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What is a wireless network₋ Wireless Network vs. a Wired Network₋ The Benefits Wireless Personal Area Network₋ Bluetooth Architecture₋ Bluetooth Application₋ The Bluetooth Protocol Stack₋ The Bluetooth Radio Layer₋ The Bluetooth Base band Layer₋ The Bluetooth L2CAP Layer₋ The Bluetooth Frame Structure Wireless Mobile Network₋ Wireless Application Protocol (WAP) Wireless LANs-WLANs₋ WLAN Topology₋ Physical Layer Technology in WLAN₋ WLAN Protocol (IEEE802.11)

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What is a wireless network, exactly?A wireless local-area network (LAN) uses

radio waves to connect devices such as laptops to the Internet and to your business network and its applications. When you connect a laptop to a WiFi hotspot at a cafe, hotel, airport lounge, or other public place, you're connecting to that business's wireless

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A wired network connects devices to the Internet or other network using cables. The most common wired networks use cables connected to Ethernet ports on the network router on one end and to a computer or other device on the cable's opposite end.

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What Is a Wireless Network? Catching Up with Wired Networks

In the past, some believed wired networks were faster and more secure than wireless networks. But continual enhancements to wireless networking standards and technologies have eroded those speed and security differences.

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Small businesses can experience many benefits from a wireless network, including:

Convenience. Access your network resources from any location within your wireless network's coverage area or from any WiFi hotspot.

Mobility. You're no longer tied to your desk, as you were with a wired connection. You and your employees can go online in conference room meetings, for example.

Productivity. Wireless access to the Internet and to your company's key applications and resources helps your staff get the job done and encourages collaboration تعاون . تشجيع

Easy setup. You don't have to string cables, so installation can be quick and cost-effective.

Expandable. You can easily expand wireless networks with existing equipment, while a wired network might require additional wiring.

Security. Advances in wireless networks provide robust security protections.

Cost. Because wireless networks eliminate or reduce wiring costs, they can cost less to operate than wired networks.

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A Bluetooth WPAN is also called a piconet, and is composed of up to 8 active devices in a master-slave relationship ◦ The first Bluetooth device in the piconet is the master,

and all other devices are slaves that communicate with the master

◦ A piconet typically has a range of 10 meters, although ranges of up to 100 meters can be reached under ideal circumstances

In 1998 – Ericsson, IBM, Toshiba, Nokia and Intel form Bluetooth Special Interest Group (SIG).

Harald Bluetooth – Danish king who lived more than 1000 years ago

Universal short-range wireless capability Uses 2.4-GHz band Available globally for unlicensed users Devices within 10 m can share up to 720 kbps of capacity Supports open-ended list of applications

◦ Data, audio, graphics, video Data rate – 1 Mbps

Data and voice access points◦ Real-time voice and data transmissions

Cable replacement◦ Eliminates need for numerous cable attachments for

connection Ad hoc networking الخاّص الشبكات ربط

◦ Device with Bluetooth radio can establish connection with another when in range

File transferInternet bridgeLAN accessSynchronizationThree-in-one phoneHeadset

Piconet◦ Basic unit of Bluetooth

networking◦ Master and one to seven slave

devices◦ Master determines channel and

phase Scatternet

◦ Device in one piconet may exist as master or slave in another piconet

◦ Allows many devices to share same area

◦ Makes efficient use of bandwidth

Synchronous connection oriented (SCO)◦ Allocates fixed bandwidth between point-to-point

connection of master and slave◦ Master maintains link using reserved slots◦ Master can support three simultaneous links

Asynchronous connectionless (ACL)◦ Point-to-multipoint link between master and all slaves◦ Only single ACL link can exist

The Infrared Data Association (IrDA) defines physical specifications communications protocol standards for the short range exchange of data over infrared light, for uses such as personal area networks (PANs).

IrDA is a very short-range example of free-space optical communication.

IrDA interfaces are used in palmtop computers and mobile phones.

– Require line of sight (LOS) to work (less flexible)– Main advantage: reduced wiring

usually mounted in fixed positions to ensure they will hit their targets

•New version: diffuse infrared, – Operates without a direct LOS by bouncing the infrared signal off

of walls– Only able to operate within a single room and at distances of only

about 50-75 feet

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WPAN (Wireless Personal Area Network)• Is a computer network used for communication amongst

computer devices (including telephones and personal digital assistants) close to one person.

• The reach of a PAN is typically a few meters. • PANs can be used for communication among the personal

devices themselves or for connecting to a higher level network and the Internet.

• A Wireless Personal Area Network (WPAN) can also be made possible with network technologies such as IrDA, Bluetooth .

