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

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3.3.1.4.4. HR-DSSS and CCK Figure 3-4 DSSS PLCP The original modulation method (Barker code) used in DSSS, for 802.11, only achieved the speeds of 1 and 2 Mbps. For commercial use, this is not an acceptable amount. In the data stream, each barker word carries one or two bits depending on the data rate. To improve the speed, it is necessary to increase the capacity of each symbol. That means more complicated phase angle changes. For example, the DQPSK receiver could at least detect four cycle phase differences. More cycle phase differences will cause the smaller phase changes. It ends up with the need of a highly accurate and costly receiver. Therefore, the next standard 802.11b had a different modulation method known as Complementary Code Keying (CCK). This method splits the data stream into code symbols composed with 8 bits. By a complex mathematic procedure, the CCK can encode four or eight bits per code word with 8-bit code symbols. Also, this procedure can help receivers to identify different codes easily, even in interference or a multipath fading environment. By using the CCK process, the speed can reach 5.5 Mbps or 11 Mbps. The process of CCK is quite similar to the DS chipping process. Figure 3-5[17]. The difference between them is that CCK does not use the static repeating code word, as for example, Barker Code. The code word is converted from the data. These code words are used to transmit data and spread the signal. Phase angle also plays an important role here, but this time it will not cost as much as DQPSK. 18
Figure 3-5 CCK Modulation HR-DSSS PHY is defined as the data rate equal to 5.5 or 11 Mbps. It also contains two parts, PLCP and PMD. PLCP is in charge of framing and PMD is response for transmission. 3.3.1.4.5. PLCP and PMD of HR-DSSS The structure of HR-DSSS PLCP is show in Figure 3-6[17]. It is very similar to DSSS- PLCP, the only difference being in preamble. Its preamble is called short preamble. This kind of preamble could improve the efficiency of PLCP framing. For backward compatibility, the HR-DSSS PMD can support both low (1, 2 Mbps) and high (5.5, 11 Mbps) transmission. The only difference is low speed must uses long preamble while high speed uses short one. In addition, for high speed, the framed data will be encoded by CCK modulation before transmitting. At 5.5 Mbps, each symbol has four data bits and at 11 Mbps, each symbol has eight data bits. Figure 3-6 HR/DSSS PLCP Framing 19
Page 1 and 2: 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: Noise Codes). The most powerful con
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 and 64: Encryption Figure 4-4 PKM Protocol
Page 65 and 66: 4.3.2. IEEE 802.16e-2005, the newes
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
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Table 5-4 Cont. 71
Page 85 and 86:
5.1.3. Analysis The FSU wireless ne
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since the January 2006. The populat
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Table 5-5 Parameters of WLAN and Me
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Table 5-6 Features of Nortel Wirele
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• -101 dBm typical @ 1 Mbps Recei
Page 95 and 96:
Operating environment specification
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uilding density, high population de
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epeater r is developping and it wil
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Figure 5-17 WiBro Features The data
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Figure 5-19 U-RAS Premium Figure 5-
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In KT’s recent report, 60% of sub
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Figure 5-21 An Example Application
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Name Parameters Standard Table 5-10
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WiFly used Wi-Fi to cover 60% of th
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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
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Network Operations and Management S
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