This document summarizes Carrier Sense Multiple Access (CSMA) techniques for digital data communication systems. It describes four CSMA access modes: 1-Persistent, Non-Persistent, P-Persistent, and O-Persistent. It also discusses CSMA protocol modifications like CSMA with Collision Detection (CSMA/CD), CSMA with Collision Avoidance (CSMA/CA), and Virtual Time CSMA (VTCSMA). Applications of different CSMA techniques are provided. At the end, it mentions including a MATLAB code sample for CSMA/CD.
Carrier-sense multiple access with collision detection (CSMA/CD) is a media access control method used most notably in early Ethernet technology for local area networking.Carrier-sense multiple access with collision detection is a media access control method used most notably in early Ethernet technology for local area networking. It uses carrier-sensing to defer transmissions until no other stations are transmitting.
Carrier-sense multiple access with collision detection (CSMA/CD) is a media access control method used most notably in early Ethernet technology for local area networking.Carrier-sense multiple access with collision detection is a media access control method used most notably in early Ethernet technology for local area networking. It uses carrier-sensing to defer transmissions until no other stations are transmitting.
In the seven-layer OSI model of computer networking, media access control (MAC) data communication protocol is a sublayer of the data link layer (layer 2). The MAC sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, e.g. an Ethernet network. The hardware that implements the MAC is referred to as a media access controller.
The MAC sublayer acts as an interface between the logical link control (LLC) sublayer and the network's physical layer. The MAC layer emulates a full-duplex logical communication channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.
Channelization is a multiple-access method in which the available bandwidth of a link is shared in time, frequency, or through code, between different stations. The three channelization protocols are FDMA, TDMA, and CDMA
Carrier-sense multiple access with collision avoidance. It is a networking presentation.Here describe how CSMA/CA works to avoid collision.It helps a beginner student to understand who its work.
Carrier Sense Multiple Access With Collision Detection (CSMA/CD) Details : Me...Soumen Santra
Media Access Protocol (MAC)
Carrier Sense Multiple Access With Collision Detection (CSMA/CD)
Definition
Introduction
Features
Principle
Flowchart
Collision Mechanism
COLLISION DETECTION METHODS
Slot Time
Non-Persistent CSMA/CD
Efficiency
Advantages
Disadvantages
Detail Discussion with Mathematical Formula
In the seven-layer OSI model of computer networking, media access control (MAC) data communication protocol is a sublayer of the data link layer (layer 2). The MAC sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, e.g. an Ethernet network. The hardware that implements the MAC is referred to as a media access controller.
The MAC sublayer acts as an interface between the logical link control (LLC) sublayer and the network's physical layer. The MAC layer emulates a full-duplex logical communication channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.
Channelization is a multiple-access method in which the available bandwidth of a link is shared in time, frequency, or through code, between different stations. The three channelization protocols are FDMA, TDMA, and CDMA
Carrier-sense multiple access with collision avoidance. It is a networking presentation.Here describe how CSMA/CA works to avoid collision.It helps a beginner student to understand who its work.
Carrier Sense Multiple Access With Collision Detection (CSMA/CD) Details : Me...Soumen Santra
Media Access Protocol (MAC)
Carrier Sense Multiple Access With Collision Detection (CSMA/CD)
Definition
Introduction
Features
Principle
Flowchart
Collision Mechanism
COLLISION DETECTION METHODS
Slot Time
Non-Persistent CSMA/CD
Efficiency
Advantages
Disadvantages
Detail Discussion with Mathematical Formula
An e-market, or electronic market, is a virtual marketplace where buyers and sellers can engage in transactions through the use of digital platforms, such as websites, mobile apps, or social media. E-markets have become increasingly popular in recent years due to their convenience, accessibility, and global reach.
E-markets differ from traditional markets in several ways:
Global reach: E-markets have a global reach, allowing buyers and sellers to connect from anywhere in the world. This means that businesses can access new markets and reach customers that they may not have been able to reach through traditional channels.
Convenience: E-markets offer a high degree of convenience, allowing customers to shop from the comfort of their homes or on the go using mobile devices. This convenience factor can lead to higher customer satisfaction and loyalty.
Lower overhead costs: E-markets typically have lower overhead costs than traditional markets, as they do not require physical storefronts, inventory storage, or other infrastructure. This can result in lower prices for customers and higher profit margins for businesses.
24/7 availability: E-markets are available 24/7, allowing customers to shop at any time of the day or night. This can be particularly advantageous for businesses that operate in multiple time zones or that cater to customers with varying schedules.
