Mobile Communication and Mobile Computing

1
Mobile Communication andMobile Computing

• Prof. Dr. Alexander Schill
• TU Dresden, Computer Networks Dept.
• http//www.rn.inf.tu-dresden.de

2
Contents

• 1. Motivation
• 2. Mobile Communication
• History
• Principles
• Media Access Methods
• Mobile Radio Networks Overview
• GSM
• HSCSD, GPRS
• UMTS

3
Contents

• 2. Mobile Communication (Continuation)
• Broadband-Radio Systems
• Wireless Local-area Networks (IEEE 802.11,
  Bluetooth etc.)
• Satellite-based Systems

4
Contents

• 3. Mobile Computing
• Layer 3
• MobileIP v4 v6
• DHCP
• Layer 4
• Higher Layers and Services
• WAP, XML
• Mobile RPC
• CODA, Databases
• Mobile Agents
• Middleware for spontaneous networking
• Services and system support for Mobile Computing

5
Literature

• Roth, J. Mobile Computing, dpunkt-Verlag,
  2002 Very good overview to mobile communication
  and mobile computing
• Schiller, J., Mobilkommunikation, Techniken für
  das allgegenwärtige Internet, Addison-Wesley,
  2000 Mobile Communication principles and Mobile
  Computing
• Bernhard, Walke Mobilfunknetze und ihre
  Protokolle, 2 Bände. Teubner, 2000Principles,
  GSM, UMTS and other cellular Mobile Radio
  Networks Vol.1 Circuit Switched Radio,
  Cordless Phone Systems, W-ATM, HIPERLAN,
  Satellite Radio, UPT Vol.2
• Schumny, Harald Signalübertragung, Friedrich
  Vieweg Sohn, Braunschweig/Wiesbaden 1987 Wave
  propagation and wireless transmission
• A.S. Tanenbaum Computernetzwerke, 4. Aufl.,
  Prentice Hall, 1998 Protocols, ISO/OSI,
  standards, fixed networks Principles

6
1. Motivation and Examples
7
Motivation

• Speech- and Data Communication location
  independent and mobile
• Ä New application areas, flexibility, improved
  workflows
• Requirements
• - Mobile end-devices
• - Radio transmission
• - Localization and signalization/management
• - Standards

- Application Concepts for mobile end-devices in
distributed systems - Control of heterogeneous,
dynamic infrastructures Mobile Computing
8
Application example Civil Engineering, Field
Service
Drafts, urgent modification
Large archives, Videoconferences
ATM
ISDN
Building of enterprise A (main office)
Building of enterprise A (branch office)
Architect
X.25 ISDN ATM
Selected drafts, Videoconferences
GSM
GSM
Construction supervisor
Material data, status data, dates
Building site
Building of enterprise B
9
WAP-Example Order processing

• Order book
• Status of bond transactions.
• Executed and deleted orders are indicated in the
  order book for some days more.
• Partial execution of some order is presented as
  one open and one executed partial order in the
  order book.
• Details to an order could be indicated via
  dial-up of correspondent Links.

10
Perspective Mobile Multimedia Systems
Local Resources, Error Protocols
Client
Maintenance technician
Product Data
LAN-Access
Main office Caching
Mobile Access
- very different performance and charges radio
networks versus fixed networks Software-technica
l, automatic adaptation to concrete system
environment Example Access to picture
data/compressed picture
data/graphics/text
11
Application Structure
Ethernet
Ethernet
DB
Distributed Database
E-Fax-Order
Branch office
Firm
xDSL
GSM
Application Resource Mobile
Station Communication path
Ethernet
Cache
ManagementDB-Access
Distributed Database
Client X
12
Traffic Telematics Systems
Content Provider
Main Office
Content Provider
ATM
Internet
GSM, RDS/TMC, DAB ...
GSM
Beam Radio, ISDN
GSM
GSM
Radio/Infrared
DAB Digital Audio Broadcast RDS/TMC Radio Data
System/ Traffic Message Channel
Infrastructure
13
Mobile Communication Networks Examples
GSM (Global System for Mobile Communications)
worldwide standard for digital, cellular Mobile
Radio Networks UMTS (Universal Mobile
Telecommunications System) European Standard for
future digital Mobile Radio Networks AMPS
(Advanced Mobile Phone System) analog Mobile
Radio Networks in USA DECT (Digital Enhanced
Cordless Telecommunications) European standard
for cordless phones TETRA (Terrestrial Trunked
Radio) European standard for circuit switched
radio networks ERMES (European Radio Message
System) European standard for radio paging
systems (Pager) 802.11 International standard
for Wireless Local Networks Bluetooth wireless
networking in close/local area Inmarsat
geostationary satellite systems Teledesic
planned satellite system on a non-geostationary
orbit
14
Mobile Communication Development
C
Mobile Phone Networks
EDGE
GPRS
Cordless Telephony
IMT2000/ UMTS
Packet Networks
Modacom
Mobitex
Circuit Switched Networks
Tetra
Iridium/ Globalstar
Satellite Networks
Inmarsat
Radio-LAN
Local Networks
IEEE 802.11/ Hiperlan
MBS
IR-LAN
2005
2000
1995
1990
15
Used Acronyms
CT2 Cordless Telephone 2. Generation HSCSD High
Speed Circuit Switched Data GPRS General Packet
Radio Service EDGE Enhanced Data Rates for GSM
Evolution IMT2000 International Mobile
Telecommunications by the year 2000 MBS Mobile
Broadband System
16
2. Mobile Communication
17
Principles

18
Mobile Communication
Tied to electro-magnetic radio transmission
radio transmission
orbital (satellite)
terrestrial
broadcast radio
equatorial orbit
beam radio
non-equatorial orbit
cellular
non-cellular

• Principles
• Propagation and reception of electro-magnetic
  waves
• Modulation methods and their properties
• Multiplex methods
• Satellite orbits/Sight- and overlap areas

19
Cellular Networks Principles
7-Cell-Cluster (repeat sample of the same
radio-channels)
Supply- (radius R) and interference areas (5 R)
20
Cellular Networks Principles
Cell structure Example
Reference cell
Cell in the interference area of the reference
cell
Further cells, whose channel distribution should
be known to the reference cell
21
Kinds of antennas directional sectored

