High-speed wireless access

workablejeansMobile - Wireless

Nov 21, 2013 (4 years and 7 months ago)



Recent Developments


Band Radio
Communication (UWB) and

Wireless Fidelity System
(WiFi) and WiMax

Optical Wireless Networks

Advances in 802.11

The Meghadoot Architecture


Band Radio Communication

UWB is a technology developed to transfer large amounts of data
wirelessly over short distances over a very wide spectrum of
frequencies in a short period of time.

The amount of spectrum occupied by a UWB signal, i.e. the bandwidth of
the UWB signal is at least 25% of the center frequency. For example, a
UWB signal centered at 2 GHz would have a minimum bandwidth of 500
MHz and the minimum bandwidth of a UWB signal centered at 4 GHz
would be 1 GHz. The most common technique for generating a UWB signal
is to transmit pulses with durations less than 1 nanosecond.

UWB technology has the capacity to handle the very high bandwidths
required to transport multiple audio and video streams.

UWB will be ideally suited for transmitting data between consumer
electronics (CE), PC peripherals, and mobile devices within short range at
very high speeds while consuming little power.

This technology operates at a level that most systems interpret as noise and,
as a result, does not cause interference to other radios such as cell phones,
cordless phones or broadcast television sets.


Band Radio Communication


UWB Advantages

Extremely Difficult to Intercept

LPI/LPD. Wideband pulsed
radar spreads the signal and allows more users access to a limited
amount of scarce frequency spectrum.

Multipath Immunity

A low path loss and low energy density
minimizes interference to other services. UWB is very tolerant of
interference, enabling operation within buildings, urban areas, and

Precision Network
wide timing

time, continuous position
location down to a centimeter of resolution results in precision
geolocation systems.

Low Cost

Requires minimal components resulting in small size
and weight

Low Power

Typical consumption is in microwatts


UWB Applications



High Speed WLANs, Mobile Ad
Hoc wireless
networks, Groundwave Communications, Handheld and Network
Radios, Intra
home and Intra
office communication. Stealthy
communications provide significant potential for military, law
enforcement, and commercial applications.

Sensor Networks

Ground penetrating Radar that detects and
identifies targets hidden in foliage, buildings or beneath the
ground. Intrusion Detection Radars, Obstacle Avoidance Radars,
and Short
range motion sensing.


Precision Geolocation Systems and high
resolution imaging. Indoor and outdoor tracking down to less than
a centimeter. Good for emergency services, inventory tracking,
and asset safety and security.



WiMedia refers to high data
rate, wireless multimedia networking
applications operating in a wireless personal area network

The WiMedia brand is defined and supported by the WiMedia

The initial WiMedia radio technology will be based on
ultrawideband (UWB) as defined by the MultiBand OFDM
Alliance (MBOA) SIG's PHY and MAC specifications.

The primary goals of the WiMedia Alliance are

to enable coexistence of multi
protocol applications (UWB, 1394 and
TCP/IP among others) and

to enable true multi
vendor interoperability by establishing procedures for
ensuring devices from different manufacturers coexist within the common
UWB radio platform.


UWB Standards

802.15.3a is a group working on UWB standards but could not
decide between the two approaches

multiband OFDM (MOFDM)
from the TI/Intel
led MBOA group, or direct sequence code
division multiple access (DS
CDMA) from Motorola.

Multiband OFDM Alliance SIG (MBOA
SIG) and WiMedia
Alliance have merged to create UWB industry specifications and
certification programs for consumer electronics, mobile and PC

Advantages of the MultiBand OFDM proposal:

based on
proven OFDM technology: u
sed in IEEE 802.11a and 802.11g

Achieves data rates of
53 to 480 Mbps

Support for
4 to 16 simultaneous piconets

Spectrum easily sculpted for
international regulatory domain compliance


for future range/rate improvements

Refer to MBOA at http://www.multibandofdm.org/.


Objectives of MBOA

To develop, publish, and promote the best overall solution for
global UWB standardization

As a formal SIG, publish detailed system specification in May 2004

To support the development of a robust UWB ecosystem

Support industry efforts to develop upper layer protocols and interfaces

Provide a forum for vendors of antennas, RF modules, and test and
measurement equipment

Work in harmony with IEEE, WiMedia, CEA, 1394
TA, Wireless

To ensure the standardization of UWB solutions with the best
coexistence characteristics possible and to continue work with
worldwide regulatory agencies to provide education and seek
specific approval of MBOA
based technology

To enable a single worldwide standard for high bit rate UWB
applications with optimum time
market and maximum benefit
to the broadest number of end consumers


Wireless Fidelity Systems (WiFi)

Wireless Fidelity (WiFi) is the standard for the high
wireless LAN.

