... 18, NO. 3, MARCH 2000 535 Performance Analysis of the IEEE 802.11 Distributed Coordination Function Giuseppe Bianchi Abstract—Recently, the IEEE has standardized the 802.11 protocol for Wireless Local Area Networks. The primary medium access control (MAC) technique of 802.11 is called distributed coordination function (DCF). DCF is a carrier sense multiple access with collision avoidance (CSMA/CA) scheme with binary slotted exponential backoff. This paper provides a simple, but nevertheless extremely accurate, analytical model to compute the 802.11 DCF throughput, in the assumption of finite number of terminals and ideal channel conditions. The proposed analysis applies to both the packet transmission schemes employed by DCF, namely, the basic access and the RTS/CTS access mechanisms. In addition, it also applies to a combination of the two schemes, in which packets longer than a given threshold are transmitted according to the RTS/CTS mechanism. By means of the proposed model, in this paper we provide an extensive throughput performance evaluation of both access mechanisms of the 802.11 protocol. Index Terms—802.11, collision avoidance, CSMA, performance evaluation. I. INTRODUCTION N recent years, much interest has been involved in the design of wireless networks for local area communication [1], [2]. Study group 802.11 was formed under IEEE Project 802 to recommend an international standard for Wireless Local Area Networks (WLAN’s). The final version of the standard...
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...PERFORMANCE ANALYSES OF A MULTI-CARRIER CDMA WIRELESS COMMUNICATION SYSTEM WITH CHANNEL IMPAIRMENT Jobayer Anam Rana ID : 06110024 Nishi Rahman ID:06110021 A Thesis under Supervision of Dr.Satya Prasad Majumder In Partial Fulfillment of the Requirements for the Degree of Bachelor of Science in Electronics and Communication Engineering Department of Electrical and Electronic Engineering (Electronics and Communication Engineering Program) April -2010 BRAC University, Dhaka, Bangladesh i ii DECLARATION We hereby declare that this thesis is based on the results found by ourselves. Materials of work found by other researcher are mentioned by reference. This thesis, neither in whole nor in part, has been previously submitted for any degree. __________ Signature of Supervisor _________ Signature of Author iii ACKNOWLEDGEMENTS By the grace of God we have completed our thesis. We would like to thank our supervisor Dr. Satya Prasad Majumder for giving us the opportunity to work under his supervision. He has always help us by giving suggestions, ideas, advice and support to solve all our problems and guided us to developed this thesis for last two semester. We also thankful to Apurba Saha, Supriyo Shafkat Ahmed, Nazmus Saquib and Rumana Rahman for their inspiration and kind cooperation. We have worked hard and gave our best. Hopefully, our work will appreciated by our supervisor and respected faculties. iv ABSTRACT Analysis of the...
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...MOBILE COMPUTING ASSIGNMENT NAME: SOPHIA EHINOMEN ATIVIE MATRIC NO: 2010/1336 DEPT: INFORMATION TECHNOLOGY 1. CDMA (CODE DIVISION MULTIPLE ACCESS). CDMA (Code-Division Multiple Access) is a channel access method used by various radio communication technologies. It is a form of multiplexing, which allows numerous signals to occupy a single transmission channel, optimizing the use of available bandwidth. The technology is used in ultra-high-frequency (UHF) cellular telephone systems in the 800-MHz and 1.9-GHz bands. CDMA employs analog-to-digital conversion (ADC) in combination with spread spectrum technology. Audio input is first digitized into binary elements. The frequency of the transmitted signal is then made to vary according to a defined pattern (code), so it can be intercepted only by a receiver whose frequency response is programmed with the same code, so it follows exactly along with the transmitter frequency. There are trillions of possible frequency-sequencing codes, which enhances privacy and makes cloning difficult. The original CDMA standard, also known as CDMA One and still common in cellular telephones in the U.S offers a transmission speed of only up to 14.4 Kbps in its single channel form and up to 115 Kbps in an eight-channel form. CDMA2000 and Wideband CDMA deliver data many times faster. Characteristics of CDMA: 1. Spread spectrum techniques use a transmission bandwidth that is several orders of magnitude greater than the minimum...