• Energy is radiated in definite directions, for
  instance x-Direction
• So called main propagation directions, for
  instance Satellite Antennas
• Often also used in Mobile Radio Systems, such as
  GSM, for creation of sectored cells
• Seamless radio supply via partial/overlay of
  sectors

y
x
Directional Antenna
Sectored Antenna
22
Media Access Methods
23
Principles

• Multiplex
• Multiple-shift usage of the medium without
  interference
• 4 multiplex methods
• Space
• Time
• Frequency
• Code
• Media Access Methods
• controls user access to medium

24
SDMA (Space Division Multiple Access)

• based on SDM (Space Division Multiplexing, Space
  Multiplex)
• communication channel obtains definite Space for
  definite Time on the definite Frequency with
  definite Code
• Space Multiplex for instance in the Analog Phone
  Systems (for each participant one line) and for
  Broadcasting Stations
• Problem secure distance (interferences) between
  transmitting stations is required (using one
  frequency) and by pure Space Multiplex each
  communication channel would require an own
  transmitting station
• Space Multiplex is only reasonable in combination
  with other multiplex methods
• SDMA for instance by base station dedication to
  an end-device via Media Access Methods or
  respectively by segmentation of a Mobile Radio
  Network to several areas

25
SDMA Example
k1
k2
k3
k4
k5
k6
f1
s
SDMA finds selection
s secure distance
26
FDMA (Frequency Division Multiple Access)

• Based on FDM (Frequency Division Multiplexing,
  Frequency Multiplex)
• i.e. to transmission channels several frequencies
  are permanently assigned, for instance radio
  transmitting stations

k1
k2
k3
k4
k5
k6
f1
f4
FDMA finds selection
f2
f5
s
f3
f6
s secure distance
27
TDMA (Time Division Multiple Access)

• Based on TDM (Time Division Multiplexing, Time
  Multiplex)
• i.e. to transmission channels is the transmission
  medium is slot assigned for certain time, is
  often used in LANs
• Synchronization (timing, static or dynamic)
  between transmitting and receiving stations is
  required

k1
k2
k3
k4
k5
k6
TDMA finds selection
f1
28
Combination FDMA and TDMA, for instance GSM

• GSM uses combination of FDMA and TDMA for better
  use of narrow resources
• the used band width for each carrier is 200 kHz

f in MHz
960
downlink
25 MHz
935,2
915
200 kHz
45 MHz
uplink
25 MHz
890,2
t
29
CDMA (Code Division Multiple Access)

• based on CDM (Code Division Multiplexing, Code
  multiplex)
• i.e. to transmission channels the definite Code
  is assigned, this can be on the same Frequency
  for the same Time transmitted
• derivates from military area
• via development of cost-efficient VLSI components
• via spread spectrum techniques a good
  communication security and tiny fault sensitivity
• but exact synchronization is required, code of
  transmitting station must be known to receiving
  station, complex receivers for signal separation
  are required
• Noise should not be very high

30
CDMA
k1
k2
k3
k4
k5
k6
f1
CDMA decoded
31
CDMA illustrated by example

• The Principle of CDMA can be good illustrated by
  the example of some party
• communication partners stand closely to each
  other, each transmission station (Sender) is only
  so loud, that it does not interfere to neighbored
  groups
• transmission stations (Senders) use certain Codes
  (for instance, just other languages), they can be
  just separately received by other transmission
  stations
• receiving station (Listener) attunes to this
  language (Code), all other Senders are realizing
  this only as background noise
• if receiving station (Listener) cannot understand
  this language (Code), then it can just receive
  the data, but it cannot do anything with them
• if two communication partners would like to have
  some secure communication line, then they should
  simply use a secret language (Code)
• Potential Problems
• security distance is too tiny interferences
  (i.e. Polish und Czech)

32
CDMA-Example in the theory

• Sender A
• Sends Ad 1, Key Ak 010011 (set 0 -1, 1
  1)
• Transmit signal As Ad Ak (-1, 1, -1, -1, 1,
  1)
• Sender B
• sends Bd 0, Key Bk 110101 (set 0 -1, 1
  1)
• Transmit signal Bs Bd Bk (-1, -1, 1, -1, 1,
  -1)
• Both signals superpose additively in air
• Faults are ignored here (noises etc.)
• C As Bs (-2,0,0,-2,2,0)
• Receiver will listen to Sender A
• uses Key Ak bitwise (internal product)
• Ae C Ak 2 00 2 20 6
• Result is greater than 0, so sent bit was 1
• analog B
• Be C Bk -2 0 0 -2 -2 0 -6, also 0

33
Spread Spectrum Techniques

• Signal is spread by the Sender before the
  transmission (overblown)
• dP/df value corresponds with so called Power
  Density, Energy is constant (in the Figure the
  filled areas)
• Objective
• Increase of robustness against small band-width
  faults
• listening security power density of
  spread-spectrum signals can be lower than that of
  background noise

34
Spread Spectrum Techniques
t

• small band-width faults are spread by
  de-spreading in receiving station
• band-pass deletes redundant frequency parts

35
Mobile Radio Networks Overview
36
Development of Mobile Radio
General technological development in mobile
telephony
Satellite Systems (LEO)
UMTS
HSCSD GPRS EDGE
GSM Phase II
Digital cellular Networks...1800 Mhz
PCN GSM1800
Digital cellular Networks...900 Mhz
GSM900
Prognoses
Anal. cellular Networks...900 Mhz
Anal. cellular Networks...450 Mhz
Analog Networks...150Mhz
before 1970
1970
1980
2000
2005
1990
37
Correspondent data rates
(GEO)
Satellites (GEO)
38
Participant quantities in Mobile Radio
world-wide

• November 2002 1148 Mio. participants world-wide
  (1119 Mio. digital 29 Mio analog)

(Source http//www.emc-database.com)
1... Europe Western 4... Americas (thereof 15.4
Mio. analog) 2... Asia Pacific 5... USA/Canada
(thereof 5.4 Mio. analog) 3... Middle East 6...
Africa 7 Europe Eastern
39
Frequency Assignment
Circuit Switched Radio Mobile Phones Cordless
Phones Wireless LANs
TETRA
NMT
CT2
CT1
GSM900
CT1
GSM900
TETRA
380-400 410-430
453-457
864-868
885-887
890-915
930-932
935-960
450-470 (nationally different)
1GHz
500Mhz
463-467
TFTS (Pager, aircraft phones)
GSM1800
TFTS
GSM1800
DECT
UMTS
1670-1675
1710-1785
1800-1805
1805-1880
1880-1900
(1885-2025 2110-2200)
WLAN
IEEE 802.11a 5,15-5,25 5,25-5,35 5,725-5,825
IEEE 802.11b
HIPERLAN1
Bluetooth
HIPERLAN2
HIPER-Link
MHz
2400-2483
5176-5270
2402-2480
(ca.5200,5600)
(ca.17000)
2412-2472
Notes - 2,4 GHz license free, nationally
different - () written Prognoses! - today
speech over license free frequencies up to
61Ghz -gt interesting for high data rates
HomeRF...(approx.2400)
TFTS - Terrestrial Flight Telephone System
40
Broadcast/multicast networks

