9. Original PSTN
9
UTP UTP
• Manual switching directly connected two local loops
• Due to microphone technology, audio BW was 4 kHz
• PSTN is the network
(c) Anuradha Udunuwara
• POTS is the service
10. Analog switched PSTN
10 CO CO
Local loop Telephone Local loop
(analog) network (analog)
(analog)
• Invention of tube amplifier enabled long distance
• Between central offices used FDM spaced at 4 kHz (each cable carrying 1 group
= 12 channels)
(c) Anuradha Udunuwara
12. Data support via voice-grade modems
12
• To send data, it is converted into 4 kHz audio (modem)
• Data rate is determined by Shannon's capacity theorem (there is a maximum data rate (bps) called the
"capacity”, that can be reliably sent through the communications channel. The capacity depends on the BW
and SNR)
(c) Anuradha Udunuwara
14. Digital PSTN
14
Source : http://kingdominique.be/notepro/nyquist-theorem
(c) Anuradha Udunuwara
15. Digital PSTN, Cont.,
15
CO SWITCH
“last mile”
TDM
PSTN digital
“last mile” TDM
Subscriber Line
analog CO SWITCH
LP filter to 4 kHz at input to CO switch (before A/D)
(c) Anuradha Udunuwara
16. Digital PSTN, Cont.,
16
Sample 4 kHz audio at 8 kHz (Nyquist)
Need 8 bits per sample = 64 kbps
Multiplexing 64 kbps channels leads to higher and higher
rates
Only the subscriber line (local loop) remains analog (too
expensive to replace)
(c) Anuradha Udunuwara
18. Digital Local Loop Technologies
18
ISDN
Voice and Data
Longer distance
DSL
Higher speed
Several variants
Different encoding technologies -> different data
transmission rates
(c) Anuradha Udunuwara
20. Access Network
20
Edge of the network
Enable delivery of services for specific markets
Enable the connection of telecommunication
services with subscribers
(c) Anuradha Udunuwara
27. WPAN
27
interconnect devices within a relatively small area,
that is generally within a person's reach
Ex:- Bluetooth, IR, ZigBee, Wi-Fi, NFC
(c) Anuradha Udunuwara
28. WLAN
28
links two or more devices over a short distance using
a wireless
use of spread-spectrum or OFDM technologies may
allow users to move around within a local coverage
area, and still remain connected to the networks
distribution method
Ex:-Wi-Fi
(c) Anuradha Udunuwara
30. WWAN/Cellular (mobile)
30
radio network distributed over land areas called cells, each served by at least one
fixed-location transceiver, known as a cell site or base station (BTS)
each cell characteristically uses a different set of radio frequencies from all their
immediate neighboring cells to avoid any interference
When joined together these cells provide radio coverage over a wide geographic
area. This enables a large number of portable transceivers (e.g., mobile phones,
pagers, etc.) to communicate with each other and with fixed transceivers and
telephones anywhere in the network, via BTS, even if some of the transceivers are
moving through more than one cell during transmission
originally intended for cell phones, today carry both data and voice
Ex:- GSM, GPRS, UMTS, Satellite
(c) Anuradha Udunuwara
35. Mobile Networks
(Global System for
(General Packet (Universal Mobile
Mobile (Evolved Packet
Radio Service) Telecommunications System)
35 Communications) System)
(Evolved Packet Core)
(BSC) (RNC)
(GSM EDGE (Enhanced Data Rates for GSM Evolution) (Universal Terrestrial Radio Access Network) (Evolved UTRAN)
Radio Access Network)
Source: http://www.3gpp.org/LTE (c) Anuradha Udunuwara
41. Vertical to Horizontal
41
Legacy: Future:
Service Specific Networks NGN architecture for services
Service
Service
Service
Service
Service
Service
Control and Signaling Network
rk
Netwo
rk
Netwo
Network
Network
Network
Converged
Network
(c) Anuradha Udunuwara
42. Why NGN?
42
The NGN concept takes into consideration new realities in the
telecommunication industry characterized by factors such as the
need to converge and optimize the operating networks and the
extraordinary expansion of digital traffic
(i.e. increasing demand for new multimedia services, increasing
demand for mobility, etc.)
