Base Station Overload Control via Dynamic Access Class Barring
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Solution Overview
Problem
Wireless communication networks face congestion due to the simultaneous access requests from machine-type communication (MTC) devices, leading to potential overload of base stations, which existing methods like Access Class Barring (ACB) struggle to manage effectively.
Innovation Solution
Implementing a method to detect potential network overload, selecting an access class for adjusting overload control information, and transmitting adjusted information through system information messages or paging messages, incorporating ACB and initial back-off mechanisms to regulate access and reduce congestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Access Class Barring (ACB) scheme is used to control MTC initial access, then network overload is reduced, but signaling efficiency deteriorates due to simultaneous access attempts
Solution Approach 1:
The base station transmits overload control information in advance through system information blocks before MTC devices attempt random access. This preliminary action allows devices to check overload conditions and delay access attempts proactively, preventing simultaneous access signaling storms while maintaining reliable overload protection
Solution Approach 2:
The system implements feedback mechanisms where the base station continuously monitors network load and dynamically adjusts overload control information (ac-BarringFactor, ac-BarringTime) which is broadcast to MTC devices. This feedback loop enables adaptive control that improves signaling efficiency by adjusting barring parameters based on actual network conditions rather than using fixed thresholds
2Speed
If MTC devices attempt to access network simultaneously, then service responsiveness is improved, but base station becomes overloaded
Solution Approach 1:
The base station applies preliminary anti-action by transmitting access barring information that actively prevents simultaneous access attempts before they occur. MTC devices read this information from system information blocks and apply back-off delays, counteracting the tendency to access simultaneously and protecting base station load capacity while maintaining reasonable access responsiveness
Solution Approach 2:
The overload control parameters are made dynamic rather than static. The base station can adjust ac-BarringFactor and ac-BarringTime values based on current network load conditions, allowing the system to adapt between permitting faster access when load is low and enforcing stricter delays when load is high, balancing responsiveness and load capacity
3Measurement precision
If ACB information is updated frequently, then network control accuracy is improved, but signaling overhead increases
Solution Approach 1:
The system uses periodic broadcasting of overload control information through system information blocks rather than continuous updates. This periodic action provides sufficient control accuracy by informing devices of current overload conditions at regular intervals while minimizing signaling overhead by avoiding redundant transmissions during stable network conditions
Data Source
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AI summary
A method for controlling network congestion is disclosed. A potential overload of the network is detected. An access class for which to change overload control information is selected. The overload control information is adjusted for the selected access class. The adjusted overload control information is then transmitted. The method may be performed by a base station.