Dcf Distributed Coordination Function Computer Science Essay

Dcf Distributed Coordination Function Computer Science Essay Fragmentation It is the process used in MAC IEEE 8021.11 to break ­ing apart a packet into smaller pieces. Fragmentation is process that dividing long frame to several shorter frame. Using this technology because the Wireless LANs have high bit error rates. The probability of losing frame is much higher for wireless links. The 802.11 uses fragmentation to reduce the frame error rate. The PCF is supporting sensitivity traffic and support some high priority application. Therefore the real time application data need to transmitted without any delay. The probability of lost frame is much higher for wireless links. Thats why fragmentation is used to Reduces amount of time medium is in use and Reduces probability of collisions. And there some pervious work has been done which related to our title, will be shown in next sections. Acknowledgment: Acknowledgments the patience and support of my family was the biggest help in the completion of this project. And would also like to acknowledge for my supervisor Mr.Manssor Ali and for module tutor Prof. Vallavarj, and module leader Mr. Vijay Krishna, for their guiding. Also, I would like to thank the project coordinator Ms. Pravenna , for encouraging me to complete this work and my study. Nomenclature MAC: Medium Access Control. DCF: Distributed Coordination Function. PCF: Point Coordination Function. AP: Access Point. BSS: Basic Service Set. IBSS: Independent Basic Service Set. ESS: Extend Service Set. RTS: Request To Send. CTS: Clear To Send. ACK: Acknowledgement. OSI: Open System Interconnection. LLC: Logical Link Control. HTTP: Hyper Text Transfer Protocol NAV: Network Allocation Vector. DSSS: Direct Sequence Spread Spectrum. Contents Page Contentsà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦.. Page No Abstractà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦.à ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦. i Acknowledgementà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦ii Nomenclatureà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦..iii Contents pageà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦..iv List of figuresà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦v Chapter 1: Introductionà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦7 1.1) General Informationà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦..7 1.2) Aim Of the projectà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦7 1.3) Project Objectiveà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦..8 1.4) Honors challengesà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦.8 Chapter 2: literature Review..9 Backgroundà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦..9 IEEE MAC 802.11physical layerà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦10 what is Fragmentation.10 Why we are using this Technology.12 The advantages and disadvantages of fragmentation..12 Distributed Coordination function (DCF)13 Fragmentation Operation.14 Point Coordination function (PCF)à ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦..15 Analysis The earliest work in data fragmentation IEEE802.1116 Chapter 3 Literature Review analysis..19 solutions for all above problems.19 Future Work..20 Chapter 4 Research Problem.21 Chapter 5 Design and Experiment Setupà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦..22 Chapter 6 Conclusionà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦.23 Chapter 7 Referencesà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦.25 List of figures Figure name Page No. Figure (1) Independent Basic Service Set(IBSS)à ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦ 11 Figure (2) Infrastructure Basic Service Set à ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦ 11 Figure (3) Fragmentation The RTS/CTS access methodà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦. 13 Figure( 4) MSDU divided into several MPDUà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦ 14 Figure (5). Combination DCF PCF. 15 Figure (6) The effect of (polling overhead )on network throughput17 Figure (7),Effect of fragmentation. 18 Figure (8), WLAN Setup diagram in OPNETà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦.. 22 Chapter 1 Introduction 1.1) Aim: Study on the effect data fragmentation on the performance of IEEE 802.11 wireless LAN under PCF mode.fragmentation used to increase reliability transmit frame by divide 802.11 frames into smaller pieces (fragments) that are sent separately to the destination. 1.2) The objectives in this paper will be as follows: 1)The first objective in this paper will be understand the Theory and different standards of IEEE 802.11. 2)To understand the what are structure of the wireless network 3)To evaluate and analyse the effect data fragmentation on the performance of IEEE 802.11 wireless LAN under PCF mode. )Selection for suitable simulation tool4 5)To design suitable WALN with appropriate settings 6)Study the critical evaluation of the result. 