What is plasma display

History :

The plasma display was co-invented in 1964 at the University of Illinois at Urbana Champaign by Donald Bitzer, H.Gene Slottow and Robert Willson for the PLATO computer system. The original monochrome video display panel was very popular in the early 1970s because they were needed freighter memory nor circuitry to refresh the image. In the late 1970s, as semiconductor memory made CRT display cheaper than plasma displays. However, the relatively large screen size and thin body of plasma displays made them suitable for high profile placement in lobbies and stock exchanges. 

In 1983, IBM built in orange-on-black monochrome displayed. Today's display contains a grid of cells in which gas react with phosphors is varying degrees in red, green, or blue sub-pixels, making it possible to produce over 16 million different colors.

1992 - Fujitsu brought in the World's first 21-inch full-color display. 
1994 - Weber explains a color plasma display at an industry convention in San Jose. 
1995 - Fujitsu invented the first 42-inch plasma display. 
2006 - Analyst noted that LCDs overtook plasmas, particularly in 40-inch and above segment. 
2008 - The largest plasma video display in the world at the 2008 Consumer Electronics Show in Las Vegas, Nevada was manufactured by Matsushita Electric Industries. It was a 150 inches. 
2010 - Panasonic introduced their first 3D plasma model 152" 2160p. 

 What is Plasma Display?

 A plasma display is a computer video display in which each pixel on the screen is illuminated by a tiny bit of plasma or charged gas, somewhat like a tiny neon light. They are thinner than cathode ray tube ( CRT ) displays and brighter than LCD called Liquid Crystal Displays. 

Structure of Plasma display :  

A plasma display is made up of many thousands of gas-filled cell that are sandwiched in between (a) two glass plates, (b) two sets electrodes, (C) dielectric material, and  (d) protective layers.

 The address of the electrode is arranged vertically between the rear glass plate and the protective layer. This structure is behind the cells in the rear of the display, with the contact layer in direct contact with the cells.

 On the front side of the display, there are horizontal display electrodes that are in between a magnesium oxide (MgO) protective layer and an insulating dielectric layer. 

 Electrodes in the horizontal and vertical direction form a grid from which each individual cell can be accessed. Each individual cell separated from surrounding cells so that activity in one cell does not affect another.

 The cell structure is similar to a honeycomb structure expect with rectangular cells. To illuminating a particular cell, the electrodes that intersect at the cell are charged by control circuitry and electric current flows through the cell, simulating the gas atoms inside the cell. These ionized gas atoms or plasma's then release ultraviolet photons that interact with a phosphor material on the inside wall of the cell.

 Every pixel on the display is made up of three sub-pixel cells. One sub-pixel cell is coated with red phosphor, another is coated with green phosphor, and the third cell is coated with blue color for the pixel. The control circuitry can manipulate the intensity of light which is emitted from each cell, and therefore can produce a large spectrum of colors. This light from each cell can be controlled and changed rapidly so that produce a high quality moving picture.

 Advantages of plasma display :
  • Can be wall mounted
  • Simple profile 
  • High resolution 
  • Short response time
  • Better motion tracking 
Disadvantages of plasma display :
  • Poor reproduction of black
  • Brightness range is narrower 
  • Consume more electricity
  • Very costly
  • Heavier in weight 

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Difference between CRT display and plasma display

After the digital broadcasting starts everyone will need a digital tuner to receive over-the-air signals. When we upgrade to a digital TV, we will not only get all the great benefits of digital broadcast, including theatre-quality pictures and sound but also have access to additional digital services. so now let us talk about the difference between CRT and Plasma Display.

 CRT technology - CRT uses a beam of electrons to stimulate phosphors and thus electrons to stimulate and thus make the image The beam strikes the phosphor cell at an angle and this creates a large spot size. also, because it is difficult to focus at all points, the image will be less precise in some areas.

