CDMA allows multiple users to share the same channel by assigning each user a unique code. It spreads the user's data signal over a wider bandwidth through multiplication with a pseudo-random code. This allows different signals to be separated at the receiver through correlation with the corresponding code. Major technologies using CDMA include WiFi, Bluetooth, and GPS, which employ techniques like DSSS, FHSS, and long/short codes. Performance of 802.11 networks can be analyzed based on collision probability and throughput calculations under saturated traffic conditions. Later developments expanded CDMA capabilities with techniques like W-CDMA, TD-CDMA, and TD-SCDMA.
SPACE DIVISION MULTIPLE ACCESS (SDMA) SATELLITE COMMUNICATION Soumen Santra
SPACE DIVISION MULTIPLE ACCESS (SDMA)
Definition : The communication channel encountered by this array of antennas.
advanced antenna technology.
Smart Antenna
Uplink Transmission
Downlink Transmission
Block Diagram
Features
Beam Frequency Reuse
Advantages
Disadvantages
Universal mobile telecommunication System (UMTS) is actually the third generation mobile, which uses WCDMA. The Dream was that 2G and 2.5G systems are incompatible around the world.
-Worldwide devices need to have multiple technologies inside of them, i.e. tri-band phones, dual-mode phones
To develop a single standard that would be accepted around the world.
-One device should be able to work anywhere.
Increased data rate.
- Maximum 2048Kbps
UMTS is developed by 3GPP (3 Generation Partnership Project) a joint venture of several organization
3G UMTS is a third-generation (3G): broadband, packet-based transmission of text, digitized voice, video, multimedia at data rates up to 2 Mbps
Also referred to as wideband code division multiple access(WCDMA)
Allows many more applications to be introduce to a worldwide
Also provide new services like alternative billing methods or calling plans.
The higher bandwidth also enables video conferencing or IPTV.
Once UMTS is fully available, computer and phone users can be constantly attached to the Internet wherever they travel and, as they roam, will have the same set of capabilities.
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 .
SPACE DIVISION MULTIPLE ACCESS (SDMA) SATELLITE COMMUNICATION Soumen Santra
SPACE DIVISION MULTIPLE ACCESS (SDMA)
Definition : The communication channel encountered by this array of antennas.
advanced antenna technology.
Smart Antenna
Uplink Transmission
Downlink Transmission
Block Diagram
Features
Beam Frequency Reuse
Advantages
Disadvantages
Universal mobile telecommunication System (UMTS) is actually the third generation mobile, which uses WCDMA. The Dream was that 2G and 2.5G systems are incompatible around the world.
-Worldwide devices need to have multiple technologies inside of them, i.e. tri-band phones, dual-mode phones
To develop a single standard that would be accepted around the world.
-One device should be able to work anywhere.
Increased data rate.
- Maximum 2048Kbps
UMTS is developed by 3GPP (3 Generation Partnership Project) a joint venture of several organization
3G UMTS is a third-generation (3G): broadband, packet-based transmission of text, digitized voice, video, multimedia at data rates up to 2 Mbps
Also referred to as wideband code division multiple access(WCDMA)
Allows many more applications to be introduce to a worldwide
Also provide new services like alternative billing methods or calling plans.
The higher bandwidth also enables video conferencing or IPTV.
Once UMTS is fully available, computer and phone users can be constantly attached to the Internet wherever they travel and, as they roam, will have the same set of capabilities.
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 .
Basic Telecom concepts
Various Wireless Technologies
Cellular concepts & Principal of cellular Comm.
GSM Network Architecture
GSM channel Architecture
Call Flows in GSM
GSM Planning steps (Nominal Plan & RF surveys)
Alternative means of wireless communication
Walkie - Talkie
Pagers
Trunked private radios
Mobile Phone - the magic technology that enables everyone to communicate anywhere with anybody.
Till 1982 Cellular Systems were exclusively Analog Radio Technology.
Advanced Mobile Phone Service (AMPS)
U.S. standard on the 800 MHz Band
Total Access Communication System (TACS)
U.K. standard on 900 MHz band
Nordic Mobile Telephone System (NMT)
Scandinavian standard on the 450 & 900 MHz band
1: Direct sequence and frequency hopped spread spectrum, spreading sequence and their correlation functions, Acquisition and tracking of spread spectrum signals.
2: Error probability for DS-CDMA, on AWGN channels, DS-CDMA on frequency selective fading, channels, Performance analysis of cellular CDMA.
3: Capacity estimation, Power control, effect of imperfect power control on DS CDMA performance, Soft Handoffs.
4: Spreading /coding tradeoffs, multi-carrier CDMA, IS-95 CDMA system, third generation CDMA systems, multi-user detection.