1.3) Honours challenge: Critical analysis and evaluation of the results. Experimental Investigation of existing work. 1.4) General Information: The motivation i select this project title , is because in my organization they are looking for wireless network technology ,which can provide such applications like for delivering traffic for real-time applications such as Voice and data . Therefore IEEE 802.11 under point coordinate function PCF can satisfy the requirement, we will see that later. wireless local area network (WLAN), make people on the move to communicate with anyone and anywhere at anytime Caledonian college is one best example which is providing wireless service inside the college camps which allows the student to share data and web brows. The IEEE 802.11 WLAN has two different type of method channel accessing ,the distributed coordination function (DCF) and point coordination function (PCF). DCF is based on the carrier sense multiple access with collision avoidance (CSMA/CA) mechanism, while PCF is based on using the polling technique. The DCF mode of operation consists of two techniques for packet transmission. In the default its operate as a two-way handshaking technique where a positive acknowledgment is transmitted by the receiver station. (Stallings, 2007) . Fragmentation It is the process of break ­ing apart a packet into smaller pieces. A source (wireless Network Interface Card or access point) uses for fragmentation is to divide 802.11 frames into smaller pieces (fragments) that are sent separately to the destination. The fragments are all marked in a way that allows the destination device to put them back together again after it gets all the fragments. 1.5)The some of earliest work in data fragmentation IEEE802.11: Dynamic Fragmentation Scheme fro Rate -Adaptive WLAN.[7] Improving the Aggregate Throughput of Access Points in IEEE802.11Wireless LANs[26]. Performance Analysis of Packetized Voice Transmission with PCF in IEEE802.11Wirelessnetwork.[27] Delay Analysis of IEEE 802.11 PCF MAC based Wireless vetworks.[28] Performance Evaluation of the IEEE 802.11 Wireless LAN Standards [6]. Performance Enhancement of Wireless Local Networks. [20] Chapter 2 Literature Review Before we will go in depth of our title on data fragmentation under PCF mode , we must understand The basic building block of the WLAN network in IEEE 802.11., And our first objective will be covered in this section. 2.1) Background: In this section we will be discussing about wireless local area network (WLAN), which make people on the move to communicate with anyone and anywhere at anytime Caledonian college is one best example which is providing wireless service inside the college camps which allows the student to share data and web brows ,but increasing demand on portable computer for example Laptops and increasing communication equipment, its has responsibility of increasing in wireless network service. As we know this technology is working under protocols to control the service between users. Each type of wireless data network operates on a specific set of radio frequencies. For example, most Wi-Fi networks operate in a special band of radio frequencies around 2.4 GHz that have been reserved in most parts of the world for unlicensed point-to-point spread spectrum radio services. Other Wi-Fi systems use a different unlicensed band around 5 GHz. (Ross , 2008) ) IEEE MAC 802.11physical layer are defined in three type:2.2 Direct sequence spread spectrum (DSSS):its operating in the 2.4 GHz band at data rate of 1Mbps and 2Mbps, the number of channels available depend on the bandwidth. Frequency hopping spread spectrum(FHSS): operating in 2.4GHz at data rates of 1Mbps and 2Mbps, the available channel range is 23 in japan,70in USA. Infrared : data rate is 1Mbps and 2Mbps operating at a wavelength between 850and 950 nm. For IEEE 802.11 there are different standards as we can see ,but my study will be based on IEEE 802.11:[4] à ¢Ã¢â€š ¬Ã‚ ¢ IEEE 802.11: Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) Medium Access Control (MAC), and 1 and 2 Mbps for DSSS, FHSS in 2.4 GHz band, and Infrared, ratified in 1997. à ¢Ã¢â€š ¬Ã‚ ¢ IEEE 802.11a: Works at 6, 9, 12, 18, 24, 36, 48 and 54 Mbps in 5GHz band, ratified in 1999. à ¢Ã¢â€š ¬Ã‚ ¢ IEEE 802.11b: Works at 5.5 and 11 Mbps in 2.4 GHz band, ratified in 1999. à ¢Ã¢â€š ¬Ã‚ ¢IEEE 802.11e: MAC enhancements for Quality of Service (QoS), work ongoing.( Stallings,2005) 2.3) There are four physical components standards for 802.11 network : Access point- Station- -Wireless Medium -Distribution System The basic structure block ,of the WLAN network is the 802.11 basic service set (BSS). A BSS defines a coverage area where all stations within the BSS connected. There are Two BSS network topologies: Independent BSS (IBSS) Networks Infrastructure BSS Networks The first one, In the independent BSS network stations, as it shown in figure(1) are communication directly with each other. Also its called the IBSS as ad-hoc network, used to communicate all station in infrastructure network together . An ad -hoc network operates from one station to another station immediately, without any help from other device, thats mean no need for permission to access. This operation is working by using the independent basic service set(IBSS) . Figure (1) :Independent Basic Service Set(IBSS) Second an Infrastructure Basic Service Set(BSS) as we can see in figure, (2) is a type of IEEE 802.11 network consists from stations and access point(AP), which are used to communicate all stations by (BSS).This will work when first station is sending the information to AP and than the AP forward this information to station which let the information pass to a wired node and the AP passes to fixed network. This available at (http://msdn.microsoft.com/en-us/library/ff556962(VS.85).aspx) Figure (2):Infrastructure Basic Service Set (http://msdn.microsoft.com/en- us/library/ff556962(VS.85).aspx) 1] what is Fragmentation? and 2] Why we are using this Technology? 