course on wireless 05
TRANSCRIPT
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Wireless Networking TechnologiesWLAN, WiFi Mesh and WiMAX
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Wireless Networks
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Wireless networks
Access co/uting3counication ser&ices, on the o&e
Wireless WANs Cellular Networks4 5'M, 56#', CDMA
'atellite Networks4 7ridiu
Wireless LANs WiFi Networks4 *+-..
6ersonal Area Networks4 $luetooth
Wireless MANs WiMaX Networks4 *+-.2
Mesh Networks4 Multi8ho/ WiFi
Adhoc Networks4 useful when infrastructure not a&aila!le
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Liitations of the o!ile en&ironent
Liitations of the WirelessNetwork liited counication !andwidth fre%uent disconnections
heterogeneit" of fragented networks
Liitations 7/osed !" Mo!ilit" route !reakages
lack of o!ilit" awareness !" s"ste3a//lications
Liitations of the Mo!ile De&ice short !atter" lifetie
liited ca/acities
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Mo!ile counication
Wireless &s- o!ile 9:a/les
stationar" co/uter la/to/ in a hotel (/orta!le) wireless LAN in historic !uildings 6ersonal Digital Assistant (6DA)
7ntegration of wireless into e:isting fi:ed networks4 Local area networks4 7999 *+-.., 9T'7 (;769#LAN)
Wide area networks4 Cellular
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Wireless &3s Wired networks
#egulations of fre%uencies Liited a&aila!ilit", coordination is re%uired
useful fre%uencies are alost all occu/ied
$andwidth and dela"s Low transission rates
= few >!its3s to soe M!it3s-
;igher dela"s
= se&eral hundred illiseconds
;igher loss rates
= susce/ti!le to interference, e-g-, engines, lightning Alwa"s shared ediu
Lower securit", si/ler acti&e attacking
radio interface accessi!le for e&er"one
secure access echaniss i/ortant
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!/s
@2 >!/s
@? M!/s
M!/s
@8.. M!/s
.8 M!/s *+-..
Wireless Technolog" Landsca/e
$luetooth
*+-..!
*+-..Ba,!
Tur!o -..a
7ndoor
.+
Long rangeoutdoor
@> +>
Long distanceco-
+ @+>
wave p-to-p links
-.. /8to8/ link
5
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#eference odel
A//lication
Trans/ort
Network
Data Link
6h"sical
Mediu
Data Link
6h"sical
A//lication
Trans/ort
Network
Data Link
6h"sical
Data Link
6h"sical
Network Network
#adio
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9ffect of o!ilit" on /rotocol stack
A//lication new a//lications and ada/tations
ser&ice location, ultiedia
Trans/ort congestion and flow control
%ualit" of ser&ice
Network addressing and routing
de&ice location, hand8o&er
Link edia access and securit"
6h"sical transission errors and interference
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6ers/ecti&es
Network designers4 Concerned with cost8effecti&edesign Need to ensure that network resources are efficientl" utiliEed
and fairl" allocated to different users-
Network users4 Concerned with a//lication ser&ices Need guarantees that each essage sent will !e deli&ered
without error within a certain aount of tie-
Network /ro&iders4 Concerned with s"steadinistration Need echaniss for securit", anageent, fault8tolerance
and accounting-
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#F $asics
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Factors affecting wireless s"ste design
Fre%uenc" allocations What range to o/erate Ma" need licenses-
Multi/le access echanis ;ow do users share the ediu without interfering
Antennas and /ro/agation What distances 6ossi!le channel errors introduced-
'ignals encoding
;ow to i/ro&e the data rate 9rror correction
;ow to ensure that !andwidth is not wasted
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Fre%uencies for counication
0LF G 0er" Low Fre%uenc" H;F G Hltra ;igh Fre%uenc" LF G Low Fre%uenc" ';F G 'u/er ;igh Fre%uenc" MF G Mediu Fre%uenc" 9;F G 9:tra ;igh Fre%uenc" ;F G ;igh Fre%uenc" H0 G Hltra&iolet Light
0;F G 0er" ;igh Fre%uenc"
Fre%uenc" and wa&e length4 G c3f wa&e length , s/eed of light c
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Wireless fre%uenc" allocation
#adio fre%uencies range fro >;E to ?++5;I (7TH)
Microwa&e fre%uenc" range . 5;E to ?+ 5;E
Directional !eas /ossi!le
'uita!le for /oint8to8/oint transission Hsed for satellite counications
#adio fre%uenc" range
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Fre%uencies for o!ile counication
0;F83H;F8ranges for o!ile radio si/le, sall antenna for cars
deterinistic /ro/agation characteristics, relia!le connections
';F and higher for directed radio links, satellitecounication
sall antenna, focusing
large !andwidth a&aila!le
Wireless LANs use fre%uencies in H;F to ';F s/ectru soe s"stes /lanned u/ to 9;F
liitations due to a!sor/tion !" water and o:"gen olecules(resonance fre%uencies)
= weather de/endent fading, signal loss caused !" hea&"rainfall etc-
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Fre%uenc" regulations
Fre%uencies fro >;E to
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Wireless transission
Wireless counication s"stes consist of4 Transitters
Antennas4 radiates electroagnetic energ" into air
#ecei&ers 7n soe cases, transitters and recei&ers are
on sae de&ice, called transcei&ers-
Transmitter Receiver
ntennantenna
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Transitters
m!"i#ier
$sci""ator
%i&er 'i"ter m!"i#ier
ntenna
Transmitter
S(!!ose yo( )ant to *enerate a si*na" that is sent at 900 %+, andthe ori*ina" so(rce *enerates a si*na" at 300 %+,-
.m!"i#ier / stren*thens the initia" si*na"
.$sci""ator / creates a carrier )ave o# 600 %+,
.%i&er / combines si*na" )ith osci""ator and !rod(ces 900 %+,a"so does mod("ation etc.'i"ter / se"ects correct #re(ency.m!"i#ier / Stren*thens the si*na" be#ore sendin* it
So(rce
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Antennas
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Antennas
An antenna is an electrical conductor or s"ste of
conductors to send3recei&e #F signals Transission 8 radiates electroagnetic energ" into s/ace
#ece/tion 8 collects electroagnetic energ" fro s/ace
7n two8wa" counication, the sae antenna can !e
used for transission and rece/tion
$mnidirectiona" ntenna
"o)er #re(ency
irectiona" ntenna
hi*her #re(ency
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#adiation and rece/tion of electroagnetic wa&es,
cou/ling of wires to s/ace for radio transission 7sotro/ic radiator4 e%ual radiation in all directions
(three diensional) 8 onl" a theoretical referenceantenna
#eal antennas alwa"s ha&e directi&e effects(&erticall" and3or horiEontall")
#adiation /attern4 easureent of radiation aroundan antenna
Antennas4 isotro/ic radiator
E"
:
E
" : idealisotro/icradiator
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Antennas4 directed and sectoriEed
side &iew (:"8/lane)
:
"
side &iew ("E8/lane)
E
"
to/ &iew (:E8/lane)
:
E
to/ &iew, < sector
:
E
to/ &iew, 2 sector
:
E
Often used for icrowa&e connections or !ase stations
for o!ile /hones (e-g-, radio co&erage of a &alle")
directedantenna
sectoriEedantenna
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Antenna odels
In OmniMode:
Nodes recei&e signals with gain Go
In DirectionalMode:
Ca/a!le of !eaforing in s/ecified direction Directional 5ain Gd (Gd > Go)
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Directional counication
#ecei&ed 6ower (Transit /ower)
J(T: 5ain) J (#: 5ain)
Directional gain is higher
Directional antennas useful for47ncrease Krange, kee/ing transit /ower constant#educe transit /ower, kee/ing range co/ara!lewith oni ode
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Co/arison of oni and directional
7ssues Oni Directional
'/atial #euse Low ;igh
Connecti&it" Low ;igh
7nterference Oni Directional
Cost Co/le:it" Low ;igh
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Antennas4 di&ersit"
5rou/ing of or ore antennas
ulti8eleent antenna arra"s
Antenna di&ersit" switched di&ersit", selection di&ersit"
= recei&er chooses antenna with largest out/ut
di&ersit" co!ining= co!ine out/ut /ower to /roduce gain
= co/hasing needed to a&oid cancellation
3?33?