Frequency hoping
Signal broadcast over seemingly random series of frequencies
Direct Sequence
Each bit is represented by multiple bits in transmitted signal
Chipping code
Error Control and performance Analysis of MIMO-OFDM Over Fading ChannelsIOSR Journals
ABSTRACT: Multiple Input Multiple Output is a wireless technology that uses multiple transmitters and
receivers to transfer more data at the same time. Orthogonal Frequency Division Multiplexing, an FDM
modulation technique which splits the signal into multiple smaller sub-signals that are then transmitted
simultaneously at different frequencies to the receiver. OFDM technique spreads the data over number of
carriers which are at specific predefined frequencies. This reduces or eliminates the ISI. Forward error
correction or channel coding is a technique used for controlling errors in data transmission over unreliable or
noisy communication channels. The objective of our proposed paper is to implement the FEC into the MIMO
OFDM systems and its performance is analysed by using MATLAB over different fading channels. For
modulation it employs M-QAM which combines both ASK and PSK thereby enabling several bits to be
transmitted per symbol. The performance of MIMO-OFDM system is evaluated by BER Vs SNR when the bits
propagates through the different fading channels.
Keywords– OFDM, MIMO, QAM, FEC, BER.
OPTICAL SWITCHING CONTROLLER USING FPGA AS A CONTROLLER FOR OCDMA ENCODER SYSTEMEditor IJCATR
This paper proposed a design of optical switching controller using FPGA for OCDMA encoder system. The encoder is one
of the new technologies that use to transmit the coded data in the optical communication system by using FPGA and optical switches.
It is providing a high security for data transmission due to all data will be transmitting in binary code form. The output signals from
FPGA are coded with a binary code that given to an optical switch before it signal modulate with the carrier and transmit to the
receiver. In this paper, AA and 55 data were used for source 1 and source 2. It is generated sample data and sent packet data to the
FPGA and stored it into RAM. The simulation results have done by using software Verilog Spartan 2 programming to simulate. After
that the output will produces at waveform to display the output. The main function of FPGA controlling unit is producing single pulse
and configuring optical switching system.
One of the main challenges faced by the developing (3GPP-LTE-Advanced) standard is providing high throughput at the cell edge.
One solution to improve coverage is the use of fixed relays.
Spread Spectrum TechniquesDescribe in detail a simple data communi.pdfakritigallery
Spread Spectrum Techniques
Describe in detail a simple data communication system that will monitor the temperature of a
remote inaccessible location and display temperature on a personal computer.
Suggest a future application for spread spectrum techniques and explain why SS would be
appropriate for that application.
Solution
Spread spectrum communication systems are widely used today in a variety of applications for
different purposes such as access of same radio interrupted or blocked by spurious transmission
from enemy), interference rejection, spectrum by multiple users (multiple access), anti-jamming
capability (so that signal transmission can not be secure communications, multi-path protection,
etc. However, irrespective of the application, all spread spectrum communication systems satisfy
the following criteria-
a) As the name suggests, bandwidth of the transmitted signal is much greater than that of the
message that modulates a carrier.
b)The power spectral density of the modulated signal is very low and usually comparable to
background noise and interference at the receiver.
DATA COMMUNICATION:
It defines as data exchange between source and receiver.
Wireless Sensor Network (WSN) typically consists of small spatially distributed devices to
cooperatively monitor physical or environmental conditions, such as temperature, sound,
vibration and etc. With WSN connectivity, data from remote sensors of different types are
collected by central unit for further processing and analysis.
WSNs are less expensive and more flexible than wired monitoring systems. There are
applications that become feasible only with WSNs because using wires between devices are too
expensive or impossible at all. For instance, in many industrial, agricultural, military or
ecological problems physical wiring is impossible or would create extreme disturbance for other
operations. WSN, compared to other existing wireless technologies, is the only technology that
targets simple communication with low data rates and low power consumption.
Each WSN node is typically equipped with:
Coding Techniques
In order to transmit anything, codes used for data transmission have to be considered. However,
this section will not discuss the coding of information (like error correction coding) but those
that act as noise-like carriers for the information being transferred. These codes are of much
greater length than those for the usual areas of data transfer, since it is intended for bandwidth
spreading.
Codes in a spread-spectrum system are used for:
Maximal sequencing is one of the more popular coding methods in a spread-spectrum system.
Maximal codes can be generated by a given shift register or a delay element of given length. In
binary shift register sequence generators, the maximum length sequence is (2^n-1) chips, where
n is the number of stages in the shift register.
A shift register generator consists of a shift register in conjunction with the appropriate logic,
which feeds back.