2.4) what is Fragmentation? In this section we understand the Fragmentation It is the process of break ­ing apart a packet into smaller pieces. Fragmentation is process that dividing large frame into several shorter frame. Each fragment consists of a MAC Layer header and frame check sequence (FCS), and a fragment number representing its ordered to position within the frame. Because the source station transmits each fragment independently, the receiving station reply with separate acknowledgement for each fragment (Yuguang and Kwon,2003 ) . All fragments are generate with equal size at same time, and all fragments will not change until they are transmitted in both PCF and DCF. 2.5) Why we are using this Technology? Using this technology because the Wireless LANs have high bit error rates. The probability of lasing frame is much higher for wireless links. 802.11 uses fragmentation to reduce the frame error rate. 2.6)The advantages and disadvantages of fragmentation: Advantages : To reliability of data exchange between the stations. The uses fragmentation to reduce the frame error rate and fragmentation for larger sized packets improves . Disadvantage: fragmentation will increase the overhead. (Tamer Khatteb,2009) 2.7) Distributed Coordination function (DCF) In 802.11, DCF also provides an optional way of transmitting data frames that involve transmission of special short RTS and CTS frames to the transmission of actual data frame. As shown in Fig(.3) an RTS frame is transmitted by a station, which needs to transmit a packet. When the destination receives the RTS frame, it will transmit a CTS frame after SIFS interval immediately following the reception of the RTS frame. Figure(3) Fragmentation The RTS/CTS access method (Anon.,2003) The source station is allowed to transmit its packet only if it receives the CTS correctly. Note that all the other stations are capable of updating the NAVs based on the RTS from the source station and the CTS from the destination station, which helps to combat the hidden terminal problems In fact, a station able to receive the CTS frames correctly, can avoid collisions even when it is unable to sense the data transmissions from the source station. If a collision occurs with two or more RTS frames, much less bandwidth is wasted when compared with the situations where larger data frames in collision.(Haitao ,et al.,2002) 2.8) The Fragmentation operation: A 802.11 data link layer is divided in two sub layers Logical Link Control (LLC) and Media Access Control(MAC). In 802.11, a MAC service data unit (MSDU) could be divided into a sequence of smaller MAC protocol data unit (MPDUs) as it (shown in figure 4). Fragmentation creates MPDUs smaller than the original MSDU length to increase the reliability, by increasing the probability of successful transmission of the MSDU in cases where channel characteristics limit reception reliability for longer frames. Fragmentation is able at each immediate transmitter. The process of combine MPDUs into a single MSDU is called as defragmentation . Defragmentation is adept at each immediate destination Only MPDUs with a unicast receiver address will be fragmented. Broadcast multicast frames shall not be fragmented even if their length exceeds a Fragmentation Threshold When a directed MSDU is received from the LLC with a length greater than a Fragmentation Threshold the MSDU shall be fragmented. The MSDU is divided into MPDUs. Each fragment is a frame no larger than a Fragmentation Threshold. (Yuguang and Kwon,2003 ). Figure( 4) MSDU divided into several MPDU. (Yuguang and Kwon,2003 ). ) Point Coordination function (PCF):2.9 PCF is working in combination with DCF as it shown in figure (5). PCF works suitable for high traffic load, In PCF, the AP acts in the role of the point coordinator, and it controls the medium access, If point coordinator hears there is no traffic after PIFS time gap, it sends out beacon frame Field to indicate length of time that PCF (polling) will be used instead of DCF (contention) during this time.(Stalling,2008) receiving stations must stop transmission for that amount of time The period during which PCF operates is called the contention-free period (CFP). Before the CFP begins, the AP operates under DCF, but it makes use of the priority inter-frame space (PIFS) to take hold the medium, and then sends out a beacon packet containing the duration of the CFP.(Stalling,2008) Figure (5). combination DCF PCF .(Stalling,2008) The fragmentation operation in PCF is same as DCF,but in PCF conation free period making different ,but because the DCF working with Contention period (CP) and PCF working with Contention free period(CFP) . (Yuguang Kwon,2003 ). There are some limitations on PCF which directly effetely the fragmentation, one of these limitation is the binary exponential back off , the frame need to wait even the medium is free ,because the binary exponential back off will double the random number from 15 to 1023 till the medium will be free, so this can effect the retransmit the frame in fragmentation . Other limitation in PCF has been designed to support time-limited for poor QoS performance. In particular the central pooling scheme is inefficient and complex which causes fall of the performance of PCF high-priority traffic under load, when a free station is allowed to send a frame of length between 0 and 2346 bytes, it introduce the difference of transmission time. (Dillip.2006). 