S-72.1130%20Telecommunication%20Systems

1
S-72.1130 Telecommunication Systems

• Overview

2
Practicalities

• Lectures (Tuesdays Thursdays 14-16 in hall S4)
  Timo Korhonen (09 451 2351), Michael Hall (09 451
  2322)
• Tutorials (Wednesdays 14-16 in hall S3) Mika
  Nupponen (09 451 5416), Naser Tarhuni (09 451
  2362)
• Exams
• 25.10.2005, 16-19, s1s4
• 21.12.2005, 9-12, s1 s4
• Much of material in printed handouts, references
  
• James F. Kurose, Keith W. Ross Computer
  Networking, 2nd ed.
• A. Leon-Garcia, I. Widjaja Communication
  Networks, 2nd ed.
• M. Duck, R. Read Data Communications and
  Computer Networks, 2nd ed.
• W. Stallings Data and Computer Communications,
  7th ed.
• Ericsson, Telia Understanding Telecommunications,
  Part I Part II
• Grading Compulsory closed book exam and
  voluntary tutorials et0.15
• Tutorials at http//www.comlab.hut.fi/studies/113
  0/exercises/. First published on 22.9 - return by
  27.9, Return box in E-wing, 3rd floor.
• Homepage http//www.comlab.hut.fi/studies/1130
• Course feedback http//palaute.ee.hut.fi/

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Course Objectives

• To understand basic of Telecommunication Systems
• How why systems operate the way they do?
• What may happen in the future based on present
  state of technology?
• Role of abbreviations???
• Describe standardized protocols systems
  (concepts)
• More important to understand the meaning of
  concept that to remember the exact words where
  abbreviation comes from
• Role of interfaces
• Telecommunication systems are modular, what
  happens in interfaces? This gives idea of
  internal realization and function of modules

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Course Agenda

• Public Switched Telephone Network (PSTN)
• Integrate Services Digital Network (ISDN) and SS7
• Intelligent Network (IN)
• Asynchronous Digital Subscriber Line (ADSL)
• Wireless Local Area Networks (WLANs)
• The Internet
• UDP
• SIP
• QoS MPLS, diff. Serv.
• TCP/IP Suite
• Services
• Telecommunications market

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Networking Subtopics

• User services as
• IN services call last dialed, alternate billing
  services (as calling card, collect call)
• Internet web, email, ftp
• Terminals (modems and PSTN/ISDN phones), user
  interfaces
• Standards (ITU-T, ITU-R, IETF, IEEE,...)
• Routing and switching (unicast - multicast,
  devices protocols RSVP)
• Transmission and links (fibre, coax-cable..)
• Access and transport techniques (flow control,
  error control)
• Signaling (SS7, X.25, Frame relay ...)
• Network management (as OMAP of SS7...)
• Interworking (gateways, bridges ...)
• Network planning

IN Intelligent Network IETF Internet
Engineering Task Force IEEE the Institute of
Electrical and Electronics Engineers, Inc RSVP
Resource ReSerVation Protocol ITU International
Telecommunications Union SS7 Signaling System 7
(in ISDN) OMAP Operation and Maintenance
Application Part
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Information Society

• Information and Communication Anytime, Anywhere,
  and in Any Form
• Key development fields
• To understand how networks/terminals/services
  evolve consider especially services because all
  network costs are paid by service users