 CRT results :

  1. Geometric distortion - The picture on a CRT will always have a certain amount of distortion.
  2. Difficulty focusing across the entire screen - The picture on a CRT will have some regions that are not as focused as others.
  3. Picture distorted by magnetic fields - The CRT electron beam can be influenced by magnetic fields which results in a distorted image.
  4. Uneven light output - The picture on a CRT will have areas that are brighter and areas that are darker than others.
Plasma technology - Each pixel contains 3 cells green, red, and blue. Plasma display panels stimulate phosphor cells individually with electrons. There is no loss of focus.

 Plasma results :
  1. No geometric distortion - The plasma panels' accurate cell structure produces a picture that is geometrically perfect.
  2. Perfect focus -The plasma panel has a perfect focus across the entire screen.
  3. No susceptibility to magnetic fields - The plasma panel is not affected by magnetic fields.
  4. Even light output - The plasma panel is perfectly evenly illuminated so no dark or hot spots.
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Features of FDMA

FDMA is a frequency band is one types of channel access method and can be divided small frequency channel are allocated to different users. The frequency band is divided into channels of equal bandwidth so that each conversation is carried on a different frequency. Now you can check it out some features of FDMA one by one listed below. 

Features of  FDMA

  • The complexity of FDMA systems is less.
  • Every user shares the satellite transponder or frequency channel simultaneously.
  • Demands a highly efficient filter. Require tight filtering to minimize interface. 
  • Continuous transmission method so few bits are required for the overhead purpose.
  • The FDMA channel uses one phone circuit at any instant of time.
  • If the voice channel is assigned in FDMA, then the mobile unit and the base station transmitting simultaneously.
  • The symbol time is large in comparison to the delay spread. 
  • The FDMA system has narrow bandwidth about to 30 kHz as each channel supports only one circuit per carrier.
  • The FDMA mobile unit user duplex as both the transmitter and receiver operate simultaneously.
  • FDMA needs tight RF filtering to minimize the adjacent channel interference.
  • Every user receives an individual frequency because all users transmit and receive at different frequencies.
  • Best suited for analog links. 
  • Usually combined with FDD for duplexing. 

Multiple Access techniques used in wireless communication system

The multiple access techniques with  any of these methods are used for wireless communication, so now let us discuss different multiple access techniques used in the wireless communication system :

  • Global system for mobile (GSM) - TDMA/FDD
  • W-CDMA (3 GPP) - CDMA/FDD, CDMA/TDD
  • Digital European cordless telephones (DECT) - FDMA/TDD
  • CDMA 2000 (3 GPP2) - CDMA/FDD, CDMA/TDD
  • CT2 (cordless telephones) - FDMA/TDD
  • US narrow band spread spectrum (IS 95) - CDMA/FDD


Multiple access techniques in wireless communication

What is Multiple Access?


 The transmission bandwidth in different frequency band varies in range. It is more than the bandwidth needed for a message to be transmitted. Hence, in order to utilized the frequency spectrum efficiency "Multiple Access" method is introduced.

 In telecommunication and computer networks, a channel access method or multiple access methods allow more than two terminals connected to the same transmission medium to transmit over it and to share its capacity. 

 Multiple access technique permits multiple access to a channel. A channel represents a system resource assigned to a given mobile user that enables the user to establish communication with over users in the network. 

 The ability of the system to carry many signals at the same time is called Multiple Access. Through Multiple Access, it is possible to share the communication capacity of the cellular system among a large number of base stations.

 Depending on the channel type, specific multiple access techniques can be used for communication. The channel access types and the associated multiple access techniques are as follows.  

FDMA : 


 FDMA is a wireless system that allows multiple users to send data through a single communication channel, such as a coaxial cable or microwave beam, by dividing the bandwidth of the channel into separate non-overlapping frequency subchannels. Each subchannel allocating to a separate user. 

 The channel or frequency band is unique for each subscriber. The channel allocation can be done on a basis to the users to request service.

In FDMA systems the users are assigned a pair of frequency, one for the forward channel and other for the reverse channel.

 Example - FM radio where multiple users can transmit simultaneously; however, on different frequency channels. 


TDMA : 


 TDMA is a wireless system for shared-medium networks that allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot allows multiple stations to share the same transmission medium while using only a part of its channel capacity. 

