FDD TDD Carrier Aggregation Interference Management
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Solution Overview
Problem
Existing carrier aggregation techniques fail to implement simultaneous operation of Frequency Division Duplex (FDD) and Time Division Duplex (TDD) systems due to interference issues, preventing efficient use of limited radio spectrum for increased bandwidth and data throughput.
Innovation Solution
Control transmission and reception parameters, such as resource block allocation, power limitations, and timing adjustments, to increase frequency separation between FDD and TDD systems, allowing carrier aggregation by reducing interference and optimizing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented between FDD and TDD systems, then bandwidth and data throughput are increased, but interference between the two systems disrupts simultaneous operation
Solution Approach 1:
The patent changes transmission parameters including power spectral density, resource block allocation, and timing advance values for FDD and TDD carriers. By adjusting these parameters, the system optimizes signal transmission while minimizing interference between FDD uplink and TDD downlink, enabling successful carrier aggregation and increased throughput
Solution Approach 2:
The system dynamically adjusts transmission parameters based on channel conditions and interference levels. The base station modifies power spectral density, resource block assignments, and timing advance values in real-time to maintain optimal performance while managing interference between FDD and TDD systems during carrier aggregation operation
2Adaptability or versatility
If frequency allocation for TDD is placed between FDD uplink and FDD downlink, then spectrum utilization is improved, but adjacent-channel interference prevents simultaneous FDD and TDD operation
Solution Approach 1:
The patent applies different transmission characteristics to different parts of the spectrum. Specifically, it adjusts power spectral density and resource block allocation locally for FDD and TDD carriers operating in adjacent frequency bands, allowing the TDD system to operate between FDD uplink and downlink while minimizing adjacent-channel interference through localized parameter optimization
Solution Approach 2:
The system uses timing advance adjustments and power spectral density control as intermediary mechanisms to manage the interaction between FDD and TDD systems. These intermediaries enable the TDD carrier to operate in the frequency gap between FDD uplink and downlink without causing disruptive adjacent-channel interference
Data Source
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Figure 3A~3B
Figure 4A~4B
AI summary
Carrier aggregation may be effected for a mobile terminal (50) in a cellular network environment between a carrier of a Frequency Division Duplex (FDD) system and a carrier of a Time Division Duplex (TDD) system. A receiver for one type of carrier will be susceptible to interference from a transmitter for the other type of carrier, but a parameter of the receiver of the one system and/or the transmitter of the other system may be set such that a non-zero throughput is achieved by communication of both the FDD and the TDD carriers. Base Station (10): Controller (15); FDD uplink receiver (21); FDD downlink transmitter (22); TDD uplink receiver (31); TDD downlink transmitter (32). Mobile Terminal (User Equipment) (50): Controller (55); FDD transmitter (61); FDD receiver (62); TDD transmitter (71); TDD receiver (72). FDD uplink signal (101); FDD downlink signal (102); TDD uplink signal (111); TDD downlink signal (112). Base station interference (122, 132); mobile terminal interference (121, 131).