• several carrier frequencies but participant
  obtains carrier for short time only
• often in use by taxi- und logistics enterprises
  etc., each own separated frequency reaches
• can use the same frequency packs with FDM- and
  TDM- techniques, i.e. more efficient handling
  with narrow resource frequency spectrum
• improves transition to fixed network, speech- and
  data services
• not for public access
• very reliable, cost-efficient

41
TETRA (Terrestrial Trunked Radio)

• former name Trans-European Trunked Radio
• frequencies 380-390, 410-420 MHz Uplink
  390-400, 420-430 MHz Downlink
• bandwidth of each channel 25 kHz
• 1991 started by ETSI
• replace of national networks like MODACOM,
  MOBITEX or COGNITO
• Services
• Voice Data (VD)- Service Speech and Data,
  channel-oriented, uni-, multi- and broadcast
  possible
• Packet Data Optimized (PDO)- Service
  packet-oriented, improves connection-oriented or
  connectionless service, as well as point-to-point
  and point-to-multipoint communication
• carrier services with data rate up to 28,8 kbit/s
  unprotected 9,6 kbit/s - protected

42
TETRA, advantages compared with GSM, UMTS

• confirmed and/or non-confirmed Group Call
  (however its already possible with GSM today up
  to 16 participants)
• Group call
• listening is possible (so called open-channel
  mode)
• very reliable
• fast dialing approx. 300 ms (so called push to
  talk), GSM several seconds
• certain independence of infrastructure (so called
  direct mode between end-devices)
• cost-efficient, especially for limited user
  quantity, because of the large cells x 10 km
• also especially suitable for emergency teams
  (fire department, ambulance etc.)

43
Cordless Telephony - DECT (Digital Enhanced
Cordless Telecommunications)

• frequency reach 1880 - 1990 MHz
• other than GSM limited to short reaches (1km)
• in buildings particularly under 50m
• is not designed for use at high rates
• mobile phones with GSM and DECT are available in
  the market
• 120 full duplex channels
• TDD (Time Division Duplex) for directional
  separation with 10ms frame length
• frequency reach is divided into 10 carrier
  frequencies using FDMA
• each station 10mW averaged, max. 250mW of
  transmitting power, GSM radio phones transmit
  at 1 to 2W, fixed car phones up to 8W

44
DECT system architecture
D4
D3
D2
HDB
PA
PT
FT
Local Networks
VDB
PA
PT
D1
FT
Global Networks
Local Networks
FT.. Fixed Radio Termination PT.. Portable Radio
Termination PA... Portable Terminations HDB.. Ho
me Data Base VDB.. Visitor Data Base
45
DECT - Multiplex
Used Data
Used Data
CRC
Synchronization
Signalization
CRC
Secure marker
(Speech)
(Speech)
64 bit
8 bit
160 bit
48 bit
32 bit
160 bit
8 bit
0,417 ms
DECT-timeslot structure
Transmission reach of fixed part (downlink)
Transmission reach of mobile part (uplink)
carrier frequency 1
1 2 3 4 5 6 .... 11 12
1' 2' 3' 4' 5' 6' .... 11'
12'
carrier frequency 2
1728
1 2 3 4 5 6 .... 11 12
1' 2' 3' 4' 5' 6' .... 11'
12'
kHz
carrier frequency 10
1' 2' 3' 4' 5' 6' .... 11'
12'
1 2 3 4 5 6 .... 11 12
Transmission principle of DECT-system
Channel 1
Channel 2
Channel 12
Channel 1
Channel 2'
Channel 12'
. . .
. . .
fixed part to mobile part
mobile part to fixed part
Time duplex with 10 ms frame length
Structure of DECT-time multiplex frame
46
Pager systems overview

• Eurosignal
• to each participant 4 different audio signals
  using 4 diverse call numbers are assigned.
  Meaning must be agreed. Receiving stations are at
  a size of a cigarette packet
• 85 senders in the 87 MHz-reach (ultra short
  waves)
• called person location must be approximately
  known 3 area codes North 0509, Middle 0279,
  South 0709
• Cityruf (city call)
• additionally to 4 audio- or respectively optical
  signals transmission of short numerical (15
  digitals) or alpha-numerical messages (80
  characters) exists optionally, receiving station
  is smaller than with Eurosignal
• PEP (Pan European Paging)
• preparation for coupling of national services for
  ERMES
• D Cityruf, F Alphapage, GB Europage, I SIP
• ERMES (European Radio Message System)
• ETSI-Standard for pan-European radio service,
  similar to PEP but in 169 MHz-reach with 60 Mio.
  addresses

47
GSM Global System for Mobile Communications
48
GSM Properties

• cellular radio network (2nd Generation)
• digital transmission, data communication up to
  9600 Bit/s
• Roaming (mobility between different net
  operators, international)
• good transmission quality (error detection and
  -correction)
• scalable (large number of participants possible)
• Security mechanisms (authentication,
  authorization, encryption)
• good resource use (frequency and time division
  multiplexing)
• integration within ISDN and fixed network
• standard (ETSI, European Telecommunications
  Standards Institute)

49
Providers in Germany (1)

• D1 T-Mobile
• subscribers 24,6 Mio (Stand 2003)
• Vodafone D2
• old name Mannesmann Mobilfunk D2
• subscribers 22,7 Mio (Stand 2003)
• E-plus
• O2
• old name VIAG Interkom

50
Providers in Germany (2)
Providers Subscribers, millions Subscribers, millions Subscribers, millions Subscribers, millions
Providers 2001 2002 2003 World-wide by 2003
D1 T-Mobile 22,6 23,1 24,6 82
Vodafone D2 21,9 - 22,7 112,5
E-Plus - 7,5 - -
O2 VIAG Interkom - 3,66 - -
51
GSM structure
Fixed network
Switching Subsystems
Radio Subsystems
OMC
Data networks
VLR
HLR
AuC
EIR
(G)MSC
BTS
BSC
PSTN/ ISDN
BTS
BSS
MS
MS Mobile Station (G)MSC (Gateway) Mobile
Switching Centre OMC Operation and Maintenance
Centre PSTN Public Switched Telephone
Network VLR Visitor Location Register ISDN Integra
ted Services Digital Network
AuC Authentication Centre BSS Base Station
Subsystem BSC Base Station Controller BTS Base
Transceiver Station EIR Equipment Identity
Register HLR Home Location Register
52
GSM Structure

