A comparison of wi-fi and wimax with case studies - Florida State ...

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4.3.1.2.4.2. Overall Analysis Figure 4-5 Encryption Frame Structure and Process Learning from the experience from IEEE 802.11, the IEEE 802.16 working group faces security threats both in the MAC and PHY levels. 802.11 only has protections in the MAC level cannot present against attacks from PHY-Level. 802.16 progression has many good functions, however it also brings with it an increase of threats to users The initial standard IEEE 802.16-2001 requires an attacker to put real equipment between SS and BS and also operate at a frequency of 10 to 66 GHz. The IEEE 802.16e adds mobility to the standard; however it creates a security risk. Now, an attacker’s physical position is not really constrained and the management messages are much weaker than IEEE 802.11. With radio transmission, there is a great risk. Anyone who has a proper well located receiver can intercept the channel. So the designers have to establish a safety mechanism. The other threat is that anybody who has a correctly configured radio transmitter can access the wireless network. Through this weakness, an attacker can make up or modify frames from authorized organizations. Therefore there must be a procedure to protect the transmitting data. Furthermore, the interference and distance may also give attackers a chance to intrude the system or two systems which cannot connect to each other directly. Thus, how to protect a system and examine the received data are also very important to designers. 52
4.3.2. IEEE 802.16e-2005, the newest standard 4.3.2.1. OFDMA-PHY 4.3.2.1.1. Background OFDMA (Orthogonal Frequency Division Multiple Access) is the main difference of 802.16e from other 802.16 standards. Most of new improvements and design are based on it. This method is deeply related with FDMA (Frequency Division Multiple Access). By using FFT/IFFT, FDMA can divide and combine the baseband in an orthogonal way. In OFDMA-PHY, the subchannels are a minimum frequency resource-unit assigned by a base station. Thus different subchannels can be allocated to different users as a multiple-access mechanism. The IEEE TGe introduces scalability to OFDMA which can help provide best performance in a channel with bandwidth between 1.25MHz to 20MHz. for both fixed and mobile service. Also it can lower the cost of system. [50][53] The FFT size in OFDMA-PHY is scalable from 128 to 2048. When the bandwidth increases, the FFT size is increased too, but the subcarrier interval is fixed as 10.94 kHz. This also keeps the OFDM symbol duration fixed. The 10.94 kHz interval is the best choice for balancing between the delay-spread and Doppler spread requirements for operating in fixed and mobile environments. This interval allows the delay-spread up to 20µs and mobility speed up to 125 kmph in 3.5 GHz band. The FFT size 128, 512, 1024 and 2068 are used when the channel bandwidth are 1.25, 5, 10 and 20 MHz, respectively. The 256 bits OFDM is included in the OFDMA-PHY, so the mobile-WiMax is backward compatible with fixed-WiMax, when the FFT size is 256. [50][53][106][120] – [123] Table 4-3 is the recommended scalability parameters for system. 4.3.2.1.2. Frame structure OFDMA supports many different frame sizes to fit the need of various applications and models. There are three types of OFDMA subcarriers: [53][102][103][124] – [126] 1. Data subcarriers for data transmission. 2. Pilot subcarriers for various estimation and synchronization purposes. 3. Null subcarriers for no transmission at all, used for guard bands and DC carriers. In different subcarrier allocation modes, the pilot allocation is performed differently. For DL (Downlink) Partially Used Subchannelization (PUSC) and all UL (Uplink) modes, the set of subcarriers of data and pilot is first sliced into subchannels, and then the pilot subcarriers are allocated by each subchannel. For DL Fully Used Subchannelization (FUSC), the pilot 53
