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HANNAM UNIVERSITY Chapter 14 LAN (Wireless LAN)

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Presentation on theme: "HANNAM UNIVERSITY Chapter 14 LAN (Wireless LAN)"— Presentation transcript:

1 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr Chapter 14 LAN (Wireless LAN)

2 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr 2 14 14 14.1 IEEE 802.11 14.2 14.3

3 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr 3 14.1 IEEE 802.11 Topics discussed in this section: IEEE has defined the specifications for a wireless LAN, called IEEE 802.11, which covers the physical and data link layers. Architecture MAC Sublayer Physical Layer

4 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) IEEE 802.11 LAN (BSS, basic service set) (ESS, extended service set) 4

5 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) 5 A BSS without an AP is called an ad hoc network; a BSS with an AP is called an infrastructure network.

6 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Basic service sets(BSSs) 6

7 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Extended service sets(ESSs) 7

8 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) (NO-Transition Mobility) BSS (BSS-Transition Mobility) ESS (ESS-Transition Mobility) ( ) 8

9 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) MAC layers in IEEE 802.11 standard 9

10 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) CSMA/CA flowchart 10

11 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) CSMA/CA and NAV 11

12 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Example of repetition interval 12

13 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Frame format 13

14 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Subfields in FC field 14

15 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Control frames 15

16 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Values of subfields in control frames 16

17 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Addresses 17

18 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Addressing mechanisms 18

19 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Hidden station problem 19

20 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) 20 The CTS frame in CSMA/CA handshake can prevent collision from a hidden station.

21 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Use of handshaking to prevent hidden station problem 21

22 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Exposed station problem 22

23 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) 23 Use of handshaking in exposed station problem

24 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Physical layers 24

25 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Industrial, scientific, and medical (ISM) band 25

26 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Physical layer of IEEE 802.11 FHSS 26

27 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Physical layer of IEEE 802.11 DSSS 27

28 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Physical layer of IEEE 802.11 infrared 28

29 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr IEEE 802.11 ( ) Physical layer of IEEE 802.11b 29

30 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr 30 14.2 BLUETOOTH Topics discussed in this section: Bluetooth is a wireless LAN technology designed to connect devices of different functions such as telephones, notebooks, computers, cameras, printers, coffee makers, and so on. A Bluetooth LAN is an ad hoc network, which means that the network is formed spontaneously. Architecture Bluetooth Layers Baseband Layer L2CAP

31 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) LAN IEEE 802.15 (PAN, personal area network) 31

32 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) Piconet 32

33 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) Scatternet 33

34 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) Bluetooth layers 34

35 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) (radio layer) 79 2.4 GHz ISM FHSS 1,600 625ms(1/1,600s) (dwell time) 625ms GFSK( ) FSK 1 0 35

36 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) (baseband layer) LAN MAC (time slot) (625ms) TDMA TDD-TDMA(time division duplexing TDMA) 36

37 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) Single-secondary communication 37

38 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) Multiple-secondary communication 38

39 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) Frame format types 1- 626ms – 259ms = 366ms 2- 3×625ms – 259ms = 1,616ms 5- 5×625ms – 259ms = 2,866ms 39

40 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) (access code) : 7 : F. : A. : S. : HEC. : 0~2,740 40

41 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr ( ) ( ) L2CAP data packet format LAN LLC 41

42 HANNAM UNIVERSITY Http://netwk.hannam.ac.kr 42 14.3 14.3


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