...Computer Applications (0975 – 8887) Volume 8– No.12, October 2010 Handover management in GSM cellular system Jahangir khan School of computer science PAF-KIET, Pakistan Air Force Base korangi Creek Karachi 75190 Pakistan ABSTRACT Handover mechanism is extremely important in cellular network because of the cellular architecture employed to maximize spectrum utilization. Handover is the procedure that transfers an ongoing call from one cell to another as the user’s moves through the coverage area of cellular system. One way to improve the cellular network performance is to use efficient handover prioritization schemes when user is switching between the cells. In this paper I have presented an analytical framework that can enhance considerably the handover call mechanism in wireless network. Some advance schemes namely, guard channels, call admission control and handover queuing are discussed. All these of prioritiztaions schemes have a common characteristic reducing the call dropping probability at the expense of increased call blocking probability. Efficnet prioritiztaion scheme accomadetes a number of new calls while guaranates the quality of sevice(QOS) of hanover call. This idea is based on the neighbouring cells have an ovelapping (the area served by more than one cell) coverage area. Furthermore cell overlap and load balancing scheme is proposed to enhance the GSM cellular capacity using an overlapping coverage area. Capacity enhancement is achieved by balancing the...
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...EC635 Advanced Topics in Communication Systems R. S. Kshetrimayum A.3 Cellular Concepts Topics: A.3.1 Frequency reuse A.3.2 Cluster and Capacity A.3.3 Reuse distance A.3.4 CCI and system capacity A.3.5 SIR Introduction: The design objective of early mobile radio systems was to achieve a large coverage area using a single, high powered transmitter with an antenna mounted on a tall tower The cellular concept is a system-level idea which calls for replacing a single, high power transmitter (large cell) with many low power transmitter (small cells) each providing a coverage to only a small portion of the service area While it might seem natural to choose a circle to represent the coverage of a BS, adjacent circles cannot be overlaid upon a map without leaving gaps or creating overlapping regions Thus when considering geometric shapes which cover an entire region without overlap and with equal area, there are three sensible choices – a square, an equilateral triangle and a hexagon The actual radio coverage of a cell is known as footprint and is determined from field measurements or propagation prediction models (a) (b) (c) Fig. A.3. 1 (a) Theoretical Coverage (b) Ideal Coverage (c) Real Coverage EC635 Advanced Topics in Communication Systems Why hexagon for theoretical coverage? R. S. Kshetrimayum For a given distance between the center of a polygon and its farthest perimeter points, the hexagon has the largest area of the three Thus by using hexagon geometry, the fewest...
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...1. Evaluation of the Changes that Dore Dore has made to its Children’s division The use of cellular manufacturing in the Children’s division would generally bring about greater efficiency for the following reasons. First and foremost, it would save time by reducing transfer time. Given that the production machinery would be clustered together in a cell, transfer of work-in-progress along the production line would be much faster. Second, in a cellular system the workers are generally cross-trained. This allows greater utilization of the human resource at hand and thereby reduces worker idle time significantly. Third, given the cross training of worker, a bottle-neck is less likely to occur or be a problem. Whenever work-in –progress starts accumulating in a particular operation, the cross trained workers would be able to help prevent the creation of a bottle-neck. To surmise, cellular production would be largely beneficial particularly since it would drastically decrease the flow time. However, it has to be recognized that the cellular manufacturing layout would also entail costs. First, there would have to be multiple machinery that would have to be acquired as now machines would not be shared according to the task performed. Acquisition of new machines would certainly be costly. Second, another related disadvantage would be that there would be greater idle time experienced by the machines and consequent inefficient use of the machines. Third, it is also necessary to be cognizant...
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...WorldConnect services all their subscribers can get services in more than 100 countries (Funding Universe, 2011). The origins of AT&T Wireless stems from the merger between AT&T Corp with McCaw Cellular Communications. The development of wireless technology first began with AT&T Corporation, where cellular technology was invented 1947 in the Bell laboratories for law enforcement (Funding Universe, 2011). The main reason these systems were developed for law enforcement was so that patrol cars can stay in contact with each other, because prior to this they communicated through radio frequencies which tend to collapse if too many patrol cars were using it. AT&T engineers solved the solution of the issues with the radio frequency by creating special transmitters capable of sending calls between patrol cars regardless of what area they were located in this was a precursor to the creation of cellular towers in the 20th century (Funding Universe, 2011). The first actual cellular systems were not developed until 1984 by AT&T Corp. in the cities of Chicago and Washington, D.C. Even though AT&T Corps was the first to develop cellular systems other corporate competitors took the lead in introducing it to the masses. AT&T Corp. realized the potential of cellular phone service once they met McCaw Cellular Communications, and as a result both companies merged to form what is currently known as AT&T Wireless. Prior to McCaw merging with AT&T Corp. were in the business of cable television, which...
