A home wireless network allows multiple digital devices in a home, like computers, laptops, tablets, phones, and printers, to connect and communicate with each other over Wi-Fi. A wireless router broadcasts the Wi-Fi signal, which devices can detect and connect to wirelessly using built-in Wi-Fi adapters or external USB adapters. Common wireless network standards are 802.11b providing speeds up to 11 Mbps and 802.11g providing speeds up to 54 Mbps. The router's firewall, network address translation, and ability to share a single internet connection allow multiple devices on the home network to securely access the internet simultaneously.

1. Wireless Home Networks
A home network or home area network (HAN) is a local area network (LAN)used in residential areas
for communication between digital devices, but it it is used to connect small numbers of digital
devices, computers laptops , tablets, pdas,mobile phones and printers. An important and the most
common function is the sharing of Internet access. If an ISP have only one IP address, a router is
used it has network address translation (NAT), proxy server software and a network firewall, this
allows several computers and other electronic devices to share the IP address.
Network
A network is defined as a system that is used to connect multiple electronic devices together, so
they can exchange the information with each other. Thenetwork are not just established for
offices but is also used for homes because in many homes there is more than one pc.
Any kind of data can be shared on network either files, photos videos or music, and the most
effective use is if u have broadband service at your home then many computers can be connected
to one single connection through wireless network which was not possible earlier or few years back.
http://technet.microsoft.com/en-us/library/cc757419(v=ws.10).aspx
There are two types of network: wired or wireless
Wired Network:
As it is obvious from the name that in wired networks devices are connected with physical wires or
cables on wired network each device should have an Ethernet (RJ-45) port. Each computer then
connects to the router with the help of Ethernet cable or there are few other ways to connect
devices in wired network.
Wireless home network:
Because of this wireless technology the wireless home networks have become friendlierthen
it used to be, it means you no longer have to carry yards of cables from room to room to get
connected.In wireless we just need a wireless router and an adapter that is usually installed on
all modern devices or PCs that you want to connect. Mostly in modern devices the wireless
adapter is built in .
Also wireless networking devices don't need to have ports, but just need antennas, which are
mostly now a days hidden inside the device itself. To have a Wi-Fi connection, an access
point is needed and a Wi-Fi client.
Access Point: In order to broad cast the Wi-Fi signal for Wi-Fi clients an An Access point
(AP) is used . For each wireless network, you need an access point. Although an AP can be
purchased separately, and can be connected to a router or a switch to add Wi-Fi support to a
wired network, but now a days the routers available in shops has a built-in AP. Some routers
even come with more than one access point and are called dual-band AP.
We can think of a Wi –Fi network as a device that has an invisible network port and invisible
cable and the length of this unseen cable is equal to the range of the Wi-Fi.

2. Wi-Fi client:
A Wi-Fi client we means that it includes devices that detects the signal broadcast by an AP,
and they also maintain the connection.A Wi-Fi connection in which AP is used is called the
Infrastructure mode.All laptops, smartphones, and tablets on the market come have built-in
Wi-Fi capability. But if any device doesn’t have its easy to upgrade by using USB or either
by PCIE Wi-Fi adapter.
Difference between Router and Access Point
To connect computer or other devices on to the networkwe need Hub , switches, routers, and
access points, although the all used to connect the different devices to a network but each of
them have different functions.
Routers
Computer communicates using router and the information exchanged between two networks
by using router for eg between home network and the Internet. Routers can be wireless or
wired. For connecting just computers we can use hub and switches but if you want to connect
all your computers to the internet using one modem we need to use router or modem with
built-in router. Routers provide built-in security, it has a a firewall. Routers are more
expensive than hubs and switches.
Access points
Access point is used to provide wireless access to a wired Ethernet network. An access point
is connected into a hub, switch, or router and then sends the wireless signals. This enables
computers and devices to connect to a wired network wirelessly. By using Access points
you can move from one place to another and have wireless access to a network. If you want
to give wirless connection to your computers and you have a router that enables wireless
capability, you don't need an access point. There is no buitin technology in Access points for
sharing Internet connections. To share an Internet connection, you must have an access point
into a router or a modem with a built-in router.
As we know that wireless network offers two modes of configuration Adhoc and infra
structure mode
Ad hoc mode:
In adhoc mode it is not centralizedall computer are connected to each other in peer to peer
connection , Adhoc mode is ok for few devices to connect but for more connections it
becomes complicated and its difficult to manage.
In Adhoc mode the network has no structure and fixed node.No access point is needed in this
mode it is useful for short duration network for small group of people.

