IEEE 802.11 wireless lan(\u7121\u7dda\u5340\u57df\u7db2\u8def)<\/p>\n\n\n\n
\u4e3b\u8981\u7279\u6027
\u591a\u91cd\u50b3\u8f38\u901f\u7387,\u53ef\u7528\u4e0d\u540c\u7684\u50b3\u8f38\u901f\u7387, ex:0.5Mbps,1Mbps,2Mbps
\u50b3\u8f38\u548c\u63a5\u6536\u6703\u5728\u540c\u4e00\u500bchannel,\u56e0\u6b64\u7121\u6cd5\u540c\u6642\u9032\u884c,\u5c6c\u534a\u96d9\u5de5\u4f5c\u696d
\u57fa\u672c\u901a\u8a0a\u5354\u5b9a\u70baCSMA\/CA
\u5169\u7a2e\u50b3\u9001\u670d\u52d9\uff1aDCF,PCF
\u5141\u8a31ad-hoc\u548cinfrastructure\u7684\u7121\u7dda\u5340\u57df\u7db2\u8def\u540c\u6642\u4f7f\u7528\u540c\u4e00\u5957\u57fa\u672c\u64f7\u53d6\u5354\u5b9a\u3002
\u7121\u6cd5\u4fdd\u8a3c\u983b\u5bec,\u4e0d\u9069\u5408\u591a\u5a92\u9ad4\u50b3\u8f38
\u63d0\u4f9bAuthentication(\u8a8d\u8b49) \u53ca\u8cc7\u6599Privacy (\u4fdd\u5bc6) \u529f\u80fd
\u4f7f\u7528\u4e00\u7a2e\u9078\u9805\u914d\u5099,WEP(Wired Equivalent Privacy Algorithm,\u6709\u7dda\u7b49\u6548\u4fdd\u5bc6\u6f14\u7b97\u6cd5)\u7dad\u6301\u5b89\u5168<\/p>\n\n\n\n
\u8207\u50b3\u7d71\u6709\u7dda\u4e0d\u540c\u7684\u7279\u6027:
1\u56e0\u53ef\u79fb\u52d5,Destination Address(\u76ee\u7684\u4f4d\u5740)\u901a\u5e38\u4e0d\u7b49\u65bcDestination Location(\u76ee\u7684\u4f4d\u7f6e)
2\u50b3\u8f38\u5a92\u4ecb\u6703\u5f71\u56ae\u6574\u4f53\u7db2\u8def\u7684\u8a2d\u8a08\uff1a\u56e0\u5be6\u4f53\u5c64\u8a2d\u8a08\u5927\u4e0d\u540c
3\u8981\u80fd\u8655\u7406\u6703\u79fb\u52d5\u7684\u5de5\u4f5c\u7ad9
4\u548c\u5176\u5b83IEEE 802\u7db2\u8def\u5c64\u9593\u7684\u95dc\u4fc2\u4e0d\u540c<\/p>\n\n\n\n
\u5f71\u97ffwireless\u6700\u5e38\u898b\u7684\u539f\u56e0<\/strong> \u5e38\u898b802\u7121\u7dda\u7db2\u8def\u5982\u4e0b: \u5176\u4ed6802.11\u6a19\u6e96\u5982\u4e0b: ps: ps: …………………………………………………………… <\/p>\n\n\n\n \u4f7f\u7528\u7121\u7dda\u5a92\u9ad4\u8981\u53bb\u5075\u6e2c\u7db2\u8def\u4e2d\u7684\u78b0\u649e\u73fe\u8c61\u662f\u6975\u70ba\u56f0\u96e3\u7684\u3002\u56e0\u6b64\u63a1\u53d6\u907f\u514d\u78b0\u649e\u7b56\u7565\uff0c\u4f86\u907f\u514d\u5a92\u9ad4\u4e2d\u767c\u751f\u78b0\u649e\u7684\u60c5\u5f62 … <\/p>\n\n\n\n IEEE 802.11MAC\u8a0a\u6846\u683c\u5f0f:<\/strong> Frame Control\u6b04\u4f4d 2byte<\/strong> … <\/p>\n\n\n\n media access control(\u5a92\u9ad4\u5b58\u53d6\u63a7\u5236)\u7684\u64f7\u53d6\u65b9\u6cd5\u6709: ……………………………………………………………<\/p>\n\n\n\n IEEE 802.11\u5b9a\u7fa9\u7684\u8edf\u9ad4\u67b6\u69cb<\/strong><\/p>\n\n\n\n Station Services(\u7ad9\u9ede\u670d\u52d9):<\/strong> Distribution System Services(\u5206\u914d\u7cfb\u7d71\u670d\u52d9):<\/strong> IEEE 802.11\u5b9a\u7fa9\u7684\u786c\u4f53\u67b6\u69cb \u786c\u9ad4\u67b6\u69cb\u7531\u4e0b\u5217\u5143\u4ef6\u6240\u7d44\u6210<\/strong> \u7121\u7dda\u7db2\u8def\u5be6\u9ad4\u5c64\u7279\u9ede<\/strong> ps: IEEE 802.11 wireless lan(\u7121\u7dda\u5340\u57df\u7db2 …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[26],"tags":[],"class_list":["post-803","post","type-post","status-publish","format-standard","hentry","category-osi-layer2"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/803","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/comments?post=803"}],"version-history":[{"count":0,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/803\/revisions"}],"wp:attachment":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/media?parent=803"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/categories?post=803"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/tags?post=803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
cordless phones(\u5ba4\u5167\u7121\u7dda\u96fb\u8a71)
metal file cabinets(\u91d1\u5c6c\u6ac3)
antenna type or direction(\u5929\u7dda\u65b9\u5411)
microwave oven(\u5fae\u6ce2\u7210)<\/p>\n\n\n\n
802.11:1997\u5e74
\u3000\u5be6\u9ad4\u5c64:\u7d05\u5916\u7dda,fhss,dsss
\u3000\u901f\u7387:1mbps(\u63a1\u7528dbpsk),2mbps(\u63a1\u7528dqpsk)
\u3000\u983b\u7387:2.4ghz
802.11a:1999\u5e74
\u3000\u5be6\u9ad4\u5c64:ofdm
\u3000\u983b\u7387:5ghz
\u3000\u901f\u7387:54,48,36,24,18,12,9,6mbps,\u82e5\u7528rate doubling\u5c08\u5229\u6280\u8853\u53ef\u9054108mbps
\u3000\u8ddd\u96e2:\u8ddd\u96e2\u77ed,\u5ba4\u516730\u5c3a,\u7d0475feet,\u82e5\u4f7f\u7528\u6700\u4f4e6mb\u50b3\u8f38\uff0c\u8ddd\u96e2\u53ef\u9577\u9054175feet
\u3000non-overlapping channel\u6578\u91cf:\u5317\u7f8e12,\u6b50\u6d3219,\u65e5\u672c8
802.11b:1999\u5e74
\u3000\u5be6\u9ad4\u5c64:hr-dsss
\u3000\u983b\u7387:2.4ghz(2.4GHz-2.485GHz)
\u3000\u901f\u7387:11mbps,\u4f9d\u74b0\u5883\u54c1\u8cea\u53ef\u81ea\u52d5\u8abf\u6574\u62105.5\/2\/1Mbps\uff0c\u6700\u9ad8\u53ef\u64f4\u5145\u523022Mbps
\u3000\u8ddd\u96e2:\u8ddd\u96e2\u9060(a\u76847\u500d),\u5ba4\u516730\u5c3a,\u7d04150feet,\u82e5\u4f7f\u7528\u6700\u4f4e1mb\u50b3\u8f38\uff0c\u8ddd\u96e2\u53ef\u9577\u9054350feet
\u3000channel\u6578\u91cf:\u5317\u7f8e11,\u6b50\u6d3213,\u65e5\u672c14,\u800cnon-overlapping channel\u53ea\u63d0\u4f9b3\u500b
802.11g:
\u3000\u5be6\u9ad4\u5c64:ofdm
\u3000\u983b\u7387:2.4ghz,\u8207802.11b\u76f8\u5bb9
\u3000\u901f\u7387:54mbps,\u7406\u8ad6\u4e0a\u53ef\u9054108,125mbps
\u3000\u8ddd\u96e2:\u8ddd\u96e2\u6bd4b\u77ed\u6bd4a\u9060,\u5ba4\u516730\u5c3a\u5ba4\u5916100\u5c3a,\u7d04100feet,\u82e5\u4f7f\u7528\u6700\u4f4e6mb\u50b3\u8f38,\u8ddd\u96e2\u53ef\u9577\u9054300feet
\u3000channel\u6578\u91cf:\u5317\u7f8e11,\u6b50\u6d3213,\u65e5\u672c14,\u800cnon-overlapping channel:\u53ea\u63d0\u4f9b3\u500b
802.11n:
\u3000\u983b\u7387:5\/2.4ghz
\u3000\u901f\u7387:540,300,240,108mbps
\u3000\u8ddd\u96e2:\u5ba4\u516750\u5c3a,\u5ba4\u5916125\u5c3a,
\u3000\u5c0e\u5165mimo(mutliple input multiple output,\u591a\u91cd\u8f38\u5165\u8f38\u51fa)
