Download What is WIMAX ? - Yola

Sami Alanazi
Net-535 – Fall 2013
Princess Nora University

WiMAX is an IP based, wireless broadband
access technology that provides
performance similar to 802.11/Wi-Fi
networks with the coverage and QOS
(quality of service) of cellular networks.
WiMAX is also an acronym meaning
"Worldwide Interoperability for Microwave
Access (WiMAX).

WiMAX (Worldwide Interoperability for
Microwave Access) is a telecommunications
protocol that provides fixed and mobile
Internet access. The current WiMAX revision
provides up to 40 Mbit/s with the IEEE
802.16m update expected to offer up to 1
Gbit/s fixed speeds.

The name "WiMAX" was created by the
WiMAX Forum, which was formed in June
2001 to promote conformity and
interoperability of the standard. The forum
describes WiMAX as "a standards-based
technology enabling the delivery of last mile
wireless broadband access as an alternative
to cable and DSL".
The key characteristics of the WiMAX system are:

WiMAX is a Time Division Duplex System.

Spectrum requirements are from 10 MHz to 30 MHz
 Frequency band – Licensed: 2.5/2.6 GHz; 3.5 GHz.
 Frequency band – Unlicensed: 5.8 GHz.

Throughput estimates.
 Theoretical: 70 Mbps (for a 20 MHz carrier).

Cell range.
 For 2.5G Hz, 500 m–1.5 km.

The "last mile" or "last kilometer" is the
final leg of delivering connectivity from a
communications provider to a customer.
The phrase is therefore often used by the
telecommunications and cable television
industries. The actual distance of this leg
may be considerably more than a mile,
especially in rural areas.

It is typically seen as an expensive challenge
because "fanning out" wires and cables is a
considerable physical undertaking. Because
the last mile of a network to the user is also
the first mile from the user to the world, the
term "first mile" is sometimes used.

To solve the problem of providing enhanced
services over the last mile, some firms have
been mixing networks for decades. One
example is Fixed Wireless Access, where a
wireless network is used instead of wires to
connect a stationary terminal to the wire-line
network.

WiMAX is a wireless digital communications
system, also known as IEEE 802.16, that is
intended for wireless "metropolitan area
networks". WiMAX can provide broadband
wireless access (BWA) up to 30 miles (50 km) for
fixed stations, and 3 - 10 miles (5 - 15 km) for
mobile stations. In contrast, the WiFi/802.11
wireless local area network standard is limited in
most cases to only 100 - 300 feet (30 - 100m).

Mobile Station : The mobile station as in other
networks connects the user to the base station or the
access network. The major difference with the current
mobiles in the market (e.g. GSM or CDMA) is that this
one needs to be IEEE802.16 compatible. Also, the
mobile must have functionalities such as radio
resource management (e.g. handover, paging, etc.),
mobility management (e.g. location update), power
saving capabilities (there are three power save
classes), AAA (Authentication, Authorization and
Accounting) and Session Management (e.g. triggering
QoS based services).
The access service network connects the mobile subscriber to the IP
backbone using the OFDMA air-interface. It mainly consists of two
parts: base station and ASN Gateway (ASN GW). One ASN may
consist of one or more than one base station and one or more than
one ASN gateway.
 The WiMAX base station works like the GSM base station – with
towers standing high up in the air to broadcast radio signals and can
cover up to 10 km radius. These can reach somewhere around 50 km
or 30 miles but due to certain geographical limitations, they go only
as far as 10 km or 6 miles.
 the ASN Gateway is an interface between the ASN and CSN (e.g.
home agent and AAA server). The ASN gateway is a logical entity
that is responsible for functions such as mobility management, for
example paging, QoS, lawful intercept interface, authenticator, data
flow management, etc.

The Connectivity Service Network performs some key
functions in a WiMAX network. As the name suggests, it
provides connectivity to the external networks such as the
Internet, others. Also it provides policy control for voice,
VPN, etc. services. It is also responsible for IP address
management (DHCP, AAA, etc.) and location, plus
mobility management between the ASNs. The CSN is
responsible for the QoS management as well. The
Connectivity Service Network contains two main
elements:
 Authentication, Authorization and Accounting (AAA) server.
 Home Agent (HA).


There are numerous devices on the market that provide
connectivity to a WiMAX network. These are known as the
"subscriber unit" (SU).
There is an increasing focus on portable units. This includes
handsets (similar to cellular smartphones); PC peripherals
(PC Cards or USB dongles); and embedded devices in
laptops, which are now available for Wi-Fi services.

In addition, there is much emphasis by
operators on consumer electronics devices
such as Gaming consoles, MP3 players and
similar devices. It is notable that WiMAX is
more similar to Wi-Fi than to 3G cellular
technologies.

The WiMAX Forum website provides a list of
certified devices. However, this is not a
complete list of devices available as certified
modules are embedded into laptops, MIDs
(Mobile Internet devices), and other private
labeled devices.

