EP1869798A1 - Device and method for increasing the robustness or the capacity of wireless communication systems - Google Patents

Device and method for increasing the robustness or the capacity of wireless communication systems

Info

Publication number
EP1869798A1
EP1869798A1 EP06725501A EP06725501A EP1869798A1 EP 1869798 A1 EP1869798 A1 EP 1869798A1 EP 06725501 A EP06725501 A EP 06725501A EP 06725501 A EP06725501 A EP 06725501A EP 1869798 A1 EP1869798 A1 EP 1869798A1
Authority
EP
European Patent Office
Prior art keywords
users
user
frequency
increasing
capacity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06725501A
Other languages
German (de)
French (fr)
Inventor
Marc Chenu-Tournier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thales SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thales SA filed Critical Thales SA
Publication of EP1869798A1 publication Critical patent/EP1869798A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0667—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/12—Frequency diversity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/068—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission using space frequency diversity

Definitions

  • the invention particularly relates to a method and a device for increasing the capacity of wireless telecommunications systems, in particular by providing diversity to a reception system.
  • diversity is understood as the ability to use multiple copies of the same transmitted signal. Each copy has been degraded or distorted (channel or interference) independent.
  • the reception diversity notably makes it possible to greatly increase the performance of the receiver and therefore the robustness or the capacity of the telecommunications link.
  • reception and / or emission sensor networks is an effective means when the processing adapted to the transmission and / or reception is implemented.
  • the invention is based in particular on a new approach by transmitting simultaneously through several propagation channels, the superposition of the messages to be transmitted.
  • the invention relates to a method for increasing the capacity of a wireless communications system comprising at least two users Ui and U 2 communicating by means of at least one frequency band Fi, F 2, characterized in that the flow of information Si (t) of the first user Ui and the information flow s 2 (t) of the second user U 2 are traveling in at least one and the same frequency band.
  • the method according to the invention makes it possible in particular to increase the performance of the demodulation in a system compared to the conventional system, a band, a flow.
  • One of the advantages of the present invention is that it allows the receiver to benefit from additional diversity compared to the conventional case where each transmitter exclusively uses the frequency band which has been dedicated to it.
  • FIG. 1 is a schematic diagram of the method according to the invention
  • FIG. 2 schematizes a device architecture for implementing the invention
  • Figure 1 shows schematically the steps implemented in the case of a system using two frequencies. This can be extended to any system including a number of frequencies and users greater than 2.
  • the system represented in FIG. 2 comprises several users Ui emitting information flows across several frequency bands, a receiver R comprising in particular a processor P adapted to implement the steps of the method according to the invention.
  • the user Ui transmits in a frequency band Fi and the user U 2 in a frequency band F 2 .
  • the method includes transmitting the flows Si (t) and s 2 (t) of each of the users on each of the frequency bands.
  • the sum of the two information flows or flows of interest coming from the two users propagates.
  • a user transmits with a power 2 times lower, which helps to reduce the transmission power to avoid increasing the power transmitted in a cell.
  • the signals received by the receiver express themselves:
  • each transmitter emits with a lower power than it uses in the case a band, a frequency.
  • One of the interests of the process is to bring what the skilled person calls diversity to the receiver. In the case of multi-path degraded transmission channels, this diversity can improve the performance of reception systems without consuming more bandwidth or increasing power.
  • the method according to the invention also applies for downlinks. For example, when it is desired to transmit to several users from an access point, it is possible to bring diversity to the receiver.
  • the system comprises three users referenced by their signals Si, S 2 , S 3 to which it is desired to transmit information and three frequencies, on each frequency F 1 , F 2 and F 3 , a pair of signals ⁇ si, s 2 ) or ⁇ si, s 3 ) or ⁇ s 2 , s 3 ) is transmitted.
  • the demodulation can be simplified when the number of users simultaneously using the same frequency band is not too high.
  • a receiver type RAKE filter adapted to the channel and the code
  • the method also applies to another type of access, by modulation.
  • a downlink rather than using a frequency or time slot to transmit streams to a user, it is possible to share a multilevel modulation between different users.
  • the dedicated stream is transmitted on the real part for, for example, the even bits and the imaginary part are dedicated to another user.
  • one of the axes serves to transmit the odd bits of the first user and the other axis serves the second user.
  • fewer channels are used than users.
  • the choice of channels to use is based on their statistical independence.
  • FIG. 2 represents performance curves obtained by implementing the method according to the invention.
  • the simulation parameters used are:
  • the system uses Orthogonal frequency-division multiplexing (OFDM) modulation with a multiple access system that is either frequency or time.
  • OFDM Orthogonal frequency-division multiplexing
  • different transmitters can share this resource by simultaneously communicating with the constraint that the receiving system embeds the method of separation of multiple streams.
  • the method has been implemented for an OFDM modulation using 64 subcarrier, of which only 52 are used to transmit data.
  • the system uses an OFDM modulation with a multiple access system either frequency or time.
  • different transmitters can share this resource by simultaneously communicating with the constraint that the receiving system embeds the method of separation of multiple streams.
  • the performances of the process are simulated and compared to a process which does not use the principle of the invention where the process is not implemented.
  • This study focuses on the upstream link and the technique to separate the different flows of different users is a maximum likelihood algorithm with flexible output.
  • the modulation used is a BSPK
  • the propagation channels are assumed to be known and independent between the users and the resources (time or frequency).
  • the parameters of the waveform are those of the 802.11a standard whose aspects of corrective coding.
  • the transmitted total powers remain constant whatever the transmission method used in order to obtain relevant comparisons.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Transmission System (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The invention relates to a method of increasing the capacity of a wireless communication system comprising at least two users, U1 and U2, communicating by means of at least one frequency band F1, F2. The invention is characterised in that the information stream s1(t) from the first user U1 and the information stream s2(t) from the second user are transmitted in at least one identical frequency band.

