Dynamic AMBR Adjustment in LTE Dual Connectivity
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Solution Overview
Problem
In dual connectivity scenarios of LTE Advanced systems, the existing methods for managing aggregate maximum bit rates (AMBR) between master and secondary base stations can result in sub-optimal data rate distribution, leading to unnecessary data loss and failure to meet the contracted data rate for user equipment, due to imbalances in communication bearers between base stations.
Innovation Solution
The system includes means for each base station to obtain and share information about the data rate and buffer status with the other base station, allowing dynamic adjustment of AMBR parameters to ensure that the aggregate data rate meets the user's subscription limits, by generating and providing bit rate-specific information based on the aggregate maximum bit rate and required data rate, thereby optimizing data throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If static AMBR parameters are assigned to master and secondary base stations, then configuration simplicity is maintained, but data rate distribution becomes sub-optimal leading to unnecessary data loss
Solution Approach 1:
The patent transforms static AMBR parameters into dynamic parameters that are continuously adjusted based on real-time buffer status information exchanged between base stations. The master base station receives buffer status reports from the secondary base station and dynamically recalculates AMBR values to optimize data throughput while preventing data loss.
Solution Approach 2:
The patent implements a feedback mechanism where the secondary base station reports its buffer status to the master base station, which then adjusts the AMBR parameters accordingly. This closed-loop control system ensures that AMBR values are continuously optimized based on actual network conditions, resolving the contradiction between simplicity and performance.
2Productivity
If AMBR parameters are dynamically adjusted based on real-time information, then data throughput is optimized, but information exchange and coordination overhead between base stations increases
Solution Approach 1:
The patent extracts only the essential buffer status information needed for AMBR calculation from the secondary base station, rather than exchanging complete network state data. This selective information extraction minimizes control signalling overhead while still enabling dynamic AMBR optimization for improved throughput.
3Measurement precision
If buffer status information is continuously exchanged between base stations, then data rate distribution is optimized, but signalling overhead and processing load increase
Solution Approach 1:
The patent implements periodic buffer status reporting between base stations rather than continuous real-time exchange. This periodic action maintains sufficient measurement precision for effective AMBR optimization while significantly reducing signalling overhead and processing time, thus resolving the contradiction between control accuracy and time loss.
Data Source
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AI summary
A communication system is disclosed, in which a mobile telephone has a control-plane connection to a first base station and communicates user data using at least one communication bearer provided via a second base station. The base stations are configured to exchange information relating to the data rate required for the mobile telephone via the second base station. The first base station derives, based on the exchanged information, an aggregated maximum bit rate (AMBR) parameter specific to the second base station and provides the derived AMBR parameter to the second base station for use in data rate enforcement for the mobile telephone's communications via the second base station.