UE Scheduling Request Mechanism for Inter-Base Station Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems with inter-base station carrier aggregation, the exchange of information among base stations is limited by backhaul delay and overhead, making it challenging for user equipment (UE) to efficiently communicate and manage multiple schedulers from different base stations, particularly in scenarios requiring dynamic uplink scheduling.
Innovation Solution
The UE monitors SR triggering events, selects base stations based on predefined criteria and algorithms, and performs logical channel prioritization to send scheduling requests (SRs) to multiple schedulers, including options for bearer-binding and soft-bearer-binding configurations, with the ability to re-associate or report failures to the RRC layer for alternative configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE communicates with multiple schedulers from different base stations, then the flexibility and efficiency of uplink scheduling is improved, but the backhaul delay and overhead increase
Solution Approach 1:
The patent segments the scheduling function by allowing the UE to independently communicate with multiple schedulers from different base stations. Each scheduler operates semi-autonomously, making local scheduling decisions without requiring constant coordination through the backhaul, thus reducing backhaul delay while maintaining scheduling flexibility.
Solution Approach 2:
The UE is pre-configured with multiple scheduling requests (SR) and buffer status reports (BSR) for different base stations. This preliminary preparation allows the UE to immediately transmit scheduling information to the appropriate base station when uplink data arrives, eliminating the need for real-time backhaul coordination and reducing scheduling delay.
2Productivity
If the UE associates with multiple schedulers from different base stations, then the system capacity and data rate are improved, but the device complexity increases
Solution Approach 1:
The patent implements local quality by allowing each base station to have its own dedicated scheduling resources and parameters configured specifically for that base station. The UE maintains separate scheduling request configurations for each base station, enabling optimized local scheduling decisions without requiring complex global coordination, thus improving system throughput while managing device complexity.
3Speed
If dedicated SR resources are allocated for each base station, then the scheduling response time is improved, but the overhead and resource consumption increase
Solution Approach 1:
The patent applies partial action by allocating dedicated SR resources only for the primary base station while using contention-based or shared resources for secondary base stations. This approach provides fast scheduling response for the most critical uplink transmissions to the primary base station while reducing overall control channel resource consumption by using lighter-weight mechanisms for less critical transmissions to secondary base stations.
Data Source
AI summary
Apparatus and method are provided to enhance scheduling request to multiple schedulers with inter base station carrier aggregation. In one novel aspect, the UE monitors and detects one or more SR triggering event. The UE selects one or more base stations based on predefined criteria and sends the SR to the selected one or more base stations. In one embodiment, at least one LC of the UE is associated with multiple BSs with association priorities. In one embodiment, the association priorities are configured by the network. In other embodiments, the association priorities are derived based on predefined UE configurations, or are derived from load information received by the UE, or are derived from radio measurements. In one novel aspect, the UE upon detecting SR failure triggered on a triggering LC, sends SR failure indication to a RRC layer or associates the triggering LC with a different base station.