Description

DISPOSITIF ET PROCEDE POUR ACCROITRE LA ROBUSTESSE OU LA CAPACITE DES SYSTEMES DE COMMUNICATION SANS FILDEVICE AND METHOD FOR INCREASING THE ROBUSTNESS OR CAPACITY OF WIRELESS COMMUNICATION SYSTEMS
L'invention concerne notamment un procédé et un dispositif permettant d'accroître la capacité des systèmes de télécommunications sans fil, notamment en apportant de la diversité à un système de réception.The invention particularly relates to a method and a device for increasing the capacity of wireless telecommunications systems, in particular by providing diversity to a reception system.
Dans la description, la diversité s'entend comme la capacité à utiliser plusieurs copies d'un même signal émis. Chaque copie a subi des dégradations ou des distorsions (canal ou interférences) indépendantes.In the description, diversity is understood as the ability to use multiple copies of the same transmitted signal. Each copy has been degraded or distorted (channel or interference) independent.
Dans les canaux de propagation à évanouissements ou subissant des interférences, la diversité de réception permet notamment d'accroître grandement les performances du récepteur et donc la robustesse ou la capacité du lien de télécommunications.In the fading or interference propagation channels, the reception diversity notably makes it possible to greatly increase the performance of the receiver and therefore the robustness or the capacity of the telecommunications link.
Pour apporter de la diversité au lien de télécommunication, l'utilisation de réseaux de capteurs à la réception et/ou à l'émission est un moyen efficace lorsque les traitements adaptés à l'émission et/ou à la réception sont mis en œuvre.In order to bring diversity to the telecommunication link, the use of reception and / or emission sensor networks is an effective means when the processing adapted to the transmission and / or reception is implemented.
Un des inconvénients de ces méthodes est qu'elles nécessitent l'utilisation de plusieurs voies de réception ou d'émission.One of the disadvantages of these methods is that they require the use of several reception or transmission channels.
Un procédé connu de l'art antérieur décrit par exemple dans le livre de Proakis, Digital Communication, chapitre 8, 4ΘmΘ édition, Mc Graw- HiII, utilise la diversité fréquentielle ou temporelle du canal de propagation au moyen d'un système de « codage canal ». Les informations utiles sont d'abord traitées pour introduire de la redondance. Ces informations codées sont ensuite transmises au travers de canaux de propagations différents afin d'apporter de la diversité au décodeur. L'invention repose notamment sur une nouvelle approche en transmettant simultanément au travers de plusieurs canaux de propagations, la superposition des messages à transmettre. L'invention concerne un procédé pour accroître la capacité d'un système de communications sans fil comprenant au moins deux utilisateurs Ui et U2 communiquant au moyen d'au moins une bande de fréquence F-i , F2 caractérisé en ce que le flux d'informations Si(t) du premier utilisateur Ui et le flux d'informations s2(t) du deuxième utilisateur U2 circulent dans au moins une même bande de fréquence.A known method of the prior art described, for example in the book of Proakis, Digital Communication, Chapter 8, 4 ΘmΘ edition, Mc Graw- HiII, uses the frequency diversity or time of the propagation channel by means of a system of " channel coding ". Useful information is first processed to introduce redundancy. This coded information is then transmitted through different propagation channels in order to bring diversity to the decoder. The invention is based in particular on a new approach by transmitting simultaneously through several propagation channels, the superposition of the messages to be transmitted. The invention relates to a method for increasing the capacity of a wireless communications system comprising at least two users Ui and U 2 communicating by means of at least one frequency band Fi, F 2, characterized in that the flow of information Si (t) of the first user Ui and the information flow s 2 (t) of the second user U 2 are traveling in at least one and the same frequency band.
