Unit-6 Bluetooth and WiFi

Que 1. What is Bluetooth? Explain the terms Piconet and Scatternet used in Bluetooth.

Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable unit and maintaining high levels of security.

Bluetooth technology is based on Ad-hoc technology also known as Ad-hoc Pico nets, which is a local area network with a very limited coverage.

PICONET:

1. Bluetooth is a WPAn (Wireless Personal Area Network) open standard that provides an adhoc way of connecting devices in the 10m range.
2. It is a short range, low cost and power efficient radio technology that supports point-topoint andpoint-to-multipoint connections.
3. It connects handheld devices like printers, laptops, mobile phones and other accessories in the 10m radius. It operates in the ISM band. Bluetooth operates in the 2.4GHz band and uses a frequency hopping TDD method for each radio channel
4. The Bluetooth enabled devices can locate each other, but user action is essential in order to make connections with other devices and from networks.
5. Upto eight devices can be connected in a Bluetooth network called, PICONET.
6. One of them acts as a master and remaining act as slaves. Hence, a maximum of 7 slaves can be supported inside a piconet.
7. Whenever two or more devices detect each other and communicate through Bluetooth, a PICONET is formed.

SCATTERNET:

1. Eight devices can be considered in a Bluetooth network called Piconet. One of them acts as a master and other act a slave.
2. A scatter-net is formed when two or more piconets connect through a bridge node.
3. In addition to seven active slaves, there can be up to 255 parked nodes in the net that can only respond to a beacon signal from the master.
4. The slaves are dumb devices that do the task that the master tells them to do.
5. All the communication is between the master and slave and not between the slaves.

Que 2. Draw and explain in detail Bluetooth protocol architecture.

The protocol architecture of the Bluetooth consists of following in a Bluetooth protocol stack:

1. Radio (RF) layer: It specifies the details of the air interface, including frequency, the use of frequency hopping and transmit power. It performs modulation/demodulation of the data into RF signals. It defines the physical characteristics of Bluetooth transceivers. It defines two types of physical links: connection-less and connection oriented.
2. Baseband Link layer: The baseband is the digital engine of a Bluetooth system and is equivalent to the MAC sublayer in LANs. It performs the connection establishment within a piconet, addressing, packet format, timing and power control.
3. Link Manager protocol layer: It performs the management of the already established links which includes authentication and encryption processes. It is responsible for creating the links, monitoring their health, and terminating them gracefully upon command or failure.
4. Logical Link Control and Adaption (L2CAP) Protocol layer: It is also known as the heart of the Bluetooth protocol stack. It allows the communication between upper and lower layers of the Bluetooth protocol stack. It packages the data packets received from upper layers into the form expected by lower layers. It also performs segmentation and multiplexing.
5. Service Discovery Protocol (SDP) layer: It is short for Service Discovery Protocol. It allows discovering the services available on another Bluetooth-enabled device.
6. RF comm layer: It is a cabal replacement protocol. It is short for Radio Frontend Component. It provides a serial interface with WAP and OBEX. It also provides emulation of serial ports over the logical link control and adaption protocol(L2CAP). The protocol is based on the ETSI standard TS 07.10.
7. OBEX: It is short for Object Exchange. It is a communication protocol to exchange objects between 2 devices.
8. WAP: It is short for Wireless Access Protocol. It is used for internet access.
9. TCS: It is short for Telephony Control Protocol. It provides telephony service. The basic function of this layer is calling control (setup & release) and group management for the gateway serving multiple devices.
10. Application layer: It enables the user to interact with the application.

Que 3. Draw and explain the Bluetooth frame structure and Network connection.

Bluetooth packet can be of 1-slot (625 us) or 3-slot (1875 us) or 5-slot (3125 us).

• Each packet consists of a 72-bit access code.
• The access code is used for packet identification.
• Every packet exchanged on the channel is preceded by its access code.
• Recipients on the piconet compare incoming signals with access code. If the two do not match, the received packet is not considered valid and rest of its contents are ignored.
• The 72-bit access code is derived from master identity.
• Thus, access code is also used for synchronization and compensating for offset.

• Header part of the packet is used by the Link Control (LC) logical channel. It has the following format:

• AM_ADDR: temporary address assigned to active members of the piconet, used on all packets in both directions sent between the master and the addressed slave
• TYPE: type of packet. There are 12 types of packets for each SCO and ACL physical links, and four types of common control packets for both
• FLOW: It is used for flow control. It is asserted by slave when its buffer is full and cannot receive any more data.
• ARQN: It is used to piggy back an acknowledgement onto a frame.
• SEQN: It contains sequence number for packet ordering.
• HEC: header error check for header integrity.
• There can be two types of payloads: voice and data. Synchronous connection oriented (SCO) packets only have voice field, while Asynchronous connection less (ACL) packets only have data field.

