Carrier Aggregation Duplex Scheme Management
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Solution Overview
Problem
In LTE systems, carrier aggregation with different duplex schemes applied to fundamental frequency blocks poses challenges in managing duplex schemes effectively, leading to issues with transmission delay and coverage, especially when FDD and TDD schemes are applied uniformly across all frequency blocks.
Innovation Solution
A radio communication system that configures its frequency band by adding or deleting fundamental frequency blocks, allowing for FDD-based communication on one block and TDD-based or half-duplex FDD-based communication on another, enabling efficient duplex scheme control between radio base stations and mobile terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same duplex scheme (FDD or TDD) is applied uniformly to all fundamental frequency blocks, then system simplicity is maintained, but transmission delay increases and spectral efficiency is reduced
Solution Approach 1:
The system divides the frequency band into multiple fundamental frequency blocks (component carriers), allowing each block to be independently configured with appropriate duplex schemes. This segmentation enables different parts of the frequency spectrum to operate under optimal duplex modes (FDD, TDD, or half-duplex FDD) based on traffic requirements, thereby reducing transmission delay without overwhelming system complexity
Solution Approach 2:
The duplex scheme configuration is made dynamic and flexible, allowing the system to adaptively select and switch between different duplex schemes (FDD, TDD, half-duplex FDD) for different fundamental frequency blocks based on real-time traffic conditions. This dynamic approach optimizes spectral efficiency and reduces transmission delay by matching the duplex mode to the actual communication needs
2Speed
If FDD scheme is applied to all frequency blocks, then uplink and downlink communication can be performed simultaneously, but spectral efficiency is reduced when uplink traffic is light
Solution Approach 1:
The system dynamically changes the duplex scheme parameter for different fundamental frequency blocks based on traffic conditions. When uplink traffic is light, the system can switch from FDD to TDD or half-duplex FDD mode for those blocks, thereby improving spectral efficiency by using the frequency resources more effectively without compromising overall communication speed
3Productivity
If TDD scheme is applied to all frequency blocks, then spectral efficiency is improved, but transmission delay increases due to time-separated uplink and downlink
Solution Approach 1:
The frequency band is segmented into multiple fundamental frequency blocks, allowing simultaneous application of different duplex schemes across different blocks. This enables the system to combine the spectral efficiency benefits of TDD in blocks where it is appropriate with the simultaneous uplink-downlink capability of FDD in blocks where low latency is critical
4Quantity of substance
If carrier aggregation with multiple fundamental frequency blocks is implemented, then bandwidth is increased and peak data rates are improved, but duplex scheme management becomes more complex
Solution Approach 1:
The aggregated carrier is divided into multiple fundamental frequency blocks that can be independently configured with different duplex schemes. This segmentation approach manages complexity by allowing independent control of each block while maintaining overall carrier aggregation functionality
Solution Approach 2:
The system implements a universal duplex scheme management mechanism that can handle multiple duplex modes (FDD, TDD, half-duplex FDD) within the same carrier aggregation framework. This multi-functional approach simplifies management by providing a unified control structure that accommodates diverse duplex configurations across different frequency blocks
Data Source
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AI summary
Provided are a radio communication system, a radio base station apparatus and a mobile terminal apparatus to which duplex schemes are applied effectively in a communication system of which a frequency band is formed with a plurality of fundamental frequency blocks. In the radio communication system of which a frequency band allocated to radio communication between the radio base station apparatus and the mobile terminal apparatus is configured by adding or deleting fundamental frequency blocks, the fundamental frequency blocks of the frequency band have at least a first fundamental frequency block and a second fundamental frequency block, the first fundamental frequency block is used to perform FDD-based radio communication and the second fundamental frequency block is used to perform TDD-based or half duplex FDD-based radio communication.