• Operation and Maintenance Centre (OMC)
• logical, central structure with HLR, AuC und EIR
• Authentication Centre (AuC)
• authentication, storage of symmetrical keys,
  generation of encryption keys
• Equipment Identity Register (EIR)
• storage of device attributes of allowed, faulty
  and jammed devices (white, grey, black list)
• Mobile Switching Centre (MSC)
• arrangement centre, partial as gateways to other
  nets, assigned to one VLR each
• Base Station Subsystem (BSS) technical radio
  centre
• Base Station Controller (BSC) control centre
• Base Transceiver Station (BTS) radio tower /
  antenna

53
Radio technical structure
1 TDMA-Frame, 144 Bit in 4,615 ms
8 TDMA-channels, together 271 kBit/s inclusive
error protection information
124 radio frequency channels (carrier), each 200
kHz
downlink
890
915 MHz
uplink
960 MHz
935
2 frequency wavebands, for each 25 MHz, divided
into radio cells

• One or several carrier frequencies per BSC
• Physical channels defined by number and position
  of time slots

54
GSM protocols, incoming call
(4)
(3)
VLR
HLR
BSS
(8)
(6)
(7)
(4)
(2)
(10)
(11)
(8)
(8)
(5)
(1)
(9)
(9)
MSC
GMSC
BSS
BSS
(12)
(12)
(8)
BSS
(1) Call from fixed network was switched via GMSC
(2) GMSC finds out HLR from phone number and
transmits need of conversation (3) HLR checks
whether participant for a corresponding service
is authorized and asks for MSRN at the
responsible VLR (4) MSRN will be returned to
GMSC, can now contact responsible MSC
55
GSM protocols, incoming call
(4)
(3)
VLR
HLR
BSS
(8)
(6)
(7)
(4)
(2)
(10)
(11)
(8)
(8)
(5)
(1)
(9)
(9)
MSC
GMSC
BSS
BSS
(12)
(12)
(8)
BSS
(5) GMSC transmits call to current MSC (6) ask
for the state of the mobile station (7)
Information whether end terminal is active (8)
Call to all cells of the Location Area (LA) (9)
Answer from end terminal (10 - 12) security check
and connection construction
56
GSM protocols, outgoing call
(1) Demand on connection (2) Transfer by
BSS (3-4) Control for authorization (5) Switching
of the call demand to fixed net
57
GSM channel strucure

• Traffic Channel
• speech- / data channel (13 kbit/s brutto
  differential encoding)
• units of 26 TDMA - Frames
• Half-rate traffic channel for more efficient
  speech encoding with 7 kbit/s
• Control Channel
• Signal information
• Monitoring of the BSCs for reconnaissance of
  Handover
• Broadcast Control Channel
• BSC to MS (identity, frequency order etc.)
• Random Access Channel
• Steering of channel entry with Aloha-procedure
• Paging Channel
• signalize incoming calls

58
Databases

• Home Location Register (HLR), stores data of
  participants, which are reported in an HLR-area
• Semi-permanent data
• Call number (Mobile Subscriber International ISDN
  Number) - MSISDN, e.g. 49/171/333 4444
  (country, net, call number)
• identity (International Mobile Subscriber
  Identity) - IMSI MCC Mobile Country Code (262
  for .de) MNC Mobile Network Code (01-D1,
  02-Vodafone-D2, 03-eplus, 07-O2) MSIN Mobile
  Subscriber Identification Number
• Personal data (name, address, mode of payment)
• Service profile ( call transfer, Roaming-limits
  etc.)
• Temporary data
• MSRN (Mobile Subscriber Roaming Number) (country,
  net, MSC)
• VLR-address, MSC-address
• Authentication Sets of AuC (RAND (128 Bit), SRES
  (128 Bit), KC (64Bit))
• charge data

59
Databases

• Visitor Location Register (VLR)
• local database of each MSC with following data
• IMSI, MSISDN
• service profile
• accounting information
• TMSI (Temporary Mobile Subscriber Identity) -
  pseudonym for data security
• MSRN
• LAI (Location Area Identity)
• MSC-address, HLR-address

60
GSM mobile telephone areas
MSC-area VLR-area
Handover
LA smallest addressable unit
61
Connection HLR, VLR
HLR
MSC-area
VLR
Location area
advantage of the architecture Location Update at
limited mobility, as a rule only at VLR, rarely
at (perhaps far remote) HLR
62
Localization at GSM
z.B.
0x62F220
01E5
LA 3
LA 2
LA 5
LA 3
63
Data transmission

• each GSM-channel configurable as a data channel
  similar structure like ISDN-B and -D-channels
• data rates up to 9600 bit/s now
• delay approximately 200 ms
• speech channels have as a rule higher priority as
  data channels
• kinds of channels
• transparent (without error correction however
  FEC fixed data rate error rate 10-3 up to 10-4)
  
• non-transparent (repeat of faulty data frames
  very low error rate, but also less throughput)
• Short-Message-Service (SMS)
• connectionless transmission (up to 160 Byte) on
  signal channel
• Cell Broadcast (CB)
• connectionless transmission (up to 80 Byte) on
  signal channel to all participants, e.g. one cell

64
Data transmission - structure
MSC
BSC
IWF
ISDN
UDI
BTS
Modem
TA
PSTN
Internet
Modem
IWF - Inter Working Function UDI - Unspecified
Digital TA - Terminal Adapter
65
Security aspects Subscriber Identity Module (SIM)

• Chip-card (Smart Cart) to personalize a mobile
  subscriber (MS)
• IMSI (International Mobile Subscriber Identity)
• participant special symmetric key Ki, stored also
  at AuC
• algorithm A3 for Challenge-Response-Authenticati
  on
• algorithm A8 for key generation of Kc for
  content data
• PIN (Personal Identification Number) for entry
  control
• Temporary data
• TMSI (Temporary Mobile Subscriber Identity)
• LAI (Location Area Identification)
• Encryption key Kc

