Serving Grant Maintenance During Cell Change in HSUPA
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, particularly in HSUPA, maintaining service continuity and efficient resource allocation during cell changes is challenging due to limitations in packet scheduler functionality and bandwidth constraints, leading to spectral inefficiency and errors in assessing the Serving Grant (SG) value.
Innovation Solution
A method and apparatus for a mobile terminal to store and manage the Serving Grant (SG) value, allowing it to maintain the current SG value during cell changes unless a new value is explicitly provided through higher-layer signaling, ensuring seamless service continuity and efficient resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the packet scheduler is located in the RNC with conservative allocation to accommodate inactive users, then service continuity is maintained, but spectral efficiency deteriorates for high allocated data-rates and long release timer values
Solution Approach 1:
The patent segments the scheduling functionality by introducing a secondary cell-specific scheduler at the Node B level that operates independently from the RNC scheduler. This allows the RNC to maintain conservative scheduling for service continuity while the Node B scheduler provides aggressive, fast scheduling for spectral efficiency in the secondary cell
Solution Approach 2:
The patent introduces an intermediary mechanism where the RNC provides a Serving Grant (SG) value that acts as a reference for the Node B scheduler. The Node B uses this SG value to determine the secondary grant, enabling coordinated scheduling between RNC and Node B that balances reliability and productivity
2Reliability
If the RNC reassesses the SG value during cell change through RRC signaling, then service continuity can be maintained, but measurement precision deteriorates due to difficulty in assessing the value of SG and large errors
Solution Approach 1:
The patent applies preliminary action by having the RNC provide the SG value before the cell change occurs through RRC signaling. This pre-configured SG value serves as a reference that the UE and Node B use during the cell change, eliminating the need for reassessment and avoiding measurement errors
Solution Approach 2:
The patent uses copying by having the UE store and reuse the SG value from the source cell in the target cell. The SG value is copied from the RRC connection reconfiguration message and maintained by the UE, avoiding the need for the RNC to reassess and potentially err in the new cell conditions
3Productivity
If the SG is transferred to Node B scheduler with EDCH, then resource allocation efficiency improves, but device complexity increases due to distributed scheduling functionality
Solution Approach 1:
The patent segments the scheduling functionality into two distinct components: the RNC scheduler that provides the Serving Grant (SG) for service continuity, and the Node B scheduler that provides the secondary grant for resource allocation efficiency. This segmentation allows each component to specialize without excessive complexity
Solution Approach 2:
The patent introduces dynamics by making the scheduling system adaptive through the relationship between SG and secondary grant. The Node B scheduler dynamically adjusts the secondary grant based on the SG value and current channel conditions, enabling efficient resource allocation without static complexity
Data Source
Figure 1
Figure 2~2A
Figure 2B
AI summary
A method includes storing a first Serving Grant (SG) value for use in a first serving cell, entering a second serving cell, receiving an information element from a higher layer, maintaining the first SG value if the information element does not include a second SG value, and changing the first SG value to the second SG value if the information element includes a second SG value.