Le procédé selon l'invention permet notamment d'augmenter les performances de la démodulation dans un système par rapport au système classique, une bande, un flux. Un des intérêts de la présente invention est qu'elle permet de faire bénéficier le récepteur d'une diversité supplémentaire comparé au cas classique où chaque émetteur utilise de façon exclusive la bande de fréquence qui lui a été dédiée.The method according to the invention makes it possible in particular to increase the performance of the demodulation in a system compared to the conventional system, a band, a flow. One of the advantages of the present invention is that it allows the receiver to benefit from additional diversity compared to the conventional case where each transmitter exclusively uses the frequency band which has been dedicated to it.
D'autres caractéristiques et avantages de la présente invention apparaîtront mieux à la lecture de la description qui suit d'un exemple de réalisation donnée à titre illustratif et nullement limitatif, annexé des figures qui représentent :Other features and advantages of the present invention will emerge more clearly on reading the following description of an exemplary embodiment given by way of illustration and in no way limiting, appended to the figures which represent:
• La figure 1 un schéma de principe du procédé selon l'invention, • La figure 2 schématise une architecture de dispositif permettant de mettre en œuvre l'invention,FIG. 1 is a schematic diagram of the method according to the invention, FIG. 2 schematizes a device architecture for implementing the invention,
• La figure 3 des résultats des performances obtenues en mettant en œuvre l'invention.• Figure 3 performance results obtained by implementing the invention.
La figure 1 schématise les étapes mises en œuvre dans le cas d'un système utilisant deux fréquences. Ceci peut s'étendre à tout système comprenant un nombre de fréquences et d'utilisateurs supérieur à 2.Figure 1 shows schematically the steps implemented in the case of a system using two frequencies. This can be extended to any system including a number of frequencies and users greater than 2.
Le système représenté à la figure 2 comprend plusieurs utilisateurs Ui émettant des flux d'informations à travers plusieurs bandes de fréquences, un récepteur R comprenant notamment un processeur P adapté à mettre en œuvre les étapes du procédé selon l'invention. L'utilisateur Ui émet dans une bande de fréquence Fi et l'utilisateur U2 dans une bande de fréquence F2. Le procédé consiste notamment à transmettre les flux Si(t) et s2(t) de chacun des utilisateurs sur chacune des bandes de fréquence. Ainsi, sur chaque bande de fréquence la somme des deux flux informatifs ou flux d'intérêts provenant des deux utilisateurs se propage.The system represented in FIG. 2 comprises several users Ui emitting information flows across several frequency bands, a receiver R comprising in particular a processor P adapted to implement the steps of the method according to the invention. The user Ui transmits in a frequency band Fi and the user U 2 in a frequency band F 2 . The method includes transmitting the flows Si (t) and s 2 (t) of each of the users on each of the frequency bands. Thus, on each frequency band, the sum of the two information flows or flows of interest coming from the two users propagates.
Dans le cas de deux utilisateurs, dans chaque bande, un utilisateur transmet avec une puissance 2 fois plus faible, ce qui contribue à diminuer la puissance d'émission pour éviter d'accroître la puissance transmise dans une cellule.In the case of two users, in each band, a user transmits with a power 2 times lower, which helps to reduce the transmission power to avoid increasing the power transmitted in a cell.