66
Security in GSM-networks

• SIM
• Entry control and cryptographic algorithms
• Single-sided authentication (participant against
  network)
• Challenge-Response-method (cryptographic
  algorithm A3)
• Pseudonyms of participants at the Radio interface
• Temporary Mobile Subscriber Identity (TMSI)
• Connection encoding on the Radio interface
• Key generation A8
• Encryption A5

67
Security aspects Authentication
MS
MSC, VLR, AuC
max. 128 Bit

Random number generator
Authentication Request
A3
RAND (128 Bit)
A3
SRES
Authentication Response

SRES (32 Bit)

• Location Registration
• Location Update with VLR-change
• Call setup (in both directions)
• SMS (Short Message Service)

68
Security aspects Session Key
MS
Netz

Random numbergenerator
Authentication Request
A8
RAND (128 Bit)
64 Bit
A8

• Key generation Algorithm A8
• Stored on SIM and in AuC
• with Ki parametric one way function
• no (Europe, world wide) standard
• can be determined by net operator
• Interfaces are standardized
• combination A3/A8 known as COMP128

69
Security aspects encryption at the Radio
interface
Net
MS

Ciphering Mode Command
TDMA-frame-number
TDMA-frame-number
A5
A5
Key block
Ciphering Mode Complete
Plain text block
Encrypted Text
Plain text block
114 Bit

• Data encryption through algorithm A5
• stored in the Mobile Station
• standardized in Europe and world wide
• weaker algorithm A5 or A5/2 for specific
  countries

70
GSM-Security assessment

• cryptographic methods secret, so they are not
  well examined
• symmetric procedure
• consequence storage of user special secret keys
  with net operators required
• low key length Ki with max. 128 Bit (could be
  hacked by using Brute Force Attack in 8-12 hours)
• no mutual authentication intended
• consequence Attacker can pretend a GSM-Net
• no end-to-end encryption
• no end-to-end authentication
• Key generation and -administration not controlled
  by the participants

71
GSM Phase IIHSCSD, GPRS
72
HSCSD High Speed Circuit Switched Data
73
Properties

• higher data rate because of channel bundling
• parallel usage of several time slots (TCH) of one
  frequency on Um
• more efficient channel encoding (14,4 kbit/s per
  TCH)
• Data rates from 9,6 up to 53,8 kbit/s
• asymmetric transmission (1TCH Uplink /
• 3TCH Downlink)

74
HSCSD data rates
non transparent
transparent
up- / downlink
100 coverage
95 coverage
100 coverage
95 coverage
1 1
9,6
14,4
9,6
13,2
2 2
19,2
28,8
19,2
26,4
1 3
---
----
28,8
39,6
1 4
---
----
38,4
53,8
75
HSCSD structure
MSC
BSC
IWF
ISDN
UDI
BTS
Modem
TA
PSTN
n time slots (TCH) of each TDMA
frame (theoretically max. 8)
Internet
Modem
IWF - Inter Working Function UDI - Unspecified
Digital TA - Terminal Adapter
76
HSCSD changes
n time slots (TCH) of each TDMA
frame (theoretically max. 8)
MSC
BSC
BTS
Um
Abis
A
multiplex of the time slots on each 64
kBit/s channel
certain changes are necessary at the component
several changes at the software/firmware
minimal changes at the software/firmware
77
HSCSD radio interface
Required time for setting to transmission standby
Required time for setting to receiving standby
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
MS RECEIVE
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
5
MS TRANSMIT
MS MONITOR
Required time for signal strength measure and
setting to receiving standby

• parallel usage of several time slots limited to
  one frequency
• Cost factor limits number of used TCHs to (22)
  or (13, uplink, downlink)

78
Assessment of HSCSD

• existing net structure and accounting model
  maintained
• in comparison to GPRS only around1/5 of
  investment necessary
• HSCSD is still circuit switched
• has defined QoS- settings (data rate, delay)
• one logical channel will be switched on all
  interfaces for the time of the connection
• Non-efficient for burst-like traffic (Internet)
  or Flat Rate billing (Logistics)
• no international acceptance (Roaming!)
• uses also more resources on the radio interface
• problems with handover into a new cell

79
GPRS General Packet Radio Service
80
Properties

• Packet switching service (end- to- end)
• Data rates up to 171,2 kbit/s (theoretical)
• Effective and flexible administration of the
  radio interface
• adaptive channel encoding
• Internetworking with IP- and X.25 nets
  standardized
• dynamic sharing of resources with classical
  GSM speech services
• Advantage Billing and Accounting according to
  data volume
• Disadvantage cost intensive additional net
  hardware necessary

81
Properties

• point-to-point-Packet transfer service
• PTP-CONS (PTP Connection oriented Network
  Service)
• connection oriented, similar to X.25
• PTP- CLNS (PTP Connectionless Network Service)
• connectionless, similar to IP
• point- to- multipoint - group communication

82
GPRS Structure
GSM
MSC
BSC
HLR
BTS
Internet
Border Gateway
SGSN
GGSN
GGSN
other packet switching networks
GPRS BackboneFrame Relay / ATM
83
GPRS Changes
GMSC
public remote fixed nets
n time slots (TCH) per TDMA frame (theoretically
max. 8) per packet!
Circuit switched traffic
MSC
MAP
A
HLR/AuC GPRS register
Abis
BSC
BTS
Gs
PCU
MAP
Gb
SGSN
Packet arranged traffic
Um
Gn
Gi
GGSN
PCU - Packet Control Unit
84
Tasks SGSN, GGSN

SGSN - mobility management - session
management - QoS - security
External Data Domain
HLR
MAP Signalization (GGSN)
MAP Signalization (SGSN)
SGSN
Internet
Intranet
BSS PCU
GGSN
BSS PCU
Client
SGSN
BSS PCU
SGSN, GGSN - Routing - Signalization - Resource
management
Client
Server
85
Tasks of the SGSN

• Packet delivery
• mobility management
• apply/ sign off of terminals
• localization
• LLC (Logical Link Control) management
• authentication
• billing

86
Tasks of the GGSN

• mediator between GPRS backbone and external data
  networks (Internet, X-25 etc.)
• converts GPRS packets, data Protocol (PDP) into
  the corresponding structure
• also converts PDP addresses of incoming packets
  into GSM address of the receiver
• saves current data for the SGSN address of the
  participant as well as their profile and data for
  authentication and invoice

