Multiple access techniques allow multiple mobile users to share limited spectrum resources simultaneously. The main techniques are frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). In FDMA, each user is assigned a unique pair of frequencies. In TDMA, the total bandwidth is divided into time slots that users transmit in turn. In CDMA, all users transmit over the same frequency but are separated by unique codes. Each technique has advantages and disadvantages regarding complexity, bandwidth utilization, and vulnerability to interference.
Successful interference cancellation with Blind Equalization method for MC-CD...IJTET Journal
Abstract— The increasing demand for wireless services has created the need for cost effective transmission techniques that can exploit scarce spectral resources efficiently. Inorder to achieve the high data rates needed to meet the quality of service requirements of future multimedia applications, MC-CDMA has been considered as good air-interface candidate, especially for the downlink. However, the user capacity of MC-CDMA system is essentially limited by interference. This interference can be mitigated by employing precoding techniques, IB-DFE based receivers and other efficient interference suppression techniques. In the proposed system, combined Iterative IA precoding at the transmitter with IB-DFE based processing at the receiver is suggested for MC-CDMA systems. The matrices for this nonlinear space-frequency equalizer are obtained by minimizing the overall MSE of all data streams at each subcarrier.
Presentation on MULTIPLE ACCESS TECHNIQUES FOR WIRELESS COMMUNICATION By SUPRIYA BHARATI (ME/EC/10006/16) and KHUSHBOO KUMARI (ME/EC/10010/16) Under the Guidance of Dr. Sanjay Kumar Department of Electronics & Communication Engg. (ECE) Birla Institute of Technology, Mesra ,Ranchi-835215 , Jharkhand , India
The tutorial is designed for all those readers who are planning or pursuing the CDMA course to make their career in this field. However, it is also meant for the common readers who simply want to understand − what is CDMA Technology?
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.
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).
Tata Group Dials Taiwan for Its Chipmaking Ambition in Gujarat’s DholeraAvirahi City Dholera
The Tata Group, a titan of Indian industry, is making waves with its advanced talks with Taiwanese chipmakers Powerchip Semiconductor Manufacturing Corporation (PSMC) and UMC Group. The goal? Establishing a cutting-edge semiconductor fabrication unit (fab) in Dholera, Gujarat. This isn’t just any project; it’s a potential game changer for India’s chipmaking aspirations and a boon for investors seeking promising residential projects in dholera sir.
Visit : https://www.avirahi.com/blog/tata-group-dials-taiwan-for-its-chipmaking-ambition-in-gujarats-dholera/
Successful interference cancellation with Blind Equalization method for MC-CD...IJTET Journal
Abstract— The increasing demand for wireless services has created the need for cost effective transmission techniques that can exploit scarce spectral resources efficiently. Inorder to achieve the high data rates needed to meet the quality of service requirements of future multimedia applications, MC-CDMA has been considered as good air-interface candidate, especially for the downlink. However, the user capacity of MC-CDMA system is essentially limited by interference. This interference can be mitigated by employing precoding techniques, IB-DFE based receivers and other efficient interference suppression techniques. In the proposed system, combined Iterative IA precoding at the transmitter with IB-DFE based processing at the receiver is suggested for MC-CDMA systems. The matrices for this nonlinear space-frequency equalizer are obtained by minimizing the overall MSE of all data streams at each subcarrier.
Presentation on MULTIPLE ACCESS TECHNIQUES FOR WIRELESS COMMUNICATION By SUPRIYA BHARATI (ME/EC/10006/16) and KHUSHBOO KUMARI (ME/EC/10010/16) Under the Guidance of Dr. Sanjay Kumar Department of Electronics & Communication Engg. (ECE) Birla Institute of Technology, Mesra ,Ranchi-835215 , Jharkhand , India
The tutorial is designed for all those readers who are planning or pursuing the CDMA course to make their career in this field. However, it is also meant for the common readers who simply want to understand − what is CDMA Technology?
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.
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).
Tata Group Dials Taiwan for Its Chipmaking Ambition in Gujarat’s DholeraAvirahi City Dholera
The Tata Group, a titan of Indian industry, is making waves with its advanced talks with Taiwanese chipmakers Powerchip Semiconductor Manufacturing Corporation (PSMC) and UMC Group. The goal? Establishing a cutting-edge semiconductor fabrication unit (fab) in Dholera, Gujarat. This isn’t just any project; it’s a potential game changer for India’s chipmaking aspirations and a boon for investors seeking promising residential projects in dholera sir.