\u3000\u53ef\u6eff\u8db3\u9ad8\u89e3\u6790\u5ea6\u8996\u8a0a\u50b3\u8f38\u3001\u5bb6\u5ead\u5f71\u9662\u7b49\u5168\u65b0\u61c9\u7528\u5c0d\u6578\u64da\u901f\u7387\u7684\u66f4\u9ad8\u7684\u8981\u6c42
802.16(WiMAX,\u5bec\u983b\u7121\u7dda\u7db2\u8def),
\u3000\u5168\u96d9\u5de5,\u975e\u79fb\u52d5\u6027,\u9060\u8ddd\u96e2,10-66GHZ\u983b\u7387\u904b\u4f5c,\u9069\u5408\u505aMAN
\u3000\u5c6c\u65bclast mile\u6280\u8853
\u3000\u50b3\u8f38\u8a0a\u6846\u5206\u70badown-link subframe\u548cuplink subframe
\u6709\u63d0\u4f9bscheduling\u67b6\u69cb,\u4e14\u53ef\u9078\u64c7\u4e0d\u540c\u7684scheduling\u6f14\u7b97\u6cd5 \u3000\u3000
802.15(PAN,personal area network)\uff1a
802.15.1(\u85cd\u82bd),dsss2.4ghz,\u6700\u591a\u53ef\u63a5\u4e03\u500b\u8a2d\u5099
ps:5ghz\u7121\u6cd5\u76f4\u63a5\u82072.4ghz\u6e9d\u901a
ps:802.11a\/b\/g\u4e3b\u8981\u5728\u8edf\u9ad4\u4e0a\u7a81\u7834,802.11n\u5247\u662f\u5728\u786c\u9ad4\u4e0a\u7a81\u7834<\/p>\n\n\n\n
802.11d:\u5b9a\u7fa9\u4e86\u4e00\u4e9b\u7269\u7406\u5c64\u65b9\u9762\u7684\u8981\u6c42(\u8af8\u5982\u4fe1\u9053\u5316\u3001\u8df3\u983b\u6a21\u5f0f\u7b49)\u4ee5\u9069\u61c9802.11\u8a2d\u5099\u5728\u9019\u4e9b\u570b\u5bb6\u7121\u7dda\u96fb\u7ba1\u5236\u4e0a\u7684\u7279\u6b8a\u8981\u6c42
802.11e:\u8a02\u51fa\u52a0\u5bc6\u3001\u8a8d\u8b49\uff0c\u4ee5\u53caQoS\u7684\u5171\u901a\u898f\u683c
802.11c:\u5b9a\u7fa9WLAN AP\u4e4bBridge\u529f\u80fd\u3002
802.11f:\u70ba\u589e\u9032\u6f2b\u904a\u529f\u80fd\u5b9a\u7fa9AP\u8207AP\u4e4b\u901a\u8a0a\uff0c\u8b93\u4f7f\u7528\u8005\u80fd\u8de8AP\u800c\u505a\u6f2b\u904a\u3002
802.11i:\u70ba\u88dc\u8db3\u8106\u5f31\u7684WEP,\u5b9a\u7fa9WPA2,\u70baWLAN\u7684\u5b89\u5168\u6a19\u6e96\u3002
802.11j:\u4fc3\u9032802.11a\u53caHyperLAN2\u4e4b\u4e26\u5b58\u3002
802.11k:\u70ba\u65b9\u4fbfWLAN\u7db2\u8def\u7ba1\u7406\u800c\u8a2d
802.11m:\u7528\u65bc\u5c0d802.11\u5404\u6a19\u6e96\u9032\u884c\u7dad\u8b77
802.11p:\u4e3b\u8981\u61c9\u7528\u65bc\u667a\u6167\u4ea4\u901a\u9818\u57df\u7684\u7121\u7dda\u9023\u63a5
802.11r:\u5c0d802.11\u7684\u5feb\u901f\u6f2b\u904a\u9032\u884c\u4e86\u6539\u9032\uff0c\u5c07\u80fd\u4fdd\u8b49\u7126\u9ede\u9593\u9023\u63a5\u7684\u7121\u7e2b\u6027
802.11s:\u5c0d802.11\u589e\u52a0\u4e86mesh\u7db2\u8def\u7684\u652f\u63f4
802.11h:\u70ba\u7b26\u5408\u5176\u4ed6\u570b\u5bb6\u7684DFS (Dynamic Frequency Selection)\u53caTPC (Transmit Power Control)\u6a19\u6e96\u3002\u70ba\u4e86\u907f\u514d\u983b\u5e36\u5e72\u64fe\u8207\u885d\u7a81\uff08\u6b50\u6d32\u570b\u5bb6\uff09\u3002<\/p>\n\n\n\n
Wi-Fi(Wireless fidelity)
\u4e00\u500b\u7121\u7dda\u7db2\u8def\u901a\u4fe1\u7684\u5de5\u696d\u6a19\u6e96
WECA\u806f\u76df\u7528\u4f86\u57f7\u884c\u5404\u5bb6\u7522\u54c1\u76f8\u5bb9\u6027\u8a8d\u8b49,\u4e00\u4f46\u901a\u904ewi-fi\u8a8d\u8b49\u7684\u7522\u54c1\u8868\u793a\u8a2d\u5099\u5f7c\u6b64\u4e4b\u9593\u53ef\u4ee5\u4e92\u901a<\/p>\n\n\n\n