ground /lane
33
3
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'ignal 6ro/agation and Modulation
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'ignals
/h"sical re/resentation of data
function of tie and location signal /araeters4 /araeters re/resenting the &alue of
data classification
continuous tie3discrete tie continuous &alues3discrete &alues
analog signal G continuous tie and continuous &alues
digital signal G discrete tie and discrete &alues
signal /araeters of /eriodic signals4
/eriod T, fre%uenc" fG.3T, a/litude A, /hase shift sine wa&e as s/ecial /eriodic signal for a carrier4
s(t) G Atsin( ft t t)
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Attenuation4 6ro/agation #ange
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Attenuation
'trength of signal falls off with distance o&ertransission ediu
Attenuation factors for unguided edia4
#ecei&ed signal ust ha&e sufficient strength so thatcircuitr" in the recei&er can inter/ret the signal
'ignal ust aintain a le&el sufficientl" higher thannoise to !e recei&ed without error
Attenuation is greater at higher fre%uencies, causingdistortion
A//roach4 a/lifiers that strengthen higherfre%uencies
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'ignal can take an" different /aths !etween sender and recei&er due toreflection, scattering, diffraction
Tie dis/ersion4 signal is dis/ersed o&er tie interference with Kneigh!or s"!ols, 7nter '"!ol 7nterference (7'7)
The signal reaches a recei&er directl" and /hase shifted distorted signal de/ending on the /hases of the different /arts
Multi/ath /ro/agation
signal at sender
signal at recei&er
LO' /ulsesulti/ath/ulses
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9ffects of o!ilit"
Channel characteristics change o&er tie and location signal /aths change
different dela" &ariations of different signal /arts
different /hases of signal /arts
%uick changes in the /ower recei&ed
(short ter fading)
Additional changes in
distance to sender o!stacles further awa"
slow changes in the a&erage /owerrecei&ed (long ter fading)
short ter fading
long terfading
t
/ower
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6ro/agation odes
arth
arth
arth
a ro(nd ave ro!a*ation
b Sy ave ro!a*ation
c :ine/o#/Si*ht ro!a*ation
Transmission
ntenna
Receivin*
ntenna
Si*na"
Si*na"
Ionos!here
Si*na"
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Modulation and deodulation
s"nchroniEationdecision
digitaldataanalog
deodulation
radiocarrier
analog!ase!andsignal
.+..+.++. radio receiver
digitalodulation
digitaldata analog
odulation
radiocarrier
analog
!ase!andsignal
.+..+.++. radio transmitter
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Digital odulation Modulation of digital signals known as 'hift >e"ing A/litude 'hift >e"ing (A'>)4
&er" si/le
low !andwidth re%uireents
&er" susce/ti!le to interference
Fre%uenc" 'hift >e"ing (F'>)4 needs larger !andwidth
6hase 'hift >e"ing (6'>)4 ore co/le:
ro!ust against interference
Man" ad&anced &ariants
. + .
t
. + .
t
. + .
t
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Multi/le:ing Mechaniss
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Multi/le:ing in ? diensions s/ace (si)
tie (t)
fre%uenc" (f)
code (c)
5oal4 ulti/le use
of a shared ediu
7/ortant4 guard s/aces neededP
s
s
(acknowledgeent) aftertransitting each frae kee/sco/" of last frae-
#ecei&er sends AC> if recei&ed
frae is error free- 'ender retransits frae if
AC>not recei&ed !efore tiere:/ires-
'i/le to i/leent !ut a"waste !andwidth-
9fficient 0ersion4 'liding Window
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$andwidth and Dela"
$andwidth
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$andwidth
Aount of data that can !e transitted /er unit tie e:/ressed in c"cles /er second, or ;ertE (;E) for analog
de&ices
e:/ressed in !its /er second (!/s) for digital de&ices
>$ G U.+ !"tes M!/s G .+U2 !/s
Link &3s 9nd8to89nd
$andwidth &3s !it width
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$andwidth &3s !it width
Latenc" (dela")
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Latenc" (dela")
Tie it takes to send essage fro /oint A to /oint $
Latenc" G 6ro/agation Transit 1ueue
6ro/agation G Distance 3'/eedOfLight
Transit G 'iEe 3 $andwidth
1ueueing not rele&ant for direct links
$andwidth not rele&ant if 'iEe G . !it
'oftware o&erhead can doinate when Distance is sall
#TT4 round8tri/ tie
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Dela" X $andwidth /roduct
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Dela" X $andwidth /roduct
.++s #TT and ?@M!/s $andwidth G @2+ >$ of data
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TC6376 $asics
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'witched networks
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'witched networks
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TC6376 la"ers
6h"sical La"er4 Transitting !its o&er a channel-
Deals with electrical and /rocedural interface to the
transission ediu-
Data Link La"er4 Transfor the raw /h"sical la"er into a Vlink for the
higher la"er- Deals with fraing, error detection, correction and
ulti/le access-
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TC6376 la"ers (contd-)
Network La"er4Addressing and routing of /ackets-
Deals with su!netting, route deterination-
Trans/ort La"er4 end8to8end connection characteristics-
Deals with retransissions, se%uencing and
congestion control-
TC6376 la"ers (contd )
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TC6376 la"ers (contd-)
A//lication La"er4 VVa//lication /rotocols-
Deals with /ro&iding ser&ices to users and a//licationde&elo/ers-
6rotocols are the !uilding !locks of a network
architecture-
Lower la"er ser&ices
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Lower la"er ser&ices
Hnacknowledged connectionless ser&ice
No acknowledgeents, no connection 9rror reco&er" u/ to higher la"ers
For low error8rate links or &oice traffic
Acknowledged connectionless ser&ice Acknowledgeents i/ro&e relia!ilit" For unrelia!le channels- e-g-4 wireless s"stes
Acknowledged connection8oriented ser&ice 9%ui&alent of relia!le !it8strea in8order deli&er"
Connection esta!lishent and release
7nter8router traffic
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T"/ical TC6 !eha&iour
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!