En notant Si(t) le premier flux et s2(t) le second flux correspondant respectivement aux utilisateurs Ui et U2 et en considérant que la perturbation apportée par le canal de propagation est composée d'un bruit additif gaussien bu(t) avec 1 ≤ u≤2 et d'une atténuation αι υ , par exemple suivant une loi de Rayleigh, avec la fréquence / vérifiant 1 </< 2 et l'indice des utilisateurs u vérifiant ~\ ≤ u≤2, les signaux reçus par le récepteur s'expriment :Noting Si (t) the first stream and s 2 (t) the second stream respectively corresponding to users Ui and U 2 and considering that the disturbance provided by the propagation channel is composed of a Gaussian additive noise b u (t ) with 1 ≤ u≤2 and with an attenuation α ι υ , for example according to a Rayleigh law, with the frequency / satisfying 1 </ <2 and the index of the users u verifying ~ \ ≤ u≤2, the signals received by the receiver express themselves:
Z1 (t) = CtIs1 (0 + a\s2 (0 + bx (0 Z2 (t) = al S1 (0 + Or2 2S2 (t) + b2 (0Z 1 (t) = CtIs 1 (0 + a \ s 2 (0 + b x (0 Z 2 (t) = al S 1 (0 + Or 2 2 S 2 (t) + b 2 (0
Ces observations peuvent s'écrire sous la forme matricielle suivante :These observations can be written in the following matrix form:
A partir de ce modèle de signal, les techniques de détection conjointe et d'égalisation connues de l'Homme du métier peuvent être appliquées sur les observations pour estimer les signaux utiles transmis vers un point d'accès. Selon un mode de réalisation, chaque émetteur émet avec une puissance inférieure à celle qu'il utilise dans le cas une bande, une fréquence. L'un des intérêts du procédé est d'apporter ce que l'homme de métier appelle de la diversité au récepteur. Dans le cas de canaux de transmissions dégradés par des trajets multiples cette diversité permet d'améliorer les performances des systèmes de réceptions sans consommer plus de bande ni augmenter la puissance.From this signal model, the joint detection and equalization techniques known to those skilled in the art can be applied to the observations to estimate the useful signals transmitted to an access point. According to one embodiment, each transmitter emits with a lower power than it uses in the case a band, a frequency. One of the interests of the process is to bring what the skilled person calls diversity to the receiver. In the case of multi-path degraded transmission channels, this diversity can improve the performance of reception systems without consuming more bandwidth or increasing power.
L'enseignement technique explicité ci-dessus s'applique pour une liaison montante de plusieurs utilisateurs vers un point d'accès utilisant plusieurs fréquences, ou accès multiple par répartitions de fréquences.The technical teaching explained above applies for an uplink of several users to an access point using several frequencies, or multiple access by frequency distributions.
Il s'applique aussi dans le domaine temporel, accès multiple à répartition dans le temps, ou même avec un accès multiple à répartitions par code. Le procédé selon l'invention s'applique aussi pour des liens descendants. Par exemple lorsque l'on souhaite transmettre vers plusieurs utilisateurs depuis un point d'accès, il est possible d'apporter de la diversité au récepteur.It is also applicable in the time domain, time division multiple access, or even code division multiple access. The method according to the invention also applies for downlinks. For example, when it is desired to transmit to several users from an access point, it is possible to bring diversity to the receiver.
Dans le cas où le système comporte trois utilisateurs référencés par leurs signaux Si, S2, S3 vers qui on souhaite transmettre des informations et trois fréquences, sur chaque fréquence F1, F2 et F3, un couple de signaux {si,s2) ou {si,s3) ou {s2,s3) est transmis.In the case where the system comprises three users referenced by their signals Si, S 2 , S 3 to which it is desired to transmit information and three frequencies, on each frequency F 1 , F 2 and F 3 , a pair of signals {si, s 2 ) or {si, s 3 ) or {s 2 , s 3 ) is transmitted.
Dans le cas simple d'un canal composé d'un affaiblissement de Rayleigh et d'un bruit additif, les observations exploitables par le récepteur sont :In the simple case of a channel composed of a Rayleigh weakening and an additive noise, the observations exploitable by the receiver are:
Z1 (t) = O1(S1(O + S2 (O) + ^i (OZ 1 (t) = O 1 (S 1 (O + S 2 (O) +
Z2 (0 = «2 (S1 (0 + S3 (0) + b2 (0 Z3 (0 = «3 (s2 (0 + S3 (0) + b3 (0Z 2 (0 = 2 (S 1 (0 + S 3 (0) + b 2 (0 Z 3 (0 = 3 (s 2 (0 + S 3 (0) + b 3 (0
