Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
1
IEEE802.16
IEEE802.16
WiMAX
WiMAX
IEEE802.16
IEEE802.16
•What is W
i-Max?
•How does it differ from W
i-Fi?
•Is the standard finalised?
•What ca
n you do w
ith W
i-Max that you can’t do w
ith other
tech
nologies?
•Is it lik
e 3G?
•Is it availa
ble w
orldwide?
•What are the future challe
nges facing W
i-Max?
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
2
IEEE802.16
IEEE802.16
WiMAX
WiMAX
What is
What is W
iMax
WiM
ax
•Use
s microwaves for the w
ireless transfer of data
•Can be use
d for high-speed, wireless netw
orking at
distance
s of a few kilo
metres
•Wireless (Wi) M
icrowave Access (Ma)
•Use
s OFDM (which allo
ws for Non Line-of-Sight
communications and addresses multipath
issu
es)
•In
cludes TDD and FDD duplexingsu
pport
•Flexible channel size
s (3
.5MHz, 5 M
Hz, 10 M
Hz)
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
3
IEEE802.16
IEEE802.16
WiMAX
WiMAX
How does it differ from
How does it differ from W
iWi --Fi
Fi ??
•Wi-Fich
annels occupy a fixed w
idth of the
spectrum
•WiM
axwill allo
w channel size
s to be decided base
d
on requirements
•WiM
axworks in the license
d spectrum (1
0-66 G
Hz
with some systems operating in bands betw
een 2
GHz and 11 G
Hz). WiFiworks in the unlic
ense
d ISM
band.
•Wi-Fihas a range of about 100m, WiM
axwill
provide services over se
veral km.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
4
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Wi
Wi --Fi
Fivs
vsWiM
ax
WiM
ax
•WiM
AXis designed to provide a higher level of
relia
bility and quality of se
rvice than W
iFi
•WiM
AXis a M
AN protoco
l that will be a w
ireless
alternative to D
SL and T1 level se
rvices for last m
ile
broadband access
•It w
ill act as a back
bone tech
nology for 802.11
hotspots.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
5
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Towerstream
Towerstream, Boston
, Boston
•Towerstream
–Covering greater Boston &
greater
Providence
–12+ Cells in Service
–90%
Coverage
–Over 500 business customers
–5.8 G
Hz
•Multi-tiered Business Services
with SLA’s
–1 M
bps to 8 M
bps
•Courtesy
of ApertoNetw
orks
(2004)
•Coutese
yE. Ja
cobse
n Intel
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
6
IEEE802.16
IEEE802.16
WiMAX
WiMAX
BCL, New Zealand
BCL, New Zealand
•Broadca
st Communications Lim
ited (BCL)
Wholesa
le W
ireless Access N
etw
ork.
•Nationwide deployment from 74 Base
Stations Sites
•Netw
ork designed for 30,000
connections initially
;–
Expansion to 100,000 planned.
•Netw
ork covers around 100,000 sq km
•5.8 G
Hz sp
ectru
m
•Providing H
igh Speed links –longest
distance
of 50 km!
•Data &
Voice
–Each
CPE deliv
ers 2Mbit/s A
symmetric
DSL
–Up to four 64 kbps TDM voice lines
•Courtesy
of Airsp
anNetw
orks, 2004
•Coutese
yE. Ja
cobse
n Intel
Base S
tation
CPE
Range: 50 k
m
Wir
ele
ss D
SL
Covera
ge
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
7
IEEE802.16
IEEE802.16
WiMAX
WiMAX
The Standards
The Standards
See: http://ieee802.org/16/p
ublished.htm
l•
Drafts Under Development
–IE
EE D
raft 802.16f
•Active Standards
–IE
EE D
raft 802.16e
–IE
EE Standard 802.16-2004
–IE
EE Standard 802.16.2-2004
–IE
EE Standard 802.16/C
onform
ance
01-2003
–IE
EE Standard 802.16/C
onform
ance
02-2003
–IE
EE Standard 802.16/C
onform
ance
03-2004
•Obso
lete Standards
–IE
EE Standard 802.16-2001
–IE
EE Standard 802.16a-2003
–IE
EE Standard 802.16c-2002
–IE
EE Standard 802.16.2-2001
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
8
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Standards
Standards
•In
tel are m
ajor developers of WiM
axsilicon and
instrumental in standardising the tech
nology
•DigiW
eband Broadband Ireland have commercial
offerings in Ireland
•Certification –WiM
AXforum
•802.16e offers portable/n
omadic W
iMAX
•Allo
ws for mobility at pedestrian speeds (i.e. you
can w
alk around and m
aintain your co
nnection)
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
9
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Future Standards to be
Future Standards to be
developed
developed
•The first generation of 802.16e w
on’t allo
w fast
hand-off like on a G
SM netw
ork.
