ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

ITU/BDT
Arab
Regional
Workshop
on


ITU/BDT
Arab
Regional
Workshop
on


“4G
Wireless
Systems”


LTE
Technology


Session
6
:
LTE/SAE
Mobility
and
Session
Managment


Managment


Speakers
M.
Lazhar
BELHOUCHET
M
Hakim
EBDELLIM.
Hakim
EBDELLI
Date
27
.
29
January
2010


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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

Agenda


. LTE/SAE
Mobility
Areas
. Tki
Tracking
AAreas
. UE
Identifications
. LTE
Mobility
&
Connection
States
. EPS
Connection
Management
((CECM)
)
and
LTE
Radio
g
Resource
Control
States


. RRC
States
RRC
States


. LTE/SAE
Bearer
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

LTE/SAE
Mobility
Areas


.
Two
areas
are
defined
for
handling
of
mobility
in
LTE/SAE:
.
The
Cell
The
Cell


.
identified
by
the
Cell
Identity.
.
Tracking
Area
(TA)acking
Ar(TA)
Tr
ea


.
It
is
the
successor
of
location
and
routing
areas
from
2G/3G.
.
When
a
UE
is
attached
to
the
network,
the
MME
will
know
the
UE’s
position
on
tracking
area
level.
.
In
case
the
UE
has
to
be
paged,
this
will
be
done
in
the
full
tracking
area.
area.


. Tracking
areas
are
identified
by
a
Tracking
Area
Identity
(TAI)
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Tracking
Areas


HSS
TAI1
TAI1
TAI1
1 2
Tracking Area
MME
eNB
TAI2
TAI2
TAI2
TAI2
TAI1
TAI1
S-eNBTAI3
TAI3
TAI2
TAI2
TAI2
TAI2
TAI2
eNB
3
S eNB
TAI3
TAI3
TAI3
TAI3
TAI3
TAI3
MME
Cell Identity

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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
Tracking Areas: Use of S1.flex Interface
HSS
TAI1-2
MME
TAI2
TAI2
TAI1
TAI1
TAI1
eNB
TAI1-2
MME
Pooling
:
several
1 2 3
eNB
TAI2
TAI2
TAI2
TAI2
TAI2
TAI2
MME
handle
the
TAI2
TAI2
TAI2
TAI3
TAI3
TAI3
TAI3 S-MME
same
tracking
area
1 2 3
S-eNB
Cell Identity
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010 ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
UE
Identifications


. IMSI
. IIntternationall
Mobile
SbSubscribib
er
IdIdentity
ti
Mbil
tit


. S.TMSI
. SAE
Temporary
Mobile
Subscriber
Identity
. CC.RNTIRNTI
. Cell
Radio
Network
Temporary
Identity
. S1
APUEID
S1.AP
UE
ID


. S1
Application
Protocol
User
Equipment
Identity
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010 ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
UE
Identifications:
IMSI


.
IMSI:
International
Mobile
Subscriber
Identity.
.
Used
in
SAE
to
uniquely
identify
a
subscriber
world.wide.
.
Its
structure
is
kept
in
form
of
MCC+MNC+MSIN:
. MCC:
mobile
country
code
. MNC:
mobile
network
code
MNC:
mobile
network
code


. MSIN:
mobile
subscriber
identification
number
.
A
subscriber
can
use
the
same
IMSI
for
2G,
3G
and
SAE
access.
.
MME
uses
the
IMSI
to
locate
the
HSS
holding
the
subscribers
permanent
registration
data
for
tracking
area
updates
and
attaches.
IMSIMCC MNC MSIN
3 diggits 2 diggits 10 diggits

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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010 ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
UE
Identification:
S.TMSI


.
S.TMSI:
SAE
Temporary
Mobile
Subscriber
Identity
.
It
is
dynamically
allocated
by
the
serving
MME
(S.MME)
.
.
Its
main
purpose
is
to
avoid
usage
of
IMSI
on
air.
.
Internally
the
allocating
MME
can
translate
S.TMSI
into
IMSI
and
vice
versa
versa.


