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
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.
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
time, continuous position
location down to a centimeter of resolution results in precision
Requires minimal components resulting in small size
Typical consumption is in microwatts
High Speed WLANs, Mobile Ad
networks, Groundwave Communications, Handheld and Network
home and Intra
office communication. Stealthy
communications provide significant potential for military, law
enforcement, and commercial applications.
Ground penetrating Radar that detects and
identifies targets hidden in foliage, buildings or beneath the
ground. Intrusion Detection Radars, Obstacle Avoidance Radars,
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.
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:
proven OFDM technology: u
sed in IEEE 802.11a and 802.11g
Achieves data rates of
53 to 480 Mbps
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
Work in harmony with IEEE, WiMedia, CEA, 1394
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
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
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).
Fi Alliance (
A global, non
profit industry association of more than 200 member
companies devoted to promoting the growth of wireless Local Area
With the aim of enhancing the user experience for mobile wireless devices,
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
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
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
890 nm and 1550 nm absorption effects are minimal.
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
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.
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.
. 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.