Que 4. Enlist the advantages, disadvantages and applications of Bluetooth.

Advantages of Bluetooth: there are many benefits and advantages to using wireless devices.

1. Bluetooth is actually inexpensive: The technology of Bluetooth is cheap for companies to implement, which results in lower costs for the company.
2. Bluetooth is automatic: Bluetooth doesn’t have you set up a connection or push any buttons.
3. Standardized protocol: Bluetooth is standardized wireless, meaning that a high level of compatibility among devices is guaranteed.
4. Low interference: Bluetooth devices almost always avoid interference from other wireless devices.
5. Low energy consumption: As a result of Bluetooth using low power signals, the technology requires very little energy and will use less battery or electrical power as a result.
6. Sharing voice and data: The standard for Bluetooth will allow compatible devices to share data and voice communications. This is great for mobile phones and headsets, as Bluetooth simplifies driving and talking on your cell phone.
7. Instant PAN (Personal Area Network): You can connect up to seven Bluetooth devices to each other within a range of up to 30 feet, forming a piconet or PAN. For a single room, you can also set up multiple piconets.
8. Upgradeable: Upgradeable is the standard for Bluetooth. There are newer versions of Bluetooth in the works, which offer many new advantages and backward compatible with older versions.
9. The technology stays: Bluetooth technology is a worldwide, universal wireless standard. With it being as popular as it is, you can count on it being around for years to come.

Disadvantages:

The only real downsides are the data rate and security. Infrared can have data rates of up to 4 MBps, which provides very fast rates for data transfer, while Bluetooth only offers 1 MBps.

Although there are very few disadvantages, Bluetooth still remains the best for short range wireless technology.

1. Bluetooth Security Issues: There are a number of ways in which Bluetooth security can be penetrated, often because there is little security in place. The major forms of Bluetooth
   security problems fall into the following categories:
   a. Bluejacking: Bluejacking is often not a major malicious security problem, although there can be issues with it, especially as it enables someone to get their data onto another person’s phone, etc.
   b. Bluebugging: This more of an issue. This form of Bluetooth security issue allows hackers to remotely access a phone and use its features.
   c. Car Whispering: This involvesthe use ofsoftware that allows hackersto send and receive audio to and from a Bluetooth enabled car stereo system.

Applications of Bluetooth: –

Following are some of the capabilities that Bluetooth can provide consumers: –

1. Make calls from a wireless headset connected remotely to a cell phone.
2. Eliminate cables linking computers to printers, keyboards, and the mouse.
3. Hook up MP3 players wirelessly to other machines to download music.

Que 5. Write a short note on “Wi-Fi Technology”.

1. Wi-Fi is a technology that uses radio waves to provide network connectivity. It stands for wireless frequency. Wi-Fi uses radio waves to transmit information between your device and a router via frequencies.
2. Wi-Fi is a blanket term for multiple technologies that use the IEEE 802.11 communications standards to create local area networks or LANs. Wi-Fi-enabled products use radio waves to transmit data and communicate with one another. Initially the technology used the GHz frequency, but it has since expanded to 5 GHz, 60 GHz, and 6
   GHz frequency bands.
3. Wi-Fi, at a basic level, works on the same principles that make your radio or over-the-air TV possible. Wi-Fi devices send radio waves to one another—but instead of broadcasting analog audio or video, these waves digitally encode network packets that comply with the Internet Protocol, just like the ones sent over wired Ethernet connections.

The basic components of a Wi-Fi network include:

• A router, which does the traffic among the devices on the network. The router serves the key role in mediating between all the devices on your local network and internet.
• A wireless access point that provides the radio connection between the router and the local wireless devices.
• A modem that connects the local network to the wider internet. While not strictly necessary for making the Wi-Fi network work, without it the devices on the network can only talk to each other and not the wider world.

