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© 2012 Cisco and/or its affiliates. All rights reserved. BRKSPM-3300 Cisco Public

LTE Networks: Design and Deployments BRKSPM-3300


1. Mobile Broadband Dynamics

2. LTE Networks Design

LTE Overall Architecture

LTE E-UTRAN

Mobile Backhaul Transport

LTE Gateways – MME, SGW, PGW

DNS and NAT

LTE QoS and Policy

3. LTE Network Deployments

Interworking, Roaming

Deployment Strategies & Best Practices

4. Summary & References

Agenda

LTE – Long Term Evolution, E-UTRAN: LTE radio interface, MME – Mobility Management Entity, SGW – Serving gateway, PGW – PDN Gateway, DNS – Domain name Server, NAT – Network Address Translation

2


Understanding from others and Making right assumptions

Apps and content providers

Social Media – P2P, Presence, Video sharing

Following experience from other LTE providers

Why care about Global Broadband Trends?

3

Service Provider Expectations

Monetizing the capacity

Optimizing investment and managing Total Cost of Ownership

Building simple, scalable and future proofing the network

Understanding user expectations – Seamless mobility & services

Maintaining same user experience in home and roaming networks

Providing different services, uninterrupted access to OTT


Mobile Broadband- Shifting the Focus?

4

Asia Pacific and Western Europe will account for over half of global mobile traffic by 2016

Middle East and Africa will experience the highest CAGR of 104 percent, increasing 36-fold by 2016

Mobile traffic projection is following natural population growth i.e. More mobile traffic in East

Though mobile traffic projection is higher in East, roaming traffic will put equal stress in other regions

LTE deployments started with Frequency Division Duplexing (FDD), however LTE using Time Division Duplexing (TDD) technology is growing significantly.

Source - Cisco VNI Report 2012 - 2116


Smart devices (smartphones & tablets account for nearly 60% of network traffic

Device capability – Operating System, features, OTT Apps drive data usages in smart devices. The trend will continue

Smart devices remains always connected and generate significant signaling traffic (e.g. mobility update, keepalive, network initiated updates)

Radio signaling overload due simultaneous device updates

Bandwidth hogging, Concurrent flows, Keeping NAT pin holes

Devices are more prone to malware (DOS/DDoS) attack


Traffic breakdown – based on Devices

Traffic multiplier compared to feature phone

Traffic based upon devices and Applications

5


IANA IPv4 address are depleted – Regional registries are allocating IPv4 business critical

More smart devices, more concurrent Apps needing more IP addresses

Availability of IPv6 capable smartphones is anticipated to grow over 43% CAGR

IPv6 deployed by many SP and positive results

Internal Apps and Mobile IPv6 penetration is increasing with LTE, VoLTE/IMS, M2M

May SP have deployed IPv6 is user plane. Few are doing IPv6 in user plane and transport

Global IPv6-Capable overall Mobile Devices


Mobile IPv6 Adoption

6





LTE E-UTRAN



DNS and NAT

LTE QoS and Policy





Agenda


7


SP Mobile Networks > Converging to LTE

8

<1999 2000-02 2006-07 2008-09 20010-11 2012+ 2003-04

3GPP Track

* Actual speed depend upon many factors

1xRTT

EDGE

Voice Data (9.6 - 56k)

Voice Data (9.6 - 56k)

Data (DL 2.4M) Voice 2x cap Data (144k)

Data (DL/UL 20/80k)

Voice (DL/UL 384/384k)

e-EDGE

UMB IS-95

LTE

(DL 1Mbps)

GSM

WiMAX

EV-DO RevB Multi-carrier Data (14.7M)

HSPA+

LTE Advanced

3G R99 HSDPA HSUPA

Enhanced modulation (DL 384k)

EV-DO RevA

(DL/UL 100/50M)

Optimized DL (14.4M)

Optimized UL (5.7M)

MIMO, 64QAM (DL/UL 42/11M)

GPRS

3GPP2 Track

Mobile Network Transformation to All IP

Architecture Harmonization

(3GPP R8) (3GPP R10+)

(DL/UL 1000/ 500M)


Simplified LTE/EPS Architecture

9

Radio Infrastructures Services End users

Cause – Efficient radio & capacity Effect - Need efficient infrastructure manage user & signaling data


LTE Design Objectives

10

High Peak Data Rates

100 Mbps DL (20 MHz, 2x2 MIMO)

50 Mbps UL (20 MHz, 1x2 MIMO)

5 bps/Hz for DL, 2.5 bps/Hz in UL

Spectrum Efficiency

3-4x HSPA Rel’6 in DL

2-3x HSPA Rel’6 in UL

Reduction in Capex/ Opex Open standard Flat IP architecture

Low Latency

< 5ms user plane (UE to RAN edge)

<100ms idle to active

Quality of Service

9 QoS classes mapped to DSCP

Tighter control between user &

transport

Interworking - UMTS/GSM/EvDO

Multimode LTE UE will Handover

HO time < 500ms for Non real time

HO time < 300ms for Real Time

Multicast/Broadcast Capable to support

enhanced MBMS

Spectrum Allocation Flexible spectrum 1.4, 3, 5, 10, 15, 20 MHz


Non-3GPP Access

3GPP Access

Evolved Packet System

LTE/EPS Architecture -(Ref 3GPP TS23.401, TS23.402)

11

E-UTRAN PDN

Gateway Serving Gateway

eNodeB

PCRF

Operator’s IP Services

HSS

Gxc (Gx+)

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN

S4 (GTP-C, GTP-U) UTRAN

SGSN

Trusted Non-3GPP IP Access

Untrusted Non-3GPP IP Access

S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5 (GTP-C, GTP-U)

Gx (Gx+)

Gxb (Gx+)

SWx (DIAMETER)

STa (RADIUS, DIAMETER)

ePDG

3GPP AAA

SWn (TBD)

S2c (DSMIPv6)

S2c

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa (TBD)

Gxa (Gx+)

Rx+

S2c

UE

UE

UE

SWu (IKEv2, MOBIKE, IPSec)

S2a (PMIPv6, GRE MIPv4 FACoA)

Trusted Untrusted*

LTE

2G/3G

Transport (Tunneled Traffic) IP Traffic

* SP WiFi is considered as trusted


National

Regional

Market

GGSN

SGSN

MSC

BSC

IP

TDM

FR/TDM

BTS

2G/2.5G 3G UTRAN

GGSN

MSC

RNC

IP

ATM

IP

NB

SGSN

3.5G UTRAN

GGSN

MSC

RNC

IP

IP

IP

NB

SGSN

LTE E-UTRAN

HSS PCRF

SGW

MME

IP

IP

eNB

PGW

MME – Mobility Management Entity, SGW – Serving Gateway, PGW – PDN Gateway

Hierarchical Architecture

Regionalizing mobile gateways





LTE E-UTRAN



DNS and NAT

LTE QoS and Policy





Agenda


13


Latest addition of 190MHz with lower & upper 70MHz for FDD and 50 MHz for TDD

LTE Frequency Bands (Ref TS36.101 (8) Table 5.5-1)

14


LTE Channels within Band (TS36.101, Fig 5.6-1 and table 5.6-1)

Channel bandwidth BWChannel

[MHz] 1.4 3 5 10 15 20

Resource Blocks(Transmission

bandwidth configuration NRB ) 6 15 25 50 75 100

Channel bandwidth (BWChannel) and the Transmission bandwidth configuration (NRB). Each NRB is also referred as resource block and 180KHz wide.

