At our 5th Telecoms Evangelist meet up Andy Sutton of EE gave a fantastic presentation reviewing the latest trends and developments in mobile backhaul architecture, strategy and technology. Starting with a review of backhaul capacity, performance requirements and protocol architecture, the presentation initially focused on the macro cell layer before going on to discuss options for evolving towards a true multi-layered heterogeneous network. Take a look!

1. 18/06/2013
1
Multi-RAT mobile
backhaul for Het-Nets
Andy Sutton
Principal Network Architect
Network Strategy
19th June 2013
Contents:
1. Brief overview of EE
2. Introduction to multi-RAT, multi-vendor
backhaul
3. Understanding the capacity requirements
for current and future backhaul
4. Ensuring high performance and low latency
backhaul implementationp
5. Evolving backhaul architecture to support
small cells and HetNets
6. Summary
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2. 18/06/2013
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Our Orange and T-Mobile inheritance
A marriage of two great companies, with strong brands and a combined subscriber base of over
29 million. Technology have played a strong role delivering synergies and positioning EE for
commercial and network leadership.
In September 2009 it was announced that France Telecom and Deutsche Telekom had agreed
to merge T-Mobile UK and Orange UK into a 50:50 joint venture to create the UK’s leading
mobile operator. The new company was officially formed on April 1 2010
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EE: THE BIGGEST AND BEST NETWORK
Europe’s fastest 4G rollout
> The UK’s first 4G network
− 4G in 80 cities and towns, and 55%
population coverage by June 2013population coverage by June 2013
− 98% 4G coverage by end of 2014
− Increasing depth of coverage and
capacity in the top 16 cities
> The UK’s biggest 3G network
− DC-HSDPA covering 75% of the
population (80% by December 2013)population (80% by December 2013)
− 3G HSPA+21 across 95% of the
population
> Fibre to 13m homes and businesses
> Evolving communication with VoWiFi,
VoLTE, RCSe, and service with quality
differentiation

3. 18/06/2013
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Mobile video consumption increases with 4G adoption
Arsenal vs Man City?
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Man U vs Liverpool?
KO 13:30
Arsenal vs Man City?
KO 16:00
What exactly is mobile backhaul…
• Mobile backhaul provides the control and user plane connectivity between
the radio base stations at the cell sites and associated network nodes on
the connectivity sites (edge of the core network)
• 2G – GSM BTS & BSC (Abis)
• 3G – UMTS NodeB & RNC (Iub)
• 4G – LTE eNB & SeGW, then on to EPC (S1) [+X2 transport]
• In addition, the backhaul network carries network control, operations and
maintenance traffic
• Mobile backhaul is evolving from TDM and ATM to all IP/EthernetMobile backhaul is evolving from TDM and ATM to all IP/Ethernet
• Mobile backhaul must scale to support the capacity requirements of the
RAN technologies – 2G/3G/4G, possibly WiFi too
• Mobile backhaul must meet strict performance criteria relating to latency,
packet delay variation and packet error loss rate
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GSM network architecture (HLR and databases not illustrated)
GERAN - GSM/EDGE Radio Access Network
2G
MSS
2G
BTS
2G
BTS
2G
BSC
+PCU
TRAU
/MGW
MGW
2G
BTS
2G
BTS
BSC
+PCU
SGSN GGSN
7
Red and blue lines refer to control and user plane
UMTS Network Architecture (HLR and databases not illustrated)
Over time the CS & PS core have become common to both
2G & 3G Radio Access Networks
3G
MSS
3G
NodeB
3G
NodeB
3G
RNC
TRAU
/MGW
MGW
NodeB
3G
NodeB
RNC SGSN GGSN
Red and blue lines refer to control and user plane 8

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EPS - Evolved Packet System
LTE - Long Term Evolution / EPC - Evolved Packet Core
4G HSS4G
eNB
4G
eNB
MME
S-
GW
PDN-
GW
PCRF
HSS
R8 LTE specifies an IP TNL, eNBs support Ethernet connectivity
4G
eNB
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3GPP mobile backhaul interfaces
2G
BTS
3G
NodeB
4G
BSC
RNC
Abis interface
Iub interface
S1 interface
Telecoms Evangelist No.5 10
4G
eNB
EPC
S1 interface

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Mobile backhaul…
• Mobile backhaul is a complex subject, it’s far
more than “transmission”
• Developing a mobile backhaul architecture and
associated technical strategy requires a detailedassociated technical strategy requires a detailed
understanding of:
• Multiple mobile RAN technologies
• GSM/EDGE, UMTS/HSPA+ & LTE
• Tele-traffic theory and dimensioning
• in a post-Erlang environment
• Transport technologies
TDM (PDH SDH) Ethernet PWE3 IP ATM FR MPLS• TDM (PDH, SDH), Ethernet, PWE3, IP, ATM, FR, MPLS
• Physical layer transmission systems
• Fibre, Copper & Microwave
• Operations, administration, maintenance and
provisioning
• QoS, Synchronisation, regulation etc…
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Mobile backhaul traffic - high level representation
Group Flow
2G
CS voice
CS data
PS data
Control plane PTPControl plane
O&M
3G
rt‐DCH
nrt‐DCH
HSPA
Control plane
O&M
LTE
QCI 1
QCI 2
QCI 3
QCI 4
QCI 5
QCI 6
QCI 7
2G
BTS
3G
NodeB
4G
eNB
BSC
RNC
PTP
IEEE1588-2008
Precision Timing Protocol
Abis
Iub
S1 (+X2)
Telecoms Evangelist No.5 12
Q
QCI 8
QCI 9
S1 Control plane
O&M
X2 User Plane
X2 Control Plane
Mgmt
CSG O&M
Tx O&M
IP IGP etc.
Sync IEEE1588v2 PTP
eNB
SeGW
NMS
Microwave
IDU
OAM from
external equipment
microwave, routers etc.