Avec ces observations, le procédé construit les signaux suivants, comme premier traitement au niveau du récepteur : *) = *-> +*-> - ,(0With these observations, the method constructs the following signals as the first processing at the receiver: *) = * -> + * -> -, (0
«, «2 a,«,« 2 a,
= 2.^(0 + - fe (0 -+ fc^(0 — fe,(0= 2. ^ (0 + - fe (0 - + fc ^ (0 - fe , (0
«, α,", Α,
ou encoreor
II est ensuite possible d'appliquer les techniques de détection conjointe connues de l'Homme du métier sur ces observations pour déterminer ou estimer les signaux ou les symboles qui ont été transmis.It is then possible to apply the joint detection techniques known to those skilled in the art to these observations to determine or estimate the signals or symbols that have been transmitted.
Dans le cas de la liaison descendante, en utilisant le procédé avec des techniques à étalement de spectre, la démodulation peut être simplifiée lorsque le nombre d'utilisateurs utilisant simultanément la même bande de fréquence n'est pas trop élevée. Dans ce cas, un récepteur de type RAKE (filtre adapté au canal et au code) suffit et donc, l'utilisation de deux bandes pour apporter suffisamment de diversité.In the case of the downlink, using the method with spread spectrum techniques, the demodulation can be simplified when the number of users simultaneously using the same frequency band is not too high. In this case, a receiver type RAKE (filter adapted to the channel and the code) is sufficient and therefore, the use of two bands to provide enough diversity.
Sans sortir du cadre de l'invention, le procédé s'applique aussi à un autre type d'accès, par modulation.Without departing from the scope of the invention, the method also applies to another type of access, by modulation.
Dans une liaison descendante, plutôt que d'utiliser une fréquence ou slot temporel pour transmettre des flux vers un utilisateur, il est possible de partager une modulation multiniveaux entre différents utilisateurs.In a downlink, rather than using a frequency or time slot to transmit streams to a user, it is possible to share a multilevel modulation between different users.
Dans le cas de deux utilisateurs utilisant une modulation QPSK (Quadrature Phase Shift Keying), sur une fréquence, le flux qui lui est dédié est transmis sur la partie réelle pour, par exemple, les bits pairs et la partie imaginaire sont dédiés à un autre utilisateur. De même sur une autre fréquence, un des axes sert à transmettre les bits impairs du premier utilisateur et l'autre axe sert au second utilisateur.In the case of two users using Quadrature Phase Shift Keying (QPSK), on a frequency, the dedicated stream is transmitted on the real part for, for example, the even bits and the imaginary part are dedicated to another user. Likewise on another frequency, one of the axes serves to transmit the odd bits of the first user and the other axis serves the second user.
Selon une variante de réalisation, dans le cas d'une liaison montante, on utilise moins de canaux que d'utilisateurs. Le choix des canaux à utiliser repose sur leur indépendance statistique.According to an alternative embodiment, in the case of an uplink, fewer channels are used than users. The choice of channels to use is based on their statistical independence.
Dans ce cas, il est possible en utilisant les informations issues du décodeur en combinaison avec un récepteur itératif de démoduler les différents flux informatifs transmis, selon un procédé connu par l'Homme du métier. Ceci peut être le procédé décrit dans la demande de brevet FRIn this case, it is possible by using the information from the decoder in combination with an iterative receiver to demodulate the various information streams transmitted, according to a method known to those skilled in the art. This can be the process described in the FR patent application
03/14014 du demandeur.03/14014 of the applicant.
La figure 2 représente des courbes de performances obtenues par la mise en œuvre du procédé selon l'invention. Les paramètres de simulation utilisés sont :FIG. 2 represents performance curves obtained by implementing the method according to the invention. The simulation parameters used are:
• Le nombre d'émetteurs (# users),• The number of transmitters (# users),