3. Infrastructure Mode:
The connections made by infrastructure mode is centralised . For infra structure mode we
need a wireless access point (AP).In order to make the connection to the the WLAN, we
must configure the AP and all wireless clients to use the same SSID. The AP is then
connected to the wired network inorder to establish a wireless clients access. Additional APs
can be added to increase the coverage area and support more clients.The access point has
either one or more antennas that is used to connect u to the wireless nodes.
Frequency bands: These bands are the radio frequencies used by the Wi-Fi standards:
2.4GHz and 5GHz. The 2.4GHz band is currently the most popular, meaning, it's used by
most existing network devices. That plus the fact that home appliances, such as cordless
phones, also use this band, makes its signal quality generally worse than that of the 5GHz
band due to oversaturation and interference.
IEEE 802.11
It is a standard and was found in 1987 to start the standardization of spread spectrum WLAN
that is used in ISM band, and is used for the communication between computers using
WLAN in the 2.4, 3.6, 5 and 60 GHz frequency bands. They are established by the IEEE
LAN/MAN Standards Committee (IEEE 802). Initially it was released in 1997 and had to go
through various changes. It is used by devices To establish wireless networks.

4. IEEE Frequency/Medium Speed Modes Transmission Spread
Standard Range Spectrum
802.11 2.4GHz RF 1 to Ad 20-60 feet DSSS
2Mbps hoc/infrastructure indoors. FSSS
802.11a 5GHz Up to Ad 35 to 115 feet OFDM
54Mbps hoc/infrastructure indoors.
802.11b 2.4GHz Up to Ad 35 to 115 feet DSSS
11Mbps hoc/infrastructure indoors.
802.11g 2.4GHz Up to Ad 38 to 125 feet OFDM,
54Mbps hoc/infrastructure indoors. DSSS
802.11n 2.4GHz/5GHz Up to Ad 70 TO 130 feet OFDM
600Mbps hoc/infrastructure indoors.
FHSS, DSSS, OFDM, and 802.11 Standards
The standard set by the 802.11 had given two standards of spread spectrum DSSS and FSSS,there is
no difference in terms of the speed but only use different technologies.
DSSS
It operates at the radio frequency band of 2.4 GHz and has a data rate of 1 0r 2 Mbps. There is also
an option for fall back which is 1Mbps this is for just in case if the environment is crowded.
FSSS:
The 802.11 standard also used DSSS and had a data rate of 2Mbps this has a fall back i.e 1Mbps for a
crowded environment .
This shows that the data rate is same for both schemes the only difference is in their spread spectrum
technology.
Below all the details are summed up in the following table.
IEEE Standard RF Used Spread Spectrum Data Rate (in Mbps)
802.11 2.4GHz DSSS 1 or 2
802.11 2.4GHz FHSS 1 or 2
802.11a 5GHz OFDM 54
802.11b 2.4GHz DSSS 11
802.11g 2.4Ghz DSSS 54
802.11n 2.4/5GHz OFDM 600 (theoretical)
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5. As seen above that there are different wireless standards set be IEEE 802.11 and it depends
on these standards that how devices communicate inThere are several different wireless
standards that control how devices communicate. The main ones are IEEE 802.11b and IEEE
802.11g – ‘b’ and ‘g’ for short.
The major difference between these two devices is speed.
A wireless ‘b’ device can transfer data at a maximum speed of 11Mbps, while the newer ‘g’
standard can reach speeds of up to 54Mbps.Now adays most common wireless equipment
now available is 802.11g. Although the two standards are compatible with each other,but an
802.11g network may run more slowly if it is connectedto a 802.11b.
Although 802.11 operates at 2.4GHz ISM band no licence is required. and the maximum
data rate is 54 Mbits/s and the net throughput for this is 19 Mbits/s.
Modulation Scheme:
The modulation scheme used in 802.11 is OFDM(Orthogonal Frequency Division
Multiplexing)
Data rate is 54Mbps but it can do automatic rate selection (with fallback to 48, 36, 24, 12, 11,
