Method and system for multiple cooperative OMAMRC with FDM transmissions and per subband

Abstract

The invention relates to a method for transmitting messages intended for an OMAMRC telecommunication system having N nodes and a destination, the nodes comprising M sources (sii [epsilon] {1,..., M}), optionally L relays (r1,..., rL). The transport is FDM transport performed on a belt divided into B sub-belts that are orthogonal to each other. The method comprises:-transmitting M first redundancies of M messages of the M sources during a first phase; -receiving, via the nodes, scheduling information (Formula I) indicating a selected source of each subband that has not been correctly decoded by the destination and referred to as the source to assist, the scheduling information taking into account the constraints of the maximum transmit power of each node; and-an active node transmitting correct knowledge of a single selected source (si) of a single second redundancy of a single message with a single source on a single sub-band during a single retransmission interval of the second phase, the transmission of one node on multiple sub-bands being constrained by the maximum transmit power of the node.

Description

Technical Field

[0001] The present invention relates to the field of digital communications. In this field, the invention more particularly relates to the transmission of coded data between at least two sources and a destination with relaying by the cooperation of at least one node, which may be one of the sources or a relay separate from the source.

[0002] It should be understood that a repeater has no messages to transmit. A repeater is a node dedicated to relaying messages from a source, while the source has its own messages to transmit, and in some cases the source may also relay messages from other sources, i.e. in this case the source is said to be cooperative.

[0003] There are many relay technologies, namely: "amplify and forward", "decode and forward", "compress and forward", "non-orthogonal amplify and forward", "dynamic decode and forward", etc.

[0004] The invention is particularly, but not exclusively, applicable to the transmission of data via a mobile network (eg for real-time applications) or the transmission of data via, for example, a sensor network.

[0005] Such a sensor network is a multi-user network consisting of several sources, several repeaters and receivers using an orthogonal multiple access scheme of transmission channels between repeaters and destinations, denoted OMAMRC (Orthogonal Multiple Access Multiple Relay Channel). Background Art

[0006] From application WO 2021 / 260308 published on December 30, 2021, an OMAMRC transmission system implementing frequency division multiplexing (FDM) type transmission is known.

[0007] like Figure 1 As shown, the described OMAMRC telecommunication system includes source sets belonging to M sources, optionally belonging to a set of repeaters The set of L relays (M≥2, L≥0), and the destination d. Each source in communicates with a single destination with the assistance of other sources that collaborate (user collaboration) and relays. Nodes include relays and sources that can act as relays when not transmitting their own messages.

[0008] The nodes, ie the M sources and the L repeaters, access the transmission channel according to an orthogonal frequency multiple access scheme and operate according to a full-duplex mode which allows them to listen to the transmissions of other nodes without any interference.

[0009] The band of the channel is divided into B subbands, assuming that the number of subbands is greater than or equal to the number of sources: B ≥ M. Each subband associated with a time slot determines F channel usage (F resource elements). For each time slot, FDM transmission occurs on a band divided into B mutually orthogonal subbands.

[0010] like Figure 2 As shown, the frame transmission period lasts 1+T used time slots, where T used ≤T max , and T max is the maximum number of time slots in a transmission period. For each time slot, no subband, one or more subbands are assigned to a node, depending on the partition, and for each time slot, each subband is assigned to at most one node.

[0011] During the first time slot (first phase), assuming B ≥ M, all sources x 1 ,…,x M The transmission is performed on one or more sub-bands assigned to each source, respectively.

[0012] During the following time slots, called retransmission time slots (second phase), only nodes selected from the source and the repeater transmit, and their transmissions occur on one or more subbands assigned to them respectively according to the partition determined for each current time slot. Therefore, for each of these time slots, the destination determines the B-dimensional vector of nodes to transmit for time slot t under the constraint that each subband is assigned to at most one node

[0013] The selected node for cooperative transmission transmits after multi-user encoding the word it has correctly decoded The selected node can use network coding and joint network channel coding to transmit parity determined from messages of its correctly decoded source set. Other nodes and destinations can improve their own decoding by utilizing the selected node's transmissions and can therefore update their correctly decoded source sets.

