【请教】LTE如何区分某个service request是paging response还是mo-data/mo-signaling

hycl5410

如题。
W下service request是带service type的，可以区分该service request是哪种类型的。paging response，mo-data，mo-signaling...
但是到了EPC（24.301）service request就看不到这个指示了。那么MME如何来明确分辨某一个service request是哪种类型的呢？
个人觉得分辨这个还是有用的，因为是两种不同的触发条件（网络还是UE）。

hycl5410

admin 发表于 2012-8-6 21:33
找到答案了！在TS24.301的附录D.1。主要原因是为了尽最大可能减少延迟还有就是减少空口的负担（省一个字节都 ...

非常感谢！

hycl5410

hou3331 发表于 2013-1-23 16:10
我在attach request消息中看到RRC-Establishment-Cause: mo-Signalling (3)，这个是什么意思哦？为什么发起 ...

我在attach request消息中看到RRC-Establishment-Cause: mo-Signalling (3)，这个是什么意思哦？为什么发起UL signalling，消息类型也是MO-data？，If a SERVICE REQUEST is to request resources for UL signalling, the RRC establishment cause shall be set to MO data. (See Note 1)"originating calls"

规范还在24.301 D.1。

Table D.1.1: Mapping of NAS procedure to establishment cause and call type

	NAS procedure	RRC establishment cause (according 3GPP TS 36.331 [22])	Call type
	Attach	MO signalling (See Note 1)	"originating signalling"
	Tracking Area Update	MO signalling (See Note 1)	"originating signalling"
	Detach	MO signalling (See Note 1)	"originating signalling"
	Service Request	If a SERVICE REQUEST is to request user plane radio resources, the RRC establishment cause shall be set to MO data. (See Note1)	"originating calls"
		If a SERVICE REQUEST is to request resources for UL signalling, the RRC establishment cause shall be set to MO data. (See Note 1)	"originating calls"
		If a SERVICE REQUEST is a response to paging where the CN domain indicator is set to "PS", the RRC establishment cause shall be set to MT access. (See Note 1)	"terminating calls"
		If a EXTENDED SERVICE REQUEST has service type set to "mobile originating CS fallback", the RRC establishment cause shall be set to MO data. (See Note1).	"originating calls"
		If a EXTENDED SERVICE REQUEST has service type set to "mobile terminating CS fallback", the RRC establishment cause shall be set to MT access. (See Note1).	"terminating calls"
		If a EXTENDED SERVICE REQUEST has service type set to "mobile originating CS fallback emergency call", the RRC establishment cause shall be set to Emergency call. (See Note1).	"emergency calls"
Note 1:      For these NAS procedures initiated by UEs of access class 12, 13 or 14 in their home country, the RRC establishment cause will be set to "High priority access AC 11 – 15". For this purpose the home country is defined as the country of the MCC part of the IMSI, see 3GPP TS 22.011 [1A]. For these NAS procedures initiated by UE of access class 11 or 15 in their HPLMN or EHPLMN, the RRC establishment cause will be set to "High priority access AC 11 – 15".

NOTE:      The RRC establishment cause can be used by the network to prioritise the connection establishment request from the UE at high load situations in the network.

为什么这么设计呢？个人理解是为了区分优先级。一般对信令的处理要比数据的优先级高那么一些。而且NOTE里也这么提了。对于EPC来说，EMM-REGISTERED之后才可能有后续的信令流程，那么对EMM处理应该会给予优先。当UE进入ECM-IDLE后，并不影响EMM状态，所以service request流程给予data级别，即使UE想发起某些信令。