"
#
$
%
%!
%"
% ! & " ' # ( $
Time (round trips)
CongestionW
indowsize
(segments)
Slow start
Congestion
avoidance
Slow start
threshold
T"/ical TC6 !eha&iour
'low start /hase
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'low start /hase
=initialiEe4=Cwnd G .
=for (each AC>)
=Cwnd=until
=loss detection O#
=Cwnd R ssthresh
;ost A
onese)ment
#TT
;ost $
time
twose)ments
*o+rse)ments
Congestion a&oidance /hase
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Congestion a&oidance /hase
3J Cwnd R threshold J3=Hntil (loss detection) B e&er" w AC>s4 Cwnd
=ssthresh G Cwnd3=Cwnd G .=/erfor slow start
1
;ost A ;ost $
time
#TT
*o+rse)ments
*ivese)ments
TC64 Fast retransit and Fast reco&er"
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!
"
#
$
%
Time (round trips)
Windowsize(segments)
advertised window
,*ter *ast recover
TC64 Fast retransit and Fast reco&er"
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*+-.. (WiFi) O&er&iew
Wireless LANs
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Wireless LANs
7nfrared (7rDA) or radio links (Wa&elan) Ad&antages
&er" fle:i!le within the rece/tion area
Ad8hoc networks /ossi!le
(alost) no wiring difficulties
Disad&antages low !andwidth co/ared to wired networks
an" /ro/rietar" solutions
7nfrastructure &3s ad8hoc networks (*+-..)
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Difference !etween wired and wireless
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7f !oth A and C sense the channel to !e idle at the sae
tie, the" send at the sae tie- Collision can !e detected at senderin 9thernet- ;alf8du/le: radios in wireless cannot detect collision at
sender-
, . /
,
.
/
0t1ernet 2,3 4ireless 2,3
Carrier 'ense Multi/le Access (C'MA)
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Carrier 'ense Multi/le Access (C'MA)
Listen !efore "ou s/eak Check whether the ediu is acti&e !efore sending a
/acket (i-e carrier sensing)
7f ediu idle, then transit
7f collision ha//ens, then detect and resol&e
7f ediu is found !us", transission follows4 .8 /ersistent
68 /ersistent
Non8/ersistent
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$inar" 9:/onential $ackoff
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$inar" 9:/onential $ackoff
.-On detecting .stcollision for /acket : station A chooses a nu!er r !etween + and .-
wait for r J slot tie and transit-
'lot tie is taken as J /ro/agation dela"
k- On detecting kthcollision for /acket :
choose r !etween +,.,--,(k.)
When &alue of k !ecoes high (.+), gi&e u/-
#andoiEation increase with larger window, !ut dela"increases-
;idden Terinal 6ro!le
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A and C cannot hear each other-
A sends to $, C cannot recei&e A-
C wants to send to $, C senses a Kfree ediu(C' fails)
Collision occurs at $-
A cannot recei&e the collision (CD fails)-
A is Khidden for C-
., /
Effectofinterferencerange
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Effect of interference range
Transmission #rom 1 2 )i"" #ai"
'olution for ;idden Terinals
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'olution for ;idden Terinals
A first sends a Request-to-Send R!S" to $
On recei&ing #T', $ res/onds #lear-to-Send #!S"
;idden node C o&erhears CT' and kee/s %uiet Transfer duration is included in !oth #T' and CT'
9:/osed node o&erhears a #T'!ut not the CT' Ds transission cannot interfere at $
, . /R56
/56 /56
D,5,
DR56
Co/onents of 7999 *+ ..
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Co/onents of 7999 *+-..architecture
The !asic ser&ice set ($'') is the !asic !uilding!lock of an 7999 *+-.. LAN
The o&als can !e thought of as the co&erage areawithin which e!er stations can directl"
counicate The 7nde/endent $'' (7$'') is the si/lest LAN- 7t
a" consist of as few as two stations
ad-1oc network BSS2BSS1
*+-.. 8 ad8hoc network (DCF)
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( )
Direct counicationwithin a liited range 'tation ('TA)4
terinal with accessechaniss to thewireless ediu
$asic 'er&ice 'et ($'')4grou/ of stations using the
sae radio fre%uenc"
$%&'(( )*+
$''
$%&'(( )*+
$''.
'TA.
'TA?
'TA@
'TA
'TA other stations store ediu reser&ations distri!uted &ia #T' and CT'
t
'7F'
D7F'
data
AC>
defer access
otherstations
recei&er
sender data
D7F'
contention
#T'
CT''7F' '7F'
NA0 (#T')NA0 (CT')
*+-.. 8 6CF 7
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67F'
stationsZNA0
wirelessstations
/oint
coordinator
D.
H.'7F'
NA0
'7F'D
H'7F'
'7F'
'u/erFraet+
ediu !us"
t.
