Uplink Control Information Transmission in TDD Multi-Cell Systems
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in transmitting uplink control information across multiple cells, particularly in Time Division Duplex (TDD) systems, where managing resources and accurately acknowledging Physical Downlink Control Channel (PDCCH) signals is challenging, leading to potential errors in ACK/NACK generation.
Innovation Solution
A method and apparatus that receive PDCCH and PDSCH signals across multiple cells, generate per-cell acknowledgement information, and transmit it on a single uplink subframe, concatenating the information sequentially by cell index, with acknowledgment for PDSCH signals without corresponding PDCCH placed at the end, using Downlink Assignment Index (DAI) for PUSCH scheduling or total downlink subframes for PUCCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If per-cell acknowledgement information is transmitted for each cell separately, then the accuracy of ACK/NACK generation is improved, but the complexity of resource management increases
Solution Approach 1:
The patent segments the acknowledgement information transmission by dividing it into per-cell ACK/NACK bits. Each cell's acknowledgement information is generated and transmitted separately, allowing accurate tracking of which PDCCH signals were received on which specific cells. This segmentation resolves the contradiction by maintaining high accuracy through cell-specific acknowledgement generation while managing complexity through systematic concatenation rules.
Solution Approach 2:
The patent introduces a new dimension for organizing acknowledgement information by concatenating per-cell ACK/NACK bits in sequential order of cell index. This dimensional organization transforms the resource management problem from a complex multi-dimensional coordination task into a structured linear sequence, reducing management complexity while preserving accuracy.
2Reliability
If PDSCH signals without corresponding PDCCH are acknowledged, then the reliability of downlink transmission is improved, but the complexity of controlling ACK/NACK transmission increases
Solution Approach 1:
The patent applies preliminary action by placing acknowledgements for PDSCH signals without corresponding PDCCH at predetermined positions (end positions) in the concatenated ACK/NACK sequence. This advance positioning rule simplifies the control mechanism by eliminating the need for dynamic determination of acknowledgement positions, reducing transmission control complexity while ensuring reliable acknowledgment of all downlink transmissions.
3Productivity
If multiple per-cell acknowledgement information are concatenated sequentially, then the efficiency of uplink control information transmission is improved, but the length of the control information increases
Solution Approach 1:
The patent merges multiple per-cell acknowledgement information into a single concatenated uplink control message transmitted on one uplink subframe. By combining all cell-specific ACK/NACK bits in sequential order and transmitting them together, the system improves transmission efficiency through consolidated uplink transmission while managing the increased length through systematic organization and compression techniques.
Data Source
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AI summary
The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and apparatus for transmitting uplink control information when TDD and a plurality of cells are configured, and comprises the following steps: receiving one or more of at least one PDCCH signal and at least one PDSCH signal; generating for each of the cells reception reply information on one or more of the at least one PDCCH signal and the at least one PDSCH signal; and transmitting the reception reply information for each of the plurality of cells which are connected.