The channel edges are defined as the lowest and highest frequencies of the carrier separated by the channel bandwidth

15


…

FFT

5 MHz Bandwidth

Sub-carriers

Symbols

Guard Intervals

…

Frequency

Radio spectrum (1.4 MHz to 20 MHz) is divided into sub-carriers in frequency domain. Each sub-carrier is divided into frame and symbols in time domain Each OFDM symbol is independently modulated and transmitted Multiple users symbols are sent in parallel on available spectrum Guard interval is added to each symbol to overcome inter-OFDM symbol interference

Time

Frequency Band (divided into sub-carriers of 15KHz)

OFDMA Radio Frame and Data Structure

16


E-UTRAN Radio Frame Structure for FDD-LTE

17

0 1 2 3 4 5 6

7 OFDM Symbols

(short cyclic prefix)

1 Frame (10 msec)

1 Sub-Frame (1.0 msec)

1 Slot (0.5 msec)

0 1 2 3 10 11

19

0 1 2 3 4 5 6

cyclic prefixes

Cyclic Prefix is added before every symbol

LTE radio frame has fixed length of 10 ms . LTE radio frame is divided into 10 sub-frame (1 ms each)

Each sub-frame is further divided into two slots of .5 ms each

Each OFDM symbol carry either user or control information.

Different modulation techniques is used to send information in each symbol

Cyclic Prefix is precede each of symbol so that inter-channel interference is reduced

FDD is paired band for downlink and uplink


E-UTRAN Radio Frame Structure for TD-LTE

18

LTE radio frame has fixed length of 10 ms LTE radio frame is further divided into two half-frames of 5 ms each Each half-frame is divided into 5 sub-frames of 1 ms each

Two special sub-frames for signaling, Eight ordinary sub-frames for data Data sub-frame is further divided into slot of .5 ms each Symbols are put inside each sub-frame to carry user information Downlink and Uplink resources blocks are configurable


EUTRAN interface is very spectral efficient

Downlink: Orthogonal Frequency Division Multiple Access (OFDMA) in downlink

Uplink: Single Carrier – Frequency Division Multiple Access. Sub-carrier are still orthogonal

Variable modulations (QAM, 16 and 64 QAM)

Multiple Input Multiple Output (MIMO) technology to boot signal or send more bits

E-UTRAN Air Interface Overview

19


User measure quality in the downlink and signals to eNodeB in the Channel Quality Indicator (CQI).

The eNodeB decides which modulation technique to use based on the quality of the UL/DL radio

64 Quadrature Amplitude Modulation uses 2^6 = 64 combinations to carry 6 bits per symbol

16 Quadrature Amplitude Modulation uses 2^4 = 16 combinations to carry 4 bits per symbol

Quadrature Phase Shift Keying (QPSK) uses 2^2=4 combinations to carry 2 bits per symbol.

E-UTRAN Adaptive Modulations

20


Channel structures and mapping Logical channels define the type of information to be carried (control or user data) Transport channels define how information is transported (mapping to shared channels) Physical channels – mapping to DL or UP physical resources (bits, symbols, modulation, radio

frames etc.) carry the transport channel data across the air interface. Information is carried in shared channel. Unlike 3G there are no dedicated channels in LTE

Scheduling is most important - eNodeB manage DL and UL scheduling

E-UTRAN Channel Structures

21


LTE UE Categories & Challenges

22

Ability to support wide LTE spectrum- 700 MHz to 2600 MHz

Supporting inter-radio access handovers (2G, 3G, WiFi)

Supporting dual stack capability

MIMO and Amplifiers capabilities

Circuit Switched Fall Back (CSFB) support for voice calls through 3G

Voice support using VoLTE

Widely deployed


Number of states for UE (RRC states) are reduced from five to three

UTRAN (DETACHED, IDLE, URA_PCH, CELL_FACH, CELL_DCH)

EUTRAN (DETACHED, IDLE and CONNECTED)

UTRAN has two additional states CELL_FACH and CELL-PCH to optimize signaling

UMTS LTE GSM

Comparing GSM, UMTS and LTE Air Interface

23


E-UTRAN Design Summary

24

Deciding spectrum (700 – 2690 MHz) and band size (1.4 to 20 MHz)

LTE RF Design Overview

Link budget Calculations – Dense urban, urban, rural cell radius

Deciding LTE subscriber and services plan – Peak and average DL, UL

Calculating LTE coverage sites – Overlay 3G coverage

Adding capacity sites to meet subscriber bandwidth requirements

Factoring macro vs offload traffic

Number of subs per eNodeB – Total and attached, active

Ratio of uplink to downlink traffic





LTE E-UTRAN



DNS and NAT

LTE QoS and Policy





Agenda


25


eNodeB Traffic towards Mobile Backhaul

26

Operator’s

IP Services

Note: Refer to TS 36.300 and TS 23.401 for further details

UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

3GPP Access

E-UTRAN

PDN

Gateway

Serving

Gateway

PCRF

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted

Non-3GPP

IP Access

Untrusted

Non-3GPP

IP Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

eNodeB

UE

UE

SWu (IKEv2,

MOBIKE, IPSec)

• RRC Management. Layer-2 bridge between UE and EPC • Inter-eNodeB handover using X2 interface • IP header compression & Encryption of user data stream • MME selection at UE attachment and update • Routing of User Plane data towards SGW • Routing of Control Plane data towards MME • UL bearer level rate enforcement based on AMBR and MBR • UL and DL bearer level admission control • UL Transport level packet marking (EPS bearer QCI => DSCP) • Scheduling and transmission of paging messages (from MME) and broadcast information (from MME or O&M) • Measurement and reporting mobility and scheduling


X-2 user & control: ~ 3-5% (Applies only to Meantime Avg.)

