Title: Chaiyut Santananukarn
1-
- Chaiyut Santananukarn
- Assistant Vice President
- chaiyut_at_cattelecom.co.th
2Contents
- Introduction
- What is WiMAX?
- IEEE 802.16 Extensions
- Architecture
- Functionality
- WiMAX Protocol
- Scenario
- Features
- Security Issues
- Benefits
- WiFi vs WiMAX
- WiMAX Applications
- Future of WiMAX
- Conclusion
3Introduction
- Broadband access - ?????????????????????????? DSL
or cable modem ???? At the office
??????????????????????????????????? -
- WiFi access ???????????????? set up WiFi router
?????????????????????????? ???????????????????
restaurants, hotels, coffee shops and libraries.
????????????????? -
- Dial-up access ??????????????????????????
dial-up, ??????????????????? broadband access
??????????????????????????????????????
4 Contd..
- ???????????? broadband access ????????????????????
???????????????????????? - ???????????? WiFi access ????????????????????????
??????? - ??????????????????????????????????????Broadband
??? wireless ????? wired. - WiMAX(Worldwide Interoperability Microwave
Access) provides these features .Its also known
as IEEE 802.16
5What is WiMAX?
- WiMAX (Worldwide Interoperability for microwave
access) - ????????????????????????????????? point-to-multi
point wireless networking - The commercialization of IEEE 802.16 standard
- Solution for Wireless Metropolitan Area Network
(Wireless MAN ) - BWA (Broadband Wireless Access) Solution
- ????????????????????????? (European BWA standard)
- European Telecommunications Standards
Institutes's High-performance radio metropolitan
area network (HiperMAN)
6- WiMAX ?????????????? ???????? IEEE ??????? 802.16
?????????????????????? 3 ?????????? - 802.16 ????????? 1-3 ???? ????????????????????
????????? Line of Sight ??????????????????????????
?????????????? - 802.16a ????????? 3 - 30 ???? ????????? Line of
Sight - 802.16e ????????? 1 - 3 ???? ????????? Line of
Sight ??????????????????????????????? 802.16 ???
802.16a ???????? ?????????????????????????????????
?????????? ???????????????????????
7WiMAX ???????????????
- ???????????????????? IEEE 802.16 ?????
????????????????????? Orthogonal Frequency
Division Multiplexing (OFDM) ?????????????????????
??????????????????????????????? - ??????????????????? OFDM ?????????????????????????
?????????? (sub-carrier) ?????????????????????????
? ?????????????????????????????? (????? kHz)
????????????????????????????????????????????????
8Contd..
- Coverage range up to 50km and speeds up to
70Mbps(shared among users).
9Operation of WiMAX
- WiMAX ?????????? 2 parts
-
- A WiMAX tower, similar in concept to a cell-phone
tower - A single WiMAX tower can provide coverage
to a very large area -- as big as 3,000 square
miles - A WiMAX Receiver The receiver and antenna could
be a small box or PCMCIA card, or they could be
built into a laptop the way WiFi access is today
10Service Types
- Non-Line-Of-Sight
- A Service where a small antenna on your computer
connects to the tower. In this mode, WiMAX uses a
lower frequency range -- 2 GHz to 11 GHz ( ??????
WiFi ) - Line-Of-Sight
- A Service where a fixed dish antenna points
straight at the WiMAX tower from a rooftop or
pole. Line-of-sight transmissions use higher
frequencies, with ranges reaching a possible 66
GHz
11(No Transcript)
12??????? IEEE 802.16 ??????????????????????????????
????? non line-of-sight ?????????????
??????????????????????????????????????????????????
