Dynamic Carrier Reconfiguration for Uplink Intermodulation Distortion
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Solution Overview
Problem
Carrier-aggregation in cellular networks can lead to interference on the uplink channel of the primary cell (PCell) due to intermodulation distortion from concurrent downlink transmissions, affecting voice-over-packet call quality.
Innovation Solution
An access node determines high intermodulation distortion on the uplink channel of the PCell and swaps it with a secondary cell (SCell) to improve voice communication quality by reconfiguring the carrier aggregation, ensuring the new PCell has minimal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is used to increase data rate, then productivity is improved, but intermodulation distortion occurs on the uplink channel causing voice call quality degradation
Solution Approach 1:
The patent implements dynamic carrier reconfiguration where the access node monitors intermodulation distortion levels on the PCell uplink channel and swaps the PCell with an SCell when distortion exceeds a threshold. This dynamic adaptation allows the system to maintain carrier aggregation benefits while avoiding interference conditions that degrade voice call quality.
Solution Approach 2:
The system changes the operating parameters by swapping component carriers based on calculated intermodulation distortion levels. When the PCell experiences high distortion from concurrent downlink transmissions, the access node reconfigures the uplink carrier to an alternative SCell, thereby changing the frequency parameters to avoid the harmful intermodulation products.
2Productivity
If concurrent downlink transmissions are performed to increase throughput, then productivity is improved, but intermodulation distortion on the uplink channel increases
Solution Approach 1:
The access node continuously monitors the uplink channel quality and calculates intermodulation distortion levels resulting from concurrent downlink transmissions. When distortion exceeds a predetermined threshold, the system provides feedback by triggering a carrier swap, thereby adjusting the configuration to eliminate the harmful effect while maintaining overall throughput.
3Device complexity
If PCell is used for both downlink and uplink to simplify configuration, then device complexity is reduced, but voice call quality deteriorates due to interference
Solution Approach 1:
The patent segments the carrier roles by separating the downlink PCell from the uplink SCell when intermodulation distortion is detected. This segmentation allows the system to maintain the simplified PCell configuration for downlink while assigning a different SCell for uplink transmissions, thereby isolating the voice call from interference while preserving configuration simplicity through automated management.
Data Source
AI summary
When an access node is providing a UE with carrier-aggregation service on a PCell in combination with one or more SCells and the UE engages in a voice call including uplink voice communication on the PCell, the access node will determine that there is a threshold high level of IMD on the uplink resulting from concurrent downlink transmissions, and the access node will responsively swap the UE's PCell with one of the UE's one or more SCells. In a representative implementation, the decision to swap these carriers in the UE's connection could be based on a further determination that the level of IMD on the uplink of the SCell is not threshold high.