Uplink Control Information Transmission for LTE-A Carrier Aggregation
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Solution Overview
Problem
In LTE-Advanced (LTE-A) carrier aggregation systems, the increased uplink control information (UCI) overhead due to features like coordinated multipoint transmission (COMP) and higher order MIMO requires new methods to efficiently carry UCI, as the payload size of Release 8 LTE PUCCH may not be sufficient.
Innovation Solution
The method involves transmitting UCI using carrier aggregation, specifically using the uplink control channel, uplink shared channel, or uplink data channel, and includes configuring and multiplexing periodic uplink data channels to handle high volume variable size WTRU feedback. This approach supports flexible configuration, efficient resource utilization, and high volume UCI overhead in LTE-A.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation with multiple component carriers is used to increase transmission bandwidth, then data rates are improved, but uplink control information overhead is increased
Solution Approach 1:
The patent segments UCI transmission across multiple physical channels (PUCCH and PUSCH) and multiple component carriers. Different types of control information are divided and transmitted on appropriate channels, with PUCCH handling periodic feedback and PUSCH handling aperiodic or additional control data, thereby distributing the control overhead burden across multiple transmission paths
Solution Approach 2:
The patent introduces a new dimension for UCI transmission by utilizing both control channel (PUCCH) and data channel (PUSCH) resources simultaneously. This multi-dimensional approach allows control information to be transmitted through multiple channels and carriers, effectively increasing the capacity to handle UCI overhead without limiting data transmission
2Device complexity
If Release 8 LTE PUCCH format is used, then device complexity is maintained, but payload size is insufficient for LTE-A requirements
Solution Approach 1:
The patent merges PUCCH and PUSCH transmission resources to handle UCI. When PUCCH payload capacity is insufficient, control information is combined with uplink data transmissions on PUSCH, allowing the system to leverage existing channel structures while achieving the required payload capacity for LTE-A carrier aggregation
Solution Approach 2:
The patent makes the uplink data channel (PUSCH) serve dual purposes: transmitting user data and carrying uplink control information. This multi-functional approach allows the same physical resource to handle both data and control traffic, effectively increasing payload capacity without adding dedicated control channel complexity
3Productivity
If high order MIMO and COMP are implemented, then system capacity is improved, but channel status report overhead is increased
Solution Approach 1:
The patent segments channel status reports into different components (CQI, PMI, RI) and transmits them through appropriate channels based on their periodicity and urgency. Wideband CQI may be transmitted periodically on PUCCH while more detailed subband CQI or aperiodic reports are handled through PUSCH, distributing the reporting overhead across multiple transmission opportunities and channels
Data Source
AI summary
A method and apparatus for transmitting uplink control information (UCI) for Long Term Evolution-Advanced (LTE-A) using carrier aggregation is disclosed. Methods for UCI transmission in the uplink control channel, uplink shared channel or uplink data channel are disclosed. The methods include transmitting channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), hybrid automatic repeat request (HARQ) acknowledgement/non-acknowledgement (ACK/NACK), channel status reports (CQI/PMI/RI), source routing (SR) and sounding reference signals (SRS). In addition, methods for providing flexible configuration in signaling UCI, efficient resource utilization, and support for high volume UCI overhead in LTE-A are disclosed.