EP1794968A1 - Procede de realisation d'une adaptation de liaison dans un systeme de transmission mimo-ofdm-ofdm - Google Patents

Procede de realisation d'une adaptation de liaison dans un systeme de transmission mimo-ofdm-ofdm

Info

Publication number
EP1794968A1
EP1794968A1 EP05794655A EP05794655A EP1794968A1 EP 1794968 A1 EP1794968 A1 EP 1794968A1 EP 05794655 A EP05794655 A EP 05794655A EP 05794655 A EP05794655 A EP 05794655A EP 1794968 A1 EP1794968 A1 EP 1794968A1
Authority
EP
European Patent Office
Prior art keywords
channel estimation
data
sequence
transmission
ofdm
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Withdrawn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
EP05794655A
Other languages
German (de)
English (en)
Inventor
Karsten BRÜNINGHAUS
Uwe Schwark
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Publication of EP1794968A1 publication Critical patent/EP1794968A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/1607—Details of the supervisory signal
    • H04L1/1671—Details of the supervisory signal the supervisory signal being transmitted together with control information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0226—Channel estimation using sounding signals sounding signals per se
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals
    • H04L27/2613—Structure of the reference signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals
    • H04L27/2613—Structure of the reference signals
    • H04L27/26136—Pilot sequence conveying additional information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/1607—Details of the supervisory signal
    • H04L1/1685—Details of the supervisory signal the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0044—Arrangements for allocating sub-channels of the transmission path allocation of payload

