The document discusses multiple access protocols for wireless networks. It describes random access methods like ALOHA, CSMA, and CSMA/CA. It also covers controlled access methods using reservation, polling, and token passing. Finally, it examines channelization techniques for dividing bandwidth like FDMA, TDMA, and CDMA. It provides examples checking properties of orthogonal codes used in CDMA.
Frequency modulation (FM) varies the frequency of the carrier signal based on the modulating signal. FM has better fidelity and noise immunity than amplitude modulation (AM). It uses constant carrier amplitude, requiring less complex circuitry than AM. However, FM uses more spectrum space than AM. A modulated FM signal has constant amplitude but varying frequency. Its instantaneous frequency and phase deviation are proportional to the modulating signal. The modulation index indicates the ratio of frequency deviation to modulating frequency. Bessel functions describe the spectrum of an FM signal and relative amplitudes of its carrier and sidebands.
This document provides an overview of data communication systems and their key components and concepts. It discusses the basic components of a data communication system including messages, senders, receivers, transmission medium, and protocols. It then describes various concepts such as line configuration (point-to-point and multipoint), network topologies (bus, star, ring, mesh), transmission modes (simplex, half-duplex, full-duplex), and modems. The document focuses on explaining these fundamental building blocks and concepts to understand how data is transmitted between devices.
This document discusses various data communication techniques including packetization, multiplexing, and switching. It describes how data is divided into packets with header information added. It explains different types of multiplexing including frequency division, time division, and statistical time division. It also covers circuit switching versus packet switching and different error control techniques such as parity checks, checksums, and cyclic redundancy checks used to detect errors.
Basic Concepts in Data Communication DC1koolkampus
This document discusses different network topologies and transmission modes. It includes figures and descriptions of point-to-point and multipoint line configurations as well as mesh, star, tree, bus, ring and hybrid network topologies. Transmission modes such as simplex, half-duplex, and full-duplex are also examined.
The document is a presentation submitted by Harpreet Kaur on data communications. It contains information on various topics related to data communications including an introduction to data communication, components of data communication such as sender, receiver, message, transmission medium and protocol. It also discusses data flow modes, analog and digital signals, types of transmission media including guided media such as coaxial cable, twisted pair cable and fiber optic cable, and unguided media. Finally, it covers networking devices such as modem, hub, switch and router.
The document discusses various aspects of data communication. It explains how modems convert digital data to analog signals to transmit over standard telephone lines, and how different digital connections like ISDN, DSL, and cable modems transmit data at higher speeds. It also describes wireless communication technologies like WiFi, WiMAX, and how they enable local and wide area networking using radio waves. Diagrams provide simple illustrations of data communication systems using these various modes of transmission.
Ethernet was first created by Robert Metcalfe and standardized by IEEE as 802.3. Fast Ethernet (802.3u) transmitted data 10 times faster than standard Ethernet at 100 Mbps while still being backward compatible. Gigabit Ethernet (802.3z) further increased speed to 1000 Mbps and supported full duplex between computers and switches or half duplex between computers and hubs using CSMA/CD. Switched Ethernet uses switches containing plug-in cards to reduce collisions by separating collision domains and allowing parallel transmission between cards.
A computer network allows multiple computers to be interconnected via transmission paths like telephone lines. Data communication is the exchange of digital data between two devices via a transmission medium like wires. There are two types of data communication: local, for communicating devices in the same building, and remote, for devices farther apart. A data communication system must effectively deliver data to the correct destination, do so accurately, and deliver it in a timely manner. The five basic components of data communication are: the message being communicated, the sender, the receiver, the transmission medium connecting them, and the communication protocols governing the exchange.
Carrier Ethernet provides standardized, carrier-class Ethernet services on a global scale. It builds upon Metro Ethernet by expanding the services to cover worldwide networks traversing multiple countries and access networks. Carrier Ethernet is defined by five key attributes that distinguish it from traditional LAN-based Ethernet: it provides standardized services across multiple networks; can scale to support millions of nodes and high bandwidths; offers reliable service with fast protection from link failures; ensures quality of service through service level agreements; and manages services through centralized operations support systems.