Infrared Wireless LAN Bluetooth

Also an IEEE standard 802.15

Short Range (at least 10m, up to 70m possible)

Data rates (currently up to 55 Mb/s) Short time to connect (<1s) Peer to peer connectivity Designed to support low power portable

devices Easy to use

Personal home storage Printers & scanners Interactive video gaming Home theater Exchanging information directly between

PDAs Connecting a keyboard or mouse wirelessly

to a desktop computer

Advantages:◦ Dynamic network setup ◦ Usually quick and relatively simple to set up ◦ WPAN enabled devices are usually portable ◦ Needs less technical skills to deploy than LANs or WLANs.

Disadvantages:◦ Typically have a limited range ◦ Currently limited to relatively slow data rates when compared

with WLAN technologies ◦ Compatibility and interoperability issues (WPAN technologies are

not usually compatible with each other. Some WPAN technologies such as Bluetooth are known to have had interoperability issues between devices from different manufacturers.)

◦ As small devices that are often associated with WPANs often have limited potential for adding extra hardware it is sometimes difficult to find suitable upgrade equipment.

◦ Devices with inbuilt WPAN technologies can be considerably more expensive than devices without WPAN technologies.

Peer-to-Peer (Ad Hoc) Topology

◦Can consist of 2 or more PCs with wireless network adapters.◦Sometimes called an Independent(مستقل) BSS (IBSS).◦Limited range.

Consortium◦ Ericsson, Intel, IBM, Nokia, Toshiba - many

members Scenarios

◦ connection of peripheral devices loudspeaker, joystick, headset

◦ support of ad-hoc networking small devices, low-cost

◦ bridging of networks e.g., GSM via mobile phone - Bluetooth – laptop

It does not need any IP infrastructure

Bluetooth wireless technology is a short-range radio technology.

Bluetooth wireless technology makes it possible to transmit signals over short distances between telephones, computers and other devices and thereby simplify communication and synchronization .between devices(تزامن)

The Bluetooth wireless technology comprises hardware, software and interoperability requirements.

Transmits at up to 1 Mbps over a distance of 33 feet and is not impeded by physical barriers

Blue-snarfing, the technique leaves no trace of intrusion, steals (يسرق)the contents of a cellphone's address book , or even gain access to a user's laptop.

"Bluejacking" allows a user to send an anonymous and unauthorized message to another cell user. It has become primarily a means of entertainment for some individuals in crowded places - who'll send anonymous comments like "I like your tie" to people nearby.

Bluetooth was named after the 10th century Danish King Harold Bluetooth, who unified Scandinavia

A standard for Wireless Personal Area Network (WPAN)◦ Provides networking in a very small area

Up to 10 meters (current generation) Up to 100 meters (next generation)

◦ Includes small (1/3 of an inch square) and cheap devices designed to Replace short distance cabling between devices

Keyboards, mouse, handsets, PDAs, etc◦ Provides a basic data rate of 1 Mbps

Can be divided into several voice and data channels

PAN)Personal Area

Network(

LAN)Local Area Network(

WAN)Wide Area Network(

MAN)Metropolitan Area Network(

PAN LAN MAN WAN

Bluetooth

Peer-to-PeerDevice-to-Device

Short

<1 Mbps

802.11a, 11b, 11gHiperLAN2

Enterprise Networks

Medium

2–54 +Mbps

802.11MMDS, LMDS

Fixed, LastMile Access

Medium–Long

22 +Mbps

GSM, GPRS,CDMA, 2.5–3G

PDAs, MobilePhones, Cellular

Access

Long

10–384 Kbps

Standards

Speed

Range

Applications

2.5 GHz Service

LocalLocal WideWideCoverage AreaCoverage Area

SatelliteSatellite

Dat

a R

ates

Dat

a R

ates

9.69.6 KbpsKbps

19.619.6 KbpsKbps

5656 KbpsKbps

11 MbpsMbps

22 MbpsMbps

1010 MbpsMbps

5050 MbpsMbps

Broadband PCS

Spread Spread Spectrum Spectrum Wireless Wireless

LANsLANsInfrared Infrared Wireless Wireless

LANsLANs

Narrow Band Narrow Band Wireless LANsWireless LANs

Circuit and Packet DataCircuit and Packet DataCellular, CDPD, Mobitex, DataTacCellular, CDPD, Mobitex, DataTac

Narrowband PCSNarrowband PCS

802.11 is WiFi

WAP is small handhelds

Every minute counts in a small company and wireless networks are a powerful tool for boosting productivity and encouraging information sharing. With untethered access to documents, emails, applications and other network resources, employees can roam where they need to and have constant access to the tools required to do their jobs.

Here are some of the ways businesses are taking advantage of wireless LANs:

1) Increased mobility and collaboration2) Improved responsiveness3) Better access to information4) Easier network expansion5) Enhanced guest access

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Roam without losing your connection باالتصال تجول Work together more effectively الجماعي العملEmployees who use your wireless LAN can roam

around your office or to different floors without losing their connection. Imagine everyone in a team meeting or in small conferences having access to up-to-the minute communications, and all documents and applications on your network. Similarly, using Voice over Wireless LAN technology, they can have roaming capabilities in their voice communications.

