電子航法研究所研究発表会（第14回平成 26年6月） ̔ɽσʔλϦϯΫ LDACS1 ͷϏοτޡΓಛੑ ࢹ௨৴ྖҬ 1. ˞ંɹ५ɺԘ֨ ݟҰɺॅ୩ɹହਓɺੴग़ɹ໌ ͡Ίʹ ࠃࡍຽؒߤۭؔػɺকདྷͷߤۭ௨৴धཁͷ ૿େʹඋ͑ΔͨΊɺߴσʔλϦϯΫγεςϜ ͷٕज़తݕ౼ΛԤถڞಉ࡞ ۀFCSʢFuture Com- munication StudyʣʹҕͶͨɻFCS ࠷ऴใࠂͰ ɺ৽ͨͳσʔλ௨৴γεςϜ͕ඞཁͰ͋Δͱ ͷݟղΛ͓ࣔͯ͠Γɺ·ͨ༸্௨৴ɺରۭ௨৴ɺ ਤ 1 LDACS1 εʔύϑϨʔϜߏ [2] ۭߓ໘௨৴ͱɺ௨৴༻్ʹԠͯ͡దͳߤۭ௨ ৴γεςϜΛબ͠༻͢Δ͜ͱΛਪ͍ͯ͠ Δɻରۭ௨৴ʹ͓͍ͯɺVHF ଳͰ༻͍ΒΕ ͍ͯΔߦݱͷ VDLʢVHF Digital LinkʣMode2 ACARSʢAircraft Communications Addressing and Reporting SystemʣʹΘΔσʔλ௨৴γε ςϜީิͱͯ͠ɺL όϯυʹ͓͚Δߴσʔ λϦϯΫ LDACSʢL-band Digital Aeronautical Communications SystemʣΛఏҊ͍ͯ͠Δ [1]ɻ ͔͠͠Ͱ·ࡏݱͷͱ͜ΖɺLDACS ͷࣗ֨نମ͕ LDACS1[2] ͱ LDACS2[3] ͱ͍͏ 2 छྨͷ֨ن Ҋ͕ฒཱ͍ͯ͠Δஈ֊ʹཹ·͓ͬͯΓɺLDACS ͷຊ֨తͳ֨نԽʹ·͕͔͔ͩ࣌ؒΔͷͱ ਤ 2 ύΠϩοτ৴߸ஔྫ ߟ͑ΒΕ͍ͯΔɻ ͜Ε·Ͱʹిࢠߤ๏ͰॴڀݚɺLDACS ཧ ࣮ݧγεςϜΛ࡞͠ [4]ɺҰ෦ͷੑೳʹ͍ͭ ͯ[ ͖ͨͯ͠ূݕ5, 6]ɻຊใࠂͰ LDACS1 ʹ ͍ͭͯجຊతͳ௨৴ੑೳࢦඪͰ͋Δ BERʢBit Error Rate; ϏοτޡΓʣಛੑͷධՁ݁Ռʹͭ ͍ͯใࠂ͢Δɻ 2. LDACS1 ͷૹ৴ϑΥʔϚοτΛਤ 1 ʹࣔ͢ɻ ͞ 240 ms ͷεʔύϑϨʔϜΛجຊ୯Ґͱ͠ ͯɺ͞Βʹࡉ͔͍୯ҐͷϑϨʔϜʹׂ͍ͯ͠ Δɻ·ͨ FL ͱ RL ͱͰҟͳΔϑϨʔϜϑΥʔ LDACS1 ֓ཁ ϚοτΛ༻͍Δɻೋ࣍มௐͰ 50 ຊͷαϒΩϟ LDACS1 VDL Mode2 ͱҟͳΓ্→ ہ ϦΞΛ FFTʢFast Fourier TransformɺαΠζ 64ʣ ߤۭํہػͷ FLʢForward Linkʣͱߤۭہػ Ͱ࣌ؒ৴߸ʹม͢Δɻ͞ΒʹɺRL Ͱ 50 ຊ → ্ํہͷ RLʢReverse LinkʣͱͰผʑͷ पνϟωϧΛׂΓͯΔɻFL ্͔ہ Β OFDMʢOrthogonal Frequency Division Multiplexʣ৴߸Λ࿈ଓૹ৴͠ɺ֤ߤۭʹہػରͯ͠ݸ ͷαϒΩϟϦΞΛ͍पͷ 25 ຊͱߴ͍प ͷ 25 ຊͷ 2 ͭʹ͚ɺผʑͷϢʔβʹ༻͢ Δɻ·ͨɺOFDM Ͱνϟωϧਪఆʹ༻͢Δύ Πϩοτ৴߸ͷஔϑϨʔϜͷʹܕԠܾͯ͡ ผࢦఆ·ͨಉ࣌௨ใͷૹ͕ߦ͑Δνϟωϧ ΊΒΕ͍ͯΔɻྫͱͯ͠ɺਤ 2 ʹϢʔβσʔλ Ͱ͋ΔɻҰํɺRL ্͔ہΒͷཁʹٻԠͯ͡ ૹʹ༻͍Δ FL σʔλϑϨʔϜͱ RL σʔλϑ ׂΓͯΒΕͨߤۭ͕ہػόʔετঢ়ʹૹ৴͢ ϨʔϜͷύΠϩοτ৴߸ஔΛࣔ͢ɻ Δ OFDMA-TDMAʢOrthogonal Frequency Division Multiple ɹ Access–Time Division Multiple AccessʣํࣜͷνϟωϧͰ͋Δɻ ͳ͓ɺड৴ੑೳධՁʹΘΕΔࢀর BER ʮޡΓగਖ਼ޙͷ BER ͕ 10−6 ʯͱنఆ͞Ε͍ͯΔ [2]ɻLDACS1 ͷओཁॾݩΛද 1 ʹࣔ͢ɻ － 41 － 電子航法研究所研究発表会（第14回平成 26年6月） LDACS1 ओཁॾݩ ༻पଳ ෳ৴ํࣜ ΞΫηεํࣜ มௐํࣜ νϟωϧ෯ Ϗοτૹ ֎ූ߸ ޡΓగਖ਼ ූ߸ FFT αΠζ αϯϓϦϯά࣌ؒ OFDM γϯϘϧ αϒΩϟϦΞ αϒΩϟϦΞִؒ LDACS1 BER performances in FL Data frame, under AWGN channel 100 960—1164[MHz] QPSK+FEC QPSK 16QAM+FEC 16QAM 64QAM+FEC 64QAM 10-1 पׂ 10-2 OFDMA 4/16/64QAM+OFDM 498.05[kHz] x 2 833.33—2500.0[kbps] Bit Error Rate ද1 10-3 10-4 10-5 ϦʔυιϩϞϯ ʢύϯΫνϟυʣΈࠐΈ 10-6 64 1.6[µs] 120[µs] 50 9.765625[kHz] 10-7 2 4 ਤ4 6 8 10 12 14 16 18 C/N [dB] 20 22 24 26 28 30 FL σʔλϑϨʔϜมௐํࣜผ BER ಛੑ ఆٛ͞Ε͍ͯΔɻϑΣʔδϯάͷͳ͍੩త௨৴ ڥԼͰͷมௐํࣜผ FL σʔλϑϨʔϜ BER ಛੑΛਤ 4 ʹࣔ͢ɻޡΓగਖ਼લ BER ཧ্ͷ ಛੑʹൺ͍ͣΕྼԽ͕ݟΒΕΔ͕ɺ4QAM ྼԽ߹͍͕গͳ͘ྑͳಛੑͰ͋ͬͨɻ· ͨޡΓగਖ਼લ BER ͕ 10−2 ʙ10−1 ఔҎԼͰగ ਖ਼ූ߸͕ޮ͖ɺ4QAM Ͱ C/N = 8 [dB]ɺ64QAM Ͱ C/N = 14 [dB] ͰޡΓగਖ਼ޙͷ BER ͕ 0 ͱ ͳͬͨɻ ਤ 3 ࣮ߏݧਤ 4.2 3. पγϑτੑ υοϓϥγϑτʹද͞ΕΔΑ͏ʹɺड৴৴߸ ࣮ํݧ๏ LDACS ཧ࣮ݧγεςϜɺPC ͱ৴߸ૹ ड৴ϑϩϯτΤϯυ USRPʢUniversal Software Radio PeripheralʣͰߏ͞ΕΔ [4]ɻPC ্Ͱ৴߸ ॲཧϥΠϒϥϦ GNURadio[7] Λ༻͍ͨ LDACS ཧಈ࡞ϓϩάϥϜΛΒ࣮ͤͯݧΛߦ ͬͨɻ ຊߘͰɺਤ 3 ʹࣔ͢Α͏ʹɺૹ৴৴߸ҙ ൃܗੜͰثϓϦΞϯϒϧΛՃͨ͠ϑϨʔϜ Λ܁Γฦ͠ൃੜͤ͞ɺड৴ଆͷ PC ͰޡΓగਖ਼લ ޙͷ BER Λଌఆͨ͠ɻͳ͓ɺຊߘͰ LDACS1 ͷ֤छϑϨʔϜͷ͏ͪ FL σʔλϑϨʔϜʢ ͞ 52 OFDM γϯϘϧʣ ͼٴRL σʔλϑϨʔϜ ʢ͞ 6 OFDM γϯϘϧʣΛରͱͨ͠ɻ ʹपγϑτ͕ൃੜ͢Δ͜ͱ͕͋Δɻ৴߸ൖ ૹपʹपγϑτΛൃੜͤ͞ड৴ͤ͞ ͨ߹ͷ BER ಛੑΛਤ 5 ʹࣔ͢ɻFL