87
GPRS air interface

• Radio Link Control (RLC)
• Segmentation of the LLC-Frames in RLC blocks
• Block size dependent on short-term channel
  conditions
• Backward error correction and data flow control
  by Automatic Repeat Request (ARQ) protocol
• repeating not repairable RLC blocks selectively
• Medium Access Control ( MAC)
• Channel reservation contains - one/several
  time slots (Packet Data Channels PDCH) of one
  frequency
• one uplink status flag (USF) per Packet Data
  Channel (PDCH), channel partition of up to 8 ms

88
GPRS air interface

• Medium Access Control ( MAC)
• Reservation in the uplink (MS to BSS)
• MS sends reservation request on a Random Access
  Channel (Slotted ALOHA)
• BTS allocates a (split) channel and sends packet
  assignment
• MS sends data depending on the current priority
  (USF flag)
• Reservation in the Downlink (BSS to MS)
• BTS displays transmitting request and informs
  about the reserved channel
• MS supervises the reserved channel and receives

89
GPRS air interface

• Physical Link Control
• adaptive forward error correction (FEC) dependent
  on short-term channel conditions
• temporal scrambling (Interleaving) of the bursts
  and Mapping on reserved PDCH (Packet Data
  Channel)
• procedure to recognize overbooking situations on
  the physical channel

GPRS Channel Encoding
90
Quality of Service

• QoS profile agrees service parameters inside the
  whole network
• Agreed for the duration of one PDP (Packet Data
  Protocol) context (session, end terminal is
  obtainable for the duration of the context, e.g.
  obtainable over Internet )
• temporary address (IP) for mobile station
• tunneling information, among others GGSN, which
  is used for access to corresponding packet
  arranged network
• type of the connection
• QoS profile
• QoS profile commits
• precedence class, priority against other services
  (high, normal, low)
• packet delay class, times are valid for traffic
  inside the GPRS- network
• reliability class
• peak throughput class
• mean throughput class

91
Quality of Service
Packet delay classes
Security classes
92
Quality of Service
GPRS- using data rates

• CS 3 and CS 4 are only reasonable in the second
  phase of GPRS introduction
• They will be used adaptively at corresponding
  good quality of radio connection
• CS 4 does not comprise error correction, code
  rate 1!

93
Assessment of GPRS

• An up to 4 times higher data rate in comparison
  to ordinary GSM- data services
• better resource management through packet
  arranged service
• always on data service (email, etc.)
• GPRS is a more suitable carrier for services like
  WAP
• - IP-derivate, no true guaranties (QoS)
• - development of the network infrastructure is
  relatively expensive, particularly regarding
  introduction to UMTS (return of investment)
• - GPRS doesnt give such data rates like
  advertising has sometimes promised

94
Development of the GSM-data services
Data rate
CS 1
CS 2
39.6 kbit/s
40.2 kbit/s
27.2 kbit/s
HSCSD Channel packing, NT
26.4 kbit/s
26.8 kbit/s
GPRS Packet arranged
18.1 kbit/s
13.2 kbit/s
13.4 kbit/s
9.6 kbit/s
9 kbit/s
flow
95
Enhanced Services - EMS (enhanced message service)

• Uses widespread existing infrastructure (SMS)
• new Mobile telephones necessary
• allows sending and receiving of messages with
  formatted texts, melodies, graphics (32 x 32
  Pixel) and animations (16 x 16 Pixel) e.g.
  NOKIA
• new applications like Mobile Ticketing
• tickets will be transferred to mobile phone like
  a bar code and checked at the admission
• EMS enables transition to MMS (multimedia
  messaging service), which allows transmission of
  multimedia enriched messages over UMTS-Network
  (photos, parts of videos)
• MMS requires new network elements in the
  Infrastructure of the operators

96
MMS - architecture
MMS User Databases
HLR
MMS Relay
LDAP
GSM-MAP or IS-41-MAP or TCP/IP
WAP or MExE (e.g. Java and TCP/IP)
MMS User Agent
SMTP, HTTP, POP3, IMAPv4
SMTP
alien MMS Relay
. . .
MMS Server (e.g. E-Mail)
MMS Server (other service)
MMS Server (e.g. Fax)
Based on materials from 3GPP, http//www.3gpp.org
97
UMTSUniversal Mobile Telecommunications System,
3G,3rd generation of mobile radio
98
IMT-2000 - structure

• 3 systems - UMTS - CDMA2000 - UWC-136
• 2 core technologies - TDMA - CDMA

individual carrier
IMT-SC
UWC-136 (EDGE)
TDMA
multiple carrier
IMT-FT
DECT
IMT-2000
UTRA-FDD
IMT-DS
FDD
IMT-MC
CDMA2000
CDMA

• IMT-2000 family of radio interfaces
• IMT-DS (Direct Spread)
• UTRA-FDD (UMTS)
• IMT-MC (Multi Carrier)
• CDMA2000, USA
• IMT-TC (Time Code)
• UTRA-TDD (UMTS), TD- SCDMA (Synchronous Code
  Division Multiple Access, China)
• IMT-SC (Single Carrier)
• UWC-136, USA
• IMT-FT (Frequency time)
• DECT

UTRA-TDD
TDD
IMT-TC
TD-SCDMA
satellite- supported network expansion-
SW-CDMA Satellite Wideband CMDA - SW-CDTMA
Satellite Wideband CDMA/TDMA (Hybride
procedure) - SAT-CDMA Satellite CDMA - ICO
RTT ICO Radio Transmission Technology
In europeUMTS
ICO RTT... Standard by ICO Global
CommunicationsIMT ... International Mobile
TelecommunicationsUTRA ... Universal Terrestrial
Radio AccessUWC ... Universal Wireless
Communications
source www.UMTS-Report.com
99
Worldwide frequency assignment for IMT-200

• developed by ITU

PCS... Personal Communication SystemMSS...Mobile
Satellite ServicePHS... Personal Handy-Phone
System
100
UMTS - Facts

• consideration early 90ies
• Universal Mobile Telecommunications System,
  developed in the EU (ETSI European
  Telecommunication Standards Institute)
• UMTS is the European implementation of IMT-2000
  (International Mobile Telecommunications by the
  year 2000)
• Start of network expansion
• in Europe 2003 (some trials, e.g. British
  Telecom on Isle of Man, 2002)
• in the USA 2005
• in Japan since 2000 NTT DOCOMO

101
Frequency award in Europe
230 MHz frequency range for IMT-2000
MSS
MSS
GSM1800 Downlink
GSM1800 Uplink
FDD Uplink
FDD Downlink
DECT
TDD
TDD
1700 1750 1800 1850 1900 1950
2000 2050 2100 2150 2200
MSSSatellite- based

• at FDD symmetrical spectrum is necessary, not at
  TDD (time slots at same frequency)
• gradual new assignment of wavebands
• depending on development of the need up to
  300-500 MHz frequency range in 2008

source www.UMTS-Report.com
102
Characteristics

• system general , worldwide roaming
• high data rates 144 kbit/s mobile, up to 2
  Mbit/s at local area
• fusion of different mobile radio communications-,
  wireless- and pager-systems into one common
  system
• speech-, data-, and multimedia- information
  services independent of used network access
• support of different carrier services
• real-time capable/not real-time capable
• circuit switched/ packet switched
• Roaming also between UMTS and GSM and satellite
  networks
• Asymmetrical data rates in up-/downlink

103
UMTS- Disadvantages

• Technology not yet perfect
• rent ability of pico cells (Hotspots) not yet
  analyzed
• strong contention by WLAN
• increased radiation exposure
• high data rate only obtainable sometimes
  (High-Tech-network expansion, stationary and
  exclusive usage necessary!)
• because of high license costs high charges
  necessary (around double GSM-costs)

104
UMTS - Performance
Transmission Real- time (Video) Not Real-time (SMS etc.)
Bit error rate 10-3 10-7 10-5 10-8
Permitted delay 20ms 300ms gt 150 ms
Photo
Video
Report
UMTS
Web
Photo
Video
Report
GPRS
Web
Photo
Mail
Video
Report
ISDN
Web
Photo
Mail
PSTN
Web
Photo
Mail
Report
Video
GSM
0 sec
10 sec
1 min
10 min
1 h
source Mobilkom Austria
105
UMTS - Hardware

• big color displays
• high resolution
• True Color

106
UMTS- cell structure
Internet
UMTS-Core Network
HomeLocationRegister
GatewayGPRSSupportNode
GatewayMobileSwitchingCentre
circuitswitched
customerIntranet
PSTN/ISDN
3G- ServingGPRSSupportNode
3GMobileSwitchingCentre
VisitorLocationRegister
packet-switched
Base Station Controller
Radio Network Controller
Radio Network Controller
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
Radioaccessnetwork
GSM - BSS
UTRAN- UMTS Terrestrial Radio Access Network
Quelle Mobilkom Austria
107
UMTS cell structure
Satellite
Zone 4 Global
World cell
Zone 3 Suburban
Zone 2 Neighborhood
Macro cell
Zone1 In-building
Micro cell
Pico cell
108
UMTS hierarchical cell structure
principle - all neighbor cells use same
frequency channel- only one waveband is
necessary for cellular construction- further
wavebands are necessary for hierarchical structure
Global
Regional
Lokal
Home/ Office
Pico
Micro
World
Macro
expansion Data rate (kbit/s) Max. velocity (mph) Special features
World Cell global - no UTRAN, other technology!
Macro Cell Up to 1,24 miles 144 310 complete national UMTS support
Micro Cell Up to 0,62 miles 384 74 Greater cities, commonly used
Pico Cell gt 60miles 2000 6,2! Hotspots e.g. airport, station
109
Classification
110
Service concept

• Virtual Home Environment (VHE) offered services
  are freely configurable, configuration still
  exists in the whole network
• choose of service quality and also arising costs
• behave at bottlenecks (data rates, etc.)
  configurable
• dynamic customization to connection

111
UPT Universal Personal Telecommunication Service

• one phone number for several devices (Call-
  Management)
• subscriber localization e.g. with SIM-card
• call passing
• virtual mobility of fixed networks

112
Intelligent networks

• Implementation of basic services like subscriber
  localization billing etc.
• supply of value added service (Voice-Mailbox,
  etc.)
• possibility of easy, fast introduction of new
  services
• flexible service administration
• usage of services also from foreign network
  possible
• better control of service parameters through
  subscriber

113
UMTS basic network structure

• Access Network base stations, responsible for
  radio contact to mobile end devices
  
• Core Network (Fixed Network) responsible for
  structure of connections
• Intelligent Network (IN) responsible for
  billing, subscriber localization, Roaming,
  Handover

Intelligent Network
Core Network
Access Network
User Equipment (UE)
114
General reference architecture

• UTRA UMTS Terrestrial Radio Access
• UTRAN (UTRA- Network) contains several radio
  subsystems, so called Radio Network Subsystems
  (RNS) and contains functions for mobility
  management
• RNS controls handover at cell change, capacitates
  functions for the encoding and administrates the
  resources of the radio interface
• Uu connects UTRAN with mobile end devices, so
  called User Equipment (UE), is comparable with Um
  in GSM
• UTRAN is connected over Iu with the Core Network,
  comparable with the A interface in GSM between
  BSC and MSC
• CN contains the interfaces to other networks and
  mechanisms for connection handover to other
  systems

115
The UMTS-radio interface UTRA (UMTS Terrestrial
Radio Access)

• Two modes defined
• UTRA/FDD (Frequency Division Duplex)
• mainly in suburban areas for symmetrical
  transmission of speech and video
• data rates up to 384 kbit/s, supra-regional
  roaming
• for circuit- and packet switched services in
  urban areas
• UTRA/TDD (Time Division Duplex)
• mainly in households and other restricted areas
  (company's premises, similar to DECT)
• for broadcast of speech and video, both
  symmetrical up to 384 kbit/s
• also asymmetricalup to 2 Mbit/s

116
UTRA/FDD

• puts wide- band- CDMA (W-CDMA) together with DSSS
  (Direct Sequence Spread Spectrum) as spread
  spectrum technique
• channel separation by carrier frequencies,
  spreading code and phase position (only uplink)
• ca. 250 channels for used data, data rates up to
  2 Mbit/s
• complex performance control necessary

117
UTRA/TDD

• puts wideband- TDMA/CDMA together with DSSS
• sends and receives on same carrier (TDD)
• ca. 120 channels for used data, data rates up to
  2 Mbit/s
• channel separation by spread code and time slots
• less spreading than at FDD
• precise synchronization necessary
• lower demand for performance control

118
Frequency award for UMTS
Extension Bands (for a future market potential
..from 2005)
Extension Band 1 (worldwide similar) partly
terrestrial, partly satellite- based
119
UMTS-licenses in Germany