Data 1 2 3 4

OA&M, Sync: <1% covering S1-MME, OAM etc. (% of overall traffic)

Transport GTP /Mobile IP Tunnel: ~10% (based upon packet size)

IPSec: Overhead of ~14%. (Based upon packet size)

Radio Data

Transport Overhead

Total bandwidth required at eNodeB Cell peak rate

Mobile Backhaul Last Mile – Factoring Overhead (1)

27


Protocol Overhead Octets

UDP Header 8

IP header 20 x 2 (1)

IPSec header 30

Total UDP 78

Ethernet overhead (802.1Q

excluding preamble)

22

Total 100

Payload (max) 1422

Average packet Size (2) 700

Overhead (700+100)/700 1.14

Transmission efficiency (3) 90%

Total overhead factoring

efficiency (1.14/90%)

1.26

Protocol Overhead Octets

UDP Header 8

IP header 20 x 2 (1)

IPSec header 0

Total UDP 48

Ethernet overhead (802.1Q

excluding preamble)

22

Total 70

Payload (max) 1452

Average packet Size (2) 700

Overhead (700+70)/700 1.10

Transmission efficiency (3) 90%

Total overhead factoring

efficiency (1.10/90%)

1.22

(1) Duplicated for packet fragmented by transport but not reassembled before arriving at eNodeB (2) Averaged packet size depend upon user Apps and can be obtained from existing network or research (3) Transmission efficiency factor fragmentation, other errors etc.

Mobile Backhaul Last Mile – Factoring Overhead (2)

28

With IPSec Without IPSec


Spectral

Efficiencybps/Hz

Bandwidth, Hz

64QAM

16QAM

QPSK

cell

average

Busy TimeMore averaging

UE1

UE2

UE3 : : :

Many

UEs

Quiet TimeMore variation

UE1

64QAMCell average

UE1

bps/Hz

QPSKCell average

UE1

bps/Hz

Hz Hz

a) Many UEs / cell b) One UE with a good link c) One UE, weak link

BW is designed on per cell/sector, including each radio type Busy time – averaged across all users Quiet Time – one/two users (Utilize Peak bandwidth)

For multi-technology radio- sum of BW for each technology (2G/3G/LTE) Last mile bandwidth- Planned with Peak ( radio) Factor overhead in last mile

Mobile Backhaul Bandwidth – Factoring Multi-Radios

29


Access Ring uWave/ Fiber

Agg-1 Ring

MME/SGW/PGW Apps (Bearer)

National Datacenter

HSS / PCRF/Billing Apps (control)

AGG-1 AGG-2 AGG-3

CSN

IP Backhaul Radio

Agg-2 Ring

Regional Datacenter

Peak rate Over subscribed (2 to 3) (based upon design, Redundancy, hierarchy)

Over subscribed ( 1 to 2) (based upon hierarchy)

Mobile Backhaul Bandwidth - Factoring Over

Subscriptions

30


Mean Peak overhead 4% overhead 10% overhead 25%

(as load->

infinity)

(lowest

load)

busy time

mean peak

busy time

mean peak

busy time

mean peak

busy time

mean peak

DL 1: 2x2, 10 MHz, cat2 (50 Mbps) 10.5 37.8 31.5 37.8 1.3 0 36.0 41.6 41.0 47.3

DL 2: 2x2, 10 MHz, cat3 (100 Mbps) 11.0 58.5 33.0 58.5 1.3 0 37.8 64.4 42.9 73.2

DL 3: 2x2, 20 MHz, cat3 (100 Mbps) 20.5 95.7 61.5 95.7 2.5 0 70.4 105.3 80.0 119.6

DL 4: 2x2, 20 MHz, cat4 (150 Mbps) 21.0 117.7 63.0 117.7 2.5 0 72.1 129.5 81.9 147.1

DL 5: 4x2, 20 MHz, cat4 (150 Mbps) 25.0 123.1 75.0 123.1 3.0 0 85.8 135.4 97.5 153.9

UL 1: 1x2, 10 MHz, cat3 (50 Mbps) 8.0 20.8 24.0 20.8 1.0 0 27.5 22.8 31.2 26.0

UL 2: 1x2, 20 MHz, cat3 (50 Mbps) 15.0 38.2 45.0 38.2 1.8 0 51.5 42.0 58.5 47.7

UL 3: 1x2, 20 MHz, cat5 (75 Mbps) 16.0 47.8 48.0 47.8 1.9 0 54.9 52.5 62.4 59.7

UL 4: 1x2, 20 MHz, cat3 (50

Mbps)*14.0 46.9 42.0 46.9 1.7 0 48.0 51.6 54.6 58.6

UL 5: 1x4, 20 MHz, cat3 (50 Mbps) 26.0 46.2 78.0 46.2 3.1 0 89.2 50.8 101.4 57.8

Scenario, from TUDR studyTri-cell Tput

Total U-plane + Transport overhead

No IPsec IPsecX2 OverheadSingle Cell Single base station

All values in Mbps

Use quiet time peak for each cell Not all cells will peak at same time- Factor this for 3 sector eNodeB Number of eNodeB in access ring - Number of hops, total bandwidth Access ring will have dual homing to pre-agg

Total BW = DL + UL (20MHz, 2X2 DL MIMO, 1X2 UL MIMO) 105.3+42 ~ 145 Mbps

* Ref – Next generation Mobile Network (NGMN) backhaul planning document

Mobile Backhaul Bandwidth Table*

31


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5 6 7 8 9 10

Gbps

Tricell eNodeBs

5: 4x2, 20 MHz, cat4 (150 Mbps)no IPsec





0.01

0.1

1

10

100

1000

1 10 100 1000 10000

Gbps

Tricell eNodeBs

single cell eNodeBs:

1 2 3 6 9 12 15 18 21 24 27 30

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5 6 7 8 9 10

Gbps

Tricell eNodeBs

5: 1x4, 20 MHz, cat3 (50 Mbps) no IPsec

4: 1x2, 20 MHz, cat3 (50 Mbps)*no IPsec




0.01

0.1

1

10

100

1000

1 10 100 1000 10000

Gbps

Tricell eNodeBs

single cell eNodeBs:

1 2 3 6 9 12 15 18 21 24 27 30

Do

wn

lin

k U

plin

k

Total BW = DL + UL ; For 10,000 eNB (Tricell) = 700+500 = 1200 Gbps (Per eNB in Core ~ 1200/10,000 ~ 120 Mbps) Over-subscription is not factored. Based upon over-subscription reduce bandwidth accordingly in Core

* Ref – Next generation Mobile Network (NGMN) backhaul planning document

Mobile Backhaul Bandwidth – Agg & Core*

32


UE trafficserved by eNodeBs

Last mile

serves eNodeBs

aggregationcore

eNodeBs

Transport

network

External

Networks

Mobile Backhaul – Access ring

Bandwidth- Full access capacity (Peak rate)

Resiliency, failover, dual homing

Routing - L2/L3 based on requirements.

