17-1©2010 Raj JainCSE574SWashington University in St. LouisRaj JainProfessor of Computer Science and Engineering Washington University in Saint LouisSaint Louis, MO 63130Audio/Video recordings of this lecture are available at:http://www.cse.wustl.edu/~jain/cse574-10/Aeronautical Aeronautical Wireless NetworksWireless Networks17-2©2010 Raj JainCSE574SWashington University in St. LouisOverviewOverview Aeronautical Wireless Applications Aeronautical Datalink Evolution L-DACS Interfering Technologies Coexistence Strategies17-3©2010 Raj JainCSE574SWashington University in St. LouisFrequency BandsFrequency Bands High Frequency (HF): 3-30 MHz Very High Frequency (VHF): 30-300 MHz L-Band: 950-1450 MHz - results from down conversion of satellite signals by LNB (Low noise block converters) L band 1 to 2 GHz S band 2 to 4 GHz C band 4 to 8 GHz X band 8 to 12 GHz Ku band 12 to 18 GHz K band 18 to 26.5 GHzKa band 26.5 to 40 GHz Ref: http://en.wikipedia.org/wiki/Ka_band17-4©2010 Raj JainCSE574SWashington University in St. LouisAeronautical Wireless ApplicationsAeronautical Wireless Applications Distance measuring equipment (DME) Passenger telephones Aeronautical Operation Control (AOC) Automatic Dependent Surveillance Broadcast (ADS-B) Airline administrative control Controller-Pilot Datalink Communication (CPDLC)¾ Voice communication between pilot and controller ¾ Data communication between plane and the towerThis lecture is limited to recent developments in voice/data communication17-5©2010 Raj JainCSE574SWashington University in St. LouisAeronautical DatalinksAeronautical DatalinksACARS VDL2VDL4LDLGSM E-TDMAAMACSL-DACS2P34B-AMCB-VHSWiMAXL-DACS1UAT1190ESPast Present FutureOFDMTDM17-6©2010 Raj JainCSE574SWashington University in St. LouisAeronautical Datalink Evolution (Cont)Aeronautical Datalink Evolution (Cont) ACARS (Aircraft Communications Addressing and Reporting System): ¾ Short telex-like messages between plane and ground.¾ Uses VHF (117.975 - 137 MHz) and Satellites¾ Uses HF in the polar region (HF ACARS) ¾ Developed by ARINC in 1978. Analog radio. VDL (VHS Digital Link): ¾ Four modes - 1, 2, 3, 4. Mode 1 was deleted in 1994.¾ VDL2 required in all aircrafts flying in Europe. 8-PSK over 25 kHz ⇒ 31.5 kbpsWidely Implemented since 199417-7©2010 Raj JainCSE574SWashington University in St. LouisAeronautical Datalink Evolution (Cont)Aeronautical Datalink Evolution (Cont)¾ VDL3 – Added digital voice to VDL2. Abandoned in 2004¾ VDL4 – Added aircraft-to-aircraft communication. No master ground station required. Developed in 2001. Limited deployment. UAT (Universal Access Transceiver):¾ 981 MHz¾ 1 Mbps channel rate using 3 MHz ¾ Each aircraft allowed to transmit one 16 or 32B message every second¾ Developed 2002 1090ES (1090 MHz Extended Squitter): Secondary surveillance radar (aka Mode S) with a “extended squitter” message that periodically announces position, velocity, time, and intent17-8©2010 Raj JainCSE574SWashington University in St. LouisQoS2EE--TDMATDMA Extended Time Division Multiple Access Developed by Hughes Network Systems. 1998-2001. Statistical Self Synchronization: Aircrafts measure guard times arrivals from other devices and adjust their clocks TDMA system like GSM. Slotted Structure and Multi-QoSPropagationGuard TimeSynch Data CRC DecayRamp upSlotQoS0 QoS1Dedicated Primary Slots for urgent messagesShared slots for Other messagesRef: "The E-TDMA Concept: Towards a new VDL strategy - Some key issues & possible way forward," AMCP-WG/C2-WP26 7-11 May 2001, http://www.icao.int/anb/panels/acp/WG/C/wgc2/wgc2_wp26.ppt17-9©2010 Raj JainCSE574SWashington University in St. LouisLDLLDL L-Band Digital Link VDL3 shifted to L-Band TDMA frame structure with 120 ms frames and 5 slots/frame (like GSM) Some of the slots can be allocated for voice. Others are used for data.17-10©2010 Raj JainCSE574SWashington University in St. LouisAMACSAMACS All Purpose Multichannel Aviation Communications System (AMACS). Completed October 2007 Based on E-TDMA slots and QoS. xDL4 broadcast. GSM/UAT coding (GMSK) Flexible 100 kHz, 200kHz, or 400 kHz spectrum in 960-975 MHz band 0.1 ms ramp up 0.9ms guard time ⇒ 150 nm cell radiusRef: L. Deneufchatel and L. Johnsson, "All-purpose Multi-channel Aviation Communication System (AMACS)," AGC FG/4 meeting, 13 September 2007, http://www.eurocontrol.int/nexsat/gallery/content/public/Steering%20Group/Meeting9/DAY1/AI2_3_2_2_1AMACS.pdfUp1 CoS1 Up2 CoS2Shared slotsDedicated slots Acks, CTS, ReservationsReserved UplinkInser-tion17-11©2010 Raj JainCSE574SWashington University in St. LouisBB--VHFVHF Funded by European Commission 6thFramework Program 118-137 MHz VHF band Multi-Carrier Code-Division Multiple Access (MC-CDMA) = OFDM + CDMA Each bit is encoded as multiple chips and these chips use separate subcarriers of OFDM Excessive noise in one subcarrier ⇒ loss of one chip ⇒ Symbol can still be decoded Time division duplexing (TDD) 2 kHz subcarrier spacingRef: http://www.b-vhf.org17-12©2010 Raj JainCSE574SWashington University in St. LouisBB--AMCAMC Broadband Aeronautical Multicarrier Systems in L-Band B-VHF extended to L-Band Air-to-Ground mode: OFDM and FDD Frequency division duplexing ⇒ Two smaller (500 kHz) bands rather than on one (1 MHz) band 10 kHz subcarrier spacing ⇒ Increased Doppler spread required for higher frequency OFDMA rather than MC-CDMA 240 ms super frame = 4 multi-frames of 58.32 ms + 6.72 ms management frame Ground station uses management frame for broadcastsAircraft uses management frames for “random access” Air-to-Air mode would require a common control channel and a global time reference ⇒ could not be designed.Ref: http://www.eurocontrol.int/communications/public/standard_page/LBANDLIB.html17-13©2010 Raj JainCSE574SWashington University in St. LouisP34P34 Project 34 of Electronic Industries Association (EIA) Public safety radio system connecting mobile radios and fixed network and direct radio to radio communication 187.5 km sectors 50, 100, 150 kHz channels in 960-1164 MHz band17-14©2010 Raj JainCSE574SWashington University in St. LouisLL--DACSDACS L-band Digital Aeronautical Communications System Type 1 and Type 2 Both designed for Airplane-to-ground station communications Airplane-to-airplane in future extensions Range:
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