Visit : https://www.avirahi.com/blog/tata-group-dials-taiwan-for-its-chipmaking-ambition-in-gujarats-dholera/
[Note: This is a partial preview. To download this presentation, visit:
https://www.oeconsulting.com.sg/training-presentations]
Sustainability has become an increasingly critical topic as the world recognizes the need to protect our planet and its resources for future generations. Sustainability means meeting our current needs without compromising the ability of future generations to meet theirs. It involves long-term planning and consideration of the consequences of our actions. The goal is to create strategies that ensure the long-term viability of People, Planet, and Profit.
Leading companies such as Nike, Toyota, and Siemens are prioritizing sustainable innovation in their business models, setting an example for others to follow. In this Sustainability training presentation, you will learn key concepts, principles, and practices of sustainability applicable across industries. This training aims to create awareness and educate employees, senior executives, consultants, and other key stakeholders, including investors, policymakers, and supply chain partners, on the importance and implementation of sustainability.
LEARNING OBJECTIVES
1. Develop a comprehensive understanding of the fundamental principles and concepts that form the foundation of sustainability within corporate environments.
2. Explore the sustainability implementation model, focusing on effective measures and reporting strategies to track and communicate sustainability efforts.
3. Identify and define best practices and critical success factors essential for achieving sustainability goals within organizations.
CONTENTS
1. Introduction and Key Concepts of Sustainability
2. Principles and Practices of Sustainability
3. Measures and Reporting in Sustainability
4. Sustainability Implementation & Best Practices
To download the complete presentation, visit: https://www.oeconsulting.com.sg/training-presentations
Putting the SPARK into Virtual Training.pptxCynthia Clay
This 60-minute webinar, sponsored by Adobe, was delivered for the Training Mag Network. It explored the five elements of SPARK: Storytelling, Purpose, Action, Relationships, and Kudos. Knowing how to tell a well-structured story is key to building long-term memory. Stating a clear purpose that doesn't take away from the discovery learning process is critical. Ensuring that people move from theory to practical application is imperative. Creating strong social learning is the key to commitment and engagement. Validating and affirming participants' comments is the way to create a positive learning environment.
LA HUG - Video Testimonials with Chynna Morgan - June 2024Lital Barkan
Have you ever heard that user-generated content or video testimonials can take your brand to the next level? We will explore how you can effectively use video testimonials to leverage and boost your sales, content strategy, and increase your CRM data.🤯
We will dig deeper into:
1. How to capture video testimonials that convert from your audience 🎥
2. How to leverage your testimonials to boost your sales 💲
3. How you can capture more CRM data to understand your audience better through video testimonials. 📊
Attending a job Interview for B1 and B2 Englsih learnersErika906060
It is a sample of an interview for a business english class for pre-intermediate and intermediate english students with emphasis on the speking ability.
Falcon stands out as a top-tier P2P Invoice Discounting platform in India, bridging esteemed blue-chip companies and eager investors. Our goal is to transform the investment landscape in India by establishing a comprehensive destination for borrowers and investors with diverse profiles and needs, all while minimizing risk. What sets Falcon apart is the elimination of intermediaries such as commercial banks and depository institutions, allowing investors to enjoy higher yields.
The world of search engine optimization (SEO) is buzzing with discussions after Google confirmed that around 2,500 leaked internal documents related to its Search feature are indeed authentic. The revelation has sparked significant concerns within the SEO community. The leaked documents were initially reported by SEO experts Rand Fishkin and Mike King, igniting widespread analysis and discourse. For More Info:- https://news.arihantwebtech.com/search-disrupted-googles-leaked-documents-rock-the-seo-world/
Memorandum Of Association Constitution of Company.pptseri bangash
www.seribangash.com
A Memorandum of Association (MOA) is a legal document that outlines the fundamental principles and objectives upon which a company operates. It serves as the company's charter or constitution and defines the scope of its activities. Here's a detailed note on the MOA:
Contents of Memorandum of Association:
Name Clause: This clause states the name of the company, which should end with words like "Limited" or "Ltd." for a public limited company and "Private Limited" or "Pvt. Ltd." for a private limited company.
https://seribangash.com/article-of-association-is-legal-doc-of-company/
Registered Office Clause: It specifies the location where the company's registered office is situated. This office is where all official communications and notices are sent.
