LTE Workshop

September 2015
LTE Workshop
Mohammad Hajizadeh
LTE Technical Manager
mr.hajizade@gmail.com

LTE Workshop
Agenda
 This is part of comprehensive workshop, include:
 Session 1: Introduction of LTE; Features & Objectives
 Session 2: Architecture & Components
 Session 3: Technical Aspects of LTE
 Session 4: LTE; Continual Evolution
 Session 5: New Services and Better Experiences

September 2015
Session 1:
Introduction of LTE; Features & Objectives

Standards availability

The Evolution of Mobile Technologies
Mobile 1G Mobile 2G Mobile 3G Mobile 4G

The Evolution of Mobile Technologies
 2G: GSM, Mainly voice, First Digital Standard, Add Packet Services: GPRS, EDGE
 3G: Designed for voice with some data consideration, First Mobile Broadband
 4G: Designed primarily for data, full IP-based protocols, true mobile broadband

Growing Mobile Data Traffic
● Mobile data traffic will grow 12 times by the end of 2018
LTE subscribers consume more & more data
Increased Device Capability
● Larger and higher quality screens
● More memory and processing capability
12×

LTE
New
Services
Video
Content
Data
Explosion

9.5 BILLION
Mobile subscriptions by
the end of 2020
~ 90%
Of mobile subscriptions will be for
mobile broadband by the end of 2020
6.1 BILLION
Smartphone subscriptions
by the end of 2020
Q4 2010:
traffic generated
for mobile data
is twice that
for voice
X2
55% growth
in data traffic
between Q4 2013
and Q4 2014
Total(uplink+downlink)monthlytraffic(PetaBytes)

Features
 All-IP Network → New all-IP mobile core network introduced with LTE
 Needs at the access level for LTE
 Key Features of LTE → Multiple access scheme, Adaptive modulation and coding, Bandwidth scalability,…
 3GPP LTE objectives → Spectrum efficiency, Capacity, Mobility

Frequency Bands
CoverageCapacity
Device
Availability
Regulation
Capex/Opex Geographical
status
Cost
Capacity
Coverage
Sub 1 GHz
1.8 GHz
2.6 GHz
Lower Higher

 312 Operators launched FDD mode only
 31 Operators launched TDD mode only
 17 Operators launched FDD & TDD modes
 = 360 commercially launched LTE networks
Frequency Bands
1
12
7 8 10 10
36
55
68
91
158
450 MHz 1900 MHz 850 MHz APT 700 900 MHz 2100 MHz AWS 700 MHz 800 MHz 2600 MHz 1800 MHz
No. of NetworkFrequencyBand
212.3 GHz40
122.6 GHz38
102.6 GHz41
93.5 GHz42
11.9 GHz39
Commercially launched LTE networks (Jan 2015)
TDD Networks

Device Availability

Primary motivation for LTE
6%
10%
15%
22%
18%
29%
to enter mobile data
market for the first
time
Modernizing legacy
radio network
architecture
build brand value
through technology
leadership
create new revenue
streams based on LTE
Reduce the cost of
mobile data
Current networks do
not offer sufficient
capacity

September 2015
Session 2:
Architecture & Components

Architecture & components
LTE Architecture
•External networks
•Operator Services
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

The E-UTRAN
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

eNodeB
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

eNodeB
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
•Mobility Management
•Bearer handling
•Security settings
•User plane tunnels for UL and
DL data delivery
•Inter eNodeB handovers
•Forwarding of DL data during handovers
•Radio Resource Management
•Mobility management
•Bearer handling
•User plane data delivery
•Securing and optimizing radio interface delivery

Evolved Packet Core (EPC)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

Evolved Packet Core (EPC)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRFS1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
S1-U
eNB

Mobility Management Entity (MME)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

Mobility Management Entity (MME)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
• Authentication and Security
•Location management
• User profiles
• Control of user plane tunnels
• Inter eNodeB handovers
• State transitions
• Bearer management
• Paging
• Handovers between MMEs
• Idle state mobility between MMEs
eNB
S1-U

Serving Gateway (SGW)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

Serving Gateway (SGW)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRFS1-MME
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
• Control of GTP tunnels and IP service flows
• SGW Mobility control
• User Plane tunnels for
DL and UL data delivery
•Indirect forwarding of DL data
during handovers (in S1-U)
when direct (X2) inter-eNodeB
connection is not available
•Control of GTP tunnels
•GTP tunnels for UL and DL
data delivery
S1-U

Packet Data Network (PDN) Gateway (PGW)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

