UE-Controlled E-UTRAN Mobility With Lower EPC Signaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing IoT devices face challenges with frequent state transitions between connected and idle states, leading to EPC signaling overload, battery life issues, and increased handover failures due to inefficient use of Connected mode discontinuous reception (C-DRX cycles, especially in fast-moving scenarios.
Innovation Solution
Introduce two new RRC states, ERA_PCH and CU_CNCTD, allowing IoT devices to move within an ERA or CU without frequent signaling, using X2 paging and Cell Update procedures to manage mobility, and buffer data at an Anchor eNB, minimizing S1 signaling and reducing handover failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If IoT UE is kept permanently in RRC_CONNECTED state, then uplink delay is reduced and handover performance is improved, but battery life deteriorates due to continuous measurements and signaling
Solution Approach 1:
The patent introduces a dynamic intermediate state (RRC_INACTIVE) that allows the system to adapt between fully connected and fully idle modes. The UE can transition to this state when data activity is low, reducing power consumption while maintaining quick reactivation capability for immediate data transmission when needed.
Solution Approach 2:
The patent applies different connectivity qualities to different operational scenarios. In RRC_INACTIVE state, the UE maintains minimal connectivity for fast reactivation while consuming less power, whereas in RRC_CONNECTED state, full connectivity is maintained for low-latency requirements. This localized quality adjustment optimizes the trade-off between delay and power consumption based on specific operational needs.
2Use of energy by moving object
If C-DRX cycle is extended for power saving, then battery life is improved, but handover performance deteriorates due to less frequent measurements
Solution Approach 1:
The patent makes the measurement frequency dynamic based on the RRC state. In RRC_INACTIVE state with extended C-DRX, measurements are performed less frequently to save power. However, when transitioning to RRC_CONNECTED or during active handover scenarios, measurement frequency increases automatically, ensuring handover reliability is maintained when needed while allowing power savings during inactive periods.
Solution Approach 2:
The patent changes the measurement parameter (measurement frequency) based on the operational state. By adjusting the C-DRX cycle length and corresponding measurement frequency according to whether the UE is in RRC_CONNECTED or RRC_INACTIVE state, the system optimizes the balance between power consumption and handover performance for different operational conditions.
3Use of energy by moving object
If frequent state transitions occur between EMM_Connected and EMM_Idle, then power consumption is reduced in idle state, but EPC signaling load increases
Solution Approach 1:
The patent extracts the RRC connection management from the EPC signaling path by introducing RRC_INACTIVE state managed at the RRC layer. State transitions between RRC_CONNECTED and RRC_INACTIVE are handled without EPC signaling involvement, thereby reducing EPC signaling load while maintaining power-saving benefits of idle-like states.
Solution Approach 2:
The RRC_INACTIVE state acts as an intermediary between RRC_CONNECTED and RRC_IDLE, providing a middle ground that reduces EPC signaling transitions. The UE can move to this intermediate state for power saving without triggering full EPC signaling sequences, and can quickly reactivate to connected state when needed, reducing the frequency of costly EPC state transitions.
4Use of energy by moving object
If UE performs measurements only during C-DRX receiving occasions, then power consumption is reduced, but handover failure rate increases in fast-moving scenarios
Solution Approach 1:
The patent implements dynamic measurement scheduling where the UE adapts its measurement frequency based on mobility detection. When the UE detects it is moving fast (through Doppler shift or cell reselection rate), it automatically increases measurement frequency even during C-DRX cycles, ensuring handover reliability is maintained in fast-moving scenarios while keeping power consumption low during stationary or slow-moving conditions.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Briefly, in accordance with one or more embodiments, a user equipment (UE) may enter into an E-UTRAN Routing Area Paging Channel state, and is configured with an E-UTRAN Routing Area and an Anchor identifier to identify an anchor evolved Node B (eNB) for the UE. The UE selects to a new cell without performing a handover procedure, and performs a cell update procedure. The UE also may enter into a Cell Update Connected state, and is configured with an Anchor identifier. The UE selects to a new cell, performs a cell update procedure, performs a buffer request procedure, and performs a cell update procedure to download buffered data and to perform data transmission with the new cell.