1. Background: 4G/3G Mobile Networks
Lecture 1:
(1)

2. Jargons Mobile networks use many jargon and abbreviations
LTE, EPS, Node B, eNodeB
Nested acronyms are common
GERAN = GPRS Evolution Radio Access Network
LTE is often referred to as Evolved Packet System (EPS) in technical situations
Learn the jargon and acronyms gradually
There is an associated glossary and cheat-sheet
I do not remember many
CS590 (Peng)

3. Outline Evolution of mobile networks Network architecture
Network operations and protocol stack
CS590 (Peng)

4. Ubiquitous Mobile Network Services
In-building
Outdoor
Walking
Driving
Subway
High-speed train
Today, mobile internet anywhere, anytime.
(2) Today, Almost everyone can use mobile Internet anytime, anywhere.
%mobile Internet has become an important part of our everyday life.
CS590 (Peng)

5. Ubiquitous Mobile Network Services5
Global Mobile Data Traffic
7.2 exabytes/month in 2016 (63% growth)
18 fold growth in the past five years
7 fold growth by 2021 (49 exabytes/month)
Soruce:
(1) We still witness increasing growth.
Forecast: Mobile Network Through 2021
49 exabytes/month (6.8x growth)
4G: 75% traffic and 53% connections
5G: 1.5% traffic and 0.2% connections
98% traffic &75% connections from “smart” devices
he Mobile Network Through 2021
Mobile data traffic will reach the following milestones within the next 5 years:
●   Monthly global mobile data traffic will be 49 exabytes by 2021, and annual traffic will exceed half a zettabyte.
●   Mobile will represent 20 percent of total IP traffic by 2021.
●   The number of mobile-connected devices per capita will reach 1.5 by 2021.
●   The average global mobile connection speed will surpass 20 Mbps by 2021.
●   The total number of smartphones (including phablets) will be over 50 percent of global devices and connections by 2021.
●   Smartphones will surpass four-fifths of mobile data traffic (86 percent) by 2021.
●   4G connections will have the highest share (53 percent) of total mobile connections by 2021.
●   4G traffic will be more than three-quarters of the total mobile traffic by 2021.
●   More traffic was offloaded from cellular networks (on to Wi-Fi) than remained on cellular networks in 2016.
●   Over three-fourths (78 percent) of the world’s mobile data traffic will be video by 2021.
Source: Cisco Visual Networking Index, 2017: Global Mobile Data Traffic Forecast Update, 2016–2021 White Paper
CS590 (Peng)

6. Ubiquitous Mobile Network Services
Smartphones: primary internet access points
By 2021, 98% traffic and 75% connections from “smart” devices
4G: 75% traffic and 53% connections
5G: 1.5% traffic and 0.2% connections
CS590 (Peng)

7. Empowered by Mobile Networks
Internet
… ...
Mobile
Client
Network
Infrastructure
To connect these smartphones and the Internet, the key enabler is the underlying mobile networked system.
Mobile clients first get wireless access to the base stations and then traverse several gateways in the rest mobile network infrastructure and finally reach the external Internet.
(3) So far and also in the coming years, this is still the only large-scale, wide-area wireless network system, which complements the wired Internet.
the only large-scale, wide-area wireless network system in par with the Internet
CS590 (Peng)

8. Empowered by Mobile Networks
… ...
Wireless
(radio access technology)
Mobile
Client
Network
Infrastructure
To connect these smartphones and the Internet, the key enabler is the underlying mobile networked system.
Mobile clients first get wireless access to the base stations and then traverse several gateways in the rest mobile network infrastructure and finally reach the external Internet.
(3) So far and also in the coming years, this is still the only large-scale, wide-area wireless network system, which complements the wired Internet.
CS590 (Peng)