Services
Global Market
Legislation /Regulation /Standardization
Technology
Services shape telecommunications evolution and
effect greatly on which technology is chosen!
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Paradigm Shift
Low-rate data modems (V.90)
Speech
Old view
Current view
Other computers agent-programs (M2M)
MMS
SMS
DVB-H
VoIP
smtp
http
ftp
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Evolving Telecommunication Services
2.5G-3G Services
2G Services
PSTN-originated services
Call Holding/ Call Waiting
International Roaming
Interactive Games
Instant Messaging/Chat
Call Barring/ Call Forwarding
SMS
Streaming Video, Audio
Pre-paid Services
Voice Mail
Push-adds
Push-to Talk
Catalog Enquiry
Basic Voice BW 4 kHz
Internet Access
Data 9.6 Kb/s 380 kb/s
Data up to 2 Mb
10 Mb/s (HSDPA)
Data 56 kb/s (V.90)
Mobile Commerce
MMS
WAP
Circuit Switching Voice services, IN-services,
limited data
III Play
Rich Call See what I see!
13 Kb/s Voice
Location Identification - Presence
Circuit/Packet Switching Mobility, Data
communication
All-IP Location, mobility management,
presence, personalization, security
III PlayVoIPDVB-HInternet
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Telecommunication Networks
Internal structure can follow different topologies
mesh/star/bus/ring (see supplementary material)

• Core and access parts
• Access part terminated by terminals
• Network nodes and links are optimized for certain
  assumed traffic sources and transmission channels
  
• Model applies for both data (packet) and voice
  networks

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Tasks of a Communication System
Entity 3
Entity 3
Entity 2
Entity 2
interface
Entity 1
Entity 1
Physical connection

• Initialization and release of link/across network
• Synchronization RX TX - carriers, start and end
  of packets
• Information exchange protocols determine
  protocols for communication in entities CSMA,
  CDMA, TCP/IP
• Error control - corrective measures
• Addressing and routing
• Message formatting, source coding
• Therefore, networks realized by following a
  layered structure (as Open System
  Interconnections (OSI) )

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Open System Interconnection (OSI) Layers
Access to OSI environment applications
7. Application
Independence of applications from differences in
data presentations(compression encryption)
6. Presentation
Gateway Layers
5. Session
Establishing, managing and termination
connections (sessionsdialogues) between
cooperating applications
4. Transport
Reliable, transparent data transfer for lower
level data segments or blocks(end-to-end flow
error cntr)
3. Network
Routing switching service for transport layer.
Layer of routers.
Sends data blocks with synchronization, error and
flow control for link layer connections. Layer
of bridges.
2. Data Link
LAN Layers
Transmission of electrical signals in
medium.Layer or repeaters (multiplexing/bit
transmission)
1. Physical
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Each OSI-layer has its Standardized Services
NCP, FTP, Telnet, SMTP, SNMP, LAT, AFP, SMB...
7. Application
ACSE, ROSE, RTSE, ...
6. Presentation
5. Session
NetBIOS, NetBEUI, DNS, ...
4. Transport
SPX, PEP, TCP, UDP, NSP...
3. Network
IPX, RIP, SAP, IDP, IP, ARP, RSVP, ICMP, X.25,
RIP...
IEEE 802.X, HDLC, ANSI X3T9.5, SMT,...
2. Data Link
V.24, V.35, V.90, 10Base5, 10Base2, 10BaseT,
FDDI, SDH, G.703...
1. Physical
Good source for abbreviations http//www.mpirica
l.com/companion/mpirical_companion.html
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Example from mpirical - database
http//www.mpirical.com/companion/mpirical_compani
on.html
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ITU-T Standards

• G - Transmission Systems and media, digital
  systems and networks
• H - Audiovisual and multimedia systems
• I - ISDN
• Q - Switching and signalling
• V - Data communications over PSTN
• X- Data networks and open system communications

