User Terminal Capability Reporting for FDD-TDD Carrier Aggregation
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Solution Overview
Problem
User terminals face challenges in simultaneous transmission and reception due to interference between uplink and downlink signals when carrier aggregation is employed using different duplex modes, leading to decreased received quality and throughput.
Innovation Solution
A user terminal with a transmitting/receiving section and a report control section that controls the reporting of capability information for simultaneous transmission and reception across various frequency bands, allowing accurate scheduling and preventing inadequate limitations in duplex mode combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is employed using different duplex modes (FDD and TDD) to achieve wider bandwidth and higher data rates, then system capacity and throughput are improved, but uplink transmission interferes with downlink reception causing decreased received quality
Solution Approach 1:
The patent segments the capability information reporting by separating it into per-frequency band basis reports. The user terminal determines capability information for each frequency band combination independently, allowing the system to handle different duplex mode combinations (FDD-FDD, TDD-TDD, FDD-TDD) with their specific interference characteristics separately, rather than applying a blanket limitation across all bands.
Solution Approach 2:
The patent applies local quality by making the capability information specific to each frequency band combination. Instead of a uniform capability report, the terminal provides differentiated capability information for each band combination, allowing the base station to make targeted scheduling decisions for each frequency band pair, optimizing performance for local interference conditions.
2Object-affected harmful factors
If a duplexer is mounted to enable simultaneous uplink transmission and downlink reception in FDD full-duplex mode, then received quality is improved, but device complexity and cost increase
Solution Approach 1:
The patent enables the system to self-adjust by having the user terminal autonomously determine and report its capability information for each frequency band combination. The terminal itself identifies whether it can handle simultaneous transmission and reception for specific band combinations, eliminating the need for the base station to know the terminal's hardware configuration in advance.
Solution Approach 2:
The patent changes the parameter of capability information from a static, uniform value to a dynamic, band-specific value. The capability information varies depending on the frequency band combination, allowing the system to adapt to different hardware configurations and interference scenarios without requiring physical hardware changes.
3Device complexity
If half-duplex FDD is applied to user terminals unable to perform simultaneous transmission and reception, then device complexity is reduced, but throughput and system capacity decrease
Solution Approach 1:
The patent introduces dynamics by making the duplex mode flexible and adaptive rather than fixed. The system can dynamically select between half-duplex and full-duplex operation for each frequency band combination based on the user terminal's reported capability information, allowing terminals to operate in full-duplex mode when capable and half-duplex when necessary.
Solution Approach 2:
The patent applies preliminary action by having the user terminal pre-determine and report its capability information for each frequency band combination before actual data transmission begins. This allows the base station to plan and optimize resource allocation in advance, knowing which terminals can handle simultaneous transmission and reception for specific band combinations.
4Measurement precision
If capability information is reported on a per-frequency band basis to enable accurate scheduling, then scheduling precision is improved, but signaling overhead and processing complexity increase
Solution Approach 1:
The patent applies universality by designing a capability information reporting mechanism that works across all frequency band combinations and duplex mode scenarios (FDD-FDD, TDD-TDD, FDD-TDD). The same reporting framework handles diverse scenarios uniformly, reducing the need for separate mechanisms for each case.
Data Source
AI summary
A user terminal is disclosed that includes a transmitting/receiving section that receives DL signals transmitted from each of an FDD cell and a TDD cell and transmits UL signals to each of the FDD cell and the TDD cell. The user terminal further includes a control section that controls carrier aggregation using the FDD cell and the TDD cell, and controls reporting of capability information regarding simultaneous transmission and reception of the DL signals and UL signals in the transmitting/receiving section, where the control section controls reporting of the capability information regarding simultaneous transmission and reception of the transmitting/receiving section with respect to every combination of a frequency band to use in the FDD cell and a frequency band to use in the TDD cell.