Résumé
Cet article développe les structures des récepteurs en râteau à temps continu et à temps discret. Le premier récepteur est celui qu’on utilise ďhabitude et consiste à combiner les sorties de corrélateurs synchronisés sur les trajets les plus significatifs. Afin de pallier ľincapacité des dispositifs de synchronisation usuels à discerner des trajets à instants ľarrivée proches, nous proposons un algorithme ľacquisition au maximum de vraisemblance ainsi qu’ une boucle de poursuite améliorée. Le second récepteur, récemment proposé, fonctionne sans aucune connaissance du nombre de trajets et de leurs délais. Il est basé sur une estimation globale du produit de convolution des réponses impulsionnelles du canal de propagation et du filtre de mise en forme. La comparaison des performances des deux récepteurs est établie dans le cadre applicatif du mode fdd de la norme UMTS.
Abstract
This paper investigates the structure of a continuous and a discrete time Rake receivers. The former receiver is the most used and consists on combining the output of correlators locked on the most significant paths. Since the conventional synchronisation module of this receiver is not able to distinguish closer paths, we propose a maximum likelihood acquisition algorithm and an enhanced tracking loop. The latter receiver was recently suggested and works without the knowledge of path delays and their number. It is based on a global estimation of the impulse response of the multipath channel convolutionned with the shaping filter. Performance comparison of the two receivers is established for the fdd mode of the umts interface.
This is a preview of subscription content, log in via an institution to check access.
Bibliographie
Proakis (J.G.), Digital communications,Mc Graw-Hill (1995).
Viterbi (A.J.), Principle of spread spectrum multiple access communications,Qualcomm (1994).
Zhang (Q.),Huang (J.),Xie (Y.), High resolution delay estimation,Proceeding TENCON (1993), pp. 579–583.
Van Nee (R.D.J.), The multipath estimating delay lock loop,International Symposium on Spread Spectrum Techniques and Applications (Décembre 1992), pp. 39–42.
Boujemâa (H.),Siala (M.), On a maximum likelihood delay acquisition algorithm,International Conference on Communications (Juin 2001), Helsinki.
Boujemâa (H.), Siala (M.), Enhanced coherent delay tracking for Direct Sequence Spread Spectrum Systems,International Symposium on Spread Spectrum Techniques and Applications (Septembre 2000), Vol 1, pp. 274–277, New Jersey.
Boujemâa (H.), Fratu (O.), Siala (M.), Loubaton (P.), On the performance of a Discrete Time Rake,Personal, Indoor and Mobile Radio Communications (Septembre 2000), Vol 2, pp. 949–953, Londres.
3gpp TSG ran #5 (99)587, October 1999, ts 25.211 v3.0.0 (1999- 10), Physical channels and mapping of transport channels onto physical channels (fdd).
Boujemâa (H.), Siala (M.), On the Rake receiver performance,Vehicular Technology Conference Fall (Septembre 2000), Vol 3, pp. 1483–1488, Boston.
Visoz (R.),Bejjani (E.),Kumar (V.), Matched Filter Bound for Equalization and Antenna Diversity over Mobile Radio channels,International Conference on Universal Personal Communications (Octobre 1998), pp. 573–578, Florence.
Sourrour (E.), Bottomley (G.), Ramesh (R.), Delay tracking for direct sequence spread spectrum systems in multipath fading channels,Vehicular Technology Conference Spring (Mai 1999), Vol 1, pp. 422–426, Amsterdam.
Siala (M.), Duponteil (D.), Iterative Rake receiver with map channel estimation for ds-cdma systems,Vehicular Technology Conference Spring (1999), Vol 2, pp. 1121–1125, Amsterdam.
Van Trees (H.L.), Detection, estimation, and modulation theory, Part 1: detection, estimation, and linear modulation theory,Wiley J. (1968).
de Gaudenzi (R.), Luise (M.), Decision directed coherent delay- lock tracking loop for DS-Spread-Spectrum signals,IEEE Trans, on Comm. (1991), Vol 39, pp. 758–765.
Boujemâa (H.), Siala (M.), Performance of coherent and non coherent dix in awgn channel,Personal, Indoor and Mobile Radio Communications (Septembre 2000), Vol 1, pp. 147–150, Londres.
Sheen (W.H.), Stuber (G.L.), Effects of multipath fading on delay locked loops for spread spectrum systems,IEEE Trans, on Comm. (1994), Vol 42, pp. 1947–1956.
Bogush (R.L.), Giugliano (F.W.), Knepp (D.L.), Michelet (A.H.), Frequency selective propagations effects on spread spectrum receiver tracking,Proceding of the IEEE (1981), Vol 69, pp. 787–796.
Ding (Z.), Multipath channel identification based on partial system information,IEEE Trans, on Signal Processing (1997), Vol 45, n. 1, pp. 235–240.
Tidestav (C.),Lindskog (E.), Bootstrap equalisation,International Conference on Universal Personal Communications (Octobre 1998), pp. 1221–1225, Florence.
Sheen (W.H.), Stuber (G.L.), A new tracking loop for spread spectrum systems on frequency-selective fading channels,IEEE Trans, on Comm., Vol com-43, pp. 3063–3072, Décembre 1995.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
BoujemÂa, H., Siala, M. Récepteurs en râteau pour les systèmes à étalement de spectre par séquences directes. Ann. Télécommun. 56, 291–305 (2001). https://doi.org/10.1007/BF03001332
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF03001332
Mots clés
- Spectre étalé séquence directe
- Récepteur optimal
- Circuit multicanal
- Systàme continu
- Systàme discret
- Estimation paramàtre
- Canal radioélectrique
- Propagation trajet multiple
- Filtre adapté
- Maximum vraisemblance
- Acquisition signal
- Poursuite
- Boucle verrouillage