Random Access-Based Protocols Traditional random access MAC-layer protocols, also known as contention-based protocols, require no coordination among the nodes accessing the channel. Colliding nodes back off for a random duration of time before again attempting to access the channel. The enhancement of these protocols with collision avoidance and request-to-send (RTS) and clear-to- send (CTS) mechanisms improves their performance and makes them more robust to the hidden terminal problem The energy efficiency of contention-based MAC-layer protocols, however, remains low due to collisions, idle listening, overhearing, and excessive control overhead. The power aware multicast protocol The power aware multi access protocol with ...
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Definition “A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants, at different locations.” – Wikipedia A very low cost low power computer- on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. It performs tasks, processes data and controls the functionality of other components in the sensor node. Monitors one or more sensors. A Radio Link to the outside world. Are the building blocks of Wireless Sensor Networks (WSN). CPU The Microcontroller ...
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Taxonomy of Protocols The design of the simplest protocol with no flow or error control https://play.google.com/store/apps/details?id=com.pratikkataria.positivityhub Simplest Protocol The sender sends a sequence of frames without even thinking about the receiver. To send three frames, three events occur at the sender site and three events at the receiver site. Note that the data frames are shown by tilted boxes; the height of the box defines the transmission time difference between the first bit and the last bit in the frame. Design of Stop-and-Wait Protocol Stop-and-Wait Protocol The sender sends one frame and waits for feedback from the receiver. When the ...
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Switching Techniques In large networks there might be multiple paths linking sender and receiver. Information may be switched as it travels through various communication channels. There are three typical switching techniques available for digital traffic. Circuit Switching Message Switching Packet Switching Circuit Switching Circuit switching is a technique that directly connects the sender and the receiver in an unbroken path. Telephone switching equipment establishes a path that connects the caller to the receiver by physical connection. Once a connection is established, a dedicated path exists between both ends until the connection is terminated. Routing decisions must be made when the circuit is first established, but ...
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What is Wireless Communication ? Transmitting voice and data using electromagnetic waves in open space (atmosphere) Electromagnetic waves Travel at speed of light (c = 3×108 m/s) Has a frequency (f) and wavelength (LAMBDA) » c = f x LAMBDA Higher frequency means higher energy photons The higher the energy photon the more penetrating is the radiation Types of wireless communication Point-to-Point Communication: Cellular Multipoint Communication: Wireless Computer Network Broadcast Communication: Radio Service Electromagnetic Waves & Electromagnetic Spectrum Transverse waves without a medium! (They can travel through empty space) They travel as vibrations in electrical and magnetic fields. — Have some ...
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VLAN A VLAN allows a network administrator to create groups of logically networked devices that act as if they are on their own independent network, even if they share a common infrastructure with other VLANs. Using VLANs, you can logically segment switched networks based on functions, departments, or project teams. You can also use a VLAN to geographically structure your network to support the growing reliance of companies on home-based workers. These VLANs allow the network administrator to implement access and security policies to particular groups of users. A VLAN is a logically separate IP subnetwork. VLANs allow multiple IP ...
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A cellular network or mobile network is a wireless 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 uses a different set of frequencies from neighboring cells, to avoid interference and provide guaranteed bandwidth within each cell. Cellular Network Devices Cellular Identifiers In Advanced Mobile Phone System (AMPS), a cell phone subscription is identified using three numbers: Electronic Serial Number (ESN): unique 32 bit number programmed into the cell when it was manufactured. Mobile Identification Number (MIN): 10 digit phone ...
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Infrastructure mode & ad-hoc mode All data is transferred using the access point as the central hub. All wireless nodes in an infrastructure mode network connect to an access point. All nodes connecting to the access point must have the same service set identifier (SSID) as the access point, and if the access point is enabled with Wired Equivalent Privacy (WEP) they must have the same WEP key or other authentication parameters. Ad-hoc mode network It is a decentralized type of wireless network.The network is ad hoc because it does not rely on a pre existing infrastructure, such as routers ...
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Bluetooth is a standard developed by a group of electronics manufacturers that will allow any sort of electronic equipment — from computers and cell phones to keyboards and headphones — to make its own connections, without wires, cables or any direct action from a user. A key difference with other existing wireless technologies is that bluetooth enables combined usability models based on functions provided by different devices. The Bluetooth Special Interest Group comprises more than 1000 companies.The major companies who created the technology include Intel 3 com Ericcson IBM Motorola Nokia Toshiba The Name – Bluetooth? The name is attributed ...
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ETHERNET It defines a number of wiring for the physical layer, through means of Network access at the Media Access Control (MAC)/Data Link Layer, and a Common addressing format. The combination of the twisted pair versions of Ethernet with the fiber optic versions largely replacing standards such as coaxial cable Ethernet. In recent years, Wi-Fi, the wireless LAN standardized by IEEE 802.11, has been used instead of Ethernet for many home and small office networks and in addition to Ethernet in larger installations. The Institute of Electrical and Electronics Engineers Standards Association (IEEE- SA) is an organization within IEEE that ...
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