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...wireless cellular communication into 30 channels, each of which can carry a voice conversation or, with digital service, carry digital data. FDMA is a basic technology in the analog Advanced Mobile Phone Service (AMPS), the most widely-installed cellular phone system installed in North America. With FDMA, each channel can be assigned to only one user at a time. FDMA is also used in the Total Access Communication System (TACS). The Digital-Advanced Mobile Phone Service (D-AMPS) also uses FDMA but adds time division multiple access (TDMA) to get three channels for each FDMA channel, tripling the number of calls that can be handled on a channel. Frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA) are the three major access techniques used to share the available bandwidth in a wireless communication system. These techniques can be grouped as narrowband and wideband systems, depending upon how the available bandwidth is allocated to the users. The duplexing technique of a multiple access system is usually described along with the particular multiple access scheme, as shown in the examples that follow. Narrowband Systems — the term narrowband is used to relate the bandwidth of a single channel to the expected coherence bandwidth of the channel. In a narrowband multiple access system, the available radio spectrum is divided into a large number of narrowband channels. The channels are usually operated using FDD. To minimize...
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...TOSHIBA WIRELESS COMMUNICATION AND VIRTUAL HEALTHCARE A Vision for Remote Diagnostic Access and Service R 10/18/2011 TM583 Strategic Management of Technology Professor E [Type the abstract of the document here. The abstract is typically a short summary of the contents of the document. Type the abstract of the document here. The abstract is typically a short summary of the contents of the document.] TABLE OF CONTENTS I EXECUTIVE SUMMARY……………………………………………………………………………………….3 II ABSTRACT………………………………………………………………………………………………………….3 III OVERVIEW AND COMPETENCIES…………………………….………………………………………….4 IV DISCUSSION OF CURRENT INDUSTRY DYNAMICS………………………………………………..5 V POTENTIAL SOLUTIONS AND SOURCING…………………………………………………………….8 VI RECOMMENDATIONS FOR EXECUTIVE COMMITTEE……………………………………………9 VII ATTATCHMENT………………………………………………………………………………………….………12 VIII REFERENCES………………………………………………………………………………………………………13 I EXECUTIVE SUMMARY This research paper examines the capabilities of remote diagnostic access (RDA), and a proactive monitoring system as a foundation of medical equipment telemaintenance framework. In addition, this research will show how the cost effectiveness of such a system, can provide consistent monitoring of elaborate time sensitive data and systems without constraints. Due to recent growth and expansion into the medical equipment industry, the centralization of resources can expedite repair services, and this paper will give...
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...Generation (2G) technology was launched in the year 1991 in Finland. It is based on the technology known as global system for mobile communication or in short we can say GSM. This technology enabled various networks to provide services like text messages, picture messages and MMS. In this technology all text messages are digitally encrypted due to which only the intended receiver receives message. These digital signals consume less battery power, so it helps in saving the battery of mobiles. The technologies used in 2G are either TDMA (Time Division Multiple Access) which divides signal into different time slots or CDMA (Code Division Multiple Access) which allocates a special code to each user so as to communicate over a multiplex physical channel. 3G technology generally refers to the standard of accessibility and speed of mobile devices. It was first used in Japan in the year 2001. The standards of the technology were set by the International Telecommunication Union (ITU). This technology enables use of various services like GPS (Global Positioning System), mobile television and video conferencing. It not only enables them to be used worldwide, but also provides with better bandwidth and increased speed. This technology is much more flexible as it can support 5 major radio technologies that operate under CDMA, TDMA and FDMA. CDMA accounts for IMT-DS (direct speed), IMT-MC (multi carrier). TDMA holds for IMT-TC (time code), IMT-SC (single carrier). This technology is also...
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...time frame. Choosing the most effective and profitable distribution channel is a challenging dilemma. The choice to use a direct or indirect distribution channel might feasible be the difference in selling all or only some of the product, and selling at a low or high price. The direction a producer decides to take has many variables including cost of distribution, and available markets. The decision to sell the corn supply using both methods is the most conceivable probability for this product. Introduction The product of fresh corn is a product that has a limited shelf life and distribution time frame. Choosing the most effective and profitable distribution channel is a challenging dilemma. The choice to use a direct or indirect distribution channel might feasible be the difference in selling all or only some of the product, and selling at a low or high price. A distribution channel is the avenue a product takes from producer to consumer. (Board, 2012) This avenue varies in length depending on the producer’s preference. There are two types of distribution channel available to producers, direct and indirect. The direction a producer decides to take has many variables including cost of distribution, and available markets. The decision to sell the corn supply using both methods is the most conceivable probability for this product. Overview of Distribution Channels A direct distribution channel takes the shorts and simplest track from producer to consumer. (Board...