6, 5.5, 2, 1Mbps).
*They operate in both
point-to-access point (infrastructure mode)
point-to-point (ad hoc mode, peer-to-peer networking).
IEEE 802.11N:
IT is also compatible with IEEE 802.11 b/g
802.11g is the third modulation standard for wLANs. It has a frequency range of about 2.4
GHz band (like 802.11b) but operates at a data rate of 54 Mbit/s, or the net throughput is
about 19 Mbit/s which is similar to 802.11a core, except for some additional legacy overhead
which are there for backward compatibility. The hardware of 802.11g is backwards
compatible with 802.11b hardware. Details of making b and g work well together occupied
much of the lingering technical process. In an 802.11g network, because of the presence of a
legacy 802.11b participant the overall speed of 802.11g network will be reduced.
The modulation scheme used in 802.11g is orthogonal frequency-division multiplexing
(OFDM) copied from 802.11a with data rates of 6, 9, 12, 18, 24, 36, 48, and 54 Mbit/s,
and reverts to CCK (like the 802.11b standard) for 5.5 and 11 Mbit/s and
DBPSK/DQPSK+DSSS for 1 and 2 Mbit/s. Even though 802.11g operates in the same
frequency band as 802.11b, it can achieve higher data rates because of its heritage to
802.11a
Wireless Channels
wireless nodes communicate with each other by using radio frequency signals in the
ISM (Industrial, Scientific, and Medical) band between 2.4 GHz and 2.5 GHz. Each
neighbouring channel is 5MHz from next channel inorder to avoid interference. due to the
spread spectrum effect of the signals, a node
The original 802.11 had two standards DSSS and FSSS, although they both offers the same speed but

6. use different spread spectrum. The first one used used the 2.4GHz radio frequency band and operated at
a 1 or 2Mbps data rate. Since this original standard, wireless implementations have favored DSSS.
The second 802.11 standard used DSSS and had a data rate of 2Mbps peak data rate with an option of
fallbacki.e 1Mbps if the environment is noisy. 802.11, 802.11b, and 802.11g use DSSS. This means that
the underlying modulation scheme is similar between each standard, all DSSS systems to have 2, 11, and
54Mbps 802.11 standards
If we send signals using a particular channel it will utilize frequency spectrum which is12.5
MHz above center channel frequency and 12.5MHZ below the center frequency. If two
different wireless network use neighbouring channel e.g channel 1 and channel 2 it will
cause iinterference with each other. So inorder to avoid interference use two different
channels that has a difference in frequency range for example channel 1 and channel 6 it will
reduce the cross-talk and give better performance.
IEEE 802.11 Protocols and Technologies:
*The IEEE802.11-related protocols and technologies are briefly defined here :
•802.11. The IEEE 802.11 wireless standard had specify the defination of both es the physical
layer and the media access control (MAC) layer.
•Wi-Fi Protected Access (WPA). WPA is an interim standard which was used until the IEEE
802.11i standard was officialy approved. These standards, were used to be a replacement for
the WEP standard, they use various method of data encryption and network authentication.
•Wireless Auto Configuration. The Wireless Auto Configuration feature was introduced in
Windows XP and Windows Server 2003 had an ability to detect the wireless network to
which a connection has to be established, it is based on configured preferences or default
settings.
802.11 Protocol
The IEEE 802 standards committee defines two separate layers, the Logical Link Control
(LLC) and media access control, for the Data-Link layer of the OSI model. The IEEE 802.11
wireless standard defines the specifications for the physical layer and the media access
control (MAC) layer that communicates up to the LLC layer, as shown in the following
figure.
802.11 and OSI Model

