81:
In the downlink (one base station transmitting to one or more terminals), MC-CDMA typically reduces to Multi-Carrier Code
Division Multiplexing. All user signals can easily be synchronized, and all signals on one subcarrier experience the same radio channel properties. In such case a preferred system
48:
MC-CDMA spreads each user symbol in the frequency domain. That is, each user symbol is carried over multiple parallel subcarriers, but it is phase-shifted (typically 0 or 180 degrees) according to a code value. The code values differ per subcarrier and per user. The receiver combines all subcarrier
52:
Since each data symbol occupies a much wider bandwidth (in hertz) than the data rate (in bit/s), a ratio of signal to noise-plus-interference (if defined as signal power divided by total noise plus interference power in the entire transmission band) of less than 0 dB is feasible.
363:
N. Yee, J.P.M.G. Linnartz and G. Fettweis, "Multi-Carrier CDMA in indoor wireless Radio
Networks", IEEE Personal Indoor and Mobile Radio Communications (PIMRC) Int. Conference, Sept. 1993, Yokohama, Japan, pp. 109–113 (1993: first paper proposing the system and the name
159:
is used as the modulation scheme, the data symbols on the individual subcarriers are spread in time by multiplying the chips on a PN code by the data symbol on the subcarrier. For example, assume the PN code chips consist of {1, −1} and the data symbol on the subcarrier is
371:
A. Chouly, A. Brajal, and S. Jourdan, "Orthogonal multicarrier techniques applied to direct sequence spread spectrum CDMA systems," in
Proceedings of Global Telecommunications Conference (GLOBECOM'93), pp. 1723–1728, Houston, Tex, USA, November
148:, called MC-DS-CDMA or MC/DS-CDMA, performs spreading in the time domain, rather than in the frequency domain in the case of MC-CDMA — for the special case where there is only one carrier, this reverts to standard
367:
K. Fazel and L. Papke, "On the performance of convolutionally-coded CDMA/OFDM for mobile communication system", IEEE Personal Indoor and Mobile Radio
Communications (PIMRC) Int. Conference, Sept. 1993, Yokohama, Japan,
222:, will be multiplied by the length-2 frequency-domain PN codes and placed on subcarriers 0 and 1, and these values on subcarriers 0 and 1 will then be multiplied by the length-4 time-domain PN code and transmitted on
72:
Wireless radio links suffer from frequency-selective channel interference. If the signal on one subcarrier experiences an outage, it can still be reconstructed from the energy received over other subcarriers.
49:
signals, by weighing these to compensate varying signal strengths and undo the code shift. The receiver can separate signals of different users, because these have different (e.g. orthogonal) code values.
375:
N.Yee, J.P.M.G. Linnartz and G. Fettweis, "Multi-Carrier-CDMA in indoor wireless networks", IEICE Transaction on
Communications, Japan, Vol. E77-B, No. 7, July 1994, pp. 900–904.
1036:
1003:
378:
J.P.M.G. Linnartz, "Performance
Analysis of Synchronous MC-CDMA in mobile Rayleigh channels with both Delay and Doppler spreads", IEEE VT, Vol. 50, No. 6, Nov. 2001, pp 1375–1387.
1026:
94:
A number of alternative possibilities exist as to how this frequency domain spreading can take place, such as by using a long PN code and multiplying each data symbol, d
776:
856:
819:
861:
627:
141:
guard interval is then added; and if transmission is in the downlink direction each of these resulting symbols are added together prior to transmission.
1021:
379:
1163:
738:
932:
402:
395:
769:
836:
806:
1041:
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524:
82:
implementation is to take N user bits (possibly but not necessarily for different destinations), to transform these using a Walsh
831:
1013:
975:
894:
814:
762:
518:
914:
608:
450:
45:-based telecommunication systems, allowing the system to support multiple users at the same time over same frequency band.