Definitions

  • the present invention relates to a method for implementing a link adaptation in a MIMO-OFDM (Multiple Input Multiple Output) transmission system, and in particular to a multi-antenna system which will be used in future high-speed WLANs (Wireless Local Area Network), but also in mobile radio systems with multi-antenna technology can be used.
  • MIMO-OFDM Multiple Input Multiple Output
  • WLANs Wireless Local Area Network
  • MIMO-OFDM transmission systems MIMO, Multiple Input Multiple Output
  • ⁇ che depending on the channel characteristics increase the spectral efficiency by spatially "multiplexing.”
  • the full power of such a multi-antenna systems can only then achieved if the transmitter to be used admirska ⁇ nal a-priori, that is, in advance, is known.
  • the invention has the object of providing a method for implementing a link adaptation in a MIMO-OFDM transmission system, ie, to allow busbar system in a Mehranten ⁇ , whereby in addition to a maximum Effi ⁇ efficiency and a physical backward compatibility to be ⁇ already existing stations or transmission systems is possible.
  • the postamble structure for each antenna having a channel estimation section with a channel estimation sequence and a transmission mode in a respective station based on the received channel estimation sequence is selected, a short-term channel knowledge can be determined with reduced overhead and thus a connection adaptation to the prevailing ambient conditions be made possible.
  • the Postambel Modell estimation sequence based on the received channel ⁇ the Postambel Modell estimation sequence a further postamble ⁇ structure established and another data block immediately attached the time, wherein the further Postambelfigured for each antenna a signaling section of a signaling sequence for signaling the selected Koch ⁇ transfer mode and a further channel estimation section with ei ⁇ ner further channel estimation sequence, based on the basic If the received further channel estimation sequence and / or the signaled transmission mode, a further adapted transmission mode is selected.
  • the short-term channel knowledge can thereby be further improved, as a result of which an achievable data rate of the useful data bits to be transmitted error-free continues to increase.
  • the further transmission mode is equal to the signaled transmission mode. Due to this binding assignment, a signaling overhead is minimal.
  • the further transmission mode can be further changed in relation to the signalized transmission mode, as a result of which, for example, in the knowledge of local ambient conditions, a connection adaptation can be further optimized.
  • a changed transmission mode can be completely signaled back, preferably only the transmission mode change is back-signaled, whereby an efficiency in transmission can be further improved.
  • the length of the signaling ⁇ tion section and the length of the channel estimation section can be explicitly transmitted and thereby increases the reliability of detection.
  • the channel estimation sequence of the postamble structure is transmitted successively on each antenna.
  • the channel estimation sequence of the further postamble structure for the respective antennas preferably consists of an alignment of the OFDM symbols
  • c m (n) g m ⁇ (n) c ml (n) --- c ml (n) g m2 (n) c m2 (n) --- c m2 (n) - • g mD (n) c mD (ny ⁇ c mD (n)
  • C (k) is a base channel estimation signal in the frequency domain
  • M R and M ⁇ are a number of receive and transmit antennas
  • d 1, ..., D an index of the spatial data stream
  • D the maximum number of spatial data streams over all subcarriers
  • D maxD
  • n 1,..., N a sampling index
  • N the number of samples per OFDM symbol
  • g m , d (n) a guard interval sequence of a guard interval
  • k a subcarrier index
  • j the number of repetitions of the OFDM symbols c m / d (n) and u kmi a conjugate complex m-tes
  • Row and d-th column element of the left input matrix U ⁇ represents.
  • the method is preferably carried out in an OFDM transmission system in accordance with the IEEE 802.11 standard and in particular within a local RTS / CTS signaling or a data polling mechanism or data polling. In this way, an efficiency of already existing conventional WLAN communication systems can be subsequently improved.
  • FIG. 1 shows a simplified data frame structure for the RTS / CTS data exchange according to the standard IEEE 802.11;
  • FIG. 2 shows a simplified data frame structure for the RTS / CTS data exchange modified according to the invention in accordance with a first exemplary embodiment
  • FIG. 3 shows a simplified data frame structure for illustrating a channel estimation section
  • FIG. 4 shows a simplified data frame structure for illustrating a postamble structure according to the invention with channel estimation sections in a multi-antenna system
  • FIG. 5 shows a simplified data frame structure for illustrating another postamble structure according to the invention with a further channel estimation section and a signaling section in a multi-antenna system
  • FIG. 6 shows a simplified data frame structure for an RTS / CTS data exchange according to a second exemplary embodiment
  • FIG 8 is a simplified data frame structure for a DA-th polling mechanism according to a fourth exporting ⁇ approximately example.
  • the invention will be described below with reference to a WLAN (Wireless Local Area Network) transmission system according to IEEE 802.11 standard as OFDM transmission system, but in principle also alternative OFDM transmission systems are conceivable.
  • OFDM symbols are used in an OFDM (Orthogonal Frequency Division Multiplexing) transmission system. Lexclar Such Multiplexing is particularly suitable for highly disturbed terrestrial transmissions innovative digital broadcast signals, as it is sensitive to echo un ⁇ .
  • a transmission ready signal RTS Ready To Send
  • DIFS DIFS Interfram Space
  • RTS Read To Send
  • the ready-to- transmit signal RTS there is a so-called "duration" block, which makes possible a reservation of a current transmission right with a predetermined time duration
  • SIFS Short Interframe Space
  • a ready signal CTS Certo Send
  • the broadcast ⁇ station S is a payload packet data from the transmitting station S to the receiving station E.
  • the first and second waiting times SIFS and DIFS are 16 microseconds and 34 microseconds.
  • the Zeitwer ⁇ te contained in particular in the "duration" blocks the transmission and reception ready signals RTS and CTS put this in the other is decentralized within reach of Sen ⁇ or receiving station S and E located stations A of the communication network a so-called network access ⁇ vector NAV (Network allocation Vector), that indicates how long a transmission on the radio medium, or the icosme ⁇ dium from the respective station can not be performed.
  • NAV Network allocation Vector
  • a transmission channel to be used is known "a-priori" in the transmitting station S, ie in advance
  • Such information is usually also referred to as short-term channel knowledge.
  • transmitting station and receiving station used it should be noted that these stations are essentially based on transmitting and receiving. catching of payload data and not on the transmission or reception of, for example, the signaling blocks RTS, CTS and ACK. As can be seen from FIG. 1, the transmitting station S therefore transmits the useful data Data, but it also receives the signaling data CTS and ACK from the receiving station E.
  • DFT discrete Fourier transformation
  • OFDM Orthogonal Frequency Division Multiplexing
  • N number of samples per OFDM symbol (depending on the D / A or A / D converter rate)