2.1.0)Analysis The earliest work in data fragmentation IEEE802.11: In this section we will analysis ,In this paper(Abhishek,2003) we can analysis that polling in PCF causes overhead . In PCF, point coordinator (PC )is a central coordinator that schedules channel access for all other polling able stations in CFP. PC maintains list of poll able nodes in BSS. At beginning of CFP it polls all stations in Round Robin fashion. Nodes receiving poll respond back, either by transmitting data or there is no data frame. If station has no pending data, then it sends no frame. If station fails to do either then its result in polling time out at PC and PC resumes polling. When most stations have pending data, in order polling provide to ordered channel access and this can reduces collisions. But when few stations have pending data and rest are silent, this polling operation becomes major overhead, It adds unnecessary delay for stations with data, due to unsuccessful poll attempts for stations, with no pending data. For this reason resulting in throughput decreasi ng. Form the figure(6) we compares the overall throughput of network with 32 and 64 nodes having 16 nodes that have data to transmit. We can analysis that Effect of polling overhead is clearly visible(Abhishek,2003) Figure 6: the effect of (polling overhead )on network throughput From this paper, we can find the solution for pervious paper (Abhishek ,2003),by analysis that the overhead in PCF fragmentation is high ,so instead of allowing the transmission of multiple packets with a high data rate ,its possible to make MPDU large size to reduce the overheads caused by multiple packets transmission when channel condition is good. In Literature Review analysis we can describe it more clear(Yuguang and Kwon,2003 ). As we understand from this paper, that voice packets transmitted by use of PCF mode ,According to our analysis, PCF mode can well support packetized voice transmission using echo canceller fragmentation ,when the load are fragmented into small packets ,large fragment size such as 2000 or 2304 bits dose favour to voice traffic at the available bandwidth for data transmission.(Xiyan,al.,2003) In this paper ,we can analysis that, they propose a new rate adaptive MAC protocol with adynamic fragmentation. The major advance is the use of multiple fragmentation thresholds, for different rates to generate a new fragment from (remaining) MSDU only after the rate for next transmission is selected. With this scheme, the nodes with good channels can transmit more data than the ones with bad channel.( Byung,al.,2005) In this paper ,several methods been used to improve wireless network performance ,the result indicate as we can see in the figure (7),that the effect of fragmentation threshold can increase throughput and improve the wireless network performance, but how, the answer is when the bit error rate selected to be and the fragmentation threshold to be 256 bytes or 512 bytes, the result show that there is no any major effect on the network performance.(Walid Ajlouni,2006) figure (7),Effect of fragmentation, ( Walid Naim,2006) This paper ,proposes an adaptive control algorithm to tune the performance of IEEE802.11wireless LANs, so that traffic demands with different characteristics will be handled mostly by the MAC protocol that fits them. The algorithm aims is control the percentage of CFP duration within a super frame by measuring the throughput in PCF mode.(James,al.,2003) Chapter 3 Literature Review analysis T In this section we will be analysis ( 3.1 he out come from literature Review analysis: -Fragmentation It is the process of break ­ing apart a packet into smaller pieces. Fragmentation is process that dividing long frame to several shorter frame, Each fragment consists of a MAC Layer header, frame check sequence (FCS), and a fragment number indicating its ordered position within the frame. (Yuguang Kwon,2003 ). -The main reason we are using fragmentation is because the Wireless LANs have high bit error rates. -The period during which PCF operates is called the contention-free period (CFP). When most stations have pending data, in order polling provide ordered channel access and reduces collisions. But when few stations have pending data and rest are silent, this polling mechanism becomes major overhead, It adds unnecessary delay for stations . There are some limitations on PCF which directly effetely the fragmentation, one of these limitation is the binary exponential back off , the frame need to wait even the medium is free ,because the binary exponential back off will double the random number from 15 to 1023 till the medium will be free, so this can effect the retransmit the frame in fragmentation .(Class lecture ,Simulation Network Multimedia) 3.2 ) What will be solutions for Some Of above problems: 1) When there will be high overhead in PCF fragmentation is, so instead of allowing the transmission of multiple packets with a high data rate ,its possible to make MPDU large size to reduce the overheads caused by multiple packets transmission when channel condition is good. 2) when the bit error rate selected to be or the fragmentation threshold to be 16 bytes or 256 bytes, the result show that there is no any major effect on the network performance, so this maybe will be one of in our design and experiment we will select the above bit rat error than simulated it and observe the result.