HARQ Scheduling for Carrier Aggregation Devices

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Solution Overview

Problem

In wireless communication networks, bundled HARQ acknowledgments can lead to unnecessary retransmission of all HARQ subpackets when one subpacket is not properly received, wasting resources since properly received subpackets are retransmitted unnecessarily.

Innovation Solution

Implementing a HARQ transmission schedule that differentiates between data slots with bundled and unbundled acknowledgments, preferentially scheduling transmissions to WCDs supporting carrier aggregation in slots with bundled acknowledgments and to those without carrier aggregation in slots without bundling, thereby reducing unnecessary retransmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If bundled HARQ acknowledgments are used to accommodate asymmetric traffic patterns in TDD channels, then the system can handle more forward-direction traffic, but all HARQ subpackets in a group must be retransmitted even when only one is not properly received, wasting resources

Engineering Contradiction:

Improveforward-direction traffic capacityVSAvoidretransmission resource waste

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent segments the HARQ acknowledgment process by creating separate acknowledgment groups for different WCDs based on their carrier aggregation capabilities. WCDs with carrier aggregation support are assigned to bundled acknowledgment groups, while WCDs without this capability are assigned to unbundled groups. This segmentation allows the system to maintain bundled acknowledgments for traffic efficiency while avoiding unnecessary retransmissions for devices that cannot utilize carrier aggregation benefits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different acknowledgment bundling strategies to different local contexts (individual WCDs) based on their specific capabilities. Instead of applying bundled acknowledgments uniformly to all WCDs, the system tailors the acknowledgment approach to each WCD's carrier aggregation support status, thereby optimizing resource utilization locally for each device while maintaining overall system productivity.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If bundled HARQ acknowledgments are used, then fewer reverse-direction data slots are needed, but properly received subpackets are retransmitted unnecessarily, reducing transmission efficiency

Engineering Contradiction:

Improvereverse-direction data slotsVSAvoidtransmission efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent segments the WCD population into two distinct groups based on carrier aggregation capability. This segmentation enables the system to apply bundled acknowledgments only to WCDs that can benefit from carrier aggregation, thereby maintaining transmission efficiency while still reducing the number of reverse-direction data slots needed for acknowledgments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of acknowledgment bundling applicability based on the WCD's carrier aggregation capability. By dynamically determining which WCDs receive bundled acknowledgments versus individual acknowledgments, the system optimizes the balance between reducing reverse-direction slot requirements and maintaining transmission efficiency.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If HARQ acknowledgments are bundled such that a single acknowledgment serves multiple subpackets, then the acknowledgment process is more efficient, but when one subpacket is not properly received, all subpackets in the group must be retransmitted

Engineering Contradiction:

Improveacknowledgment process efficiencyVSAvoidretransmitted data

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The patent segments the acknowledgment process into bundled and unbundled groups based on WCD capabilities. This segmentation ensures that bundled acknowledgments are only applied to WCDs with carrier aggregation support, which can better handle the retransmission overhead, thereby maintaining acknowledgment efficiency while minimizing unnecessary data retransmission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different acknowledgment bundling quality levels to different WCDs based on their carrier aggregation capabilities. WCDs with carrier aggregation receive bundled acknowledgments (higher efficiency, acceptable retransmission overhead), while WCDs without this capability receive individual acknowledgments (lower efficiency but no unnecessary retransmissions), optimizing the trade-off for each device.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9445344B1Preferentially assigning data slots subject to bundled acknowledgments to devices that support carrier aggregation

Publication Date: 2016.09.13 SPRINT SPECTRUM LLC

AI summary

It may be determined that a hybrid automatic repeat request (HARQ) transmission schedule from a radio access network (RAN) to wireless communication devices (WCDs) uses HARQ acknowledgment bundling for a first set of two or more data slots, and that the HARQ transmission schedule does not use HARQ acknowledgment bundling for a second set of one or more data slots. It may further be determined that a first WCD supports carrier aggregation when receiving communications from the RAN, and that a second WCD does not support carrier aggregation when receiving communications from the RAN. Based on the first WCD supporting carrier aggregation, the RAN may transmit a first data to the first WCD in the first set of data slots. Based on the second WCD not supporting carrier aggregation, the RAN may transmit a second data to the second WCD in the second set of data slots.