  • ⁇ Tk Vector with data symbols transmitted on the kth subcarrier.
  • x Tk transmit signal vector (in the frequency domain) on the kth subcarrier
  • Y R * 'Yr * Reception signal vector (in the frequency domain without Rau ⁇ rule) on the k-th subcarrier
  • k H channel matrix of the kth subcarrier
  • H / c . m . m, 'm • r "th row and m t -th column element of the channel matrix H k ⁇ corresponds to the complex transmission factor ⁇ between the m r th receiving and m t th transmitting antenna u kd:..
  • Rows, B number of columns
  • Figure 2 shows a simplified data frame structure for the RTS / CTS exchange of a decentrally organized carrier multiple access system (DCF) according to a preferred first embodiment, wherein like reference characters designate like or corresponding data blocks or elements as characterized in Figure 1 be ⁇ and subsequently a repeated description is waived.
  • DCF decentrally organized carrier multiple access system
  • Postamble structure Pl are attached directly in time, which for each antenna a channel estimation section with a Ka ⁇
  • a further postamble structure P2 can be defined and a further data block, which for example has only unsatisfactory or insufficient information for MIMO channel identification, is appended in time immediately, said further Postambel Smart P2 antenna for each An ⁇ a signaling section of a signaling sequence for signaling the selected admirsmo ⁇ dus and a further channel estimation section with a further channel estimation sequence, wherein on the basis of the received additional channel estimation sequence and / or signaled ⁇ overbased transmission mode, a further transmission mode in the transmitting station S is selected, then the useful ⁇ data dATA having a maximum achievable data rate is transmitted without errors bits to be transmitted.
  • a Postam ⁇ bel Design Pl for MIMO channel identification in the Sendesta- tion appended S After expiration of the second waiting time SIFS, a ready-to-receive signal CTS is sent by the receiving station E and immediately after it another postamble structure P2 is added, which contains both the "most effective" transmission mode (coding, number of parallel data streams per subcarrier and their modulation, art of the MIMO Preproces- sings for example SVD or V-Blast) from the perspective of delivery of messages ⁇ on e in a signaling section signaled as well as suitable further pilot symbols or another suitable channel estimation sequence for determining preprocessing matrices in the transmitting station S sent Let. assuming that the transmission channel is reciprocal, ie its channel Shanks are dependent on each other in terms of its transmission direction.
  • the transmitting station S is obliged to use the transmission mode predetermined or signaled by the receiving station E as part of the acknowledgment signal CTS. That is, the further transmission mode used in the transmitting station S is equal to the transmission mode signaled by the further postamble structure P2.
  • a further return signaling within, for example, the user data packet Data can be dispensed with, whereby a signaling overhead can be limited.
  • the transmitting station S can further change the transmission mode selected by the receiving station E, as specified in the signaling field of the further postamble structure P2.
  • a back-signaled ⁇ tion is the in the transmitting station S currently newly hired another transfer mode required.
  • the temporal direct appending the postambles Pl and P2 to the send signal RTS as well as to the Empfangsbe ⁇ readiness signal CTS is for conventional 802.11a and 802.11g devices with only a single antenna opted- partly transparent, resulting in an advantageous physi ⁇ cal backward compatibility existing at already Stations or systems results. Accordingly, with the invention Not only do these processes increase efficiency, but they also provide backward compatibility with conventional systems.
  • the transmitting station S can make no prediction about the duration of the useful data packet Data in the RTS signaling due to lack of information about the transmission mode to be used, during the initialization of the so-called "durati- on” block within the ready to send signal RTS, from the later, the network access vector NAV is derived to make an "optimistic estimate" which is certainly smaller or equal to an actual time duration of a user data packet Data to be sent. This is possible, for example, by assuming the maximum physical data rate.
  • Such a procedure is uncritical insofar as interference is avoided by the used carrier multiple access method with collision avoidance (CSMA / CA, Carrier Cense Multiple Access with Collision Avoidance). Since the other stations A only wake up earlier than necessary according to FIG. 2, not all energy-saving options are used in this procedure.
  • CSMA / CA Carrier Cense Multiple Access with Collision Avoidance
  • the network access vector NAV can then be set "exactly" or correctly in the receiving station E if the transmitting station S is forced to actually use the transmission modes selected and defined by the receiving station E.
  • the receiving station E must also be aware of how many data bits the transmitting station wants to transmit S. This information can either be transmitted as part of the postamble structure P1 or implicitly also be derived from the "duration" block. As a result, if the hypothetical data rate assumed in the transmitting station S of the receiving station E is known, the method can be made more effective.
  • RTS / CTS signaling for link adaptation or link adaptation illustrated in FIG. 2 should ideally be used adaptively. This means that in each case when a data connection between two stations is relatively long (for example based on the coherence time of the channel) and consequently channel information is outdated, a renewed RTS / CTS signaling in the form described is to be refreshed the channel information is set ein ⁇ . Otherwise dispensed a corresponding Signa ⁇ capitalization, if it is not already provided to avoid the "hidden nodes" so-called. Had connection In this Zu ⁇ also pointed out the operational settings in accordance with IEEE 802.11.
  • RTS / CTS data exchange for connection adaptation or "link adaptation" should also be the length of the payload data packet Data to be transmitted.
  • the additional signaling overhead is counterproductive for short payload data packets and should therefore be avoided even if the actual data transmission can be made more efficient.
  • FIG. 3 shows a channel estimating section KAl with a channel estimation sequence ⁇ c (n) as it is preferably used in a postamble Pl.
  • the arrangement of these channel estimation sections KAl based on the plurality of antennas 1 to M ⁇ is shown in Fi gur 4, wherein the channel estimation section is transmitting at its channel estimation sequence successively on each antenna 1 to M ⁇ ge ⁇ .
  • C (k) is a base channel estimation signal in the frequency domain
  • m 1, ...
  • M T is an antenna index
  • M ⁇ is a number of transmit
  • x is an arbitrary run index
  • d 1
  • D is an index spatial data stream
  • D is the maximum number of spatial data streams over all subcarriers
  • D maxZ ⁇
  • n 1, ..., N NEN egg sample index
  • N is the number of samples per OFDM Sym bol ⁇ , g m, x (n) a guard interval sequence of a guard interval (G, GG)
  • k represents a subcarrier index
  • j represents the number of repetitions of the OFDM symbols c m / d (n).
  • the basic channel estimation signal is the value
  • c (k) _ 2626 (Uii, ui, i-1,1,1,1,1,1,1-ii, i, ii, i-1,1,1,1,1,0,