L3 is recommended

Core/Super backbone

Bandwidth - mean average with over subscription

Connecting backhaul from all regions

Regional and National Datacenter

Internet, roaming partners, Applications

Routing – MPLS VPN/Global routing

Mobile Backhaul – Pre-agg/Agg

Bandwidth- mean average with oversubscription

Aggregating access and pre-agg rings

Agile & resilient architecture to backhaul BW

Routing- L2/L3VPN, Any-to-any routing

Mobile Backhaul Routing Strategy

33


Traffic Types Characteristics Design Strategy

1 S1-MME Control plane, security, high latency will affect

Mobility Management.

Separate VLAN or VPN towards MME

2 S1-U User plane, sensitive to delay, packet loss.

Different QoS requirements

Separate VLAN or VPN towards SGW

3 eMBMS Multicast control and user traffic Routed through 1st layer-3 hop

4 X2 Layer-3 X2 handover traffic Routed through Pre-agg/Agg

5 Clock Clock and synchronization, Delay sensitive Normally global routed towards Grand

Master

6 O&AM eNodeB OAM traffic Separate VLAN/VRF

Based upon radio vendor different types of traffic combined into few VLAN’s Mobile backhaul design should support further segregation of traffic Implement transport QoS to ensure proper routing of traffic

eNodeB Traffic and Routing Strategy

34





LTE E-UTRAN



DNS and NAT

LTE QoS and Policy





Agenda


35


LTE standards have strict design requirements for latency

Control < 100 ms (idle to active)

User <5 ms (one way UE to RAN edge). Network latency is additional

LTE Latency is broadly divided into

E-UTRAN latency (UE to eNodeB)

Network latency (eNodeB to core network)

E-UTRAN latency depend upon

Radio quality, resources (capacity) and UE category

Network Latency depend upon

Processing delay – depend on CPU, memory and load

Serialization delay- depend on packet size and interface speed

Queuing delay – depend upon packets in queue & serialization

Propagation delay – Depend on distance and media

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00800a8993.shtml

Latency Considerations for LTE Design

36

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00800a8993.shtml


Throughput vs. Latency *

Throughput at applications layer depend many factors such as Radio conditions – More throughput near cell compared to edge Latency - Increased latency reduces overall throughput Packet loss - Lead to re-transmissions and less throughput at application layer Packet size - Larger packer size has better throughput

http://www.silver-peak.com/calculator/ * LSTi and other published references

37

http://www.silver-peak.com/calculator/




Camped-state (idle)

Active (Cell_DCH)

Dormant (Cell_PCH)

Less than 100msec

Less than 50msec

C-Plane Latency (ref TR25.913, V8.0.0) C-Plane Latency (ref TR36.913, V9.0.0)

Camped - state

Active (in-sync)

Active – “dormant” (un-sync)

Less than 50 ms

Less than 10 ms

Idle to active < 100 ms when user plane is established Dormant to Active <50 ms

Idle to active <50 ms when user plane is established Dormant to Active <10 ms

Control Plane (C-Plane) – Relates to completion of E-UTRAN and NAS signaling

User Plan (U-Plane) – Relates to establishment of bearer path

For your reference Control Plan Latency Requirements

38


User Plane Latency- (3GPP TS25.912)

User plane Latency Refers to Establishment of Bearer Path to SGW

Description Duration

LTE_IDLELTE_ACTIVE delay (C-plane establishment) 47.5ms + 2 * Ts1c

TTI for UL DATA PACKET 1ms

HARQ Retransmission (@ 30%) 0.3 * 5ms

eNB Processing Delay (Uu –> S1-U) 1ms

U-plane establishment delay (RAN edge node) 51ms + 2 * Ts1c

S1-U Transfer delay Ts1u (1ms ~ 15ms)

UPE Processing delay (including context retrieval) 10ms

U-plane establishment delay (Serving GW) 61ms + 2 * Ts1c + Ts1u

Ts1c = 2ms – 15 ms Ts1u = 1ms – 15 ms

For your reference

39


Distributed MME+SGSN

+GGSN +SGW+PGW


+GGSN +SGW+PGW



Centralized SGW+PGW

+GGSN


+GGSN SGW+PGW

IP Backbone

LTE

2.5G

3G

Centralized SGSN+GGSN

MME+SGW+PGW

IP Backbone

LTE

2.5G

3G

IP Backbone

LTE

2.5G

3G

Distributed SGW+PGW+GGSN

Distributed SGW+PGW+GGSN

Centralized MME+SGSN IP Backbone

LTE

2.5G

3G

Why combo and which nodes to combine?

Optimizing Mobile Gateway Design

40


Gateway Placements Considerations Entity Placement Considerations

MME Moderate distribution

Latency <50ms from eNB to MME (S1-MME),

Faster signaling/call setup

Use MME pooling - scaling & geographical redundancy

SGW/PGW Distributed, close to edge

Latency <50 ms from eNB (S1-U), better user experience

Co-locate/Co-host SGW/PGW if design permit

HSS Centralized/Moderate distribution

Latency <100 ms. Latency impact default bearer set-up

Partition HSS as front end and backend if design permit

Front-end co-locate with MME if possible

Database

SPR

Centralized

Latency <100 ms. Latency impact database query, sync

Replicate database at multiple locations

Co-locate with HSS backend

SPR Subscriber Profile Repository , Database Entity

41


Gateway Placements Considerations

Entity Placement Considerations

PCRF,

Balance

Manager,

OCS/OFCS

Centralized

Latency <100 ms. Latency impact policy download, updates

Can share database with HSS

Balance Manager, Online Charging co-located with PCRF

DNS Tracking Area/APN DNS – Used by MME, co-locate with MME

Mobile DNS – Used by UE, distributed. Co-located with PGW

Internet DNS – Used for inbound query, Centralized

Roam DNS – Used by roaming partners, Centralized

Infrastructure DNS – Used by internal infrastructures, Centralized

AAA Centralized

Used for ePDG (3GPP) – centralized

Infra. device authentication - centralized

DHCP Centralized

DHCPv6 for IP address allocation

OCS – Online Charging system, OFCS – Offline Charging System

42


Mobility Management Entity (MME)

