Detached MTC Device Data Transmission via Gateway Buffering
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Solution Overview
Problem
Current LTE-Advanced systems do not support downlink data transmission to detached machine type communication (MTC) devices, leading to scheduling competition and resource exhaustion, which negatively impacts general users.
Innovation Solution
A data transmission method where a detached MTC device stands by in a paging channel receiving state, with the packet data network gateway maintaining its IP address and the mobility management entity triggering a paging procedure upon receiving downlink data from an MTC server, allowing the device to perform an attachment procedure and receive buffered data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MTC devices are treated as general terminals and individually registered in the network, then data transmission can be supported, but scheduling competition increases and radio resources are exhausted
Solution Approach 1:
The patent segments MTC devices into two categories: attached MTC devices (treated as general terminals with full registration) and detached MTC devices (not registered, using alternative delivery mechanism). This segmentation allows the system to handle different MTC device states differently, avoiding scheduling competition for detached devices while maintaining data transmission capability for attached devices.
Solution Approach 2:
The patent introduces the S-GW (serving gateway) as an intermediary that buffers downlink data for detached MTC devices and triggers paging procedures when data arrives. This intermediary mechanism enables data delivery to detached devices without requiring them to be registered or compete for scheduling resources, thus resolving the contradiction between data transmission capability and scheduling efficiency.
2Loss of energy
If MTC devices are maintained in detached state to reduce network overhead, then resource consumption decreases, but downlink data transmission becomes impossible
Solution Approach 1:
The patent applies preliminary action by having the S-GW buffer downlink data in advance when a detached MTC device is identified, and by pre-configuring the paging procedure to be triggered when data arrives. This allows the system to maintain devices in detached state (saving resources) while ensuring data delivery capability remains intact through these pre-prepared mechanisms.
Solution Approach 2:
The patent implements feedback through the paging procedure mechanism: when the S-GW receives downlink data for a detached device, it triggers a paging procedure that notifies the device to attach to the network. This feedback loop ensures that detached devices can still receive data by automatically transitioning to attached state when needed, thus maintaining reliability without continuous network resource consumption.
3Speed
If downlink data is transmitted to detached MTC devices without paging procedure, then data delivery speed increases, but device cannot receive data due to lack of network registration
Solution Approach 1:
The patent uses the S-GW as an intermediary that receives downlink data from the MTC server, identifies the device as detached, buffers the data temporarily, and then triggers the paging procedure to deliver the data. This intermediary approach maintains fast data delivery by avoiding unnecessary registration procedures while ensuring reliable reception through the structured paging and attachment mechanism.
Data Source
AI summary
Provided are a data transmission method for a detached machine type communication (MTC) device and a mobile communication system providing an MTC service. The method includes sensing an MTC device performing a detachment procedure from a network, when the MTC device being detached is sensed, storing, at a first gateway (GW), context information about the MTC device being detached from the network, storing, at the detached MTC device, context information that has been lastly allocated and used before the detachment, receiving, at the first GW, downlink data transmitted from an MTC server to the detached MTC device, and buffering the received data, transmitting a paging message to the detached MTC device, and performing, at the MTC device receiving the paging message, an attachment process to the network, and receiving the DL data buffered in the first GW.