7. The components in the 802.11 architecture lie in the MAC sublayer of data-link layer or
the physical layer.
802.11 MAC Frame
802.11 MAC Frame Format
Frame Control Field
The Frame Control field, actually contains the control information which is used to define
the type of 802.11 Mac frame . the number in the following figure represents the no of bits
for each field.
Frame Control Field
Protocol Version
It gives the current version of the 802.11 protocol that is used. When STAs receive this
value they use it to determine if the frame that has been received its version protocol is
supported.
Type
There are three type of frame fields they are control, data, and management.

8. Subtype There are different number of subtype fields for each frame type . Each type
perform certain function and for each type their subtype also perform the specific function.
To DS and From DSIt is only used in data type frames of STAs that belongs to an AP its
function I sthat it indicates whether the frame is going to or leaving from the DS (distributed
system.
More Fragmentsused to give information if more fragments of the frame are still have to
come they can be data or management type..
Retry It basically takes the decision whether data or management frame needs to be
retransmitted or not.
Power ManagementThis indicates the mode of sending STA which could be either in
active mode or power-save mode.
More DataWhen STA is in power save mode it indicates STA the there are more frames to
send by AP. It is also used for APs to show that there are broadcast/multicast frames arestill
there to send.
WEPrepresents if encryption and authentication are used in the frame. for all data frames
and management frames it has to be set.
Ordershow that frames received has to be processed in order.
Duration/ID Field
This is used for control type frames,but should not be used with those who have a subtype of
power save Poll.
Address Fields
There are different address fields depending upon the the frame type, the four address fields
has a combination of the following address types:
BSS Identifier (BSSID). BSSID uniquely identifies each BSS. When the frame is from an STA in
an infrastructure BSS, the BSSID is the MAC address of the AP. When the frame is from a STA
in an IBSS, the BSSID is the randomly generated, locally administered MAC address of the
STA that initiated the IBSS.
Destination Address (DA) It is the MAC address of the destination.
Source Address (SA). It is the MAC address of the original source .
Receiver Address (RA). RA shows the MAC address of the next STA to receive the frame on
the wireless medium.

9. Transmitter Address (TA). The fram transmitted by STA its transmitted address is
represented by TA.
Sequence Control
It is divided into two subfields, the fragment number field and the sequence number field.
Sequence Control Field
Sequence Number shows the sequence number of individual frame.
Fragment Number when each frame of a segmented frame is sent it represent
the sequence number of each frame.
Frame Body
The frame body holds the data or information which is present in either management type or
data type frames.
Frame Check Sequence
On all fields of MAC header and the frame body field the cyclic redundancy
check(CRC) is performed by the transmitting STA to generate the FCS value.
Then this same CRC calculation to determine the values of FCS field to verify if
there is any error occurred in the frame during transmission.
802.11 PHY Sublayer
IEEE 802.11 At the physical (PHY) sublayer, defines a different encoding and transmission
schemes for wireless communications, the most commonly used transmission schemes are
the Frequency Hopping Spread Spectrum (FHSS), Direct Sequence Spread Spectrum (DSSS),
and Orthogonal Frequency Division Multiplexing (OFDM).
Standards for 802.11 at the PHY Layer