Other important standardization organizations -
IEEE (Institute of Electrical and Electronics
Engineers) - IETF (The Internet Engineering Task
Force) - ISO (International Organization for
Standardization) - ETSI (European
Telecommunications Standards Institute)
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Example Retrieving a Document from the Web
The user clicks on a link to indicate which
document is to be retrieved. The browser must
determine the Internet address of the machine
that contains the document. To do so, the browser
sends a query to its local name server. DNS, UDP,
HTTP, FTP, HTML
Addressing
Step
1.
TCP/IP connection
Once the address is known, the browser
establishes a connection to the server process in
the specified machine, usually a TCP connection.
For the connection to be successful, the
specified machine must be ready to accept TCP
connections. TCP/IP
2.
Document specifications
The browser runs a client version of HTTP, which
issues a request specifying both the name of the
document and the possible document formats it can
handle.
3.
Document response
The machine that contains the requested document
runs a server version of HTTP. It reacts to the
HTTP request by sending an HTTP response which
contains the desired document in the appropriate
format. Document sent to the receiver.
4. 6.
Viewing the document, closing TCP/IP
7. 8.
The user may start to view the document. The TCP
connection is closed after a certain timeout
period.
From Leon-Garzia, Widjaja Communication
Networks, 2th ed., Instructors Slide Set
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Different Services Require Different Rates
Maximum Rates of some Transmission
Technologies GSM 14.4 kb/s HSCSD 56 kb/s POTS 56
kb/s GPRS 114 kb/s EDGE 384 kb/s Frame Relay 1.54
Mb/s T-1 1.54 Mb/s ADSL 8 Mb/s Cable modems 52
Mb/s Ethernet 10 M, 100 M, 1G FDDI 100 Mb/s
OC-256 13.3 Gb/s
Telephony
Voice
Broadcasting
Video conferencing
TV/HDTV
Video
Video
Inter-LAN/PBX communications
Data
Fax
Streaming with MPEG, MP3
10k
1M
100M
Bit rate (b/s)
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Streaming Technologies
Major streaming video and streaming media
technologies include RealSystem G2 from
RealNetwork, Microsoft Windows Media Technologies
(including its NetShow Services and Theater
Server), and VDO. Microsoft's approach uses the
standard MPEG compression algorithm for video.
The other approaches use proprietary algorithms.
(The program that does the compression and
decompression is sometimes called the codec.)
Microsoft's technology offers streaming audio at
up to 96 Kbps and streaming video at up to 8 Mbps
(for the NetShow Theater Server). However, for
most Web users, the streaming video will be
limited to the data rates of the connection (for
example, up to 128 Kbps with an ISDN connection).
Microsoft's streaming media files are in its
Advanced Streaming Format (ASF).
Source Searchnetworking.com
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Network Evolution
1995
2010
Terminal
Single system support
Software radio
Multi-system support
Radio interface
GSM, DECT
UMTS/4G
GPRS, EDGE, HSCSD
Trunk /Core
PSTN, ISDN
ATM, ISDN, B-ISDN
TCP-IP/UDP
Services
Voice, low rate data
Modest-rate Internet
Portable, global virtual reality
Multimedia, Virtual reality
Push-to-talk, VoIP
2G Fax/data/ SMS 9.6 kb/s
2G Data compr. 2.5x 9.6 kb/s
2.5G HSCSD 28.8 kb/s
2.5G GPRS 92 kb/s
2.5G EDGE 384 kb/s
3G UMTS 2 Mb/s
3G HSDPA 10 Mb/s
1992
1998
2000
2001
2003
2004
2005
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Speech and Data Communications
Speech
Data
Delays
Limited to 200 ms
Depends on service
Errors
High tolerance
Very limited tolerance
Stream
Continuous Circuit switching
Bursty Packet switching

• Teletraffic can be forced to fixed rate or
  bandwidth as speech in PSTN or in ATM traffic
• Waste of network resources follows if network
  resources can not be reallocated on request
  (statistical multiplexing)

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Symmetry

• Categories
• Asymmetrical channel
• based on idea that downlink traffic is much
  larger that uplink traffic
• Traditionally in access networks (ADSL, Cable
  modems)
• Data over DVB
• Symmetrical channel as in fixed line telephony
• Some services (as P2P) require symmetrical
  traffic channel!
• Point-to-multipoint channel (broadcasting)
• TV (DVB) and Fax are point-to-multipoint
  distributive services
• Webcasting (PointCast news service)
• Rapidly developing Internet services set
  stringent requirements for network infrastructure
  planning
• adaptivity
• service/system upgradability