*+-.. 8 6CF 77
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tstationsZNA0
wirelessstations
/ointcoordinator
D for M!/s (Differential 1uadrature 6'>)
/rea!le and header of a frae is alwa"s transitted with . M!/s,rest of transission . or M!/s
chi//ing se%uence4 ., 8., ., ., 8., ., ., ., 8., 8., 8. ($arkercode)
a:- radiated /ower . W (H'A), .++ W (9H), in- .W 7nfrared
*@+8@+ n, diffuse light, t"/- .+ range
carrier detection, energ" detection, s"nchroniEation
'/read8s/ectru counications
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'ource4 7ntersil
D''' $arker Code odulation
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'ource4 7ntersil
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*+-.. 8 MAC la"er
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Traffic ser&ices
As"nchronous Data 'er&ice (andator") DCF Tie8$ounded 'er&ice (o/tional) 8 6CF
Access ethods
DCF C'MA3CA (andator")= collision a&oidance &ia randoiEed !ack8off echanis
= AC> /acket for acknowledgeents (not for !roadcasts)
DCF w3 #T'3CT' (o/tional)
= a&oids hidden3e:/osed terinal /ro!le, /ro&ides
relia!ilit" 6CF (o/tional)
= access /oint /olls terinals according to a list
contention window( d i d ! k ff
*+-.. 8 C'MA3CA
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t
ediu !us"
D7F'D7F'
ne:t frae
(randoiEed !ack8offechanis)
station which has data to send starts sensing the ediu (Carrier'ense !ased on CCA, Clear Channel Assessent)
if the ediu is free for the duration of an 7nter8Frae '/ace(7F'), the station can start sending (7F' de/ends on ser&ice t"/e)
if the ediu is !us", the station has to wait for a free 7F' /lus an
additional rando !ack8off tie (ulti/le of slot8tie) if another station occu/ies the ediu during the !ack8off tie ofthe station, the !ack8off tier sto/s (fairness)
slot tie
direct access ifediu is free D7F'
*+-.. DCF !asic access
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7f ediu is free for D7F' tie, station sends data
recei&ers acknowledge at once (after waiting for '7F') if the /acketwas recei&ed correctl" (C#C) autoatic retransission of data /ackets in case of transission
errors
t
'7F'
D7F'
data
AC>
waiting tie
otherstations
recei&er
senderdata
D7F'
contention
*+-.. #T'3CT'
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7f ediu is free for D7F', station can send #T' with reser&ation/araeter (reser&ation deterines aount of tie the data /acket needs
the ediu) acknowledgeent &ia CT' after '7F' !" recei&er (if read" to recei&e) sender can now send data at once, acknowledgeent &ia AC> other stations store ediu reser&ations distri!uted &ia #T' and CT'
t
'7F'
D7F'
data
AC>
defer access
otherstations
recei&er
sender data
D7F'
contention
#T'
CT''7F' '7F'
NA0 (#T')NA0 (CT')
*+-.. 8 Carrier 'ensing
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In I000 $!;%% carrier sensin is per*ormed
at the air interface (physical carrier sensing), and at the MAC la"er (.irtual carrier sensing)
91sical carrier sensin
detects /resence of other users !" anal"Eing all detected/ackets
Detects acti&it" in the channel &ia relati&e signal strengthfro other sources
Birt+al carrier sensinis done !" sending M6DH durationinforation in the header of #T'3CT' and data fraes
Channel is !us" if eit1erechaniss indicate it to !e
Duration field indicates the aount of tie (in icroseconds)re%uired to co/lete frae transission
'tations in the $'' use the inforation in the duration field toadSust their network allocation &ector (NA0)
*+-.. 8 Collision A&oidance
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7f ediu is not free during D7F' tie--
5o intoCollision A&oidance4Once channel !ecoesidle, wait for D7F' tie /lus a randol" chosen!ackoff tie !efore atte/ting to transit
For DCF the !ackoff is chosen as follows4
When first transitting a /acket, choose a !ackoff inter&al inthe range [+,cw\ cwis contention window, noinall"
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data
wait
$. G @
$ G .@
$. G @
$ G +
data
wait
.% and .! are
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t
!us"
!oe
station.
station
station ., , @-@ or .. M!it3s
short s"nch- 'FD signal ser&ice ;9C /a"load
6LC6 /rea!le
(. M!it3s, D$6'>)
6LC6 header
( M!it3s, D16'>)
@2 .2 * * .2 &aria!le !its
length
.2
2 s , @-@ or .. M!it3s
'hort 6LC6 66DH forat (o/tional)
Channel selection (non8o&erla//ing)9uro/e (9T'7)
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?++
[M;E\
?. ?*
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Hser through/ut (.@++ !"te /ackets)4 @-< (2),.* (?), ? (
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rate ser&ice /a"load
&aria!le !its
2 M!it3s
6LC6 /rea!le signal data
s"!ols. . &aria!le
reser&ed length tail/arit" tail /ad
2.22...? &aria!le
2, , ., .*, ?,
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( )
?* data ? /ilot
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@.@+ [M;E\@.*+ @
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9nhance the current *+-.. MAC to e:/and su//ortfor a//lications with 1ualit" of 'er&ice re%uireents,and in the ca/a!ilities and efficienc" of the /rotocol-
9DCF Contention Window !ased /rioritiEation
= #eal8tie
= $est effort
0irtual collision resol&ed in fa&or of higher /riorit"
Extending DCF: EDCF
EDCF improves upon DCF by
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EDCF improves upon DCF byprioritising trafc
Each trafc class can have adierent contention window
Dierent trafc classes touse dierent interramespaces, called rbitration
!nterrame "pace #!F"$
EDCF contention windowparameters
%o!& #priority$: '()*
F+& wo priority: )-(*.-)
%o!& wo priority:)-(*.-)
ccessto
channe
l
FTP fows + unprioritisedVoIP: larger contentionwindow
Prioritised VoIP calls : smallercontention window
7999 *+-.. 'uar"
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7nfrastructure and ad hoc odes using DCF
Carrier 'ense Multi/le Access $inar" e:/onential !ackoff for collision a&oidance and
congestion control Acknowledgeents for relia!ilit"
6ower sa&e ode for energ" conser&ation Tie8!ound ser&ice using 6CF 'ignaling /ackets for a&oiding 9:/osed3;idden terinal
/ro!les, and for reser&ation
Mediu is reser&ed for the duration of the transission #T'8CT'in DCF
6ollsin 6CF
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Mo!ile 76
Traditional #outing
A routing protocolsets u/ a routing tablein routers
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#outing /rotocol is t"/icall" !ased on Distance80ector orLink8'tate algoriths
#outing and Mo!ilit"
Finding a /ath fro a source to a destination
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Finding a /ath fro a source to a destination
7ssues Fre%uent route changes
= aount of data transferred !etween route changes a"
!e uch saller than traditional networks #oute changes a" !e related to host o&eent
Low !andwidth links
5oal of routing /rotocols decrease routing8related o&erhead find short routes
find Ksta!le routes (des/ite o!ilit")
Mo!ile 76 (#FC
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!ased on 76 address network /refi: deterines the su!net
change of /h"sical su!net i/lies= change of 76 address (confor to new su!net), or
= s/ecial routing ta!le entries to forward /ackets to new su!net
Changing of 76 address DN' u/dates take to long tie
TC6 connections !reak securit" /ro!les
Changing entries in routing ta!les does not scale with the nu!er of o!ile hosts and fre%uent
changes in the location
securit" /ro!les
'olution re%uireents retain sae 76 address, use sae la"er /rotocols
authentication of registration essages,
Mo!ile 764 $asic 7dea
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Ro+ter
%
Ro+ter
&
Ro+ter
!
