Wlan無線通訊實驗

802.11Wlan無線通訊實驗10748215LiubinJune,2008實驗?zāi)康膶W(xué)習(xí)802.11相關(guān)知識技術(shù)使用無線網(wǎng)卡工作Linux下最強Driver：Madwifi網(wǎng)卡配置和實時數(shù)據(jù)搭建802.11b/gAccessPointUDP數(shù)據(jù)通訊不同802.11標(biāo)準(zhǔn)調(diào)節(jié)數(shù)據(jù)包大小、發(fā)送頻率不同連接方式tcp通訊統(tǒng)計和繪圖目的不是得到實驗結(jié)果動手能力感性認(rèn)識研究基礎(chǔ)實驗設(shè)備服務(wù)器×1Unbutu7.04Server+Madwifi0.9.4+ApacheCiscoAirNetPI21AG(802.11a/b/g)wirelessAdapterNetGearWAG311WirelessPCIAdapter(802.11a/b/g)Windows客戶端×2ThinkPadT60IntelPRO/Wireless3945ABGNetworkConnectionNormalHostCiscoAirNetPI21AG(802.11a/b/g)wirelessAdapter實驗設(shè)備Linux下Atheros

芯片網(wǎng)卡驅(qū)動開源，許多l(xiāng)inux發(fā)行版包括在有版權(quán)的硬件抽象層（HAL）上工作替代品->ath5k比windows下更強勁模擬AP、station等Mode：sta、adhoc、ap、monitor、wds、ahdemo一塊網(wǎng)卡可以同時模擬多個AP手動設(shè)置信道、scan、associate……可能有bug服務(wù)器的搭建-1安裝Madwifi新增ath_pci等內(nèi)核模塊rmmodath_pcimodprobeath_pciautocreate=apwlanconfigath0destroywlanconfigath0createwlandevwifi0wlanmodeapiwconfigath0essidMobleCourseiwprivath0mode0iwconfigath0channel6ifconfigath0netmaskup服務(wù)器的搭建-2Ifconfig、iwconfig、wlanconfig等命令I(lǐng)EEE802.11gESSID:"luoboo"Nickname:""Mode:MasterFrequency:2.437GHz(Channel6)AccessPoint:00:40:96:B2:FE:E5BitRate:0kb/sTx-Power:18dBmSensitivity=1/1Retry:offRTSthr:offFragmentthr:offEncryptionkey:offPowerManagement:offLinkQuality=24/70Signallevel=-72dBmNoiselevel=-96dBmRxinvalidnwid:2518Rxinvalidcrypt:0Rxinvalidfrag:0Txexcessiveretries:0Invalidmisc:0Missedbeacon:0服務(wù)器的搭建-3wlanconfigath4listchannel：Channel1:2412Mhz11gChannel48:5240Mhz11aDynamicChannel2:2417Mhz11gChannel50:5250Mhz11aStaticChannel3:2422Mhz11gChannel52:5260Mhz11aChannel4:2427Mhz11gChannel56:5280Mhz11aDynamicChannel5:2432Mhz11gChannel58:5290Mhz11aStaticChannel6:2437Mhz11gChannel60:5300Mhz11aChannel7:2442Mhz11gChannel64:5320Mhz11aChannel8:2447Mhz11gChannel149:5745Mhz11aChannel9:2452Mhz11gChannel152:5760Mhz11aStaticChannel10:2457Mhz11gChannel153:5765Mhz11aDynamicChannel11:2462Mhz11gChannel157:5785Mhz11aChannel36:5180Mhz11aChannel160:5800Mhz11aStaticChannel40:5200Mhz11aDynamicChannel161:5805Mhz11aDynamicChannel42:5210Mhz11aStaticChannel165:5825Mhz11aChannel44:5220Mhz11a服務(wù)器的搭建-4wlanconfigath4liststa:ADDRAIDCHANRATERSSIDBMIDLETXSEQRXSEQCAPSACAPSERPSTATEMODE00:40:96:b2:fe:e9114912M16-7918025913272E023NormalWME00:1b:77:09:0f:47214954M41-541201717315200Es0f3NormalWMEUAPSDQoSInfo:0x0f,(VO,VI,BE,BK)=(1,1,1,1),MaxSpLimit=NoLimit實驗環(huán)境-1實驗室1717房間實驗環(huán)境-2實驗室1717房間實驗環(huán)境-單位dB純粹的比值，沒有單位10log（甲功率/乙功率）dBi和dBddBi和dBd是表示天線功率增益的量dBmdBm是一個表示功率絕對值的值（也可以認(rèn)為是以1mW功率為基準(zhǔn)的一個比值）計算公式為：10log（功率值/1mw）實驗環(huán)境-單位網(wǎng)卡接受一個幀、一個位環(huán)境噪聲熱噪聲SINR：Signal

toInterferenceplusNoiseRatioSINR=S/(I+N)

接收信號強度指示（RSSI）(S+I)/N實驗環(huán)境-3實驗室1717房間實驗環(huán)境-802.11a實驗環(huán)境-4實驗室1717房間實驗環(huán)境完成！11a()11g()WirelessPKUClentHost()Notebook()實驗工具–控制網(wǎng)卡Windows下WireSharkWirelessMonWifiHopperCirondWinc(adhoc)DevicespecificIBMAccessConnectionsCiscoAironetDesktoputility實驗工具–統(tǒng)計繪圖UDPMgen(Multi-Generator)調(diào)節(jié)發(fā)送速率、UDP包的大小Period、possion、burst記錄發(fā)送和接受traceTRPR對tcpdump的輸出等trace文件統(tǒng)計分析生成可以用gnuplot繪圖的數(shù)據(jù)GnuPlotTCPwget實驗設(shè)計和結(jié)果11a()11g()Notebook()實驗一、UDP通訊實驗11avs11g[50-110040][5040-1400][50-11001024]ClentHost()[50-110040]11a[50-110040]11g[5040-1400]11a[5040-1400]11g[50-11001024]11a[50-11001024]11g實驗一補充前面的實驗都沒有達(dá)到峰值11a和11g傳輸udp最大Throughput？補充實驗[50-60001024]11a最大Throughput11g最大Throughput實驗二11g()Notebook()ClentHost()ClientHost和Notebook都連接到AP11g上競爭從AP傳輸UDP流競爭udp[18001024]實驗三11a()11g()WirelessPKUClentHost()Notebook()ClientHost和Notebook分別連接APWirelessPKU、11a、11g上傳輸UDP包1分鐘對比p2pudp流[8001024]實驗四TCP傳輸試驗方法使用wget從server下載dummy.zip客戶端之間使用ftp文件下載dummy.zipTCP流在無線環(huán)境下時變形十分明顯有時連接甚至無法建立！11a和11g的單鏈路傳輸最優(yōu)平均值：3.81M/s