Objective Clause: This clause delineates the main objectives for which the company is formed. It's important to define these objectives clearly, as the company cannot undertake activities beyond those mentioned in this clause.
www.seribangash.com
Liability Clause: It outlines the extent of liability of the company's members. In the case of companies limited by shares, the liability of members is limited to the amount unpaid on their shares. For companies limited by guarantee, members' liability is limited to the amount they undertake to contribute if the company is wound up.
https://seribangash.com/promotors-is-person-conceived-formation-company/
Capital Clause: This clause specifies the authorized capital of the company, i.e., the maximum amount of share capital the company is authorized to issue. It also mentions the division of this capital into shares and their respective nominal value.
Association Clause: It simply states that the subscribers wish to form a company and agree to become members of it, in accordance with the terms of the MOA.
Importance of Memorandum of Association:
Legal Requirement: The MOA is a legal requirement for the formation of a company. It must be filed with the Registrar of Companies during the incorporation process.
Constitutional Document: It serves as the company's constitutional document, defining its scope, powers, and limitations.
Protection of Members: It protects the interests of the company's members by clearly defining the objectives and limiting their liability.
External Communication: It provides clarity to external parties, such as investors, creditors, and regulatory authorities, regarding the company's objectives and powers.
https://seribangash.com/difference-public-and-private-company-law/
Binding Authority: The company and its members are bound by the provisions of the MOA. Any action taken beyond its scope may be considered ultra vires (beyond the powers) of the company and therefore void.
Amendment of MOA:
While the MOA lays down the company's fundamental principles, it is not entirely immutable. It can be amended, but only under specific circumstances and in compliance with legal procedures. Amendments typically require shareholder
Enterprise Excellence is Inclusive Excellence.pdfKaiNexus
Enterprise excellence and inclusive excellence are closely linked, and real-world challenges have shown that both are essential to the success of any organization. To achieve enterprise excellence, organizations must focus on improving their operations and processes while creating an inclusive environment that engages everyone. In this interactive session, the facilitator will highlight commonly established business practices and how they limit our ability to engage everyone every day. More importantly, though, participants will likely gain increased awareness of what we can do differently to maximize enterprise excellence through deliberate inclusion.
What is Enterprise Excellence?
Enterprise Excellence is a holistic approach that's aimed at achieving world-class performance across all aspects of the organization.
What might I learn?
A way to engage all in creating Inclusive Excellence. Lessons from the US military and their parallels to the story of Harry Potter. How belt systems and CI teams can destroy inclusive practices. How leadership language invites people to the party. There are three things leaders can do to engage everyone every day: maximizing psychological safety to create environments where folks learn, contribute, and challenge the status quo.
Who might benefit? Anyone and everyone leading folks from the shop floor to top floor.
Dr. William Harvey is a seasoned Operations Leader with extensive experience in chemical processing, manufacturing, and operations management. At Michelman, he currently oversees multiple sites, leading teams in strategic planning and coaching/practicing continuous improvement. William is set to start his eighth year of teaching at the University of Cincinnati where he teaches marketing, finance, and management. William holds various certifications in change management, quality, leadership, operational excellence, team building, and DiSC, among others.
What is the TDS Return Filing Due Date for FY 2024-25.pdfseoforlegalpillers
It is crucial for the taxpayers to understand about the TDS Return Filing Due Date, so that they can fulfill your TDS obligations efficiently. Taxpayers can avoid penalties by sticking to the deadlines and by accurate filing of TDS. Timely filing of TDS will make sure about the availability of tax credits. You can also seek the professional guidance of experts like Legal Pillers for timely filing of the TDS Return.
Digital Transformation and IT Strategy Toolkit and TemplatesAurelien Domont, MBA
This Digital Transformation and IT Strategy Toolkit was created by ex-McKinsey, Deloitte and BCG Management Consultants, after more than 5,000 hours of work. It is considered the world's best & most comprehensive Digital Transformation and IT Strategy Toolkit. It includes all the Frameworks, Best Practices & Templates required to successfully undertake the Digital Transformation of your organization and define a robust IT Strategy.