6 M3
8omeaent
Mo!ile 764 $asic 7dea
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Ro+ter
%
Ro+ter
&
Ro+ter
!
6 M3
8ome aent
7orein aent
move
9ackets are t+nneled
+sin I9 in I9
Mo!ile 764 Terinolog"
Mo!ile Node (MN)
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node that o&es across networks without changing its 76 address
;oe Agent (;A)
host in the hoe network of the MN, t"/icall" a router
registers the location of the MN, tunnels 76 /acketsto the COA
Foreign Agent (FA)
host in the current foreign network of the MN, t"/icall" a router forwards tunneled /ackets to the MN, t"/icall" the default router for
MN
Care8of Address (COA)
address of the current tunnel end8/ointfor the MN (at FA or MN)
actual location of the MN fro an 76 /oint of &iew Corres/ondent Node (CN)
host with which MN is Kcorres/onding (TC6 connection)
Data transfer to the o!ile s"ste
8,
M3!
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7nternet
sender
7,
M3
1ome network
*orein
network
recei&er
%
!
&
.- 'ender sends to the 76 address of MN,
;A interce/ts /acket (/ro:" A#6)- ;A tunnels /acket to COA, here FA,
!" enca/sulation
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7nternet
recei&er
7,
M3
1ome network
*orein
network
sender
%
.- 'ender sends to the 76 address
of the recei&er as usual, FA works as default router
'ource4 'chiller
/3
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Mo!ile 764 Other 7ssues
#e&erse Tunneling
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firewalls /erit onl" Kto/ological correctK addresses a /acket fro the MN enca/sulated !" the FA is now
to/ological correct
O/tiiEations Triangular #outing
= ;A infors sender the current location of MN
Change of FA= new FA infors old FA to a&oid /acket loss, old FA now
forwards reaining /ackets to new FA
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Mesh and Adhoc Networks
Multi8;o/ Wireless
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Ma" need to tra&erse ulti/le links to reach destination
Mo!ilit" causes route changes
Mo!ile Ad ;oc Networks (MAN9T)
;ost o&eent fre%uent
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;ost o&eent fre%uent
To/olog" change fre%uent
No cellular infrastructure- Multi8ho/ wireless links- Data ust !e routed &ia interediate nodes-
B
B
MAC in Ad hoc networks
7999 *+ .. DCF i t l
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7999 *+-.. DCF is ost /o/ular 9as" a&aila!ilit"
*+-.. DCF4 Hses #T'8CT' to a&oid hidden terinal /ro!le
Hses AC> to achie&e relia!ilit"
*+-.. was designed for single8ho/ wireless Does not do well for ulti8ho/ ad hoc scenarios
#educed through/ut 9:/osed terinal /ro!le
9:/osed Terinal 6ro!le
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A starts sending to $-
C senses carrier, finds ediu in use and has towait for A8R$ to end-
D is outside the range of A, therefore waiting is notnecessar"-
A and C are Ke:/osed terinals
, .
/D
Distance8&ector Link8state #outing
$oth assue router knows
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$oth assue router knows
address of each neigh!or cost of reaching each neigh!or
$oth allow a router to deterine glo!al routinginforation !" talking to its neigh!ors
Distance &ector8 router knows cost to each destination
Link state8 router knows entire network to/olog" and
co/utes shortest /ath
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Link 'tate #outing4 9:a/le
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MAN9T #outing 6rotocols
6roacti&e /rotocolsT diti l di t i! t d h t t th t l
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Traditional distri!uted shortest8/ath /rotocols
Maintain routes !etween e&er" host /air at all ties
$ased on /eriodic u/dates ;igh routing o&erhead
9:a/le4 D'D0 (destination se%uenced distance &ector)
#eacti&e /rotocols Deterine route if and when needed
'ource initiates route disco&er"
9:a/le4 D'# (d"naic source routing)
;"!rid /rotocols Ada/ti&e Co!ination of /roacti&e and reacti&e
9:a/le 4 I#6 (Eone routing /rotocol)
D"naic 'ource #outing (D'#)
#oute Disco&er" 6hase4
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"
7nitiated !" source node ' that wants to send /acket todestination node D
#oute #e%uest (##91)floods through the network
9ach node appends own identiierwhen forwarding ##91
#oute #e/l" 6hase4
D on recei&ing the first ##91, sends a #oute #e/l" (##96) ##96 is sent on a route o!tained !" re&ersingthe route
a//ended to recei&ed ##91
##96 includes the routefro ' to D on which ##91 wasrecei&ed !" node D
Data Forwarding 6hase4 ' sends data to D !" source routingthrough interediate nodes
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#oute disco&er" in D'#
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.
,
6 0
7
8
E
D
/
G
I
J
=3ode 8 receives packet RR0@ *rom two nei1
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.
,
6 0
7
8
E
D
/
G
I
J
L
=3ode D does not *orwardRR0@
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.
