FDD-TDD Carrier Aggregation for Asymmetric Traffic
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Solution Overview
Problem
Current wireless communication systems lack the ability to combine Frequency Division Duplex (FDD) and Time Division Duplex (TDD) carriers for Carrier Aggregation (CA), limiting data rate and coverage, especially in environments with insufficient bandwidth and asymmetric traffic requirements.
Innovation Solution
Implementing a method for operating a wireless communication system that aggregates FDD and TDD carriers by using a first carrier with an FDD scheme for uplink communication and a second carrier with a TDD scheme for downlink communication, allowing for expanded TDD coverage and improved data rates through efficient resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If only TDD carriers are used for Carrier Aggregation, then spectrum utilization efficiency is improved, but uplink coverage is insufficient due to TDD uplink limitations
Solution Approach 1:
The patent combines TDD and FDD carriers in a Carrier Aggregation system, where the terminal aggregates a TDD downlink carrier with an FDD uplink carrier. This merging allows the system to benefit from TDD's spectrum efficiency while using FDD's superior uplink coverage capabilities, thereby resolving the contradiction between spectrum utilization and uplink coverage.
2Reliability
If only FDD carriers are used for Carrier Aggregation, then uplink and downlink coverage is sufficient, but spectrum utilization efficiency decreases due to guardband requirements
Solution Approach 1:
The patent merges TDD and FDD carrier types in the Carrier Aggregation system, allowing the terminal to use TDD carriers for downlink where spectrum efficiency is critical and FDD carriers for uplink where coverage is critical. This hybrid approach achieves both high spectrum utilization and sufficient coverage.
3Productivity
If TDD and FDD carriers are combined for Carrier Aggregation, then data rate is improved and coverage is expanded, but system complexity increases due to different duplex schemes
Solution Approach 1:
The patent segments the Carrier Aggregation system into distinct TDD and FDD carrier components, with the terminal independently managing downlink reception on TDD carriers and uplink transmission on FDD carriers. This segmentation allows each carrier type to operate according to its own duplex scheme rules, simplifying the overall system management despite the heterogeneity.
Solution Approach 2:
The terminal in the patent is designed with multi-functionality to support both TDD and FDD carrier aggregation simultaneously. It can receive downlink signals on TDD carriers and transmit uplink signals on FDD carriers, making the terminal universal in handling different duplex schemes and reducing the need for separate systems.
4Productivity
If TDD carriers are used in high frequency environments, then downlink capacity is improved, but uplink coverage is restricted due to path loss
Solution Approach 1:
The patent combines TDD downlink carriers with FDD uplink carriers in the terminal's Carrier Aggregation system. The TDD high-frequency carriers provide high downlink capacity, while the FDD carriers provide robust uplink coverage. This merging allows the terminal to simultaneously achieve high downlink capacity and sufficient uplink coverage despite the frequency and duplex scheme differences.
Data Source
AI summary
An apparatus and a method for a carrier aggregation (CA) operation using a Frequency Division Duplex (FDD) carrier and a Time Division Duplex (TDD) carrier in a wireless communication system are provided. The method includes receiving downlink signals via downlink FDD TDD CA using a first carrier operated in an FDD mode and a second carrier operated in a TDD mode and transmitting, via the first carrier, uplink signals corresponding to the downlink signals received via the first and second carriers.