( Walid Naim,2006) 3) We go for IEEE 802.11e which introduces new coordination function called as a Hybrid Coordination Function (HCF) that is only useful for QoS network. The HCF supports channel access mechanisms, Enhanced Distributed Channel two additional Access (EDCA) for contention-based and HCF Coordination Channel Access (HCCA) for contention-free. And this stander will solve all problem with Polling and CW, which effect on fragmentation in PCF. ) Future Work:3.3 During my research i found that there is new standard been developed in 2007 , it know as IEEE 802.11e. To the best of our knowledge, there is very little literature , that deals with polling overhead in PCF .Other People have mentioned the problem earlier and there also come with some proposed solution to deal with it. also that people have mention the importance of polling for providing QoS service in IEEE 802.11 WLAN. New upcoming standard for QoS, IEEE 802.11e its called HCF (Byung,al.,2005) Chapter 4 Research Problem As i mention earliest the reason of selecting the study of data fragmentation effect in IEEE 802.11 under PCF mode is , is because in my organization they are looking for wireless network technology ,which can provide such applications like for delivering traffic for real-time applications such as Voice and data. There are some limitations on PCF which directly effetely the fragmentation, one of these limitation is the binary exponential back off , the frame need to wait even the medium is free ,because the binary exponential back off will double the random number from 15 to 1023 till the medium will be free, so this can effect the retransmit the frame in fragmentation . There for i found that IEEE 802.11 under PCF mode ,will not satisfy my Chapter 5 Design and Experiment Setup In This section i will be doing simulation , by using OPNET software as we can see in figure (8) to design and evaluate the performance of the IEEE 802.11 MAC protocol for wireless LANs. The aim of the project is to study the effect of data fragmentation in IEEE802.11under PCF mode. The main objectives of this experiment is to Study the effect of data fragmentation in PCF by choosing different bit rate error and observe the major effect on the network, as we analysis that using low bit error rate ,and give fragmentation value 256 bytes or 512bytes ,the result must show that there will be will no effect on the data transmission or on network performance. We can also do measuring response time (seconds) for PCF with 256 fragmentation and fixed data rate 5.5Mbps, and for page response time (seconds) for PCF with 256 fragmentations with fixed data rate 11Mbps.Finaly Compare the result obtain. Figure 8: WLAN Setup diagram in OPNET Chapter 6 Conclusion During my working in this project I have identify the effect of data fragmentation in IEEE802.11 under PCF in wireless network. I come out that this standard will help me in my organization to be used in library office only. The probability of lost frame is much higher for wireless links. Thats why fragmentation is used to Reduces amount of time medium is in use and Reduces probability of collisions .The IEEE 802.11 WLAN has two different channel accessing mechanisms, namely, the distributed coordination function (DCF) and point coordination function (PCF). We understand that When most stations have pending data, sequential polling provide ordered channel access and reduces collisions. But when few stations have pending data and rest are silent, this polling mechanism becomes major overhead, It adds unnecessary delay for stations with data. Also we understand that when there will be high overhead in PCF fragmentation is, so instead of allowing the transmission of multiple packets with a high data rate ,its possible to make MPDU large size to reduce the overheads caused by multiple packets transmission when channel condition is good. Anew standard has been developed in 2007 , it know as IEEE 802.11e. which support QoS. and can solve polling overhead in PCF. The References Books : Stalling,W.William.,2008.Data and computer communications 8 ed published by Dorling Kindersly(India) Pvt,LTD 482, F.I.E Delhi, India. Stalling, W,Willim., 2008, Wirless communications Network second ed published by Asoke K. Ghosh (India) Delhi, India. E-Books: Ross, John.,2008. Book of Wireless : A Painless Guide to Wi-Fi and Broadband Wireless (2nd Edition). San Francisco, CA, USA: No Starch Press, Incorporated, p 15. Available at: http://site.ebrary.com/lib/caledonian/docDetail.action?docID=10218384p00 =a%20painless%20guide%20wi-fi%20broadband%20wireless%20(2nd%20edition). Journal Papers: Tamer, M Samir ,K .,2009.Performance Analysis of Wireless Local Area Networks ,WLANs A thesis submitted to the Faculty of Engineering at Cairo University in partial fulfillment of the requirement for the degree ofMASTER OF SCIENCE. Yoon Hougwon Kim Jeonge. ,2003. Data fragmentation scheme in IEEE 802.15.4 wilerlss sensor network, Department of computer Scinse and Engieenring , Korea Unifersity Dillip, K., 2006.Quality of Service Provisioning with modified IEEE 802.11 MAC Protocol, Department of Computer Science and Engineering National Institute of Technology Rourkela Rourkela-769 008, Orissa, India Byung,S, Younggoo, K. ,2003.Throughput Enhancement Through Dynamic Fragmentation in Wireless LANs ,Student Member, IEEE, Yuguang Fang, Senior Member, IEEE, Tan F. Wong, Senior Member, IEEE. Abhishek ,G. , 2003.Dynamic Adaption of DCF and PCF mode of IEEE 802.11 WLAN, School of Information Technology, Indian Institute of Technology, Bombay . Xiyan, M ,Tamio, S.,2003.,Performance Analysis of Packetized Voice Transmission with PCF in IEEE802.11Wirelessnetwork, Dept. of electronic Engineering .Tsinghu University ,Beijing ,China.2003. Shakil ,A.,2007. Effect of Fragmentation in WLAN Systems with Interference Problems. College of Information Technology University. [emailprotected] .UAE James X.Dong,S.,2004 Mustafa Ergen Improving the Aggregate Throughput of Access Points in IEEE 802.11 Wireless LANs, and Anuj Puri Department of Electrical Engineering Computer Science University of California at Berkeley. Ziouva E. and Antonakopoulos T.2003., Efficient Voice Communications over IEEE802.11 WLANs Using Improved PCF Procedures. Walid ,HNaim ,A.,2006 Performance Enhancement of Wireless Local Area Networks,Dept. of Computer Science,Amman Arab University for Graduate Studies,P 0 Box 2925, Amman 11821, Jordan. Web Page:URL http://msdn.microsoft.com/en-us/library/ff556962(VS.85).aspx

