mobile network operator perspective. industry in … - mobile network... · company confidential...
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COMPANY CONFIDENTIAL
Mobile Network
Operator Perspective.
Industry in general,
Standards, Evolution.
ITSF 2009
Martin Kingston
Principal Designer, Transport
Orange UK
COMPANY CONFIDENTIAL
Mobile industry in general
Considering R99 UMTS architecture as a baseline, let’s
consider;
Where are we now?
Access
Core
What’s round the corner
Building on where we are now
Where are we going
LTE EPS
“True” IP and “Flatter” architectures
COMPANY CONFIDENTIAL
Control Plane
User Plane
Revision - UMTS Architecture and Interfaces3GPP R99
MSC/
MGW
RNC
Node B
RNC
Node B
G-MSC
SGSN GGSN
Node B
Node B
PSTN
Voice interconnects
Internet
PDNs
GRX
Iub
Iu-c
s
E
Iu-p
s
Gn
Gi
Gp
Iur
COMPANY CONFIDENTIAL
Control Plane
User Plane
UMTS Architecture and InterfacesBut what’s underneath the logical interfaces? Access first...
Gp
ATM and TDM
Core
Transport
Access
Transport
MSC/
MGW
RNC
Node B
RNC
Node B
G-MSC
SGSN GGSN
Node B
Node B
PSTN
Voice interconnects
Internet
PDNs
GRX
Iub
AT
MIu
-cs
E
AT
MIu
-ps
Gn
IPG
i
TD
M
COMPANY CONFIDENTIAL
Where are we now - Access
The long predicted impact of the uptake of mobile data services on mobile network access transport has arrived...
Significant increase in peak rates
Widespread rollout of HSPA
– HSDPA 7.2 and 14.4
– HSUPA 1.8 and latency reduction
More Cat 10 devices around
Significant increase in average rates
Many more users
User behaviour changes
– the “all you can eat” effect
The result is widespread adoption of packet based approaches in the access transport network.
Ethernet interfaces on base stations
Packet based aggregation to exploit peak / average contention
Packet leased services for lower cost
COMPANY CONFIDENTIAL
Packet based approaches for accessOUK examples for R99
ATM
POS / GBERNC
ADM
E1
E1
E1
E1
Ch
STM1Leased packet
TransmissionPOS / GbE POS / GbE
ATM
VC4
STM1
MGW
SGSN
RNC
ATM
ATM
Iu-b
Iu-cs
Iu-ps
Iu-r
LLU
Infrastructure
EFM
G.SHDSLbis
GbE
GbE
Leased E1
Transmission
ATM
Many
E1s
E1E1
E1
Iu-b
Aggregation
IP transport
IP/ATM<->IP/GbE
Transport over packet on DSL
Aggregation and transport over packet
Ethernet
E1
MLPPP
Eth /
E1Leased packet
TransmissionGBE
GBE
E1
Adaptation of interfaces Transport over packet on Leased service
COMPANY CONFIDENTIAL
Where are we now – Access
Widespread adoption of packet based approaches in the access transport network,
Ethernet interfaces on base stations (with ATM pseudowires, or IP TNL*)
Packet based aggregation to exploit peak / average contention
Packet leased services for lower cost,
is solving some immediate challenges, and the optimisation of transport in the access network is progressing well.
But the architecture of the Radio Access Network hasn’t changed much, so we still have control and User plane coupling and service specific bearer control;
Element scalability optimisation is challenging
Transport domain boundaries dictated by RAN elements
Access technology substitution is non-trivial
*It doesn’t matter to much which of these is used since in either case it is just transport, isolated from user plane by the UTRAN frame protocol.
COMPANY CONFIDENTIAL
Control Plane
User Plane
UMTS Architecture and InterfacesWhat’s underneath the logical interfaces? Now for the core...
