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.
RANDOM ACCESS PROTOCOL IN COMMUNICATION AMOGHA A K
In random access ,each station has right to send the data. However , if more than one station tries to send ,collision will occur .To avoid this collision , protocols came into existence.
In random access method , no stations are superior & none is assigned the control over the other .
When a station has a data to send , it uses a procedure defined by a protocol whether to send or not .
RANDOM ACCESS PROTOCOL IN COMMUNICATION AMOGHA A K
In random access ,each station has right to send the data. However , if more than one station tries to send ,collision will occur .To avoid this collision , protocols came into existence.
In random access method , no stations are superior & none is assigned the control over the other .
When a station has a data to send , it uses a procedure defined by a protocol whether to send or not .
Asynchronous Transfer Mode ATM is the cell relay protocol designed by ATM Forum and adopted by the ITU-T. Cell, a small fixed size block of information with asynchronous TDM ensures high speed real time transmission with efficient and cheaper technology. Instead of user addresses, it uses virtual circuit identifier and virtual path identifier, which can be repeated at unrelated locations. This technology ensures connectivity to much more users than normal packet switching networks.
ATM and ISDN-B combination allows high-speed interconnection of world's network.
routing table ,What is routing ? , what is static routing , what is dynamic routing , types of routing , routing protocols , routing strategy , Download Routing pdf , Download routing ppt , download routing notes , paper on routing
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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
The most fundamental digital modulation techniques are based on keying: PSK (phase-shift keying): a finite number of phases are used. FSK (frequency-shift keying): a finite number of frequencies are used. ... QAM (quadrature amplitude modulation): a finite number of at least two phases and at least two amplitudes are used.
Asynchronous Transfer Mode ATM is the cell relay protocol designed by ATM Forum and adopted by the ITU-T. Cell, a small fixed size block of information with asynchronous TDM ensures high speed real time transmission with efficient and cheaper technology. Instead of user addresses, it uses virtual circuit identifier and virtual path identifier, which can be repeated at unrelated locations. This technology ensures connectivity to much more users than normal packet switching networks.
ATM and ISDN-B combination allows high-speed interconnection of world's network.
routing table ,What is routing ? , what is static routing , what is dynamic routing , types of routing , routing protocols , routing strategy , Download Routing pdf , Download routing ppt , download routing notes , paper on routing
To Download Complete Documentation Visit My Blog
http://studyofcs.blogspot.com/2015/06/what-is-routerwhat-is-routing.html
Download completer BS Computer Science Degree Study Data
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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
The most fundamental digital modulation techniques are based on keying: PSK (phase-shift keying): a finite number of phases are used. FSK (frequency-shift keying): a finite number of frequencies are used. ... QAM (quadrature amplitude modulation): a finite number of at least two phases and at least two amplitudes are used.
This slide describe the techniques of digital modulation and Bandwidth Efficiency:
The first null bandwidth of M-ary PSK signals decrease as M increases while Rb is held constant.
Therefore, as the value of M increases, the bandwidth efficiency also increases.
CSMA/CD (Carrier Sense Multiple Access/ Collision Detection) is a media access control method that was widely used in Early Ethernet technology/LANs when there used to be shared Bus Topology and each node ( Computers) were connected By Coaxial Cables. Now a Days Ethernet is Full Duplex and Topology is either Star (connected via Switch or Router) or Point to Point ( Direct Connection). Hence CSMA/CD is not used but they are still supported though.
Consider a scenario where there are ‘n’ stations on a link and all are waiting to transfer data through that channel. In this case, all ‘n’ stations would want to access the link/channel to transfer their own data. Problem arises when more than one station transmits the data at the moment. In this case, there will be collisions in the data from different stations.
CSMA/CD is one such technique where different stations that follow this protocol agree on some terms and collision detection measures for effective transmission. This protocol decides which station will transmit when so that data reaches the destination without corruption.
How CSMA/CD works?
Step 1: Check if the sender is ready for transmitting data packets.
Step 2: Check if the transmission link is idle?
Sender has to keep on checking if the transmission link/medium is idle. For this, it continuously senses transmissions from other nodes. Sender sends dummy data on the link. If it does not receive any collision signal, this means the link is idle at the moment. If it senses that the carrier is free and there are no collisions, it sends the data. Otherwise, it refrains from sending data.
Step 3: Transmit the data & check for collisions.
Sender transmits its data on the link. CSMA/CD does not use an ‘acknowledgment’ system. It checks for successful and unsuccessful transmissions through collision signals. During transmission, if a collision signal is received by the node, transmission is stopped. The station then transmits a jam signal onto the link and waits for random time intervals before it resends the frame. After some random time, it again attempts to transfer the data and repeats the above process.
Step 4: If no collision was detected in propagation, the sender completes its frame transmission and resets the counters.
How does a station know if its data collide?
Consider the above situation. Two stations, A & B.
Propagation Time: Tp = 1 hr ( Signal takes 1 hr to go from A to B)
At time t=0, A transmits its data.
t= 30 mins : Collision occurs.
After the collision occurs, a collision signal is generated and sent to both A & B to inform the stations about a collision. Since the collision happened midway, the collision signal also takes 30 minutes to reach A & B.
Therefore, t=1 hr: A & B receive collision signals.
This collision signal is received by all the stations on that link. Then,
How to ensure that it is our station’s data that collided?
For this, Transmission time (Tt) > Propagation Time (Tp) [Rough boun
Memristor-Capacitor Based Startup Circuit for Voltage Reference Generatorsmangal das
This paper presents the design of Memristorcapacitor based startup circuit. Memristor is a novel device and has many advantages over conventional CMOS devices such as no leakage current and is easy to manufacture. In this work the switching characteristics of memristor is utilized. First the
theoretical equations describing the switching behavior of memristor are derived. To prove the switching capabilities of Memristor, a startup circuit based on series combination of Memristor-capacitor is proposed. This circuit is compared with the reference circuit (which utilizes resistor in place of memristor) and the previously reported MOSFET based startup circuits. Comparison of different circuits was done to validate the results. Simulation results shows that memristor based circuit attains on (I = 2.25 mA) to off state (I = 10 μA) in 2.8 ns while the MOSFET based startup circuits takes (I = 1 mA) to off state (I = 10 μA) in 55.56 ns. However no significant difference in switching time was observed when compared with resistance based startup circuit. The benefit comes in terms of area because much larger die area is required for manufacturing of resistance in comparison to fabrication of memristor.
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"mangalforyou@gmail.com" : i belive in sharing the knowledge so please send project reports ,seminar and ppt. to me .
you can be friend with me on orkut
"mangalforyou@gmail.com" : i belive in sharing the knowledge so please send project reports ,seminar and ppt. to me .
you can be friend with me on orkut
"mangalforyou@gmail.com" : i belive in sharing the knowledge so please send project reports ,seminar and ppt. to me .
you can be friend with me on orkut
"mangalforyou@gmail.com" : i belive in sharing the knowledge so please send project reports ,seminar and ppt. to me .
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
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The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
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Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
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• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
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• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
I have heard many times that architecture is not important for the front-end. Also, many times I have seen how developers implement features on the front-end just following the standard rules for a framework and think that this is enough to successfully launch the project, and then the project fails. How to prevent this and what approach to choose? I have launched dozens of complex projects and during the talk we will analyze which approaches have worked for me and which have not.
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Let's dive deeper into the world of ODC! Ricardo Alves (OutSystems) will join us to tell all about the new Data Fabric. After that, Sezen de Bruijn (OutSystems) will get into the details on how to best design a sturdy architecture within ODC.
2. Figure 12.1 Data link layer divided into two functionality-oriented sublayers
3. Figure 12.2 Taxonomy of multiple-access protocols discussed in this chapter
4. 12-1 RANDOM ACCESS In random access or contention methods, no station is superior to another station and none is assigned the control over another. No station permits, or does not permit, another station to send. At each instance, a station that has data to send uses a procedure defined by the protocol to make a decision on whether or not to send. ALOHA Carrier Sense Multiple Access Carrier Sense Multiple Access with Collision Detection Carrier Sense Multiple Access with Collision Avoidance Topics discussed in this section:
7. The stations on a wireless ALOHA network are a maximum of 600 km apart. If we assume that signals propagate at 3 × 10 8 m/s, we find T p = (600 × 10 3 ) / (3 × 10 8 ) = 2 ms. Now we can find the value of T B for different values of K . a . For K = 1, the range is {0, 1}. The station needs to| generate a random number with a value of 0 or 1. This means that T B is either 0 ms (0 × 2) or 2 ms (1 × 2), based on the outcome of the random variable. Example 12.1
8. b. For K = 2, the range is {0, 1, 2, 3}. This means that T B can be 0, 2, 4, or 6 ms, based on the outcome of the random variable. c. For K = 3, the range is {0, 1, 2, 3, 4, 5, 6, 7}. This means that T B can be 0, 2, 4, . . . , 14 ms, based on the outcome of the random variable. d. We need to mention that if K > 10, it is normally set to 10. Example 12.1 (continued)
9. Figure 12.5 Vulnerable time for pure ALOHA protocol
10. A pure ALOHA network transmits 200-bit frames on a shared channel of 200 kbps. What is the requirement to make this frame collision-free? Example 12.2 Solution Average frame transmission time T fr is 200 bits/200 kbps or 1 ms. The vulnerable time is 2 × 1 ms = 2 ms. This means no station should send later than 1 ms before this station starts transmission and no station should start sending during the one 1-ms period that this station is sending.
11. The throughput for pure ALOHA is S = G × e −2G . The maximum throughput S max = 0.184 when G= (1/2). Note
12. A pure ALOHA network transmits 200-bit frames on a shared channel of 200 kbps. What is the throughput if the system (all stations together) produces a. 1000 frames per second b. 500 frames per second c. 250 frames per second. Example 12.3 Solution The frame transmission time is 200/200 kbps or 1 ms. a. If the system creates 1000 frames per second, this is 1 frame per millisecond. The load is 1. In this case S = G× e −2 G or S = 0.135 (13.5 percent). This means that the throughput is 1000 × 0.135 = 135 frames. Only 135 frames out of 1000 will probably survive.
13. Example 12.3 (continued) b. If the system creates 500 frames per second, this is (1/2) frame per millisecond. The load is (1/2). In this case S = G × e −2G or S = 0.184 (18.4 percent). This means that the throughput is 500 × 0.184 = 92 and that only 92 frames out of 500 will probably survive. Note that this is the maximum throughput case, percentagewise. c. If the system creates 250 frames per second, this is (1/4) frame per millisecond. The load is (1/4). In this case S = G × e − 2G or S = 0.152 (15.2 percent). This means that the throughput is 250 × 0.152 = 38. Only 38 frames out of 250 will probably survive.
15. The throughput for slotted ALOHA is S = G × e −G . The maximum throughput S max = 0.368 when G = 1. Note
16. Figure 12.7 Vulnerable time for slotted ALOHA protocol
17. A slotted ALOHA network transmits 200-bit frames on a shared channel of 200 kbps. What is the throughput if the system (all stations together) produces a. 1000 frames per second b. 500 frames per second c. 250 frames per second. Example 12.4 Solution The frame transmission time is 200/200 kbps or 1 ms. a. If the system creates 1000 frames per second, this is 1 frame per millisecond. The load is 1. In this case S = G× e −G or S = 0.368 (36.8 percent). This means that the throughput is 1000 × 0.0368 = 368 frames. Only 386 frames out of 1000 will probably survive.
18. Example 12.4 (continued) b. If the system creates 500 frames per second, this is (1/2) frame per millisecond. The load is (1/2). In this case S = G × e −G or S = 0.303 (30.3 percent). This means that the throughput is 500 × 0.0303 = 151. Only 151 frames out of 500 will probably survive. c. If the system creates 250 frames per second, this is (1/4) frame per millisecond. The load is (1/4). In this case S = G × e −G or S = 0.195 (19.5 percent). This means that the throughput is 250 × 0.195 = 49. Only 49 frames out of 250 will probably survive.
19. Figure 12.8 Space/time model of the collision in CSMA B C
25. A network using CSMA/CD has a bandwidth of 10 Mbps. If the maximum propagation time (including the delays in the devices and ignoring the time needed to send a jamming signal, as we see later) is 25.6 μs, what is the minimum size of the frame? Example 12.5 Solution The frame transmission time is T fr = 2 × T p = 51.2 μs. This means, in the worst case, a station needs to transmit for a period of 51.2 μs to detect the collision. The minimum size of the frame is 10 Mbps × 51.2 μs = 512 bits or 64 bytes. This is actually the minimum size of the frame for Standard Ethernet.
29. In CSMA/CA, the IFS can also be used to define the priority of a station or a frame. Note
30. In CSMA/CA, if the station finds the channel busy, it does not restart the timer of the contention window; it stops the timer and restarts it when the channel becomes idle. Note
32. 12-2 CONTROLLED ACCESS In controlled access , the stations consult one another to find which station has the right to send. A station cannot send unless it has been authorized by other stations. We discuss three popular controlled-access methods. Reservation Polling Token Passing Topics discussed in this section:
34. Figure 12.19 Select and poll functions in polling access method
35. Figure 12.20 Logical ring and physical topology in token-passing access method
36. 12-3 CHANNELIZATION 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. In this section, we discuss three channelization protocols. Frequency-Division Multiple Access (FDMA) Time-Division Multiple Access (TDMA) Code-Division Multiple Access (CDMA) Topics discussed in this section:
37. We see the application of all these methods in Chapter 16 when we discuss cellular phone systems. Note
47. Figure 12.27 Digital signal created by four stations in CDMA
48. Figure 12.28 Decoding of the composite signal for one in CDMA
49. Figure 12.29 General rule and examples of creating Walsh tables
50. The number of sequences in a Walsh table needs to be N = 2 m . Note
51. Find the chips for a network with a. Two stations b. Four stations Example 12.6 Solution We can use the rows of W 2 and W 4 in Figure 12.29: a. For a two-station network, we have [+1 +1] and [+1 −1]. b . For a four-station network we have [+1 +1 +1 +1], [+1 −1 +1 −1], [+1 +1 −1 −1], and [+1 −1 −1 +1].
52. What is the number of sequences if we have 90 stations in our network? Example 12.7 Solution The number of sequences needs to be 2 m . We need to choose m = 7 and N = 2 7 or 128. We can then use 90 of the sequences as the chips.
53. Prove that a receiving station can get the data sent by a specific sender if it multiplies the entire data on the channel by the sender’s chip code and then divides it by the number of stations. Example 12.8 Solution Let us prove this for the first station, using our previous four-station example. We can say that the data on the channel D = (d 1 ⋅ c 1 + d 2 ⋅ c 2 + d 3 ⋅ c 3 + d 4 ⋅ c 4 ). The receiver which wants to get the data sent by station 1 multiplies these data by c 1 .