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...Data on Fixed Line vs. Cellular Debate The debate over the merits of fixed line vs cellular data transmission is complex. There are many issues that define the advantages and disadvantages of both styles of communication. One obvious aspect to be considered is the need for mobility and portability. Not only is there any increasing demand in business communications, but the personal market in mobile information technology is experiencing explosive growth. With this growth come several concerns. Some of these include: 1. Security attacks when using unsecured connections. 2. Unwanted device connection (such as neighboring Bluetooth devices) 3. Reliable connections (building construction, distance to tower, etc.) 4. Lost or stolen devices. 5. Loss of service due to discharged batteries. Many advantages also exist with mobile cellular connections such as cheaper calling rates (especially on long distance calls), can double as mobile access point for laptops, and access where fixed line connections are not available. Also, cellular connections are safer during electrical storms as a direct connection to physical lines is not needed. Fixed line connections have some advantages over cellular. One advantage is the ability to make large downloads faster (although this is becoming less and less of a limiting factor with cellular connections). Currently, fixed line connections are cheaper that cellular for data transfer. Another advantage is in security. Fixed line connections...
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...56 Define the following terms: Cellular respiration (aerobic respiration) (2 points) Cellular respiration is the process by which cells get their energy in the form of ATP. There are two types of cellular respiration, aerobic and anaerobic. Aerobic respiration is more efficient and can be used in the presence of oxygen. Aerobic respiration, or cell respiration using oxygen, uses the end product of glycolysis in the TCA cycle to produce more energy currency in the form of ATP than can be obtained from an anaerobic pathway. Fermentation (anaerobic respiration) (2 points) Fermentation is a metabolic process converting sugar to acids, gases or alcohol. It occurs in yeast and bacteria, but also in oxygen-starved human muscle cells. Fermentation is used by humans to make beer and food, like kimchi. Fermentation is a form of anaerobic digestion that generates ATP by the process of substrate-level phosphorylation. Summarize what occurs during the three steps of cellular respiration and indicate where each process takes place in the cell. (6 points) Glycolysis: It is a process that occurs in the cytoplasm. It converts each molecule of glucose to two molecules of pyruvic acid. It refers to an anaerobic process that proceeds whether or not oxygen is present or not. The pyruvic acid diffuses into the inner compartment of the mitochondrion where a transition reaction occurs that starts to prepare pyruvic acid for the next stage of respiration. Krebs cycle-This is...
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...landline system: • Greater reliability of service; since calls are coming and going over physical lines, calls are clearer and more stable. • Ease of Maintenance: corded phones are easy and relatively inexpensive to repair over the complicated cell phone/smartphone. • Greater Security: much more difficult to listen or break in on landlines over radio waves. • Data speed of landline: 256kbps (Landline DSL) • Speeds are dependent on the ISP. Advantages of a Cellular system: • Portability: able to work from (almost) anywhere • Not as easy to repair/more expensive as well • Less secure: radio waves are easier to intercept than landlines • Current data speeds for cellular data: 4G can deliver download peak speeds of 100Mbs and upload speeds of 50Mbs. 3G currently provides data transfer speeds of up to 384kbps. EDGE currently provides data transfer speeds of up to 170kbps. GPRS currently provides data transfer speeds of up to 56kbps. So depending on where you are located this can be very good or not so much. • Cell phones offer GPS data for tracking • You would need less equipment: with the landline system you would need phones, computers, routers and all the wires. With cellular you would need a phone and maybe a tablet or laptop. Much less expensive in start-up. In my opinion, when considering all the progress made in cellular technology in the past few years it is still prudent to conduct a business that relies on a constant, stable network a landline system is still...
