Base Station Mobility Parameter Adjustment for High Traffic Handover
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Solution Overview
Problem
In wireless communication systems, low-speed terminals connected to base stations at cell edges experience delayed handover due to long 'time to trigger' (TTT) parameters, leading to potential disconnection when the base station transitions to high traffic states and reduces cell coverage, causing ping-pong effects and load imbalance.
Innovation Solution
A base station apparatus with a traffic determination unit and parameter generator adjusts mobility parameters by setting the smallest or highest parameter values across all speed regions when traffic exceeds a threshold, allowing low-speed terminals to quickly hand over to neighboring stations, thereby maintaining connection and dispersing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station uses a long TTT parameter for low-speed terminals to prevent ping-pong effects, then handover stability is improved, but handover delay increases and connection may be lost when cell coverage is reduced during high traffic states
Solution Approach 1:
The patent applies dynamics by making the TTT parameter adjustable rather than fixed. The base station dynamically changes the TTT parameter for low-speed terminals based on traffic state: using a first (longer) TTT parameter during normal traffic to prevent ping-pong, and switching to a second (shorter) TTT parameter during high traffic to enable faster handover before cell coverage reduction causes disconnection. This dynamic adaptation resolves the contradiction between handover stability and handover speed.
Solution Approach 2:
The patent directly applies parameter changes by modifying the TTT parameter value based on traffic conditions. The base station determines traffic state and accordingly selects different TTT parameter values for low-speed terminals. This parameter change allows the system to optimize handover behavior for different operational scenarios, preventing both ping-pong effects and connection loss due to delayed handover.
2Productivity
If the base station reduces cell coverage during high traffic states to offload users, then load balancing is improved, but low-speed terminals may experience disconnection due to delayed handover
Solution Approach 1:
The patent applies preliminary action by having the base station proactively identify low-speed terminals and adjust their TTT parameter before cell coverage reduction occurs. When high traffic state is detected, the base station preemptively shortens the TTT parameter for low-speed terminals, enabling them to complete handover to neighboring cells before the cell coverage is reduced. This preliminary parameter adjustment ensures connection maintenance while allowing load balancing through cell coverage reduction.
3Adaptability or versatility
If the base station uses differentiated TTT parameters for different terminal speeds, then handover performance for various speeds is improved, but system complexity increases
Solution Approach 1:
The patent applies local quality by differentiating TTT parameters specifically for low-speed terminals while maintaining uniform parameters for other terminals. The base station identifies low-speed terminals based on their movement characteristics and applies specialized parameter management only to this subset. This localized differentiation improves handover performance for low-speed terminals without requiring complex parameter management across all terminals, thus balancing adaptability and system complexity.
Data Source
AI summary
A base station apparatus includes a traffic determination unit, a parameter generator and a setting information transmitter. The traffic determination unit determines whether a traffic amount is larger than a threshold. The parameter generator generates, when the traffic amount is larger than the threshold, indicator information indicating to the terminal to use a parameter set to a parameter region corresponding to a highest moving speed in mobility parameters to which a parameter decreasing with increasing moving speed of the terminal is set to a plurality of parameter regions respectively corresponding to a plurality of moving speeds of the terminal. The setting information transmitter transmits the indicator information to at least one terminal.