• Le nombre de canaux utilisés (# Rx égal au nombre d'émetteurs #Rx=#users),• The number of channels used (# Rx equal to the number of transmitters # Rx = # users),
• Le nombre de trajets indépendants par canal de propagation (#paths). Ce dernier paramètre est intéressant en ce sans que le procédé exploite l'apport de diversité pour séparer les différents flux. On remarque que le gain d'un tel procédé est supérieur dans le cas où l'ordre de diversité est faible. En effet, c'est dans ces conditions que l'accroissement de l'ordre de diversité a le plus d'impact sur les performances.• The number of independent paths per propagation channel (#paths). This last parameter is interesting in this without the process exploits the contribution of diversity to separate the different flows. Note that the gain of such a method is greater in the case where the order of diversity is low. In fact, it is in these conditions that increasing the order of diversity has the greatest impact on performance.
Dans cet exemple, le système exploite une modulation OFDM (Orthogonal frequency-division multiplexing) avec un système d'accès multiple soit fréquentiel, soit temporel. Ainsi différents transmetteurs peuvent se partager cette ressource en communiquant simultanément avec comme contrainte que le système de réception embarque le procédé de séparation des flux multiples. Dans ce contexte, le procédé a été mis en oeuvre pour une modulation OFDM utilisant 64 sous-porteuse, dont seulement 52 sont utilisées pour transmettre des données.In this example, the system uses Orthogonal frequency-division multiplexing (OFDM) modulation with a multiple access system that is either frequency or time. Thus different transmitters can share this resource by simultaneously communicating with the constraint that the receiving system embeds the method of separation of multiple streams. In this context, the method has been implemented for an OFDM modulation using 64 subcarrier, of which only 52 are used to transmit data.
Dans cet exemple d'application, le système exploite une modulation OFDM avec un système d'accès multiple soit fréquentiel soit temporel. Ainsi, différents transmetteurs peuvent se partager cette ressource en communiquant simultanément avec comme contrainte que le système de réception embarque le procédé de séparation des flux multiples.In this application example, the system uses an OFDM modulation with a multiple access system either frequency or time. Thus, different transmitters can share this resource by simultaneously communicating with the constraint that the receiving system embeds the method of separation of multiple streams.
Dans cette étude comparative les performances du procédé sont simulées et comparées à un procédé qui n'utilise pas le principe de l'invention cas ou le procédé n'est pas mis en œuvre. Cette étude se focalise sur le lien montant et la technique pour séparer les différents flux des différents utilisateurs est un algorithme du maximum de vraisemblance à sortie souple. La modulation utilisée est une BSPK, les canaux de propagations sont supposés connus et indépendants entre les utilisateurs et les ressources (temporelles ou fréquentielles). Les paramètres de la forme d'onde reprennent ceux du standard 802.11 a dont les aspects de codage correcteur. Dans l'exemple donné les puissances totales transmises restent constantes quel que soit le procédé de transmission utilisé afin d'obtenir des comparaisons pertinentes. In this comparative study the performances of the process are simulated and compared to a process which does not use the principle of the invention where the process is not implemented. This study focuses on the upstream link and the technique to separate the different flows of different users is a maximum likelihood algorithm with flexible output. The modulation used is a BSPK, the propagation channels are assumed to be known and independent between the users and the resources (time or frequency). The parameters of the waveform are those of the 802.11a standard whose aspects of corrective coding. In the example given, the transmitted total powers remain constant whatever the transmission method used in order to obtain relevant comparisons.