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Network Topology

• Different topologies in different networks
• BUS - Ethernet
• Ring - FDDI
• Mesh - Internet Number of connections
  requiredN number of nodes
• Selection of topology effects for instance
  applicable MAC scheme network reliability
• IEEE 802 (LAN) technology often applied

Optical star-coupler
Optical networks
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What is Ethernet?
Ethernet is the most widely-installed local area
network (LAN) technology. Specified in a
standard, IEEE 802.3, Ethernet was originally
developed by Xerox and then developed further by
Xerox, DEC, and Intel. An Ethernet LAN typically
uses coaxial cable or special grades of twisted
pair wires. Ethernet is also used in wireless
LANs. The most commonly installed Ethernet
systems are called 10BASE-T (100 m / CAT 3
cables) and provide transmission speeds up to 10
Mbps. Devices are connected to the cable and
compete for access using a Carrier Sense Multiple
Access with Collision Detection (CSMA/CD)
protocol. Fast Ethernet or 100BASE-T provides
transmission speeds up to 100 megabits per second
and is typically used for LAN backbone systems,
supporting workstations with 10BASE-T cards.
Gigabit Ethernet provides an even higher level of
backbone support at 1000 megabits per second (1
gigabit or 1 billion bits per second). 10-Gigabit
Ethernet provides up to 10 billion bits per
second.
Source Searchnetworking.com
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What is FDDI?
FDDI (Fiber Distributed Data Interface) is a set
of ANSI and ISO standards for data transmission
on fiber optic lines in a local area network
(LAN) that can extend in range up to 200 km (124
miles). The FDDI protocol is based on the token
ring protocol. In addition to being large
geographically, an FDDI local area network can
support thousands of users. FDDI is frequently
used on the backbone for a wide area network
(WAN). An FDDI network contains two token
rings, one for possible backup in case the
primary ring fails. The primary ring offers up to
100 Mbps capacity. If the secondary ring is not
needed for backup, it can also carry data,
extending capacity to 200 Mbps. The single ring
can extend the maximum distance a dual ring can
extend 100 km (62 miles). FDDI is a product of
American National Standards Committee X3-T9 and
conforms to the Open Systems Interconnection
(OSI) model of functional layering. It can be
used to interconnect LANs using other protocols.
FDDI-II is a version of FDDI that adds the
capability to add circuit-switched service to the
network so that voice signals can also be
handled. Work is underway to connect FDDI
networks to the developing Synchronous Optical
Network (SONET).
Source Searchnetworking.com
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Quality of Service (QoS)

• ATM, MPLS and UMTS support wide range of services
  that posses different quality of service (QoS)
  requirements.
• Transportation system differentiated into
  constant rate, real-time and higher-latency
  services by Multi-Protocol Label Switching (MPLS)
  or Differentiated Services (DiffServ)
• User services can be divided to different groups,
  depending on QoS requirements. Four traffic
  classes can been identified for ATM
• Conversational class (very delay-sensitive
  traffic)
• Streaming class
• Interactive class
• Background class (the most delay insensitive)
• Hence TCP (Connection-oriented transport-layer)
  is not a good choice if errors can be tolerated
• UDP (Connectionless transport-layer protocol)
  appropriate for many streaming applications
  (error control in upper layers)

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Multiprotocol Label Switching (MPLS)

• Multiprotocol Label Switching is a
  standards-approved technology (IETF RFC 3031)
  for speeding up network traffic flow and making
  it easier to manage. MPLS involves setting up a
  specific path for a given sequence of packets,
  identified by a label put in each packet, thus
  saving the time needed for a router to look up
  the address to the next node to forward the
  packet to. MPLS is called multi-protocol because
  it works with the Internet Protocol (IP),
  Asynchronous Transport Mode (ATM), and frame
  relay network protocols. With reference to the
  standard model for a network (the Open Systems
  Interconnection, or OSI model), MPLS allows most
  packets to be forwarded at the layer 2(switching)
  level rather than at the layer 3(routing) level.
  In addition to moving traffic faster overall,
  MPLS makes it easy to manage a network for
  quality of service (QoS). Note ATM header
  overhead always at least 10 , for MPLS it is
  order of magnitude smaller.