9. Mobile Network Evolution1G
AMPS, NMT
TACS 2G
GSM/GPRS/ EDGE
cdmaOne 3G
WCDMA/HSPA+
CDMA2000/EVDO
TD-SCDMA 4G
LTE
LTE-A
1G G G G G
Mid 1980s s s s s
analog
voice
Digital voice
+ Simple data
Mobile
broadband
Mobile Internet
More & faster
All these are empowered by the evoluation of mobile networks.
Today, the world is advancing to 4G LTE and even LTE advanced.
At this time point, almost everyone knows that 3G/4G mobile networks are everywhere.
This fact can be easily supported by many numbers.
For example, 3G/4G have been deployed in 203 countries; serving 6.8 billions user.
By 2014 (this year), it will go beyond our global population.
Last year, more than half a billion smartphones and tablets are shipped,
The market is $1 trillion by 2016.
And so on…
=========================================================
Mobile network is the largest scale wireless infrastructure.
It covers the whole planet and serves billions of users.
It provides mobile users with data service and carrier-grade quality voice service
CS590 (Peng)

10. Standards Body: 3GPP An international standards body
Evolves and standardizes GSM, UMTS, LTE among others
The 3rd Generation Partnership Project (3GPP) unites [Six] telecommunications standard development organizations (ARIB, ATIS, CCSA, ETSI, TTA, TTC), known as “Organizational Partners” and provides their members with a stable environment to produce the highly successful Reports and Specifications that define 3GPP technologies
We will primarily discuss 3GPP standards
There are other standards, like 3GPP2, 5GPP
CS590 (Peng)

11. Cellular Network Standards
3GPP2
3GPP
Circuit Switched
3GPP
Packet Switched
Wimax Forum
Generation 2G
GSM
cdmaOne
GPRS
2.5G
2.75G
EDGE 3G
UMTS
CDMA2000
3.5G
HSPA/+
CDMA EV-DO 4G
LTE
UMB
WiMAX
CS590 (Peng) 11

12. What is LTE? LTE stands for “Long Term Evolution”
Fourth-generation (4G) cellular technology from 3GPP
Deployed worldwide
4G LTE: First global standard
Increased speed
IP-based network (All circuits are gone/fried!)
New air interface: OFDMA (Orthogonal Frequency-Division Multiple Access), MIMO (multiple antennas)
Also includes duplexing, timing, carrier spacing, coding...
New service paradigm (e.g., VoLTE)
CAT 3, CAT 4, CAT 6 (different radio technology),  different speed
All implementations must meet baseline requirements
Increased speed
IP-based network (All circuits are gone/fried!)
New air interface: OFDMA (Orthogonal Frequency-Division Multiple Access), MIMO (multiple antennas)
Also includes duplexing, timing, carrier spacing, coding...
CS590 (Peng)

13. What is LTE? LTE is always evolving and 3GPP often has new “releases”
First release: Rel-8
Current: Rel-11, Rel-12
Toward LTE-Advanced (4.5G)
CAT 3, CAT 4, CAT 6 (different radio technology),  different speed
Enhancement over time (CAT3, CAT 4, CAT 6),
All implementations must meet baseline requirements
Increased speed
IP-based network (All circuits are gone/fried!)
New air interface: OFDMA (Orthogonal Frequency-Division Multiple Access), MIMO (multiple antennas)
Also includes duplexing, timing, carrier spacing, coding...
CS590 (Peng)

14. Evolution from 3G to 4G LTE
2000s
Faster and Better
Mobile broadband
300+ Mbps 3G
2000s
Mobile
Broadband
42+ Mbps
4G LTE: First global standard
Increased speed
IP-based network (All circuits are gone/fried!)
New air interface: OFDMA (Orthogonal Frequency-Division Multiple Access), MIMO (multiple antennas)
Also includes duplexing, timing, carrier spacing, coding...
New service paradigm (e.g., VoLTE)
CS590 (Peng)

15. Network Architecture Evolution2G 3G 4G
Circuit-switching for voice
Circuit-switching for voice
Packet-switching for data
Packet-switching for everything
IP-based
Telecomm
Infrastructure
IP-based Internet
CS590 (Peng)

16. Inter-Generation Technologies
CS networks need to be able to connect with PS networks and other distinct cellular networks
The internet is a good example of PS network
GPRS (General packet radio service)
2.5G packet switched technology
EDGE (Enhanced Data Rates for GSM Evolution)
2.75G packet switched technology
HSPA (High Speed Packet Access)
3.5/3.75 packet switched data technology
There were a few quick iterations on this technology, thus “variants”
CS590 (Peng)

17. 2G Network Architecture (GSM)
Operations and Support Subsystem
BTS UE
MSC
HLR/AuC
BSC
Base Station Subsystem
Network Subsystem 17
CS590 (Peng)

