This document discusses multiple access techniques in wireless communication. It describes several techniques including Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), and Space Division Multiple Access (SDMA). It also covers packet radio access methods like ALOHA, slotted ALOHA, and Carrier Sense Multiple Access (CSMA). Each technique allows multiple users to share wireless spectrum resources simultaneously through dividing access in frequency, time, code, or space.
Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use radio
Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use radio
How to put these nodes together to form a meaningful network.
How a network should function at high-level application scenarios .
On the basis of these scenarios and optimization goals, the design of networking protocols in wireless sensor networks are derived
A proper service interface is required and integration of WSNs into larger network contexts.
What is GSM?
The Global System for Mobile communications is a digital cellular communications system. It was developed in order to create a common European mobile telephone standard but it has been rapidly accepted worldwide.
Formerly it was “Groupe Spéciale Mobile” (founded in 1982)
now: Global System for Mobile Communication.
Services:
Tele-services
Bearer or Data Services
Supplementary services
Applications:
Mobile telephony
GSM-R
Telemetry System
- Fleet management
- Automatic meter reading
- Toll Collection
- Remote control and fault reporting of DG sets
Value Added Services
Advantages:
Better Quality of speech
Data transmission is supported
New services offered due to ISDN compatibility
International Roaming possible
Large market
Crisper, cleaner quieter calls
disadvantages:
Dropped and missed calls
Less Efficiency
Security Issues
conclusion
The mobile telephony industry rapidly growing and that has become backbone for business success and efficiency and a part of modern lifestyles all over the world.
In this session I have tried to give and over view of the GSM system. I hope that I gave the general flavor of GSM and the philosophy behind its design.
The GSM is standard that insures interoperability without stifling competition and innovation among the suppliers to the benefit of the public both in terms of cost and service quality.
The Media Access Control (MAC) data communication protocol sub-layer, also known as the
Medium Access Control, is a sublayer of the Data Link Layer specified in the seven-layer OSI
model (layer 2). The hardware that implements the MAC is referred to as a Medium Access
Controller. The MAC sub-layer 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.
How to put these nodes together to form a meaningful network.
How a network should function at high-level application scenarios .
On the basis of these scenarios and optimization goals, the design of networking protocols in wireless sensor networks are derived
A proper service interface is required and integration of WSNs into larger network contexts.
What is GSM?
The Global System for Mobile communications is a digital cellular communications system. It was developed in order to create a common European mobile telephone standard but it has been rapidly accepted worldwide.
Formerly it was “Groupe Spéciale Mobile” (founded in 1982)
now: Global System for Mobile Communication.
Services:
Tele-services
Bearer or Data Services
Supplementary services
Applications:
Mobile telephony
GSM-R
Telemetry System
- Fleet management
- Automatic meter reading
- Toll Collection
- Remote control and fault reporting of DG sets
Value Added Services
Advantages:
Better Quality of speech
Data transmission is supported
New services offered due to ISDN compatibility
International Roaming possible
Large market
Crisper, cleaner quieter calls
disadvantages:
Dropped and missed calls
Less Efficiency
Security Issues
conclusion
The mobile telephony industry rapidly growing and that has become backbone for business success and efficiency and a part of modern lifestyles all over the world.
In this session I have tried to give and over view of the GSM system. I hope that I gave the general flavor of GSM and the philosophy behind its design.
The GSM is standard that insures interoperability without stifling competition and innovation among the suppliers to the benefit of the public both in terms of cost and service quality.
The Media Access Control (MAC) data communication protocol sub-layer, also known as the
Medium Access Control, is a sublayer of the Data Link Layer specified in the seven-layer OSI
model (layer 2). The hardware that implements the MAC is referred to as a Medium Access
Controller. The MAC sub-layer 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.
Dynamic Power Allocation for Mc-Cdma System Using Iterative Water Filling Alg...inventionjournals
ABSTRACT : Power control in Multi Carrier Code Division Multiple Access ( MCCDMA) based wireless cellular network is of great importance. The power allocation methodology to enhance the performance of the MCCDMA system by limiting interference noise is at the expense of signaling overhead due to sharing of Channel State Information (CSI). The distributed algorithms that manage the power level based on the user’s SINR requirements needs the complete knowledge of Channel State Information (CSI) .Since the CSI is subjected to the errors because of the imperfect channel estimation/measurement due to the time varying nature of the channels, the distributed power control algorithm is not globally optimum. The water filling algorithm is used to allocate proper power for every sub channel in order to improve channel capacity. The water filling algorithm distributes power among all users with the help of SINR that is received by the transmitter instead of getting full Channel State Information (CSI).
optimization of DFA ,compiler design,minimisation of DFA,DFA optimization,equivalence state removal,DFA optimization,partition method for DFA minimization
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
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.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
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.
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
Multiple Access in wireless communication
1. Multiple access in
wireless communication
Subject : Mobile Computing and Wireless Communication
CE-B
Maulik togadiya
2. What is Multiple access?
Multiple access method allows several terminals connected
to the same multi-point transmission medium to transmit
over it. Examples of shared physical media are wireless
networks, bus networks, ring networks and half
duplex point-to-point links.
Multiple access schemes to allow many users to share
simultaneously a finite amount of radio spectrum resources.