•True m
obility (high speed roaming (e.g. on a bus!))
will take some tim
e to develop and standardize and
will appear by the end of 2007 at the earliest.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
10
IEEE802.16
IEEE802.16
WiMAX
WiMAX
What ca
n
What ca
n W
iWi --Max offer?
Max offer?
•Highly practical for use
in developing eco
nomies and rural
areas where the use
of wired broadband is not co
st
effective
•Allo
ws for rapid deployment
•Will spread the benefits of broadband to use
rs m
ore
quickly then possible w
ith a w
ired infrastrucu
tre
•Gives high connection speeds at distance
(cu
rrently you
can get a slow connection over a G
SM netw
ork, or a fast
connection if close
to an 802.11 acc
ess point). W
ill give
Wi-Fisp
eeds se
veral km from a transm
itter
–but max speed only w
hen nearer
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
11
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Benefits
Benefits
•Low installa
tion costs
•Last m
ile access via an external antenna (and
perhaps through a desk
top antenna near a
window).
•Easier to install than W
i-Fi(n
o need for ca
reful
alig
nment of acc
ess points) –goal of easy
self-
instalation
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
12
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Benefits
Benefits
The benefits w
ill beco
me m
ore apparent as the
tech
nology evolves:
•802.16e adds scalability and m
ulti-access
capabilities. (SOFADMA, Sca
lable O
FDM M
ulti-
Access).
•Channel size
s ca
n be varied depending on
requirements.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
13
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Is it lik
e 3G?
Is it lik
e 3G?
•3G sits on a voice netw
ork
•3G has added data capabilities
•WiM
AXis a high speed data service specifica
lly
designed for the purpose
•Cellu
lar netw
orks evolved to m
eet data demands
•Roaming agreements evolved over time
•In
teroperability w
as also build
in over time
•WiM
axaim
s to offer these
from D
ay one
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
14
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Worldwide availa
bility?
Worldwide availa
bility?
•Need agreement on frequencies to use
•Three Frequencies under co
nsideration
•5.8Gz unlicense
d (sa
me as for WiFi). However the
fact that it is unlicense
d lim
its the transm
ission
distance
•2.5GHz and 3.5GHz have been targeted for license
d
use
throughout the w
orld.
•Negotiations are underw
ay at prese
nt.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
15
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Future Challe
nges?
Future Challe
nges?
•Spectrum –
need w
orldwide agreements
•Living up to the H
ype!
•Wi-Fitook over 8 years from standardisation to roll-
out, so industry w
as well prepared
•WiM
axis evolving extremely rapidly.
•May be argued that the excitement needs to be
managed.
