物联网信令分析

物联网信令分析附着流程附着流程的功能UE注册到EPS网络EPS/MM

上下文EPS/MM

上下文EPS承载上下文网络附着过程中会建立一个缺省的EPS承载，该承载提供永久的IP连接。MME和UE会创建EPS/MM上下文。S-GW和P-GW会创建EPS承载上下文EPS承载上下文Page3110.

Create

session

response附着流程New

MMES-GWP-GWeNodeBHSS1.

Attach

request7.

Update

location

AckCreate

session

requestCreate

session

requestOld

MME2.

Identification

req/rsp3.

Identity

req/rsp11.

Create

session

responseA.B.Authentication/Security/

ME

Identity

retrievaCl.Update

location

requestCancel location

/AckD.E.Page32附着流程S-GWP-GWeNodeB

New

MME

Old

MME

HSS12.

Initial

Context

Setup

Request

/

Attach

Accept16.

Attach

complete17.

Modify

Bearer

Request

/

ResponseUplink

and

downlink

dataRRC

Connection

Reconfiguration

/

CompleteInitial

Context

Setup

ResponseDirect

TransferF.G.Page33TAU跟踪区更新流程TAU流程的功能:更新用户EPS网络中的位置UE进入到UE注册的TA列表之外的一个新的TA时，会触发此流程。分配新的GUTIUE的状态和MME的状态从EMM-DEREGISTERED变迁为EMM-REGISTERED当用户处在ECM-IDLE状态时，通过TAU流程会用户建立用户面资源激活标志是用于在TAU流程中，UE请求激活所有已激活的EPS承载的无线和S1承载。Page141TAU流程的触发MME1S-GW1MME2S-GW2MME3TA

list

1TA

list

2TA

list

3TA

list

4Periodic

TAUIntra

MME

TAUInter

MME

TAU

withSGW

changeInter

MME

TAU

withoutSGW

change2.UE移动到网络为其分配的一组TA之外1.周期性TAU更新定时器超时Page142Inter-MME

TAU流程-SGW改变New

S-GWP-GWHSSeNodeB1.

TAU

requestNew

MME

Old

MME3.

Context

response8.

Modify

bearer

response9.

Create

session

responseA.Security

functionContext

Ack

B.Create

session

requestModify

bearer

requestC.2.

Context

requestB.从旧MME中获取UE上下文.C.S-GW和P-GW创建承载上下文Page143Inter-MME

TAU流程-SGW改变Old

S-GWP-GWeNodeBNew

MME

Old

MME

HSS10.

Update

location

request13.

Update

location

Ack11.

Cancel

location16.

TAU

accept12.

Cancel

location

AckD.E.D.更新在HSS上UE的位置Initial

Context

Setup

RequestInitial

Context

Setup

ResponseTAU

completeDelete

session

requestDelete

session

responsePage144用户跟踪(intra-MME

TAU)Page145IP

Dataover

NAS传输流程NB-IoTMMENB-IoTBSNB-IoT

P-GW1NB-IoTUERRCConnectionSetup

withNASPDU

and

Ack/RspInd23MME

checks

NASintegrity,

decrypts

data4

GTP-U

with

IPPacketNB-IoT

S-GW

5

GTP-UPacket

withIPpacket6

IPPacketIoTPlatform/AS上行MO

IPPacket发送NB-IoTMMENB-IoTBSNB-IoTP-GWNB-IoTUEMME

encrypts10

data,performs

integrityprotection9

GTP-Uwith

IPPacketNB-IoT

S-GW

87

IPPacketIoTPlatform/AS下行应答IP

Packet发送1112

DLInformationTransfer(NAS

PDU)GTP-UPacket

withIPpacketPage184NAS传送信令流程MMES-GWP-GWUE

eNodeB0.

UE

isECMIdleModify

BearerRequestModify

Bearer

ResponseModify

Bearer

ResponseUplinkdata9.

Downlink

dataRRC

Connection

establishment

(NAS DATA

PDU

withEBI)S1-AP

Initial

UE

Message

(

NAS Data

PDU

withEBI)Check

Integrity

and decrypts

dataModify

BearerRequest10.

DataencryptionandIntegrityprotection11.