A Wi
Fi network can be used to connect computers to each other,
to the Internet, and to wired networks (which use IEEE 802.3 or

Fi networks operate in the unlicensed 2.4 and 5 GHz radio
bands, with an 11/54 Mbps (802.11b/g) or 54 Mbps (802.11a) data
rate Any Wi
Fi product uses the same radio frequency (for
example, 2.4GHz for 802.11b/g, 5GHz for 802.11a).

The Wi
Fi Alliance (

A global, non
profit industry association of more than 200 member
companies devoted to promoting the growth of wireless Local Area
Networks (WLANs).

With the aim of enhancing the user experience for mobile wireless devices,
the Wi
Fi Alliance's testing and certification programs ensure the
interoperability of WLAN products based on the IEEE 802.11 specification.



WiMAX is an acronym that stands for

The WiMAX Forum is an industry
led, non
profit corporation
formed to promote and certify compatibility and interoperability of
broadband wireless products.

The WiMax forum supports the industry
wide acceptance of the
IEEE 802.16 and ETSI HiperMAN wireless MAN standards.


Optical Wireless Networks

Optical wireless communication enables communication using
infrared ray.

Operates outdoor up to 5 Km and indoor a few meters.


Abundance of unregulated bandwidth: 200 THz in the 700

1500 nm range

No multipath fading: Intensity modulation and direct detection

Higher capacity per unit volume

Cost effective at rates near 100 Mbps

Small cell size

At 800

890 nm and 1550 nm absorption effects are minimal.


Multipath dispersion

Limited range

Difficult to operate outdoor

High power requirement

SNR can vary significantly with the distance



Advances in IEEE 802.11

Multimode 802.11 enables dynamically to use 802.11a/b/g.

The 802.11e defined an extension of the 802.11 standard for
quality of service (QoS).

The 802.11f developed specifications for implementing access
points and distribution systems.

The 802.11h developed the MAC layer standard that comply with
European regulations for 5 GHz wireless LAN.

The 802.11i group is working on mechanisms for enhancing
security in the 802.11 standard.

The 802.11j task group is working on mechanisms for enhancing
security in the 802.11 MAC physical layer protocols to
additionally operate in the newly available Japanese 4.9 GHz and
5 GHz bands.

The 802.11n defines standardized modifications to the 802.11
MAC and physical layers to allows at least 100 Mbps.



The meghadoot architecture is a packet
based wireless network
architecture for low
cost rural community networks.

The major goals of the Meghadoot project are

Develop a fully distributed packet
based hybrid wireless network that can
carry voice and data traffic

Provide a low
cost communication system in the rural regions

Provide a low
cost communication network for urban environment

Meghadoot uses a routing protocol called infrastructure
based ad
hoc routing protocol (IBAR).

The end user equipment in Meghadoot is an IEEE 802.11 enabled

Meghadoot is aimed at deploying an 802.11 phone in rural areas,
using Voice over Wireless IP (VoWIP) that promises to free them
from their telephone handsets.

VoWIP is an emerging technology that enables IP voice to be sent
over an 802.11 wireless LAN.


Final Thoughts

Wireless networks are widespread in our daily life.

Fourth generation (4G) WWAN communications systems that are
characterized by high
speed data rates at 20+ Mbps, suitable for
resolution movies and television. It describes two different
but overlapping ideas.

speed wireless access

with a very high data transmission speed, of the
same order of magnitude as a local area network connection (20 Mbps and
up). It can integrate wireless LAN technologies like Wi
Fi, as well as other
potential successors of the current 3G mobile telephone standards.

Pervasive networks
. A user is simultaneously connected to several wireless
access technologies and can seamlessly move between them. These access
technologies can be Wi
Fi, UMTS, EDGE or any other future access
technology. Included in this concept is also smart
radio technology to
efficiently manage spectrum use and transmission power as well as the use
of mesh routing protocols to create a pervasive network .

A cell phone could be an integral part of all wireless standards.