Uplink Control Information Reporting Mode Selection for Carrier Aggregation

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Solution Overview

Problem

In 3GPP LTE Rel-10 carrier aggregation, Channel State Information (CSI) reports often get dropped due to collisions with HARQ-ACK or when multiple reports occur in the same sub-frame, leading to inefficient use of resources and potential loss in downlink throughput.

Innovation Solution

A method for selecting and transmitting CSI and HARQ-ACK reports using various reporting modes based on payload size and multiplexing with uplink data, optimizing resource usage by choosing smaller payload sizes when reports are multiplexed with data and larger sizes when transmitted alone, to minimize dropping and maximize resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple CSI reports are transmitted periodically on PUCCH, then CSI feedback coverage is improved, but resource collisions cause CSI reports to be dropped

Engineering Contradiction:

ImproveCSI feedback delivery reliabilityVSAvoidresource utilization efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic selection between two reporting modes (Mode 1 for PUCCH, Mode 2 for PUSCH) based on real-time channel conditions and resource availability. The system transitions from static periodic reporting to adaptive reporting that dynamically adjusts the transmission channel and payload size according to current system state, thereby avoiding collisions and improving both reliability and efficiency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters including payload size (reducing to 20 bits when multiplexed with data), reporting channel (switching between PUCCH and PUSCH), and reporting frequency (adjusting based on UL data presence). These parameter changes allow the system to adapt to different traffic conditions and avoid resource collisions that cause CSI dropping

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If PUSCH is used to carry periodic CSI reports, then more comprehensive CSI feedback can be transmitted, but resource allocation inefficiency occurs due to large PRB size relative to small CSI payload

Engineering Contradiction:

ImproveCSI information volumeVSAvoidresource allocation complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies partial action by transmitting only the essential CSI payload (reduced to 20 bits when multiplexed) on PUSCH rather than using full aperiodic reporting formats. This partial transmission approach avoids allocating excessive resources while still providing sufficient CSI feedback for system operation

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent makes the PUSCH serve multiple functions: it can carry UL data alone, or multiplexed with CSI reports and/or HARQ-ACK. The same physical resource block is universally used for different combinations of uplink transmissions, improving resource utilization efficiency while maintaining the ability to transmit comprehensive CSI when needed

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If aperiodic CSI reporting is requested individually via DCI, then comprehensive CSI feedback is obtained, but significant overhead is generated on PDCCH

Engineering Contradiction:

ImproveCSI feedback accuracyVSAvoidcontrol signaling overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent implements periodic CSI reporting on PUSCH for Mode 2, replacing individual aperiodic requests with scheduled periodic transmissions. This reduces PDCCH overhead by eliminating repeated DCI-based CSI requests while maintaining comprehensive CSI feedback through configured periodic reports that occur at regular intervals

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent reuses existing periodic reporting modes and formats for the new PUSCH-based periodic CSI reporting, rather than creating entirely new aperiodic reporting mechanisms. This copying approach leverages existing standardized formats to reduce overhead while maintaining CSI accuracy

Inventive Principle:

Principle #26Copying

4Productivity

If CSI payload size is increased for comprehensive feedback, then downlink throughput improvement is achieved, but resource efficiency decreases when multiplexed with UL data

Engineering Contradiction:

Improvedownlink throughputVSAvoiduplink resource consumption

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent dynamically adjusts CSI payload size based on whether UL data is present: using reduced payload (20 bits) when multiplexed with data to minimize uplink resource consumption, and full payload when transmitted alone to maximize downlink throughput feedback accuracy

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the CSI payload size parameter according to transmission conditions, switching between compact and comprehensive reporting formats. This parameter adaptation allows the system to optimize the balance between downlink throughput improvement and uplink resource efficiency in different operating scenarios

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9538509B2Method and apparatus for multi-mode control information on uplink channel

Publication Date: 2017.01.03 ALCATEL LUCENT SA

AI summary

One embodiment includes a method for selecting, by a mobile unit, one of a plurality of control information reporting modes based on at least one of a control information transmission type and a payload size. The method further includes transmitting, by the mobile unit, one or more UCI report(s) to the base station using the selected UCI reporting mode.