,
6 0
7
8
E
D
/
G
I
J
L
M
3
2
RR09 607EDN
Represents RR09 control messae
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D'D0
9ach node ad&ertises a onotonicall"
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9ach node ad&ertises a onotonicall"increasing e&en se%uence nu!er for itself
When a node decides that a route is !roken, itincreents the se%uence nu!er of the route
and ad&ertises it with infinite etric Destination ad&ertises new se%uence nu!er
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6rotocol Trade8offs
6roacti&e /rotocols Alwa"s aintain routes
Littl d l f t d t i ti
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Little or no dela" for route deterination
Consue !andwidth to kee/ routes u/8to8date
Maintain routes which a" ne&er !e used
#eacti&e /rotocols Lower o&erhead since routes are deterined on deand
'ignificant dela" in route deterination 9/lo" flooding (glo!al search)
Control traffic a" !e !urst"
Which a//roach achie&es a !etter trade8off de/ends on the traffic ando!ilit" /atterns
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TC6 o&er wireless
7/act of transission errors
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Wireless channel a" ha&e !urst" rando errors
$urst errors a" cause tieout #ando errors a" cause fast retransit
TC6 cannot distinguish !etween /acket lossesdue to congestion and transission errors
Hnnecessaril" reduces congestion window Through/ut suffers
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78TC64 '/lit connection a//roach
6er8TC6 connection state
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/h"sical
link
network
trans/ort
a//lication
/h"sical
link
network
trans/ort
a//lication
/h"sical
link
network
trans/ort
a//licationr:t
6er TC6 connection state
TC6 connection TC6 connection
'noo/ /rotocol
$uffers data /ackets at the !ase station $'
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to allow link la"er retransission When du/acks recei&ed !" $' fro M;
retransit on wireless link, if /acket /resent in !uffer
dro/ du/ack
6re&ents fast retransit at TC6 sender F;
FH MHBS
'noo/ /rotocol
6er TC6 connection state
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F; M;$'wireless
/h"sical
link
networktrans/ort
a//lication
/h"sical
link
networktrans/ort
a//lication
/h"sical
link
networktrans/ort
a//lication
r:t
6er TC68connection state
TC6 connection
7/act of handoffs
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'/lit connection a//roach hard state at !ase station ust !e o&ed to new !ase station
'noo/ /rotocol soft state need not !e o&ed
while the new !ase station !uilds new state, /acket losses a"
not !e reco&ered locall"
Fre%uent handoffs a /ro!le for schees that rel" onsignificant aount of hard3soft state at !ase stations
hard state should not !e lost soft state needs to !e recreated to !enefit /erforance
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M8TC6
When a newack is recei&ed with recei&ers
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ad&ertised window G +, the sender enters/ersist ode
'ender does not send an" data in /ersist ode e:ce/t when /ersist tier goes off
When a /ositi&e window ad&ertiseent isrecei&ed, sender e:its /ersist ode
On e:iting /ersist ode, #TOand cwndaresae as !efore the /ersist ode
TC6 in MAN9T
'e&eral factors affect TC6 /erforance in MAN9T4
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Wireless transission errors a" cause fast retransit, which results in
= retransission of lost /acket
= reduction in congestion window
reducing congestion window in res/onse to errors isunnecessar"
Multi8ho/ routes on shared wireless ediu
Longer connections are at a disad&antage co/ared toshorter connections, !ecause the" ha&e to contend forwireless access at each ho/
#oute failures due to o!ilit"
7/act of Multi8ho/ Wireless 6aths
TC6 through/ut degrades with increase in nu!er of ho/s
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6acket transission can occur on at ost one ho/aong three consecuti&e ho/s 7ncreasing the nu!er of ho/s fro . to , < results in increased
dela", and decreased through/ut
7ncreasing nu!er of ho/s !e"ond < allows siultaneoustransissions on ore than one link, howe&er,degradation continues due to contention !etween TC6Data and Acks tra&eling in o//osite directions
When nu!er of ho/s is large enough (R2), through/utsta!iliEes
mobi"ity ca(ses
7/act of Node Mo!ilit"T> thro(*h!(t de*rades )ith increase in mobi"ity b(t not a")ays
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"in breaa*eres("tin* in ro(te
#ai"(re
T> data and acs
en ro(te discarded
T> sender times o(t-
Starts sendin* !acets a*ain
Ro(te is
re!aired
?o
thro(*h!(t
?o thro(*h!(t
des!ite ro(te re!air
:ar*er ro(te re!air
de"ays are es!ecia""y
harm#("
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WiFi4 Manageent and 'ecurit"
Fi&e ke" areas (FCA6')4 Fault anageent
Network anageent
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Ca/acit" anageent
Accounting(access) anageent
6erforance anageent
'ecurit" anageent
FCA6' at all la"ers of a stack (network,iddleware, a//s)
'ecurit" is the ain area of concern
Wireless Network Manageent
7n addition to the wired network issues,
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,wireless network anageent needs toaddress soe s/ecific issues4
#oaing- 6ersistence of Mo!ile Hnits-
Lack of 'NM6 Agents in Mo!ile Hnits-
Mo!ile Adhoc Networks-
Wireless securit"
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Threats
Disclosure of sensiti&e3confidential data
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Denial of ser&ice (Do') HnauthoriEed access to wireless8ena!led
resources
6otential weakening of e:isting securit"easures on connected wired networks ands"stes
0ulnera!ilities
Wired 9%ui&alent 6ri&ac" (W96) encr"/tionstandard is weak
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#adio signals susce/ti!le to Saing andinterference
6rotocol &ulnera!ilities allow
Network sessions to !e taken o&er !" an intruder
7nSection of in&alid data into network traffic
Network reconnaissance
Default configurations create Ko/en network
9:a/le4 The radio
0ulnera!ilities 8 .
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signal fro awireless network cans/ill o&er fro the!uilding whereaccess /oints arelocated toneigh!oring!uildings, /arkinglots and /u!lic roads-
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0ulnera!ilities 8
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9:a/le4 These/acket traces showhighl" confidentialdata that can !eca/tured fro a
wireless network
Wireless securit" technologies
!!"ications
.ST #or transaction sec(rity
.S@%I% and #or sec(re emai"
.Aava sec(rity sandbo&es
.atabase sec(rity>an (se
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%idd"e)are
ire"ess
:in
.802-11 sec(rity
.:: "in sec(rity
.SS: and T:S
.eb sec(rity +TTS I>S +TT +eaders
.ro&y server sec(rity
T>@I.IS> and )ir"ess ?.%obi"e I
hi*her "eve"services to
com!ensate
#or "o)er "ayers
Tradeo##s in!er#ormance
and sec(rity
'ecurit" and a&aila!ilit" The securit" ' is /ro&ided at the following le&els4
Le&el +4 no securit" s/ecified
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Le&el .4 AuthoriEation and authentication of /rinci/als
Le&el 4 Auditing and encr"/tion (6ri&ac")
Le&el
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Conduct risk assessents to deterine re%uiredle&el of securit"
Liit access to wireless networks through theuse of wireless securit" easures (i-e- *+-..i or
W6A) Maintain logical se/aration !etween wireless
and wired networks 6erfor wireless scans to identif" wireless
networks and a//lications (on a regular !asis) 9nforce wireless network /olicies
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*+-.2 internals
8022 &ogical &in'
7999 *+ fail"
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802!
"edium
#ccess
802!