.
Whether
the
S.TMSI
is
unique
per
MME
or
per
TA
is
not
clear
yet.
.
In
case
the
S1
flex
interface
opption
is
used,
,
then
the
eNB
must
select
the
right
MME
for
a
UE.
This
is
done
by
using
some
bits
of
the
S.TMSI
to
identify
the
serving
MME
of
the
UE.
This
identifier
might
be
unique
MME
ID
or
a
form
of
MME
color
code
Under
investigation
MME
ID
or
a
form
of
MME
color
code.
Under
investigation.


S-TMSIMME-ID or
MME color code
32 bits
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

UE
Identifications:
C.RNTI


.C.RNTI:
Cell
Radio
Network
Temporary
Identity
CRNTIi
ll
tdb
th
NB
i
UE

.C.RNTI
is
allocated
by
the
eNB
serving
UE
when
it
is
in
active
mode
(RRC_CONNECTED)
.This
is
a
temporary
identity
for
the
user
only
valid
within
the
servingg
cell
of
the
UE.
.It
is
exclusively
used
for
radio
management
procedures

procedures.
.X.RNTI
identifications
under
investigation.


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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

UE
Identifications:S1.AP
UE
ID


.
S1.AP
UE
ID:
S1
Application
Protocol
User
Equipment
Identity.
.
Two
additional
temporary
identifiers
allocated
by
eNB
andTwo
additional
temporary
identifiers
allocated
by
eNB
and
MME:


.
eNB
S1.AP
UE
ID
.
MME
S1.AP
IEID
.
Their
purpose
is
to
allow
efficient
implementation
of
S1
control
signaling
(S1AP=S1
Application
Protocol)
.
They
shall
allow
easy
distribution
of
S1
signaling
messages
iid
MME
dNBinside
MME
and
eNB.


.
NOTE:
This
concept
is
similar
to
SCCP
local
references
known
from
Iu
or
A
interface
in
3G/2Gfrom
Iu
or
A
interface
in
3G/2G.


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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010 ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
UE
Identifications
Summary


MCC

MCC

TAI1
TAI1
TAI1
TAI1
MNC MSIN
TAI2
TAI2
TAI2
TAI2
TAI2
TAI2
TAI1
TAI1 eNB
Cll Id i
C-RNTI
eNB S1-AP UE-ID | MME S1-AP UE-ID TAI2
TAI2
TAI2
TAI3
TAI3
eNBTAI2
Cell Identity
I3
TAI2
TAI2
S-MME
32
MME Identity
1
IMSI International Mobile Subscriber Identity
S-eNB
TATAI3
TAI3
TAI3 S MME
HSS
IMSI
MNC MSIN MME
1 2 3
S-TMSI

MME ID or

S-TMSI S-Temporary Mobile Subscriber Identity
C-RNTI Cell Radio Network Temporary Identity
S-MME Serving MME
S-eNB Serving E-Node B
TAI Tracking Area Identity (MCC+MNC+TAC)

MME-ID or
MME color code
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

Terminology
for
3G
&
LTE:
Connection
Mobility
Management


Mobility
Management



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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

LTE
Mobility
&
Connection
States


. There
are
two
sets
of
states
defined
for
the
UE
b
d
th
if
ti
hldb
th
MME
based
on
the
information
held
by
the
MME.


. These
are:
. 1.EPS*
Mobility
Management
(EMM)
states
2EPS*
Connection
Management
(ECM)
states
2.EPS
Connection
Management
(ECM)
states


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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

EPS
Mobility
Management
(EMM)
states


EMM.DEREGISTERED:


In
this
state
the
MME
holds
no
valid
location
information
about
the
UE
MME
may
keep
some
UE
context
when
the
UE
moves
to
this
state
(
to
avoid


MME
may
keep
some
UE
context
when
the
UE
moves
to
this
state
(e.g.
to
avoid
the
need
for
Authentication
and
Key
Agreement
(AKA)
during
every
attach
procedure)
Successful
Attach
and
Tracking
Area
Update
(TAU)
procedures
lead
to
transition
to
EMM.REGISTERED


EMMEMM.REGISTEREDREGISTERED:


In
this
state
the
MME
holds
location
information
for
the
UE
at
least
to
the
accuracy
of
a
tracking
area

accuracy
of
a
tracking
area
In
this
state
the
UE
performs
TAU
procedures,
responds
to
paging
messages
and
performs
the
service
request
procedure
if
there
is
uplink
data
to
be
sent.


