FDD-TDD Carrier Aggregation Link Quality Prediction
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Solution Overview
Problem
LTE systems face challenges in managing frequency-division-duplex and time-division-duplex carrier aggregation, particularly in allocating traffic across multiple frequency bands to maximize throughput and coverage, while ensuring reliable uplink and downlink performance, especially in scenarios with limited FDD spectrum and high propagation losses.
Innovation Solution
A method to predict link quality and determine the primary cell for user equipment, deciding between time-division-duplex and frequency-division-duplex carriers based on uplink capacity and reliability, using measurements like signal-to-interference-plus-noise-ratio and pathloss differences, to optimize carrier aggregation and allocate traffic effectively across FDD and TDD carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FDD carrier aggregation is used to ensure reliable uplink performance, then uplink reliability is improved, but downlink throughput is limited by available FDD spectrum
Solution Approach 1:
The patent combines FDD and TDD carriers into a unified carrier aggregation system. The FDD carrier provides reliable uplink coverage while the TDD carrier contributes additional downlink capacity, merging the strengths of both duplex modes to simultaneously improve uplink reliability and downlink throughput.
Solution Approach 2:
The system creates a multi-functional carrier aggregation framework that can adaptively serve different traffic types. The FDD carrier handles uplink-critical traffic while the TDD carrier handles downlink-critical traffic, making the aggregated system universally capable of handling diverse service requirements.
2Productivity
If TDD carrier aggregation is used to increase downlink capacity, then downlink throughput is improved, but uplink performance deteriorates due to limited TDD uplink resources
Solution Approach 1:
The patent merges TDD and FDD carriers in aggregation, where the TDD carrier provides enhanced downlink capacity and the FDD carrier supplements uplink performance. This combination allows the system to achieve high downlink capacity while maintaining reliable uplink through the FDD component.
3Ease of operation
If carrier aggregation management is simplified to ease operation, then ease of operation is improved, but network performance optimization is reduced
Solution Approach 1:
The system implements self-service through automated link quality prediction and adaptive carrier selection. The network automatically predicts link quality for FDD and TDD carriers, determines the optimal primary cell, and configures carrier aggregation without manual intervention, achieving both ease of operation and performance optimization.
Solution Approach 2:
The patent incorporates feedback mechanisms where link quality predictions continuously inform carrier aggregation configuration decisions. The system monitors link quality metrics and dynamically adjusts primary cell selection and carrier aggregation settings based on predicted performance, creating a closed-loop optimization system.
Data Source
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AI summary
A method and apparatus may predict a link quality. The method may also include determining a primary cell for a user equipment based on the predicted link quality. The determining the primary cell comprises determining whether the user equipment should be served by a time-division-duplex carrier or by a frequency-division-duplex carrier. The method may also include determining a carrier aggregation to be used by the user equipment based on the predicted link quality.