WiMAX gateway devices are available as
both indoor and outdoor versions from
several manufacturers. Many of the WiMAX
gateways that are offered by manufactures
such as Airspan, ZyXEL, Huawei, Motorola,
and Greenpacket are stand-alone self-install
indoor units. Such devices typically sit near
the customer's window with the best WiMAX
signal, and provide:
An integrated Wi-Fi access point to provide
the WiMAX Internet connectivity to multiple
devices throughout the home or business.
 Ethernet ports should you wish to connect
directly to your computer or DVR instead.
 One or two PSTN telephone jacks to connect
your land-line phone and take advantage of
VoIP.



Indoor gateways are convenient, but radio losses mean that
the subscriber may need to be significantly closer to the
WiMAX base station than with professionally-installed
external units.
Outdoor units are roughly the size of a laptop PC, and their
installation is comparable to the installation of a residential
satellite dish. A higher-gain directional outdoor unit will
generally result in greatly increased range and throughput
but with the obvious loss of practical mobility of the unit.

There are a variety of USB dongles on the
market which provide connectivity to a
WiMAX network. Generally these devices are
connected to a notebook or netbook whilst
on the go. Dongles typically have
omnidirectional antennae which are of lowergain compared to other devices, as such
these devices are best used in areas of good
coverage.

HTC announced the first WiMAX enabled
mobile phone, the Max 4G, on Nov 12th
2008.[12] The device was only available to
certain markets in Russia on the Yota
network.

HTC and Sprint Nextel released the second WiMAX enabled
mobile phone, the EVO 4G, March 23, 2010 at the CTIA
conference in Las Vegas. The device, made available on June
4, 2010,[13] is capable of both EV-DO(3G) and WiMAX(4G) as
well as simultaneous data & voice sessions. The device also
has a front-facing camera enabling the use of video
conversations.[14] A number of WiMAX Mobiles are
expected to hit the US market in 2011.

The WiMAX MAC uses a scheduling
algorithm for which the subscriber station
needs to compete only once for initial entry
into the network. After network entry is
allowed, the subscriber station is allocated
an access slot by the base station. The time
slot can enlarge and contract, but remains
assigned to the subscriber station, which
means that other subscribers cannot use it.

In addition to being stable under overload
and over-subscription, the scheduling
algorithm can also be more bandwidth
efficient. The scheduling algorithm also
allows the base station to control Quality of
service (QoS) parameters by balancing the
time-slot assignments among the
application needs of the subscriber station.

As a standard intended to satisfy needs of
next-generation data networks (4G), WiMAX
is distinguished by its dynamic burst
algorithm modulation adaptive to the
physical environment the RF signal travels
through. Modulation is chosen to be more
spectrally efficient (more bits per
OFDM/SOFDMA symbol).

That is, when the bursts have a high signal
strength and a high carrier to noise plus
interference ratio (CINR), they can be more
easily decoded using digital signal processing
(DSP).

In contrast, operating in less favorable
environments for RF communication, the
system automatically steps down to a more
robust mode (burst profile) which means
fewer bits per OFDM/SOFDMA symbol;
with the advantage that power per bit is
higher and therefore simpler accurate
signal processing can be performed.

The more recent Long Term Evolution (LTE)
standard is a similar term describing a
parallel technology to WiMAX that is being
developed by vendors and carriers as a
counterpoint to WiMAX.

Korea launched Wimax at 2nd quarter of 2006
and then launched HSPA one quarter after
launched Wimax. At the end of 2008 there were
8.4 million HSPA subscribers and 350,000
Wimax subscribers in Korea. Almost all of HSPA
subscribers come from 2G and 3G users who
have been tempted to upgrade to new devices
by high subsidies, whereas Wimax subscribers
almost all are newcomers.

Deployment of Wimax is still limited
(spotted), whereas there are well over 100
countries where HSPA networks are
deployed, and even where there is no HSPA
coverage there is backward compatibility
(using HSPA devices) to pre-existing
networks (GSM and WCDMA) with a
roaming infrastructure already in place


As of October 2010, the WiMAX Forum claims
there are over 592 WiMAX (fixed and mobile)
networks deployed in over 148 countries.
Yota is the largest WiMAX network operator
in the world, but has announced that it will
move new network deployments to LTE and,
subsequently, change its existing networks as
well.

High Speed Packet Access (HSPA) is an
amalgamation of two mobile telephony
protocols, High Speed Downlink Packet
Access (HSDPA) and High Speed Uplink
Packet Access (HSUPA), that extends and
improves the performance of existing
WCDMA protocols. A further standard,
Evolved HSPA (also known as HSPA+), was
released late in 2008 with subsequent
adoption worldwide beginning in 2010.

Within the marketplace, WiMAX's main
competition comes from existing, widely
deployed wireless systems such as UMTS,
CDMA2000, existing Wi-Fi and mesh
networking.
Speed vs. Mobility of wireless systems: Wi-Fi, HSPA, UMTS, GSM

In the future, competition will be from the
evolution of the major cellular standards to
so-called 4G, high-bandwidth, low-latency,
all-IP networks with voice services built on
top. The worldwide move to 4G for
GSM/UMTS and AMPS/TIA (including
CDMA2000) is the 3GPP Long Term
Evolution effort.

Cellular technologies for emerging markets :
2G, 3G, and beyond / Ajay R Mishra, 2010