 TDMA system divides the radio spectrum into a time slot only one user is allowed to transmit or receive. 

Various users can transmit the same frequency band at different times. 

CDMA : 


CDMA is a wireless system used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel that allows several users to share a band of frequencies.

 In CDMA the narrowband message signal is multiplied by a large bandwidth called spreading signal. This spreading signal is actually a pseudo-noise code sequence and it has a higher chip rate than the data rate of the message signal.

What is analog signal

Signal :


The signal is a physical quantity, which contains some information and which is a function of one or more independent variables.

 The signal can be two types :

 1. Analog signal
 2.Digital signal


What is an Analoge signal?


An analogue single defined as any continuous signal for which the time-varying feature of the signal is a representation of some other time-varying quantity. 

They can have an infinite number of different values. The Analog signal is classified simple and composite signal. 

 An analogue signal is described using amplitude, a period of frequency, and phase. Amplitude mark height of the signal, frequency marks the rate at which the signal is changing and phase marks the position of the wave with respect to time zero.

Let us now discuss some example of the analogue signal.
  1. Temperature
  2. Power
  3. Voltage
  4. Brightness
  5. Sound
  6. Distance
  7. Current
Most of the thing observed in nature are analogue.

What is Satellite

A satellite is any object that moves in a curved path around a planet which has been intentionally placed into orbit. 

Sometimes a satellite orbit looks like an ellipse, a squashed circle that moves around two points known as foci.

The first artificial satellite, launched by Russia in late 1950 was about the size of a basketball. In this satellite, nothing but transmit a simple Morse code signal over and over.

What is Infrared signal

Infrared is a wireless mobile technology used for device communication over short ranges. Infrared is a means of using light to transmit a signal over distance, so LED is used to transmit the IR signal, which passes through a lens and focuses on a beam of IR data.

There are many inexpensive IR systems designed for use TVs, and many theaters use IR to broadcast to the IR equipped headsets that they will loan to patrons who want to hear the movie better.

What is Radio Frequency

Radiofrequency :


Radiofrequency (RF) refers to the rate of oscillation of the electromagnetic radiation spectrum or electromagnetic radio waves. From the frequencies ranging from 3 kHz to 300 GHz, as well as the alternating currents carrying the radio signals. With the use of that communication transmission and broadcasting. 

Radiofrequency is measured in Hertz which represent the number of radio cycle per second when a radio wave is transmitted. Radiofrequency is not visible to the human eye.

Difference between DSP Processor and Microprocessor

A general-purpose microprocessor is not tied to or integrated with a particular language or piece of software. These types of microprocessors are present in personal computers. They are used for computation, text editing, multimedia display, and communication over a network. The DSP processor is a particular type of processor is a specialized microprocessor that has an architecture optimized for the operational needs of digital signal processing. 

 The main difference is that a DSP processor has features designed to support high-performance, repetitive, numerically intensive tasks. DSP processors are designed specifically to perform a large number of complex arithmetic calculations as quickly as possible. As compared to general processors, the DSP processor is more efficient at performing basic arithmetic operations, especially multiplications. 

Difference between the DSP processor and Microprocessor

DSP processor :

  • Instruction cycle - Instruction is executed in a single cycle of the clock.
  • Instruction execution - parallel execution is possible.
  • Suitable for - Array processing operation.
  • Addressing mode - Direct and indirect addressing mode.
  • Computational units - Three separate computational units: ALU, MAC, Sifter.
  • Address generation - Address is generated combine by DAGs and program sequencer. 
  • Program flow control - Program sequencer and instruction register take care of the flow of a program. 
  • Memories - Separate data and program memories.
  • Operand fetch and memory - Multiple operands are fetched simultaneously.
  • On-chip address and data buses - Separate address and data buses for program and data memory i.e DMA, DMD, PMD, PMA, and R bus.
  • Pipelining - Pipelining is implicating through the instruction register and instruction cache. 
  • Address and data bus multiplexing - They are not multiplexed both are separated on-chip as well as off-chip. 
  • Application - Speech processing, audio processing, signal processing, and array processing, etc.