•In
tel talks of three-phase
roll-out and
implementation.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
16
IEEE802.16
IEEE802.16
WiMAX
WiMAX
11stst: O
utdoor Subscriber
: O
utdoor Subscriber
Station
Station
Business
Business
Access &
Access &
Backhaul
Backhaul
Hotspot
Hotspot
Backhaul
Backhaul
Wi-Fi
Wi-Fi
802.1
6-2
004
Wi
Wi --FiFi
Premium
Premium
Residential
Residential
Service
Service
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
17
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Wi-Fi
2nd: Add Indoor Subscriber
2nd: Add Indoor Subscriber
Station
Station
Business
Business
Access &
Access &
Backhaul
Backhaul
Consumer
Consumer
Broadband
Broadband
Access
Access
Hotspot
Hotspot
Backhaul
Backhaul
Self Install Indoor
Self Install Indoor
Modem
Modem
Wi
Wi --FiFi
Wi
Wi --FiFi
802.1
6-2
004
Wi
Wi --FiFi
Wi
Wi --FiFi
Wi
Wi --FiFi
Wi
Wi --FiFi
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
18
IEEE802.16
IEEE802.16
WiMAX
WiMAX
3rd: Add Portable Clie
nt
3rd: Add Portable Clie
nt
Business
Business
Access &
Access &
Backhaul
Backhaul
Consumer
Consumer
Broadband
Broadband
Access
Access
Wi-Fi
Hotspot
Hotspot
Backhaul
Backhaul
Wi
Wi --FiFi
802.1
6-2
004
802.1
6e &
Wi
Wi --FiFi
Wi
Wi --FiFi
Wi
Wi --FiFi
Wi
Wi --FiFi
Wi
Wi --FiFi
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
19
IEEE802.16
IEEE802.16
WiMAX
WiMAX
WiM
AX
WiM
AX
Equipment and
Equipment and
Vendors
Vendors
•Base
Station: ~$50K
–CPE: ~$500
–Price
is expected to go down significantly after the interoperability
certification in 2006
•Vendors:
–AirSpanNetw
orks (A
S4030)
–Alvarion(B
reeza
MAX)
–TroposNetw
orks
–ApertoNetw
orks
–NaviniNetw
orks
–Others (Motorola, Nokia, etc.)
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
20
IEEE802.16
IEEE802.16
WiMAX
WiMAX W
hat about the Tech
nical Details?
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
21
IEEE802.16
IEEE802.16
WiMAX
WiMAX
WiM
AX
WiM
AX
•WiM
AX-Worldwide interoperability for Microwave Access
–It is a forum of product certification for interoperability
•Standard: IE
EE 802.16-2004
•Frequency
Spectrum:
–10 -
66 G
Hz (LOS)
–2 –
11 G
Hz (N
LOS) –both license
d and unlicense
d
•Last m
ile tech
nology (MAN/W
AN)
–Support point-to-point co
mmunication
–Support Q
uality of Service (QoS)
•Back
haul tech
nology for wireless LANs (8
02.11)
•Up to 50 km of range w
ith cell radius: 6-10 km
•Shared data rate up to 75 M
bps.
–Support 50 customers w
ith T1-rate w
ireless connections
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
22
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Wireless Frequency
Band
Wireless Frequency
Band
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
23
IEEE802.16
IEEE802.16
WiMAX
WiMAX
WiFi
WiFiand
and W
iMAX
WiM
AX
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
24
IEEE802.16
IEEE802.16
WiMAX
WiMAX
IEEE Standards
IEEE Standards
1. IE
EE 802.16-2001 (10-66GHz)
Air Interface
for Fixed Broadband W
ireless Acc
ess System
2. IE
EE 820.16a-2003 (2-11GHz) –
WiM
AX
3. IEEE 802.16-2004: (1
) + (2)
4. IE
EE 802.16.2 –
Coexistence
5. IE
EE 802.16c –System Profile for 10 -
66GHz
6. IE
EE 802.16e -
mobility
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
25
IEEE802.16
IEEE802.16
WiMAX
WiMAX
802.16 Physica
l Layer
802.16 Physica
l Layer
•Several PHYsare standardized:
–Single-carrier (S
C) for 10-66 G
Hz
–Single-carrier (S
C2) for 2-11 G
Hz
–OFDM for 2-11 G
Hz
–OFDMA for 2-11 G
Hz
•High degree of flexibility for co
st, ca
pability,
services, capacity
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
26
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Physica
l Layer
Physica
l Layer
•PHY is point-to-m
ultipoint and m
esh
topology
•LOS and N
LOS
–Multipath
may be significant (N
LOS)
•Channel BW –
1.5 to 14 M
Hz
•Advance
d power management
•In
terference
mitigation
•Adaptive Antenna System (AAS) and sectored
Antenna
•ARQ on a per-co
nnection basis
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
27
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Point
Point --toto-- M
ultipoint (P
2MP)
Multipoint (P
2MP)
•Wireless M
AN: not a LAN
•Base
Station (BS) co
nnected to public netw
orks
•BS serves Subscriber Stations (S
S)
–BS and SS are stationary
–SS typically
serves a build
ing (business or residence
)
•Provide SS w
ith first-m
ile access to public
netw
orks
•Multiple services, w
ith different QoSpriority,
simultaneously
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
28
IEEE802.16
IEEE802.16
WiMAX
WiMAX
WiM
AX
WiM
AX
Architecture (P2MP)
Architecture (P2MP)
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
29
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Mesh
Architecture (optional)
Mesh
Architecture (optional)
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
30
IEEE802.16
IEEE802.16
WiMAX
WiMAX
LOS
LOS vs
vsNLOS
NLOS
•In
general, >
10 G
Hz is LOS and <
10G can be either
LOS or NLOS
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
31
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Adaptive Antenna System
Adaptive Antenna System
(AAS)
(AAS)
•Optional in 802.16
•Use
multiple antennas to improve the coverage and
the system capacity.
