5 ways of increasing the Capacity of cellular system?
Electronics Engineering Questions
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3.7. Improving Coverage and Capacity in Cellular Systems
As the demand for wireless service increases, the number of channels assigned to a cell eventually becomes insufficient to support the required number of users. A t this point, cellular design techniques are needed to provide more channels per unit coverage area. Techniques such as cell splitting, sectoring, and coverage zone approaches are used in practice to expand the capacity of cellular systems. Cell splitting allows an orderly growth of the cellular system. Sectoring uses directional antennas to further control the interference and frequency reuse of channels. The zone microcell concept distributes the coverage of a cell and extends the cell boundary to hard-to-reach places. While cell splitting increases the number of base stations in order to increase capacity, sectoring and zone microcells rely on base station antenna placements to improve capacity by
reducing co-channel interference. Cell splitting and zone microcell techniques do not suffer the trunking inefficiencies experienced by sectored cells, and enable t he base station to oversee all handoff chores related to the microcells, thus reducing the computational load at the MSC. These three popular capacity improvement techniques will be explained in detail.
3.7.1. Cell Splitting
Cell splitting is the process of subdividing a congested cell into smaller cells, each with its own base station and a corresponding reduction in antenna height and transmitter power. Cell splitting increases the capacity of a cellular system since it increases the number of times that channels are reused. By defining new cells which have a smaller radius than the original cells and by installing these smaller cells (called microcells) between the existing cells, capacity increases due to the additional number of channels per unit area.
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Increasing Channel Capacity Adding new channels: Typically, when a system is set up in a region, not all of the channels are used, and growth and expansion can be managed in an orderly fashion by adding new channels.
Frequency borrowing: In the simplest ca se, frequencies are taken from adjacent cells by c ongested cells. The frequencies can also be assigned to cells dynamically.
Cell splitting: In practice, the distribution of traffic and topographic features is not uniform, and this presents opportunities of capacity increase. Cells in areas of high usage can be split into smaller cells.
Cell sectoring: With cell sectoring, a cell is divided into a number of wedge-shaped sectors, each with its own set of channels, typically 3 or 6 sectors per cell. Each sector is assigned a separate subset of the cell's channels, and directional antennas at the base station are used to focus on each sector.
Microcells: As cells become smaller, antennas move from the tops of tall buildings or hills, to the tops of small buildings or the sides of large buildings, and finally to lamp posts, where they form microcells. Each decrease in cell size is accompanied by a reduction in the radiated power levels from the base stations and the mobile units. Microcells are useful in c ity streets in congested areas, along highways, and inside large public buildings.
JDK 7 the Java Development Kit 7 is the latest version of JDK. JDK 7 has lot of enhancements and features as listed below:
Swing Advancements : In JDK 7, a number of swing components like JLayer class, nimbus look and feel, heavy and light weight components etc. have been added. Concurrency Efficacies: In JDK 7, an executor interface has been designed to run proficiently a bulky number of jobs by worker threads. JVM Support: In JDK 7, JVM can support languages other than java. Garbage first collector: In JDK 7, a server side garbage collector known as garbage first collector was introduced to enhance real time portability. Networking Enhancements: In JDK 7, URLclassloader, close method has been included; this can enable extraordinary performance network connections. Security: New features like elliptic curve cryptography, certpath algorithm disabling and others have been included in JDK 7 for security purpose. Varargs: In JDK 7, compiler warnings and errors are upgraded by using Varargs. Customer JRE Competences: Rich internet applications are embedded in JDK 7 which enables client feasibility.
What are the components of JDK?
Components of JDK (Java Development Kit) are:
Java Compiler – Java Compiler is used to compile java files. Java Compiler component of JDK (Java Development Kit) is accessed using “javac” command. Java Interpreter – Java Interpreter is used to interpret the java files that are compiled by Java Compiler. Java Interpreter component of JDK (Java Development Kit) is accessed using “java” command. Java Disassembler - Java Disassembler is used to disassemble Java class file. Java Disassembler component of JDK (Java Development Kit) is accessed using “javap” command. Java Header File Generator - Java Header File Generator is used to generate C language header files and source files to implement the native methods. Java Header File Generator component of JDK (Java Development Kit) is acces sed using “javah” command. Java Documentation – Java Documentation is required for easy maintenance of code. Java Documentation component of JDK (Java Development Kit) is accessed using “javadoc” command. Java Debugger – Java Debugger is used to debug the java files. Java Debugger component of JDK (Java Development Kit) is accessed using “jdb” command. Java Applet Viewer – Java Applet Viewer is used to view the Java Applets. Java Applet Viewer component of JDK (Java Development Kit) is accessed using “appletviewer” command.