1031:
947:
871:
848:
479:
332:
175:
2-dimensional spreading in both the frequency and time domains is also possible, and a scheme that uses 2-D spreading is
712:
1142:
1137:
1129:
1046:
299:, an alternative multiple access scheme for OFDM systems, where the signals of different users are separated in the
1110:
603:
1105:
639:
420:
413:
History of Multi-Carrier Code
Division Multiple Access (MC-CDMA) and Multi-Carrier Spread Spectrum Workshop
1115:
130:
61:
1100:
789:
785:
530:
691:
1084:
571:
179:(which stands for variable spreading factor orthogonal frequency code-division multiplexing), which
824:
102:, or by using short PN codes and spreading each data symbol by an individual PN code — i.e. d
754:
681:
623:
443:
83:
269:
1079:
1051:
993:
797:
728:
391:
273:
17:
1066:
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665:
428:
300:
283:
282:
with both time and frequency spreading (Orthogonal
Frequency Code Division Multiple Access(
499:
494:
474:
459:
38:
322:
Broadband Packet
Wireless Access Based On VSF-OFCDM And MC/DS-CDMA (2002) Atarashi et al.
319:
1157:
707:
597:
436:
702:
634:
536:
249:
56:
One way of interpreting MC-CDMA is to regard it as a direct-sequence CDMA signal (
388:
Multi-Carrier and Spread
Spectrum Systems: From OFDM and MC-CDMA to LTE and WiMAX
686:
489:
340:
1074:
733:
411:
336:
229:
180:
164:. The symbol being modulated onto that carrier, for symbols 0 and 1, will be −
1056:
618:
191:
176:
988:
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651:
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884:
645:
613:
561:
236:
Gbit/s transmissions to receivers travelling at 10 km/h using its
149:
57:
60:), which is transmitted after it has been fed through an inverse FFT (
922:
879:
556:
410:
German Aerospace Center, Institute of Communications and Navigation,
998:
296:
279:
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259:
245:
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156:
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138:
134:
126:
122:
42:
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208:, of length 4, and a spreading factor in the frequency domain,
241:
237:
184:
419:
Wireless Communication Reference Web Site, section about
303:
by allocating different sub-carriers to different users.
121:
Once frequency domain spreading has taken place and the
240:
prototype system in a 100 MHz-wide channel. This
320:
http://citeseer.ist.psu.edu/atarashi02broadband.html
1128:
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965:
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590:
546:
508:
467:
98:, on a subcarrier by a chip from the PN code, c
770:
444:
201:, and a spreading factor in the time domain,
8:
390:, 2nd Edition, John Wiley & Sons, 2008,
125:subcarriers have all been allocated values,
27:Multiple access scheme in telecommunications
404:Multi Carrier Code Division Multiple Access
244:prototype system also uses a 12×12 antenna
31:Multi-carrier code-division multiple access
971:
802:
777:
763:
755:
451:
437:
429:
333:"DoCoMo Achieves 5 Gbit/s Data Speed"
194:works, if you take the first data symbol,
190:As an example of how the 2D spreading on
312:
110:and the resulting vector is placed on N
129:modulation then takes place using the
144:An alternative form of multi-carrier
7:
480:Code-division multiple access (CDMA)
262:with frequency spreading (MC-CDMA)
25:
525:Frequency-hopping spread spectrum
339:Press. 2007-02-09. Archived from
155:For the case of MC-DS-CDMA where
519:Direct-sequence spread spectrum
1:
1164:Code division multiple access
1094:Delay and disruption tolerant
252:for error correction coding.
18:Multi-carrier spread spectrum
713:Low probability of intercept
682:PN (pseudorandom noise) code
537:Time-hopping spread spectrum
215:of 2, then the data symbol,
1180:
721:
462:in digital communications
401:Hughes Software Systems,
739:Statistical multiplexing
386:K. Fazel and S. Kaiser,
226:symbols 0, 1, 2 and 3.
118:is the PN code length.
106:is multiplied by each c
86:, followed by an IFFT.
1116:Dynamic Source Routing
786:Channel access methods
697:Power spectral density
232:has already achieved 5
62:fast Fourier transform
729:Digital communication
591:Major implementations
531:Chirp spread spectrum
268:with time spreading (
790:media access control
114:subcarriers, where N
1014:Collision avoidance
248:configuration, and
976:Collision recovery
187:prototype system.
168:for symbol 0 and +
84:Hadamard transform
1151:
1150:
1130:Duplexing methods
1124:
1123:
961:
960:
752:
751:
396:978-0-470-99821-2
183:is using for its
16:(Redirected from
1171:
972:
803:
779:
772:
765:
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692:Near–far problem
509:Spread spectrum
453:
446:
439:
430:
416:, November 2006.
