Frequency hopping spread spectrum (FH-SS) is a type of spread spectrum technique where the available channel bandwidth is divided into a large number of frequency slots arranged continuously. A transmitted signal occupies one or more of the available frequency slots, with the frequencies selected pseudo-randomly based on the output of a pseudo-noise generator. There are two types of FH-SS: slow FH-SS where one or more data bits are transmitted within one hop, and fast FH-SS where one data bit is divided over multiple hops. FH-SS provides advantages like improved interference rejection, code division multiplexing for CDMA, secure communication, and increased capacity and spectral efficiency. It is used in military communication systems, satellite communication,
Spread spectrum is a communication technique that spreads a narrowband communication signal over a wide range of frequencies for transmission then de-spreads it into the original data bandwidth at the receive.
Spread spectrum is a communication technique that spreads a narrowband communication signal over a wide range of frequencies for transmission then de-spreads it into the original data bandwidth at the receive.
This presentation covers:
Some basic definitions & concepts of digital communication
What is Phase Shift Keying(PSK) ?
Binary Phase Shift Keying – BPSK
BPSK transmitter & receiver
Advantages & Disadvantages of BPSK
Pi/4 – QPSK
Pi/4 – QPSK transmitter & receiver
Advantages of Pi/4- QPSK
This presentation covers:
Some basic definitions & concepts of digital communication
What is Phase Shift Keying(PSK) ?
Binary Phase Shift Keying – BPSK
BPSK transmitter & receiver
Advantages & Disadvantages of BPSK
Pi/4 – QPSK
Pi/4 – QPSK transmitter & receiver
Advantages of Pi/4- QPSK
It is the repeated switching of frequencies during radio transmission, often to minimize the effectiveness of "electronic warfare" - that is, the unauthorized interception or jamming of telecommunications.
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.
Presentation on 1G/2G/3G/4G/5G/Cellular & Wireless TechnologiesKaushal Kaith
This Presentation is explaining all about the Generations of Mobile or Cellular Technology (1G/2G/2.5/ 3G/4g/5G). This explain the invented details ,features,drawbacks,look of wireless models and comparison and evolution of technology from 1G to 5G and also explaining about wireless application and their services.
Data Communications,Data Networks,computer communications,multiplexing,spread spectrum,protocol architecture,data link protocols,signal encoding techniques,transmission media
These slides cover a topic on Spread spectrum in Data Communication. All the slides are explained in a very simple manner. It is useful for engineering students & also for the candidates who want to master data communication & computer networking.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Implementation of Direct Sequence Spread Spectrum Communication System Using ...IJAEMSJORNAL
This paper presents the designed and implementation of spread spectrum technology for data transfer to overcome the interference problems associated with narrow band, very high frequency and ultra high frequency data transfer systems. The spread spectrum communication is used to reduce jamming of communication and provides a heightened secure communication. In this paper, the design and analyzes are implemented by Field Programmable Gate Array (FPGA) for baseband spread spectrum communication system using Pseudo Noise Sequences (PNS) for spreading digital data. The sequence generator and direct sequence spread spectrum (DSSS) for a single user is implemented in a FPGA module. The generated pseudo noise sequences are investigated for autocorrelation, cross correlation and balance properties. The bit error rates performance of the system is evaluated in multiuser environment under AWGN and reveals that, the DSSS system using pseudo noise sequences as spreading sequences significantly outperforms for the conventional PN sequences system
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2. The term – “Spread Spectrum”
IN TELECOMMUNICATION AND RADIO
COMMUNICATION, SPREAD SPECTRUM TECHNIQUES
ARE METHODS BY WHICH A SIGNAL GENERATED
WITH A PARTICULAR BANDWIDTH IS DELIBERATELY
SPREAD IN THE FREQUENCY DOMAIN, RESULTING IN
A SIGNAL WITH A WIDER BANDWIDTH.
….SAYS WIKIPEDIA
3. “Spread Spectrum” – In Simple Words
A MODULATION TECHNIQUE WHEREBY A
MODULATED WAVEFORM IS MODULATED SECOND
TIME IN SUCH A WAY SO AS TO GENERATE AN
EXPANDED BANDWIDTH (WIDEBAND) SIGNAL, THAT
DOES NOT SIGNIFICANTLY INTERFERE WITH OTHER
SIGNALS.
4. Need of Spread Spectrum Technique
TO PROVIDE EFFICIENT UTILIZATION OF BANDWIDTH
AND POWER.
TO REJECT INTERFERENCE.
TO ESTABLISH SECURE COMMUNICATION.
6. Types Of Spread Spectrum
DIRECT SEQUENCE SPREAD SPECTRUM TECHNIQUE (DS-SS)
FREQUENCY HOP SPREAD SPECTRUM TECHNIQUE (FH-SS)
CARRIER SERVICE MULTIPLE ACCESS SPREAD SPECTRUM
(CSMA)
TIME HOPING
HYBRID SPREAD SPECTRUM
7. Insight Into – “FH-SS”
THE AVAILABLE CHANNEL BANDWIDTH IS DIVIDED
INTO A LARGE NUMBER.
ARRANGED IN CONTINOUS FRQUENCY SLOTS.
TRANSMITTED SIGNAL OCCUPIES ONE OR MORE OF
THE AVAILABLE FRQUENCY SLOT.
FREQUENCY SLOTS ARE SELECTED “PSEUDO
RANDOMLY”
BASED ON THE OUTPUT OF THE PN GENERATOR.
11. Pseudo Noise Generator
USED TO SPREAD THE BANDWIDTH OF THE MODULATED
SIGNAL TO THE LARGER TRANSMISSION BANDWIDTH.
12. Types of FH-SS
THERE ARE TWO TYPES OF FREQUENCY HOPPING:
1. SLOW FREQUENCY HOPPING SPREAD SPECTRUM
2. FAST FREQUENCY HOPPING SPREAD SPECTRUM
13. Difference between Slow & Fast FH-SS
SLOW FAST
In this case one or more data bits
are transmitted within one Hop.
One data bit is divided over
multiple Hops.
Coherent data detection is
possible.
Coherent signal detection is
difficult, and seldom used.
Error controlling can be done No Error controlling
14. Advantages
IMPROVED INTERFERENCE REJECTION
CODE DIVISION MULTIPLEXING FOR CDMA
SECURE COMMUNICATION
HIGH RESOLUTION RANGING
INCREASED CAPACITY AND SPECTRAL EFFICIENCY
LOWER COST OF IMPLEMENTATION
READILY AVAILABLE IC COMPONENTS
15. FH-SS – “Uses”
IN MILITARY COMMUNICATION SYSTEMS.
- UNAUTHORISED RECEIVERS CANNOT DETECT
MESSAGE.
- MILITARY RADIOS USES CRYPTOGRAPHIC
TECHNIQUES TO GENERATE THE CHANNEL
SEQUENCE.
- TRANSMISSION SECURITY KEY (TRANSEC)
IN SATELLITE COMMUNICATION
IN LOCAL AREA NETWORKS (LAN)