\u6839\u64daNCC(2014)\u7684\u8cc7\u6599\uff0c\u53f0\u7063\u958b\u653e\u4e0b\u52173\u500b5GHz\u983b\u6bb5\uff1a
5250\uff5e5350MHz<\/strong>
(CH52 5260MHz\u3001CH56 5280MHz\u3001CH60 5300MHz\u3001CH64 5320MHz)
\u53ea\u80fd\u5728\u5ba4\u5167\u4f7f\u7528
5470\uff5e5725MHz<\/strong>
(CH100 5500MHz\u3001CH104 5520MHz\u3001CH108 5540MHz\u3001CH112 5560MHz\u3001CH116 5580MHz\u3001CH120 5600MHz\u3001CH124 5620MHz\u3001CH128 5640MHz\u3001CH132 5660MHz\u3001CH136 5680MHz\u3001CH140 5700MHz)
\u8a72\u983b\u6bb5\u4e3b\u8981\u88ab\u8ecd\u65b9\u548c\u6c23\u8c61\u7528\u96f7\u9054\u4f7f\u7528\uff0c\u82e5\u8981\u4f7f\u7528\u8a72\u983b\u6bb5\uff0c\u53ef\u80fd\u9808DFS\u548cTPC\uff0c\u7576\u88dd\u7f6e\u611f\u6e2c\u5230\u76ee\u524d\u983b\u7387\u6709\u5176\u5b83\u4eba\u5728\u4f7f\u7528\u6642\uff0c\u5fc5\u9808\u80fd\u5920\u8df3\u958b\u6539\u63a1\u5176\u5b83\u983b\u7387
5725\uff5e5825MHz<\/strong>
(CH149 5745MHz\u3001CH153 5765MHz\u3001CH157 5785MHz\u3001CH161 5805MHz\u3001CH165 5825MHz)
\u5927\u90e8\u4efd\u8a2d\u5099\u90fd\u652f\u63f4\u9019\u983b\u7387\u5340\u9593,\u4f7f\u7528\u4e0a\u8f03\u6c92\u6709\u554f\u984c
refer
http:\/\/www.techbang.com\/posts\/13944-wi-fi-5ghz-do-you-support<\/p>\n\n\n\n
\u4e3b\u8981\u67093\u5927\u968e\u6bb5:
1\u4f9dRBT\u6c7a\u5b9a\u662f\u5426\u8981\u9001RTS<\/strong>
\u7576\u7121\u7dda\u7db2\u8def\u5361\u8981\u767c\u51fa\u8cc7\u6599\u6642\uff0c\u6839\u64da\u4ee5\u4e0b\u5169\u60c5\u6cc1\u6c7a\u5b9a\u52d5\u4f5c
\u3000\u82e5\u901a\u9053\u9592\u7f6e:\u7b49\u5f85DIFS(distributed inter frame space,\u5206\u6563\u5f0f\u8a0a\u6846\u9593\u9694)\u7684\u6642\u9593\u5f8c\u5728\u5230\u6b65\u9a5f2
\u3000\u82e5\u901a\u9053\u975e\u9592\u7f6e:\u7522\u751f\u4e00\u500bRandom Backoff Time(\u96a8\u6a5f\u7684\u5ef6\u9072\u6642\u9593)\u3002\u5728\u5ef6\u9072\u6642\u9593\u88e1\uff0c\u7121\u7dda\u7db2\u8def\u82e5\u767c\u73fe\u983b\u9053\u5fd9\u788c\u7684\u8a71\uff0c\u5247\u51cd\u7d50\u5ef6\u9072\u6642\u9593\u7684\u8a08\u7b97\u7684\u5de5\u4f5c; \u76f4\u5230\u78ba\u8a8d\u983b\u9053\u662f\u7a7a\u9592\u7684\u518d\u7e7c\u7e8c\u8a08\u7b97\u3002\u76f4\u5230\u5ef6\u9072\u6642\u9593\u4e00\u5230\uff0c\u518d\u5230\u6b65\u9a5f2\u3002
2\u9001\u51faRTS\u53d6\u5f97\u767c\u9001\u8cc7\u6599\u7684\u6b0a\u5229<\/strong>
\u7db2\u5361\u5728\u767c\u51fa\u8cc7\u6599\u524d\uff0c\u5148\u767c\u51faRTS(Request To Send)\u7684\u901a\u77e5\u8a0a\u865f\uff0c
\u53ef\u80fd\u6703\u6709\u5169\u60c5\u6cc1
\u30001\u591a\u500b\u767c\u9001\u7aef\u540c\u6642\u767c\u9001RTS,\u6240\u4ee5\u7522\u751f\u78b0\u649e,\u6240\u6709\u767c\u9001\u7aef\u56de\u5230\u7b2c1\u6b65
\u30002\u76ee\u7684\u7aef\u6536\u5230\u5176\u4e2d\u4e00\u500b\u767c\u9001\u7aef\u7684RTS\u8a0a\u865f\u5f8c,\u56de\u61c9CTS(Clear To Send)\u8a0a\u865f\u3002
3\u6536\u5230CTS\u5f8c\u958b\u59cb\u9001\u51fa\u8cc7\u6599<\/strong>