Downlink

S1-AP

msgRRC

DL

Message

(NAS

data

PDU

with EBI)No

furtheractivitydetectedS1

release

procedure

(see

section

5.3.5)8.Uplinkdata9.

Downlinkdata(NAS

Data

PDU

with

EBI)11.

S1-AP

UE

context

releasecommandNAS传输信令流程Release

Assistance

InformationUE在NAS消息中可包含Release

Assistance

Information，向MME指示是否有下行数据传输（UL数据的Ack），MME会根据UE指示释放连接，减少无效等待时间。任何时候，UE在UL

data中都可携带Release

Assistance

Information。如果Release

Assistance

Information中指示没有下行数据，MME将上行数据传输给

SGW后就立即释放连接。如果Release

Assistance

Information中指示有下行数据，表示下一个下行报文就是应用层交互的最后一个报文，MME将下行数据传输给eNB后就立即发起释放连接,eNB在完成空口传输后释放连接。如果没有包含Release

Assistance

Information，或者Release

Assistance

Information中指示有下行数据，但eNB没有收到DLdata，eNB根据不活动定时器释放连接。Page187MO发送一个报文Page188MO发送一个需要应答的报文UEeNBMMERRCConnSetupRequestRRCConnSetupRRCConnSetupCompleteInitial

UEmessage(NAS

PDU

with

data)UEContextReleaseCompleteUEContextReleaseCommandRRCConnReleaseNASRelInfo:ACK_THEN_RELReleaseTriggerDownlinkNASTransportDLInformationTransferPage189MO交互多个报文UEeNB

MMERRC

Conn

Setup

RequestRRC

Conn

SetupRRC

Conn

Setup

CompleteInitialUE

message(NAS

PDU

with

data)NAS

RelInfo:

notincludedReleaseTriggerUE

Context

Release

CommandRRC

Conn

ReleaseUE

Context

Release

CompleteDownlink

NAS

Transport(NAS

PDU

with

data)DL

InformationTransfer(NAS

PDU

with

data)UL

InformationTransfer(NAS

PDU

with

data)NAS

RelInfo:

NO_ACKUplink

NAS

Transport(NAS

PDU

with

data)当UE和APP

Server间是“请求-应答-再请求-再应答”这种双向交互时：Page190优化点：UE进入Idle态，UE和基站仍然保存接入层上下文信息，使用RRC连接恢复过程恢复挂起的连接，降低从Idle态迁移到连接态的信令开销（LTE需要重建用户面连接）数据发送同LTE，仍然通过用户面UP发送MO数据传送流程（UP方案）Page191MT数据传送流程(CP方案)4.

Paging20.

S1

release

procedure(see

section5.3.5)18.UplinkdataUEeNodeBMMES-GWP-GW6.

S1-AP

Initial

UE

Message(

NAS

Service

reques)t0.UE

is

ECMIdle7.

Modify

Bearer

RequestModify

Bearer

RequestModify

Bearer

Response5..RRC

Connection

establishmen(tNAS

Service

reques)t19.No

further

activity

detected1.

Downlink

data

2.

Downlink

data

Notification2.

Downlink

Data

Notification

ACK3.PagingModify

Bearer

ResponseDownlink

data

Data

encryption

andIntegrity

protectionDownlink

S1-AP

msg

(NAS

DATA

PDU

with

EBI)RRC

DLmsg(NAS

PDU

with

data)RRC

ULmsg(NAS

PDU

with

data)UL

S1-APmsg(

NAS

DATA

PDU

with

EB)ICheck

Integrity

and

decrypts

dataUplink

data优化点：寻呼消息不再触发

LTE的Service

Request过程，而是触发RRC连接恢复过程数据发送同LTE，仍然通过用户面UP发送MT数据传送流程(UP方案)Page194案例一：MME配置错误导致NB-IOT测试用户附着失败某局点开通NB-IOT测试，设备调测完成后，使用测试终端拨测发现，用户附着失败；失败原因为：Page196案例一：MME配置错误导致NB-IOT测试用户附着失败当终端上报能力为NB-IOT设备时，MME会去比对终端签约的APN和ADDM2MPLCY中的APN配置，