LTE-Uplink Resource Retention for Inter-eNB Carrier Aggregation
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Solution Overview
Problem
In LTE-Advanced systems with inter-site or inter-eNB carrier aggregation, the random access procedure for reassigning uplink dedicated resources causes transmission and reception delays, especially when scheduling requests, CQI, and SRS are not assigned, leading to suboptimal link adaptation due to unknown communication quality.
Innovation Solution
User equipment and base stations are equipped with units to determine the cell type providing uplink dedicated resources and manage resources accordingly, allowing retention or reassignment of these resources without executing a random access procedure, thereby avoiding unnecessary reconfiguration and maintaining communication quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the random access procedure is executed for reassigning uplink dedicated resources, then the resources can be reassigned, but transmission and reception delays occur
Solution Approach 1:
The base station performs preliminary actions by maintaining the association between the user equipment and the uplink dedicated resources in the second cell even after resource release. When the user equipment needs to access the small cell again, the base station can quickly reassign the same resources without going through the complete random access procedure, thus reducing transmission delays while ensuring reliable resource assignment.
2Ease of operation
If uplink dedicated resources are released upon occurrence of release trigger, then resource management is simplified, but reassignment requires random access procedure causing delays
Solution Approach 1:
The patent extracts the resource release and reassignment process from the complete random access procedure. The base station releases the uplink dedicated resources from active use but maintains the association information separately. This allows the system to benefit from resource release (simplified management) while preserving the ability to quickly reassign resources when needed (reduced delay) by not requiring a full random access procedure.
3Adaptability or versatility
If multiple base stations transmit and receive RRC signaling, then communication flexibility is improved, but network complexity increases due to required bearers
Solution Approach 1:
The patent segments the control plane and user plane functions between the base stations. The first base station (macro eNB) handles RRC signaling and control plane functions, while the second base station (small eNB) handles uplink dedicated resources and user plane data transmission. This segmentation allows multiple base stations to be involved in communication (improved flexibility) without requiring each base station to establish complete RRC bearers (reduced complexity).
Data Source
AI summary
Some techniques for promptly assigning uplink dedicated resources in inter-site or inter-eNB carrier aggregation are disclosed. One aspect of the present invention relates to a user equipment including a transmission and reception unit configured to use radio resources to communicate with multiple base stations, a resource management unit configured to manage the radio resources and a cell type determination unit configured to determine a type of a cell providing the radio resources, wherein when the resource management unit detects occurrence of a release trigger for assigned uplink dedicated resources, the cell type determination unit determines a type of a cell providing the uplink dedicated resources and retains or releases the uplink dedicated resources depending on the determined cell type.