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Protocol architecture
mobile backhaul user plane User
data
PDCP
User
data
User
data
• GSM IP based Abis
GSM UMTS LTE
P-TRAU
UDP
IP
GTP-u
UDP
IP
UDP
IP
RLC
MAC-d
HS DSCH FP
PDCP
• Proprietary implementation of IP
based Abis
• UMTS IP based Iub
• 3GPP R5 IP transport in UTRAN
Telecoms Evangelist No.5 13
IP Sec (ESP)
Outer IP
VLAN
Ethernet
IP Sec (ESP)
Outer IP
VLAN
Ethernet
VLAN
Ethernet
• LTE IP based S1 and/or X2
• 3GPP R8 Evolved Packet System
Underlying (physical) network
Mobile backhaul traffic - high level network diagram
2G
PTP
CSG - flexibility point - policy and QoS
implementation point - service enabler…
FE or GE - Serial bit stream
EE/H3G network share
via MBNL - 3G MORAN
splits Iu-cs/Iu-ps to
separate core networks
Single RAN base
stations are
available to support
2G, 3G and 4G – EE
use SRAN for
2G/4G whilst 3G is
2G Abis migrates from TDM to
IP therefore IPSec is
implemented to ensure
network service
2G
BTS
3G
NodeB
4G
eNB
BSC
RNC
SeGW
2G/4G whilst 3G is
on MORAN Node B
Point to point
microwave radio
systems scale to
1Gbps+ in the
traditional
microwave bands
(6 - 42GHz)
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SeGW
NMS
Microwave
IDU2G
3G 4G
IDU
MASG - flexibility point - policy and QoS
implementation point - service enabler…
2G, 3G & 4G from a sub-tended site connected
by point to point digital microwave radio
Third party backhaul –
Optical fibre networks
delivering layer 2 and
layer 3 services
New <6GHz n/NLoS backhaul radios, V and E band systems along with new mesh concepts

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Real LTE deployment in multi-RAT network
- Focus on mobile backhaul
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Backhaul capacity for Super Macros
• Macro cell evolution is the first step towards HetNets
• Super macros contain multiple RATs, including multi-band LTEp p
• Super Macros will typically contain 3 or 6 cell sectors
• Available spectrum includes:
• 2 x 5MHz @800MHz
• 2 x 45MHz @1800MHz
• 2 x 20MHz @2100MHz
• 2 x 35MHz @ 2600MHz
• Super macros may be standalone sites with ELL or hub sites for sub-
tended microwave connected sites
• Backhaul may support more than one MNO
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Optimising ‘end to end’ LTE traffic performance
User data rate/throughput, latency, PDV, PELR, availability…
Radio interface
Resource allocation
Retransmissions etc.
Microwave CSG Backhaul circuit S1 flex IP VPN EPC Peering
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UE
UE radio layer
Applications optimisation eNB processing MASG Security infrastructure SGi service LAN
External
networks
…and back…
Network evolution - Super Macros, Small cells and in-
building solutions…
Macro sitesMacro sites
Microcell Microcell
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Indoor
solutions
Hot spot Cell edge
Small Cells as an
underlay network
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Network evolution - Super Macros, Small cells and in-
building solutions…
Mobile backhaul may be integrated with the
macro network or, decoupled (complete off-
load) or, a hybrid of the two approaches…
19
Several factors will influence decisions – deployment timeline, RAT, spectrum
strategy and future network evolution strategy (co-ordination, C-RAN etc.)
Telecoms Evangelist No.5
Small cell backhaul architecture – two options
Backhaul could be fully integrated with the macro network or completely
decoupled with an overlay (underlay) solution
Integrated solution requires high-capacity macro layer backhaul howeverIntegrated solution requires high-capacity macro layer backhaul however
opens up future opportunities for coupling between layers
Dedicated backhaul decouples the traffic load between macro and small
cell backhaul solutions – may limit future options for co-ordination…
Requirements will change as we evolve from 3G to LTE small cells
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Small cell backhaul architectures
- integrated or decoupled…
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Macro backhaul not illustrated for clarity
Small cell backhaul architectures
- integrated or decoupled or a hybrid of the two…
Macro backhaul not illustrated for clarity
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Macro backhaul not illustrated for clarity

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Summary
•Many factors will influence mobile backhaul
evolution – technical, commercial, regulatory,
strategic…g
•Backhaul capacity needs to scale significantly to
support multi-RAT base station sites, particularly
if backhaul is shared between operators
•Single RAN platforms support Co-Tx of multiple
RAT backhaul over a single physical interface
Q lit f i i ‘ d t d’•Quality of experience is an ‘end to end’
consideration, however backhaul could have a
significant impact
•Small cells must integrate in a cost-optimised
manner, consider evolution to HetNets…
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THANKYOU
andy.sutton@ee.co.uk