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...prospects of mobile computing in Nigeria. The paper will be analyzed by theme in order to provide a thematic overview as well as a comparative analysis of the development role of mobile computing. In exploring the evidence from completed projects as well as the foci of new projects, the paper summarizes and critically assesses the key findings and suggests possible avenues for future research. CHAPTER ONE INTRODUCTION The fusion of computer and telecommunication technologies has heralded the age of information superhighway over wire-line and wireless networks. Mobile cellular communication systems and wireless networking technologies are growing at an ever-faster rate, and this is likely to continue in the foreseeable future. Wireless technology is presently being used to link portable computer equipment to corporate distributed computing and other sources of necessary information. Wide-area cellular systems and wireless LANs promise to make integrated networks a reality and provide fully distributed and ubiquitous mobile communications, thus bringing an end to the tyranny of geography. Higher reliability, better coverage and services, higher capacity, mobility management, power and complexity for channel acquisition, handover decisions, security management, and wireless multimedia are all parts of the potpourri. Further increases in network security are necessary before the promise of mobile telecommunication can be fulfilled. Safety and security management against fraud...
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...pre operating system. Peterson has to report, Chip Knight the director of pre operating system in two weeks. Peterson is looking forward to talk with knight about his plan for dealing with problems which he is facing. About Erik Peterson: Erik Peterson was native of Minnesota. He was 31 year old, he attended business school. He did BS in electrical engineering from MIT and master’s degree from Dartmouth’s Thayer School of engineering. He had worked as designer engineer at avionics equipment. Moreover he had been an Officer in the US Army Signal Corps. He interviewed companies in industry as part of his second year job search, and interviewed by Ric Jenkins, its president and founder. He had no previous worked experience in cellular industry. Cellucomm Organization was a challenge for Peterson he felt very fortunate to have opportunity to work directly under Jenkins. Background: Erik Peterson was hired as general manager at Green mountain Cellular, (GMCT) one of Cellucomm ‘s subsidiaries. It is a “pre operating “system and still in construction phase. GMCT will serve 400,000 people and operate 21 cell sites, 16 sites were anticipated to be ready by turn on date and five other in eight month following GMCT is one month behind the target because of numerous problem, the revised turn on date is April 1st and Peterson is schedule to meet Knight in two weeks to discuss various problem that have led to delay. Cellular Telephone Industry Overview: The cellular mobile telephone...
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... Through Cellular phones to save Accident Victims -Boon for the cellular phone users * * Abstract: This paper describes an ORIGINAL IDEA to help cellular phone users caught in an accident. The idea has been developed keeping in mind the considerations of cost and compatibility with existing system. The Short Message Service or SMS as it is popularly referred to, is made use of for this purpose. The solution offered is the Force-Transducer method. The victim is assumed to be unconscious and the accident is detected automatically. Detailed simulation results at a scaled down level are provided for this solution. The threshold level is set based on data collected from the experiments. One major problem in such design is the technique to find the victim’s position. The Global Positioning System (GPS) is found to be costly. So, an unorthodox design using Radio Direction Finders (RDF) and beacon signals is described. The Goniometer or Crossed Loop Antenna is used for this purpose. This reduces cost effectively when compared with the GPS system. The paper proceeds to suggest an abstract view of the software robot required to perform the Save Our Souls (SOS) message routing task. It uses a special hierarchical message dispatch system wherein people nearby...
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...Mobile Databases Roosevelt Smith, Jr. DBM 384 November 12, 2012 Jim Cervi Mobile Databases Databases provide individuals and organizations the means to track various types of information. According to Stephens (2009), “A database is a tool that accumulates information, and lets one produce, read, revise, and remove the data in some manner.” (p. 23) A mobile databases is a databases that can be connected with by a linking with a laptop device over a mobile system. A mobile database provides a portable and physically separate system form the main system; however, it is still able to link to the main system through remote sites for various file sharing of company data. Mobile Database Platforms The incorporation of mobile databases in use throughout society today, provides the integration of various platforms devices. Some of the mobile database platforms devices include laptops, personal data assistants or (PDA’s), and cellular phones. In addition to the mobile platform devices, on must also consider the various server support for the client platforms that include: * Java * Android * Blackberry * Windows Desktop & Mobile * Linux Many programs and applications like databases require the need or capability to acquire data from an intelligence depository and conduct operations on this data even after out of area. SQL Support Sybase Inc.’s SQL Anywhere controls the mobile-database arena, surrounding 68 percent of the mobile marketplace...