$h%sical
8021 Bridging
802(
"edium
#ccess
802(
$h%sical
802)
"edium
#ccess
802)
$h%sical
802*
"edium
#ccess
802*
$h%sical
80211
"edium
#ccess
80211
$h%sical
80212
"edium
#ccess
80212
$h%sical
8021*
"edium
#ccess
8021*
$h%sical
+ata&in'
&a%er
$h%sical
&a%er
6ur/ose4
7999 *+-.2
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to ena!le ra/id worldwide de/lo"ent of cost8effecti&e!road!and wireless access /roducts
*+-.24
consists of the $' ($ase 'tation) and ''s('u!scri!er 'tations)
All data traffic goes through the $', and the $' can control theallocation of !andwidth on the radio channel-
*+-.2 is a $andwidth on Deand s"ste-
'tandard s/ecifies4 The air interface, MAC (Mediu Access Control), 6;Y(6h"sical
la"er)
The s/ectru to !e used .+ 8 22 5;E licensed !and
7999 *+-.2
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= Due to the short wa&elength
Line of sight is re%uired
Multi/ath is negligi!le
= Channels @ or * M;E wide are t"/ical= #aw data rates in e:cess of .+ M!/s
8.. 5;E
= 7999 'tandards Association 6roSect 6*+-.2a
= A//ro&ed as an 7999 standard on an , ++ 'rame %> 'rame %> 'rame
% b" b d
' based 802-16 %> rotoco"
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Broadcast hase o)n"in hase%ovab"e bo(ndary
o)n"in
>arrier
C!"in
>arrier C!"in hase Random ccess hase
Broadcast Reserved
%ovab"e bo(ndary
Reserved >ontention
o)n"in
S(b#rame
:/% n/1
C:/% n/1
'rame n/1'rame n
Time re"evance o# +F and %> contro" in#ormation
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C!"in
S(b#rame
Ro(nd tri! de"ay D TE!roc
Band)idth re(est s"ots
Downlink 'cheduling
#adio resources ha&e to !e scheduledaccording to the 1o'(1ualit" of 'er&ice)
t
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/araeters Downlink scheduling4
the flows are si/l" ulti/le:ed
the standard scheduling algoriths can !e used= W##(Weighted #ound #o!in)= 0T(0irtual Tie)= WF1(Weighted Fair 1ueueing)= WFF1(Worst8case Fair weighted Fair 1ueueing)= D##(Deficit #ound #o!in)= DD##(Distri!uted Deficit #ound #o!in)
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0T 0T 4 ais to eulate the TDM(Tie Di&ision Multi/le:ing) s"ste
connection . 4 reser&es @+] of the link !andwidth
connection , < 4 reser&es +] of the link !andwidth
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>onnection 1
vera*e inter/arriva" G 2 (nits
>onnection 1
vera*e inter/arriva" G 2 (nits
>onnection 2
vera*e inter/arriva" G 5 (nits
>onnection 3vera*e inter/arriva" G 5 (nits
'irst/>ome/'irst/Served
service order
irt(a" times
irt(a" >"oc service order
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$andwidth allocation and re%uest echaniss
The ethod !" which the ''('u!scri!er 'tation) canget the !andwidth re%uest essage to the $'($ase
't ti )
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'tation) Hnicast
= When an '' is /olled indi&iduall", no e:/licit essage istransitted to /oll the ''-
= The '' is allocated, in the H68MA6(H/link Ma/), !andwidthsufficient for a !andwidth re%uest-
Multicast
= Certain C7D(Connection 7dentifier) are reser&ed for ulticastgrou/s and for !roadcast essages-
= An '' !elonging to the /olled grou/ a" re%uest !andwidthduring an" re%uest inter&al allocated to that C7D in the H68MA6
$roadcast
$andwidth allocation and re%uest echaniss
H5' 4 The $' /ro&ides fi:ed siEe !andwidth at /eriodic inter&als to H5'-
The '' is /rohi!ited fro sing an contention o//ort nities
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The '' is /rohi!ited fro using an" contention o//ortunities- The $' shall not /ro&ide an" unicast re%uest o//ortunities-
rt6' The $' /ro&ides /eriodic unicast re%uest o//ortunities-
The '' is /rohi!ited fro using an" contention o//ortunities-
nrt6'
The $' /ro&ides tiel" unicast re%uest o//ortunities-
The '' is allowed to use contention re%uest o//ortunities-
$9 The '' is allowed to use contention re%uest o//ortunities-
$andwidth #e%uest85rant 6rotocol
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$'
''.
''
.
-.
-
.- $' allocates !andwidth to ''sfor transitting !andwidthre%uest-
-. ''.transits !andwidthre%uests-
- ''transits !andwidth
re%uests-
?- $' allocates !andwidth to ''sfor transitting data !ased ontheir !andwidth re%uests-
$andwidth is also allocated forre%uesting ore !andwidth-@-. ''.transits data and
!andwidth re%uests-@- ''
transits data and
!andwidth re%uests-
?
@-.
@-
9:a/leTotal H/link $"tes G.++
'' and . $'
Fl H5' t6' t6' $9
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''.Deands4
H5' G +
rt6' G .nrt6' G .@
$9 G
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1o' and 0oice30ideo A//lications
$andwidth and a//lications
%DMA ! 655P#. %DMA !+++
7D57UMT.
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.peed3 kbps
!5%DMA !,655P#.3 %DMA !+++
Transaction Processing
Messaging/Te8t Apps9oice/.M.