Residential Schools Essay

Long before Europeans came to North America, aboriginal people had a highly developed system of education. There was a great deal for aboriginal children to learn before they could survive on their own. Aboriginal elders and parents passed on not only survival skills to their children, but their history, artistic ability, music, language, moral and religious values. When European missionaries began to live amongst aboriginal people, they concluded that the sooner they could separate children from their parents, the sooner they could prepare aboriginal people to live a civilized (i. e. European) lifestyle. Residential schools were established for two reasons: separation of the children from the family and the belief that aboriginal culture was not worth preserving. Most people concluded that aboriginal culture was useless and dying and all human beings would eventually develop and change to be like the ‘advanced’ European civilization. Early residential schools were similar to religious missions. Later, the mission-run schools were administered jointly by Canadian churches and the federal government, and for a number of years, residential schools became official Canadian policy for the education of Indian. . . Provincial education curriculums did not change to reflect the educational needs of aboriginal children. The elders in fact seen a major change in the way the children were acting, they would refuse to do chores and would often talk back and often became violant. The school demanded very little in comparison. Loneliness, sickness, confusion and abuse all had to be borne in lonely silence. Aboriginal children continue to have difficulties fitting in to the existing schools, which are still designed around a culture alien to their own. They were issued clothes and assigned a bed number. Aboriginal people have demanded, and received, official apologies from the Anglican, United and Roman Catholic churches which operated residential schools. All of this must have been a staggering shock to the new â€Å"student† . Many things combined to make the experience difficult for young aboriginal children. After several years away at school, children often found it difficult to speak their mother tongue. The residential school experience continues to plague First Nations education. The white man’s school contradicted everything these aboriginal children had learned at home. â€Å"The organization of the schools and the content of the curriculum conveyed to aboriginal children that the human values, the political institutions, the spiritual practices and the economic strategies of other Canadians were infinitely superior to the â€Å"primitive† ways of their traditional lifestyles. † Students began to believe that the ceremonies and rituals which harmonized the spiritual and social life of the community and gave its members a sense of personal significance and group identity, were â€Å"heathen† and â€Å"the work of the Devil.

Role of Literature in the Age of Technology

Literature refers to the realm of letters and the writings of a particular period, mostly those whose value lies in the beauty of form or emotional effect. Technology is the science of the industrial arts. Scientists have played an important role in promoting human welfare, but the benefits of science may not have reached the masses, at any rate in ample measure, without technological devices and practical applications. We live in the world of both science and technology and many people, who take a rather superficial view of things, have begun to feel that in the technological world of tomorrow the role of literature seems poor.In fact, literature in its pure form is believed to have little relation with science and technology. Science provides knowledge and power and both science and technology affect human life at several points, though the extent and utility of the applications are determined by our culture, our wisdom and our priorities. Literature reflects the moods and emotions of the times in which it is produced; it is conditioned by the reflexes which, in turn, are created by the impact of science and technology.Modern technology increasingly dominates the world, and the domination is likely to become more pronounced in future, because of the fast developments tending to subdue creative human thinking and expression. But the belief that literature would have no place in future and in futuristic calculations is erroneous. There is no reason to believe that the mechanical way of life, in which our actions are governed more and more by computer culture and electronic calculators of all types, will destroy the talent of writers, authors, poets, biographers and artists.Technology does not discourage natural, multi faceted talent; rather, it generally promotes the climate for expressions of talent in countless channels. All round prosperity helps a great deal in creating literature of lasting value, and it is technology which has made many countries wealthy and prosperous. Jawaharlal Nehru cautioned us some four decades ago that it was only