Multiplexing CSI and HARQ-ACK via Joint Coding

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Solution Overview

Problem

In the 3GPP LTE-A standard, there is a conflict when channel state information (CSI) and hybrid automatic repeat request-acknowledgement (HARQ-ACK) information are transmitted in the same subframe, leading to frequent dropping of CSI, which results in downlink throughput loss due to unavailability of proper CSI feedback.

Innovation Solution

The solution involves multiplexing CSI and HARQ-ACK information using Reed-Muller coding and tailbiting convolutional coding, allowing joint coding and transmission on PUCCH format 2 resources, or discarding CSI bits and transmitting HARQ-ACK information using PUCCH format 1b with channel selection when the number of UCI bits exceeds the payload capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CSI and HARQ-ACK information are transmitted in the same subframe using separate PUCCH formats, then both information types can be transmitted independently, but resource collision occurs leading to frequent CSI dropping

Engineering Contradiction:

ImproveCSI transmission reliabilityVSAvoidPUCCH resource management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines CSI and HARQ-ACK information into a single PUCCH format 2 transmission by multiplexing the bit streams together. This merging approach eliminates resource collision between separate PUCCH formats and ensures both information types are transmitted reliably in the same subframe without dropping CSI.

Inventive Principle:

Principle #5Merging (Combining)

2Loss of information

If joint coding of CSI and HARQ-ACK is implemented, then resource collision is avoided and CSI dropping is reduced, but the payload capacity constraint of PUCCH format 2 limits the total number of bits that can be transmitted

Engineering Contradiction:

ImproveCSI dropping lossVSAvoidUCI payload capacity

Core Design Contradiction:

Loss of informationVSQuantity of substance

Solution Approach 1:

When the total number of UCI bits exceeds the PUCCH format 2 payload capacity, the patent implements a prioritization mechanism where HARQ-ACK information is transmitted first (as it has higher priority for maintaining link reliability), and CSI bits are discarded or selectively transmitted. This ensures critical HARQ feedback is preserved while minimizing CSI loss.

Inventive Principle:

Principle #34Discarding and recovering

3Reliability

If PUCCH format 1b with channel selection is used for HARQ-ACK transmission, then HARQ-ACK can be transmitted reliably, but CSI must be dropped when resources overlap

Engineering Contradiction:

ImproveHARQ-ACK transmission reliabilityVSAvoidCSI information loss

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

Instead of using PUCCH format 1b for HARQ-ACK and dropping CSI, the patent inverts the approach by using PUCCH format 2 for both information types through joint multiplexing. This reversal of the traditional separate transmission approach allows CSI to be preserved while maintaining HARQ-ACK reliability through the combined transmission scheme.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10492185B2Multiplexing of channel state information and hybrid automatic repeat request-acknowledgement information

Publication Date: 2019.11.26 APPLE INC

AI summary

Embodiments of the present disclosure describe devices, methods, computer-readable media and systems configurations for multiplexing channel state information and hybrid automatic repeat request-acknowledgement information. Other embodiments may be described and claimed.