18. 2G Based on Circuit Switching (CS)
End-end resources reserved for “call”
link bandwidth, switch capacity
dedicated resources: no sharing
circuit-like (guaranteed) performance
call setup required
CS590 (Peng)

19. CS Signaling used to setup, maintain teardown VC
used in 2G, as well as in 3G
not used in today’s Internet
application
transport
network
data link
physical
application
transport
network
data link
physical
5. Data flow begins
6. Receive data
4. Call connected
3. Accept call
1. Initiate call
2. incoming call
CS590 (Peng)

20. 4G Network Architecture (LTE)
4G Packet-Switched
Let us look at the mobile network architecture to see how these services are made possible.
Here it is a 4G LTE network architecture which only supports packet-switched service.
It consists of two parts:
First, base stations to offer radio access
Second, core network which consists of MME (Mobility Management Entity) and 4G PS gateways .
The MME is used to manage user mobility, e.g., location update.
The 4G PS Gateways route packets between Internet and 4G Base stations
MME: Mobility Management Entity
BS: Base Station (4G: eNodeB)
CS590 (Peng)

21. waiting for output link
Packet Switching (PS) C A
Sequence of A & B packets does not have fixed pattern, bandwidth shared on demand  statistical multiplexing
Store-and-forward at intermediate routers
Used by the Internet
statistical multiplexing B
queue of packets
waiting for output link D E
CS590 (Peng)

22. PS Signaling no call setup at network layer
routers: no state about end-to-end connections
no network-level concept of “connection”
packets forwarded using destination host address
packets btw same source-dest pair may take different paths
application
transport
network
data link
physical
application
transport
network
data link
physical
1. Send data
2. Receive data
CS590 (Peng)

23. 3G/4G Network Architecture
4G Packet-Switched
3G Packet-Switched
Now we take a look at 3G network architecture.
Similar to 4G LTE, it has Base station and core networks.
The major difference is that 3G supports both Circuit-Switched and Packet-Switched services.
3G CS Gateways are used to connect to 3G base stations and telephony networks.
3G PS Gateways plays role similar to 4G PS Gateway.
The main difference is that 3G PS Gateways are responsible for control-plane and data-plane functions at same.
In 4G LTE, the control-plane functions are moved to MME.
3G Circuit-Switched
CS590 (Peng)

24. (radio access technology)
So far, Our Focus
We mainly focus on current 3G/4G systems, particularly 4G LTE network
… ...
Wireless
(radio access technology)
Mobile
Client
Network
Infrastructure
CS590 (Peng)

25. Outline Evolution of mobile networks Network architecture
Network operations and protocol stack
CS590 (Peng)

26. Operations Two main planes in operation in parallel:
Data plane (also called User plane): content delivery
Control plane: signaling functions
There is an additional plane that works with the above two planes:
Management plane: configurations, monitoring
CS590 (Peng)

27. Illustration of Data and Control Planes
Network
Infrastructure
Application
Transport IP IP
Data-plane
Control-
Plane
Data-plane
Control-
Plane
CS590 (Peng)

28. Illustration of Data and Control Planes28 28
EPS: Evolved Packet System
PDCP: Packet Data Convergence Protocol
RLC: Radio Link Control
MAC: Medium Access Control
CS590 (Peng)

29. Data-Plane Protocols: IP + lower layers
Packet Data Convergence Protocol (PDCP) – header compression, radio encryption
Radio Link Control (RLC) – Readies packets to be transferred over the air interface
Medium Access Control (MAC) – Multiplexing, QoS
@UE (IP)
@eNB (IP)
PDCP
PDCP
RLC
RLC
MAC
MAC
PHY
PHY
Wireless technology, main evolution across different generations and releases are in PHY layer
CS590 (Peng)

30. Control-Plane Protocols
Control utilities: mobile network specific
Different from Internet counterparts
Data-plane
Internet
Control-plane
P3: Conn.
context
(QoS)
Connectivity Management
It means that the network side implements complex functions.
(2) To support data delivery in the data-plane, it has to support rich control-plane functions like radio resource control, mobility support, connectivity management, QoS control etc.
(3) They are much more complex than the control in the Internet.
P2: Location
update
Mobility Management (MM)
P1: Radio conn. setup
Radio Resource Control (RRC)

31. Control-Plane Protocols in 4G/3G
Variants for same/similar control functions
Hybrid 4G/3G systems
Domains separated for voice (CS) and data (PS)
(1 ) Layered protocol stack
(2) Variants
(3) Complicated (rich set of control protocols)
CS590 (Peng)

32. Distributed Operations: Device, base station, core networks32
CS590 (Peng)

33. Put Them Together Setting up data service in 4G Internet Data-plane
Control-plane
We use one most common operation to explain how they work together.
CS590 (Peng)

34. Data and Control Planes in LTE
eNodeB, S-GW and P-GW are involved in session setup, handoff, routing
User Equipment (UE)
Gateway (S-GW)
Mobility Management Entity (MME)
Network Gateway
(P-GW)
Home Subscriber Server (HSS)
\Station (eNodeB)
Base Station
Serving
Packet Data
Control Plane
Data Plane

35. Setting Up Data Service in 4G
(1) Setup radio connection 35
User
Equipment
4G BS
MME
Others
(HSS, GWs)
RRC Connection Request
RRC Connection Setup
4G-RRC
4G-RRC
RRC Connection Complete
(2) Registration (attach)
(3) Authentication
Attach Request
Authentication Request
4G-MM
Authentication Response
4G-MM
HSS
Attach Accept
Attach Complete
(4) Setup Connectivity Context
(e.g., IP, routing path, QoS)
Public Data Network Connectivity Request
4G- CM
Activate Bearer Context Request ( )
4G- CM
P-Gw
Activate Bearer Context Accept
PDN: Public Data Network
EPS: Evolved Packet System

36. Setting Up Data Service in 4G
Control-Plane Functions 36
User
Equipment
4G BS
MME
Others
(HSS, GWs)
(1) Setup radio connection
4G-RRC
4G-RRC
(2) Registration (attach)
(3) Authentication
HSS
4G-MM
4G-MM
(4) Setup Connectivity Context
(e.g., IP, routing path, QoS)
4G- CM
4G- CM
P-Gw
(5) data-plane delivery

37. Summary and Discussion
Primer on mobile network: architecture, protocols, operations
And its evolution
And its complexity
Difference from wired Internet and WiFi
What?
Why?
CS590 (Peng)

38. After-class Reading (Optional)
Learn more about control plane protocols and their interactions: SIGCOMM’14
Learn more about radio connection setup: check RRC papers
LTE tutorial and reference:
RRC study:
A Close Examination of Performance and Power Characteristics of 4G LTE Networks, by Junxian Huang, Feng Qian, Alexandre Gerber, Z. Morley Mao, Subhabrata Sen, and Oliver Spatscheck, ACM Mobisys 2012.
MN2: [qian10-rrc3g-imc] Characterizing Radio Resource Allocation for 3G Networks, by Feng Qian, Zhaoguang Wang, Alex Gerber, Z. Morley Mao, Subhabrata Sen, and Oliver Spatscheck, ACM IMC 2010.
MN2: [qian11-aro-mobisys] Profiling Resource Usage for Mobile Applications: a Cross-layer Approach by Feng Qian, Zhaoguang Wang, Alex Gerber, Z. Morley Mao, Subhabrata Sen, and Oliver Spatscheck, ACM Mobisys 2011.
MN2:[balasubramanian09-rrctail-imc] Energy Consumption in Mobile Phones: A Measurement Study and Implications for Network Applications, by Niranjan Balasubramanian Aruna Balasubramanian Arun Venkataramani, ACM IMC (It focuses on energy model. RRC tail is introduced).
*MN2: [athivarapu12-radiojockey-mobicom] RadioJockey: Mining Program Execution to Optimize Cellular Radio Usage, by Pavan Kumar Athivarapu, Ranjita Bhagwan, Saikat Guha, Vishnu Navda, Ramachandran Ramjee, Dushyant Arora, Venkat Padmanabhan, and George Varghese, ACM MobiCom 2012.
CS590 (Peng)

39. Action Items Work on your course project early
Topic and team
Check the reference and reading list
Updates shortly
Next Chapter: 5G apps
CS590 (Peng)