Microprocessor :

  • Instruction cycle - Multiple clock cycle is required for the execution of one instruction.
  • Instruction execution - Execution instruction is always sequential.
  • Suitable for - general-purpose processing.
  • Addressing mode - Direct, indirect register, register indirect, immediate, etc.
  • Computational units - Only main unit: ALU.
  • Address generation - The program counter is incremented sequentially to generate an address.
  • Program flow control - The program counter takes care of the flow of execution.
  • Memories - Normally no such separate memories are present.
  • Operand fetch and memory - Operand is fetched sequentially.
  • On-chip address and data buses - Address and data bus are the two bus on the chip.
  • Pipelining - Queuing performs explicate by one queue register to support pipelining. 
  • Address and data bus multiplexing - Address and data bus are multiplexed. 
  • Application - General purpose applications. 

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Difference between analog and digital signal processing

Analog signal processing is basically any signal processing that is done on the analog signals by analog means. Digital signal processing is basically any signal processing that is done on digital signals or information signals that aim to modify or improve the signal. 

 Analog is mathematically represented as a set of continuous values such as voltage, electric current or electric charge around components in electronic devices. Some example of this type of signal is crossover filters in loudspeakers, bass, treble and volume on stereos, tint on televisions, capacitors, resistors, inductors, and transistors. 

 Digital signal is characterized by a representation of discrete units, such as discrete-time, discrete frequency, or discrete domain signals. It also includes subfields like communication signal processing, radar signal processing, sensor array processing, digital image processing, etc. 

Difference between analog signal processing and digital signal 


 Some key differences between analog signal processing and digital signal processing are listed below. 

Analog Signal Processing :

  • Less versatile
  • Less accuracy
  • Less repeatability
  • Upgradation difficult
  • Difficult to store the analog signal
  • Less system complexity
  • Universal compatibility is not possible
  • Difficult to implement mathematical processing algorithms
  • Require Less power consumption

Digital Signal Processing :

  • More versatile
  • More accuracy
  • More repeatability
  • Upgradation compatibility is possible
  • Such a signal can be easily stored 
  • More system complexity
  • Universal compatibility is possible
  • Mathematical processing algorithm can be easily implemented
  • Require more power consumption

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Difference between GSM and CDMA

GSM is a combination of FDMA and TDMA means that the 100 people who want to communicate can be divided into five groups of 20 each in different rooms where they can communicate in a queue one after another. CDMA is just as name CDMA access technology means that all the 100 people will communicate simultaneously in the same room, but each person will have a unique code to differentiate that person from others. GSM technology is used 2G mobile carrier standards while CDMA is 3G mobile carrier standards. GSM is introduced by industry Consortium and CDMA is introduced by chipmaker Qualcomm. We can check out some features of both GSM and CDMA and then check out the difference between them. 

2G - GSM :

  • Access mode - TDMA/FDD
  • Came about in 1987
  • Carrier - 200 KHz
  • Downlink frequency - 925-960 MHz
  • Uplink frequency - 890-915 MHz
  • Radio interface - TDMA
  • Handoff - Hard handover
  • Frame duration - 4.615 ms
  • Modulation technique - GMSK
  • In 2G GSM time slots in a frame fault rate - 8
  • Technology - 2G
  • Channel bit rate - 270.33 kbps

3G - CDMA :

  • Access mode - CDMA with FDD/TDD
  • Came about in 1957
  • Carrier - 5 MHz
  • Downlink frequency - 2.110-2.170 GHz
  • Uplink frequency - 1.920-1.980 GHz
  • Radio interface - CDMA
  • Handoff - Soft handoff
  • Frame duration- 10 ms
  • Modulation technique - QPSK
  • While in 3G-WCDMA time slots in a frame fault rate - 15
  • Technology - 3G
  • Channel bit rate - 5.76 Mbps

