# What is hysteresis?

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What is hysteresis?

In: Engineering

Hysteresis is repetitive motion/strain. Imagine stretching a rubber band, then letting it relax, then stretching it again, then letting it relax again. After this process is repeated ten, a hundred, a thousand, ten thousand times, the rubber band’s physical properties will change; it might get less stretchy each time, or maybe more stretchy.

And a mobile technology field hysteresis has a specific meaning for a retrial rhythm. It continues to try to deliver its data payload and circumvent technical obstacles. In my company’s communication device for Ice Road truckers, it can communicate via cellular, satellite, and Wi-Fi. From Erickson’s patent: A method in a cellular telecommunications network for optimizing a current hysteresis value utilized to define a handoff border between a present cell and a neighbor cell. Pairs of signal strength (SS) measurements are collected from a plurality of mobile stations operating near the handoff border. Each SS measurement pair includes an SS measurement from the present cell and an SS measurement from the neighbor cell. A midpoint SS is then calculated by determining an average SS measurement from the present cell, an average SS measurement from the neighbor cell, and an overall average of the average SS measurement from the present cell and the average SS measurement from the neighbor cell. The method then optimizes the handoff border by subtracting from the current hysteresis value, an amount approximately equal to the difference between the midpoint SS and the average SS measurement from the present cell.

Imagine you push your hand through a pool of water in one direction. There will be a wave one one side of your hand. Say, the left for this example.

Now, push your hand in the other direction. The wave will be on the right of your hand.

Your hand can be in the same place in both directions, but the effect of your hand being there (the wave) will be different. So, say your hand is at the midpoint. Wave 1 will be slightly to the left, wave 2 will be slightly to the right.

Essentially, the same absolute position (in a physical system) might not create the same output if travelling in the opposite, or a different, direction.

Edit: if you want a specific example for a certain type of engineering, feel free to ask and I will try ELY5 for it.