What is TAU storm and how this problem can be resolved ?

Question

It is well understood that Periodic TAU is used by MME to track UE location at the granularity of cell and tracking area.

Other than that, is there any reason of having periodic TAU procedure ?

Answer 1

When a huge no. of users move from one cell to another cell belonging to another TA and the respective tracking area has not been included in the assigned Tracking Area List to users. And all the users execute tracking area update procedure simultaneously.For example: when all the users are moving in a train.

There can be multiple solution for this problem but one solution which I would like to share with you is as following:
- Normally, network maintain tracking area list based on the cell , UE connects to the network.
- If network assign same tracking area list (TAL) to each user then there is a possibility for TAU storm.
- Network may put some intelligence based on the location of cell (near to railway station ), it may use to assign different TAL to each user to avoid TAU storm.