ACK/NACK Transmission via PUCCH Formats in Carrier Aggregation
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in transmitting control information, particularly in carrier aggregation scenarios, where existing methods struggle to effectively allocate resources and efficiently transmit ACK/NACK signals across multiple carriers.
Innovation Solution
The proposed method involves using a sequence generated by a root sequence and cyclic shift for ACK/NACK transmission in one PUCCH format, and discrete Fourier transform (DFT) for another, allowing for efficient resource allocation and signal processing in user equipment (UE) to enhance control information transmission in wireless communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented to support multiple carriers, then system capacity and data rate are improved, but control information transmission complexity and resource allocation difficulty increase
Solution Approach 1:
The patent segments control information into different types (ACK/NACK, CQI, RI) and assigns them to different PUCCH formats and resource regions. ACK/NACK uses format 1a/1b in dedicated regions, while CQI/RI use format 2 in other regions, allowing independent optimization of each control information type without interference.
Solution Approach 2:
The patent introduces frequency domain resource division by allocating different physical resource blocks (PRBs) for different control information types. This adds a frequency dimension to control information multiplexing, enabling simultaneous transmission of multiple control signals without time or code conflicts.
2Productivity
If multiple PUCCH formats are used for different control information types, then control information transmission efficiency is improved, but resource allocation complexity increases
Solution Approach 1:
The patent applies different PUCCH formats to different control information types based on their specific requirements. Format 1a/1b with sequence generation is used for ACK/NACK requiring high reliability, while format 2 with DFT is used for CQI/RI requiring higher data rate, optimizing each control information type locally.
Solution Approach 2:
The patent creates a universal resource allocation framework where multiple PUCCH formats share the same uplink control channel structure but use different resource regions and formats. This allows the system to handle various control information types through a unified mechanism rather than separate dedicated channels.
3Reliability
If sequence generation with root sequence and cyclic shift is used for ACK/NACK, then transmission reliability is improved, but signal processing complexity increases
Solution Approach 1:
The patent uses self-service properties of Zadoff-Chu sequences where the same root sequence with different cyclic shifts automatically provides orthogonal or near-orthogonal signals. The sequences self-generate their orthogonality properties without requiring additional processing, reducing complexity while maintaining reliability.
Solution Approach 2:
The patent changes parameters of the base sequence (cyclic shift values, root indices) to create distinct ACK/NACK channels. By varying these parameters rather than using completely different signal structures, the system achieves multiple reliable channels from a single sequence template, reducing overall complexity.
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AI summary
The present invention relates to a wireless communication system. More particularly, the present invention relates to a method for transmitting acknowledgement/negative ACK (ACK/NACK) in a wireless communication system which supports carrier aggregation, and to an apparatus for the method. A method in which a terminal transmits ACK/NACK in a wireless communication system that supports carrier aggregation comprises the following steps: receiving one or more physical downlink shared channels (PDSCHs); and transmitting ACK/NACK for said one or more PDSCHs via a physical uplink control channel (PUCCH). A PUCCH format for transmitting ACK/NACK is selected by taking the type of the carrier in which said one or more PDSCHs are received into account.