Claims

REVENDICATIONS
1 - Procédé pour accroître la capacité d'un système de communications sans fil comprenant au moins deux utilisateurs Ui et U2 communiquant au moyen d'au moins une bande de fréquence F1, F2, caractérisé en ce que le flux d'informations Si(t) du premier utilisateur Ui et le flux d'informations s2(t) du deuxième utilisateur U2 circulent dans au moins une même bande de fréquence.1 - Method for increasing the capacity of a wireless communication system comprising at least two users Ui and U 2 communicating by means of at least one frequency band F 1 , F 2 , characterized in that the information flow If (t) the first user Ui and the information flow s 2 (t) of the second user U 2 are traveling in at least one and the same frequency band.
2 - Procédé selon la revendication 1 , caractérisé en ce que l'on transmet les deux flux si(t) et s2(t) de chacun des utilisateurs sur chacune des deux bandes de fréquence Fi et F2.2 - Process according to claim 1, characterized in that one transmits the two flows si (t) and s 2 (t) of each of the users on each of the two frequency bands Fi and F 2 .
3 - Procédé selon la revendication 1 , caractérisé en ce que les signaux reçus par le récepteur s'expriment :3 - Process according to claim 1, characterized in that the signals received by the receiver are expressed:
Z1 (0 = O1 1S1 (O + O1S2 (O + bγ (O Z2 (O = al S1 (O + O2 2S2 (O + b2 (O où si(t) est le premier flux correspondant à un premier utilisateur Ui et s2(t) le second flux correspondant à un deuxième utilisateur U2 et la perturbation apportée par le canal de propagation est composée d'un bruit additif gaussien bu(t) avec ~\ < u<2 et d'une atténuation αι υ, avec la fréquence / vérifiant 1 </< 2 et l'indice des utilisateurs u vérifiant 1 ≤ u≤2.Z 1 (0 = O 1 1 S 1 (O + O 1 S 2 (O + b γ (OZ 2 (O = al S 1 (O + O 2 2 S 2 (O + b 2 (O where si (t ) is the first flow corresponding to a first user Ui and s 2 (t) the second flow corresponding to a second user U 2 and the disturbance provided by the propagation channel is composed of a Gaussian additive noise b u (t) with ~ \ <u <2 and attenuation α ι υ , with the frequency / verifying 1 </ <2 and the index of the users u verifying 1 ≤ u≤2.
4 - Procédé selon la revendication 1 , caractérisé en ce que la communication est faite des utilisateurs vers un point d'accès.4 - Process according to claim 1, characterized in that the communication is made from users to an access point.
5 - Procédé selon la revendication 1 , caractérisé en ce que la communication est faite d'un point d'accès vers plusieurs utilisateurs. 6 - procédé selon l'une des revendications précédentes, caractérisé en ce que l'on diminue la puissance d'émission pour chaque utilisateur.5 - Process according to claim 1, characterized in that the communication is made of an access point to several users. 6 - method according to one of the preceding claims, characterized in that it decreases the transmission power for each user.
7 - Procédé selon l'une des revendications 1 à 5, caractérisé en ce que l'on utilise moins de canaux de transmission que d'utilisateurs. 7 - Method according to one of claims 1 to 5, characterized in that one uses less transmission channels than users.
EP06725501A 2005-04-01 2006-03-31 Device and method for increasing the robustness or the capacity of wireless communication systems Withdrawn EP1869798A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0503179A FR2884085B1 (en) 2005-04-01 2005-04-01 DEVICE AND METHOD FOR INCREASING THE ROBUSTNESS OR CAPACITY OF WIRELESS COMMUNICATION SYSTEMS
PCT/EP2006/061255 WO2006103295A1 (en) 2005-04-01 2006-03-31 Device and method for increasing the robustness or the capacity of wireless communication systems

Publications (1)

Publication Number Publication Date
EP1869798A1 true EP1869798A1 (en) 2007-12-26

Family

ID=35429207

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06725501A Withdrawn EP1869798A1 (en) 2005-04-01 2006-03-31 Device and method for increasing the robustness or the capacity of wireless communication systems

Country Status (5)

Country Link
US (1) US20090219898A1 (en)
EP (1) EP1869798A1 (en)
CN (1) CN101189806A (en)
FR (1) FR2884085B1 (en)
WO (1) WO2006103295A1 (en)

