Carrier Aggregation PCell Interruption Adaptation
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Solution Overview
Problem
In wireless networks, carrier aggregation operations lead to performance degradation of primary cells due to interruptions caused by wireless devices retuning their receivers for measurements on secondary cells, resulting in missed ACK/NACK packets and difficulty in achieving target block error rates.
Innovation Solution
A method is introduced to determine a target quality and PCell interruption probability for wireless devices, allowing adaptation of CA configuration parameters such as SCell measurement cycles, activation/deactivation of secondary cells, and radio access technology changes to minimize interruptions and maintain target quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireless devices perform measurements on deactivated SCells during carrier aggregation operation, then measurement capability is improved, but PCell transmission reliability deteriorates due to receiver retuning interruptions
Solution Approach 1:
The patent implements dynamic adaptation of SCell measurement cycles based on PCell transmission conditions. The network node determines PCell interruption probability and compares it with target quality metrics, then adjusts measurement cycle parameters dynamically to balance measurement needs against transmission reliability requirements
Solution Approach 2:
The patent changes the parameter of measurement cycle periodicity based on determined PCell interruption probability. When interruption probability exceeds thresholds, the measurement cycle is adjusted to reduce interruptions, thereby changing the temporal parameter of measurement operations to resolve the contradiction between measurement capability and transmission reliability
2Measurement precision
If SCell measurement cycles are shortened to improve measurement accuracy, then measurement precision is improved, but PCell interruption frequency increases causing more missed ACK/NACK packets
Solution Approach 1:
The patent implements a feedback mechanism where the network node determines PCell interruption probability resulting from SCell measurement cycles, compares this probability with target quality metrics, and uses this feedback to adaptively adjust measurement cycle parameters. This closed-loop control ensures measurement accuracy is maintained while keeping interruptions within acceptable limits
Solution Approach 2:
The patent performs preliminary determination of PCell interruption probability before configuring measurement cycles. By predicting the potential harm of measurement interruptions in advance and comparing with target quality, the system prevents excessive missed ACK/NACK packets from occurring in the first place
3Productivity
If carrier aggregation is activated to increase system capacity, then productivity is improved, but PCell performance degradation occurs due to measurement-induced interruptions
Solution Approach 1:
The patent enables dynamic adjustment of CA configuration parameters including SCell measurement cycles and activation/deactivation states based on real-time PCell interruption probability assessment. This dynamic adaptation allows the system to maintain high productivity through CA while preventing PCell performance degradation by adjusting measurement parameters adaptively
Solution Approach 2:
The patent changes CA configuration parameters such as measurement cycle periodicity and SCell activation state based on determined interruption probability and target quality comparisons. These parameter changes allow the system to optimize the balance between system capacity (productivity) and PCell performance (reliability) under different operating conditions
Data Source
AI summary
In certain embodiments, a network node serves a wireless device capable of carrier aggregation involving a primary cell, PCell, and at least one secondary cell, SCell. The network node determines (304) a target quality for the wireless device to achieve with respect to at least the PCell; determines (308) a PCell interruption probability (e.g., probability of missed ACK/NACK in uplink) corresponding to an SCell measurement cycle that can be used by the wireless device for measuring on one or more cells of a secondary component carrier, SCC, with a deactivated SCell; adapts (312) a parameter related to the CA configuration to make it feasible to achieve the target quality, the parameter adapted based on a comparison between the target quality and the PCell interruption probability; and configures (316) the wireless device with the adapted parameter.