Uplink Control Information Transmission Bit Allocation

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Solution Overview

Problem

In LTE-A CA systems, the concurrent transmission of ACK/NACK and periodic CSI is limited by the maximum number of carrying bits in PUCCH format 3, leading to inaccurate determination of transmission bits for ACK/NACK and CSI, resulting in potential bundling and dropping of CSI.

Innovation Solution

A method where the UE dynamically determines the number of transmission bits for ACK/NACK and CSI based on a threshold number of bits in the current subframe, ensuring that the total number of transmitted bits does not exceed the threshold, by selecting downlink carriers according to CSI reporting type priorities and adjusting the number of feedback bits to avoid exceeding the maximum capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the maximum transmission capacity of PUCCH format 3 is set to 22 bits, then ACK/NACK information of multiple carriers can be transmitted, but the concurrent transmission of ACK/NACK and periodic CSI is not supported, resulting in CSI being dropped

Engineering Contradiction:

Improvetransmission capacity of ACK/NACK bitsVSAvoidCSI information loss

Core Design Contradiction:

Quantity of substanceVSLoss of information

Solution Approach 1:

The patent dynamically adjusts the number of CSI bits to be transmitted based on the available capacity in PUCCH format 3. When ACK/NACK and CSI are both present, the system calculates the remaining bits (22 - ACK/NACK bits) and transmits only that many CSI bits, rather than using a fixed allocation. This dynamic adjustment allows concurrent transmission while preventing overflow.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of CSI transmission bits from a fixed value to a variable value determined by the equation: CSI bits = min(CSI report bits, 22 - ACK/NACK bits). This parameter change enables the system to adapt the CSI transmission capacity based on the actual ACK/NACK load, resolving the contradiction between supporting multiple carriers and maintaining CSI transmission.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If concurrent transmission of ACK/NACK and periodic CSI is supported in PUCCH format 3, then both information types can be transmitted simultaneously, but the determination of transmission bits becomes inaccurate, leading to potential bundling or dropping

Engineering Contradiction:

Improveconcurrent transmission capabilityVSAvoidtransmission bit determination accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary calculation of the available bit capacity before transmitting CSI. The system first determines the number of ACK/NACK bits, then calculates the remaining capacity (22 - ACK/NACK bits), and finally transmits only that many CSI bits. This preliminary action ensures accurate bit determination and prevents overflow or dropping.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the base station configures the maximum capacity (22 bits) and the UE feedbacks the actual number of bits used for ACK/NACK. The base station then determines the exact number of CSI bits to transmit based on this feedback, ensuring precise bit allocation and avoiding determination errors.

Inventive Principle:

Principle #23Feedback

3Quantity of substance

If multiple carriers have CSI feedback requirements in the same subframe, then only one carrier's CSI can be selected for transmission, but this results in loss of CSI information from other carriers

Engineering Contradiction:

Improvenumber of CSI bits transmittedVSAvoidCSI information loss from unselected carriers

Core Design Contradiction:

Quantity of substanceVSLoss of information

Solution Approach 1:

The patent applies partial action by transmitting only the necessary portion of CSI bits that fit within the available capacity. Instead of selecting one carrier and completely dropping others, the system transmits a partial set of CSI bits from multiple carriers proportionally, or selects carriers based on priority while ensuring the total does not exceed the capacity. This partial transmission reduces information loss compared to complete dropping.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP2882127B1Method and device for transmitting uplink control information (UCI)

Publication Date: 2018.01.03 CHINA ACAD OF TELECOMM TECH

Figure 1~2A
Figure 2B~2C
Figure 2D~2E

AI summary

A first type of UCI that needs to be transmitted in a current subframe is generated by a terminal device; a second type of UCI that needs to be transmitted in the current subframe is generated on the basis of a threshold number of bits simultaneously transmitted with the UCI in the current subframe and of the number of bits transmitting the first type of UCI; the first type of UCI and the second type of UCI generated are transmitted on corresponding channel resources in the current subframe.