43

Operator’s

IP Services


CN Core Network eNBs eNodeBs HSS Home Subscriber Server MME Mobility Management Entity NAS Non Access Stratum SGSN Serving GPRS Support Node

UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

E-UTRAN

PDN

Gateway

Serving

Gateway eNodeB

PCRF

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted

Non-3GPP

IP Access

Untrusted

Non-3GPP

IP Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

UE

UE

MME

SWu (IKEv2,

MOBIKE, IPSec)

• Signalling anchor point for eNodeB and UE • NAS signalling (control plane signalling to the UE) • NAS signalling security (ciphering and integrity protection) • PGW and SGW selection during bearer establishment • SGSN selection for handovers to 2G/3G using S3 • Bearer management including dedicated bearer establishment • Tracking Area list management for UE • Paging management (Intelligent paging) • MME pooling to reduce signalling, increase availability • Inter-MME handover using S10 interface • Support roaming


MME Interfaces Design Considerations

S1-MME (Towards eNodeB) Number of eNodeB SCTP Multihoming MME Pooling TAI list management

S6a (Towards HSS) Number of HSS and frontends Logic for HSS selection SCTP multihoming

S13 (Toward EIR) Co-located with HSS EIR supports DIAMETER interface?

DNS Logic for gateway selection – priority, weight, collocation etc. Fall back logic for gateway selection

S11 (Towards SGW)

DSCP Marking Security Gateway

DSCP Marking

LI 44


MME Pooling Strategy

Region B

MME POOL

MME A

MME C

Region A

MME B

Region C

eNodeB has multiple active S1-MME links to MME’s in pool

Number of MME’s clustered in pool across geographical area MME in pool is identified by Code & Group Identifier All MME in pool will have same Group identifier eNodeB decide MME based upon weight, load etc.

45


Benefits of MME Pooling

Enables geographical redundancy, as a pool can be distributed across sites

Increases overall capacity, as load sharing across the pool

Converts inter-MME Tracking Area Updates (TAUs) to intra-MME TAUs for moves between the MMEs of the same pool.

Reduces signaling load & transfer delay

Easy introduction of new MME in pool.

Eliminates single point of failure for eNodeB and MME.

Increase MME availability

46


LTE UE Mobility Management

Three main states for mobility - IDLE, ACTIVE,DETACHED

LTE_IDLE: State is power-conservation (No Tx and Rx from UE) No context about the UE is stored in the eNB. Location of the UE is only known in MME MME knows only last Tracking Area (TA) before UE went idle Tracking Area usually consist of multiple eNodeB MME will page the UE if SGW has network initiated data for UE

LTE_ACTIVE: UE has RRC connection with the eNodeB UE is registered with the MME UE has default PDN with PGW MME knows the UE (Tracking Area which includes eNodeB) UE can transmit/ receive data

LTE_DETACHED: Transitory sate during UE power ON UE is searching to register to network

47


LTE UE Mobility - Idle and Connected Mode

LTE_IDLE Mode Mobility UE can move from one eNodeB to another eNodeB is unaware of UE MME know the last state based upon tracking area

information (TAI) Idle mode mobility is controlled by MME

LTE_ACTIVE Mode Mobility UE has RRC to eNodeB. UE send measurement information Source eNodeB initiate X2 handover if X2 link is up Source eNodeB initiate MME controlled handover eNodeB buffer data during handover

48


MME Heuristic Paging

To limit the volume of unnecessary paging related signaling

MME maintains a list of “n” last heard from eNB‘s inside the TAI for the UE

MME uses Tracking Area Updates to build this local table

For incoming page request for the idle mode user, the MME attempts to page the user at the last heard from eNB

If no response then MME will page last n heard eNB

If still no response then page all eNB in TAI

49


MME Design Parameters

MME parameters Per sub/Hr

1 Initial UE Attach/Detach

2 Bearer activation/deactivation per PDN session

3 PDN connection setup/tear down

4 Ingress and Egress paging

5 Number of eNodeB

6 Idle-active/active-idle transactions

7 Number of bearer per PDN session

8 Number of PDN sessions

9 Intra-MME S1 handover with SGW relocation

10 Intra-MME S1 handover without SGW relocation

11 Intra-MME X2 handover

12 Inter-MME handover

13 Intra-MME tracking area updates

14 Inter-MME tracking area updates

For your reference

50


Serving Gateway (SGW)

51

Operator’s

IP Services

Note: Refer to TS 23.401 for further details

• One SGW at a time per UE • Anchor point for inter- eNodeB handover if no X2 interface • Mobility anchoring for inter-3GPP mobility (terminating S4 and relaying traffic between 2G/3G system and PGW) • Packet buffering during handover, normal routing and forwarding • Uplink and Downlink transport level packet marking (DSCP) •Lawful Interception • Accounting ;user and QCI granularity for inter-operator charging • Uplink and Downlink charging per UE, PDN, and QCI • ECM-IDLE mode downlink packet buffering and initiation of network triggered service request procedure (towards MME)

QCI QoS Class Identifier

PDN Packet Data Network

UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

E-UTRAN

PDN

Gateway eNodeB

PCRF

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted

Non-3GPP

IP Access

Untrusted

Non-3GPP

IP Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

UE

UE

Serving

Gateway

SWu (IKEv2,

MOBIKE, IPSec)


SGW Interfaces Design Considerations

52

S1-U (Towards eNodeB) DSCP marking Security Gateway

S11 (Towards MME) Control signaling messages DSCP marking

S5/S8 (Towards PGW) Control and bearer tunnels towards PGW DSCP marking

Optional CDRs

LI


PDN Gateway (PGW)

53


AMBR Aggregate Maximum Bit Rate

DPI Deep Packet Inspection

MBR Maximum Bit Rate

Non-GBR Non Guaranteed Bit Rate

PDN Packet Data Network

RAT Radio Access Technology

• Provide UE IP address allocation (IPv4, IPv6, IPv4/v6 both)

• De-encapsulation GTP to IP traffic. Connectivity to IP services • DHCPv4 and DHCPv6 functions (client, relay and server) • UE can connect to more than one PGW • Deep Packet and Deep Flow inspection, differentiated billing • Lawful Interception • Uplink and Downlink transport level packet marking (DSCP) • Downlink rate enforcement based on AMBR (e.g. for all Non-GBR) • Downlink rate enforcement based on MBR of same QoS • Optional Pre-rel 8 SGSN interface Gn/Gp UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

