Cell DRX Handover for Low-Latency Emergency Call Uplink
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Solution Overview
Problem
In wireless communication systems, there is a challenge in efficiently handling emergency calls during cell discontinuous reception (DRX) due to latency and resource constraints, which can lead to delayed transmission and increased network power consumption.
Innovation Solution
A method and apparatus for performing handover to a second cell during the DRX off-duration in a wireless communication system, allowing the transmission of emergency calls, with the UE receiving Cell DRX information including on-duration and off-duration, and initiating handover to a designated cell for emergency calls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If cell DRX off-duration is implemented to save network power, then network power consumption is reduced, but emergency call transmission is delayed
Solution Approach 1:
The patent applies preliminary action by having the UE prepare and store emergency call information during the DRX off-duration before the actual transmission opportunity arises. The UE maintains readiness to transmit emergency calls immediately when the DRX cycle allows, pre-positioning the transmission capability without requiring continuous network monitoring during off-duration periods.
Solution Approach 2:
The patent implements dynamics by enabling the UE to dynamically adjust its transmission behavior based on the DRX cycle state. When in off-duration, the UE can initiate handover procedures in advance and prepare transmission resources, then switch to active transmission mode when the network becomes accessible, creating a flexible adaptive system that balances power saving with emergency transmission needs.
2Loss of time
If handover is performed during DRX off-duration for emergency calls, then transmission latency is reduced, but network resource allocation becomes more complex
Solution Approach 1:
The patent extracts the emergency call transmission function from the normal DRX cycle operation. By identifying and separating emergency call handling as a special case, the system can apply simplified rules: the UE autonomously determines when emergency calls need transmission, initiates handover to appropriate cells, and manages resources without requiring complex network coordination during the off-duration period.
Solution Approach 2:
The patent introduces the UE as an intermediary that bridges the gap between the DRX power-saving mechanism and emergency transmission requirements. The UE acts as a mediator by locally managing emergency call Queues, determining optimal transmission timing, and coordinating handover decisions, thereby simplifying network resource allocation while enabling low-latency emergency communication.
3Reliability
If uplink signal transmission is allowed during DRX off-duration, then emergency call reliability is improved, but network power consumption increases
Solution Approach 1:
The patent applies local quality by differentiating the treatment of normal traffic versus emergency calls within the DRX cycle. For emergency calls, the system maintains enhanced reliability by allowing transmission during off-duration periods, while normal traffic continues to follow standard DRX power-saving procedures. This localized approach ensures emergency call reliability without universally increasing network power consumption across all traffic types.
Data Source
AI summary
The present disclosure relates to a method of performing operations in a radio resource control (RRC) CONNECTED state for a User Equipment (UE) in a wireless communication system. In particular, the method includes receiving Cell discontinuous reception (DRX) information including a Cell DRX on-duration and a Cell DRX off-duration, wherein a first cell is not expected to receive an uplink signal within the Cell DRX off-duration; based on the emergency call occurring within the Cell DRX off-duration, initiating a handover to a second cell; and transmitting at least one signal for the emergency call to the second cell upon a completion of handover.