through the growth of technology that our country would become prosperous.In some cases technological development and automation may cause misery, through the resultant unemployment, for instance. But it has to be noted that both science and technology also provide additional avenues for employment; countries which boast of maximum employment, or nearly so, are those which are technologically advanced. In fact, our country may go down, instead of progressing fast, if we do not keep pace with technological developments and march in step, as far as possible, with the industrialised and technologically progressive nations.It is not only for the sake of the material benefits, the comforts and conveniences of life that we must opt for the latest technological processes, even by discarding our traditional practices, but for our art and literature, too, we shall have to make the best of technology, which w ould enable talented people to put in their best in art and literature. Some people think and they have a reason for doing so, that since science demolishes faith and tradition, it tends to produce scepticism, anxiety and even tensions, and it doubts everything, even cherished values.Science has eliminated superstitions. Technology helps to provide weapons of war; war stimulates technologists, but it depresses the artists and those who prepare literary pieces. Sensitivity and the urge to create new masterpieces get suppressed; reckless destruction, bloodshed and hostilities ruin the very climate that helps to create literature and artistic masterpieces. Culture and literature, after all, indicate the cultivation of man's inner nature.Culture prompts men and women to seek perfection; they are not motivated by curiosity and the endless sense of enquiry which characterise scientists and technologists. Literature expresses feelings and innermost thoughts and ambitions, while technology has other ends and other fields to explore. Literature may at first appear to be out of place in a technological milieu, but surely scientists and technologists do not encroach upon the field of literature. There seems to be no reason why both literature and technology cannot flourish side by side.A society that is highly progressive technologically may also become rich in literature. We may take the example of the world's most industrially advanced country and the mightiest military power, the USA, where technology has registered unprecedented achievements and yet the USA has produced rich literature. Technology results in affluence and prosperity and economic prosperity promotes good literature and masterpieces in the arts. So there is no contraction involved. It is only during war and the all out preparations for war, that literature gets a setback.Science and technology, it has been truly said, have radically altered the face of civilisation, but nothing, not even the most sophi sticated mechanical devices and the most fruitful applications of new inventions, can change human nature or replace human being, who must indeed remain in effective command of all scientific inventions and their day-to-day application. Technology has created robots, artificial intelligence in the shape of â€Å"thinking computers† which can read, translate, interpret and give decisions with amazing speed and accuracy.But not even the most sophisticated technological advances can by themselves produce literature—poetry, prose, plays, novels and stories. In a sense, science and technology may be said to be of direct assistance in promoting literature, because they help to create leisure by introducing labour saving and time saving devices and by eliminating drudgery as well as duplication of effort. The leisure thus created can be put to literary pursuits. In such a context, the talk of a contradiction between technology and literature is not well founded.Scientific kno w how may thus be viewed as technology which, examined dispassionately, has an important bearing on arts and literature. Good literature makes a lasting impact on the human mind; it entertains, instructs and ennobles the spirit of human beings; it does not debase or corrupt the mind in any way, and it certainly does not lead to destruction of any section of mankind. Science and its handmaid, technology, however, have placed in the hands of man vicious and highly destructive tools in the shape of lethal weapons the like of which he has never had before.Literature builds, but technology, if misused by vicious statesmen and politicians may cause havoc on a massive scale, destroying both litterateurs and technologists without discrimination. Technology does make for concentration and centralisation of economic and political activity. A person's individuality, sense of fraternity and selflessness tend to get eroded. Where there is less patronage of art and talent, there is bound to be le ss of literature of permanent value, because the right spirit and mood are not there to promote it.The depersonalisation of modern life which, it appears, will get stronger as the years pass, is likely to discourage writers and poets; misery, anguish and a generally noisy atmosphere are hardly conducive to the production of sound literature. But we need not give up all hope of a better world tomorrow, from the standpoint of culture and literature, simply because science and technology tend to predominate over human values. It is within the power and capacity of man, provided he exercises his sound judgment and pursues the right priorities to shape a better world, where literature flourishes along with industry and technology.

