ANALYSIS ON CHARACTERISTICS OF AERONAUTICAL WIRELESS CHANNELS

Vol.28 No.2JOURNAL OF ELECTRONICS (CHINA)March 2011ANALYSIS ON CHARACTERISTICS OF AERONAUTICAL WIRELESSCHANNELS'Wang ZhenbangWang ZhenyongLi Zhuoshi(Harbin Institute of Technology, Harbin 150001, China)Abstract In aeronautical mobile communication systems, wireless channels characteristics are dif-ferent in scenarios of Parking, En-Route, Taxi, and Arrival/Take-off. By considering fading types,power spectrum density and delay characterization of aeronautical wireless channels, typical parame-ters of aeronautical wireless channels model are investigated to analyze characteristics of aeronauticalwireless channels.Key words Aeronautical mobile communication; Channel characteristics; Channel modelsCLC indexTN911.72DOI 10.1007/s11767-011-0568-yI. Introductionfading type. And in other scenarios, the receivedIn wireless communication， it is generallysignal usually includes LOS and scattering part,known that the problem of multi-path transmitwhich can lead to Rician fading. So it is necessarybetween the receiver and the transmitter can causeto model and study each scenario5. This papermulti-path effectsh. The aeronautical channel ismainly analyzes aircraft-ground station commu-usually considered to consist of direct Line-Of-Sightnication link characterization different scenarios.(LOS) path and multi-path propagation, which isII. Aeronautical Channels Characteri-called Rice fading channel. And the multi-pathzationpropagation part is generated by the reflecting andIn the aircraft-ground station communication,scattering of microwave in the transmitting envi-different status of aircraft can lead to differentronment. Besides the channel characterization thatcharacterizations which are determined by fadinggeneral satellite mobile communication has, airtypes, Doppler spectrum, and the delay charac-satellite mobile communication has other specialterization, etc.. And the multi-path characteriza-characterizations. On one hand, the airframe retion of scattering is determined by Doppler powerflecting, the ground/sea reflecting and the LOSspectrum and delay power spectrum, but it ispart cannot be blocked. On the other hand, sinceduring one arrival/take-off process, the aircraftnecessary to consider the LOS part and the scat-needs to experience taxi scenario, take-off scenario,tering part separately. To construct exact channelflying over ground station scenario, en-route sce-model, aeronautical channel is generally consideredto consist of parking scenario, en-route scenario,nario, and arrival scenario with different commu-taxi scenario, arrival/take -off scenario. Whennication conditions. In the aircraft-ground stationaircraft is on the parking apron, in the hangar orcommunication, different scenarios of aircraft canmoves at quite low speed, it is usually regarded asgenerate different fading typesl2司Genrally, in thethe parking scenario. Because of the influence fromparking scenario, because of the influence of thebuildings around, no LOS signal exists betweenparking apron and hangar, LOS does not exist,aircraft and ground station. At this time, thewhich can lead to Rayleigh fading- the worstchannel is fully made up of the scattering part,which corresponds to the typical COST-207 urban1 Manuscript received date: October 9, 2010; revised date:fading environment. When aircraft is in the taxiMarch 23, 2011.scenario, the environment around is comparativelyCommunication author: Wang Zhenyong, born in 1977,broad, an中国煤化工is considered tomale, Ph.D.. Harbin Institute of Technology, Harbinconsist ofMHC N M H G scattering part,150001, China.Email: ZYWang@hit.edu.cn.which corresponds to the typical COST-207 ruralWANG et al Analysis on Characteristics of Aeronautical Wireless Channels211fading environment. When aircraft is in the en-the en-route scenario and the taxi scenariol7.route (after aircraft is off ground), the communi-These different scenarios can be defined by thecation can possibly happen between aircraft andfading type, Doppler power spectrum and delayground station, in which the channel consists ofpower spectrum8 10. The ratio of the LOS powerLOS part and scattering part, and the LOS part isand the scattering power is called Rice factor:dominant. The arrival/ take-off scenario describesKpicin =a'/c, a2 is the LOS power, c2 is thethe process in which aircraft leaves the altitude andmulti-path average power. If KRician tends to be 0, ,speed of the en-route scenario and is going to land,it will be Rayleigh fading. On the other hand, if itor aircraft leaves the speed of the taxi scenario andtends to be infinite, it will be Additive Whiteis going to take off. This scenario is usually in-Gaussian Noise (AWGN). The typical simulationfluenced by the shadow by the building around theparameter for aircraft -ground station communica-airport, but the influence extent is between that oftion channel model is shown in Tab.1.Tab. 1 Tbe typical parameters of aeronautical wireless channelsParametersParking scenarioTaxi scenarioTake-off scenarioEnroute scenario0-5.50-1525-15017-440Aircralt speed U (m/s)Typical value: 5.5Typical value: 15Typical value: 85Typical value: 2506-200Maximum time delay (us)7.00.7.Typical value: 33Nunmber of path N209-202-20Rician factor (dB)6.Iam/1o_ factor-1.Start angle of beam (°)0.0-90.0178.25End angle of beam 4e% (°)360.0+90.0181.75Delay function of multi pathexpexChange rate of time delay (LS)01/9.21.0Rayleigh process.IHI. En-route Scenario(2) Doppler power spectrum: the en-route isThe en-route scenario is the process in whichthe process with rapid decline. Since the multi-pathaircraft is in the air and meanwhile communicatessignal is not all-directional, which leads to thewith ground station or with other aircrafts. Whenresult that the Doppler power spectrum does notaircraft is in the air, channel is supposed as asatisfy the Jakes spectrum. It is considered that thetwo-ray model, in which one ray is the LOS signaldirection of multi-path signal is reverse to that ofand the other ray is the Rayleigh fading scatteringthe LOS signal. And the beam width of multi-pathsignal. Moreover, the relative speed between thesignal is 3.5° and distributes uniformly, whichreceiver and the transmitted is quite high. Mean-means that the Doppler spectrum is not 0 withinwhile, the scattering part distributes non- uniformly,3.5°，and satisfies Jakes spectrum.which means that the beam width is less than 360°，and 3.5° is generally supposed to be the beamPo (f.)=-|f|