\u767c\u9001\u7aef\u6536\u5230CTS\u8a0a\u865f\u5f8c\u624d\u628a\u8cc7\u6599\u767c\u9001\u51fa\u53bb\u3002
\u5176\u4ed6\u8981\u50b3\u9001\u8cc7\u6599\u7684\u7121\u7dda\u7db2\u8def\u7bc0\u9ede.\u5982\u5075\u6e2c\u5230\u5a92\u9ad4\u4e2d\u5b58\u6709RTS\u6216CTS\u8a0a\u865f\u6642,\u5247\u6703\u56e0\u70ba\u8655\u65bc\u5ef6\u9072\u6642\u9593\u51cd\u7d50\u7684\u968e\u6bb5,\u56e0\u6b64\u4e0d\u6703\u5728\u6b64\u6642\u50b3\u9001\u8cc7\u6599
\u842c\u4e00\u50b3\u9001\u8cc7\u6599\u7684\u7121\u7dda\u7db2\u8def\u7bc0\u9ede\u6b64\u6642\u6b63\u5de7\u5230\u9054\u5ef6\u9072\u6642\u9593\u800c\u767c\u51faRTS\uff0c\u4fbf\u6703\u9020\u6210\u773e\u591aRTS\/CTS\u8a0a\u865f\u5f7c\u6b64\u767c\u751f\u78b0\u649e\uff0c\u5c0d\u65bc\u50b3\u9001\u8cc7\u6599\u7684\u8a0a\u865f\u4f86\u8aaa\uff0c\u4e26\u4e0d\u6703\u9020\u6210\u4efb\u4f55\u5f71\u97ff
ps:
\u8cc7\u6599\u50b3\u5b8c\u5f8c,\u63a5\u6536\u7aef\u5728SIFS(shart inter frame space,\u77ed\u66ab\u8a0a\u6846\u9593\u9694)\u7684\u6642\u9593\u5f8c\u56de\u50b3\u78ba\u8a8d\u8a0a\u6846,\u544a\u8a34\u50b3\u9001\u7aef\u8cc7\u6599\u6b63\u78ba\u63a5\u6536
\u82e5\u50b3\u9001\u7aef\u90fd\u6c92\u6536\u5230\u78ba\u8a8d\u8a0a\u6846,\u5247\u6703\u5728\u91cd\u9001\u4e00\u6b21\u8cc7\u6599
ps:
RTS\/CTS\u6a5f\u5236\u53ef\u89e3\u6c7ahidden terminal problem<\/p>\n\n\n\n
Header(\u8868\u982d) 30byte,\u5982\u4e0b:
Frame Control (2byte)\uff1a\u670911\u500b\u5b50\u6b04\u4f4d
Duration\/ID (2byte)\uff1a\u8a0a\u6846\u56de\u61c9\u5c07\u4f54\u64da\u983b\u9053\u7684\u6642\u9593\u9577\u5ea6
Address 1 (6byte) :ap mac addr
Address 2 (6byte) :src host addr
Address 3 (6byte) :dst addr
Sequence Control (2byte):\u53ef\u7528\u4f86\u5207\u5272\u7247\u6bb5\u6a19\u4e0a\u865f\u78bc
Address 4 (6byte) :used only in ad hoc mode
\u8cc7\u6599 (0-2312byte)
\u932f\u8aa4\u6aa2\u67e5\u78bc(4byte):crc-32\u6280\u8853<\/p>\n\n\n\n
Protocol Version 2bit: 802.11 \u6a19\u6e96\u7248\u672c
Type 2bit: \u8a0a\u6846\u578b\u614b (Data \u8a0a\u6846, Control \u8a0a\u6846, Management \u8a0a\u6846)
Subtype \u6b21\u578b\u614b 4bit rts,cts
To DS 1bit: \u503c\u70ba1\u8868Data\u8a0a\u6846\u8981\u50b3\u9001\u7d66\u5206\u6563\u5f0f\u7cfb\u7d71
From DS 1bit: \u503c\u70ba1\u8868Data \u8a0a\u6846\u7531\u5206\u6563\u5f0f\u7cfb\u7d71\u50b3\u9001\u4e0b\u4f86
More Fragments 1bit:\u503c\u70ba1\u8868\u5de5\u4f5c\u7ad9\u5c1a\u6709\u5176\u4ed6\u7247\u6bb5(Fragments)\u5f85\u50b3\u9001
Retry 1bit:\u503c\u70ba1\u8868Data\u8a0a\u6846\uff08\u6216Management\u8a0a\u6846\uff09\u70ba\u91cd\u9001\u4e4b\u8a0a\u6846
Power Management 1bit:\u503c\u70ba1\u8868\u6b64\u5de5\u4f5c\u7ad9\u8655\u65bc\u7701\u96fb\u6a21\u5f0f,ap\u9700\u70ba0
More Data 1bit:\u503c\u70ba1\u8868\u81f3\u5c11\u9084\u6709\u4e00\u500b MSDU \u5f85\u8f49\u9001(AP\u901a\u77e5\u7701\u96fb\u6a21\u5f0f\u5de5\u4f5c\u7ad9)