Difference between GSM and CDMA


  • GSM is a digital mobile telephony system whereas CDMA is a channel access method used by various communication technology but both fall under multiple accessing. 
  • GSM is based on a wedge spectrum called a carrier whereas CDMA is based on spread spectrum technology. 
  • In GSM networks, it is much easier to swap phones and CDMA can switch phones with carrier's permission. 
  • GSM provides less security as compared to CDMA. 
  • GSM widely used technology while CDMA restricted to less number of countries. 
  • GSM offers maximum download speed around 384 kbps while CDMA offers maximum download speed around 2 Mbps.
  • GSM phones emit about 28 times more radiations on an average as compared with CDMA. 
  • GSM provides voice and data to be used at the same time, but in CDMA only once can be used at the same time. 
  • GSM is too much older technology while CDMA is advanced technology.
  • GSM and CDMA are both uses a different frequency band.
  • GSM is slowly being phased out in favor of the CDMA.
  • CDMA uses more power while GSM uses low power.
  • CDMA offers much faster data rates, GSM has low data rates.
  • GSM allocates comparatively fewer subscribers than CDMA. 
  • GSM is more reliable and CDMA is less reliable. 
  • GSM used frequency planning to maximize the use of the limited bandwidth whereas CDMA used code planning. 

Zigbee Network | History | Features | Application

Define Zigbee Networks : 


Zigbee is a wireless protocol. It can be used for wireless networking and connectivity is the wireless language that everyday devices use to connect to one another. It is the recently newly emerged technology of network communication based on the IEEE 802.15.4 standard where IEEE stands for Institute of electrical and electronic engineers. It is a new standard developed by the Zigbee alliance for a personal area network consisting of more than 270 companies. 

 Zigbee is a low cost, low power, wireless network standard targeted at battery-powered devices in wireless control, and monitoring application. It is built on the physical layer and media access control defined in IEEE standard 802.15.4 for low rate WPANs. The specification includes four additional components such as network layer, Zigbee Device Objects, and manufactured defined applications objects. 

 The Zigbee network layer supports both star and tree networks, and generic mesh networking. Every network must have one coordinator device. Instar network coordinator must be the central node. Both trees and meshes allow the use of Zigbee routers to extend communication at a network level. 

Zigbee's specification has two implementation options such as Zigbee and Zigbee PRO. 
First implementation Zigbee is designed to support smaller networks with hundreds of devices in a single network. The Zigbee PRO feature set is the most popular device used for most alliance developed standards. It is the first choice of developer.

 This article gives Some basic features of Zigbee networks, advantages and disadvantages and application of Zigbee networks.


History of Zigbee :

  • Zigbee was firstly found in 1998, standardized in 2003 and revised in 2006. 
  • Zigbee style self-organizing ad-hoc digital radio networks were defined in the 1990s. 
  • The IEEE 802.15.4-2003 specification was ratified on 14 December 2004.
  • The Zigbee Alliance announced the availability of specification 1.0 on 13 June 2005. 
  • Zigbee PRO also is known as Zigbee 2007 was finalized in 2007.

A feature of Zigbee networks :

  • It incorporates power saving mechanisms for all device classes
  • Discovery mechanism with full application confirmation
  • pairing mechanism with full application confirmation
  • various transmission option included broadcast
  • Uses small packet compared with WiFi and Bluetooth
  • Low data rate
  • Low battery consumption
  • The maximum operating range for Zigbee device is 250 feet
  • Easy to implement
  • Low cost
  • Support up to 65000 nodes connected in a Zigbee network
  • Zigbee can automatically establish its network

Application of Zigbee networks :

  • Home automation :
    1. Heating, lighting
    2. Cooling, door locking mechanisms
    3. Home security system
    4. Smoke detector
  • Telecom application :
    1. Used to transmit and receive the message
    2. Share ring tone, images and contacts also
    3. Emergency services
  • Industrial automation
    1. Personal tracking
    2. Livestock tracking
    3. Record and transmit critical data like vibration, pressure, and temperature
  • Security : 
    1. Home security
    2. Fire detection
  • Health care
  • Smart energy
  • Remote control for consumer electronics 
  • Hotel room access
  • Smart metering

Simulation of Zigbee Network :


Simulation of a network like ns2, OMNeT++, OPNET, and NetSim can be used to simulate IEEE 802.15.4 Zigbee networks. 