Gp
ATM and TDM
Core
Transport
Access
Transport
MSC/
MGW
RNC
Node B
RNC
Node B
G-MSC
SGSN GGSN
Node B
Node B
PSTN
Voice interconnects
Internet
PDNs
GRX
Iub
AT
MIu
-cs
E
AT
MIu
-ps
Gn
IPG
i
TD
M
COMPANY CONFIDENTIAL
Where are we now - Core
Although they may have started from a pure R99 architecture,
operators faced scalability challenges much earlier in the core
network. Consequently many have already introduced some
evolutions;
R4 Bearer independent CS core
IP Transport Network Layer
VoIP transit (and interconnect soon)
Sigtran (signalling on IP)
R7 Direct Tunnel (One GTP-u Tunnel)
COMPANY CONFIDENTIAL
Control Plane
User Plane
UMTS Architecture and InterfacesR99 access, R4 core and Direct Tunnel
Gp
MGW
RNC
Node B
RNC
Node B
MGW
SGSN GGSN
Node B
Node B
PSTN
Voice interconnects
Internet
PDNs
GRX
Iub
Iu-c
s Nb
Iu-p
s
Gn
Gi
MSS
Mc
Mc
One GTP-u tunnel
Direct Tunnel
COMPANY CONFIDENTIAL
Gp
IP
Core
Transport
Access
Transport
MGW
RNC
Node B
RNC
Node B
MGW
SGSN GGSN
Node B
Node B
PSTN
Voice interconnects
Internet
PDNs
GRX
Iub
Iu-c
s Nb
Iu-p
s
Gn
Gi
MSS
Mc
Mc
Control Plane
User Plane
UMTS Architecture and InterfacesR99 access, R4 core and Direct Tunnel
COMPANY CONFIDENTIAL
Recap and what next?
To recap, operators typically have:
significant R99 legacy, particularly in the access domain.
Challenges in the access network being met by changes in transport, without
much change in RAN architecture.
Challenges in the core network being met by changes in transport coupled with
some architectural change “cherry picked” from releases up to 3GPP R7
Together these have achieved some separation of Call control, Bearer control,
and user planes and furthered the adoption of generic IP transport, so what’s
next?
COMPANY CONFIDENTIAL
Recap and what next?
Operators have achieved some separation of Call control, Bearer control, and
user planes. So what’s next? We need to consider what we are aiming for. Maybe
it is something like this:
Total separation of control and user planes
Ubiquitous IP transport
No architectural constraint on transport domains
Control Plane
User Plane
IP
Transport
Control
Services
GatewayAccess
point
Access
point
Interconnect
COMPANY CONFIDENTIAL
3GPP R8 and “LTE”
3GPPP R8 is a significant step towards this goal, including many things often referred to just
as LTE, but more correctly termed LTE-SAE (System Architecture Evolution).
LTE access
Support of alternative access technologies
The EPC (Evolved Packet Core) – note, packet only! voice support is IMS.
An EPC and an appropriate access technology is an EPS (Evolved Packet System)
Control Plane
User Plane
IP
Transport
Control
Services
GatewayAccess
point
Access
point
Interconnect
COMPANY CONFIDENTIAL
EPS Architecture and InterfacesPacket Switched domain only - No CS support.
Control Plane
User Plane
All interfaces use an IP TNL.
E-UTRAN consists of an eNB and nothing else, there is no access / core
demarcation to impose on the underlying transport network.
Control and user planes are mostly decoupled.
MME
eNB
SAE
GW
eNB
PDN
GW
eNB
IP Services
Internet
IMS etc.
X2
S5
PCRF
X2
S1
1
SG
i
Gx+
(S7)
Rx+
S1
-US
1-C
COMPANY CONFIDENTIAL
Summary
Implementing System Architecture Evolution will benefit
operators by
Enabling all IP transport with simplified network architecture
Distributing control and decoupling from user plane
Supporting multiple alternative access technologies
Incorporating IMS integrating services into a single (packet) domain
Together, these will enable more flexible scalable networks with
reduced time to market for new services and, last but certainly
not least, reduced cost to serve.
Further reading:
http://3gpp.org/releases
http://www.ngmn.org/nc/downloads/techdownloads.html
COMPANY CONFIDENTIAL
Thank You
ITSF 2009
Martin Kingston
Principal Designer, Transport
Orange UK