????? line-of-sight
13IEEE 802.16
- IEEE 802.16 was completed on Oct, 2004
- Range - 30-mile (50-km) radius from base station
- Speed - 70 megabits per second
- Line-of-sight not needed between user and base
station - Frequency bands - 2 to 11 GHz and 10 to 66 GHz
(licensed and unlicensed bands) - Defines both the MAC and PHY layers and allows
multiple PHY-layer specifications
14(No Transcript)
15IEEE Extensions
- 802.16a
- use the licensed and license-exempt frequencies
from 2 to 11Ghz - Support Mesh-Network
- 802.16b
- Increase spectrum to 5 and 6GHz
- Provide QoS (for real-time voice and video
service) - 802.16c
- Represents a 10 to 66GHz system profile
- 802.16d
- Improvement and fixes for 802.16a
- 802.16e
- Addresses on Mobile
- Enable high-speed signal handoffs necessary for
communications with users moving at vehicular
speeds
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17Comparison Chart
Technology Standard Usage Throughput Range Frequency
Wi-Fi 802.11a WLAN Upto 54Mbps 300 feet 5Ghz
Wi-Fi 802.11b WLAN Upto11Mbps 300 feet 2.4Ghz
Wi-Fi 802.11g WLAN Upto54Mbps 300 feet 2.4Ghz
WiMAX 802.16d WMAN Upto75Mbps 4-6 Miles 11Ghz
WiMAX 802.16e Mobile WMAN Upto30Mbps 1-3 Miles 2-6Ghz
WCDMA 3G WWAN Upto2Mbps 1-5 Miles 2100Mhz
CDMA 2000 3G WWAN Upto 2.4Mbps 1-5 Miles 2100Mhz
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19Architecture
- P2MP(Point to Multi point)
- Wireless MAN
- BS connected to Public Networks
- BS serves Subscriber Stations(SS)
- Provides SS access to Public Networks
-
- Mesh Architecture
- Optional architecture for WiMAX
20P2MP Architecture
21WiMAX Mesh Architecture
22WiMAX FUNCTIONALITY
23WiMAX Protocol
- Covers MAC layer and PHY layer
- PHY layer
- Transmission Convergence sublayer
- MAC layer
24 WiMAX NETWORK
25Mac and physical layers
26PHY Layer
- In the design of the PHY specification for 1066
GHz, line-of-sight propagation was deemed a
practical necessity. - Because of the point-to-multipoint architecture,
the BS basically transmits a TDM signal, with
individual subscriber stations allocated time
slots serially. - The PHY specification defined for 1066 GHz uses
burst single-carrier modulation with adaptive
burst profiling in which transmission
parameters, including the modulation and coding
schemes, may be adjusted individually to each
subscriber station (SS) on a frame-by-frame
basis. Both TDD and burst FDD variants are
defined. - Channel bandwidths of 20 or 25 MHz (typical U.S.
allocation) or 28 MHz (typical European
allocation) are specified, along with Nyquist
square-root raised-cosine pulse shaping with a
roll off factor of 0.25.
27Contd..
- Adaptive Burst Profiles
- On DL, multiple SS's can associate the same DL
burst - On UL, SS transmits in an given time slot with a
specific burst - Allows use of directional antennas
- Improves range
- Allows use of two different duplexing schemes
- Frequency Division Duplexing (FDD)
- Time Division Duplexing (TDD)
- Support for both full and half duplex stations
28Adaptive PHY
29 FDD (Frequency Division Duplexing)
- In case of FDD both uplink and downlink channels
are on separate frequencies -
- The capability of downlink to be transmitted in
bursts simultaneously supports two different
modulation types - Full Duplex SS's( which can transmit and receive
simultaneously) - Half Duplex SS's( which cannot)
30FDD Frame bursting
31 TDD (Time Division Duplexing)
- In case of TDD both uplink and downlink
transmissions share the same frequency but are
separated on time -
- A TDD frame has a fixed duration and also
consists of one uplink and one downlink frame
- TDD framing is Adaptive
32Time Division Duplexing
33Data Rates
- Data rates determined by exact modulation and
encoding schemes - TDD and FDD supported in 802.16 to accommodate
burst profiling - 802.16a adds OFDM and OFDMA to support NLOS
multipath propagation
34Medium Access Control(MAC)
- WirelessMAN Point-to-Multipoint and optional
mesh topology - Connection-Oriented
- Connection ID(CID),Service Flows(FS)
- MAC layer is further subdivided into three layers
- Convergence sub-layer (CS)
- Common part sub-layer (CPS)
- Privacy sub-layer
35MAC Addressing
- SS has 48-bit 802.3 MAC address
- BS has 48-bit base station ID
- Not a MAC address
-
- Connection ID (CID)
- 16 bit
- Used in MAC PDU
- Connection Oriented Service
36Frame Structure and PDU
- Each MAC packet consists of the three components,
- A MAC header, which contains frame control
information. - A variable length frame body, which contains
information specific to the frame type. - A frame check sequence (FCS), which contains an
IEEE 32-bit cyclic redundancy code (CRC).
37MAC PDU
38 MAC CS Sub Layer
- Interoperability requires convergence sub-layer
to be service specific - Separate CS layers for ATM packet protocols
- CS Layer
- Receives data from higher layers
- Classifies data as ATM cell or packet
- Forwards frames to CPS layer
39Contd..