WEP 1bit: \u503c\u70ba1\u8868Data\u8a0a\u6846\uff08\u6216Management\u8a0a\u6846\uff09\u6240\u5e36\u8cc7\u6599\u7d93\u904eWEP\u6f14\u7b97\u6cd5\u8655\u7406
Order 1bit: \u503c\u70ba1\u8868Data\u8a0a\u6846\u7531\u56b4\u683c\u4f9d\u5e8f\u670d\u52d9\u7b49\u7d1a(Strictly-Ordered service class)\u4f86\u50b3\u9001
ps:to DS,from DS\u7684\u56db\u7a2e\u7d44\u5408
To DS=0 From DS=0 \u8868Data\u8a0a\u6846\u7531\u4e00\u500b\u5de5\u4f5c\u7ad9\u50b3\u9001\u7d66\u53e6\u500bBSS\u4e2d\u7684\u5de5\u4f5c\u7ad9
To DS=1 From DS=1 \u7531\u4e00\u500bAP \u50b3\u7d66\u53e6\u5916\u4e00\u500bAP \u7684WDS\u8a0a\u6846<\/p>\n\n\n\n
DCF<\/strong>(Distributed Coordination Function, \u5206\u6563\u5354\u8abf\u5f0f\u529f\u80fd)<\/strong>
\u662fMAC\u57fa\u672c\u64f7\u53d6\u65b9\u6cd5,\u7528CSMA\/CA,
\u975e\u540c\u6b65\u50b3\u8f38,contention(\u7af6\u722d)\u65b9\u6cd5
DCF\u53ef\u7528\u5728Ad Hoc\u548cInfrastructure\u7684\u7121\u7dda\u5340\u57df\u7db2\u8def\u67b6\u69cb\u4e2d,\u9069\u5408\u50b3\u975e\u5373\u6642\u8cc7\u8a0a
PCF<\/strong>(Point Coordination Function, \u96c6\u4e2d\u5354\u8abf\u5f0f\u529f\u80fd)<\/strong>
\u8b93\u5de5\u4f5c\u7ad9\u9001\u6536\u5177time bounded(\u6642\u9650\u6027)\u7684\u8cc7\u6599,\u5c6c\u65bccontention free(\u514d\u7af6\u722d)\u65b9\u6cd5,\u8a0a\u6846\u4e0d\u6703\u78b0\u649e
Point Coordinator(\u7db2\u8def\u5354\u8abf\u8005)\u7528polling(\u8f2a\u8a62)\u6a5f\u5236,\u53ef\u63d0\u4f9b\u4fdd\u8a3c\u50b3\u9001\u5ef6\u9072\u670d\u52d9
PCF\u662f\u900f\u904eDCF\u4f86\u5b8c\u6210\u7684
PCF\u53ea\u7528\u5728infrastructure mode\u4e2d
ps:Coordination Function(\u5354\u8abf\u5f0f\u529f\u80fd):\u6c7a\u5b9a\u4f55\u6642\u90a3\u500b\u5de5\u4f5c\u7ad9\u80fd\u958b\u59cb\u9001\u6536\u8cc7\u6599\u7684\u6a5f\u5236
ps:\u9032\u884c\u4e00\u6bb5\u6642\u9593\u7684PCF\uff0c\u518d\u8ddf\u8457\u9032\u884c\u4e00\u6bb5\u6642\u9593\u7684DCF,Superframe (\u8d85\u7d1a\u8a0a\u6846)<\/p>\n\n\n\n
Authentication(\u8a8d\u8b49\u670d\u52d9):\u300c\u76e4\u554f\/\u56de\u61c9\u300d(Challenge\/Response\uff0cC\/R)\u8eab\u4efd\u78ba\u8a8d\u65b9\u6cd5
1Assertion of Identity(\u8072\u660e\u8eab\u4efd)
2Challenge of Assertion(\u76e4\u554f\u8072\u660e)
3Response to Challenge(\u56de\u61c9\u76e4\u554f)
Deauthentication(\u7d50\u675f\u8a8d\u8b58)
Privacy(\u96b1\u5bc6\u6027\u670d\u52d9):\u5c07\u8cc7\u6599\u505a\u52a0\u5bc6\u8207\u89e3\u5bc6(\u7528privacy algorithm\u96b1\u5bc6\u6027\u670d\u52d9\u6f14\u7b97\u6cd5)
MSDU delivery(MAC \u6578\u64da\u50b3\u8f38)<\/strong><\/p>\n\n\n\n
Association(\u806f\u7d50\u670d\u52d9):\u5728\u5de5\u4f5c\u7ad9\u548c\u64f7\u53d6\u9ede\u9593\u5efa\u7acb\u901a\u8a0a\u9023\u7dda
Disassociation(\u53d6\u6d88\u806f\u7d50\u670d\u52d9):\u53d6\u6d88\u4e00\u500b\u806f\u7d50(\u4efb\u4e00\u65b9\u53ef\u555f\u52d5)
Distribution(\u5206\u9001\u670d\u52d9):\u6c7a\u5b9a\u8a72\u8a0a\u6846\u9001\u5f80\u90a3\u500b\u8f38\u51fa\u64f7\u53d6\u9ede