Location .er(ices
.till Image Transfers
Internet/9P" Access
Database Access
Document TransferLo& Quality 9ideo
Hig' Quality 9ideo
:,;
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Band&idt'
#e1uirem
ents
Hig'
Lo&
Lo& Hig'Latency .ensiti(ity
Te8te=
mail
7=commerce7#P
9oice
TerminalMode
Internet/intranet
7=mail &it'Attac'ments
.treaming9ideo 9ideo
%onferencing
1ualit" of 'er&ice Network8le&el 1o'
Metrics include a&aila!le !3w, /acket loss rates, etc
9leents of a Network 1o' Architecture
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9leents of a Network 1o' Architecture= 1o' s/ecification (traffic classes)
= #esource anageent and adission control
= 'er&ice &erification and traffic /olicing
= 6acket forwarding echaniss (filters, sha/ers, schedulers)
= 1o' routing A//lication8le&el 1o'
;ow well user e:/ectations are %ualitati&el" satisfied
Clear &oice, Sitter8free &ideo, etc
7/leented at a//lication8le&el4
= end8to8end /rotocols (#T63#TC6)
= a//lication8s/ecific encodings (F9C)
1o' !uilding !locks What kind of /reiu ser&ices
Service/SLA design
;ow uch resources
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;ow uch resources admission control/provisioning
;ow to ensure network utiliEation, load !alancing QoS routing, traffic engineering
;ow to set aside resources in a distri!uted anner signaling, provisioning, policy
;ow to deli&er ser&ices when the traffic actuall" coes in traffic shaping, classification, scheduling
;ow to onitor %ualit", account and /rice these ser&ices network management, accounting, billing, pricing
1o' !ig /icture4 Control3Data /lanes
Control 6lane4 'ignaling Adission Control or
'LA (Contracting) 6ro&isioning3Traffic 9ngineering
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7nternetwork or WANWorkstation
#outer
#outer
#outer
Workstation
Data 6lane4 Traffic conditioning (sha/ing, /olicing, arking etc) at the edge
Traffic Classification Claiing #eser&ed #esources (6er8ho/ $eha&ior8 6;$),
scheduling, !uffer anageent
'er&ices4 1ueuing3'cheduling
>"ass
Traffic
Classes
Traffic
Sources
HHHHHH
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9:tra !its indicate the %ueue (class) for a /acket
;igh __ users get into high /riorit" %ueues, whichare in turn less /o/ulated GR lower dela" and
near8Eero likelihood of /acket dro/
>"ass >
>"ass B
>"ass HHHHHH
HHH
H
1o' and /ricing
1o' 6ricing Multi8class network re%uires differential /ricing
Oth i ll l t ! t i l
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Otherwise all users select !est ser&ice class
'er&ice /ro&iders /ers/ecti&e Low cost (i/leentn, etering, accounting, !illing)
9ncourage efficient resource usage Co/etiti&eness and cost reco&er"
Hsers /ers/ecti&e Fairness and 'ta!ilit"
Trans/arenc" and 6redicta!ilit"
Controlla!ilit"
Multiedia a//lications
Audio
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Audio '/eech (C9L6 t"/e codecs) Music (M6
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%>@%e*aco
T> C
Iv4 Iv6
+-323 S
SI
RTS RS RT>
RT
+-261 %
:3@4 :5
Sonet T% thernet -34
Reservation %eas(rement
net)or9
"in9
!hysica"
!!"icationdaemon
9erne"
'ession 7nitiation 6rotocol ('76)
7n&ite users to sessions
Find the users current location
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Find the user s current location atch with their ca/a!ilities and /references in order
to deli&er in&itation
Modif"3Terinate sessions
'ession Descri/tion 6rotocol ('D6) Hsed to s/ecif" client ca/a!ilities
9:a/le (client can su//ort M6958. &ideo codec,and M6< codecs)
'76 co/onents Hser Agent Client (HAC)
9nd s"stes 'end '76 re%uests
Hser Agent 'er&er (HA')
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Hser Agent 'er&er (HA') Listens for call re%uests
6ro/ts user or e:ecutes /rogra to deterine res/onse
Hser Agent4 HAC /lus HA'
#egistrar #ecei&es registrations regarding current user locations
#edirect 'er&er
#edirects users to tr" other ser&er 6ro:" 'er&er
'76 architecture
6I9 Redirect6
Re+est
Response
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%
!
&
"
'
#
$
?
%
%%
%!
6I9 /lient
6erver
6I9 9roK6I9 9roK
6I9 /lient
(Cser ,ent 6erver)
2ocation 6ervice
%&
%"
p
Media
'76 call flow e:a/le
CSR CSR BR$JF R$JF
I?IT407 th ti t
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407 ro&y (thenticate
>K
I?IT
I?ITI?IT
180 Rin*in*100 Tryin*
100 Tryin*
180 Rin*in*180 Rin*in* 200 $K 200 $K
200 $K
>K>K
>K
B$T+ F RT
BFBF
BF
200 $K 200 $K 200 $K
;-
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6art of larger set of standards (;-
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;-
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5atekee/er4 ost i/ortant co/onent which /ro&ides call control ser&ices
5atewa"4 an o/tional eleent which /ro&ides translation functions
!etween ;-
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Adission control 6erission to co/lete call
Can a//l" !andwidth liits
Method to control LAN traffic
Call signaling3anageent3re/orting3logging
Manageent of 5atewa"
;-
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- 5> resol&es $o! to 76 address through ;-
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#T6 s/ecifies coon a//lication functions
Tailored through odifications and3or additions to theheaders
#T6 consists of a data and a control /art The data /art of #T6 is a thin /rotocol The control /art of #T6 is called #TC6
= %ualit"8of8ser&ice feed!ack fro recei&ers
= snchroniEation su//ort for edia streas
#T6 (contd)
#T6 ser&ices /a"load t"/e identification
se%uence nu!ering tiesta/ing
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se%uence nu!ering, tiesta/ing
deli&er" onitoring, o/tional i:ing3translation-
HD6 for ulti/le:ing and checksu ser&ices #T6 does not /ro&ide
echaniss to ensure %ualit"8of8ser&ice, guaranteedeli&er" or /re&ent out8of8order deli&er" or loss
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Trends
irelessAccess "et&ork
5ate&ay
5ate&ay
Telep'one
"et&ork
%ore "et&ork
Programmable. fts itc'
Programmable.ofts&itc'
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Mobile Access#outer
Mobile Access#outer
IPBase .tations
IPBase .tations
User Profiles ?Aut'entication
-HL#0
)5 AirInterface
>ired Access
*+!,
IP Intranet
IP Intranet
.ofts&itc'.ofts&itc'
Application.er(er
Application.er(er
*+!,
AccessPoint
AccessPoint
AccessPoint
AccessPoint
Internet
O&erla" Networks 8 the glo!al goal
regional
integration of heterogeneous fi:ed ando!ile networks with &ar"ingtransission characteristics
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g
etro/olitan area
ca/us8!ased
in8house
&erticalhando&er
horiEontalhando&er
Future o!ile and wireless networks
7/ro&ed radio technolog" and antennas sart antennas, !ea foring, ulti/le8in/ut ulti/le8out/ut
(M7MO)di i i lti l t i it ! fit f
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= s/ace di&ision ulti/le: to increase ca/acit", !enefit froulti/ath
software defined radios ('D#)
= use of different air interfaces, download new odulation3coding
= re%uires a lot of /rocessing /ower d"naic s/ectru allocation
= s/ectru on deand results in higher o&erall ca/acit"
Core network con&ergence 768!ased, %ualit" of ser&ice, o!ile 76
Ad8hoc technologies s/ontaneous counication, /ower sa&ing, redundanc"
#eferences A-'- Tanen!au- Co/uter Networks- 6earson 9ducation, ++
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",
*+-.. Wireless LAN, 7999 standards, www-ieee-org
0arious #FCs4 #FC ++, @+.,
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Other Tutorials at4 www-it-iit!-ac-in3 sri
Contact Details4
'ridhar 7"er'chool of 7nforation Technolog"
77T $o!a", 6owai, Mu!ai ?++ +2
6hone4 .88@28+@9ail4 sriit-iit!-ac-in
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9:tra 'lides4 A6 'etu/ 'ite 'ur&e"
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