Packet Data Network (PDN) Gateway (PGW)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRFS1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
• Control of User Plane tunnels
• UP tunnels for UL and DL data delivery
• IP flows of user data
• Policy and Charging
Control requests
• PCC rules
S1-U
eNB

Home Subscriber Server (HSS)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRF
S1-U
S1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
eNB

Home Subscriber Server (HSS)
•Applications
•Internet
SGW PGW
MME
eNB
UE
PSRFS1-MME
S11
S6a
Rx
Gx
S1-U S5/S8
X2
HSS
SGi
User Plane
Control Plane
• Contains users’ subscription data
S1-U
eNB

September 2015
Session 3:
Technical Aspects of LTE

LTE air-interface and radio network
OFDM
Why OFDM?
 To overcome the effect of multi path fading problem available in UMTS, LTE uses Orthogonal Frequency
Division Multiplexing (OFDM) for the downlink.
 OFDM uses a large number of narrow sub-carriers for multi-carrier transmission to carry data.

OFDM
Pros & Cons of OFDM
+ Good performance in frequency selective fading channels;
+ Good+ Low complexity of base-band receiver;
+ Robust against inter-symbol interference (ISI)
+ Less sensitivity to timing-offsets
+ Ease of implementation in terms of architecture (i.e. FFT & IFFT blocks)
- High peak to average power ratio (PAPR)
- Lower data-rate efficiency due to CP overhead
- High sensitivity to carrier frequency offsets

Inter-Carrier-Interference (ICI)
 Overlap of neighboring subcarriers → Inter Carrier Interference (ICI).

inter-symbol interference (ISI)
 In telecommunication, inter-symbol interference (ISI) is a form of distortion of a signal in which
one symbol interferes with subsequent symbols.

Cyclic Prefix
 The Cyclic Prefix represents a guard period at the start of each OFDMA symbol which provides
protection against multi-path delay spread.
 Cyclic Prefix guarantees the suppression of ISI and ICI!

Length of CP

SC-FDMA
 LTE uses a pre-coded version of OFDM called Single Carrier Frequency Division Multiple Access (SC-
FDMA) in the uplink.
 For uplink transmissions, OFDM is not ideal due to high PAPR
 High PAPR requires expensive and inefficient power amplifiers with high requirements on linearity,
which increases the cost of the terminal and drains the battery faster.

Symbols, slots, radio blocks & frame structure in OFDM
Frame Structure
 Two radio frame structures defined:
1. Frame structure type 1 (FS1): FDD.
2. Frame structure type 2 (FS2): TDD.
 A radio frame has duration of 10 ms.
 A resource block (RB) spans 12 subcarriers over a slot duration of 0.5 ms.
 One subcarrier has bandwidth of 15 kHz, thus 180 kHz per RB.

FDD frame structure
 Subcarrier spacing is set to 15 KHz regardless of overall channel BW.
 To reduce the overhead of resource assignment, 7 consecutive symbols on 12 successive subcarriers are
 grouped into an Resource Block(RB).
 An RB occupies 1 slot of a duration of 0.5 milliseconds.
 A Subframe consists of 2 RBs (i.e., 2 slots)and hence is of a duration of 1 millisecond.
 Each frame has a duration of 10 milliseconds consisting of 10 subframes

TDD frame structure
 Two

Resource Grid

Uplink and Downlink Channels
FDD
 In FDD mode (Operation in paired spectrum) all subframes of a carrier either used for uplink or in
downlink

TDD
 Using time division duplex (TDD), the base station and mobile transmit and receive on the same carrier
frequency but at different times.
 Advantages of using LTE TDD: it is possible to dynamically change the up and downlink balance and
characteristics to meet the load conditions.

TDD
 7 up / downlink configurations have been defined.
 In TDD mode, The first and sixth subframes (subframes 0 and 5) are always allocated to the DL and The
other sub-frames can be allocated to UL or DL
 The 1st and 6th subframes contain synchronization signals.

FDD vs. TDD
 FDD and TDD modes have different advantages and disadvantages.
 In FDD mode, the bandwidths of the uplink and downlink are ﬁxed and are usually the same. This makes
it suitable for voice communications, in which the uplink and downlink data rates are very similar.
 In TDD mode, the system can adjust how much time is allocated to the uplink and downlink. This makes
it suitable for applications such as web browsing, in which the downlink data rate can be much greater
than the rate on the uplink.
 TDD mode can be badly affected by interference if, for example, one base station is transmitting while a
nearby base station is receiving.