All simulators we can see above come with open source C or C++ libraries for users to modify. This is the way that users can determine the validity of new algorithms before hardware implementation. 

Difference between 3G and Wi-Fi

3G and Wi-Fi are both wireless access technologies operating in different frequencies and access ranges. You can access the internet with 3G and Wi-Fi. Wi-Fi only can go up to 250 meters and 3G coverage could go beyond Kilometers. Wi-Fi is a personal wireless LAN used in short-range with low setup fees whereas 3G is normally deployed by Mobile operators in voice and wireless broadband networks. Wi-Fi operated in high frequency thus data rate is high so Wi-Fi is much faster than 3G. Now in this article, you can check it out the difference between 3G and Wi-Fi both Internet access providers. 

 The main difference between them is speed.

Difference between 3G and WiFi 

  1. Controlled by: Wi-Fi access is controlled by a Wi-Fi router located at a distance from an access point and 3G is completely controlled and provided by a service provider. 
  2. Signals: Signals of Wi-Fi can be received if the user is present within a range of the router whereas singles of 3G can be received within the network coverage area. 
  3. Network: 3G basically evolved from a voice network where QoS is a critical success factor while Wi-Fi evolved from a data network where QoS is not a critical success factor. 
  4. Licensed: 3G uses licensed spectrum for the device while Wi-Fi uses unlicensed, free, share spectrum.
  5. Infrastructure: 3G service providers own and manage the infrastructure and customers have a monthly service provider while the Wi-Fi user organization owns the infrastructure and also the usage of a network does not involve an access fee.
  6. Coverage: 3G has a much larger coverage than Wi-Fi networks.
  7. Cost: The use of Wi-Fi technology is considered to be less expensive as compared to third-generation (3G) technology.
  8. Reliability: The 3G network is more reliable than the Wi-Fi network.
  9. 3G is basically used Voice over IP ( VoIP ) to download software and content, news, download music, personal communication network, etc while Wi-Fi uses offices/campuses, homes, railway stations, airports, factory shop floors, etc.
  10. Speed: 3G can go up to a maximum speed of 14 Mbits/s and Wi-Fi can go up to 54 Mbits/s. So as compare to 3G networks, Wi-Fi networks are too much faster.
  11. Stability: 3G frequency is comparatively less stable than WIFI, WIFI frequencies are more stable than 3Gb frequency. 
  12. Installation: Wi-Fi can be easily installed by anyone by setting up a wireless LAN on a computer that has a wireless adapter installed and 3G can only be installed by network provider companies.
  13. Frequency: The frequencies of 3G network are less secured, but the WIFI frequencies are faster and more secure. 
  14. Pay: There is need to pay to connect to the 3G network, Whereas there is no need to pay to connect to a WIFI network. 
  15. Radio Frequency: 3G transmits data at low  frequencies ranging from 850 MHZ to 1900 MHz WIFI transmit data at 2.4 GHz and 5 GHZ frequencies. 
  16. Used: 4G has replaced th 3G network, but Wi-Fi is more used nowadays. 
  17. Cover: 3G covers a long range usually kilometers, whereas WIFI covers a short range. 
  18. Support: 3G supports both data and voice, WIFI just support data. 
  19. Dependability: 3G is more dependable than WIFI, While WIFI is less dependable than 3G. 
However, looking at their similarities and difference, in a nutshell, we can say that both 3G and Wi-Fi have been contributing to the growing telecommunication sector and proved to be very important for Internet and mobile telephone services. 

 Explore more information:
  1. Difference between Bluetooth and WiMAX
  2. Difference between 3G and 4G 
  3. Difference between 1G, 2G, 3G, and 4G technology
  4. Difference between Zigbee and WiFi
  5. Difference between Wi-Fi and WiMax
  6. Difference between Wi-Fi and Bluetooth
  7. Difference between Wi-Fi and Internet
  8. Difference between Li-Fi and Wi-Fi
  9. Difference between GiFi and WiFi
  10. Difference between WiFi and MiFi
  11. Difference between ethernet and WiFi

Full form of MMDS

What is the full form of MMDS?