368:pp. 468–472
352:
351:
349:
348:
329:
323:
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301:frequency domain
235:
77:Downlink: MC-CDM
21:
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624:Cordless phones
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475:Spread spectrum
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460:Spread spectrum
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41:scheme used in
39:multiple access
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23:
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5:
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1067:Collision-free
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675:Major concepts
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495:Commercial use
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172:for symbol 1.
133:to produce an
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1005:
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989:Slotted ALOHA
987:
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799:
798:Channel-based
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745:
742:
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724:
723:
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709:
708:Rake receiver
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685:
683:
680:
679:
677:
673:
667:
664:
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656:
654:(aka IS-2000)
653:
650:
648:(aka cdmaOne)
647:
644:
641:
638:
636:
633:
632:
629:
625:
622:
620:
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598:Space Network
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468:Main articles
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454:
449:
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440:
435:
434:
431:
424:
423:
418:
415:
414:
409:
407:, March 2002.
406:
405:
400:
397:
393:
389:
385:
383:
382:
377:
374:
370:
366:
362:
361:
357:
343:on 2008-09-25
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74:
67:
65:
63:
59:
54:
50:
46:
44:
40:
36:
32:
19:
967:Packet-based
904:
703:Process gain
581:
548:
510:
421:
412:
403:
387:
380:
345:. Retrieved
341:the original
327:
315:
254:
250:turbo coding
228:
216:
209:
202:
195:
189:
174:
169:
165:
161:
154:
143:
137:symbol; the
120:
93:
80:
71:
55:
51:
47:
34:
30:
29:
490:Hedy Lamarr
1075:Token Ring
734:Modulation
358:Literature
347:2009-07-10
337:NTT DoCoMo
308:References
270:MC-DS-CDMA
230:NTT DoCoMo
181:NTT DoCoMo
1080:Token bus
1057:CSMA/CARP
619:Bluetooth
213:frequency
192:VSF-OFCDM
177:VSF-OFCDM
68:Rationale
1158:Category
1085:MS-ALOHA
890:TD-SCDMA
744:Waveform
725:See also
661:Qualcomm
652:CDMA2000
635:Cellular
567:TD-SCDMA
364:MC-CDMA)
291:See also
255:Summary
90:Variants
1037:CSMA/CA
1004:CSMA/CD
994:R-ALOHA
923:HC-SDMA
905:MC-CDMA
900:FH-CDMA
895:DS-CDMA
885:TD-CDMA
857:MF-TDMA
825:SC-FDMA
666:Verizon
614:GLONASS
609:Galileo
582:MC-CDMA
577:FH-CDMA
572:DS-CDMA
562:TD-CDMA
549:schemes
511:methods
500:More...
486:History
425:, 2001.
422:MC-CDMA
274:MT-CDMA
150:DS-CDMA
58:DS-CDMA
37:) is a
35:MC-CDMA
880:W-CDMA
642:Mobile
600:(NASA)
557:W-CDMA
539:(THSS)
527:(FHSS)
521:(DSSS)
394:
284:OFCDMA
234:
1106:VANET
1101:MANET
1027:MACAW
999:AX.25
984:ALOHA
862:STDMA
820:OFDMA
699:(PSD)
646:IS-95
640:EV-DO
547:CDMA
533:(CSS)
372:1993.
297:OFDMA
280:OFDMA
266:OFDMA
260:OFDMA
1032:CSMA
1022:MACA
948:PAMA
933:PDMA
915:SDMA
872:CDMA
849:TDMA
837:WDMA
807:FDMA
788:and
687:Chip
657:Also
628:DECT
392:ISBN
272:and
246:MIMO
224:OFDM
206:time
157:OFDM
146:CDMA
139:OFDM
135:OFDM
131:IFFT
127:OFDM
123:OFDM
116:freq
112:freq
43:OFDM
1143:FDD
1138:TDD
1111:DTN
1052:HCF
1047:PCF
1042:DCF
832:WDM
815:FDM
604:GPS
381:PDF
64:).
1160::
626::
335:.
286:))
242:4G
238:4G
210:SF
203:SF
185:4G
152:.
778:e
771:t
764:v
452:e
445:t
438:v
398:.
350:.
276:)
220:0
217:d
199:0
196:d
170:j
166:j
162:j
160:−
108:i
104:i
100:i
96:i
33:(
20:)
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