Ͱप γϑτ͕ ±1.5 kHz ͰޡΓగਖ਼ ޙBER= 0 Ͱ ͋ͬͨɻ͜Εൖૹप 970 MHz ͷ߹ 1670 km/hʢ900 ϊοτʣͷҠಈʹ૬͢Δɻ Ұํ RL Ͱγϑτ͕ ±300 Hz ఔͰޡΓగਖ਼ ޙBER> 10−6 ͱͳͬͨɻ 4.3 ϑΣʔδϯάڥ ߤۭػͷҠಈʹ͍ϚϧνύεϑΣʔδϯά ͕ൃੜ͢Δɻจ[ ݙ2]App.A ʹ͋Δදతͳ௨৴ νϟωϧϞσϧྫΛࢀߟʹͯ͠ɺϑΣʔδϯά ڥΛද 2 ͷΑ͏ʹఆΊ BER ಛੑΛଌఆͨ͠ɻਤ 4. BER ಛੑ࣮݁ݧՌ 4.1 ੩త௨৴ڥ LDACS1 ͷ Ұ ࣍ ม ௐ QPSKʢQuadrature Phase Shift Keyingʣ=4QAMʢQuadrature Amplitude Modulationʣɺ16QAMɺ64QAM ͷ 3 छྨ͕ 6 ʹ ENR ڥɺਤ 7 ʹ TM ڥɺਤ 8 ʹ APT ͚͓ʹڥΔ BER ಛੑΛࣔ͢ɻFL ENRɺTM Ͱࢀর BER ʹରԠ͢Δ C/N ͕ͦΕͧΕ 9 dBɺ 15 dB ͱͳ͕ͬͨɺAPT Ͱࢀর BER ʹରԠ ͢Δ C/N ಘΒΕͳ͔ͬͨɻ·ͨɺRL ʹ͍ͭ － 42 － 電子航法研究所研究発表会（第14回平成 26年6月） ද2 ϑΣʔδϯάڥઃఆ ϑΣʔδϯάλΠϓ Ԇ [µs] ϐϡΞυοϓϥ 0 ϨΠϦʔ 0.3 ϨΠϦʔ 15 ϥΠεʢK = 10[dB]ʣ 0 ϨΠϦʔ 0 ໊ڥ ENRʢΤϯϧʔτʣ TMʢλʔϛφϧʣ APTʢۭߓ໘ʣ ݮਰ [dB] ࠷େυοϓϥγϑτ [Hz] 0 16 22 0 0 997 603 -594 498 330 BER performance vs frequency shift LDACS1 BER performances (TM) 100 100 10-1 10-1 10-2 FL+FEC FL RL+FEC RL 10-3 Bit Error Rate BER CNR=20[dB] 10-2 10-4 10-3 10-4 10-5 10-5 10-6 10-6 10-7 -1500 -1200 -900 -600 -300 0 300 600 900 1200 10-7 1500 FL+FEC FL RL+FEC RL 0 2 4 6 8 10 12 Frequency shift [Hz] LDACS1 BER performances (ENR) 20 22 24 26 28 30 28 30 LDACS1 BER performances (APT) 100 10-1 10-1 10-2 10-2 Bit Error Rate Bit Error Rate 18 ਤ 7 TM ڥBER ಛੑ 100 10-3 10-4 10-5 10-3 10-4 10-5 10-6 10-6 FL+FEC FL RL+FEC RL 0 2 4 ਤ6 6 8 10 C/N [dB] 12 14 16 18 10-7 20 ENR ڥBER ಛੑ FL+FEC FL RL+FEC RL 0 2 4 6 8 10 12 14 16 C/N [dB] 18 