 Answer :

  • Multi-Channel Multi-point Distributed Service


What does MMDS mean?


MMDS was formerly known as Broadband Radio Service ( BRS ) also known as a wireless cable is a wireless telecommunications technology, used for general-purpose broadband networking or, more commonly, as an alternative method of television programming reception. 

 MMDS may be outdated by the newer 802.16 WiMax standard approved since 2004. 

 MMDS provided a significantly greater range than LMDS. 

The FCC has assigned five hands of frequency in the US in the range from 2.15 GHz to 2.68 GHz for fixed wireless access that uses multichannel multipoint service.

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Difference between Bluetooth and WiMAX

Bluetooth devices and WiMAX devices both are wireless technologies that communicate with each other and also have to interconnect with each other.

Basically, the main difference between them is that Bluetooth is primarily used to connect devices without using cables, whereas WiMAX is Worldwide Inter-portability for Microwave Access.

Bluetooth :

  • Technology - Radio
  • Multiplexing - FHSS, OFDM, DSSS
  • Range - 10 m
  • Frame Size - 350 bytes
  • Speed - 1 to 4 Mbps
  • Frequency Range - 2.4 GHz
  • Media Access - Distributed/central CSMA/CA, MACAW
  • Application using Bluetooth - Microwave ovens, DVD players, cameras, banking, office, etc

WiMAX :

  • Technology - Microwave
  • Multiplexing - FDD, TDD
  • Range - 10 Km in air
  • Frame Size - 5 to 20 ms
  • Speed - Up to 75 Mbps
  • Frequency Range - 2-66 GHz
  • Media Access - OFDMA
  • Application using WiMAX - Healthcare, travellers, small business, wireless ISP, home/residential areas etc

Difference between TCP and UDP

TCP's full meaning Transmission Control Protocol is connection-oriented, whereas UDP full meaning User Datagram Protocol is connection-less. 

Connection-orientation is that the communicating devices should establish a connection before transmitting data and should close the connection after transmitting the data. Datagram protocol means there is no overhead for opening a connection, maintaining a connection, and terminating a connection. 

Difference between TCP and UDP 

  • There is an acknowledgment for each byte so we called TCP a byte-stream protocol on the other side with no acknowledgment in UDP. 
  • Because of Acknowledgments, TCP is considered a reliable data transfer protocol while UDP is unreliable.
  • TCP is heavyweight whereas UDP is lightweight. 
  • The header size of TCP is 20 bytes and the UDP header size is 8 bytes. 
  • Retransmission of lost packets is possible in TCP, but not possible in UDP. 
  • Segment sequencing of data is a feature of TCP and no such feature for UDP. 
  • Because of an upper feature, TCP gives a guarantee that the order of data at receiving end is the same as on sending end whereas UDP has no such guarantee.
  • TCP is used by HTTP, HTTPs, FTP, SMTP and Telnet, and UDP is used by DNS, DHCP, TFTP, SNMP, RIP, and VOIP. 
  • TCP requires much more computer resources while UDP requires less computer resources.
  • UDP is much faster than TCP.
  • UDP is faster in data transferring than TCP.
  • TCP supports full-duplex while UDP not.
  • TCP is safer than UDP.
  • Flow control, congestion control happen in TCP while UPD both are not happening.  
  • TCP arranges data packet in an order specified while UDP protocol no inherent ordering, the data packets of the same message may be ordered differently.
  • TCP makes a check for error and reporting while UDP makes error checking but no reporting.
  • TCP follows 3 way of handshakes for connection establishment whereas no handshake is required in UDP since it is connectionless protocol. 
  • Example of TCP: Making a phone call Example of UDP: Playing online games. 
Handshake of TCP : 
  1. SYN
  2. SYN-ACK
  3. ACK
Field of TCP : 
  1. Sequence number 
  2. AcK number 
  3. Data offset 
  4. Reserved 
  5. Control bit 
  6. Window
  7. Urgent Pointer 
  8. Options
  9. Padding
  10. Checksum 
  11. Source port 
  12. Destination Port 
Field of UDP : 
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