Modulation
Enhanced Bits/Symbol
8-PSK (3 Bits per symbol)

MIMO
Advantages:
 Improve capacity (Spectral Efficiency)
 Extended Coverage
 No allocation of extra spectrum
 High peak data rates

QoS
QoS parameters
 A bearer has two or four QoS parameters, depending on whether it is a real-time or best effort service:
1. QoS Class Indicator (QCI)
2. Allocation and Retention Priority (ARP)
3. Guaranteed Bit Rate (GBR) ; (real-time services only)
4. Maximum Bit Rate (MBR) ; (real-time services only)

QoS
QoS Class Indicator (QCI)
 The 3GPP has defined a series of standardized QCI types.
 For first deployments, a majority of operators will likely start with three basic service classes: voice,
control signaling, and best-effort data.

QoS
Guaranteed Bit Rate & Non-GBR Bearers
 There are two major types of bearers:
1. Guaranteed Bit Rate
 A GBR bearer has a minimum amount of bandwidth that is reserved by the network
 GBR bearers are used for real-time services, such as conversational voice and video.
 If implemented properly, GBR bearers should not experience packet loss on the radio link or the IP
network due to congestion.
 GBR bearers will also be defined with the lower latency and jitter tolerances that are typically required
by real-time services.
2. Non-Guaranteed Bit Rate.
 Non-GBR bearers, do not have specific network bandwidth allocation.
 Non-GBR bearers are for best-effort services, such as file downloads, email, and Internet browsing.
 These bearers will experience packet loss when a network is congested.

September 2015
Session 4:
LTE; Continual Evolution

LTE: continual evolution
LTE Release overview
Rel-8
Rel-9
Rel-10
Rel-11
Rel-12
Rel-8 (2008)
• High spectral efficiency
• Very low latency
• variable bandwidth
• Simple Architecture
• FDD and TDD mode
• SON Support
• HeNB /CSG support
Rel-9 (2009)
• eMBMS
• LTE MIMO: dual layer
• Enhanced Home eNodeB
• Positioning
Rel-10 (2011)
• Relays
• HetNet
• MBMS enhancement
• enhanced SON
Rel-11 (2013)
• Carrier Aggregation
• E-PDCCH
• Network based positioning
• enhanced SON
Rel-12 (2014)
• small cell enhancements
• WiFi offload & interworking
• Public safety
• Enhanced Carrier Aggregation
• D2D

Important features of LTE Release
1. Self Organizing Networks
Self organizing network functionalities are commonly divided into three major sub functional groups, each
containing a wide range of decomposed use cases.
1. Self Configuration functions
2. Self Optimization functions
3. Self healing functions
SON
Optimization
Configurationhealing

1. Self Organizing Networks
Optimization ConfigurationHealing
Coverage and Capacity Optimization (CCO)
Mobility Robustness Optimization (MRO)
Mobility Load Balancing (MLO)
Inter-Cell Interference Coordination (ICIC)
Random Access Channel (RACH)
Energy Savings
Base station self configuration
Automatic Neighbor Relation (ANR)
Cell Outage Detection and Compensation
Automated Fault Identification

2. Relays
The types of relays can be roughly separated by the layers within the protocol architecture that are
involved in the relay transmission:
• Layer 1 (L1) Relay. Also called Amplify-and-Forward Relay, Layer 1 (L1) Relay is simple and easy to
implement through RF amplification with relatively low latency.
• Layer 2 (L2) Relay. Layer 2 (L2) Relay performs the decode-and-forward operation and has more
freedom to achieve performance optimization.
• Layer 3 (L3) Relay. Also called Self-Backhauling, Layer 3 (L3) Relay has less impact to eNB design and it
may introduce more overhead compared with L2 Relay.

3. Carrier Aggregation
Carrier aggregation across:
 multiple carriers,
 multiple bands,
 and across licensed and unlicensed spectrum.
Advantages:
 Higher peak data rates
 Higher user data rate and lower latencies for all users
 More capacity for typical ‘bursty’ usage (such as YouTube, Facebook, Twitter, Skype…)
 Leverages all spectrum assets

3. Carrier Aggregation
 Three different modes being defined for carrier aggregation:

4. Heterogeneous Network
The heterogeneous network can be characterized by deployments where low power nodes are placed as
an underlay throughout a macrocell deployment.
These low power nodes include micro, pico, Remote Radio Heads (RRH), relay and femto nodes.
The most challenging aspect in the deployment of heterogeneous networks is the interference issues
generated by sharing the carrier with the overlaid macro nodes.