•The spectral efficiency
is increase
d linearly w
ith the
number of antenna elements.
•AAS is able to improve the SNR gain by combining
multiple signals.
•AAS also reduce
s the frequency
interference
betw
een use
rs.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
32
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Power Control
Power Control
•Power co
ntrol is use
d to improve the overall perform
ance
of the
system.
•It is im
plemented by the base station (BS) se
nding power co
ntrol
inform
ation to subscriber stations (S
S) to regulate the transm
itpower
level so
that the level rece
ived at the base
station is at a pre-
determ
ined level.
•The SS transm
its only enough power (as sp
ecified by the BS).
•The power co
ntrol reduce
s the overall power co
nsu
mption of the SS
and the potential interference
with other co
loca
tedbase
stations.
•For LOS the transm
it power of the SS is approxim
ately proportional
to it’s distance
(sq
uare) from the base
station. For NLOS it is heavily
dependant on the interference
.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
33
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Dynamic Frequency
Selection
Dynamic Frequency
Selection
•Optional proce
dure, but required in unlic
ense
d
bands
•DFS consists of
–Requesting and reporting m
easu
rements
–Testing channels for the prese
nce
of primary use
rs
•Detecting primary use
rs
•Ceasing operation on a channel after primary use
rs
have been found
•Selecting and advertising a new channel
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
34
IEEE802.16
IEEE802.16
WiMAX
WiMAX
802.16 R
eference
Model
802.16 R
eference
Model
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
35
IEEE802.16
IEEE802.16
WiMAX
WiMAX
MAC Common Part
MAC Common Part Sublayer
Sublayer
•Supporting m
ultiple acc
ess
•In
the downlin
k, BS does not have to coordinate its
transm
issions, exce
pt for TDD (Tim
e D
ivision D
uplex).
•The uplin
k is sh
ared on a demand basis.
•The m
ultiple-acc
ess proce
dure in the uplin
k is im
plemented
using
–unso
licited bandwidth grants,
–polling, and
–co
ntention proce
dures.
•Vendors can have different im
plementations to optimize
system perform
ance
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
36
IEEE802.16
IEEE802.16
WiMAX
WiMAX
MAC
MAC-- C
PS: Duplex Sch
eme
CPS: Duplex Sch
eme
Support
Support
•On downlin
k, SS is associated w
ith a specific burst.
•On uplin
k, SS is allo
tted a variable length tim
e slot ,
for their transm
issions
•MAC support for duplex sch
emes
•Tim
e-D
ivision D
uplex (TDD)
–Downlin
k &
Uplin
k tim
e share the same R
F channel
–Dynamic asy
mmetry
•Frequency
-Division D
uplex (FDD)
–Downlin
k &
Uplin
k on separate R
F channels
–Static asy
mmetry
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
37
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Frequency
Frequency
-- division duplex
division duplex
(FDD)
(FDD)
•Separated frequency
channel for DL and U
L.