- Packet Convergence Sub-Layer
- Initial support for Ethernet, VLAN, IPv4, and
IPv6 - Payload header suppression
- Full QoS support
-
- ATM Convergence Sub-Layer
- Support for VP/VC switched connections
- Support for end-to-end signaling of dynamically
created connections - ATM header suppression
- Full QOS support
40MAC CPS Layer
- Performs typical MAC functions such as addressing
- Each SS assigned 48-bit MAC address
- Connection Identifiers used as primary address
after initialization - MAC policy determined by direction of
transmission - Uplink is DAMA-TDM
- Downlink is TDM
-
- Data encapsulated in a common format facilitating
interoperability - Fragment or pack frames as needed
- Changes transparent to receiver
41MAC PDU Types
- Data MAC PDUs
- HT 0
- Payloads are MAC SDUs/segments, i.e., data from
upper layer (CS PDUs) - Transmitted on data connections
-
- Management MAC PDUs
- HT 0
- Payloads are MAC management messages or IP
packets encapsulated in MAC CS PDUs - Transmitted on management connections
- BW Req. MAC PDUs
- HT 1 and no payload, i.e., just a Header
42MAC PDU Transmission
- MAC PDUs are transmitted on PHY bursts
-
- The PHY burst can contain multiple FEC blocks
- Concatenation
- Multiple MAC PDU's can be concatenated into a
single transmission in either uplink or downlink
direction - Fragmentation
- Each MAC SDU can be divided into one or more MAC
PDU's - Packing
- Packs multiple MAC SDU's into a single MAC PDU
43MAC Privacy Sub Layer
- Provides secure communication
- Data encrypted with cipher clock chaining mode of
DES - Prevents theft of service
- SSs authenticated by BS using key management
protocol
44Transmission Convergence Sublayer
- This layer performs the transformation of
variable length MAC protocol data units (PDUs)
into the fixed length FEC blocks (plus possibly a
shortened block at the end) of each burst. - The TC layer has a PDU sized to fit in the FEC
block currently being filled. It starts with a
pointer indicating where the next MAC PDU header
starts within the FEC block. The TC PDU format
allows resynchronization to the next MAC PDU in
the event that the previous FEC block had
irrecoverable errors.
45WiMAX Scenario
- Consider a scenario where a wimax-enabled
computer is 10 miles away from the wimax base
station. - A special encryption code is given to computer to
gain access to base station. - The base station would beam data from the
Internet required for computer (at speeds
potentially higher than today's cable modems) -
-
-
46Contd..
- The user would pay the provider monthly fee for
using the service. The cost for this service
could be much lower than current high-speed
Internet-subscription fees because the provider
never had to run cables. - The WiMAX protocol is designed to accommodate
several different methods of data transmission,
one of which is Voice Over Internet Protocol
(VoIP). - If WiMAX-compatible computers become very
common, the use of VoIP could increase
dramatically. Almost anyone with a laptop could
make VoIP calls.
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48WiMAX Features
- Scalability
- Quality of service
- Range
- Coverage
49Scalability
- The 802.16 standard supports flexible radio
frequency (RF) channel bandwidths. -
The standard supports
hundreds or even thousands of users within one RF
channel. - As the number of subscribers grow the spectrum
can be reallocated with process of sectoring. -
50 Quality Of Service
- Primary purpose of QoS feature is to define
transmission ordering and scheduling on the air
interface. - These features often need to work in conjunction
with mechanisms beyond the air interface in order
to provide end to end QoS or to police the
behaviour or SS. - Standard defines several QoS related concepts.
- - Service flow Qos scheduling.
- - Dynamic service Establishment.
- -Two Phase Activation Model.
51Theory Of Operation
- All protocol mechanisms support Qos for both
uplink and downlink traffic through the SS and
BS. -
- Requirements for QoS
- - A configuration and registration function
to pre configure SS based QoS service flows and
traffic parameters. - - A signalling function for dynamically
establishing Qos enabled service flows and
traffic parameters. - - Utilization of MAC scheduling and QoS
traffic parameters for uplink service flows. - - Utilization of QoS traffic parameters for
downlink service flows.
52 Service flows
- A service flow is a MAC transport service that
provides unidirectional transport of packets
either to uplink packets transmitted by the SS or
to downlink packets transmitted by the
BS. - A service flow is characterized by a set of QoS
parameters such as latency,jitter and throughput
assurances. - In order to standardize operations between SS and
BS these attributes include details of how the SS
requests uplink bandwidth allocations and the
expected behaviour of the BS uplink
scheduler.
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54 Range
- Optimized for up to 50 Km.
- Designed to handle many users spread out over
kilometres. - Designed to tolerate greater multi-path delay
spread (signal reflections) up to 10.0µ seconds.
- PHY and MAC designed with multi-mile range in
mind.
55Coverage
-
- Standard supports mesh network topology.
- Optimized for outdoor NLOS performance.
- Standard supports advanced antenna techniques.
56Security Issues
- Security provides subscribers with privacy across
the fixes broadband wireless network. - Security is implemented by encrypting connections
between SS and BS. - Protection against unauthorized access to the
data transport services is done by enforcing
encryption of the associated service flows
across the network. -
57Security Architecture
- Two component protocols
- - An encapsulation protocol for
encrypting packet data across fixed network.
