THE HISTORY OF OFDM STEPHEN B. WEINSTEIN Group 3:      HỌC VIỆN CÔNG NGHỆ BƯU CHÍNH VIỄN THÔNG contentS •   !"#$%&'!(  ) )(#$ ) )*&$&  '$*!()*& "$*)""*+  $*! $), "*')$-!'!"$++*$*!  *&!"$ & ),  .*+' "*/$! '!*&*&+ $%!$ '$& '$*!  *&!"$ & ),  .*+' "*/$! '!*&*&+ $%!$ '$& '$*! ! '$++*$*!) The fdm background •  * 012345 6768664 9 :67;4 4;7 <4 7; =>78> 76 87 ;?  76>68 74=44; >6 @  46:6> ;76?6 ?;=7;6>4  =69:4;=>78>6AB  "6C69:4;=>78>6AB" • *0D035"?;>;:;64>4=E47:6@6696=;47769@&6;6)C65=F;76()$=)B>;8458874<7 ;6@46@99;6844@96> • *0D015$G968>;6974;<E:6B6>4476=7746;7B4;B4@6?6C6649686764 The fdm background • *0DH3456I64476=4699;@>6496@9=8>796=;9>7;974=776987;I33=>64 • *760D2345"64476=4<79:9>4@6>4?;:;64>4@657;@668>69@J"9864476=4 • 64<67;748;@>6=<746>9774=44;9;?6C6K'"L6>4K9>76)<746:66>947;7696>4L<47;; @M7;E6B69"5;6779776>644?9694@6>4 • 6468;@>6=46;:6;=69@"7;@6;=6=;6;=8>6764476=4!" FDM had two drawbacks: N6<476;?46<6>644?6C64867=94864@67<66764@6>4 N6>6;=8>6A7;?=>78>7;?46876=;9>7;4?;769??6674@6>4 *!"4476=469;=8>6A97O  P5764@6>4>45  6=7>>;7;;>964876;:6>884867 '67>9?>>B;46B;>>;??8>464964>7!"4867  DENSE SUBCHANNELS ( ) ( ) ( ) ( ) 2 , / , 0 –1, 1 ; 0 0 ; 0 (1) ( ) n n n n s t a g t exp j f t f n T n N g t t T g t t hoac t T π = = ≤ ≤ = < < = ≤ ≥ DENSE SUBCHANNELS • $B8;7:646"K*"L;867;76K8;44@>;=8>6AL97@>;M O 3 5 0 5Q5 B0 P  667644=8>64577=676:>4J5;?76!"4>774764=;?764@6>4>496E69 C0 • !867;7666:694><776"5>M6 CI@7<767:66A8;6756;:647697 1 0 2{ } 2/ ( ) N k n n s a exp j nk N π − = = ∑ !"4476= DENSE SUBCHANNELS • 96:6>;86966>;97;4?;764864;?8>464596E69476;=@7;;?74=776E>7696>76475<7 @9>=769@747>>;:6>884867 4476=?;!"<76>B968696774=776E>764 DENSE SUBCHANNELS • )>7R@66A76969S4<;M7;;=8>6A975>>69!"B!$K;??467$L • ;4M;7@769?7666=6747;!"J!$587>>=?4768;6447;68>6=67;?B8;7"<7 JIB8;7" OFDM-OQAM implementation with staggered time-delayed subchannels(adapted from Saltzberg and Hirosaki ). 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