ACK/NACK Resource Mapping for Carrier Aggregation
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Solution Overview
Problem
In LTE wireless communication systems, there is a challenge in efficiently transmitting ACK/NACK signals across multiple cells due to the complexity of scheduling and resource allocation, particularly in carrier-aggregated environments where multiple component carriers are used, leading to difficulties in coordinating uplink and downlink transmissions.
Innovation Solution
The method involves a user equipment (UE) receiving downlink data from multiple cells within a sub-frame and transmitting corresponding uplink data in a subsequent sub-frame, using unique identifiers for each cell to manage ACK/NACK signals, thereby optimizing resource allocation and reducing transmission errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple component carriers are used for carrier aggregation, then data transmission capacity is improved, but scheduling and resource allocation complexity increases
Solution Approach 1:
The patent segments the ACK/NACK feedback by assigning different PUCCH resources (different orthogonal codes, cyclic shifts, or resource blocks) to different component carriers. This allows independent handling of feedback for each carrier, simplifying the scheduling and resource allocation management while maintaining multi-carrier transmission capacity.
Solution Approach 2:
The patent introduces cell-specific identifiers (physical cell IDs) as intermediaries to map downlink component carriers to uplink PUCCH resources. This intermediary mapping mechanism simplifies the coordination between multiple downlink carriers and uplink feedback resources, reducing scheduling complexity.
2Reliability
If ACK/NACK signals are transmitted for multiple cells, then data transmission reliability is improved, but uplink control signaling complexity increases
Solution Approach 1:
The patent merges multiple ACK/NACK signals for different component carriers into a single uplink subframe transmission. By combining the feedback for multiple carriers into one coordinated transmission using cell-specific resource mapping, the system maintains high reliability while reducing the complexity of separate transmissions.
Solution Approach 2:
The patent creates a universal PUCCH resource allocation mechanism that can handle ACK/NACK feedback for any number of component carriers using a standardized mapping approach based on cell identifiers. This multi-functional framework simplifies the control signaling by providing a consistent method regardless of the number of carriers involved.
3Measurement precision
If cell-specific PUCCH resources are allocated, then ACK/NACK signal accuracy is improved, but resource allocation overhead increases
Solution Approach 1:
The patent uses cell-specific parameters (physical cell identifiers) to dynamically determine PUCCH resource allocation without requiring separate dedicated resources for each cell. This parameter-based mapping approach maintains high signal accuracy for distinguishing different cell feedback while minimizing the overhead of resource allocation signaling.
Data Source
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AI summary
Disclosed are a method and an apparatus for transmitting and receiving data. A method for transmitting an uplink comprises the steps of: a terminal receiving first downlink data from a first cell through a first subframe; the terminal receiving second downlink data from a second cell through the first subframe; the terminal transmitting first uplink data, which is generated based on a first identifier of the first cell, as a reply to the first downlink data through a second subframe, and the terminal transmitting second uplink data, which is generated based on a second identifier of a second cell, as a reply to the second downlink data through the second subframe.