  • the postamble structure P1 makes it possible for the receiving station E to determine all complex transmission factors H k , m r , m t .
  • FIG 4 a not particularly bandwidth-efficient but very simple for the receiving station E from complexity overview variant in which vorste ⁇ channel estimation sections KAI basis described with their jewei ⁇ time channel estimation episodes successively, ie one after the other, on each transmit antenna 1 to M ⁇ to send.
  • the Be ⁇ drawing shown in Figure 4 for the transmit antennas 1 to M ⁇ in the same way also applies to receive antennas 1 to M R , if a corre sponding station receives the postamble structure Pl. That is, the parameter ⁇ M denotes both destation the number of transmit and the number of receive antennas in a respective Sen ⁇ and M R corresponding to the number of transmit and Emp ⁇ fang antennas at the receiving station E.
  • the length of the postamble Pl is not required. Because of the special Postambel Modell it is relatively easy, the length implicitly example ⁇ way of determining the autocorrelation function (ACF) at intervals of 64 samples over a time window to determine at least the same magnitude.
  • the number of transmit antennas can also be made known in advance via an expansion of a so-called "capability information field" or other "information elements" to be defined, such as are provided, for example, within IEEE 802.11. Since the postamble Pl not necessarily be attached to any RTS / CTS signaling needs is thus only to detect whether a postamble over ⁇ ever existent.
  • the receiving station E on the basis of the channel matrices H k carries out a selection of the spatial eigenmodes to be used by the transmitting station S for each subcarrier k, which then becomes the actual chen data transmission to be used.
  • the basic requirement for the applicability of this scheme is that the transmission channel is reciprocal and sufficiently time-invariant. Sufficient time invariance is present when the transmission characteristics of the channel do not change significantly from the measurement of the transmission channel via the evaluation of the channel estimation until the end of the user data transmission.
  • the spatial eigenmodes can be defined in the receiving station E by a singular value decomposition (SVD, Singular Value Decomposition) of the channel matrices
  • SVD singular value decomposition
  • U and V are unitary matrices, while S having a diagonal structure whose entries ⁇ the damping values of the respective eigenmodes represent.
  • Channel matrix represents.
  • c m (n) g m ⁇ (n) c m ⁇ («) ⁇ • ⁇ c m ⁇ (n) g ma (n) c ma (n) ••• c M-2 (n) -g mJ) (n ) c mM (n) ••• c mJ) (n) and
  • NEN signaling section SI for signaling the locally already determined transmission mode has.
  • D max ⁇ D k ⁇ must be observed.
  • the preprocessing vectors v k , d to be used can be derived directly from the post-preamble parts or the channel estimation sequence c m , d (n ), because it applies
  • variable S k , d in this case represents the damping factor, which is linked to the eigenmode u k , d and an element of
  • Diagonal matrix S k represents.
  • the scope of the feedback signaling or re-signaling is reduced, since instead of M R sequence pairs for the channel identification in the transmitting station only D sequence pairs are required.
  • D ⁇ min ⁇ M ⁇ , M R ⁇ where practically D ⁇ min ⁇ M ⁇ , M R ⁇ is selected.
  • the signaling information of the signaling section SI shown in Figure 5 is genmodi and to transmit the physical transmission parameters for the respective Ei ⁇ thus required for the respectively selected transmission ⁇ mode. It can be transmitted either before or after the channel estimation component or the further channel estimation section KA2, the latter being illustrated in FIG. Will however maintain the channel estimation section KA2 over ⁇ , so it makes sense to use the same physical Sprint ⁇ transfer mode as the receiving station E and the CTS. This variant also makes it possible to transfer the length of the signaled ltechniksabterrorisms SI as well as the length of the additional channel ⁇ estimated portion KA2 explicit what a Detek- increased tion safety.
  • the signaling section SI is transmitted according to FIG. 5 after the further channel estimation section KA2, then at least the length of the sequence for channel estimation is to be derived implicitly from the received signal.
  • the signaling information is advantageous in this case that the identified eigenmodes supply already for Studentstra ⁇ can be used, whereby upon application of spatial multiplexing either
  • Transmission time can be saved or the transmission reliability can be increased when using the diversity method.
  • Figure 6 shows a simplified data frame structure for a RTS / CTS exchange of data for illustrating a method for implementing a link adaptation according to a sau ⁇ th embodiment, wherein like reference characters designate the same or corresponding elements or data blocks as reindeer in the Figu ⁇ 1 to 5 designate and a repeated description is omitted below.
  • like reference characters designate the same or corresponding elements or data blocks as reindeer in the Figu ⁇ 1 to 5 designate and a repeated description is omitted below.
  • the postamble structure P1 can be used, as a result of which the signaling overhead is considerably reduced.
  • the transmitting station S decides autonomously which transmission mode is to be used for the payload data Data.
  • the interference situation at the receiving station E is not reciprocal and is not detected or evaluated at the transmitting station S. Assuming, however, that interferences due to the CSMA / CA method used in 802.11 are avoided anyway, this aspect does not play a role.
  • Transmit antennas then is a channel estimate sequence pair c (n) within the postamble structure Pl redundant and can therefore be omitted, which further reduces the overhead.
  • the present method of establishing a connection adaptation can not only be used in connection with the RTS / CTS signaling of the 802.11 standard, but can also be used, as in FIGS. 7 and 8, in connection with the polling mechanisms defined in the same standard or data retrieval mechanisms are carried out.
  • Figure 7 shows a simplified data frame structure for a data retrieval mechanism for illustrating a method according to a third embodiment, wherein the same loading ⁇ reference numbers again designate like or corresponding elements sawn drawing as in Figures 1 to 6 and a repeated Be ⁇ scription thereof will be omitted below.
  • a data block CF-POL for initializing a data retrieval mechanism or a polling mechanism can likewise be attached to a postamble structure Pl, wherein in turn a transmitting station S transmits the payload data Data after a waiting time SIFS and selection of a transmission mode.
  • a transmitting station S transmits the payload data Data after a waiting time SIFS and selection of a transmission mode.
  • a transmitting station S transmits the payload data Data after a waiting time SIFS and selection of a transmission mode.
  • FIG. 8 shows a simplified data frame structure for the data fetching mechanism for illustrating a method for implementing a connection adaptation according to a fourth exemplary embodiment, where identical reference numerals denote identical or corresponding elements or data blocks. NEN as in Figures 1 to 7 and a repeated Be ⁇ description will be omitted below.
  • the invention has been described above with reference to an OFDM transmission system according to the IEEE 802.11 standard. However, it is not limited thereto and equally includes alternative MIMO-OFDM transmission systems.