• E-Plus Hutchison
• 8.394.492.363
• Group 3G
• 8.408.706.278
• Vodafone (Mannesmann Mobilfunk)8.422.920.192
• MobilCom Multimedia
• 8.369.848.095
• T-Mobil
• 8.478.344.232
• O2 (VIAG Interkom)
• 8.445.008.001
• 17.08.2000 each license got 2 x 5 MHz packets,
  60 MHz have been given away altogether, 150 MHz
  are available altogether

RegTP determined - till end of 2003 25 network
coverage - till end of 2005 50 network coverage
120
Summary

• introduced variants are the proposals, which will
  be supported by Europe, Japan and partly by the
  USA
• worldwide accessibility can be realized only with
  multimode end devices
• even in Europe combined UTRA-FDD/UTRA-TDD/GSM-
  devices are necessary (those are realized by the
  identical frame time of 10ms at relatively low
  costs)

121
Wireless Local Networks, WLAN

122
Why do we need wireless LANs?

• Advantages
• flexibility
• Ad-hoc-network realizable with less expenditure
• No problems with cables
• Disadvantages
• high error vulnerability on the transmission link
  in comparison to Standard-LANs
• National restrictions, no international standards
  at used frequency bands (Industrial Scientific
  Medical (ISM)- Band)
• security, costs

123
Application areas

• networks in exhibition halls
• hospitals
• warehouses
• airports
• structure of networks in historic buildings
• extension of existing wired local area networks
  in offices, universities etc.

124
Problems with the use of WLANs

• physical problems
• interference band spreading
• echo use of special antennas
• Hidden Terminal problem use CSMA/CA
• data security
• Wired Equivalent Privacy (WEP) service
• further development WiFi (Wireless
  Fidelity), WPA (WiFi Protected Access)

125
Standards

• IEEE 802.11 (a,b,g optional e,h,i)
• frequency band 2,4 GHz, also in the 5GHz - band
• data rates 1 bis 11 Mbit/s (at present, later up
  to 20 (2,4 GHz) or 54 Mbit/s (5,4 GHz))
• WiFi Wireless Fidelity, certificate from the
  WECA (Wireless Compatibility Allicance), secures
  the interoperability between the Radio- LANs and
  contains improved security mechanisms
• HomeRF
• Bluetooth (IEEE 802.15)
• Frequency band 2,4 GHz
• Data rate 1 Mbit/s in the future also 20 Mbit/s
• connection of peripherals
• HIPERLAN (ETSI) / Wireless ATM
• frequency bands 5,15 / 5,30 GHz and 17,1 / 17,3
  GHz
• data rates 24 Mbit/s or 155 Mbit/s
• however no practical relevance

126
IEEE 802.11b

• frequency
• 2,4 GHz frequency band, also called ISM (
  Industrial Scientific Medical Band), not
  regulated
• 850 - 950 nm at infrared
• transmission power
• min. 1mW
• max. 100mW in Europe (1W in the USA)
• reach
• of 10m (IR) to 30km or more with the help of
  special antennas (directional antennas)

127
Basic WLAN- structure
Ad-hoc-network
3 connected infrastructure networks
AP - Access Point
128
System architecture IEEE 802.11
802.x LAN
802.11 LAN
STA1
ESS
BSS1
Access Point
Portal
Distribution System
Access Point
BSS2
STA2
STA3
802.11 LAN
129
System architecture IEEE 802.11, concepts

• Station (STA)
• device with 802.11- concurring interface
• Access Point
• allows the access to the distribution system for
  registered stations and secures accessibility of
  the stations also beyond the BSS
• Coordination Function (CF)
• logical functional unit, which decides when a
  station can send
• Basic Service Set (BSS)
• consists of several stations, that were
  controlled by an CF, e.g. BSS2 and STA2, STA3

130
System architecture IEEE 802.11, concepts

• Distribution System
• connects several BSS over access points and forms
  a logically larger net
• Extended Service Set (ESS)
• Radio networks, which are connected over
  Distribution System
• Portal
• allows transition into other networks

131
Overview

• 802.11 is the most frequently used solution for
  wireless connection very strong distribution on
  the market
• interesting future option Seamless Handover
  between GSM and IEEE 802.11 supported by Cisco,
  Intel etc. (alternative to UMTS?)
• higher data rates already standardized or in use
• 802.11a physical layer at 5 GHz  Band, data
  rates up to 54 MBit/s
• 802.11b extension to physical layer for the 2,4
  GHz  band, data rates up to 11 MBit/s, products
  available
• 802.11g at present the industry works on an
  extension, shall allow the up to 54Mbit/s in the
  frequency band around 2.4 GHz
• Study Group 5GSG examines the harmonization
  between IEEE 802.11 and ETSI HiperLAN
• Task Group e MAC functions for QoS-Management
  and to refine improved safety functions,
  introduction of service classes etc.

132
802.11 Norms for WLAN
802.11 Since end of 1990 RadioLAN B1-2 MBit/s ISM-Band F2,4GHz low Interoperability and bit rate!
802.11b 11MBit/s, actual Standard, existed NICs and APs ISM-Band F2,4GHz possesses further sub-standards
802.11a Since 2000 competition with 802.11b up to 54 MBit/s F5,1 GHz, correspond. national restrictions in the buildings
802.11g Ratification March, 2003 first pre-standard products ISM-Band 2,4GHz up to 54 MBit/s
802.11e Sub-standard planed for end 2003 use of QoS-approaches realization of multimedia applications/ Voice over IP over WLAN
802.11h Sub-standard / method for 802.11a optional functionality transmission power control of radio interface by national via RegTP prescribed norms correspond. especially for Germany 802.11a or h
802.11i Sub-standard security approaches for WLAN (encryption, authentication)
WPA WiFi Protected Access Substandard competition with 802.11i
802.11c Sub-standard Method of Wireless-Bridging
802.11d Sub-standard country specifics for 802.11b
802.11f Sub-standard Routing between radio cells of different vendors by IAPP (Inter-Access-Point Protocol)
133
Parameters Standards 802.11 Standards 802.11 Standards 802.11 Standards 802.11
Parameters 802.11 802.11b 802.11a / h 802.11g
Frequency band, GHz 2,4 (ISM-Band) 2,4 (ISM-Band) 5,1 2,4 (ISM-Band)
Bit rate, MBit/s 1-11 11 54 54
Use field building, territory building, territory in the buildings building, territory
Deployment End 1990 actually Since 2000 Since March 2003
Available Hardware Marketable NICs and APs Marketable NICs and APs Experimental operation Pre-standard