Post War Of World War II - 1142 Words

Throughout Art History, it is apparent that techniques are established and flaunted to create some vivid image of a story, or a message. Up to the post war of World War II, art has delivered a scene which can be interpreted through context clues such as; current philosophies, current events, and folk-lore. Then, mainstream art had undergone a significant change in theme post World War II. New York City, United States of America, became the art capital of the world. Why? It is arguably due to Abstract Expressionist art and Pop Art known as Modernism. Modernism completely new to the world, and both of which abandoning some common core themes to art. Two famous artists whom facilitated and practiced such dramatic alterations in art culture are Paul Jackson Pollock, or just known as Jackson Pollock, and Andy Warhol. At first glance, someone with the an eye trained in art history and lore would look upon some of Jackson Pollock s art and think, â€Å"How is this even art?† Maybe ev en said with some foul language. Some may even take it as an insult to Art History. â€Å"How can someone completely disregard the divine techniques in which our classic art is founded upon?† Well, this is all in the perspective of following the suppressive laws of a mind which may not be be susceptible and/or unwelcoming to change. At first glance, Jackson Pollock s controversial work, â€Å"Number Thirty-one† is a messy, unsuspecting work of art. â€Å"Number Thirty-one† labors your eyes to follow the nearlyShow MoreRelatedThe Post War World War II1216 Words   |  5 PagesThe post-war world was one of complete ruin. More than 40 million Europeans died and at least 25 million of them were civilians that had been killed in bomb raids, concentration camps, and during famine or starvation. Cities, towns, and villages on the home fronts were destroyed and nothing remained of many homes. Because of all of the distress, thousands of people all turned to their gover nments for assistance. Unfortunately for almost everyone in Europe and Japan, their governments had all failedRead MoreThe Post World War II1128 Words   |  5 PagesAfter World War II ended in 1945, many significant changes to American society began to occur. Some of these major changes helped shape what the U.S. is today and include the Baby boom, mass suburbanization, and mass consumerism. The Post-World War II era is defined by these changes in U.S history and culture. In this Post-World War II era, social conformity became the most ideal way of life. Every citizen wanted the same thing, this is known as the American Dream. The American Dream consistRead MoreGermany Post World War II963 Words   |  4 Pages World War II caused many problems for Germany. Since the war, Germany has had to rebuild and clean up many towns. Germany did many tasks after the war to help with the war effort. Many citizens loved ones died causing many grievances within the country. The people of Germany all want to reconstruct there country because it is in ruins. In order for the country to become better and more sanitary they have a division of lands, change in government and many people cleaning up. The German peopleRead MoreA Society Post World War II1169 Words   |  5 PagesLiving in a society post World War II where social revolution is said to be unnecessary, there was solidity on Americans in the 1950s to conform to certain expectations and values. During the peak of the Cold War, any one who did not share the same values would be accused of being a communist. These common values that Americans believed in the 1950s were a liberal consensus that described America as an unflawed society that worke d and did not suffer from any major struggles. The liberal consensusRead MorePost World War II Women991 Words   |  4 PagesPost World War II women were marginalized and endured several limitations throughout the 20th century as a result of rigid gender roles, minimal education and job opportunities. My family’s history demonstrates the rarity of divorce and separation. However, the emergence of divorce perpetuated years to follow, infringing upon social norms promoting controversy. Fortunately, Canada introduced new reforms to minimize economic hardship for single families, such as welfare. Thus, prior to the 1920’sRead MorePost World War II Size1560 Words   |  7 PagesOn Monday, 24 February 2014, Secretary of Defense Chuck Hagel announced massive cuts to the size of the armed services, slashing the army to its pre-World War II size. (breithbart.com) Hagel’s plan called for a 25% reduction in manpower by 2019. Historically, these cuts equate to a perceived failure of will power of the American government by its global enemies. Such cuts are sure to decrease the readiness posture of fighting units across the military. First order effects from cuts to fundingRead MorePost World War II : The Soviet Union880 Words   |  4 PagesPost World War II, both the United States and the Soviet Union were fearful of fighting each other directly from fear of nuclear weapons and mass destruction (D. Johnson, P. Murray). Instead, they fought each other by p articipating in wars on separate parts of the world. Cold War tensions between the United States and the Soviet Union constantly fluctuated due to both sides trying to influence political and economic developments around the world (D. Johnson, P. Murray). Following World War II, theRead MoreLife During Post World War II912 Words   |  4 PagesI. Life in post-World War II Canada A. Many people immigrated to Canada following the war. Most immigrants settled in the cities such as Toronto, Montreal, and Vancouver. B. The â€Å"baby boom† began as Canadian soldiers returned from the war, married, and started families. C. On March 31, 1949, Newfoundland joined Canada forming the tenth province of our country. D. In 1949, the construction of the trans-Canada highway was begun. E. In June of 1959, the St. Lawrence Seaway opened connecting the GreatRead MorePost World War II American Society512 Words   |  2 PagesPost World War II American Society American had been isolationist in keeping the affairs to itself. When the policy of Good Samaritan did not work out as America failed to keep the harmony between Europe countries, it became substantial that external concerns are devastating. Any idea of movement to stop the tyranny in Europe was even opposed strongly as a retaliation response to the failure. Nonetheless, the long tradition of isolationism finally ended when the World War II disrupted. The relinquishmentRead MoreJapanese Economic Development Post World War Ii2579 Words   |  11 PagesWorld War II left many powerful nations in smoke and rubble. The deconstruction of many countries gave them the chance to rebuild their cities and economies. No country took more advantage of this opportunity than Japan. Japan was a huge militaristic power in World War II . Their aggressive behavior caused them to be stripped of their military and their power for self rule. The demilitarization of Japan changed the countrys focus from world militaristic domination to world economic domination