Pure (unslotted) ALOHA is simpler since packets are not required to transmit at the beginning of time slots, increasing the probability of collisions. The probability of successful transmission by a given node is equal to the probability the node transmits multiplied by the probability no other nodes transmit within the same time period. For slotted ALOHA, time is divided into equal length time slots and nodes transmit packets at the beginning of the next slot. If a collision occurs, packets will be retransmitted with probability p until successful. Slotted ALOHA can achieve higher efficiency, with the optimal transmission probability p approaching 1/e = 0.37 as the number of nodes increases, resulting in a maximum throughput of 37%
This document discusses multiple access protocols for wireless networks. It begins by describing random access protocols like ALOHA and slotted ALOHA. It then covers controlled access protocols using reservation, polling, and token passing. Finally, it discusses channelization protocols using frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). Throughout are examples calculating throughput for different access loads and determining minimum frame sizes.
Data communication and network Chapter -1Zafar Ayub
This document discusses data communication and networks. It defines data communication as the electronic transmission of digitally encoded information between networks via a medium. A network is defined as hardware, software, and protocols that allow sharing of resources and information according to set rules. The document also defines several key terms related to data communication and networks such as data, resources, channels, protocols, encryption, network hardware and software, senders, and receivers. It describes methods of data transmission including serial and parallel transmission.
CSMA/CD is a media access control method used in early Ethernet technology that uses carrier sensing to detect other signals while transmitting. It improves on CSMA by terminating transmission as soon as a collision is detected to shorten the time before resending. There are three types of CSMA protocols: 1-Persistent, Non-Persistent, and P-Persistent. CSMA/CD networks can detect collisions within twice the propagation delay allowing aborted collisions. It was used in older Ethernet variants and is still supported for backwards compatibility.
This document provides an introduction to data communications and networks. It discusses key topics such as data representation, data flow, characteristics of data communication like delivery and accuracy. It describes different network types including LAN, WAN, MAN. Network topologies like star, bus, ring and hybrid are explained. Protocols define rules for communication regarding what, how and when to communicate. Standards are agreed upon rules and are developed by standards organizations.
The document discusses multiple access protocols for wireless networks. It describes random access methods like ALOHA, CSMA, and CSMA/CA. It also covers controlled access methods using reservation, polling, and token passing. Finally, it examines channelization techniques for dividing bandwidth like FDMA, TDMA, and CDMA. It provides examples checking properties of orthogonal codes used in CDMA.
Frequency modulation (FM) varies the frequency of the carrier signal based on the modulating signal. FM has better fidelity and noise immunity than amplitude modulation (AM). It uses constant carrier amplitude, requiring less complex circuitry than AM. However, FM uses more spectrum space than AM. A modulated FM signal has constant amplitude but varying frequency. Its instantaneous frequency and phase deviation are proportional to the modulating signal. The modulation index indicates the ratio of frequency deviation to modulating frequency. Bessel functions describe the spectrum of an FM signal and relative amplitudes of its carrier and sidebands.
This document provides an overview of data communication systems and their key components and concepts. It discusses the basic components of a data communication system including messages, senders, receivers, transmission medium, and protocols. It then describes various concepts such as line configuration (point-to-point and multipoint), network topologies (bus, star, ring, mesh), transmission modes (simplex, half-duplex, full-duplex), and modems. The document focuses on explaining these fundamental building blocks and concepts to understand how data is transmitted between devices.
This document discusses various data communication techniques including packetization, multiplexing, and switching. It describes how data is divided into packets with header information added. It explains different types of multiplexing including frequency division, time division, and statistical time division. It also covers circuit switching versus packet switching and different error control techniques such as parity checks, checksums, and cyclic redundancy checks used to detect errors.
Basic Concepts in Data Communication DC1koolkampus
This document discusses different network topologies and transmission modes. It includes figures and descriptions of point-to-point and multipoint line configurations as well as mesh, star, tree, bus, ring and hybrid network topologies. Transmission modes such as simplex, half-duplex, and full-duplex are also examined.
The document is a presentation submitted by Harpreet Kaur on data communications. It contains information on various topics related to data communications including an introduction to data communication, components of data communication such as sender, receiver, message, transmission medium and protocol. It also discusses data flow modes, analog and digital signals, types of transmission media including guided media such as coaxial cable, twisted pair cable and fiber optic cable, and unguided media. Finally, it covers networking devices such as modem, hub, switch and router.
The document discusses various aspects of data communication. It explains how modems convert digital data to analog signals to transmit over standard telephone lines, and how different digital connections like ISDN, DSL, and cable modems transmit data at higher speeds. It also describes wireless communication technologies like WiFi, WiMAX, and how they enable local and wide area networking using radio waves. Diagrams provide simple illustrations of data communication systems using these various modes of transmission.