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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
EPS Mobility Management (EMM) states
Attach
EMM
deregistered
EMM
i t d
registered
Detach
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010 ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
EPS
Connection
Management
(ECM)
and
LTE
Radio
Resource
Control
States


Resource
Control
States


UE
and
MME
enter
ECM.CONNECTED
state
when
the
signaling
connection
is
established
between
UE
and
MME
UEand
E.UTRAN
enter
RRC.CONNECTED
state
when
the
signaling
connection
is
established
between
UE
and
E.UTRAN



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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

EPS
Connection
Management
(ECM)
states


ECM.IDLE:


In
this
state
there
is
no
NAS
signaling
connection
between
the
UE
and
the

In
this
state
there
is
no
NAS
signaling
connection
between
the
UE
and
the
network
and
there
is
no
context
for
the
UE
held
in
the
E.UTRAN.
The
location
of
the
UE
is
known
to
within
the
accuracy
of
a
tracking
area
Mobility
is
managed
by
tracking
area
updates.


ECM.CONNECTED:


In
this
state
there
is
a
siggnalingg
connection
between
the
UE
and
the
MME
which
is
provided
in
the
form
of
a
Radio
Resource
Control
(RRC)
connection
between
the
UE
and
the
E.UTRAN
and
an
S1
connection
for
the
UE
between
th
EUTRAN
dth
MME


the
E.UTRAN
and
the
MME.
The
location
of
the
UE
is
known
to
within
the
accuracy
of
a
cell.
Mobility
is
managed
by
handovers.


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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

RRC
States


.
RRC_IDLE:
.
No
signalling
connection
between
the
UE
and
the
EUTRAN.
.
I.e.
:
PLMN
Selection.
.
UE
Receives
syystem
information
and
listens
for
Paging.
.
Mobility
based
on
Cell
Re.
selection
performed
by
UE.
selection
performed
by
UE.


.
No
RRC
context
stored
in
the
eNB.
.
RACH
procedure
used
on
RRC
RACH
procedure
used
on
RRC
connection
establishment.


.
RRC_CONNECTED:
.
UE
has
an
E.UTRAN
RRC
connection.
.
UE
has
context
in
E.UTRAN
(CRNTI
allocated)
.
E.UTRAN
knows
the
cell
which
the
UE
belongs
to.
.
Network
can
transmit
and/or
receive
data
to/from
UE.
receive
data
to/from
UE.


.
Mobility
based
on
handovers
.
UE
reports
neighbour
cell
measurements
measurements


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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010 ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
EPS
Connection
Management


ECM Connected= RRC Connected + S1 Connection

ECM Connected RRC Connected S1 Connection

UE

eNB

RRC Connection


S1 Connection

MME
ECM Connected


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EMM&ECMStatesTransitionsRegistration (Attach)
Allocate C-RNTI, S_TMSI
Allocate IP addresses
Authentication
Release RRC connection
Release C-RNTI
Release due to
Inactivity
EMM_Registered
Authentication
Establish security context
Configure DRX for paging
Power On
EMM_Deregistered
EMM_Registered
ECM_Idle ECM_Connected
ECM_Idle
Deregistration (Detach)
Change PLMN
Establish RRC Connection