20 22 24 26 ਤ 8 APT ڥBER ಛੑ ͍ͯͣΕࢀর BER ʹରԠ͢Δ C/N ಘ ΒΕͳ͔ͬͨɻ 4.4 16 C/N [dB] ਤ 5 पγϑτੑ 10-7 14 ʢDecision Feedback EqualizerʣΞϧΰϦζϜΛ ࣮͍͕ͯͨ͠ɺFL ͱ RL ͱͰಛੑ͕େ͖͘ҟ ͳͬͨɻ͜Εɺਤ 2 ͔ΒΘ͔ΔΑ͏ʹ FL ߟ ຖ OFDM γϯϘϧʹύΠϩοτ৴߸͕ஔ͞Ε पγϑτੑϑΣʔδϯάڥԼͰͷ ͍ͯΔͷʹରͯ͠ɺRL ύΠϩοτ৴߸ͷ࣌ؒ BER ಛੑಛʹ RL ͰͷྼԽ͕ݦஶͰ͋ͬͨɻ 4.2 અͷपγϑτੑͰɺFL ±1.5 kHz ·Ͱेͳੑ͕͋ͬͨͷʹରͯ͠ɺRL ±300 Hz ͷγϑτͭ·Γ 334 km/hʢ180 ϊοτʣ Ͱड৴ BER ج४Λ͑ͨɻࠓճύΠϩοτ৴ ߸Λར༻ͨ͠Խॲཧͱͯ͠ɺҰൠతͳ DFE తஔ͕ඈͼඈͼͰ͋ΔͨΊʹɺຖ OFDM γϯ ϘϧͰͷԽॲཧͱͳΒͣɺదͳνϟωϧ ਪఆ͕ߦ͑ͳ͔ͬͨͷͱߟ͑ΒΕΔɻͦ͜Ͱɺ RL ͷύΠϩοτ৴߸ஔʹదͨ͠ૠԽΞϧ ΰϦζϜͰಉ༷ͷपγϑτੑΛٻΊͯΈ ͨͱ͜Ζɺਤ 9 ͷΑ͏ʹ ±700 Hz ఔ·Ͱੑ － 43 － 電子航法研究所研究発表会（第14回平成 26年6月） FL ͱ RL ͱͰେ͖͘ҟͳΔ͜ͱ͕Θ͔ͬͨɻಉ BER performance vs frequency shift 100 ҰͷԽΞϧΰϦζϜΛ༻͍ͨ߹Ͱͷಛੑ͕ 10-1 BER CNR=20[dB] ҟͳΔ͜ͱ͔ΒɺύΠϩοτ৴߸ஔ͕Өͯ͠ڹ RL+FEC (interpolation) RL (interpolation) 10-2 ͍Δͱ͑ݴΔɻͭ·ΓɺFL ͱ RL ͱͰͦΕͧΕ దͳ BER ಛੑΛಘΔͨΊʹݸผʹԽΞϧ 10-3 ΰϦζϜΛݕ౼͍ͯ͘͠ඞཁ͕͋Δɻ -4 10 5. 10-5 10-7 -1500 ·ͱΊ LDACS1 Ͱ FL ͱ RL ͱͰϑϨʔϜߏٴ 10-6 -1200 -900 -600 -300 0 300 Frequency shift [Hz] 600 900 1200 ͼύΠϩοτ৴߸ஔ͕ҟͳΓɺಉҰͷԽΞϧ 1500 ΰϦζϜͰेͳ BER ಛੑಘΒΕͳ͍͜ͱ ਤ 9 पγϑτੑʢૠԽʣ ͕Θ͔ͬͨɻ·ͨϨΠϦʔϑΣʔδϯάͰڥ ेͳޡΓగਖ਼͕ߦΘΕͣɺσʔλͷ࠶ૹ͕ස ͕վળ͞Εͨɻͳ͓ɺLDACS1 ड৴ػͷड৴ײ ఆٛͰҠಈ 850 ϊοτʹ૬͢Δप γϑτ࣌ʹରԠ͢Δ͜ͱ͕ٻΊΒΕ͓ͯΓ [2]ɺRL ʹ͍ͭͯ͞ΒͳΔվળ͕ඞཁͱߟ͑Β ΕΔɻ ਤ 6ɺਤ 7ɺਤ 8 ͷ֤ϑΣʔδϯάڥԼͷ BER ಛੑͰɺԽॲཧલड़ͷ DFE ΞϧΰϦ ζϜͰߦͬͨɻFL Ͱ APT ͷΑ͏ͳϨΠϦʔ ϑΣʔδϯάͰڥ C/N ͕ߴͯ͘ BER ͕ େ͖͘ɺϓϩτίϧ্ҐͰͷ࠶ૹߏػʹΑ ΔσʔλิঈΛซ༻͢Δඞཁ͕͋ΔɻҰํͰɺ ENR TM ͷΑ͏ͳ͍ڧΛड͚ΒΕΔ Ͱڥߴ͍ C/N ͰޡΓగਖ਼͕ޮ͖ɺBER Λ ͑Δ͜ͱ͕Ͱ͖ͨɻ͔͠͠ɺRL Ͱ 3 छྨͷ ڥͷ࠷ྑͰޡΓగਖ਼ ޙBER ͕ 0.08 ఔҎ ্͋ͬͨͨΊɺ͜ͷঢ়ଶͰ࠶ૹ͕සൟʹൃੜ͠ σʔλૹʹෆదͰ͋ΔɻRL ʹ͍ͭͯԽΞ ϧΰϦζϜΛૠԽʹมߋͨ͠ͱ͜ΖɺENR ʹ͍ͭͯ C/N = 30 [dB] ͰޡΓగਖ਼ ޙBER ͕ 0.3 ఔͱґવߴ͔ͬͨɻENR ͱ 2 Ԇͷ߹͞ΕͨΤϯϧʔτඈߦதͷ௨৴Λ ఆͨ͠ൖϞσϧͰ͋Δ͕ɺ࠷৴߸ৼ෯͕େ͖ ͍ͷυοϓϥγϑτ͕ 1 kHz ͱେ͖͘ લड़ͷपγϑτੑͷൣғΛ͍͑ͯΔͨ Ί C/N ʹΑΒͣ BER ͕ྼԽͨ͠ͷͱߟ͑Β ΕΔɻ·ͨ APT ͱ TM ͰૠԽΞϧΰϦζ ϜʹΑͬͯ BER ಛੑͷվળݟΒΕ͕ͨɺ͍ͣ Ε FL ͷ݁ՌΑΓѱ͔ͬͨɻಛʹ APT ͷΑ͏ ͳϨΠϦʔϑΣʔδϯάͰڥσʔλͷ࠶ૹ ͕සൃ͢ΔՄೳੑ͕͋Δɻ Ҏ্ͷ݁ՌΑΓɺLDACS1 ͷ BER ಛੑ ൃ͢ΔՄೳੑ͕͋Δɻࠓޙ FL ͱ RL ʹͦΕͧ Εదͨ͠ԽΞϧΰϦζϜΛٻΊɺධՁ͍ͯ͘͠ ༧ఆͰ͋Δɻ·ͨɺԽҎ֎ʹ৴߸ಉظͷॲ ཧ͕ड৴ੑೳΛࠨӈ͢Δ͜ͱ͔Βɺ͜ΕΒʹ͍ͭ ͍ͯͯ͘͠ূݕ༧ఆͰ͋Δɻ ࢀߟจݙ [1] Nicolaos Fistas, Brent Phillips, and James Budinger. Future communications study — action plan 17, final conclusions and recommendations report. In 26th DASC, pp. 1–14. , 4.B.6, IEEE, Oct 2007. [2] EUROCONTROL. Updated LDACS1 System Specification. SESAR Joint Undertaking, Aug 2011. [3] EUROCONTROL. L-DACS2 System Definition Proposal. Deliverable D2, EUROCONTROL, 2009. [4] ં५, ॅ୩ହਓ, ੴग़໌. ରۭσʔλϦϯΫ LDACS ཧͷ࣮. ୈ 11 ճಠཱߦ๏ਓ ిࢠߤ๏ൃॴڀݚදձߨԋ֓ཁ, pp. 25–28, June 2011. [5] ં५, ॅ୩ହਓ, ੴग़໌. ߤۭ༻ߴσʔλ ϦϯΫ LDACS ͷ BER ಛੑ. ిࢠใ௨৴ ֶձ ٕज़ڀݚใࠂ SANE, Vol. 112, No. 360, pp. 37–42, Dec. 2012. [6] Jun KITAORI. Results of LDACS PHY BER performances with GNU Radio. ICAO ACP WG-M20/IP-8, Jan 2013. [7] Eric Blossom. Gnu radio: tools for exploring the radio frequency spectrum. Linux J., Vol. 2004, No. 122, pp. 4–, June 2004. － 44 －
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