•Unframed FDD for full-duplex SS
•Framed FDD -
downlin
k in bursts
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
38
IEEE802.16
IEEE802.16
WiMAX
WiMAX
TDD Frame
TDD Frame
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
39
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Service Specific Convergence
Service Specific Convergence
Sublayer
Sublayer(S
SCS)
(SSCS)
•Accepting higher-layer data
•Classification (and proce
ssing) of data
•Deliv
ering data to the M
AC layer
•Rece
iving data from the peer entity
•Two convergence
sublayers:
–ATM CS
–Pack
et CS (Ethernet and IP)
•QoS
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
40
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Medium Acc
ess Control (M
AC)
Medium Acc
ess Control (M
AC)
•A M
AC frame consists of header, payload and CRC
•Frames ca
n be conca
tenated, fragmented, or
pack
ed
•One SS m
ay serve m
ultiple tenants
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
41
IEEE802.16
IEEE802.16
WiMAX
WiMAX
MAC Addressing
MAC Addressing
•SS has 48-bit 802.3 M
AC address
•BS has 48-bit base
station ID
–Not a M
AC address
•Connection ID (CID
)
–16 bit
–Use
d in M
AC PDU
–Note that MAC PDU does not have SS M
AC address or
BS ID
•why? co
nnection-oriented service
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
42
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Generic MAC H
eader
Generic MAC H
eader
•Q: Do you see the source and destination M
AC address?
•How does SS and BS acc
ept MAC frames se
nt to them?
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
43
IEEE802.16
IEEE802.16
WiMAX
WiMAX
MAC PDU Transm
ission
MAC PDU Transm
ission
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
44
IEEE802.16
IEEE802.16
WiMAX
WiMAX
SS O
peration
SS O
peration
Netw
ork Entry and Initialisation
Netw
ork Entry and Initialisation
1. Sca
n for downlin
k channel; synch
ronize w
ith BS
2. Obtain uplin
k transm
ission parameters
3. Perform
ranging (acq
uire tim
ing offse
t)
4. Negotiate capabilities
5. Establish connectivity (for upper layer)
6. Establish tim
e of day
7. Transfer operational parameters
8. Set up connections
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
45
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Channel Access and
Channel Access and Q
oS
QoS
•Pack
ets are associated w
ith a service flow
•A service flow has associated Q
oSparameters:
bandwidth, latency
, jitter, and throughput
•Service flows ca
n be static (p
reco
nfigured) or
dynamically
established
•The BS includes authoriza
tion m
odule that approves
or denies every change to the Q
oSparameters
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
46
IEEE802.16
IEEE802.16
WiMAX
WiMAX
QoS
QoSMech
anism
Mech
anism
•Sch
edulin
g services
–Unso
licited grant se
rvice (UGS) –for real-time fixed-size
pack
ets (VOIP,T1/E
1)
–Real-time polling service (rtPS) –for variable-size
pack
ets (MPEG video)
–Non-real-time polling service (nrtPS) –non-real-time
data w
ith variable-sized pack
ets (FTP)
•Best effort service
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
47
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Requests and G
rants
Requests and G
rants
•SSsca
n request bandwidth
•During these
requests, collisions ca
n happen
(CSMA).
•If the request is su
ccessful, the SS w
ill rece
ive a
data grant.
•There are incremental and aggregated requests.
•Requests are per co
nnections, but grants are per
SS only.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
48
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Privacy
Privacy
Sublayer
Sublayer
•Privacy
-encrypting connections SS/B
S•
Encryption has tw
o component protoco
ls–
Enca
psu
lation protoco
l for encrypting pack
et data
–Privacy
key m
anagement (P
KM) protoco
l.
•Protection from theft of se
rvices
Privacy
Key M
anagement (P
KM) Protoco
l:•
Authoriza
tion
•Periodic re-authoriza
tion is required. (w
hy?)
•X.509 digital ce
rtificates.
•Keys and age m
ust be refresh
ed.
•Two sets of keys are alw
ays active.
Meriel Huggard 4ICT9 2004-2005 –delivered by D.Lew
is2007
49
IEEE802.16
IEEE802.16
WiMAX
WiMAX
Current projects within 802.16
Current projects within 802.16
•802.16e –
mobility (approved 7 D
ec 2005)
•802.16f published 1 D
ec 2005
•New project 802.16i opened 7 D
ec 2005
•Physica
l layer below 2 G
Hz
•MAC m
odification to support point-to-point (P
2P)
systems