Integration(\u6574\u5408\u670d\u52d9):\u5c07\u8a0a\u6846\u5f9e\u5206\u6563\u7cfb\u7d71\u8f49\u9001\u5230portal(\u9023\u5340\u57df\u7db2\u8def\u65f3\u5a92\u4ecb\uff09,\u5c07\u4e0d\u540c\u4f4d\u5740\u7a7a\u9593\u8f49\u63db
Reassociation(\u91cd\u806f\u7d50\u670d\u52d9):\u5de5\u4f5c\u7ad9\u7684\u806f\u7d50\u5f9e\u4e00\u500b\u64f7\u53d6\u9ede\u8f49\u79fb\u5230\u53e6\u4e00\u500b\u64f7\u53d6\u9ede\uff08\u5148\u53d6\u6d88\u820a\u806f\u7d50,\u5728\u806f\u7d50\u65b0\u7684\uff09<\/p>\n\n\n\n
\u4f9d\u662f\u5426\u4f7f\u7528ap\u5206\u70ba:
Infrastructure Wireless LAN<\/strong>(\u6709\u57fa\u790e\u67b6\u69cb)<\/strong>
\u4e00\u500b\u73fe\u5b58\u7684wired distribution system(\u6709\u7dda\u7db2\u8def\u5206\u6563\u5f0f\u7cfb\u7d71)
access points(\u5b58\u5728\u64f7\u53d6\u9ede)\u5c07\u4e00\u500b\u6216\u591a\u500b\u7684\u7121\u7dda\u5340\u57df\u7db2\u8def\u548c\u73fe\u5b58\u7684\u6709\u7dda\u7db2\u8def\u5206\u6563\u7cfb\u7d71\u76f8\u9023\u7d50\uff0c\u63d0\u4f9b\u67d0\u7121\u7dda\u5340\u7db2\u4e2d\u7684\u5de5\u4f5c\u7ad9\uff0c\u80fd\u548c\u8f03\u9060\u8ddd\u96e2\u7684\u53e6\u4e00\u500b\u7121\u7dda\u5340\u7db2\u7684\u5de5\u4f5c\u7ad9\u901a\u8a0a\uff0c\u53e6\u4e00\u65b9\u9762\u4e5f\u4fc3\u4f7f\u7121\u7dda\u5340\u57df\u7db2\u8def\u4e2d\u7684\u5de5\u4f5c\u7ad9\uff0c\u80fd\u64f7\u53d6\u6709\u7dda\u5206\u6563\u5f0f\u7cfb\u7d71\u4e2d\u7684\u7db2\u8def\u8cc7\u6e90
\u9019\u4e00\u985e\u578b\u7684\u7121\u7dda\u7db2\u8def\u901a\u8a0a\u7bc4\u570d\uff0c\u901a\u5e38\u662f\u4ee5\u540c\u4e00\u68df\u5efa\u7bc9\u7269\u51fa\u73fe\uff0c\u4f8b\u5982\uff0c\u5546\u5e97\u3001 \u91ab\u9662\u3001\u6216\u662f\u540c\u4e00\u68df\u6a13\u5c64
\u6bd4ad hoc\u67b6\u69cb\u591a\u4e86ap\u548cds
\u61c9\u7528
single hop ex:wifi,wimax,…\u7b49
multile hops ex:mesh net
Ad Hoc Wireless LAN<\/strong>(\u7121\u57fa\u790e\u67b6\u69cb)<\/strong>
\u4e5f\u7a31\u96a8\u610f\u5f0f\u7db2\u8def,\u76f8\u7576\u65bcpeer-to-peer(\u5c0d\u7b49\u5f0f)\u9023\u63a5\u7db2\u8def
\u4e5f\u7a31\u70baIBSS(independent basic service set,\u7368\u7acb\u7684\u57fa\u790e\u670d\u52d9)\u7db2\u8def
\u63d0\u4f9b\u4e0d\u9650\u91cf\u7684\u7528\u6236\uff0c\u80fd\u5373\u6642\u67b6\u8a2d\u8d77\u7121\u7dda\u901a\u4fe1\u7db2\u8def
\u4efb\u4e8c\u500b\u7528\u6236\u9593\u53ef\u76f4\u63a5\u901a\u8a0a\uff0c\u5728\u6703\u8b70\u5ba4\u88e1\u7d93\u5e38\u7528\u5f97\u4e0a
\u61c9\u7528
single hop ex:bluetooth
multple hop ex:manet,vanet(Vehicular ad-hoc network) <\/p>\n\n\n\n
Station(\u5de5\u4f5c\u7ad9):\u4efb\u4f55\u8a2d\u5099\u53ea\u8981\u64c1\u6709IEEE 802.11\u7684MAC\u5c64\u548cPHY\u5c64\u7684\u4ecb\u9762\uff0c\u5c31\u53ef\u7a31\u70ba\u4e00\u500b\u5de5\u4f5c\u7ad9\u3002
BSA (Basic Service Area):\u6709\u57fa\u790e\u67b6\u69cb\u7684\u6bcf\u500b\u5e7e\u4f55\u5efa\u69cb\u5340\u584a,\u70ba\u57fa\u672c\u670d\u52d9\u5340\u57df