Greater competition: E-markets can be highly competitive, with many businesses vying for the attention and loyalty of customers. This can result in lower prices, higher quality products, and better customer service as businesses compete for market share.
Introduction to Location-based Applications
GSM- and GPS-based Positioning Control
Ericsson Mobile Positioning System (MPS)
Network-based Positioning Estimation Control
Signal Strength
Angle of Arrival (AOA)
Timing Advance (TA), CGI+TA
Uplink Time of Arrival (UL-TOA)
Uplink Time Difference of Arrival (U-TDOA)
MS-based Positioning Estimation Control
Enhanced Observed Time Difference (E-OTD)
Assisted GPS (A-GPS)
Architecture of MPS
E911
What is noise?
White noise
Impulsive noise
Active noise Cancellation
Car is a noisy environment: noise level between 65 and 75 db
Adaptive Noise Cancellation
Adaptive filter
Algorithms used to adjust the coefficients of the digital filter
Radio Access Network Functions
Radio Access Network Responsibilities
Antenna Configuration Requirements
RF Antenna Planning
Nominal Radio Plan For Kocaeli University
Introduction Videos about LTE AP Pro
Overview on LTE and 4.5 G Evolution Around the World
LTE Advance Pro: Enhancements
LTE Advance Pro: New Use Cases
Case Study: Turkey’s Mobile Operators Evolution towards 4.5 G
Summary of LTE Advance Pro
MATLAB Simulation: 2D Beamforming algorithms (LMS, NLMS RLS and CM)
References
Introduction to Convolutional Codes
Convolutional Encoder Structure
Convolutional Encoder Representation(Vector, Polynomial, State Diagram and Trellis Representations )
Maximum Likelihood Decoder
Viterbi Algorithm
MATLAB Simulation
Hard and Soft Decisions
Bit Error Rate Tradeoff
Consumed Time Tradeoff
Kinds of Propagation Models
Models of Different Types of Cells
Web Plot Digitizer Tool
Study of the parameters fc, d, hb, hm and Coverage Environments for each of OKUMURA, HATA and COST231
MATLAB Simulation
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
1. BTM509 Digital Data Communication Systems
KOCAELI UNIVERSITY
Graduate School of
Natural and Applied Sciences
Prepared By: Mohammed ABUIBAID
Email: m.a.abuibaid@gmail.com
Submitted to: Dr. Halil YİĞİT
Electronic and Communication Engineering
Carrier Sense Multiple Access
AcademicYear
2015/2016
3. Introduction video
CSMA Access Modes
- 1-Persistent
- Non-Persistent
- P-Persistent
- O-Persistent
CSMA Protocol Modifications
- CSMA with collision detection
- CSMA with collision avoidance
- Virtual time CSMA
CSMA/CD & CSMA/CA made simple – Youtube
4. CSMA access modes
1-Persistent : an aggressive transmission algorithm
Non-Persistent : a non aggressive transmission algorithm
P-Persistent : an approach between 1-persistent and non-persistent
O-Persistent: Each node is assigned a transmission order by a supervisory node
5. 1-Persistent CSMA access mode
In case of a collision, the sender waits for a random period of time and attempts
to transmit again unconditionally (i.e. with probability=1).
1-persistent CSMA is used in CSMA/CD systems including Ethernet.
6. Non-Persistent CSMA access mode
This approach reduces collision, results in overall higher medium throughput
but with a penalty of longer initial delay compared to 1–persistent.
7. P-Persistent CSMA access mode
P-Persistent CSMA is used in CSMA/CA
systems including Wi-Fi and other
packet radio systems.
8. Each node is assigned a transmission order by a supervisory node.
When the transmission medium goes idle, nodes wait for their time slot in
accordance with their assigned transmission order.
The node assigned to transmit first transmits immediately.
The node assigned to transmit second waits one time slot (but by that time the first node
has already started transmitting).
Nodes monitor the medium for transmissions from other nodes and update their
assigned order with each detected transmission (i.e. they move one position closer to the
front of the queue).
O-Persistent CSMA access mode
9. O-Persistent CSMA access mode
O-Persistent CSMA is used by CobraNet, LonWorks and the controller area network.
It is used for the automation of various functions
within buildings such as lighting and HVAC, …etc.
It is used in large audio installations such as
convention centers, stadiums, airports, … etc.
10. CSMA Protocol Modifications:
CSMA/CD: improves CSMA performance by terminating transmission as soon
as a collision is detected.