2
4. Multiple Access Techniques
Frequency division multiple access (FDMA)
Time division multiple access (TDMA)
Code division multiple access (CDMA)
Space division multiple access (SDMA)
4
5. Frequency division multiple access
(FDMA)
The frequency band is divided into channels of equal
bandwidth so that each conversation is carried on a
different frequency.
A specific frequency band is given to one person, and it
will received by identifying each of the frequency on the
receiving end. It is often used in the first generation of
analog mobile phone.
Each station assigned a fixed frequency.
5
6. In FDMA system signaling dimensions are divided along
the frequency axis into non overlapping channels and
each end users assigned a different frequency channel as
shown in fig.
6
7. Time division multiple access
(TDMA)
Time frame is divided into slots (channels). Each user is
allocated a particular time slot or channel.
Time Division Multiple Access (TDMA) is a digital
cellular telephone communication technology. It facilitates
many users to share the same frequency without
interference. Its technology divides a signal into different
timeslots, and increases the data carrying capacity.
7
8. In TDMA system signaling dimensions are divided along
the Time axis into non overlapping channels and each
end users assigned a different timeslot channel as shown
in fig.
8
9. Code division multiple access
(CDMA)
Code division multiple access (CDMA) is a channel
access method used by various radio communication
technologies.
CDMA is an example of multiple access , where
several transmitters can send information
simultaneously over a single communication channel.
This allows several users to share a band of
frequencies. To permit this without undue interference
between the users, CDMA employs spread-spectrum
technology.
9
10. In this system, a user has access to the whole bandwidth
for the entire duration. The basic principle is that
different CDMA codes are used to distinguish among the
different users.
10
11. Space division multiple access
(CDMA)
If there are no separation in frequency or time or code
domain ,an alternative way of separating different users is
spatial separation
SDMA is a MIMO -based wireless communication network
architecture, primarily suitable for mobile ad-hoc networks,
which enables access to a communication channel by
identifying the user location and establishing a one-to-one
mapping between the network bandwidth division and the
identified spatial location.
11
12. This figure shows a satellite system that uses spatial division
multiple access (SDMA) technology. In this example, a single
satellite contains several directional antennas. Some of these
antennas use the same frequency. This allows a single satellite to
simultaneously communicate to two different satellite receivers that
operate on the same frequency.
12
13. Packet radio access
Packet radio is a form of packet switching technology used
to transmit digital data via radio or wireless
communications links. It uses the same concepts of data
transmission via Datagram that are fundamental to
communications via the Internet.
There are three medium access protocol appropriate for
packet radio networks: ALOHA, slotted ALOHA,
and Carrier Sense Multiple Access (CSMA).
13
14. Pure aloha
In pure ALOHA, the stations transmit frames whenever they have data to
send.
When two or more stations transmit simultaneously, there is collision and
the frames are destroyed.
In pure ALOHA, whenever any station transmits a frame, it expects the
acknowledgement from the receiver.
If acknowledgement is not received within specified time, the station
assumes that the frame (or acknowledgement) has been destroyed.
If the frame is destroyed because of collision the station waits for a
random amount of time and sends it again.
14
15. Therefore pure ALOHA dictates that when time-out period
passes, each station must wait for a random amount of time
before resending its frame. This randomness will help avoid more
collisions.
Figure shows an example of frame collisions in pure ALOHA.
15
16. Slotted aloha
Slotted ALOHA was invented to improve the efficiency of
pure ALOHA as chances of collision in pure ALOHA are very
high.
In slotted ALOHA, the time of the shared channel is divided
into discrete intervals called slots.
The stations can send a frame only at the beginning of the slot
and only one frame is sent in each slot.
In slotted ALOHA, if any station is not able to place the frame
onto the channel at the beginning of the slot i.e. it misses the
time slot then the station has to wait until the beginning of the
next time slot. 16
17. In slotted ALOHA, there is still a possibility of collision if
two stations try to send at the beginning of the same time
slot as shown in fig.
17
18. Carrier sense multiple access
Carrier sense multiple access (CSMA) is a probabilistic
media access control (MAC) protocol in which a node
verifies the absence of other traffic before transmitting on
transmission medium.
CSMA is set of rule that which the device attached to the
network first determine whether the channel or carrier is in
use or free and then act accordingly.
18
19. Type of CSMA:
Persistence CSMA
Non-persistence CSMA
19
20. Multiple access collision avoidance
20
Multiple Access with Collision Avoidance (MACA) is a
protocol for slotted media access control used in wireless
LAN data transmission. MACA is used to avoid data
collisions caused by hidden station problems as well as
simplifying known exposed station problems.
21. In MACA, a wireless network node announces that it is
going to send the data frame, informing the other nodes to
remain silent. When a node intends to transmit the data
frame, it communicates using a signal known as Request-
To-Send (RTS) that includes the length of the data frame
to transmit. If the recipient permits the transmission, it
responds back to the sender with a signal known as Clear-
To-Send (CTS), which includes the length of the data
frame that it is about to receive.
In the meantime, the nodes that listen to the RTS signal
must remain silent until the data is fully transmitted in
order to avoid conflict with CTS.
WLAN data transmission collisions can still happen, and
MACA for Wireless (MACAW) is brought to extend the
functionality of MACA. It demands nodes to send
acknowledgments after every successful frame
transmission.
21