SECURED TEXT MESSAGE TRANSMISSION IN PRE -CHANNEL EQUALIZATION BASED MIMO- OF...IJNSA Journal
In this paper, we made a comprehensive performance evaluative study of a secured MIMO Orthogonal Frequency-Division Multiplexing wireless communication system with implementation of two pre channel equalization techniques such as Pre-Minimum Mean Square Error (Pre-MMSE) and Pre-Zero
Forcing(Pre-ZF) under QPSK and QAM digital modulations. The simulated system deploys three channel coding techniques(1/2-rated Convolutional, CRC and BCH). In the present simulated system, text message transmission has been secured with concatenated implementation of Electronic Codebook (ECB)
and Cipher Feedback(CFB) cryptographic algorithm. It is remarked from simulation results that the MIMO OFDM system outperforms with pre-ZF channel equalization,QAM digital modulation and BCH channel coding schemes under fading channels(AWGN and Raleigh).In Pre-MMSE/pre-ZF channel
equalization scheme, the system shows comparatively worst performance in convolutional channel coding scheme with QAM/QPSK digital modulation. With increase in noise power as compared to signal power, the system is found to have shown performance deterioration
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
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.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
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.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
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.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
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/
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
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
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
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.
7. Code Division Multiple Access Introduction (Cont.): How does it support more than one group in the same channel? It allows multiple groups to share the same channel at the same time by assigning each group to different code. CDMA Modulation Steps: Generate a local pseudo-random code with a higher rate than the data to be transmitted. XOR the data which need to be transmitted with the generated code.
8. Code Division Multiple Access Introduction (Cont.): Data Signal Pseudo-random Code Transmitted Signal Time
9. Code Division Multiple Access Introduction (Cont.): Input data Output data Channel Encoder Modulator Channel Demodulator Channel Decoder Pseudo-noise Generator Pseudo-noise Generator General Model of Spread Spectrum Digital Communication System
33. Code Division Multiple Access Technologies based on CDMA: WiFi (IEEE 802.11): 802.11b and 802.11g working in the 2.4 frequency band (Industry, Science and Medicine band or ISM). DSSS and FHSS physical layer options have been designed specifically to overcome the interfering with other devices in this band.
34. Code Division Multiple Access 22 MHz Channel 6 2.4370 Channel 11 2.4620 Channel 1 2.4120 2.4000 GHz 2.4835 GHz Three Non-Overlapping DSSS Channels in the ISM Band
37. It uses Frequency Hoping Spread Spectrum (FHSS) to make it rare for more than one device to transmit on the same time using the same frequency and to avoid any interference.
38.
39.
40.
41. The satellite carrier frequencies are modulated using the ranging signal which is PRN code which is different between satellites.
42. The receiver uses the satellite PRN code to reconstruct the actual message data.
43.
44. Code Division Multiple Access Performance analysis of IEEE 802.11 protocol: There are several assumptions have been considered in presenting this analytical framework: The effect of bit errors introduced by channel noise has been ignored. The only considered errors are the one which caused by collisions due to other simultaneous transmissions. There are no hidden stations. The propagation delays are not considered. There are n stations in the network.
45. Code Division Multiple Access Performance analysis of IEEE 802.11 protocol (Cont.): Every station always has a packet to send (saturated conditions). The collision probability of a transmitted frame is constant and independent of the number of retransmissions that this frame has experienced in the past. RTS/CTS access mechanism.
46. Code Division Multiple Access Performance analysis of IEEE 802.11 protocol (Cont.): The sequence of events in a successful frame transmission using the RTS/CTS access method will be like the following: RTS: Request To Send. SIFS: Short Inter-Frame Space. CTS: Clear To Send. DIFS: Distributed Coordination Function.
47. Code Division Multiple Access t0 DATA RTS Source Destination SIFS CTS SIFS SIFS ACK Other NAV (RTS) DIFS NAV (CTS) NAV (DATA) Defer Access Back-off RTS: Request To Send. SIFS: Short Inter-Frame Space. CTS: Clear To Send. DIFS: Distributed Coordination Function.
49. Code Division Multiple Access Performance analysis of IEEE 802.11 protocol (Cont.): For simplicity, I assumed that the value of τ will be known and we will start by calculating the value of p: Because we have n stations and all of them will transmit with a probability of τ , then the value of will be:
50. Code Division Multiple Access Performance analysis of IEEE 802.11 protocol (Cont.): The probability of successful transmission will be equal to the probability that one station is transmitting while the remaining stations stay silent: If is the frame header, the average time delays for RTS/CTS will be:
51. Code Division Multiple Access Performance analysis of IEEE 802.11 protocol (Cont.): The throughput will be equal to the time needed to transmit the payload information divided by the average length of slot time: