background for 3G/4G mobile network and wireleless network

background for 3G/4G mobile network and wireleless network

1. Background:
4G/3G Mobile Networks

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
2CS590 (Peng)

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

4. Ubiquitous Mobile Network Services
CS590 (Peng) 4
In-building Outdoor Walking
Driving Subway High-speed train

5. Ubiquitous Mobile Network Services
•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)
5
5
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) 6

7. Empowered by Mobile Networks
Internet
Network
Infrastructure
Mobile
Client
7
… ...
•the only large-scale, wide-area wireless network
system in par with the Internet
CS590 (Peng)

8. Empowered by Mobile Networks
8
Network
Infrastructure
Mobile
Client
… ...
Wireless
(radio access
technology)
CS590 (Peng)

9. Mobile Network Evolution
CS590 (Peng) 9
1G 2G 3G 4G 5G
Mid 1980s 1990s 2000s 2010s 2020s
analog
voice
Digital voice
+ Simple data
Mobile
broadband
Mobile Internet
More & faster
3G
WCDMA/HSPA+
CDMA2000/EVDO
TD-SCDMA
1G
AMPS, NMT
TACS
2G
GSM/GPRS/
EDGE
cdmaOne
4G
LTE
LTE-A

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
CS590 (Peng) 10

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

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)
CS590 (Peng) 12

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)
CS590 (Peng) 13

14. Network Architecture Evolution
15
2G
Telecomm
Infrastructure
IP-based Internet
•Circuit-
switching
for voice
•Packet-
switching for
everything
•IP-based
3G 4G
•Circuit-switching
for voice
•Packet-switching
for data
CS590 (Peng)

15. 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) 16

16. 2G Network Architecture (GSM)
17
UE
BTS
BSC
MSC
Base Station
Subsystem
Network
Subsystem
Operations and Support
Subsystem
HLR/AuC
17
CS590 (Peng)

17. 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) 18

18. CS Signaling
•used to setup, maintain teardown VC
•used in 2G, as well as in 3G
•not used in today’s Internet
CS590 (Peng) 19
application
transport
network
data link
physical
application
transport
network
data link
physical
1. Initiate call 2. incoming call
3. Accept call4. Call connected
5. Data flow begins 6. Receive data

19. 4G Network Architecture (LTE)
Signaling path
Data path
MME 4G Core Network
4G BS
Internet
Phone
4G PS Gateways
MME: Mobility Management Entity
BS: Base Station (4G: eNodeB)
4G Packet-Switched
CS590 (Peng) 20

20. Packet Switching (PS)
•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
CS590 (Peng) 21
A
B
C
D E
statistical multiplexing
queue of packets
waiting for output link

21. 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
CS590 (Peng) 22
application
transport
network
data link
physical
application
transport
network
data link
physical
1. Send data 2. Receive data

22. 3G Packet-Switched
3G/4G Network Architecture
23
Phone
3G BS
3G Core Network
Internet
Signaling path
Data path
MME 4G Core Network
4G BS
Internet
Phone
4G PS Gateways
3G PS Gateways
Telephony
3G CS
Gateways
4G Packet-Switched
3G Circuit-Switched
CS590 (Peng)

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

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

25. 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) 26

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

27. Illustration of Data and Control Planes
CS590 (Peng) 28
PHY
MAC
PDCP
IP
L1
L2
L3
4G-PHY
4G-MAC
4G-RLC
IP
PDCP
Data
Plane
3G 4G LTE
RLC
Control
Plane
Data
Plane
Radio Resource Contol
Mobility Management
Connectivity Mangement
Connectivity
Management
Mobility
Management
Radio
Resource
Control
Session
Management
(SM)
EPS Session
Management
(ESM)
Mobility
Management
(GMM)
Radio Resource Control
(3G-RRC)
4G LTE3G
Call Control
(CM/CC)
Mobility
Management
(MM)
Radio
Resource
Control
(4G-RRC)
Mobility
Management
(EMM)
PS DomainPS DomainCS Domain
2828
EPS: Evolved Packet System
PDCP: Packet Data Convergence Protocol
RLC: Radio Link Control
MAC: Medium Access Control

28. 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
CS590 (Peng) 29
PDCP
RLC
@eNB (IP)
PDCP
RLC
@UE (IP)
MAC
PHY
MAC
PHY

29. 30
Control-Plane Protocols
Internet
Data-plane
Control-plane
P1: Radio conn. setup
P2: Location
update
P3: Conn.
context
(QoS)
Radio Resource Control (RRC)
Mobility Management
(MM)
Connectivity Management

•Control utilities: mobile network specific
–Different from Internet counterparts

30. Control-Plane Protocols in 4G/3G
•Variants for same/similar control functions
–Hybrid 4G/3G systems
–Domains separated for voice (CS) and data (PS)
CS590 (Peng) 31
PHY
MAC
PDCP
IP
L1
L2
L3
4G-PHY
4G-MAC
4G-RLC
IP
PDCP
Data
Plane
3G 4G LTE
RLC
Control
Plane
Data
Plane
Radio Resource Contol
Mobility Management
Connectivity Mangement
Connectivity
Management
Mobility
Management
Radio
Resource
Control
Session
Management
(SM)
EPS Session
Management
(ESM)
Mobility
Management
(GMM)
Radio Resource Control
(3G-RRC)
4G LTE3G
Call Control
(CM/CC)
Mobility
Management
(MM)
Radio
Resource
Control
(4G-RRC)
Mobility
Management
(EMM)
PS DomainPS DomainCS Domain

31. Distributed Operations: Device, base
station, core networks
3G CS Gateway
MME
3G PS Gateway
3G 4G
Core
Network
User
Device
PS CS
Base
Station
3G-RRC
MMMM
CMCM
4G-RRC
MM
CM
CS590 (Peng)
32

32. Put Them Together
•Setting up data service in 4G
CS590 (Peng) 33
Internet
Data-plane
Control-plane

33. Data and Control Planes in LTE
34
•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

34. Setting Up Data Service in 4G
35
User
Equipment
4G BS MME
RRC Connection Request
RRC Connection Setup
RRC Connection Complete
4G-
RRC
4G-
RRC
4G-
MM
Attach Request
Authentication Request
Authentication Response
Attach Accept
Attach Complete
4G-
MM
Public Data Network Connectivity Request
Activate Bearer Context Request (192.168.0.199)
Activate Bearer Context Accept
4G-
CM
4G-
CM
PDN: Public Data Network EPS: Evolved Packet System
(1) Setup radio connection
(2) Registration (attach)
(3) Authentication
(4) Setup Connectivity Context
(e.g., IP, routing path, QoS)
Others
(HSS, GWs)
HSS
P-Gw

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

36. 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) 37

37. 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:
https://www.tutorialspoint.com/lte/
CS590 (Peng) 38

38. 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) 39