1. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Wireless NETWORKS NET 434 Topic No 6 Wireless LANS

2. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Wireless Lans ›A local area network (LAN) is a computer network that interconnects computers within a smaller geographic area such as a home, school, computer laboratory, or office building, using network media.computer network ›A wireless local area network (WLAN) is a wireless computer network that links two or more devices using a wireless medium within a limited area such as a home, school, computer laboratory, or office building.wireless computer networklimited area –It is sometimes called wireless Ethernet. –Some countries, including the United States, the public uses the term WiFi (short for wireless fidelity) as a synonym for wireless LAN.

3. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area IEEE802.11 Architecture ›The IEEE802.11 defines two kids of service sets: –The Basic Service Set ›Ad-hoc BSS -Stationary or Mobile wireless stations -An optional central base station or Access Point (AP) -BSS without the AP is a standalone networks and cant communicate with other BSS (Ad-hoc Architecture/ Mode) ›In this mode/Architecture a collection of computers are associated so that they can directly send frames to each other.

4. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area IEEE802.11 Architecture ›Infrastructure BSS –A BSS with an AP is called the Infrastructure Mode. –In infrastructure mode, each client is associated with an AP (Access Point) that is in turn connected to the other network. ›Example Internet Connection using WIFI –The client sends and receives its packets via the AP. ›Extended Service Set –Several access points may be connected together typically by a wired network called a distribution system, to form an extended 802.11 network. –The distribution system connects the APS in the BSSs and communication between a station in a BSs and outside the BSS occurs via Aps. –Mobile stations (Normal Stations in BSs) and stationary stations (AP stations that are part of a wired LAN)

5. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Summary architecture

6. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Wireless lan configurations

7. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Station Types ›IEEE 802.11 defines three types of stations based on their mobility in a wireless LAN. –No transition (Mobile/Stationary only within a BSS) –BSS-transition (Mobile between two BSS but confined within ESS) –ESS-transition mobility (Mobile between two ESS, No guarantee of continuous service)

8. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Protocol Architecture/Stack ›IEEE has defined the specifications for a wireless LAN, called IEEE 802.11, which covers the physical and data-link layers. –The physical layer corresponds fairly well to the OSI physical layer –The data link layer in all the 802 protocols is split into two or more sub-layers. ›The upper sub-layer of the data-link layer (LLC)-Logical Link Control. -Data link control functions include framing and flow and error control. ›The lower sub-layer, multiple access control (MAC) -In 802.11, the MAC (Medium Access Control) sub-layer determines how the channel is allocated, that is, who gets to transmit next. -When nodes or stations are connected and use a common link, called a multipoint or broadcast link, we need a multiple-access protocol to coordinate access to the link. -Many protocols have been devised to handle access to a shared link. -All of these protocols belong to a sub layer in the data-link layer called media access control (MAC).

9. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Protocol architecture

10. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Physical Layer ›Each of the transmission techniques makes it possible to send a MAC frame over the air from one station to another. They differ, however, in the technology used and speeds achievable. ›All of the 802.11 techniques use short-range radios to transmit signals in either the 2.4-GHz or the 5-GHz ISM frequency bands except the IEEE 802.11 Infrared. ›ISM Frequency bands used for Wireless LANs are unlicensed bands available to any transmitter willing to meet some restrictions, such as radiated power of at most 1 W (though 50 mW is more typical for wireless LAN radios). –Garage door openers, cordless phones, microwave ovens, and countless other devices, operate in the ISM band and compete with laptops for the same spectrum. ›The 2.4-GHz band tends to be more crowded than the 5-GHz band. Less interference in 5-GHz band than 2.4 GHz ›5 GHz can be better for some applications even though it has shorter range due to the higher frequency. –All of the transmission methods also define multiple rates. ›Different rates can be used depending on the current conditions. -If the wireless signal is weak, a low rate can be used. - If the signal is clear, the highest rate can be used. This adjustment is called rate adaptation.

11. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Physical Layer ›IEEE 802.11 FHSS –Frequency-hopping spread spectrum (FHSS) method, –Band-----2.400–4.835 GHz ISM band. –Modulation technique---two-level FSK or four-level FSK –Data rate of 1 or 2 Mbps ›IEEE 802.11 DSSS –Direct-sequence spread spectrum (DSSS) method, –Band-----2.400–4.835 GHz ISM band. –Modulation technique----PSK (BPSK or QPSK) –Data rate of 1 or 2 Mbps

12. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Physical layer ›IEEE 802.11 Infrared –IEEE 802.11 infrared uses infrared light in the range of 800 to 950 nm. ›This does not operate in the ISM band –Modulation technique is called pulse position modulation (PPM). –Data Rates---1 0r 2Mbps ›IEEE 802.11b DSSS –High-rate direct-sequence spread spectrum (HRDSSS) – 2.400–4.835 GHz ISM band. –Data Rates of 5.5 and 11Mbps

13. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Physical layer ›IEEE 802.11a OFDM –OFDM using QAM –5.725–5.850 GHz ISM band. –Data rate –up to 54Mbps ›IEEE 802.11g –This new specification defines forward error correction and OFDM. – 2.400–4.835 GHz ISM band. –The modulation technique achieves a 22- or 54-Mbps data rate. ›IEEE 802.11n –The goal is to increase the throughput of 802.11 wireless LANs. –Data Rates of up to 600 Mbps data rate. –The standard uses MIMO (multiple-input multiple-output antenna) to overcome the noise problem in wireless LANs. ›The idea is that if we can send multiple output signals and receive multiple input signals, we are in a better position to eliminate noise.

14. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Physical Layer-summary

15. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Medium Access Control ›The IEEE 802.11 MAC layer covers three functional areas –Reliable data delivery –Access control –Security ›Like any wireless network, in a wireless LAN physical and MAC layer are unreliable due to noise interference and other propagation effects can result in a loss of significant number of frames. –A number of MAC frames may not be successfully received. ›Reliability at higher layer such as the TCP ›Frame exchange protocol at the MAC Layer –When a station receives a data frame from another station, it returns an acknowledgment (ACK) frame to the source station. –If the source does not receive an ACK within a short period of time, either because its data frame was damaged or because the returning ACK was damaged, the source retransmits the frame.

16. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area MEDIUM access Control ›To further enhance reliability, a four-frame exchange may be used. –A source first issues a Request to Send (RTS) frame to the destination. ›The RTS alerts all stations that are within reception range of the source that an exchange is under way; these stations refrain from transmission in order to avoid a collision between two frames transmitted at the same time. –The destination then responds with a Clear to Send (CTS). ›The CTS alerts all stations that are within reception range of the destination that an exchange is under way –After receiving the CTS, the source transmits the data frame, and the destination responds with an ACK.

17. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area MEDIUM access Control- Access Modes ›The 802.11 working group considered two types of proposals for a MAC algorithm –DCF –PCF ›Distributed Coordination Function –The DCF sub-layer makes use of a simple CSMA/CA (carrier sense multiple access) algorithm. ›A station with a frame to transmit senses the medium. If the medium is idle, it waits to see if the medium remains idle for a time equal to IFS. If so, the station may transmit immediately. ›If the medium is busy (either because the station initially finds the medium busy or because the medium becomes busy during the IFS idle time), the station defers transmission and continues to monitor the medium until the current transmission is over.

18. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area MEDIUM access Control –Once the current transmission is over, the station delays another IFS. If the medium remains idle for this period, then the station backs off a random amount of time and again senses the medium. If the medium is still idle, the station may transmit. –During the back off time, if the medium becomes busy, the back off timer is halted and resumes when the medium becomes idle. –If the transmission is unsuccessful, which is determined by the absence of an acknowledgement, then it is assumed that a collision has occurred.

19. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area MEDIUM access Control ›Three types of IFS –SIFS (short IFS): The shortest IFS, used for all immediate response actions. Highest Priority. ›Receiver responds with an ACK frame after waiting only for an SIFS gap. ›After getting a (RTS) frame, The station to which this frame is addressed should immediately respond with a CTS frame. –PIFS (point coordination function IFS): A middle length IFS, used by the centralized controller in the PCF scheme when issuing polls.(Point Coordinator Function. Used to take precedence over normal contention traffic. –DIFS (distributed coordination function IFS): The longest IFS. Used for ordinary traffic

20. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area DCF Frame Exchange

21. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area DCF Frame exchange

22. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area DCF-Frame Exchange ›Network Allocation Vector –How do other stations defer sending their data if one station acquires access? ›Station sends an RTS frame, which includes the duration of time that it needs to occupy the channel. ›The stations that are affected by this transmission create a timer called a network allocation vector (NAV) that shows how much time must pass before these stations are allowed to check the channel for idleness. ›Each time a station accesses the system and sends an RTS frame, other stations start their NAV. ›Collision During Handshaking –What happens if there is a collision during the time when RTS or CTS control frames are in transition, often called the handshaking period? –Two or more stations may try to send RTS frames at the same time. These control frames may collide. –The sender assumes there has been a collision if it has not received a CTS frame from the receiver. The back-off strategy is employed, and the sender tries again.

23. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area DCF Frame Exchange ›Hidden-Station Problem –The solution to the hidden station problem is the use of the handshake frames (RTS and CTS). Figure shows that the RTS message from B reaches A, but not C. –B and C are within the range of A, the CTS message, which contains the duration of data transmission from B to A, reaches C. –Station C knows that some hidden station is using the channel and refrains from transmitting until that duration is over.

24. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Exposed station problem

25. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Point Coordination Function ›The point coordination function (PCF) is an optional access method that can be implemented in an infrastructure network (not in an ad hoc network). ›It is implemented on top of the DCF and is used mostly for time-sensitive transmission. ›PCF has a centralized, polling access method. The AP performs polling for stations that are capable of being polled. –Polling works with topologies in which one device is designated as a primary station and the other devices are secondary stations. –All data exchanges must be made through the primary device even when the ultimate destination is a secondary device. –The primary device controls the link; the secondary devices follow its instructions. –It is up to the primary device to determine which device is allowed to use the channel at a given time. –The primary device, therefore, is always the initiator of a session. –This method uses poll and select functions to prevent collisions. However, the drawback is if the primary station fails, the system goes down.

26. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Point Coordination Function ›The stations are polled one after another, sending any data they have to the AP. ›To give priority to PCF over DCF, another inter-frame space, PIFS, has been defined. PIFS (PCF IFS) is shorter than DIFS.

27. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Frame format ›The 802.11 standard defines three different classes of frames in the air –Data:Data frames are used for carrying data and control information. –Control:Control frames are used for accessing the channel and acknowledging frames. RTS,CTS and ACK –Management: used for the initial communication between stations and access points. ›Each of these has a header with a variety of fields used within the MAC sub-layer. ›There are some headers used by the physical layer but these mostly deal with the modulation techniques used.

28. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Frame format ›Frame control field is made up of 11 subfields. –Protocol: Data Control Management –Sub-Type Fields: RTS or CTS ›For a regular data frame (without quality of service), they are set to 10 and 0000 in binary. –The To DS and From DS bits are set to indicate whether the frame is going to or coming from the network connected to the APs, which is called the distribution system. –The More fragments bit means that more fragments will follow. –The Retry bit marks a retransmission of a frame sent earlier. –The Power management bit indicates that the sender is going into power-save mode. –The More data bit indicates that the sender has additional frames for the receiver. –The Protected Frame bit indicates that the frame body has been encrypted for security. –The Order bit tells the receiver that the higher layer expects the sequence of frames to arrive strictly in order.

29. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Frame format –The second field of the data frame, the Duration field, tells how long the frame and its acknowledgement will occupy the channel, measured in microseconds. ›It is present in all types of frames, including control frames, and is what stations use to manage the NAV mechanism. ›Data frames sent to or from an AP have three addresses, all in standard IEEE 802 format. –The first address is the receiver, and the second address is the transmitter. –The third address gives this distant endpoint. ›The Sequence field numbers frames so that duplicates can be detected. –Of the 16 bits available, 4 identify the fragment and 12 carry a number that is advanced with each new transmission. ›The Data field contains the payload, up to 2312 bytes.

30. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Frame format ›Last comes the Frame check sequence, which is the same 32-bit CRC. –Management frames have the same format as data frames, plus a format for the data portion that varies with the subtype (e.g., parameters in beacon frames). –Control frames are short. Like all frames, they have the Frame control, Duration, and Frame check sequence fields.

31. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Network Services ›The 802.11 standard defines the services for the –Clients –The Access Points –Network connecting them must be a conformant wireless LAN. › Association –Association service used by mobile stations to connect themselves to APs. –Used just after a station moves within radio range of the AP. –Station learns upon arrival through beacon frames or directly asking the APs ›Data rates supported ›Security arrangements ›Quality of service –The station sends a request to associate with the AP. –The AP may accept or reject the request.

32. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Network services ›Re-Association –Re-Association lets a station change its preferred AP. –This facility is useful for mobile stations moving from one AP to another AP in the same extended 802.11 LAN, like a handover in the cellular network. –If it is used correctly, no data will be lost as a consequence of the handover. ›Disassociation –Either the station or the AP may also disassociate, breaking their relationship. –A station should use this service before shutting down or leaving the network. The AP may use it before going down for maintenance. ›Authentication –Stations must also authenticate before they can send frames via the AP –Authentication depends upon the choice of security scheme. ›Open: Anyone is allowed to use it –WPA2 (Wireless Protected access) ›The AP can talk to an authentication server that has a username and password database to determine if the station is allowed to access the network.

33. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Network services –WEP (Wired Equivalent Privacy): Authentication with a pre-shared key happens before association. ›Distribution service at the AP –Once frames reach the AP, the distribution service determines how to route them. –If destination is local it can be directly distributed. ›Integration service handles any translation that is needed for a frame to be sent outside the 802.11 LAN, or to arrive from outside the 802.11 LAN. › Delivery services : –Data transmission is the main task of 802.11 so it provides a data delivery service. –This service lets stations transmit and receive using protocols (Protocols at the physical and Mac Layer etc) –Transmission over 802.11 is not guaranteed to be reliable. –Higher layers must deal with detecting and correcting errors.

34. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Network services ›Wireless is a broadcast signal so for confidentiality data must be encrypted. –Privacy service that manages the details of encryption and decryption. –Encryption algorithm for WPA2 based on AES (Advanced Encryption Standard) –The keys used for encryption are determined during the authentication procedure. › QOS traffic scheduling service. –Handle traffic with different priorities –Services to manage the use of the spectrum ›Transmit power control service information needed by stations to meet regulatory limits on transmit power that vary from region to region. ›The dynamic frequency selection service information to stations to avoid transmitting on frequencies in the 5-GHz band that are being used for radar in the proximity. ›

35. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area OFDM Basics

36. Slide title 44 pt Text and bullet level 1 minimum 24 pt Bullets level 2-5 minimum 20 pt Characters for Embedded font: !"#$%&'()*+,-./0123456789:; ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcde fghijklmnopqrstuvwxyz{|}~¡¢£¤¥¦§¨©ª«¬®¯°±²³´¶·¸¹º»¼½ÀÁÂÃÄÅ ÆÇÈËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùú ûüýþÿĀāĂăąĆćĊċČĎďĐđĒĖėĘęĚěĞğĠġĢģĪīĮįİıĶķĹĺĻļĽľŁłŃńŅņŇň ŌŐőŒœŔŕŖŗŘřŚśŞşŠšŢţŤťŪūŮůŰűŲųŴŵŶŷŸŹźŻżŽžƒȘșˆˇ˘˙˚˛˜˝Ẁ ẁẃẄẅỲỳ–— ‘’‚“”„†‡…‰‹›⁄€™ĀĀĂĂĄĄĆĆĊĊČČĎĎĐĐĒĒĖĖĘĘĚĚĞĞĠĠĢĢĪĪĮĮİĶĶĹĹĻĻĽĽŃ ŃŅŅŇŇŌŌŐŐŔŔŖŖŘŘŚŚŞŞŢŢŤŤŪŪŮŮŰŰŲŲŴŴŶŶŹŹŻŻȘș−≤≥fifl ΆΈΉΊΌΎΏΐΑΒΓΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΪΫΆΈΉΊΰαβγδεζηθικλνξορ ςΣΤΥΦΧΨΩΪΫΌΎΏ ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯАБ ВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯЁЂЃЄЅІЇЈЉЊЋЌЎЏѢѢѲ ѲѴѴҐҐә ǽ ẀẁẂẃẄẅỲỳ№ Do not add objects or text in the footer area Spread Spectrum basics ›Behrouz forouzan Section 6.2