September 2015
Session 5:
New Services and Better Experiences

VoLTE
Why Voice over LTE?
VoLTE is necessary because:
 Voice is still dominant source of revenue
 To provide better experiment of service
 Competing with OTT players

VoLTE
Method to provide Voice in LTE
CSFB: Fallback to CS domain when voice service is requested
•Pros
- Service Consistency
- Using existing CS Infrastructure
•Cons
- Call setup delay
- Heavy signaling
- MSC Upgrade( for SGs interface)
- No LTE during voice

VoLTE
SV-LTE: Allows UE to access both to LTE and WCDMA/GSM/CDMA simultaneously
•Pros
-No new modification is required
-Using existing CS Infrastructure
-Simultaneous service available between voice and data
• Cons
-Cost of Handset increase due to dual modem chip
-High battery utilization

VoLTE
SR-VCC: Allows UE with active call to switch to CS network when LTE Coverage is lost
•Pros
-Service Consistency
-Lower Call Setup times than CSFB
• Cons
-Requirement of an IMS core network ( SCC-AS )
-Session transfer and remote UE update need time
-MSC Upgrade ( for Sv interface )

VoLTE
VoLTE: IMS based voice over LTE services
• Pros
-Provide Rich Communication Suite
-Fast call setup time
-Fixed and Mobile Convergence
• Cons
-Need ecosystem to support interoperation
with legacy services & roaming.

VoLTE
HD Voice & Video Calls
 2.2 times wider bandwidth for voice signal
Bandwidth for 3G : 300 ~ 3,400Hz
Bandwidth for VoLTE : 50 ~ 7,000Hz
 Up to 20 times faster call setup time
Call Setup time in 3G : 5 sec
Call Setup time in VoLTE : 0.25 ~ 2.5 sec
 12 times improved resolution for video call
Resolution in 3G Video call : QCIF 176 x 144
Resolution in VoLTE Video call : VGA 640 x 480

VoLTE
QoS ( Quality of Service ) Support
 Provide Quality of Service by separating default bearer channel and dedicated bearer channel in priority –
Service differentiation with OTT Players.

VoLTE
VoLTE vs OTT Comparison
OTT mVoIPVoLTEParameter
Application ProviderNetwork OperatorProvider
Non IMSIMSCore Network
QoS not supportedQoS supportedQoS
Depends on network environmentHD VoiceQuality

LTE Broadcast
introduction
 LTE Broadcast offers MNOs a profitable business proposition through service differentiation, new revenue
opportunities, and more efficient distribution of live and other digital media.
 Subscribers like to be able to consume content anytime, anywhere. As a result, new business models are
emerging in which the line between fixed and mobile is becoming indistinct.
 Mobile data traffic is expected to grow 12-fold by the end of 2018 , driven mainly by video.
 LTE Broadcast is supported for all defined bandwidths and formats of LTE, including FDD, TDD, and carrier
aggregation (CA).

LTE Broadcast
Broadcast & Unicast
Broadcast:
• One data channel per content
• Limited data channels and unlimited
number of users
• Offer popular services over dense areas
Unicast:
• One data channel per user
• Unlimited channels and limited
number of users
• Any content, any time, anywhere

LTE Broadcast
Use cases Overview
1. Premium Event Service
o National live events, Seasonal sports event, Venue casting
2. Media Services
o Popular TV and video service, Podcasting – Publishing, …
3. OTT Optimization
o “Netflix” or “Hulu” type services, Breaking news (National broadcast), Advertising service
4. Data Offload
5. Complementing Emergency Services
o Public Safety

Data
Streaming
Mobile video in general is forecast to grow by
around 45% annually through to 2020,
when it will account for around 55% of all
mobile data traffic.
In many mobile networks today,
40–60 percent of video traffic is fro YouTube!

Data
Data Growth
20202014
Share of total
mobile traffic
55%45%Video
15%15%Social networking
5%10%Web browsing
2%2%Audio
Display pixels and average data consumption
Increasing screen size and resolution, as well
as the availability of high-speed networks fuel
the demand for mobile video.

Data
New Apps
In each country,
two-thirds of all app traffic
on smart devices is from its
top five apps

M2M
Connected World
 Globally, almost 80 percent of M2M devices are GSM-only. will decrease to around 25 percent in 2020.
 In 2018, it is expected that 3G/4G will represent over 50 percent of all active M2M subscriptions.
 LTE M2M device penetration is expected to increase from around 3 percent today to around 20–30
percent in 2020.

September 2015
Thanks for your attention!
Mohammad Hajizadeh
LTE Technical Manager
mr.hajizade@gmail.com

LTE Workshop

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