automatic repeat request processes is also described.