Fractional Dedicated Physical Channel Power Control During Soft Handover
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Solution Overview
Problem
In digital cellular communications, existing methods for handling over a terminal from a serving cell to a next serving cell using Fractional DPCH (F-DPCH) often result in excessive power usage due to the need to meet quality targets for all radio links, especially in large active sets where some cells are undetectable, leading to unnecessary power increases in detectable cells.
Innovation Solution
A method where the user equipment (UE) applies a quality target only to the F-DPCH radio link from the HS-DSCH serving cell to generate power control commands, ensuring efficient power control and synchronization, while allowing non-serving cells to apply a downlink power offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quality target is applied to all radio links in active set, then reliability of power control is improved, but power consumption increases excessively
Solution Approach 1:
The patent applies the quality target only to the serving cell's F-DPCH radio link rather than all radio links in the active set. This selective application ensures that power control reliability is maintained for the critical serving cell connection while avoiding unnecessary power consumption adjustments for non-serving cells, especially those that are undetectable.
2Measurement precision
If quality criteria are fulfilled for undetectable cells, then measurement precision is improved, but power usage becomes excessive
Solution Approach 1:
The patent extracts the quality target application from the set of all radio links and applies it only to the serving cell's F-DPCH link. This separation eliminates the waste of power that would occur if quality criteria were enforced for undetectable non-serving cells, while still maintaining sufficient measurement precision for the critical serving cell connection.
3Reliability
If power control commands are generated based on all active set cells, then system reliability is improved, but device complexity increases
Solution Approach 1:
The patent simplifies the power control mechanism by applying quality targets selectively only to the serving cell's F-DPCH radio link. This local application reduces the complexity of power control command generation while maintaining system reliability, as the serving cell connection is the critical link that requires precise quality control.
Data Source
Figure 1
Figure 2A~2E
AI summary
A method includes establishing a first radio link with a serving network entity and a second radio link with a target network entity, commencing a soft handover from the serving network entity to the target network entity, receiving a quality target from a network comprising the serving and target network entities, and applying the quality target only to the first radio link to generate a power control command.