Editable Toolkit to help you reuse our content: 700 Powerpoint slides | 35 Excel sheets | 84 minutes of Video training
This PowerPoint presentation is only a small preview of our Toolkits. For more details, visit www.domontconsulting.com
Exploring Patterns of Connection with Social Dreaming
Apr7.pdf
1. https://nptel.ac.in/content/storage2/courses/106105080/pdf/M5L9.pdf
(http://www.tgpcet.com/ECE-NOTES/8/MOBILE%20COMMUNICATION.pdf)
MULTIPLE ACCESS TECHNIQUES
Multiple access techniques are used to allow a large number of mobile users to share the
allocated spectrum in the most efficient manner.
As the spectrum is limited, so the sharing is required to increase the capacity of cell or
over a geographical area by allowing the available bandwidth to be used at the same
time by different users.
And this must be done in a way such that the quality of service doesn’t degrade within
the existing users.
MULTIPLE ACCESS TECHNIQUES FOR WIRELESS
COMMUNICATION
In wireless communication systems it is often desirable to allow the subscriber to send
simultaneously information to the base station while receiving information from the
base station.
A cellular system divides any given area into cells where a mobile unit in each cell
communicates with a base station.
The main aim in the cellular system design is to be able to increase the capacity of the
channel i.e. to handle as many calls as possible in a given bandwidth with a sufficient
level of quality of service.
There are several different ways to allow access to the channel. These includes mainly
the following:
1. Frequency division multiple-access (FDMA)
2. Time division multiple-access (TDMA)
3. Code division multiple-access (CDMA)
1) FREQUENCY DIVISION MULTIPLE ACCESS
Figure : The basic concept of FDMA.
2. This was the initial multiple-access technique for cellular systems in which each
individual user is assigned a pair of frequencies while making or receiving a call as
shown in Figure.
One frequency is used for downlink and one pair for uplink. This is called frequency
division duplexing (FDD).
That allocated frequency pair is not used in the same cell or adjacent cells during the
call so as to reduce the co channel interference.
Even though the user may not be talking, the spectrum cannot be reassigned as long as
a call is in place.
Different users can use the same frequency in the same cell except that they must
transmit at different times. The features of FDMA are as follows:
The FDMA channel carries only one phone circuit at a time. If an FDMA channel is
not in use, then it sits idle and it cannot be used by other users to increase share capacity.
After the assignment of the voice channel the BS and the MS transmit simultaneously
and continuously.
The bandwidths of FDMA systems are generally narrow i.e. FDMA is usually
implemented in a narrow band system The symbol time is large compared to the
average delay spread.
The complexity of the FDMA mobile systems is lower than that of TDMA mobile
systems. FDMA requires tight filtering to minimize the adjacent channel interference.
FDMA/FDD in AMPS
The first U.S. analog cellular system, AMPS (Advanced Mobile Phone System) is based
on FDMA/FDD.
A single user occupies a single channel while the call is in progress, and the single
channel is actually two simplex channels which are frequency duplexed with a 45 MHz
split.
When a call is completed or when a handoff occurs the channel is vacated so that
another mobile subscriber may use it.
Multiple or simultaneous users are accommodated in AMPS by giving each user a
unique signal.
Voice signals are sent on the forward channel from the base station to the mobile unit,
and on the reverse channel from the mobile unit to the base station.
In AMPS, analog narrowband frequency modulation (NBFM) is used to modulate the
carrier.
FDMA/TDD in CT2
Using FDMA, CT2 system splits the available bandwidth into radio channels in the
assigned frequency domain.
In the initial call setup, the handset scans the available channels and locks on to an
unoccupied channel for the duration of the call.
Using TDD(Time Division Duplexing ), the call is split into time blocks that alternate
between transmitting and receiving.
3. FDMA and Near-Far Problem
The near-far problem is one of detecting or filtering out a weaker signal amongst
stronger signals.
The near-far problem is particularly difficult in CDMA systems where transmitters
share transmission frequencies and transmission time.
In contrast, FDMA and TDMA systems are less vulnerable. FDMA systems offer
different kinds of solutions to near-far challenge.
Here, the worst case to consider is recovery of a weak signal in a frequency slot next to
strong signal.