E-UTRAN

Serving

Gateway eNodeB

PCRF

Operator’s

IP Services

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted Non-

3GPP IP

Access

Untrusted

Non-3GPP

IP Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

UE

UE

PDN

Gateway

SWu (IKEv2,

MOBIKE, IPSec)


PGW Interfaces Design Considerations

54

Gx (Towards PCRF) Traffic based upon use cases, volume reporting SCTP multihoming

Gy (Towards pre-paid platforms) SCTP multihoming Pre-paid quota management and billing

S5/S8 (Towards SGW) Control and user tunnels, DSCP marking

AAA (For authentication, authorization) Requirement for AAA accounting Delayed sending of Create-Session-Response

Lawful intercept (LI)

S12 - Direct Tunnel For 3G RNC direct tunnel

SGi (Towards PCEF / IP Services) De-encapsulated IP traffic


PGW General Design Considerations

55

CDRs Fields required in CDR File format Onboard storage, external CGF

Deep packet Inspections Support for enhanced charging Dimensioning depend upon number of charging rules

IP Addressing IPv4, IPv4IPv6? Address allocation – DHCP, AAA, local pool? Requirement for NATing on PGW Inter-mobile traffic

APN Consumer only or corporate Defining virtual APNs

Bearers Max number of default bearers – Max PDNs Max number of dedicated bearers – Max differentiated services


SGW/PGW Design Parameters

1 Number of Simultaneous active subs

2 Number of subs using IPv4 (% IPv4 PDN)

3 Number of subs using IPv6 (% IPv6 PDN)

4 Number of subs using IPv4v6 (% IPv4v6 PDN)

5 Number of bearer activation/deactivation per PDN/Hr

6 Number of average bearer per PDN connection

7 Number of PDN connection setup/tear down per sub/Hr

8 Number of PDN session per sub

9 Number of idle-active/active-idle transaction per sub/Hr

10 Number of intra SGW handover per sub/Hr

11 Number of Inter SGW handover per sub/Hr

12 Number of inter-system handover per sub/Hr

SGW/PGW Design Parameters For your reference

56


SGW/PGW Design Parameters

PCEF (Policy Control Enforcement Function) Design

1 No of flow /subscriber

2 % of deep flow inspection

3 % of deep packet inspection

4 % of PDN connection using Gy (pre-paid)

5 % of PDN connection using Gx (Policy interface)

6 Number of Gx Transactions per PDN Connection/Hr

6 Number of Dynamic Rules

Data Subs Traffic

1 % of subs simultaneously sending/receiving data

2 Average packet size for DL

3 Average packet size for UL

SGW/PGW Design Parameters (Cont’d) For your reference

57


Transport Traffic- Bearer setup for dual stack UE

3GPP Rel-8 onward

Dual stack User send one PDP request “IPv4v6”

Gateway will create bearer; Allocate IPv4 & IPv6 to same bearer

For GPRS network single bearer is applicable from 3GPP Rel-9 onward

Prior to 3GPP Rel-8 (LTE introduced from Rel-8 onward)

Dual-stack User sends two PDP requests- One of for IPv4 and another for IPv6

Gateway creates two unique PDP-contexts- One for IPv4 and another for IPv6.

Dual stack

Dual stack

58


Typical User Plane IPv6 Configuration

3GPP R8 UE requested PDN types?

1. IPv4v6 (default)

2. IPv4

3. IPv6

HSS

Compare Requested PDN

type with user subscribed?

PGW

APN provisioned with

1. IPv4, IPv6, IPv4 and IPv6

2. Local, AAA, DHCPv6?

59


Bearer Setup Procedure for IPv6

60

Create Session Request (APN, QoS,

PDN-type=IPv4v6…)

Create Session Request (APN, QoS,

PDN-type=IPv4v6,…)

Create Session Reply (UE Prefix,

Protocol config options (e.g. DNS-server list,…),

cause)

Create Session Reply (UE Prefix,

Protocol config options, cause)

AAA DHCP PGW SGW MME

Attach Request

Attach Accept

Router Solicitation

Router Advertisement

UE

DHCPv6 – Information Request

DHCPv6 PD Option 3

DHCPv6 – Confirm

DHCPv6 – Relay Forward

DHCPv6 – confirm

DHCPv6 – Reply forward DHCPv6 – Relay Reply

Prefix Retrieval Option 2

Option 1 /64 prefix allocation from local pool

SLAAC

Prefix communicated to SGW/MME

empty UE IP-address for dynamic allocation

/64 prefix allocation: 3 Options: Local Pool, AAA, DHCP

UE ignore IPv6 prefix

received in attach

HSS compare requested PDP types (IPv4,

IPv6, IPv4v6) with subscribed. Provide list of

subscriber APN with PDN type

RA contain the same IPv6 prefix as the

one provided during default bearer

establishment UE request additional

information in DHCPv6


IPv6 Subnet Considerations for Infrastructure

Interface ID

/32 /64 /16

128 Bits

/48

Regions (/40 256 regions)

Functions within region (/48 provides 256 functions) (eNodeB, IP-BH, MPLS Core, MME, HSS, SGW, PGW, Datacenter, Security etc.)

Devices and subnets for each devices (48 – 64 provides 65,000 subnet of /64)

Infrastructure subnets are typically not announced to internet

Use proper summarization to optimize routing scalability

Point-to-point Interface address: Choices - /127, /64

Loopback /128

Subnetting Example (Assuming - /32 for Infrastructure)

61


IPv6 Subnet Considerations for Subscribers

Interface ID

/32 /64 /16

128 Bits

/48

Regions (/40 256 regions)

Services/APN within region (/48 provides 256 ) (IMS, Internet, Video, M2M, Message, Enterprise etc.)

Devices and subnets for each devices ** (48 – 64 provides 65K users within each service/APN)

LTE Users IPv6 subnets are announced to internet

Separate block for each service i.e. APN/virtual APN

Allocation strategy – Local Pool, AAA, DHCPv6

Subnet strategy – Ability to identify services, easy growth

Subnetting Example (Assuming /32 for LTE Users)

** For wireless routers gateway allocated smaller block i.e. /60, /56 or /48 etc.

62





LTE E-UTRAN



DNS and NAT

LTE QoS and Policy





Agenda


63


DNS Design

DNS Functional description

Tracking Area/APN

DNS

Initial Attach

•MME perform APN query to find PGW, MME perform track Area query to find SGW

Handover with TAI change & Tracking Area Updates

•MME perform track query to determine SGW

•MME select closest SGW to PGW send create session request

Mobile DNS •LTE UE query mobile DNS to resolve “Host Name” to IP address

•Can be DNS64 (LTE UE with IPv6), DNS44 (LTE UE with IPv4)

Internet DNS •Mainly root DNS. Need DNS64 capability

Infrastructure DNS •Name resolution in the OAM (e.g. admin to login to the device, SNMP)

Roam DNS •Used for roaming traffic. Need IPv6 capability of roaming transport is IPv6

E-UTRAN PDN

Gateway Serving Gateway

eNodeB

PCRF

Operator’s IP Services

HSS

Gxc (Gx+)

S11 (GTP-C)

S1-U (GTP-U)

MME

S6a (DIAMETER)

S1-MME (S1-AP)

S5 (GTP-C,GTP-U)

Gx (Gx+)

SWx (DIAMETER)

3GPP AAA S6b

(DIAMETER)

SGi

Rx+

UE

Tracking Area/APN DNS

Mobile DNS S10 (GTP-C

Infrastructure DNS Internet DNS

Roam DNS

64


Large Scale NAT -Where to Place the NAT Function?

