Source Base Station Action Time Calculation for Handover Latency
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Solution Overview
Problem
Conventional WiMax handover procedures in wireless access networks experience increased latency due to the lack of consideration for backhaul propagation delay when determining action times for resource allocation during handovers from a source base station to a target base station.
Innovation Solution
The proposed solution involves calculating and incorporating backhaul propagation delay into the computation of action times by the source base station to accurately determine when the target base station can allocate uplink resources to the mobile station, thereby reducing handover delays by adjusting the action times to account for variable communication delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the target base station determines action time based on its current load without considering backhaul propagation delay, then the target base station can quickly allocate resources, but the handover latency increases due to unaccounted communication delays
Solution Approach 1:
The source base station performs preliminary calculation of the action time by incorporating the backhaul propagation delay before the handover occurs. The source base station receives the initial action time from the target base station, calculates the round trip time to the target base station, and determines a modified action time that accounts for communication delays. This preliminary adjustment ensures that the handover proceeds without unexpected delays caused by unaccounted propagation delays.
2Reliability
If the source base station increases the action time to account for potential delays, then handover reliability improves, but the handover latency increases
Solution Approach 1:
The source base station dynamically adjusts the action time parameter by calculating the round trip time to the target base station and modifying the initial action time accordingly. Instead of using a fixed or overly conservative action time, the system changes the parameter based on actual measured propagation delays, achieving optimal balance between reliability and latency.
3Device complexity
If the system uses conventional action time calculation without backhaul delay consideration, then the procedure is simple, but the handover performance is suboptimal
Solution Approach 1:
The source base station implements a feedback mechanism by measuring the round trip time to the target base station and using this information to adjust the action time. The system continuously monitors communication delays and incorporates this feedback into the action time calculation, ensuring optimal handover performance while maintaining a relatively simple procedural framework.
Data Source
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AI summary
To perform a handover of a mobile station from a source base station to a target base station, the source base station determines a delay of a connection between the source base station and the target base station. The source base station computes an action time taking into account the determined delay, the action time specifying a time when the target base station is able to allocate resources to the mobile station for the handover.