LTE中 detach发起的原因有哪些啊

The UE is detached either explicitly or implicitly:
- Explicit detach: The network or the UE explicitly requests detach and signal with each other.
- Implicit detach: The network detaches the UE, without notifying the UE. This is typically the case when the network presumes that it is not able to communicate with the UE, e.g. due to radio conditions.

Four detach procedures are provided when the UE accesses the EPS through E-UTRAN. The first detach procedure is UE-initiated detach procedure and other detach procedures are network-initiated detach procedure:
- UE-Initiated Detach Procedure.
- MME-Initiated Detach Procedure;
- SGSN-Initiated Detach procedure;
- HSS-Initiated Detach Procedure.

手机发起；
MME发起；
HSS发起

UE 发起去附着时原因有关机去附着和无EPS服务去附着。
MME发起去附着的情况是在建立一个紧急承载时进行的Attach后会跟随一个Detach过程，之后若UE进入正常的其他小区会进行重新Attach
HSS发起去附着的情况是UE已有一个紧急服务的承载，此时MME不能发起Detach过程，要去除不分配给紧急服务的承载时