NGN also aims to tackle important concerns raised from the use of
current IP-based services:
(i.e. QoS and security) (c) Anuradha Udunuwara
43. Definition
43
NGN is a packet-based network able to provide
Telecommunication Services to users and able to make use of
multiple broadband, QoS-enabled transport technologies and in
which service-related functions are independent of the underlying
transport-related technologies. It enables unfettered access for
users to networks and to competing service providers and
services of their choice. It supports generalized mobility which will
allow consistent and ubiquitous provision of services to users.
[ITU-T Recommendation Y.2001 (12/2004) - General overview of NGN]
(c) Anuradha Udunuwara
44. Fundamental aspects
44
Packet-based transfer
Separation of control functions among bearer capabilities, call/session, and application/service
Decoupling of service provision from transport, and provision of open interfaces
Support for a wide range of services, applications and mechanisms based on service building blocks (including real
time/streaming/non-real time services and multi-media)
Broadband capabilities with end-to-end QoS and transparency
Interworking with legacy networks via open interfaces
Generalised mobility
Unfettered access by users to different service providers
A variety of identification schemes which can be resolved to IP addresses for the purposes of routing in IP networks
Unified service characteristics for the same service as perceived by the user
Converged services between Fixed and Mobile networks
Independence of service-related functions from underlying transport technologies
Support of multiple last mile technologies
Compliant with all Regulatory requirements, for example concerning emergency communications and security/privacy, etc.
(c) Anuradha Udunuwara
49. Segments of NGN Architecture
49
VoIP
IMS Controllers
Control and Signaling Video
CDMA Network Application
Customer FTTx Core Non-IMS Controllers
Equipment Access Network Data
Network Aggregation
xDSL Network IM
Wimax
User Access Aggregation Core Control and Application
Equipments Network Network Network Signaling Network
Network
(c) Anuradha Udunuwara
50. Next Generation Access Options
50
Next
TDM NGN Generation
POTS ADSL
V5.2 ADSL2+ Access
FTTx, ETH
VDSL WiMAX, LTE
VDSL2
(c) Anuradha Udunuwara
56. Migration to an IP converged network
Legacy NGN
Multiple Applications Multiple Applications
Multiple Control Layers Single Control Layer
Multiple Transport Networks Single Transport Network
Multiple Access Network Multiple Access Network
Multiple Access Connection Single Access Connection
56 (c) Anuradha Udunuwara
57. Access network migration (example)
Current Short Term Long Term
AGW, C5 switch AGW (Cu)
FTTx
Data Network AGW (Cu)
Metro Ethernet Metro Ethernet Metro Ethernet
CDMA CDMA
2G/3G/3.5G 2G/3G/3.5G LTE
WiMAX WiMAX
57 (c) Anuradha Udunuwara
58. Issues with Legacy Networks
58
Low bandwidth
No flexibility to scale
High cost of installation
Slow provisioning
Bandwidth growth inflexible/non-linear
Limited by multiplexing hierarchy
TDM-based access: inefficient for converged data
(c) Anuradha Udunuwara
59. Understanding the BIG picture
59
Revenue
generation
Infrastructure
enabler
OPEX reduction
and efficiency
gain
(c) Anuradha Udunuwara
61. About the Author
61
Eng. Anuradha Udunuwara is a Chartered Engineer by profession based in Sri Lanka. He has nearly a decade
industry experience in strategy, architecture, engineering, design, plan, implementation and maintenance of CSP
Networks using both packet-switched (PS) and Circuit-Switched (CS) technologies, along with legacy to NGN
migration. Eng. Anuradha is a well-known in the field of CSP industry, both locally and internationally.
Graduated from University of Peradeniya, Sri Lanka in 2001 with an honors in Electrical & Electronic Engineering,
Eng. Anuradha is a corporate member of the Institution of Engineers Sri Lanka, a professional member of British
Computer Society, a member of Institution of Electrical & Electronic Engineers, a member of Institution of
Engineering & Technology (formerly Institution of Electrical Engineers), a member of the Computer Society of Sri
Lanka, a life member of Sri Lanka Association for the Advancement of Science, senior member of the Carrier
Ethernet Forum, member of the Internet Society, member of the Internet Strategy Forum, member of the Internet
Strategy Forum Network, member of the Ethernet Academy, member of the NGN/IMS forum and member of the
Peradeniya Engineering Faculty Alumni Association. He is also an ITIL foundation certified and the only MEF-CECP in
the country.
In his spare time Anuradha enjoys spending time with his family, playing badminton, photography, reading and
travelling.
He can be reached at udunuwara@ieee.org
(c) Anuradha Udunuwara
