MTC Device Backoff Time Management for Network Load Control
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Solution Overview
Problem
In 3GPP systems, when multiple MTC devices attempt access simultaneously, the radio access network load increases, leading to instability and initial access failures, as existing methods lack effective mechanisms to manage backoff times and restrict access efficiently.
Innovation Solution
A method where MTC devices receive a Backoff Indicator (BI) from the base station, allowing them to delay initial access attempts based on a calculated backoff time, which can be applied selectively to reduce network load and restrict access, using a common RA-RNTI for MTC devices to acquire RAR scheduling information without initial preamble transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple MTC devices attempt access simultaneously using legacy random access technique, then initial access can be established, but the radio access network load increases abruptly causing network instability and access failures
Solution Approach 1:
The patent applies preliminary action by implementing access barring checks before the actual random access attempt. MTC devices perform category identification and evaluate access conditions (such as checking access barring parameters, determining whether to apply backoff time) before transmitting the random access preamble. This preliminary evaluation prevents simultaneous access attempts that would cause network overload, thereby maintaining network stability while still allowing legitimate access requests to proceed.
2Reliability
If backoff time is applied after Random Access Preamble transmission in legacy technique, then access network load can be controlled, but the initial access itself cannot be restricted effectively
Solution Approach 1:
The patent moves the load control mechanism from post-transmission (after preamble) to pre-transmission (before preamble). By performing category identification and access barring evaluation before the random access preamble transmission, the system can prevent excessive access attempts from occurring in the first place. This preliminary restriction is more effective than post-transmission backoff because it stops the harmful behavior before it contributes to network overload.
Solution Approach 2:
The patent introduces an intermediary mechanism (category identification and access barring parameter evaluation) between the MTC device's access desire and the actual random access transmission. This intermediary layer acts as a filter that evaluates whether the device should proceed with access based on current network conditions and device category, thereby effectively restricting initial access when necessary without directly controlling the transmission timing.
3Ease of operation
If MTC devices perform access attempts without category-based access barring, then access simplicity is maintained, but the ability to manage different MTC device characteristics is lost
Solution Approach 1:
The patent applies segmentation by dividing MTC devices into different categories based on their access characteristics and requirements. Each category can have specific access barring parameters and backoff time configurations. This segmentation allows the system to manage diverse MTC device characteristics (such as delay-tolerant vs. delay-sensitive devices) differently, providing adaptability while maintaining a relatively simple access procedure within each category.
Solution Approach 2:
The patent implements local quality by applying different access barring parameters and backoff time values to different MTC device categories rather than using a uniform approach. Each category receives customized access control parameters suited to its specific characteristics, allowing the system to optimize access management for each device type while maintaining overall system simplicity through standardized category-based handling.
Data Source
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AI summary
The present invention relates to a method comprising receiving, from a base station associated with a cell, a message including information on at least one public land mobile network (PLMN), parameter information related to an access barring corresponding to each of the at least one PLMN and application information on whether the parameter information related to the access barring is applicable for a terminal not in home PLMN(HPLMN) of the terminal for a corresponding PLMN. Identifying whether a PLMN for the terminal is included in the at least one PLMN. Performing, if the PLMN for the terminal is included in the at least one PLMN, an access barring check based on an access barring time and the application information, the access barring time being identified based on the parameter information related to the access barring corresponding to the PLMN for the terminal.