Carrier Aggregation for Hybrid FDD TDD Networks
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Solution Overview
Problem
Current wireless communication systems cannot effectively combine Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) systems for carrier aggregation, limiting flexibility and efficiency in hybrid duplexing networks.
Innovation Solution
The implementation of systems and methods that allow for the concurrent use of FDD and TDD cells in carrier aggregation by determining UCI transmission cells, selecting cells for aggregation, and establishing downlink subframe associations, enabling seamless PDSCH and PUSCH scheduling and HARQ-ACK reporting across different duplexing types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If FDD and TDD systems are used separately, then system stability is maintained, but communication flexibility and efficiency are limited
Solution Approach 1:
The patent combines FDD and TDD systems into a unified carrier aggregation framework, allowing simultaneous operation of both duplexing types. The base station aggregates multiple component carriers from different duplexing types (FDD and TDD) to form a hybrid carrier aggregation system, enabling flexible resource allocation while maintaining separate operational characteristics of each duplexing type.
Solution Approach 2:
The patent creates a universal carrier aggregation mechanism that can handle both FDD and TDD component carriers through a common control plane. The system provides multi-functional capabilities by supporting independent scheduling, resource allocation, and HARQ management for different duplexing types within a single unified framework, enhancing adaptability without proportionally increasing complexity.
2Productivity
If separate scheduling is used for FDD and TDD cells, then system stability is maintained, but communication efficiency is reduced
Solution Approach 1:
The patent segments the scheduling mechanism into cell-specific scheduling entities, where each component carrier (FDD or TDD) has its own scheduling module that operates independently according to its duplexing characteristics. This segmentation allows optimized scheduling for each cell type while maintaining overall system coordination through a central controller, improving efficiency without requiring complete reconfiguration of the entire scheduling system.
Solution Approach 2:
The patent implements dynamic scheduling that adapts to the specific requirements of FDD and TDD cells based on real-time channel conditions, traffic demands, and resource availability. The scheduling mechanism dynamically adjusts resource allocation, modulation schemes, and coding rates for each component carrier, enabling high-speed data transmission while maintaining stability through adaptive control rather than rigid fixed patterns.
3Measurement precision
If unified HARQ reporting is used for all cells, then system complexity is reduced, but reporting accuracy is compromised
Solution Approach 1:
The patent introduces an intermediary HARQ management layer that sits between the physical HARQ processes and the higher-layer control functions. This intermediary layer standardizes HARQ reporting formats and timing relationships for both FDD and TDD cells, translating cell-specific HARQ requirements into a unified reporting structure. This approach maintains reporting accuracy by preserving cell-specific HARQ characteristics while reducing overall complexity through standardized interfaces and common processing logic.
Data Source
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AI summary
A User Equipment (UE) for performing carrier aggregation is described. The UE includes a processor and instructions stored in memory that is in electronic communication with the processor. The UE determines an uplink control information (UCI) transmission cell in a wireless communication network with at least one frequency-division duplexing (FDD) cell and at least one time-division duplexing (TDD) cell. The UE also selects a first cell for FDD and TDD carrier aggregation. The UE further determines a set of downlink subframe associations for the first cell that indicate at least one UCI transmission uplink subframe of the UCI transmission cell. The UE additionally sends Physical Downlink Shared Channel (PDSCH) Hybrid Automatic Repeat Request Acknowledgement/Negative Acknowledgement (HARQ-ACK) information in the UCI transmission uplink subframe of the UCI transmission cell.