想请教下，LTE协议中的normal tracking area 和combined tracking area有哪些区别？

-  normal tracking area updating to update the registration of the actual tracking area of a UE in the network;
-  combined tracking area updating to update the registration of the actual tracking area for a UE in CS/PS mode 1 or CS/PS mode 2 of operation;

详细的信令过程你可以阅读24.301协议。

CS/PS mode 1

CS/PS mode 2

有具体的解释吗？谢谢！！

A UE attached for EPS services shalloperate in one of the following operation modes:
-  PS mode 1 of operation: the UE registers only to EPS services, and UE's usage setting is "voice centric";
-  PS mode 2 of operation: the UE registers only to EPS services, and UE's usage setting is "data centric";
-  CS/PS mode 1 of operation: the UE registers to both EPS and non-EPS services, and UE's usage setting is "voice centric"; and
-  CS/PS mode 2 of operation: the UE registers to both EPS and non-EPS services, and UE's usage setting is "data centric".

A UE configured to use CS fallback, shall operate in CS/PS mode 1 or CS/PS mode 2. Such UE may also be configured to use IMS.

A UE configured to use SMS over SGs, but not configured to use CS fallback, shall operate in CS/PS mode 1 or CS/PS mode 2. 

Thank you