Source Searchnetworking.com
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Security and Secrecy

• Services require security secrecy, e. g.
  reliable, shielded transfer (Example WEP of
  Wi-Fi). Especially important for
• NGN-services that are near to users
• Vulnerable services
• medical/health as tele-surgery
• rescue, police, defense
• Networks can provide this in several network
  levels (problem overheads)
• fixed lines (PSTN, frame relay)
• flexible routing (SS7)
• scrambling or encryption (PLMNs)
• coding or ciphering (in all modern telecom links
  nets)
• Often used concept AAA Authentication,
  Authorization, Accounting

• Message goes to the right receiver
• Others cant do eavesdropping

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What is AAA?

• Short for authentication, authorization and
  accounting, a system in IP-based networking to
  control what computer resources users have access
  to and to keep track of the activity of users
  over a network.
• Authentication is the process of identifying an
  individual, usually based on a username and
  password. Authentication is based on the idea
  that each individual user will have unique
  information that sets him or her apart from other
  users.
• Authorization is the process of granting or
  denying a user access to network resources once
  the user has been authenticated through the
  username and password. The amount of information
  and the amount of services the user has access to
  depend on the user's authorization level.
• Accounting is the process of keeping track of a
  user's activity while accessing the network
  resources, including the amount of time spent in
  the network, the services accessed while there
  and the amount of data transferred during the
  session. Accounting data is used for trend
  analysis, capacity planning, billing, auditing
  and cost allocation.
• AAA services often require a server that is
  dedicated to providing the three services. RADIUS
  is an example of an AAA service.

Source www.webopedia.com
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Network/Service Adaptivity

• Services manifest themselves via various service
  profiles (that may differ within a short time
  period), and thus efficient adaptivity should be
  supported by networks and terminals
• Advanced networks have a tendency to carry
  intelligence in terminals (and not in network
  nodes, exchanges, routers... )
• Reduces signaling traffic
• Moves costs to end-users
• IN (Intelligent Network, ITU-T Q.1200-series)
  solutions developed first for PSTN but typically
  an important part of most networks as in PLMNs
• Enable service flexibility (software radio does
  this in terminals)
• IN services designed in cooperation with terminal
  intelligence

PSTN
PLMN
WLANs
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Development of Data and Voice Networks
Frame Relay - applies virtual circuits - example
to connect LANs - for high quality (links
have modest error correction flow control) -
rates 2-50 Mb/s
Voice/modems in PSTN
Frame Flow Control (HDLC) - service for a pair
of communicating entities - reassures
non-over- whelming communications (packets
could suffocate receiver )
Earlier Scenarios
Leased lines

• Nodes, links layers with well-defined
  (standardized) interfaces
• Network is optimized for certain, assumed traffic
  
• Earlier Voice and data services in PSTN or data
  in dedicated networks (X.25/Frame Relay)
• Nowadays Internet carries both data and voice -
  QoS important!

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CurrentScenario
ISDN, V.90, Cable modem, ADSL etc.
MPLS
Bluetooth Device
WLAN Router
Modified from W. Stallings Data and Computer
Communications, 7th ed (home site lecture slides)
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Example Bluetooth Technology
Connecting devices in SOHO (Small Office/ Home
Office) to your computer
Home networking
Realizing ad-hoc networking with Bluetooth
See also http//www.bluetooth.com/
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What is Bluetooth?

