PDCCH Structure for Carrier Aggregation Control
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Solution Overview
Problem
Current downlink control channel designs in LTE-Advanced systems with Carrier Aggregation technologies face challenges in efficiently transmitting resource allocation information, particularly in achieving backward compatibility and optimal resource utilization.
Innovation Solution
The proposed solution involves dynamically configuring and switching between intra-carrier and inter-carrier PDCCH structures based on user equipment feedback, using higher layer signaling to notify the appropriate PDCCH structure for blind decoding, allowing for flexible resource allocation and improved system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate PDCCH is provided on each carrier frequency, then backward compatibility with LTE system is maintained and control information can be decoded independently, but the device complexity and resource utilization efficiency deteriorate due to multiple independent control channels
Solution Approach 1:
The patent merges control information from multiple carrier frequencies into a single common PDCCH. The PDCCH on one carrier frequency transmits control information for PDSCH on multiple carrier frequencies simultaneously, reducing the number of independent control channels while maintaining comprehensive control coverage across aggregated carriers.
Solution Approach 2:
The common PDCCH is designed with multi-functionality to serve multiple carrier frequencies. A single PDCCH structure can allocate resources and convey control information for multiple component carriers, making the control channel universal across the aggregated bandwidth rather than dedicated to individual carriers.
2Productivity
If control information is jointly encoded on a common PDCCH, then resource utilization efficiency improves and device complexity reduces, but backward compatibility deteriorates and the number of blind decoding operations increases
Solution Approach 1:
The control information in the common PDCCH is segmented into multiple DCI formats, where each format corresponds to a specific carrier frequency or resource allocation pattern. This segmentation allows the receiver to efficiently search through different formats with reduced blind decoding attempts compared to exhaustive joint encoding, while still achieving consolidated control signaling.
Solution Approach 2:
The patent employs parameter changes in DCI formats to indicate different carrier frequency allocations and resource configurations. By varying parameters such as carrier indicator fields, resource block assignments, and modulation schemes within the common PDCCH, the system maintains flexibility and compatibility while achieving efficient multi-carrier control.
3Area of stationary object
If PDCCH spans across all system carrier frequencies, then bandwidth availability for control channels improves, but device complexity increases due to new DCI formats and increased blind decoding requirements
Solution Approach 1:
The common PDCCH employs local quality differentiation by allocating different DCI formats and control information densities to different carrier frequencies based on their specific requirements. Each carrier frequency receives appropriately tailored control information within the unified PDCCH structure, optimizing resource usage without requiring uniform complex formatting across all carriers.
Data Source
AI summary
A mobile communication system where a base station and a user equipment communicates on multiple aggregated carriers is disclosed. In the mobile communication system, the base station notifies to the user equipment information which is relevant to inclusion of an information field indicating scheduling carrier in downlink control information format by using radio resource control signaling, and the user equipment receives, from the base station, downlink control information in the downlink control information format according to the information which is relevant to inclusion of the information field indicating scheduling carrier.