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[CR12] Multi-user adaptive receivers for a Multiple-Access System based on Random Permutations on Time-Varying Frequency-Selective Channels with Unknown Delays and CoefficientsRevue Internationale avec comité de lecture : Journal IET Communications , 2012
motcle:
Résumé:
This paper deals with a multiple-access transmission scheme based on random per-
mutations, which allows one to obtain both spectrum spreading and time spreading.
In particular, one is interested by the multi-user detection when the transmission
is achieved in the context of asynchronous frequency-selective and time-varying
channels. For this detection, it is assumed that the channel coecients and delays
are unknown at the receiver side. Instead, only rough estimates of the minimum
and maximum delays are available. However, it is supposed that the transmitter
sends pilot signals, i.e. training bit sequences, which allow the receiver to perform
an LMS-type detection. This paper provides theoretical performance results. More-
over, this random permutation-based transmission scheme is compared with the
DS-CDMA system, for which a similar LMS receiver is dened, under the same as-
sumptions. It is then shown that, for time-varying channels, the permutation-based
system presents lower bit-error-rates than the DS-CDMA system, since the former
provides time diversity.
Equipe:
laetitia
Collaboration:
ENSEEIHT
BibTeX
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