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THE FLORIDA STATE UNIVERSITY COLLEG
Page 3 and 4:
TABLE OF CONTENTS List of Tables…
Page 5 and 6:
5. Case study…………………
Page 7 and 8:
LIST OF FIGURES Figure 2-1 The Evol
Page 9 and 10:
LIST OF ABBREVIATIONS Abbreviation
Page 11 and 12:
PSS Portable Subscriber Station 89
Page 13 and 14: CHAPTER ONE 1. Introduction The cel
Page 15 and 16: Table 1-1 Cont. 802.3an 2006 10GBAS
Page 17 and 18: 2.1. Introduction CHAPTER TWO 2. 3G
Page 19 and 20: 2.3. Development 3G has been in dev
Page 21 and 22: 2.5. Conclusion WAP (Wireless Appli
Page 23 and 24: IEEE 802.11n is the newest standard
Page 25 and 26: Table 3-3 Cont. 10 2.457 X Y Y Y Y
Page 27 and 28: 3.3.1.2. PLCP and PMD The physical
Page 29 and 30: Noise Codes). The most powerful con
Page 31 and 32: Figure 3-5 CCK Modulation HR-DSSS P
Page 33 and 34: other problem is inter-carrier inte
Page 35 and 36: Tab ble 3-5 OFDDM Modulaation and D
Page 37 and 38: and contains DSSS, CCK, PBCC (Packe
Page 39 and 40: 3.3.2. MAC Layer 3.3.2.1. Introduct
Page 41 and 42: Virtual channel sensing he other me
Page 43 and 44: SIFS (Short InterFrame Spacing) Fig
Page 45 and 46: Figure 3-20 WEP Frame and Operation
Page 47 and 48: 3.4.2. MIMO (Multiple-Input/Multipl
Page 49 and 50: 4.1. The background of IEEE 802.16
Page 51 and 52: The working groups of WiMax Forum a
Page 53 and 54: Table 4-1 Thee Basic Datta of IEEE
Page 55 and 56: Figure 4-1 The Layer Structure of I
Page 57 and 58: codes ( (CTC) and low densityy pari
Page 59 and 60: 4.3.1.2.2. AAS (Advanced Antenna Sy
Page 61 and 62: Best-effort service (BE) This schem
Page 63: Encryption Figure 4-4 PKM Protocol
Page 67 and 68: transmiission, the aadjacent cellls
Page 69 and 70: the uplink bandwidth periodically f
Page 71 and 72: Figure 4-7 Coverage and Capacity fo
Page 73 and 74: CHAPTER FIVE 5. Case study This cha
Page 75 and 76: increased bandwidth, fixed connecti
Page 77 and 78: Figure 5-3 Landis Green Figure 5-4
Page 79 and 80: Table 5-2 Xirrus XS-3700 AP Technol
Page 81 and 82: • Automatic Tx power selection
Page 83 and 84: Table 5-4 Cont. 71
Page 85 and 86: 5.1.3. Analysis The FSU wireless ne
Page 87 and 88: since the January 2006. The populat
Page 89 and 90: Table 5-5 Parameters of WLAN and Me
Page 91 and 92: Table 5-6 Features of Nortel Wirele
Page 93 and 94: • -101 dBm typical @ 1 Mbps Recei
Page 95 and 96: Operating environment specification
Page 97 and 98: uilding density, high population de
Page 99 and 100: epeater r is developping and it wil
Page 101 and 102: Figure 5-17 WiBro Features The data
Page 103 and 104: Figure 5-19 U-RAS Premium Figure 5-
Page 105 and 106: In KT’s recent report, 60% of sub
Page 107 and 108: Figure 5-21 An Example Application
Page 109 and 110: Name Parameters Standard Table 5-10
Page 111 and 112: WiFly used Wi-Fi to cover 60% of th
Page 113 and 114: BIBLIOGRAPHY [01]. IEEE 802.11 offi
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[37]. Sun, Y.; "Bandwidth-efficient
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[88]. Mineno T.; Babji T.,"Issues a
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[117]. Yun Z.; Yuguang F., "Securit
Page 121 and 122:
Network Operations and Management S
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