• Bluetooth is an industrial specification for
  wireless personal area networks (PANs).
• Bluetooth provides a way to connect and exchange
  information between devices like personal digital
  assistants (PDAs), mobile phones, laptops, PCs,
  printers and digital cameras via a secure,
  low-cost, globally available ISM short range
  radio frequency.
• Bluetooth lets these devices talk to each other
  when they come in range, even if they are not in
  the same room, as long as they are within up to
  100 metres (328 feet) of each other, dependent on
  the power class of the product. Products are
  available in one of three power classes
• Class 3 (1 mW) is the rarest and allows
  transmission of 10 centimetres (3.9 inches), with
  a maximum of 1 metre (3.2 feet)
• Class 2 (2.5 mW) is most common and allows a
  quoted transmission distance of 10 metres (32 ft)
  
• Class 1 (100 mW) has the longest range at up to
  100 metres.
• The specification was first developed by
  Ericsson, and was later formalized by the
  Bluetooth Special Interest Group (SIG). SIG was
  established by Sony Ericsson, IBM, Intel, Toshiba
  and Nokia, and later joined by many other
  companies as Associate or Adopter members.
  Bluetooth is also IEEE 802.15.1 that specifies
  its radio interface by using frequency hopping.

http//en.wikipedia.org/wiki/Bluetooth
33
Example Public Switched Telephone
Network (PSTN)

• The oldest (1876) bearer network (other ISDN,
  ATM, frame relay, The Internet)
• After 1960 has got many renovations data, fax,
  processor exchanges, PCM, satellite
  communications, network intelligence (IN), ADSL
• Primary characteristics
• Circuit switched connections
• Analog access bandwidth 300-3400 Hz
• Digital access for instance by
• ISDN (2x64 kbit/s 16 kbits/s)
• ADSL - Supports also packet switched connections
• Limited mobility (DECTPABX RF-interface)

34
Network Stratums of PSTN
Wi-Fi (802.11b,g)

• In practical PSTN different networks form
  stratums
• In this example X.25 packetnetwork operates on
  ATM based SDH access stratums.
• ATM forms an efficientinfo pipe (virtual
  circuits)where no address checking or error
  correction is donebut it is left forhigher
  layers

35
Telecommunications Market
End-Users
Content and Service Providers
Service operators/ Telecommunications Networking
Solutions
Physical Telecommunication Network

• Telecommunication network content and technology
  producers, operators and consumers form an
  interoperable hierarchy

36
Telecomm Market Players

• End-users (individuals , companies,
  machine-to-machine communications)
• Information service providers (Telephone catalog
  services designed by a company, giving telephone
  numbers when you give a name or an address
  Eniro)
• Service brokers sell dedicated service packages
  (...MySAP)
• Network operators (...Elisa, Telia, or
  Radiolinja)
• Content providers (...Paramount Pictures)

37
Future Trends

• PLMNs and especially wireless LANs develop very
  fast in home office networks
• Increasing data rates
• QoS very important
• Traffic gets more symmetrical (P2P)
• PSTN
• Is used to transfer more and more data traffic
• Voice services of PSTN use IP (VoIP) and move to
  Internet
• Need of seamless communication of NGN means that
  different networks must link efficiently -gt
  Inter(net)working between different kind of
  networks important (example Bluetooth-WLAN-UMTS)
  

PLMN Public Land Mobile Network, IPInternet
Protocol SLIP Serial line IP
38
Web Resources

• Tutorials, links, abbreviations
  http//searchnetworking.techtarget.com/
• Mpirical bank of abbreviations
  http//www.mpirical.com/ companion/mpirical_compan
  ion.html
• Wikipedia http//en.wikipedia.org
• Note Many standards available online in the
  Library (as for instance ITU-standards )
• Have a look on course reference books homepages!
• 3rd generation PLMN www.w3.org, www.3gpp.org
• Finish Spectral Regulation www.ficora.fi
• IEEE standards www.ieee.org
• ITU standards www.iti.org
• xDSL development www.adsl.com