CSMA/CA: improves CSMA performance by reducing the incidence of collision.
VTCSMA : improves CSMA performance by avoiding collision generated by
nodes transmitting signals simultaneously.
12. CSMA/CD Applications
CSMA/CD was used in now obsolete shared media Ethernet variants
(10BASE5, 10BASE2) and in the early versions of twisted-pair Ethernet
which used repeater hubs.
10BASE2
13. CSMA/CD Applications
Modern Ethernet networks, built with switches and full-duplex
connections, no longer need to utilize CSMA/CD because each collision
domain is now isolated.
CSMA/CD is still supported for
backwards compatibility and for
half-duplex connections.
14. CSMA with Collision Avoidance
Collisions are avoided by three
strategies:
Inter-frame space
The contention window
Acknowledgments
16. VTCSMA : Virtual time CSMA
Designed to avoid collision generated by nodes transmitting signals simultaneously.
It used mostly in hard real-time systems (such as mission-critical applications)
It uses two clocks at every node, a virtual clock VC and a real clock RC which tells "real time".
When the transmission medium is sensed to be busy, the VC freezes.
When the transmission medium is free, VC is reset.
Calculating VC runs faster than RC when channel is free
VC is not initiated when the transmission medium is busy.
1-persistent CSMA is an aggressive transmission algorithm.
When the transmitting node is ready to transmit, it senses the transmission medium for idle or busy.
If idle, then it transmits immediately.
If busy, then it senses the transmission medium continuously until it becomes idle, then transmits the message (a frame) unconditionally (i.e. with probability=1).
Non persistent CSMA is a non aggressive transmission algorithm.
When the transmitting node is ready to transmit data, it senses the transmission medium for idle or busy.
If idle, then it transmits immediately.
If busy, then it waits for a random period of time (during which it does not sense the transmission medium) before repeating the whole logic cycle (which started with sensing the transmission medium for idle or busy) again.
This is an approach between 1-persistent and non-persistent CSMA access modes.
When the transmitting node is ready to transmit data, it senses the transmission medium for idle or busy.
If idle, then it transmits immediately.
If busy, then it senses the transmission medium continuously until it becomes idle, then transmits a frame with probability p.
If the node does not transmit (the probability of this event is 1-p), it waits until the next available time slot.
If the transmission medium is still not busy, it transmits again with the same probability p.
This probabilistic hold-off repeats until the frame is finally transmitted or when the medium is found to become busy again (i.e. some other node has already started transmitting).
In the latter case the node repeats the whole logic cycle (which started with sensing the transmission medium for idle or busy) again.
Procedure: It is complete when the frame is transmitted successfully or a collision is detected during transmission.
Is my frame ready for transmission? If yes, it goes on to the next point.
Is medium idle? If not, wait until it becomes ready
Start transmitting and monitor for collision during transmission
Did a collision occur? If so, go to collision detected procedure.
Reset retransmission counters and end frame transmission.
Collision detected procedure: It is complete when retransmission is initiated or the retransmission is aborted due to numerous collisions.
Continue transmission (with a jam signal instead of frame header/data/CRC) until minimum packet time is reached to ensure that all receivers detect the collision
Increment retransmission counter
Was the maximum number of transmission attempts reached? If so, abort transmission.
Calculate and wait random backoff period based on number of collisions.
Re-enter main procedure at stage 1.
The jam signal or jamming signal is a signal that carries a 32-bit binary pattern sent by a data station to inform the other stations of the collision and that they must not transmit.
Request to Send/Clear to Send (RTS/CTS) may optionally be used at this point to mediate access to the shared medium.
The Access Point only issues a Clear to Send to one node at a time.
Transmission: if the medium was identified as being clear or the node received a CTS to explicitly indicate it can send, it sends the frame in its entirety.
Unlike CSMA/CD, it is very challenging for a wireless node to listen at the same time as it transmits.
Continuing the wireless example, the node awaits receipt of an acknowledgement packet from the Access Point to indicate the packet was received and check summed correctly.
If such acknowledgement does not arrive after a timely manner, it assumes the packet collided with some other transmission, causing the node to enter a period of binary exponential backoff prior to attempting to re-transmit.
GNET: an early proprietary LAN protocol.
NCR WaveLAN - an early proprietary wireless network protocol.
G.hn: G.9960 which provides a way to create a high-speed (up to 1 Gigabit/s) local area network using existing home wiring (power lines, phone lines and coaxial cables).