802.11 Standard

• Wi-Fi is a technology for wireless local area networking with devices based on the IEEE 802.11 standards.
• Wi-Fi is a trademark of the Wi-Fi Alliance, which restricts the use of the term Wi-Fi Certified to products that successfully complete interoperability certification testing.
• Devices that can use Wi-Fi technology include personal computers, video-game consoles, phones and tablets, digital cameras, smart TVs, digital audio players and modern printers.
• Wi-Fi compatible devices can connect to the Internet via a WLAN and a wireless access point. Such an access point (or hotspot) has a range of about 20 meters (66 feet) indoors and a greater range outdoors.
• Hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points. Wi-Fi most commonly uses the 2.4 gigahertz (12 cm) UHF and 5.8 gigahertz (5 cm) SHF ISM radio bands.
• Anyone within range with a wireless modem can attempt to access the network; because of this, Wi-Fi is more vulnerable to attack (called eavesdropping) than wired networks.

Wi-Fi Security

• Initially, most Wi-Fi networks were open, with data traveling over the air unsecured. This posed a problem for companies concerned that an employee connecting from a public coffee shop could be leaking data to anyone else in the room who had a Wi-Fi receiver.
• The Wi-Fi Alliance addressed by adding different security protocols to the standard under the Wi- Fi Protected Access banner, including the latest, WPA3. Users connecting to secured access points through properly configured WPA and a VPN connection are now generally secure from some of the technology’s earlier open-network issues.

Que 6. Explain the advantages and disadvantages of Wi-Fi Technology.

Advantages of Wi-Fi/wireless networking :

1. Increased efficiency

Improved data communications lead to faster transfer of information within businesses and between partners and customers. For example, salespeople can remotely check stock levels and prices while on sales calls.

2. Access and availability

Because wireless technology allows the user to communicate while on the move, you are rarely out of touch – you don’t need extra cables or adaptors to access office networks.

3. Flexibility

Office-based wireless workers can network without sitting at dedicated computers and can continue to do productive work while away from the office. This can lead to new styles of working, such as home working or direct access to corporate data while on customer sites. See more on employees working from home.

4. Cost savings

Wireless networks can be easier and cheaper to install, especially in listed buildings or where the landlord will not permit the installation of cables.

5. New opportunities

Wireless networking could allow you to offer new products or services. For example, many airport departure lounges, train stations, hotels, cafes and restaurants have installed ‘hot spot’ WiFi services to allow mobile users to connect their equipment to their ‘home’ offices while travelling.

Disadvantages of Wi-Fi/wireless networking

Despite the many benefits that wireless can claim over wired networks, there are also potential Wi-Fi disadvantages also.

1. Security

Wireless transmission is more exposed to attacks by unauthorised users, so you must pay particular attention to securing your wireless systems.

2. Installation problems

You may experience interference if others in the same building also use wireless technology, or where other sources of electromagnetic (radio) interference exist. This could lead to poor communication or, in extreme cases, complete loss of wireless communication.

3. Coverage

In some buildings, getting consistent coverage can be difficult, leading to ‘black spots’ where the signal isn’t available.

4. Transmission speeds

Wireless transmission can be slower and less efficient than ‘wired’ networks. In larger wireless networks, the ‘backbone’ network is usually wired or fibre rather than wireless.

Que 7. Differentiate between Wi-Fi and Bluetooth technology.

Sr. No.	Parameter	Wi-Fi	Bluetooth
1	Full Form	Full-form of Wi-Fi is Wireless Fidelity.	Bluetooth has no full-form.
2	Component	Wi-Fi demands a wireless router to set up the connectivity and adapter on the devices.	Bluetooth demands a Bluetooth setting or adapter on all devices to set up connectivity.
3	Power Consumption	It consumes high power.	It consumes low power.
4	Security	WiFi is more secure than Bluetooth.	Bluetooth is less secure than WiFi.
5	Multi User	WiFi can hold a large number of users to be connected.	Bluetooth holds a smaller number of users to be connected.
6	Bandwidth	WiFi requires high bandwidth.	Bluetooth demands low bandwidth.
7	Coverage	WiFi can cover an area up to 32 meters.	Bluetooth can cover an area up to 10 meters.
8	Frequency Range	WiFi frequency range 2.4GHz to 5 GHz	Bluetooth frequency range 2.400 GHz to 2.483 GHz
9	Modulation Technique	In WiFi modulation technique is OFDM(Orthogonal Frequency Division Multiplexing) and QAM(Quadrature Amplitude Modulation).	In Bluetooth modulation technique is GFSK (Gaussian frequency shift keying).
10	Bit-rate	Bit-rate in WiFi is 600 Mbps.	Bit-rate in bluetooth is 2.1 Mbps.
11	IEEE Standards	It’s under IEEE 802.11 Standard	It’s under IEEE 802.15.1
12	Applications	Wifi anaylzer wifi inspector	Consumer Games Industry sport training

Also you can refer : CDMA Digital Cellular Standard