LTE-Advanced PUCCH ACK/NAK Transmission via Antenna Mapping
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Solution Overview
Problem
Current LTE-Advanced systems face inefficiencies in transmitting uplink control signals using multiple transmit antennas, as existing schemes do not effectively utilize multiple PUCCH resources, leading to sub-optimal ACK/NAK signaling and limited support for transmitting more than 4 bits per sub-frame.
Innovation Solution
The method involves a one-to-one mapping of PUCCH resources between antennas, bundling or multiplexing control signals across multiple antennas, and optimizing constellation points to maximize Euclidean distance, allowing for simultaneous transmission of multiple ACK/NAK bits over multiple PUCCH resources during a single uplink sub-frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple PUCCH resources are reserved for multiple transmit antennas, then the system can support transmission of more ACK/NAK bits, but the PAPR (Peak-to-Average Power Ratio) increases significantly
Solution Approach 1:
The patent segments the multiple ACK/NAK bits into different groups, where some bits are transmitted via PUCCH Format 1a/1b on multiple antennas and other bits are transmitted via PUCCH Format 2/2a/2b. This segmentation allows the system to transmit more bits without requiring all bits to use the resource-intensive Format 1a/1b on multiple antennas, thereby controlling PAPR while increasing overall bit transmission capacity.
Solution Approach 2:
The patent introduces a new dimension for control signal transmission by utilizing PUCCH Format 2/2a/2b in addition to Format 1a/1b. This adds another transmission dimension (different PUCCH format types) that can carry control bits, allowing the system to expand bit transmission capacity without over-relying on multi-antenna Format 1a/1b transmission that causes high PAPR.
2Quantity of substance
If multiple PUCCH Format 1a/1b resources are used for ACK/NAK transmission, then more bits can be transmitted in parallel, but the device complexity increases
Solution Approach 1:
The patent segments the control bit transmission task across different PUCCH format types. Format 1a/1b handles some bits on multiple antennas while Format 2/2a/2b handles other bits. This segmentation reduces the complexity of managing multiple Format 1a/1b resources by distributing the load to Format 2 resources, which have different resource allocation and detection characteristics.
Solution Approach 2:
The patent makes the PUCCH resource pool multi-functional by allowing both Format 1a/1b and Format 2/2a/2b to carry ACK/NAK bits. This universality means the system can flexibly allocate bits to different format types based on channel conditions and bit requirements, reducing the overall complexity of resource management compared to using only Format 1a/1b for all bits.
3Reliability
If single-carrier transmission is used for UL coverage, then coverage performance is improved, but the ability to transmit multiple ACK/NAK bits efficiently is limited
Solution Approach 1:
The patent introduces another dimension for control signal transmission by utilizing PUCCH Format 2/2a/2b in addition to Format 1a/1b. This adds another transmission dimension (different PUCCH format types) that can carry control bits, allowing the system to expand bit transmission capacity without over-relying on multi-antenna Format 1a/1b transmission that causes high PAPR.
Solution Approach 2:
The patent segments the multiple ACK/NAK bits into different groups, where some bits are transmitted via PUCCH Format 1a/1b on multiple antennas and other bits are transmitted via PUCCH Format 2/2a/2b. This segmentation allows the system to transmit more bits without requiring all bits to use the resource-intensive Format 1a/1b on multiple antennas, thereby controlling PAPR while increasing overall bit transmission capacity.
Data Source
AI summary
A method of transmitting uplink control signals/status bits from a user equipment, said user equipment having multiple transmit antennae, and said control signals correspond to a plurality of previous downlink transmissions, wherein said control signals are transmitted over a plurality of PUCCH resources and over said multiple antennae, and transmitted during a single uplink sub-frame. Use of multiple PUCCH resources and multiple antennae allow greater spatial diversity.