BSS (Basic Service Set):\u57fa\u672c\u670d\u52d9\u5340\u4e2d\u6240\u6709\u5de5\u4f5c\u7ad9\u7684\u96c6\u5408,\u901a\u5e38\u662f\u4e00\u500bap\u7684\u7bc4\u570d,\u6216ad hoc\u67b6\u69cb\u7684\u96fb\u8166\u7bc4\u570d
ESS(extend service set):\u5169\u500b\u4ee5\u4e0a\u7684BSS\u96c6\u5408
DS(Distribute System,\u5206\u6563\u5f0f\u7cfb\u7d71):\u901a\u5e38\u7531\u6709\u7dda\u7db2\u69cb\u6210\uff0c\u53ef\u9023\u7d50\u6578\u500bBSS
Portal(\u57e0\u63a5\u5668):ap\u8207\u6709\u7dda\u5340\u7db2\u9023\u7d50\u7684\u9023\u7d50\u8a2d\u5099
ps:BSSID\u901a\u5e38\u6307\u7684\u662fBSS(AP)\u7684MAC…………..<\/p>\n\n\n\n
\u9ede\u548c\u9ede\u9593\u7684\u9023\u7d50\u7bc4\u570d\u6709\u9650
\u4f7f\u7528\u9700\u8981\u5171\u4eab\u7684\u50b3\u8f38\u5a92\u4ecb
\u8a0a\u865f\u672a\u4fdd\u8b77\u6613\u53d7\u5e72\u64fe
\u6709\u52d5\u614b\u7684\u7db2\u8def\u62d3\u6a38\u7d50\u69cb
802.11\u5be6\u4f53\u5c64<\/strong>
\u7d05\u5916\u7dda<\/strong>
1mbps,2mbps,\u7528\u683c\u96f7\u78bc,\u77ed\u8ddd\u7121\u7dda\u96fb\u6280\u8853
FHSS(Frequency Hopping Spread Spectrum,\u8df3\u983b\u5c55\u983b)<\/strong>
\u6709\u8f03\u4f73\u7684\u4fdd\u5bc6\u6027\uff0c\u514b\u670d\u591a\u91cd\u8def\u5f91\u7684\u554f\u984c(\u66f4\u591a\u7684\u983b\u905375\u500b,DSSS\u53ea\u670911\u500b)
\u50b3\u8f38\u901f\u5ea6\u8f03\u6162,\u67092mbps\u7684\u8cc7\u6599\u50b3\u8f38\u901f\u7387\u9650\u5236
DSSS(Direct Sequence Spread Spectrum,\u76f4\u63a5\u5e8f\u5217\u5c55\u983b)<\/strong>
\u8f03\u898f\u5247\u6027\u7684\u65b9\u5f0f\uff0c\u6210\u5e8f\u5217\u5f0f\u5c55\u958b\u78bc\u4f86\u50b3\u9001\u6280\u8853\u3002
\u53ef\u63d0\u4f9b\u9ad8\u50b3\u8f38\u7387\u8207\u5927\u7bc4\u570d\u7684\u5b58\u53d6,\u6700\u9ad8\u53ef\u652f\u63f4\u523011mbps
OFDM(Orthoogonal Frequency Division Multiplexing,\u6b63\u4ea4\u5206\u983b\u591a\u5de5)<\/strong>
52\u7a2e\u4e0d\u540c\u983b\u7387,48\u7a2e\u7528\u65bc\u8cc7\u6599,4\u7a2e\u7528\u65bc\u540c\u6b65\u5316
802.11n\/g\u6709\u4f7f\u7528\u6280\u8853
HR-DSSS(high rate direct sequence spread spectrum,\u9ad8\u901f\u76f4\u63a5\u5e8f\u5217\u5c55\u983b)<\/strong>
\u53e6\u4e00\u7a2e\u5c55\u983b\u6280\u8853
ss(spread spectrum,\u5c55\u983b)\u6280\u8853<\/strong>
1940\u6240\u958b\u767c\u7684\u8abf\u8b8a\u6280\u8853,\u53ef\u5728\u7121\u7dda\u96fb\u983b\u7387\u4e0a\u5c55\u958b\u50b3\u8f38\u7684\u8a0a\u865f
\u5229\u7528\u72a0\u7272\u4e00\u4e9b\u983b\u7387\u7684\u65b9\u6cd5\u4f86\u9054\u5230\u8f03\u4f73\u7684signal-to-noise(\u8a0a\u865f\u8207\u8a0a\u96dc\u6bd4)
\u6b64\u6280\u8853\u4e0d\u6613\u53d7\u7121\u7dda\u96fb\u96dc\u8a0a\u5f71\u97ff,\u4e14\u7522\u751f\u7684\u5e72\u64fe\u5f88\u5c11,\u9069\u5408\u6578\u64da\u8cc7\u6599\u901a\u4fe1\u4e0a<\/p>\n\n\n\n
\u53c3\u8003\u4f86\u6e90
http:\/\/wiki.iiietc.ncu.edu.tw\/mediawiki\/index.php?title=Wireless_802.11_PHY_%E5%90%84%E7%A8%AE%E6%A8%99%E6%BA%96<\/p>\n","protected":false},"excerpt":{"rendered":"