Inter-eNB Carrier Aggregation DRX Coordination
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Solution Overview
Problem
Conventional LTE networks face challenges with discontinuous reception (DRX) operations during inter-eNB carrier aggregation, particularly when serving cells are associated with different enhanced NodeBs, leading to difficulties in determining control channel reception times and managing uplink scheduling, random access, and buffer status reports.
Innovation Solution
Implementing independent DRX operations for multiple serving cells belonging to different eNBs, with coordinated parameter management and bitmaps for active time determination, time-domain multiplexing for uplink scheduling, and direct communication for random access and buffer status reporting across eNBs to synchronize and optimize DRX cycles and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is performed between macro-cells and pico-cells served by different eNBs to achieve offloading and reduce handover frequency, then network efficiency and user equipment efficiency are improved, but the complexity of determining control channel reception times and managing DRX operations increases
Solution Approach 1:
The patent segments the DRX operation management by introducing separate DRX parameter sets for different eNBs in an inter-eNB carrier aggregation scenario. Each eNB (serving eNB and non-serving eNB) has its own DRX parameters including onDurationTimer, drx-InactivityTimer, and drx-RetransmissionTimer, allowing independent configuration and management of DRX cycles for each eNB, thereby reducing the overall complexity of coordinating DRX across heterogeneous networks
Solution Approach 2:
The patent introduces a serving eNB as an intermediary that coordinates DRX operations between the UE and multiple eNBs. The serving eNB manages the DRX parameters and controls the timing of control channel receptions, acting as a mediator that simplifies the DRX management complexity for the UE while enabling efficient inter-eNB carrier aggregation operations
2Use of energy by moving object
If independent DRX operations are implemented for multiple serving cells belonging to different eNBs, then power consumption is reduced and uplink scheduling efficiency is enhanced, but the coordination of DRX parameters and synchronization of active time becomes more complex
Solution Approach 1:
The patent divides DRX operations into independent DRX cycles for each eNB, with separate parameter sets (onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer) configured for the serving eNB and non-serving eNB independently. This segmentation allows the UE to optimize power consumption by entering sleep modes specific to each eNB's DRX cycle while maintaining independent uplink scheduling efficiency for each cell group
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports its DRX state and active time information to both the serving eNB and non-serving eNB. This feedback enables the eNBs to coordinate their DRX parameters and synchronize active times, reducing the coordination complexity while maintaining the power consumption benefits of independent DRX operations
3Ease of operation
If carrier aggregation between different eNBs is implemented to provide offloading capability, then device efficiency is improved, but the difficulty of determining control channel reception times and managing random access increases
Solution Approach 1:
The patent designates a serving eNB as an intermediary that centralizes the control channel reception time determination for inter-eNB carrier aggregation. The serving eNB provides unified timing information and control channel configuration to the UE, eliminating the complexity of independently determining reception times from multiple eNBs while maintaining device efficiency through coordinated offloading
Solution Approach 2:
The patent merges the control channel reception time determination function into a unified mechanism managed by the serving eNB, combining the timing information from multiple eNBs into a single coordinated schedule. This merging simplifies the UE's task of determining when to receive control channels while enabling effective offloading to non-serving eNBs
Data Source
AI summary
Embodiments of user equipment (UE) and methods for enhanced discontinuous reception (DRX) operations for inter eNB carrier aggregation (CA) in an LTE network are generally described herein. In some embodiments, a UE is configured to be served by multiple serving cells. The first set of the serving cells may be associated with a first eNB and a second set of serving cells may be associated with a second eNB. In these embodiments, DRX operations may be performed independently in multiple serving cells belonging to the different eNBs. Other embodiments for enhanced DRX operations are also described.