65

PGW & NAT44/64

eNB

IPv4

private IPv4

IPv4 Public

public IPv4

SGW

NAT44/64

PGW eNB

IPv4 IPv4

private IPv4 private IPv4

IPv4 Public

public IPv4

CGN/ CGv6

SGW

NAT

NAT44/64

NAT

Option 1: NAT on Mobile Gateway (Distributed)

Option 2: NAT on Router (Centralized)

Key Benefits:

• Subscriber aware NAT

- per subscriber control

- per subscriber accounting

• Localized IPv4 pool mgmt

• Highly available

(incl. geo-redundancy)

Key Benefits:

• Integrated NAT for multiple

administrative domains

(operational separation)

• Large Scale

• Overlapping private IPv4

domains (e.g. w/ VPNs)

• Intelligent routing to LSN





LTE E-UTRAN



DNS and NAT

LTE QoS and Policy





Agenda


66


QCI

Value

Resource

Type

Priority Delay

Budget (1)

Error Loss

Rate (2)

Example Services

1 (3) 2 100 ms 10-2 Conversational Voice

2 (3)

GBR

4 150 ms 10-3 Conversational Video (Live Streaming)

3 (3) 3 50 ms 10-3 Real Time Gaming

4 (3) 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming)

5 (3) 1 100 ms 10-6 IMS Signalling

6 (4)

6

300 ms

10-6

Video (Buffered Streaming)

TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing,

progressive video, etc.)

7 (3) Non-GBR 7 100 ms

10-3

Voice, Video (Live Streaming), Interactive Gaming

8 (5)

8

300 ms

10-6

Video (Buffered Streaming)

TCP-based (e.g., www, e-mail, chat, ftp, p2p sharing,

progressive download, etc.)

9 (6) 9

LTE Application QoS Requirements (3GPP TR23.401 V8.1.0 )

67


Agg-1 Agg-3 Agg-2

S1-U, S1-C, X2

Agg-3

UE

MME

S1-C, S-10

S-11, Gn

Cell site router

P-GW

S-GW

S1-U, S-11, Gn

Regional Datacenter

Main Datacenter

Marks traffic with appropriate DSCP (QCI) values

Traffic shaping / queuing / prioritization

Hierarchical Traffic shaping with policy maps

Maps DSCP values to MPLS EXP

Traffic reclassification

eNB

LTE Transport QoS Requirements (1)

Making sure that packet marked at eNodeB, SGW, PGW (QCI to DSCP) is carried through transport without altering DSCP markings and QoS characteristics

68


LTE Transport QoS Requirements (2)

DSCP – differentiated services Code Points

User level QoS is obtained from PCRF

User level QoS needs to enforced at transport level

QCI to DSCP mapping in eNodeB, SGW, PGW provide marking of different traffic

QoS enforcement – classification, queuing is applied consistently across all transport elements

Application dataTCP HeaderEthernet Header Ethernet Trailer

Ethernet frame

IP Header

version(4 bits)

header length

Type of Service/TOS(8 bits)

Total Length (in bytes) (16 bits)

Identification (16 bits)flags

(3 bits)Fragment Offset (13 bits)

Source IP address (32 bits)

Destination IP address (32 bits)

TTL Time-to-Live(8 bits)

Protocol(8 bits)

Header Checksum (16 bits)

32 bits

69


Hierarchical QoS Deployment in Mobile Transport Hierarchical QoS is a queuing framework that allows for multiple levels of

queue and different treatments for each queue

In the example below 1 Gbps can be divided into four logical link of 200 Mbps each. Separate queuing mechanism can be applied to logical link.

70


3GPP Policy Control Architecture (PCC) General PCC Principles

Traffic classifed as Service Data Flows

Charging and QoS control, Gate control at PCEF

QoS policies propagated to the mobile edge

Push and Pull models

Session update notification

Diameter based interface (Gx, Rx, Gy)

3G PCEF

Use for enforcing policy

Co-located with PGW and SGW

Subscriber Profile repository (SPR)

Database used to store per user policy rules

Integrated with main HSS

Integrated with Top-up server (For pre-paid subs)

OCS and OFCS

Online Charging (OCS) for pre-paid subscriber billing

Offline Charging (OFCS) for post-paid subscriber billing

Mobile Gateway (inc. PCEF)

PCRF

OCS OFCS

Gx

Rx

Sp

SPR

Gy Gz

Applications

71

http://www.nortel.com/





LTE E-UTRAN



DNS and NAT

LTE QoS and Policy





Agenda


72


LTE Interworking with 3G/2G

SGi

GERAN

UTRAN

S11

S3

S5/S8

HSS

S4

S1-U

S1-MME

S6a

SGSN

IP Network

Gx

X2

PCRF

Serving Gateway

S12

PDN Gateway

Standards based interfaces for

inter-working with other 3GPP &

non-3GPP networks

MME

MME, S-GW & PDN-GW are

logically defined functions

New interface / direct

connectivity now exists

between eNB’s

eNB

eNB

E-UTRAN UE

MME – Mobility Management Entity

HSS – Home Subscriber Server

PCRF - Policy and Charging Rule Function

73


LTE Deployment Choices

74

Inter-working directly

with legacy network

Inter-working with

legacy core upgraded to R8

“ 4G ” RAN 3G RAN

eNB eNB

S - GW S - GW

MME MME

HLR HLR

S1 - MME

S11

S1 - U

P - GW P - GW

S5,S8

SGi

S6a

S10

SGSN SGSN SGSN

X2

RNC RNC RNC

Gr

GGSN GGSN GGSN

Gn

Gi

HSS HSS

PDN

Iu - PS

backhaul

backbone

NodeB NodeB NodeB

GTP v2

IuB

3G and LTE working in

separate gateways


LTE Roaming - Infrastructures IP Exchange (IPX) 1. IP Exchange (IPX) is next-gen innovations for UMTS/LTE data roaming 2. Any-to-any roaming architecture

1. IPX combines roaming between large ecosystem service providers (mobile, fixed, ISP, Application Service Providers etc.)