Release C-RNTI, S-TMSI

Allocate C-RNTI

Release IP addresses
Release S-TMSI
Release IP addresses


New Traffic
Timeout of Periodic TA
Update
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
EMM & ECM States Summary
EMM_Deregistered
ECM_Idle
Network Context:
EMM_Registered
ECM_Connected
Network Context:
all EMM_Registered
ECM_Idle
Network Context:
security keys
no context exists
Allocated IDs:
IMSI
info for ongoing
transmission/reception
Allocated IDs:
IMSI, S-TMSI per TAI
1 several enable fast transition to
ECM_CONNECTED
Allocated IDs:
IMSI, S-UE Position:
unknown to network
Mobility:
PLMN/ ll l ti
or IP addresses
C-RNTI
UE Position:
known on cell level
S TMSI per TAI
1or several IP addresses
UE Position:
known on TA level (TA list)
cell selection
UE Radio Activity: none
Mobility:
NW controlled handover
UE Radio Mobility:
cell reselection
Activity: UE Radio Activity:
DL w/o DRX
UL w/o DTX
DL DRX for paging
no UL
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010 ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
LTE/SAE
Bearer


.
Thhe
maiin
ffunctiion
off
every
mobilbile
radio
telecommunication
network
is
to
provide
subscribers
with
transport
bbearers
ffor
theiir
user
data.
th
dt


.
In
circuit
switched
networks
users
get
a
fixed
assigned
portion
of
the
t
k’
bd
idth


network’s
bandwidth.


.
In
packet
networks
users
get
a
bearer
with
a
certain
quality
of
service
(QoS)
ranging
ffrom
fdfixed
guaranteedd
bandwidth
down
to
best
effort
services
without
any
guarantee.
.
LTE/SAE
is
a
packet
oriented
system
PDN GW


PDN GW



LTE/SAE
Bearer



UE


www.cert.nat.tn22 LTE/SAEMobilityandSessionManagment

ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010
SAE
Bearer
Architecture


SAEB th lt t kf UE EUTRAN dEPS t th

SAE Bearer spans the complete network, from UE over EUTRAN and EPS up to the
connector of the external PDN.

The SAE bearer is associated with a quality of service (QoS) usually expressed by a
label or QoS Class Identifier (QCI). label or QoS Class Identifier (QCI).

cell
S1-U
LTE-Uu
S5
PDNSgi
Serving
Gateway
PDN
Gateway
cell
eNB
End-to-End Service
SAE Bearer Service (EPS Bearer) External Bearer
Service
SAE Radio Bearer Service (SAE RB) SAE Access Bearer Service S5/S8 Bearer Service
Physical Radio Bearer Service S1 Physical Bearer Service
E-UTRAN EPC PDN
E UTRAN
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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

SAE
Bearer
Sections


.
S5/S8
bearer
.
Between
the
PDN
GW
and
SAE
GW.
.
This
is
usually
a
GTP
or
MIP
tunnel
between
the
two
network
elements.
.
SAE
Access
Bearer
Between
eNB
and
SAE
GW.
The
SAE
Access
Bearer
is
implemented
using
the
2G/3G
GTP
protocol
which
The
SAE
Access
Bearer
is
implemented
using
the
2G/3G
GTP
protocol
which
builds
a
GTP
tunnel
between
eNB
and
SAE
GW.


.
The
setup
of
this
SAE
Access
Bearer
is
managed
by
the
MME.
.
SAE
GW
andd
eNB
ddo
not
directlly
exchhange
siignaling
to
create
iit.
di
li


.
Radio
bearers
Between
UE
and
eNB.
.
The
eNB
connects
a
radio
bearer
internallyy
with
the
associated
SAE
access
bearer
on
S1.
U
interface.
.
The
mapping
of
radio
bearers
to
physical
resources
on
the
air
interface
is
the
major
task
of
the
task
of
the
eNB
scheduler.
.
major
eNB
scheduler

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ITU/BDT Arab Regional Workshop on “4G Wireless Systems” -Tunisia 2010

Thanks
for
your
Attention


Thanks
for
your
Attention


www.cert.nat.tn25 LTE/SAEMobilityandSessionManagment