Short Message Delivery in Extended Idle Mode DRX
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Solution Overview
Problem
Current mobile communication networks face challenges in efficiently delivering mobile-terminated short messages to User Equipments (UEs) in extended idle mode Discontinuous Reception (eDRX), leading to increased power consumption and signaling overhead, particularly due to unsynchronized message delivery and potential unreachable UE scenarios.
Innovation Solution
The proposed solution involves modifying the call flow to include additional parameters such as SM-Delivery-Timer and SM-Delivery-Start-Time in the MT-Forward-Short-Message-Request, and introducing a Maximum-UE-Availability-Time in Notify and Alert Service Centre Request messages to ensure synchronized retransmission and reduce signaling overhead, along with an optional procedure using a Max Retransmission Time AVP to manage retransmissions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If extended idle mode DRX is applied to lower power consumption, then power consumption is reduced, but message delivery reliability deteriorates due to UE unreachability
Solution Approach 1:
The network side performs preliminary actions by storing the short message in the HSS and setting the MNRF flag before the UE wakes up. The SM-Delivery-Timer is configured to trigger automatic retransmission at the appropriate time when the UE becomes reachable, eliminating the need for continuous monitoring and ensuring reliable delivery without compromising power savings.
Solution Approach 2:
The HSS acts as an intermediary by temporarily storing the short message and managing the delivery timing. It coordinates between the SMS-GMSC and the UE through standardized interfaces (Diameter protocols), ensuring the message is delivered at the optimal time when the UE is reachable while maintaining network efficiency.
2Reliability
If traditional MT SMS procedure is used for UEs in eDRX, then message delivery is attempted, but signaling overhead increases due to repeated failed deliveries and notifications
Solution Approach 1:
The invention extracts the message delivery management function from the MME and places it in the HSS. The HSS independently manages message storage, timing, and retransmission by storing the SM and controlling the SM-Delivery-Timer, thereby removing unnecessary signaling loops between MME, SGSN, and HSS that would otherwise increase overhead.
Solution Approach 2:
The system implements self-service through automated timer-based retransmission. The SM-Delivery-Timer automatically triggers message retransmission at the HSS without requiring manual intervention or additional signaling protocols, reducing the burden on network elements and minimizing signaling overhead while ensuring reliable delivery.
3Productivity
If message retransmission is performed without timing coordination, then delivery attempts are made, but delivery precision deteriorates due to unsynchronized retransmission
Solution Approach 1:
The invention introduces precise timing parameters (SM-Delivery-Timer, SM-Delivery-Start-Time) to control message retransmission. These parameters are configured based on the UE's eDRX cycle and wake-up patterns, ensuring messages are retransmitted at the optimal moment when the UE is guaranteed to be reachable, thereby achieving both speed and timing precision.
Data Source
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AI summary
An embodiment is a mobile network entity capable of receiving a TFR (MT-Forward-Short-Message-Request) message forwarding a SM (Short-Message) towards a User Equipment (UE), said mobile network entity configured to: - upon reception of a TFR message forwarding a SM towards a UE in extended idle mode DRX (Discontinuous Reception), including a SM-Delivery-Timer/Start-Time indicating the time used in the SM gateway SMSC to supervise the receipt of the TFA (MT-Forwa rd-Short-Message-Answer) message, keep the SM for a specified time if the UE is expected to become reachable before the expiration of said timer, and page the UE, - if the UE responds to this paging during this specified time, deliver the SM to the UE, - if the UE does not respond to this paging during this specified time, or if the UE is not expected to respond within this time, send towards a SM gateway SMSC a delivery failure and set a flag to record that the UE is currently not reachable.