Ethernet was first created by Robert Metcalfe and standardized by IEEE as 802.3. Fast Ethernet (802.3u) transmitted data 10 times faster than standard Ethernet at 100 Mbps while still being backward compatible. Gigabit Ethernet (802.3z) further increased speed to 1000 Mbps and supported full duplex between computers and switches or half duplex between computers and hubs using CSMA/CD. Switched Ethernet uses switches containing plug-in cards to reduce collisions by separating collision domains and allowing parallel transmission between cards.
A computer network allows multiple computers to be interconnected via transmission paths like telephone lines. Data communication is the exchange of digital data between two devices via a transmission medium like wires. There are two types of data communication: local, for communicating devices in the same building, and remote, for devices farther apart. A data communication system must effectively deliver data to the correct destination, do so accurately, and deliver it in a timely manner. The five basic components of data communication are: the message being communicated, the sender, the receiver, the transmission medium connecting them, and the communication protocols governing the exchange.
Carrier Ethernet provides standardized, carrier-class Ethernet services on a global scale. It builds upon Metro Ethernet by expanding the services to cover worldwide networks traversing multiple countries and access networks. Carrier Ethernet is defined by five key attributes that distinguish it from traditional LAN-based Ethernet: it provides standardized services across multiple networks; can scale to support millions of nodes and high bandwidths; offers reliable service with fast protection from link failures; ensures quality of service through service level agreements; and manages services through centralized operations support systems.
Pure (unslotted) ALOHA is simpler since packets are not required to transmit at the beginning of time slots, increasing the probability of collisions. The probability of successful transmission by a given node is equal to the probability the node transmits multiplied by the probability no other nodes transmit within the same time period. For slotted ALOHA, time is divided into equal length time slots and nodes transmit packets at the beginning of the next slot. If a collision occurs, packets will be retransmitted with probability p until successful. Slotted ALOHA can achieve higher efficiency, with the optimal transmission probability p approaching 1/e = 0.37 as the number of nodes increases, resulting in a maximum throughput of 37%
This document discusses multiple access protocols for wireless networks. It begins by describing random access protocols like ALOHA and slotted ALOHA. It then covers controlled access protocols using reservation, polling, and token passing. Finally, it discusses channelization protocols using frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). Throughout are examples calculating throughput for different access loads and determining minimum frame sizes.
Data communication and network Chapter -1Zafar Ayub
This document discusses data communication and networks. It defines data communication as the electronic transmission of digitally encoded information between networks via a medium. A network is defined as hardware, software, and protocols that allow sharing of resources and information according to set rules. The document also defines several key terms related to data communication and networks such as data, resources, channels, protocols, encryption, network hardware and software, senders, and receivers. It describes methods of data transmission including serial and parallel transmission.
CSMA/CD is a media access control method used in early Ethernet technology that uses carrier sensing to detect other signals while transmitting. It improves on CSMA by terminating transmission as soon as a collision is detected to shorten the time before resending. There are three types of CSMA protocols: 1-Persistent, Non-Persistent, and P-Persistent. CSMA/CD networks can detect collisions within twice the propagation delay allowing aborted collisions. It was used in older Ethernet variants and is still supported for backwards compatibility.
This document provides an introduction to data communications and networks. It discusses key topics such as data representation, data flow, characteristics of data communication like delivery and accuracy. It describes different network types including LAN, WAN, MAN. Network topologies like star, bus, ring and hybrid are explained. Protocols define rules for communication regarding what, how and when to communicate. Standards are agreed upon rules and are developed by standards organizations.
1) Frequency modulation (FM) varies the instantaneous frequency of the carrier signal in proportion to an input modulating signal. This produces sidebands around the carrier frequency.
2) FM is considered superior to amplitude modulation (AM) due to better fidelity, noise immunity, and transmission efficiency. However, FM requires more bandwidth than AM.
3) The modulation index determines the number of significant sidebands and bandwidth occupied. It is defined as the peak frequency deviation divided by the modulating signal frequency.
Fast Ethernet increased the bandwidth of standard Ethernet from 10 Mbps to 100 Mbps. It used the same CSMA/CD access method and frame format as standard Ethernet but with some changes to address the higher speed. Fast Ethernet was implemented over twisted pair cables using 100BASE-TX or over fiber optic cables using 100BASE-FX. The increased speed enabled Fast Ethernet to compete with other high-speed LAN technologies of the time like FDDI.