Graphics
CSE5280 Computer Graphics
Chapter #2 Solutions
2-1 List the operating characteristics for the following display technologies: raster refresh systems, vector refresh systems, plasma panels, and LCD's.
answer: Read Sections 2-1 through sections 2-3 in your textbook. From reading, basically, you need to understand the following concepts in these sections. These include, refresh systems, frame (display) buffer, raster displays, resolution, refresh display files, passive matrix, active matrix, and run-length encoding.
2-4 Consider two raster systems with the resolutions of 640x480, 1280x1024, and 2560x2048. a) What size frame buffer (in butes) is needed for each of these s ystems to store 12 bits/pixel? How much storage is required for each system if 24 bits per pixel are to be stored?
Frame-buffer size for each of the systems is 640 × 480 × 12 bits ÷ 8 bits per byte = 450 KB 1280 × 1024 × 12 bits ÷ 8 bits per byte = 1920 KB 2560 × 2048 × 12 bits ÷ 8 bits per byte = 7680 KB For 24 bits of storage per pixel, each of the above values is doubled.
2-5 Suppose an RGB raster system is to be designed using an 8 inch x 10 inch screen with a resolution of 100 pixels per inch n each direction. If we want to store 6 bits/pixel in the frame buffer, how much storage (in bytes) do we need for the frame buffer?
Storage needed for the frame buffer is (8 inch x 100 pixels/inch) × (10 inch x 100 pixels/inch) × 6 bits ÷ 8 bits per byte ≈ 486 KB
2-7 Suppose we have a computer with 32 bits/word and a transfer rate of 1 mill ion instructions/second (MIP). How long would it take to fill the frame buffer of a 300 dpi laser printer with a page size of 8.5 inches x 11 inches?
Total bits in the printer frame buffer is 8.5 × 11 × 300**2 ≈ 8.4 × 10**6 bits Therefore, loading time is (8.4 × 10**6 bits) / (32 × 10**6 bps) ≈ 0.263 sec
2-10 How much time is spent scanning across each row of pixels during screen refresh on a raster system with a resolution of 1280 x 1024 and a refresh rate of 60 f rames/second?
The scan rate for each pixel row is 60 frames/sec × 1024 lines/frame = 61, 440 lines/sec And the scan time is approximately 16.3 microseconds per scan line. (Scan time per frame is 1/60 sec, or approximately 16.7 milliseconds.)
2-19 Explain the differences between the OpenGL core librar y, the OpenGL Utility, and the OpenGL Utility Toolkit?
The OpenGL core library contains hardware-independent functions, such as those for specifying primitives, attributes, geometric transformations, and three-dimensional viewing parameters. The GLU library contains functions for some other, more specialized operations, such as quadric-surface generation, B-spline surface generation, surface texture mapping, two-dimensional viewing, and some three-dimensional viewing operations. The GLUT library primarily provides hardware-dependent functions, such as those for display-window management and for interacting with input devices, but it also contains functions for generating various plane-surface, quadric-surface, and cubic-surface solids, such as a cube, sphere, cone, or teapot.
2-21 List the statements needed to set up an OpenGL display window whose lower-right corner is at pixel position (200, 200) with a window width of 100 pixels and a height of 75 pixels?
The GL Utility graphics calls include:
glutInitWindowPosition (100, 125); glutInitWindowSize (100, 75);
Description
Write a java application that will draw the largest possible rectangle in a canvas container. Define a frame containing the drawable canvas container with the size of 200 W X 100 H pixels. Use the color red to distinguish the rectangle from the frame border. In the center of the canvas draw the width and height values of the rectangle drawn.
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