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5542115A (en) * 1994-06-24 1996-07-30 Pioneer Tech Development Limited Paging method and apparatus
US6122482A (en) * 1995-02-22 2000-09-19 Global Communications, Inc. Satellite broadcast receiving and distribution system
SE517380C2 (en) * 2000-10-12 2002-06-04 Ericsson Telefon Ab L M Method and apparatus for utilizing frequency space in a wireless communication system with unsymmetrical traffic congestion
KR20030056243A (en) * 2001-12-27 2003-07-04 삼성전기주식회사 Triplexer circuit and chip multilayer triplexer
TWI280687B (en) * 2002-08-09 2007-05-01 Wistron Neweb Corp Multi-patch antenna which can transmit radio signals with two frequencies
US7508798B2 (en) * 2002-12-16 2009-03-24 Nortel Networks Limited Virtual mimo communication system
JP2005341531A (en) * 2004-04-27 2005-12-08 Matsushita Electric Ind Co Ltd Wireless communications system and radio station
KR20050120441A (en) * 2004-06-18 2005-12-22 삼성전자주식회사 Transmission diversity apparatus and method using multiple antenna in a mobile communication system
US7751372B2 (en) * 2005-09-23 2010-07-06 Peter Monsen Technique for adaptive data rate communication over fading dispersive channels

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2006103295A1 *

Also Published As

Publication number Publication date
WO2006103295A1 (en) 2006-10-05
FR2884085B1 (en) 2014-08-15
US20090219898A1 (en) 2009-09-03
CN101189806A (en) 2008-05-28
FR2884085A1 (en) 2006-10-06

Similar Documents

Publication Publication Date Title
EP2499796B1 (en) Method for transmitting pre-equalized digital data, and transmitting base implementing such a method
EP2156590B1 (en) Transmission and reception of multicarrier spread-spectrum signals
EP0610988B1 (en) Multi-user spread spectrum communication system
EP1878185B1 (en) Method for the coding of an OFDM/OQAM signal using symbols with complex values, and corresponding signal, devices and computer programs
EP2253114B1 (en) Methods for transmitting and receiving a multiple carrier signal including a hold interval, and corresponding computer software products, transmission and reception devices, and signal
WO2008062131A1 (en) Transmission/reception methods and modules for a multiple-carrier multiple-antenna system with training sequence
FR2805943A1 (en) EQUALIZATION METHOD IN RECEIVERS USING A COMBINATION OF MULTI-CARRIER AND MULTIPLE ACCESS MODULATION MODULATIONS BY CODES DISTRIBUTION
EP1987645B1 (en) Transmission method with optimal power allocation emitted for multicarrier transmitter
EP1189370B1 (en) Pilot symbols transmission power
WO2015177468A1 (en) Method for transmitting a signal with a preamble and corresponding devices, signal with corresponding preamble for synchronisation of a receiver
WO2009112773A1 (en) Method for transmitting multi-carrier signals in a multi-antenna system
EP1391095B1 (en) Method for estimating the transfer function of a multicarrier signal transmission channel and corresponding receiver
FR2981232A1 (en) METHOD AND COMMUNICATION SYSTEM USING DYNAMIC MODULATION AND ENCODING SCHEMES ON BROADBAND HF COMMUNICATION CHANNELS
WO2013171417A1 (en) Method for high bit rate wireless communication using a multiple output receiver
FR2903833A1 (en) Signal receiving method for e.g. wireless telephone, involves estimating real and imaginary parts of transmission channel in neighboring region from complex values corresponding to drivers of group of region
EP3224978B1 (en) Method and device for flexible, selective ssdf relaying
EP1400051B1 (en) Reduced-sttd-interference transmission method
EP2514113B1 (en) Method for transmitting a source signal, method for receiving a transmitted signal, corresponding transmitter, receiver, signal and computer programs
EP1283605A1 (en) Method for data date increase in a communication system with N transmitters and M receivers
WO2006103295A1 (en) Device and method for increasing the robustness or the capacity of wireless communication systems
EP1244243A1 (en) Global MMSE equalisation
FR3060921B1 (en) METHOD AND SYSTEM FOR ESTIMATING A FREQUENCY EQUALIZER
FR2851383A1 (en) Wireless data transmitting process for universal mobile telecommunication system, involves estimating response of transmission channel of data transmission signal by taking into account simple carrier pilot signal
WO2007090995A2 (en) Method for receiving a signal using an improved propagation channel estimate, corresponding receiver device and computer programme product
EP2731306B1 (en) Method and system for channel de-synchronization in multicarrier communication systems

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20071029

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20151001