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...http://www.scirp.org/journal/jss http://dx.doi.org/10.4236/jss.2014.24039 The Differentiated Pricing Strategy or Hotel under Dual-Channel Reservation Forms Xiaoyan Xu, Rui Zhao*, Liang Xu School of Management, University of Science and Technology of China, Hefei, China * Email: zhr11@mail.ustc.edu.cn Received 6 March 2014; revised 7 April 2014; accepted 15 April 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract The modern information network environment largely changed consumer habits. Hotel Reservation way becomes increasingly diversified. By building the traditional and Internet booking ways’ demand functions which were linear in self- and cross-price effects and the hotel revenue function, we determine the optimal pricing strategy of the hotel’s Internet booking way. The effect of the optimal strategy is also discussed, and numerical simulation verifies that the optimal strategy can greatly improve the hotel revenue. All of the research propositions help hotel managers make deeper understanding of fixed room quantity’s influence on pricing strategies, and provide managers the basis of pricing strategy. Keywords Differentiated Pricing Strategy; Multi-Channel Reservation; Hotel Revenue Management 1. Introduction The rise of the Internet are profoundly changing the consumer’s lifestyle...
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...essence of today’s technologically advanced world. The two most basic methods of digital communication are: Serial and Parallel. Parallel communication involves multiple wires running parallel to each other and can transmit data on all the wires simultaneously. However, Serial communication requires a single wire for transferring data bits one at a time. A natural question arises out of human curiosity: which one of the two methods is better. This term paper discusses these two methods, their various applications and the advantages of the Serial Communication method over the Parallel one. Index Terms—Parallel Communication, Serial Communication UART, RS-232 DTE, Synchronous, Asynchronous. Parallel counterpart have been resolved. Although the Parallel Transmission Method is still used within internal buses and for devices such as printers, but the latest devices, ports and technologies are mostly based on Serial Techniques. For example - Universal Serial Bus and WAN, both make use of the Serial Type Data Transmission. II. TERMS USED IN DATA COMMUNICATION A. Transmission Distance The transmission distance of a communication signal is the length of path the signal travels as it goes from transmitter to the receiver. B. Data Terminal Equipment (DTE) Data Terminal Equipment (DTE) is a device or equipment that acts either as a source or as destination during the transmission of data signals. A DTE controls the communication channel. However, DTEs don‟t directly communicate with each...
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...customers, the customers better understand the value that is being offered. A major way marketers create positive and distinct images is through marketing communications. 1.3. Identify Prospects Identifying prospects is becoming an increasingly important goal of marketing communication because modern technology makes information gathering, much more practical, even in large consumer markets. Technology now enables marketers to stay very close to their customers. 1.4. Build Channel Relationships When producers use marketing communications to generate awareness, they are also helping the retailers who carry the product. Producers may also arrange with retailers to distribute coupons, set up special displays, or hold promotional events in their stores, all of which benefit retailers and wholesalers. Retailers support manufacturers when they feature brands in their ads to attract buyers. Cooperating in these marketing communication efforts can build stronger channel relationships. 1.5. Retain Customers Loyal customers are a major asset for every business. It costs far more to attract a new customer than to retain an existing customer. Marketing communications can support efforts to create value for existing customers. They can...
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...Communication Channels Paper 1 Communication Channels Paper Communications Channels Paper Jean Nedd Health Care Communication Strategies HCS/320 Communication Channels 2 Communication Communication is the process of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast distances in time and space. Communication requires that the communicating parties share an area of communicative commonality. The communication process is complete once the receiver has understood the message of the sender. Communication can be in many channels, and common written forms include email, text, or fax. Verbal communication channels include forms like talking on the telephone or Skype. Nonverbal communication comes in forms through hand jesters, memo or letters. Every organization needs information, and they use it to communicate with other people or to suggest intent. Every person needs to understand the way that different communication channels are used. In this paper I will use two organizations, Halifax Community Clinic and Greenfield/ Bresler LTD. with different styles to show how each use there written and verbal communication skills in there daily operations. Organizations: Halifax Health Community Clinic Halifax Health Community Clinic uses both...
