2. What is Wimax
WiMAX is a standards-based technology enabling the
delivery of last mile wireless broadband access as an
alternative to wired broadband like cable and DSL.
WiMAX is a wireless communications standard
designed to provide 30 to 40 megabit-per-second
data rates, providing up to 1 Gbit /s for fixed stations..
Goal: Provide high-speed Internet access to home
and business subscribers, without wires.
3. Wimax Design
WiMAX system components:
1-Tower WiMAX Sender:
Each tower covers an area
of 8000 square kilometers.
2 - Tower WiMAX the Future:
The form is available on the
Antenna type of card or
PCMCIA card.
4. 3-Backhaul:
A WiMAX tower station
can connect directly to the Internet
using a high-bandwidth,
wired connection.
Uses of Wimax
• Connecting Wi-Fi hotspots with other parts of the
Internet.
• Providing a wireless alternative to cable and DSL
for "last mile” broadband access.
• Providing data and telecommunications services.
• Providing a source of Internet connectivity as part of
a business continuity plan.
5. Types of WiMAX
sight:-of-line-Non
Where a mobile Here a small antenna on your computer
connects to the WiMAX tower. In this mode, WiMAX
uses a lower frequency range -- 2 GHz to 11 GHz
(similar to Wi-Fi).
:sight-of-Line
where a fixed dish antenna points straight at the WiMAX
tower from a rooftop or pole. The line-of-sight connection
is stronger and more stable, so it's able to send a lot of
data with fewer errors. Line-of-sight transmissions use
higher frequencies, with ranges reaching a possible 66
GHz..
6. WiMAX ‘s features:
1- The transfer of information at very high speed.
2- Flexible standards and tools operation, where
WiMAX can be working on several types of networks with
different compositions design.
3- Protection and high security where WiMAX support the
following systems:
(AES) Advanced Encryption Standard , as well as
(DES) is Data Encryption Standard. Advantage of these
systems and technology, security and the lack of a high
probability of impenetrable in various stages ( transmitter
.... receiver... the center carrier ).
7. 4- Speed of employment where they can work directly WiMAX
system without the need to download any software or any
supplementary parts of the system and the operator can be used
any package of data packets allowed within the limits of the system
operational.
5- Reduced cost that is, it is relatively cost suitable for various
communication systems where they are making WiMAX systems
according to the measurements of the world in terms of structure
engineering .
6- The broad scope of coverage by using BPSK, QPSK, 16-QAM,
and 64-QAM .
7- The possibility of formation of private networks and efficiently
relatively high and these networks are specific to a particular
institution or organization and the Ministry of the possibility of
making it easier to use a multitude (VoIP) between formations of this
institution
9. WiMAX is a subset of IEEE 802.16
standard
-802.16.1 (10-66 GHz, line-of-sight, up to
134Mbit/s)
802.16.2 (minimizing interference between
coexisting WMANs)
-802.16a (2-11 Ghz, Mesh, non-line-of-sight)
802.16b (5-6 Ghz)-
-802.16c (detailed system profiles)
-P802.16e (Mobile Wireless MAN)
10. Network Model
1-Mobile Stations (MS) used by the end user to
access the network.
A mobile station (MS)[1] [2]comprises all user
equipment and software needed for communication
with a mobile network
The subscriber station (SS) is a fixed wireless node.
2-The access service network (ASN)
An access network is that part of a telecommunications network which
connects subscribers to their immediate service provider.
-Base Station, BS
11. responsible for providing the air interface to the subscriber and
mobile stations
multicast group management
QoS policy enforcement
DHCP (Dynamic Host Control Protocol) proxy
session management
-The ASN-GW may also provide additional functions that
include
intra-ASN location management and paging,
radio resource management and admission control,
caching of subscriber profiles and encryption keys
AAA client functionality
establishment and management of mobility tunnel with base stations
routing to the selected CSN
12. Connectivity service network (CSN
1-Home Agent, HA:
-for the control of the mobility
-The Home Agent serves as an anchor point for subscribers, providing secure
roaming with QOS capabilities
2-Dsn/DHCP
-Translation of domain name into ip address
-Ip address allocation
3-Authentication, Authorisation and Accounting Server, AAA
- As with any communications or wireless system requiring subscription services, an
Authentication, Authorisation and Accounting server is used
4-oss
-customer provisioning
-network monitoring and troubleshooting
5-bss
charging and billing formatting
13. ENHANCEMENTS IN
WIMAXOFDM
Orthogonal Frequency Division Multiplexing, an FDM
Modulation technique for transmitting large amounts of
digital data over a radio wave. OFDM works by splitting
the radio signal into multiple smaller sub-signals that are
then transmitted simultaneously at different frequencies to
the receiver. OFDM reduces the amount of cross talk in
signal transmissions.802.11a WLAN , 802.16 and WiMAX
technologies use OFDM.
Adaptive modulation and coding (AMC):
AMC is an effective mechanism to maximize throughput in
a time-varying channel supports a number of modulation
and forward error correction (FEC) coding schemes and
allows the scheme to be changed on a per user and per
frame basis, based on channel conditions.
14. Link-layer retransmissions:
WiMAX supports automatic retransmission requests (ARQ) at the
link layer for connections that require enhanced reliability. ARQ-
enabled connections require each transmitted packet to be
acknowledged by the receiver; unacknowledged packets are
assumed to be lost and are
retransmitted.
Flexible and dynamic per user resource allocation:
Both uplink and downlink resource allocation are controlled by a
scheduler in the base station. Capacity is shared among multiple
users on a demand basis, using a burst TDM scheme.
Support for TDD and FDD:
IEEE 802.16-2004 and IEEE 802.16e-2005 supports both time
division duplexing and frequency division duplexing, as well as a
half-duplex FDD, which allows for a low-cost system
implementation.
15. Quality-of-service support:
The WiMAX MAC layer has a connection-oriented architecture that is
designed to support a variety of applications, including voice and
multimedia services. WiMAX system offers support for constant bit rate,
variable bit rate, real-time, and non-real-time traffic flows, in addition to
best-effort data traffic. WiMAX MAC is designed to support a large
number of users, with multiple connections per terminal, each with its
own QoS requirement
Robust security:
WiMAX supports strong encryption, using Advanced Encryption
Standard (AES), and has a robust privacy and key-management
protocol. The system also offers a very flexible authentication
architecture based on Extensible Authentication Protocol (EAP),
which allows for a variety of user credentials, including
username/password, digital certificates, and smart cards.
