Carrier Aggregation with Downlink-Only TDD Subframes
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Solution Overview
Problem
Conventional carrier aggregation systems in wireless communication are limited to aggregating carriers of the same mode, such as FDD or TDD, and require both uplink and downlink subframes in TDD systems, which may not be suitable for future wireless communication needs.
Innovation Solution
A method and apparatus for aggregating carriers that include configuring a time division duplex (TDD) carrier with uplink and downlink subframes on different times in a frame and a downlink-only carrier, allowing for effective carrier aggregation even with new types of carriers that lack backward compatibility, and providing HARQ-timing support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only carriers of the same mode (FDD or TDD) are aggregated, then system compatibility and stability are maintained, but carrier aggregation flexibility and adaptability to future communication needs are limited
Solution Approach 1:
The patent segments the carrier aggregation function into independent configuration components. Each carrier (first carrier and second carrier) can be independently configured with different modes (FDD or TDD) and subframe structures. This segmentation allows the system to aggregate carriers of different modes while maintaining individual carrier stability and compatibility.
Solution Approach 2:
The patent creates a universal carrier aggregation framework that can handle multiple carrier types (FDD and TDD) within the same system. The base station and user equipment are designed with multi-functional capabilities to support both FDD and TDD carriers, enabling flexible aggregation configurations without requiring separate systems for different carrier modes.
2Adaptability or versatility
If TDD carriers require both uplink and downlink subframes, then bidirectional communication is ensured, but system complexity increases and future communication needs cannot be met
Solution Approach 1:
The patent introduces dynamic carrier configuration where the second carrier can be flexibly set as either a full TDD carrier (with both uplink and downlink subframes) or a downlink-only carrier. This dynamic configurability allows the system to adapt to different communication scenarios and future needs while maintaining manageable complexity through standardized configuration procedures.
Solution Approach 2:
The patent changes the subframe configuration parameters of the second carrier, allowing it to have different subframe structures compared to the first carrier. Specifically, the second carrier can be configured with downlink-only subframes or different uplink-downlink configurations, enabling flexible adaptation to various communication requirements without increasing overall system complexity.
3Adaptability or versatility
If new types of carriers without backward compatibility are introduced, then future communication capabilities are enhanced, but compatibility with existing systems is lost
Solution Approach 1:
The patent introduces a downlink-only carrier as an intermediary between traditional TDD/FDD carriers and future carrier types. This intermediate carrier type provides a transition path that maintains backward compatibility while enabling support for new communication capabilities. The downlink-only carrier can be aggregated with existing carriers without requiring changes to legacy system operations.
Data Source
AI summary
The present invention relates to a method and apparatus for aggregating carriers in wireless communication systems. In the method, a first carrier is set up, and a second carrier is added in addition to the first carrier. In addition, the first carrier is a time division duplex (TDD) carrier for which an uplink subframe and a downlink subframe are positioned at different times in a frame, and the second carrier is a carrier only for a downlink that consists of downlink subframes.