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...// you're reading... Uncategorized Integrated Marketing Communication Strategy from Principles of Marketing by Philip Kotler & Gary Armstrong Posted by neylinee ⋅ April 23, 2011 ⋅ Leave a Comment Under the concept of integrated marketing communications, a company will carefully coordinate the promotion elements to deliver a clear, consistent, and compelling message about the organization and its products. Mini campaign: “let’s not use the size of our vehicle to make up for other shortcomings” MINI communications campaign has been impressive both for what it does and for what it doesn’t do. Modern marketing calls for more than just developing a good product, pricing it attractively, and making it available to target customers. Companies must also communicate with current and prospective customers, and what they communicate should not be left to chance. All of their communications efforts must be blended into a consistent and coordinated communications program. Just as good communication is important in building and maintaining any kind of relationship, it is a crucial element in a company’s efforts to build profitable customer relationships. The marketing communications mix (Promotion Mix) The specific mix of advertising, personal selling, sales promotion, and public relations a company uses. Advertising any paid form of nonpersonal presentation and promotion of ideas, goods, or services by an identified sponsor. Sales promotion short-term incentives to encourage...
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...COMMUNICATION PROCESS In order to sustain our relationships with other people and to get what we need or want in life, we need to go through the process of communication or, the communication process, which we go through every days of our life but unaware of it. Communication is simply the process whereby people share their feelings, thoughts, experiences and suggestions to each other; to create a shared understanding. It is a process that allows people to exchange their information by one of several methods depending on the message and the context. It is an effective way to show our needs, demands, the information reaches people via various modes, which is through speech, visuals, poems and books, the information can be in the form of words, gestures, drawings, songs/music or paintings. Before communicating to each other, it is important to first generate the ideas in our minds because it is impossible to communicate to each other without having a meaningful idea. The process of communication has no standard definition or explanation; it can be defined according to individual understanding. Communication is the process of sharing our ideas, thoughts, and feelings with other people and having those ideas, thoughts, and feelings understood by the people we are talking with. (www.studymode.com). This simply means that every word that comes out of our mouths trying to convince or tell someone something is taken as a process to communicate to another party. According to Charles...
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...Introduction This task I am going explain the process of distributing goods through different channels from the manufacturer to the customers. The term distribution means the process of delivering, storing and selling goods, so that they can be used by customers. (Source- Intermediate Retail and Distribution, Delivering is about what types of transport which are used to carrying and delivering goods, the types of transport is going to be Rail, Road, Air, Water for example rivers, ocean cargo and canals and People. Storing is about where the goods are going to come from and where they are going to be stored. Selling is going to be where you are going to sell the goods Distribution Channel Distribution channel is the chain of individuals and organisations involved in getting a product or service from the producer to the consumer. Distribution channels are also known as marketing channels or marketing distribution channels in this context, the individuals and organizations are known as intermediaries; channels are categorised according to the number of intermediaries between the producer and the end user. A direct marketing channel, for example, which has no intermediaries between the producer and the consumer, is known as a level zero channels. http://searchitchannel.techtarget.com/definition/distribution-channel Distribution Process Supply Chain A supply chain is the path leading from the raw materials a company uses, through manufacturing, distribution and selling until...
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...turbulent flow and heat transfer was performed in four types of rotating channels. The first type is a rotating rectangular channel with V-shaped ribs. The channel aspect ratio (AR) is 4:1, the rib height-to-hydraulic diameter ratio (e/Dh) is 0.078 and the rib pitch-to-height ratio (P/e) is 10. The rotation number and inlet coolant-to-wall density ratio were varied from 0.0 to 0.28 and from 0.122 to 0.40, respectively, while the Reynolds number was varied from 10,000 to 500,000. Three channel orientations (90 degrees, −135 degrees, and 135 degrees from the rotation direction) were also investigated. The second type is a rotating rectangular channel with staggered arrays of pinfins. The channel aspect ratio (AR) is 4:1, the pin length-to-diameter ratio is 2.0, and the pin spacing-to-diameter ratio is 2.0 in both the stream-wise and span-wise directions. The rotation number and inlet coolant-to-wall density ratio varied from 0.0 to 0.28 and from 0.122 to 0.20, respectively, while the Reynolds number varied from 10,000 to iv 100,000. For the rotating cases, the rectangular channel was oriented at 150 degrees with respect to the plane of rotation. In the rotating two-pass rectangular channel with 45-degree rib turbulators, three channels with different aspect ratios (AR=1:1; AR=1:2; AR=1:4) were investigated. Detailed predictions of mean velocity, mean temperature, and Nusselt number for two Reynolds numbers (Re=10,000 and Re=100,000) were carried out. The rib height...
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