10. 802.1X Protocol
The IEEE 802.1X this standard was designed for wired Ethernet networks, it has been
adapted to 802.11 wireless LANs.
Components of 802.1X
{{{{{{{{{{{*Port access entity. A LAN port, also known as port access entity (PAE), is the
logical entity that supports the IEEE 802.1X protocol that is associated with a port. A PAE can
adopt the role of the authenticator, the supplicant, or both.
Authenticator. For wireless connections,for wireless AP’s it acts as the logical LAN port,
through this Authenticator wireless clients in infrastructure mode gain access to other
wireless clients in the network and the wired network.
*Supplicant. For wireless connections, the supplicant is the logical LAN port on a wireless
LAN network adapter that requests access to the other wireless clients and the wired
network by associating with and then authenticating itself to an authenticator.
Whether for wireless connections or wired Ethernet connections, the supplicant and
authenticator are connected by a logical or physical point-to-point LAN segment.
**Authentication server. To verify the credentials of the supplicant, the authenticator uses
an authentication server, which checks the credentials of the supplicant on behalf of the
authenticator and then responds to the authenticator, indicating whether or not the
supplicant is authorized to access the authenticator's services.}}
The following figure shows these components for a wireless LAN network.
Components of IEEE 802.1X Authentication

11. The authentication server can be the following:
A component of the access point. In this case, the AP must be configured with the sets of
user credentials corresponding to the supplicants that will be attempting to connect (it is
typically not implemented for wireless APs).
A separate entity. In this case, the AP forwards the credentials of the connection attempt to
a separate authentication server. Typically, a wireless AP uses the Remote Authentication
Dial-In User Service (RADIUS) protocol to send a connection request message to a RADIUS
server.

12. BLUETOOTH AND PERSONAL AREA NETWORK:
After the boom of Wireless technology for past 2 decades the ,
manufacturers realized that it would be great for consumer to implement
the wireless technology for removing the cumbersome wire that connects
the devices, as consumer find it irritating to move along wire it provide
people mobility within small range these included devices like (wireless
mouse, keyboard, printers, scannners, head phones ) this wireless gives
these devices invisible short distance connection.
Bluetooth is an standard it is used by most of the electronic appliances
manufacturers. In order to communicate devices in Bluetooth it use that
ad-hoc –Mode approach and allow the communication within the range of
10 m.It is designed to have communication over short distance It supports a
large number of channels and power levels.
Bluetooth radio interface basics
The bluetooth operates in the 2.4 GHz ISM band, Bluetooth uses Frequency Hopping Spread
Spectrum (FHSS) techniques with the carrier modulated using Gaussian Frequency Shift
Keying (GFSK).
Since there is interference that has to be avoided by bluetooth the reason for this is the
devices like microwave and corless telephone or baby monitors these are operated on ISM
band . As we discussed above Bluetooth transmission use FHSS so it remains on one
frequency only for a short period of time as the frequency keep on hopping on different
frequency channels , but if incase any error occurs in transmission it has to resend the data
again , and at this time it might be using a difeerent channel which is more likely interference
free. The hopping rate is standardized that is of 1600 hops per second, and the system hops
over all frequencies that are available by using a pre-determined pseudo-random hop
sequence it depends on the Bluetooth address of the master node in the network.
Bluetooth channels and frequencies
The Bluetooth channels are spaced 1 MHz apart, it startsfrom 2 402 MHz to 2 480 MHz.we
can determine this as 2401 + n, where n varies from 1 to 79.
Bluetooth channels is arranged in such a way that Bluetooth channels gives a guard band of
2 MHz at the bottom of the band and 3.5 MHz at the top.

13. Bluetooth pairing
To establish a connectivity between two devices by using a bluetooth a scheme called
bluetooth pairing I sused. Once Bluetooth pairing has established two devices may
communicate with each other.
Bluetooth pairing is simple is done manuallyonce u activate the bluetooth on your device
then bluetooth link can be seen on the phone and other devices within range is also seen and
connect to any device that is known to you that you wanted to connect on.
The Bluetooth pairing process is typically triggered automatically the first time a device
receives a connection request from a device with which it is not yet paired. In order that
Bluetooth pairing may occur, a password has to be exchanged between the two devices. This
password or "Passkey" as it is more correctly termed is a code shared by both Bluetooth
devices. It is used to ensure that both users have agreed to pair with each other.
.