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...Associate Program Material Cell Energy Worksheet Answer the following questions: Cellular respiration: • What is cellular respiration and what are its three stages? Cellular respiration is the aerobic harvesting of a chemical energy from organic fuel. The three stages are glycolysis, citric acid cycle, and electron transport. • What is the role of glycolysis? Include the reactants and the products. Where does it occur? The role of glycolysis is splitting sugar into two parts. This allows the cells to make ATP. When the splitting of the two molecules of ATP happen they turn into two molecules of pyruvic acid and the two electrons carrying NADH are produce. • What is the role of the citric acid cycle? Include the reactants and the products. Where does it occur? The role of the citric acid cycle is to reduce and carry electrons that are high in energy to the next stage. In this stage, glycolysis is converted to acetyl CoA by creating many compounds that can store the high-energy electrons along the ATP molecules. • What is the role of the electron transport system? Include the reactants and the products. Where does it occur? The electron transport system transfers the electrons through electron carriers. The energy that is released by electrons pumps hydrogen ions across the inner membranes of the mitchondrin, thus creating high hydrogen ion concentration. ...
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...We had the days when the telephones only served the purpose of communication through sound. Mobile phone has completely changed the concept of the telephoning. Now a phone is not only a mere phone but it is a lot in itself. A mobile phone works on a unique networked system which needs no wiring, no fixation and no botheration. Originally it was used in cars, airlines, and passanger trains but increasingly it is becoming ubiquitous. It is basically low- power radio telephone. In this magical system calls go through radio transmitters that are located within small geographical unit which are known as cells. Since each cell's signals are too weak to interfere with those of other cells operating on the same frequencies and more channels can be used than would be possible with high power radio frequency transmission. Narrow-band frequency modulation (FM) is the most common mode of transmission, each message is assigned a carrier, unique to the cell from which it is transmitted. The cellular phone was first tested in 1978. The cellular market in Britain alone had grown at a rapid rate to 8.5 million users by 1997. In Japan it is as high as one mobile phone per ten people. However, when the number of cellulars users had increased many new subscribers are low users. In the United Kingdom cable operators are giving some five lakh extra subscribers per month. Presently China tops the list of the mobile user...
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...Cell phones How have they changed us socially? A mobile phone (also known as a cellular phone, cell phone, and a hand phone) is a device that can make and receive telephone calls over a radio link while moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network. By contrast, a cordless telephone is used only within the short range of a single, private base station. In addition to telephony, modern mobile phones also support a wide variety of other services such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and photography. Mobile phones that offer these and more general computing capabilities are referred to as smartphones. The first hand-held mobile phone was demonstrated by John F. Mitchell[1][2] and Dr Martin Cooper of Motorola in 1973, using a handset weighing around 2.2 pounds (1 kg).[3] In 1983, the DynaTAC 8000x was the first to be commercially available. From 1990 to 2011, worldwide mobile phone subscriptions grew from 12.4 million to over 6 billion, penetrating about 87% of the global population and reaching the bottom of the economic pyramid.[4][5][6][7] Before the devices that are now referred to as mobile phones existed, there were some precursors. The development of mobile telephony began in 1918 with tests of wireless telephony on military trains between Berlin...
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...Cellular Debate Name Course Date Tutor Network Security Issues on Cellular Network One major advantage of Cellular network security is the ability of communication to be done “Wirelessly” (Xiao et al, 2007). This means that the signals do not follow a specific assigned signal path which may be destroyed by vandals or even by nature, as in case of copper conductors or other physical media such as fiber optic. In addition, data security is enhanced by used of packed switched data in which data is send in form of packets and at no particular order only to be reconstructed at the receiver which makes intercepting such messages cumbersome. In addition, user authentication allows only specific users registered to a specific cellular service provider to use their resources thus allow proper billing to be charged according to the usage of the network(Xiao et al, 2007). A security issue that arises from the use of the cellular networks is subscriber authentication. These systems consist of a large number of subscribers who need to be identified and verified before they can enjoy the services offered by the provider. If authentication is not properly done, then the network is vulnerable to misuse by subscribers not entitled to use the network leading to the service provider incurring losses. Confidentiality is another security issue that can be noted in cellular network (Ciampa, 2009). This is because the ‘air’ channel can be intercepted by malicious people and...
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