Interest of the Sequences Pseudo Noises Codes of Different Lengths for the Reduction from the Interference between Users of CDMA Network
The third generation (3G) of cellular system adopted
the spread spectrum as solution for the transmission of the data in the
physical layer. Contrary to systems IS-95 or CDMAOne (systems
with spread spectrum of the preceding generation), the new standard,
called Universal Mobil Telecommunications System (UMTS), uses
long codes in the down link. The system is conceived for the vocal
communication and the transmission of the data. In particular, the
down link is very important, because of the asymmetrical request of
the data, i.e., more remote loading towards the mobiles than towards
the basic station. Moreover, the UMTS uses for the down link an
orthogonal spreading out with a variable factor of spreading out
(OVSF for Orthogonal Variable Spreading Factor). This
characteristic makes it possible to increase the flow of data of one or
more users by reducing their factor of spreading out without
changing the factor of spreading out of other users. In the current
standard of the UMTS, two techniques to increase the performances
of the down link were proposed, the diversity of sending antenna and
the codes space-time. These two techniques fight only fainding. The
receiver proposed for the mobil station is the RAKE, but one can
imagine a receiver more sophisticated, able to reduce the interference
between users and the impact of the coloured noise and interferences
to narrow band. In this context, where the users have long codes
synchronized with variable factor of spreading out and ignorance by
the mobile of the other active codes/users, the use of the sequences of
code pseudo-noises different lengths is presented in the form of one
of the most appropriate solutions.
[1] Houda KHERDHER ? Mémoire pour grade de ma├«tre ès science : Effet
des codes correcteurs d-erreurs sur les systèmes CDMA ├á taux multiples,
Université Laval.
[2] Direct sequence spread spectrum sequences par Christophe Boulanger
(Sagem-Paris, Rue Watt, 75013 Paris), Gérard Loubet (INPG/LIS,
Campus Universitaire, 38402 St Martin D'heres), Jean René Lequepeys
(CEA-LETI, CEA GRENOBLE, Rua des Martyrs, 38054 GRENOBLE)
et Laurent Ouvry CEA-LETI, Cea Grenoble, Rua des Martyrs, 38054
Grenoble).
[3] Statistique d-ordre supérieur pour le traitement du signal, J.L.Lacoume,
P.O.Ambland, P.Comon, (Masson, paris, 1997).
[4] Pursley, M.B., "Performance Evaluation for Phase-coded Spread-
Spectrum Multiple-Acces Communication. Part 1: System Analysis".
IEEE Transactions on Communications, Vol 1. COM-25. No. 8, pp. 795-
799, Ao├╣t 1977.
[5] Pursley, M.B. et Sarwate, D.V., "Performance Evaluation for Phasecoded
Spread-Spectrum Multiple-Acces Comrnunication. Part 2: Code
Sequence Analysis". IEEE Transactions on Communications, Vol.
COM-25, No. 8, pp. 800-803, Ao├╣t 1977.
[6] Pursley, M.B. et ROEFS, H.F.A., "Numerical Evaluation of Correlation
Parameters for Optimal Phases of Binary Shift-Register Sequences".
IEEE Transactions on Communications, Vol. COM-27, NO. 10, pp.
1597- 1604, October 1979.
[7] Ottosson, T. et Svensson, A., "Multi-Rate Schemes in DS/CDMA
Systems". Proc. IEEE VTC'95, Chicago, Juillet 1995.
[8] Analyse des systèmes linéaires (chapitre 1 ├á 4) Jean COAT et Jean-
Marie Escane.
[1] Houda KHERDHER ? Mémoire pour grade de ma├«tre ès science : Effet
des codes correcteurs d-erreurs sur les systèmes CDMA ├á taux multiples,
Université Laval.
[2] Direct sequence spread spectrum sequences par Christophe Boulanger
(Sagem-Paris, Rue Watt, 75013 Paris), Gérard Loubet (INPG/LIS,
Campus Universitaire, 38402 St Martin D'heres), Jean René Lequepeys
(CEA-LETI, CEA GRENOBLE, Rua des Martyrs, 38054 GRENOBLE)
et Laurent Ouvry CEA-LETI, Cea Grenoble, Rua des Martyrs, 38054
Grenoble).
[3] Statistique d-ordre supérieur pour le traitement du signal, J.L.Lacoume,
P.O.Ambland, P.Comon, (Masson, paris, 1997).
[4] Pursley, M.B., "Performance Evaluation for Phase-coded Spread-
Spectrum Multiple-Acces Communication. Part 1: System Analysis".
IEEE Transactions on Communications, Vol 1. COM-25. No. 8, pp. 795-
799, Ao├╣t 1977.
[5] Pursley, M.B. et Sarwate, D.V., "Performance Evaluation for Phasecoded
Spread-Spectrum Multiple-Acces Comrnunication. Part 2: Code
Sequence Analysis". IEEE Transactions on Communications, Vol.
COM-25, No. 8, pp. 800-803, Ao├╣t 1977.
[6] Pursley, M.B. et ROEFS, H.F.A., "Numerical Evaluation of Correlation
Parameters for Optimal Phases of Binary Shift-Register Sequences".
IEEE Transactions on Communications, Vol. COM-27, NO. 10, pp.
1597- 1604, October 1979.
[7] Ottosson, T. et Svensson, A., "Multi-Rate Schemes in DS/CDMA
Systems". Proc. IEEE VTC'95, Chicago, Juillet 1995.
[8] Analyse des systèmes linéaires (chapitre 1 ├á 4) Jean COAT et Jean-
Marie Escane.
@article{"International Journal of Electrical, Electronic and Communication Sciences:52249", author = "Nerguè Kassahan Kone and Souleymane Oumtanaga", title = "Interest of the Sequences Pseudo Noises Codes of Different Lengths for the Reduction from the Interference between Users of CDMA Network", abstract = "The third generation (3G) of cellular system adopted
the spread spectrum as solution for the transmission of the data in the
physical layer. Contrary to systems IS-95 or CDMAOne (systems
with spread spectrum of the preceding generation), the new standard,
called Universal Mobil Telecommunications System (UMTS), uses
long codes in the down link. The system is conceived for the vocal
communication and the transmission of the data. In particular, the
down link is very important, because of the asymmetrical request of
the data, i.e., more remote loading towards the mobiles than towards
the basic station. Moreover, the UMTS uses for the down link an
orthogonal spreading out with a variable factor of spreading out
(OVSF for Orthogonal Variable Spreading Factor). This
characteristic makes it possible to increase the flow of data of one or
more users by reducing their factor of spreading out without
changing the factor of spreading out of other users. In the current
standard of the UMTS, two techniques to increase the performances
of the down link were proposed, the diversity of sending antenna and
the codes space-time. These two techniques fight only fainding. The
receiver proposed for the mobil station is the RAKE, but one can
imagine a receiver more sophisticated, able to reduce the interference
between users and the impact of the coloured noise and interferences
to narrow band. In this context, where the users have long codes
synchronized with variable factor of spreading out and ignorance by
the mobile of the other active codes/users, the use of the sequences of
code pseudo-noises different lengths is presented in the form of one
of the most appropriate solutions.", keywords = "DS-CDMA, multiple access interference, ratio
Signal / interference + Noise.", volume = "2", number = "11", pages = "2476-4", }