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Connect to the information you need when you need it

Provide better customer serviceCustomers want quick response to queries and

concerns. A wireless network can improve customer service by connecting staff to the information they need. For example, a doctor in a small medical office can access online patient files while moving between exam rooms, or a retail sales person can check on available inventory necessary to write up orders on the showroom floor.

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Connect hard-to-reach areas Improve your processes عمليات تحسينWireless LANs allow a business to bring

network access to areas that would be difficult to connect to a wired network. For example, adding wireless access points to a warehouse can make it easier to check and manage inventory, providing the company with accurate inventory figures in real time.

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Add users quickly Grow your network cost-effectivelyCompanies that need to add employees or

reconfigure offices frequently will immediately benefit from the flexibility wireless LANs provide. Desks can be moved and new employees can be added to the network without the effort and cost required to run cables and wires.

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Give secure network access to customers and business partners

Offer a value-added serviceA wireless network allows your business to

provide secure wireless access to the Internet for guests such as customers or business partners. Retailers, restaurants, hotels and other public-facing businesses can provide this as a unique value-added service.

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Security is vital to wireless networking. Some security methods to consider for your network include:

Data encryption, so only authorized users can access information over your wireless network

User authentication, which identifies computers trying to access the network

Secure access for visitors and guests للضيوف األمن الوصول Control systems, which protect the laptops and other

devices that use the network.

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A cellular network or mobile network is a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver, known as a cell site or base station. In a cellular network, each cell characteristically uses a different set of radio frequencies from all their immediate neighbouring cells to avoid any interference.

When joined together these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones, pagers, etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission.

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Although originally intended for cell phones, with the development of smartphones, cellular telephone networks routinely carry data in addition to telephone conversations:

Global System for Mobile Communications (GSM): The GSM network is divided into three major systems: the switching system, the base station system, and the operation and support system. The cell phone connects to the base system station which then connects to the operation and support station; it then connects to the switching station where the call is transferred to where it needs to go. GSM is the most common standard and is used for a majority of cell phones.

Personal Communications Service (PCS): PCS is a radio band that can be used by mobile phones in North America and South Asia. Sprint happened to be the first service to set up a PCS.

D-AMPS: Digital Advanced Mobile Phone Service, an upgraded version of AMPS, is being phased out due to advancement in technology. The newer GSM networks are replacing the older system.

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A wireless LAN or WLAN is a wireless local area network that uses radio waves as its carrier.

The last link with the users is wireless, to give a network connection to all users in a building or campus.

The backbone network usually uses cables

The wireless LAN connects to a wired LAN

There is a need of an access point that bridges wireless LAN traffic into the wired LAN.

The access point (AP) can also act as a repeater for wireless nodes, effectively doubling the maximum possible distance between nodes.

Complete Wireless Networks The physical size of the network is determined by the maximum reliable propagation range of the radio signals. اّن

االذاعية االشارات بمدى ُمحدَّدُ للشبكةِ الطبيعَي الحجَم Referred to as ad hoc networks Are self-organizing networks without any centralized control مركزية سيطرة أيّ بدون ذاتيةِ تَنظيم شبكاَت Suited for temporary situations such as meetings and conferences. والمؤتمراِت اإلجتماعاِت مثل المؤقتةِ للحاالِت مناسب

They use specialized physical and data link protocols

They integrate into existing networks through access points which provide a bridging function They let you stay connected as you roam from one coverage area to another They have unique security considerations They have specific interoperability requirements They require different hardware They offer performance that differs from wired LANs.

Physical Layer: The wireless NIC takes frames of data from

the link layer, scrambles the data in a predetermined way, then uses the modified data stream to modulate a radio carrier signal.

Data Link Layer: Uses Carriers-Sense-Multiple-Access with

Collision Avoidance (CSMA/CA).

IEEE 802.15

Protocol Architectur

e

802.11a offers speeds with a theoretically maximum rate of 54Mbps in the 5 GHz band

802.11b offers speeds with a theoretically maximum rate of 11Mbps at in the 2.4 GHz spectrum band

802.11g is a new standard for data rates of up to a theoretical maximum of 54 Mbps at 2.4 GHz. 

A family of wireless LAN (WLAN) specifications developed by a working group at the Institute of Electrical and Electronic Engineers (IEEE)

Defines standard for WLANs using the following four technologies◦ Frequency Hopping Spread Spectrum (FHSS)◦ Direct Sequence Spread Spectrum (DSSS)◦ Infrared (IR)◦ Orthogonal Frequency Division Multiplexing (OFDM)

Versions: 802.11a, 802.11b, 802.11g, 802.11e, 802.11f, 802.11i

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