- - A key management protocol (PKM) providing
the secure distribution of keying data from
BS to SS.
58Packet Data Encryption
- Encryption services are defined as set of
capabilities within the MAC security sub layer.
- MAC Header information specific to encryption is
allocated in the generic MAC header format.
- Encryption is always applied to the MACPDU
payload, generic MAC is no encrypted.
- All MAC management messages shall be sent in
clear to facilitate registration,ranging and
normal operation of the MAC.
59Key Management Protocol
- An SS uses the PKM protocol to obtain
authorization and traffic keying material from
the BS. - PKM protocol is also used for periodic
reauthorization and key refresh.
- PKM uses X.509 certificates and the RSA pubic
-key encryption algorithm to perform key
exchanges between SS and BS.
60Contd..
- PKM protocol adheres to a client/server model.
- SS acts like PKM client and requests for keying
material and BS acts like PKM server and responds
to the requests ensuring that individual SS
clients receive only keying material for which
they are authorized.
- PKM protocol uses MAC management messaging
PKM-RSP messages.
- PKM protocol uses public-key cryptography to
establish a shared secret between the SS and the
BS.
61Security Association
- A security Association is the set of security
information a BS and one or more of its clients
SS s share in order to support secure
communication across the IEEE std 802.16 network. -
- Three types of SA are defined
- Primary SS establishes a primary
security association - during the SS
initialization process. - Static Static SA are provisioned
within the BS. - Dynamic Dynamic SA are established
and eliminated - on fly in response to
the initiation and - termination of
specific service flows. - Static and Dynamic SA can be shared by multiple
SS.
a
62(No Transcript)
63Contd..
- Figure conceptually depicts end-to-end
Authentication, Authorization, and Accounting
(AAA) on 802.16 networks supporting portability
and fully mobile operations. - Encryption (security association) is established
using the PKM-EAP protocol. - Extensible Authentication Protocol (EAP) is
carried over RADIUS or DIAMETER to the
AAA back end. -
64 Contd..
- Intel recommends using an end-to-end tunnelling
protocol such as Protected EAP (PEAP) or
Tunnelled TLS (TTLS) to afford mutual
authentication. - It also recommends 128-bit or better Transport
Layer Security (TLS) encryption to further
enhance end-to-end security (especially in
situations where cryptographically weaker EAP
methods may be deployed).
65Benefits of WiMAX
- Speed
- ???????? broadband service
- Wireless
- ???????????????????????????? lay cables
- ??????????????????????????????
- Broad coverage
- Much wider coverage than WiFi hotspots
66Benefits for Network Service Providers
- Allow service providers to deliver high
throughput broadband based services like VoIP,
high-speed Internet and Video - Facilitate equipment compatibility
- Reduce the capital expenditures required for
network expansion - Provide improved performance and extended range
- Allow service providers to achieve rapid ROI and
maximize revenues (?????? ???????????????) -
67Benefits for consumers
- Range of technology and service level choices
from both fixed and wireless broadband operators
(????????????????) - DSL-like services at DSL prices but with
- portability (?????????? DSL ?????????????????????
?) - Rapidly declining fixed broadband
prices(???????????? ???????????????) - No more DSL installation fees from
- incumbent (????????????????????????????)
68WiFi Vs WiMAX
- Scalability
- Relative Performance
- Quality of Service
- Range
- Coverage
- Security
69Scalability
70Relative Performance
71Quality Of Service (QoS)
72Range
73Coverage
74Security
75Applications
- Fixed last-mile broadband access as a replacement
or substitute for wired DSL, cable, or T1
connections (?????) - Inexpensive backhaul for cell sites and WiFi
hotspots - High speed enterprise connectivity for businesses
- Voice Over Internet Protocol (VOIP)
76(No Transcript)
77Future of WiMAX
- WiMAX will be deployed in three phases
- In the first phase WiMAX technology (based on
IEEE 802.16-2004) provides fixed wireless
connections -
- In the second phase WiMAX will be available as a
cheap and self-installing Subscriber Terminal
(ST), linked to PC and to antenna - The third phase enables portability, thus WiMAX
(based on IEEE 802.16e) will be integrated into
commercial laptops.
78(No Transcript)
79Conclusion
- WiMAX is poised to be the next Big Thing
- WiMAX will connect you to the internet at faster
speeds and from much longer ranges - WiMAX can handle last-mile access in remote areas
(????????????????????) - Mobility can be achieved with design into
computer chips
80Example From Fixed to Mobile Broadband Wireless
81 WiMax Antenna
82