Since both signals are present simultaneously as a composite at the input of a gain stage,
the gain is set according to the level of the stronger signal; the weak signal could be lost
in the noise floor. Even if subsequent stages have a low enough noise floor to provide
2) TIME DIVISION MULTIPLE ACCESS
In digital systems, continuous transmission is not required because users do not use the
allotted bandwidth all the time.
In such cases, TDMA is a complimentary access technique to FDMA. Global Systems
for Mobile communications (GSM) uses the TDMA technique.
In TDMA, the entire bandwidth is available to the user but only for a finite period of
time. In most cases the available bandwidth is divided into fewer channels compared to
FDMA.
The users are allotted time slots during which they have the entire channel bandwidth
at their disposal, as shown in Figure
Figure : The basic concept of TDMA.
4. TDMA requires careful time synchronization since users share the bandwidth in the
frequency domain. The number of channels are less, inter channel interference is almost
negligible.
TDMA uses different time slots for transmission and reception. This type of duplexing
is referred to as Time division duplexing (TDD).
The features of TDMA includes the following:
a. TDMA shares a single carrier frequency with several users where each users makes
use of non overlapping time slots.
b. The number of time slots per frame depends on several factors such as modulation
technique, available bandwidth etc.
c. Data transmission in TDMA is not continuous but occurs in bursts. This results in
low battery consumption since the subscriber transmitter can be turned OFF when
not in use. Because of a discontinuous trans- mission in TDMA the handoff process
is much simpler for a subscriber unit, since it is able to listen to other base stations
during idle time slots.
d. TDMA uses different time slots for transmission and reception thus duplexers are
not required.
TDMA has an advantage that is possible to allocate different numbers of time slots per
frame to different users.
Thus bandwidth can be supplied on demand to different users by concatenating or
reassigning time slot based on priority.
TDMA/FDD in GSM
GSM is widely used in Europe and other parts of the world. GSM uses a variation of
TDMA along with FDD.
GSM digitizes and compresses data, then sends it down a channel with two other
streams of user data, each in its
3) CODE DIVISION MULTIPLE ACCESS
In CDMA, the same bandwidth is occupied by all the users, however they are all
assigned separate codes, which differentiates them from each other shown in Figure
CDMA utilize a spread spectrum technique in which a spreading signal (which is
uncorrelated to the signal and has a large bandwidth) is used to spread the narrow band
message signal.
Direct Sequence Spread Spectrum (DS-SS)
This is the most commonly used technology for CDMA. In DS-SS, the message signal is
multiplied by a Pseudo Random Noise Code.
Each user is given his own codeword which is orthogonal to the codes of other
users and in order to detect the user, the receiver must know the codeword used
by the transmitter.
5. There are, however, two problems in such systems which are discussed in the
sequel.
Figure : The basic concept of CDMA.
CDMA and Self-interference Problem
In CDMA, self-interference arises from the presence of delayed replicas of signal due
to multipath.
The delays cause the spreading sequences of the different users to lose their
orthogonality, as by design they are orthogonal only at zero phase offset.
Hence in despreading a given user’s waveform, nonzero contributions to that user’s
signal arise from the transmissions of the other users in the network.
This is distinct from both TDMA and FDMA, wherein for reasonable time or frequency
guardbands, respectively, orthogonality of the received signals can be preserved.
CDMA and Near-Far Problem
The near-far problem is a serious one in CDMA. This problem arises from the fact that
signals closer to the receiver of interest are received with smaller attenuation than are
signals located further away.
Therefore the strong signal from the nearby transmitter will mask the weak signal from
the remote transmitter.
In TDMA and FDMA, this is not a problem since mutual interference can be filtered.
In CDMA, however, the near-far effect combined with imperfect orthogonality between
codes (e.g. due to different time sifts), leads to substantial interference.
6. Accurate and fast power control appears essential to ensure reliable operation of
multiuser DS-CDMA systems.
Basic idea of these approaches can be explained in simple terms using
the cocktail party theory. In a cocktail party people talk to each other
using one of the following modes:
FDMA: When all the people group in widely separated areas and talk
within each group.
TDMA: When all the people are in the middle of the room, but they take
turn in speaking.
CDMA: When all the people are in the middle of the room, but different
pairs speak in different languages.