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

Abstract

La présente invention concerne un procédé permettant de réaliser une adaptation de liaison dans un système de transmission MIMO-OFDM. On attache une structure postambule (P1) chronologiquement immédiatement à un bloc de données (CTS) qui n'a pas d'information suffisante pour l'identification de canal. Cette structure postambule (P1) présente, pour chaque antenne, une section d'évaluation de canal ayant une séquence d'évaluation de canal. Sur la base de la séquence d'évaluation de canal reçue, on sélectionne un mode de transmission dans une station respective.
EP05794655A 2004-09-30 2005-09-30 Procede de realisation d'une adaptation de liaison dans un systeme de transmission mimo-ofdm-ofdm Withdrawn EP1794968A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102004047746A DE102004047746A1 (de) 2004-09-30 2004-09-30 Verfahren zur Realisierung einer Verbindungsanpassung in einem MIMO-OFDM-Übertragungssystem
PCT/EP2005/054933 WO2006035070A1 (fr) 2004-09-30 2005-09-30 Procede de realisation d'une adaptation de liaison dans un systeme de transmission mimo-ofdm-ofdm

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EP1794968A1 true EP1794968A1 (fr) 2007-06-13

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EP (1) EP1794968A1 (fr)
DE (1) DE102004047746A1 (fr)
WO (1) WO2006035070A1 (fr)

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