2. End-to-end QoS for roaming and interworking 3. Any IP services on a bilateral basis with end-to-end QoS and interconnect charging 4. IPX-proxy provide service-interworking, intelligent routing at Application layer **

3. IPX charging – Enhanced service aware billing – volume, type, discounts etc.

Service Provider-1

Service Provider-2

Service Network-3

IPX Service Provider-1

IPX Service Provider-2

DNS root database, ENUM

IPX Proxy IPX Proxy

End-to-end SLA

75


LTE Roaming – Home Routed

76

Mobile register in visited network radio

eNodeB send attach request to visited MME

Visited MME forward attach request to home HSS using S6a interface

UE is authenticated from Home HSS

Visited MME perform node selection - SGW and PGW

For home routed traffic, visited SGW will forward entire traffic, all APN to home PGW

Diameter interfaces inter-PLMN: S6a, S9

LTE roaming is new and very few case studies

Deployed by majority of LTE operators

S6a

HSS

S8

S3

S1 - MME

S10

UTRAN

GERAN

SGSN

MME

S11

Serving

Gateway UE

“ LTE

- Uu

”

E - UTRAN

S12

HPLMN

VPLMN

PCRF

Gx Rx

SGi Operator’s IP

Services

PDN

Gateway

S 1 - U

S4

Home-Routed

From TS 23.401


LTE Roaming – Selective Local Breakout (Ref TS 23.401)

Mobile register in visited network radio. eNodeB send attach request to visited MME


UE is authenticated from Home HSS. Visited MME perform node selection - SGW

Visited MME select PGW based upon APN type

For default PDN MME select local PGW

Traffic for other PDN e.g. VoLTE, video, VPN, enterprise customer etc. routed to home PGW

Bulk of traffic is routed locally

S6a

HSS

S 5

S3 S1 - MME

S10

GERAN

UTRAN

S G SN

MME

S11

Serving G ateway UE

" LTE - Uu" E - UTRAN

S4

HPLMN

VPLMN

V - PCRF

Gx

SGi

PDN G ateway

S1 - U

H - PCRF

S9

Home Operator’s IP

Services

Rx

Visited Oper ator PDN

S12

Local Breakout default APN, other APN home routed

77


LTE Roaming – Local Breakout Everything (From TS 23.401)

Mobile register in visited network radio. eNodeB send attach request to visited MME


UE is authenticated from Home HSS. Visited MME perform node selection - SGW & PGW locally

All traffic is routed locally in visited network

Local Breakout for all services.

S6a

HSS

S3

S1-MME

S10

UTRAN

SGSN

MME

S11

Serving Gateway

S5

UE

LTE-Uu

E-UTRAN

S4

HPLMN

VPLMN

V-PCRF

Gx

SGi PDN

Gateway

S1-U

H-PCRF

S9

Visited Operator's IP

Services

Rx

GERAN

S12

78


Assess network readiness for LTE. This will help operationalizing LTE quickly

Radio planning – Spectrum, bandwidth, re-farming existing spectrum

Base station planning - Reuse existing UTRAN, new sites

Backhaul planning – major upgrade to IP/MPLS based backhaul

Assess & Develop IP Skill set. Skill gaps among RF, BTS & Core engrs reduced

Training staff in LTE, IMS, IP Routing etc.

Business Planning

Service plan, New Applications, New Subscribers

End-to-end LTE/EPS Design

Designing whole network aligning with business objectives

Radio, Transport, Gateways, Datacenter, Applications

LTE Deployment Strategies & Best Practices (1)

Prepare and Design

79


Market by market field trials with real users

Develop and customize LTE KPI, correlate KPI across multiple devices/vendors

Develop operations troubleshooting tools, process and guide

Integrate new infrastructures with existing NOC, OSS/BSS - Support structure

Monitor and optimize as necessary

Field Trials and Deployment

Lab integration and testing – vendors facility, SP facility

System level IOT- All vendors, All related elements, All Apps

I-RAT testing - 2G/3G; Offload – WiFi, Femto

Device ecosystem testing – Different devices and Apps testing

Roaming testing with other LTE, UMTS networks

Test and Validation LTE Deployment Strategies & Best Practices (2)

80


Summary

81

LTE Technology Needs Design, test & validation, Inter-operability testing and implement best practices Use open standards (3GPP, IETF, ITU,NGMN, LSTi ), extensive testing and right KPI’s Security – Infrastructure, Subscribers, Internet IP Skills to manage LTE Though LTE leverage existing 3G infrastructure, but significant changes in architecture Breaking boundaries between RF, backhaul, core engineering roles Thorough understanding of IP and tools e.g. using wireshark for RF troubleshooting LTE Deployments Stats (Ref: Infonetics Research, Inc 2012 2009 (2 networks), 2010 (15 networks), 2011: 29 networks 2012: 25 networks as of 5/08/12. Total projections of 144 LTE networks in 59 countries

GSA - Global mobile Suppliers Association (http://www.gsacom.com)

http://www.gsacom.com/

http://www.gsacom.com/


1. 3GPP http://www.3gpp.org (Standards)

2. Cisco SP Mobile community - https://communities.cisco.com/community/solutions/sp

3. Cisco Mobile Packet Core portfolio www.cisco.com/go/mobile

4. IP Design for Mobile Networks Cisco Press (By Mark Grayson, Kevin Shatzkamer, Scott Wainner)

5. LTE Security, Wiley (Author – Dan Forsberg and others)

6. NGMN http://www.ngmn.org (White paper on Gateways, backhaul, security)

7. 4G Americas http://www.4gamericas.org (Whitepapers)

8. ETSI Studies on latency requirements for M2M applications

http://docbox.etsi.org/Workshop/2010/201010_M2MWORKSHOP/

9. Global Certification Forum – Testing mobile devices

http://www.globalcertificationforum.org/WebSite/public/home_public.aspx

10. White paper on Latency Improvements in LTE

http://www.ericsson.com/hr/about/events/archieve/2007/mipro_2007/mipro_1137.pdf

http://www.techmahindra.com/Documents/WhitePaper/White_Paper_Latency_Analysis.pdf

11. NGMN publications on backhaul bandwidth planning, M2M etc

References

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