Carrier Aggregation Control Information Handling
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Solution Overview
Problem
Carrier aggregation-based wireless communication systems face challenges in efficiently transmitting control information and acknowledgement information on downlink/uplink signals due to complexities in subframe configurations and control information formats.
Innovation Solution
The method involves configuring user equipment (UE) with different subframe configurations for primary and secondary cells, using an N-bit field in the uplink downlink control information (DCI) format to determine subframe indices or indicate downlink assignment indices, and transmitting physical uplink shared channel (PUSCH) signals accordingly, based on specific uplink-downlink configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is used to increase bandwidth, then system capacity is improved, but control information transmission complexity increases due to multiple cells with different subframe configurations
Solution Approach 1:
The patent segments the control information transmission process by cell type (first cell vs. second cell) and by subframe configuration (UL-DL configuration #0 vs. others). Different segmentation strategies are applied to different cell configurations, allowing complex control information to be divided into manageable processing units for each cell type.
Solution Approach 2:
The patent dynamically adapts the control information format based on the cell's UL-DL configuration. The N-bit field in DCI format changes its meaning based on whether the cell uses configuration #0 or configurations #1-#6, allowing the system to flexibly adjust control information interpretation without requiring separate dedicated fields for each configuration type.
2Adaptability or versatility
If multiple UL-DL configurations are supported for carrier aggregation, then system flexibility is improved, but control information format complexity increases
Solution Approach 1:
The patent creates a universal control information format where a single N-bit field serves multiple functions depending on the cell's UL-DL configuration. The same field indicates subframe index for configuration #0 cells and downlink assignment index for configurations #1-#6, eliminating the need for separate dedicated fields for each configuration type.
Solution Approach 2:
The patent changes the interpretation parameter of the N-bit field based on the cell's UL-DL configuration. By detecting which configuration is active, the system dynamically changes what the N-bit field represents, allowing one field to adapt to different configuration requirements without changing the physical format.
3Productivity
If subframe configurations are differentiated for primary and secondary cells, then resource allocation efficiency is improved, but processing complexity for control information increases
Solution Approach 1:
The patent applies different control information processing rules to different cell types. Primary cells use one set of rules while secondary cells with UL-DL configuration #0 use another set, and secondary cells with configurations #1-#6 use a third set. This localized differentiation allows optimized resource allocation for each cell type while keeping individual processing rules relatively simple.
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 in which a terminal transmits control information in a CA-based wireless communication system and to an apparatus for the method, the method comprising: Receiving a downlink control information (DCI) format comprising resource allocation information and a downlink assignment index (DAI) field, for the secondary cell; Receiving a physical downlink shared channel (PDSCH) indicated by the DCI format through the secondary cell; and transmitting a set of one or more hybrid automatic repeat request (HARQ)-acknowledgement (ACK) bits (o0,o1,...,oN-1) for the secondary cell, wherein oi (i=0, 1, ..., N-1) is i-th HARQ-ACK bit and N is the number of HARQ-ACK bits, wherein if a carrier indicator field (CIF) is enabled in the DCI format, one or more HARQ-ACK bits for the PDSCH are given as (i) o0 or (ii) o0 and o1, regardless of the value of the DAI field in the DCI format, and wherein subframe configurations according to the UL-DL configurations #0 to #6 are shown in the following table 1: where, D denotes a DL subframe, U denotes a UL subframe, and S denotes a special subframe.