Power Headroom Report Triggering in Dual Connectivity
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Solution Overview
Problem
In dual connectivity scenarios for LTE networks, the existing power headroom reporting (PHR) mechanisms face challenges in accurately triggering reports when a user equipment (UE) is connected to multiple eNBs, leading to delays or missed reports due to outdated reference values and complex timing configurations.
Innovation Solution
The solution involves storing separate pathloss reference values for each MAC entity (MeNB and SeNB) in the UE, allowing each entity to use appropriate pathloss differences to trigger PHRs independently, ensuring timely and accurate reporting by aligning with specific thresholds and timers for each cell group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pathloss reference value is used for both MAC entities in dual connectivity, then the system complexity is reduced, but the PHR triggering accuracy deteriorates because the reference value becomes outdated for one of the MACs
Solution Approach 1:
The patent segments the single pathloss reference value into separate pathloss reference values for each MAC entity. Specifically, it maintains a first pathloss reference value for the first MAC entity and a second pathloss reference value for the second MAC entity, allowing each to be independently updated based on respective downlink pathloss measurements. This segmentation resolves the contradiction by enabling accurate PHR triggering for each MAC entity while managing complexity through structured separation.
Solution Approach 2:
The patent applies local quality by making the pathloss reference values specific to each MAC entity's local conditions. Each MAC entity has its own pathloss reference value that reflects the local downlink pathloss measurement, allowing each entity to trigger PHRs based on locally accurate information rather than a generic shared reference.
2Measurement precision
If separate pathloss reference values are stored for each MAC entity, then the PHR triggering accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent manages the increased complexity through systematic segmentation - separating pathloss reference values by MAC entity, organizing them with clear associations to respective cell groups. This structured segmentation makes the complexity manageable and justifiable by the accuracy improvements.
Solution Approach 2:
Each MAC entity independently uses its own pathloss reference value for PHR triggering decisions, making the system self-service in nature. Each entity autonomously determines when to trigger PHR based on its local pathloss conditions without requiring complex coordination, thereby managing complexity through decentralized autonomous operation.
3Loss of time
If PHR triggering events are handled independently for each MAC entity, then the reporting timeliness is improved, but the coordination complexity between eNBs increases
Solution Approach 1:
The patent segments the PHR triggering mechanism into independent evaluations for each MAC entity, with each entity monitoring its own pathloss reference value and triggering PHR independently when conditions are met. This segmentation eliminates coordination delays while managing complexity through clear separation of triggering responsibilities.
Solution Approach 2:
The patent implements preliminary action by having each MAC entity continuously maintain its own pathloss reference value ready for immediate comparison with current measurements. This pre-prepared state enables immediate PHR triggering when pathloss changes exceed thresholds, reducing reporting delays without requiring complex real-time coordination.
Data Source
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AI summary
Various methods are provided fortriggering a power headroom report. One example method may include storing a first pathloss value and a second pathlossvalue for a first entity and a first pathloss value and a second pathloss value for a second entity, for each of the first entity and second entity, determining whether first pathloss value or second pathloss value has changed more than a corresponding threshold value, determining whether the UE has UL resources for a new transmission, and in an instance where, for at least one of the first entity or second entity, the first pathloss value or second pathloss value has changed (e.g., increased or decreased) more than the corresponding threshold value, triggering a PHR.A corresponding apparatus and computer program product are also provided.