[0014] Therefore, the destination uses the feedback channel to control the transmission of the nodes. This allows to improve the spectrum efficiency and reliability by increasing the probability that the destination can decode all sources. Summary of the invention

[0015] The object of the invention is a method for transmitting framed messages intended for use in a telecommunication system comprising a destination and N nodes, these nodes comprising M sources and NM repeaters, N≥M≥2, wherein orthogonal multiple access is provided to the transmission channel between the N nodes, the maximum number of time slots per transmission frame being T+T distributed between a first phase of T time slots and a second phase of at least one time slot, called a retransmission slotmax , 1≤T max , wherein the source message has been coded before transmission according to an incremental redundancy type coding generating a number of redundancies, the transmission being a frequency division multiplexing type transmission carried out on a band divided into B≥2 mutually orthogonal sub-bands, M≤BT. The method comprises:

[0016] - transmitting during the first phase M first redundancies of the M messages of the M sources;

[0017] - receiving, via the nodes, scheduling information indicating the selected sources for each subband that have not been correctly decoded by the destination, called sources to be assisted, the scheduling information taking into account the constraints of the maximum transmission power of each node;

[0018] - A node that transmits with correct knowledge of the same selected source on the same subband for the same retransmission slot of this phase 2, with the same second redundancy of the same message of this same source, is called an active node, wherein the transmission of a node on several subbands is constrained by the maximum transmission power of the node.

[0019] Since all sources transmit their first redundancy on one or more subbands of one of the T time slots of the phase 1, the allocation of orthogonal subbands between the sources allows reducing the time required to transmit data. When the phase 1 comprises a single time slot, i.e. T=1, then all sources transmit simultaneously during the same time slot, which allows providing a very fast phase 1. Therefore, such an approach is very suitable for delay-critical services.

[0020] The simultaneous transmission of the same redundancy via all nodes with correct knowledge of the same source during the same retransmission slot of this phase 2 allows to increase power when receiving at the destination, and therefore allows to significantly reduce the probability of false alarms (i.e. incorrect decoding). This improvement optimizes the throughput and / or allows to reduce the transmission power of the source for the same throughput. The nodes with correct knowledge of the same source are also the nodes that have correctly decoded the same source as well as the source itself. These nodes other than the source can collaborate by transmitting the same redundancy of the same source during the retransmission slot. The transmission of these nodes is said to be collaborative.

[0021] Where the system includes repeaters in addition to the source, a cooperative transmission is a transmission through a repeater or a transmission by a source that is able to assist the destination in decoding a source that it has not yet correctly decoded.

[0022] A cooperative transmission is a transmission via a node that contains information related to at least one message from another node. A repeater's transmission is essentially a cooperative transmission, but is also a transmission by a (cooperation-capable) source that includes in its transmission information related to at least one message from another source. The cooperation of nodes ensures an increase in transmission reliability.

[0023] The transmission of a node on a subband depends on its transmissions on other subbands. In fact, a node has a transmission power P that must be distributed over all subbands on which it is active. The power transmitted by a node for a subband is a function of the power it transmits on other subbands on which it is active, and the sum of the powers transmitted per subband cannot exceed P.

[0024] The selection of the source to assist is implemented by a device called a scheduler, which may equally correspond to the destination, such as another device having knowledge about the link qualities within the system under consideration.

[0025] The scheduler feeds scheduling information back to the node identifying the selected source to assist (i.e., the source selected from the sources that have not been correctly decoded by the destination). The scheduling information further includes allocating subbands to enable the node to retransmit the redundancy of the selected source. For example, this information can be in the form of an integer Q: For B subbands, the integer Q can be determined as follows, Q = p 0 +p 1 M+…+p B-1 M B-1 , where p i +1 is the same as the i-th th +1 identifier of the source (assumed to be in the set {1,..,M}) to which the band (assumed to be its value in the set {1,…,B}) is associated.

[0026] Another object of the invention is a method for transmitting framed messages implemented by a telecommunication device, intended for use in a telecommunication system, the telecommunication system having N nodes and the device, the nodes comprising M sources and NM repeaters, N≥M≥2, wherein orthogonal multiple access is provided to the transmission channel between the N nodes, the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot, called a retransmission time slot, being T+T max , 1≤T max , wherein the source message has been coded before transmission according to an incremental redundancy type coding generating a number of redundancies, the transmission being a frequency division multiplexing type transmission carried out on a band divided into B mutually orthogonal sub-bands, M≤BT. The method comprises:

[0027] - receiving, by the device during the first phase, M first redundancies of the M messages of the M sources simultaneously on at least M subbands;

[0028] - the device transmits scheduling information indicating selected sources per subband that have not been correctly decoded by the device, referred to as sources to be assisted, wherein the scheduling information takes into account a constraint on the maximum transmission power of each node;

[0029] - The device receives, for the same retransmission slot of the phase 2, the same second redundancy of the same selected source on the same subband and originating from a different node having correct knowledge of the same source.

[0030] Another object of the invention is a method for transmitting framed messages implemented by a telecommunication device, intended for use in a telecommunication system, the telecommunication system having N nodes and a destination, the nodes comprising M sources and NM repeaters, N≥M≥2, the device being one of the sources, wherein orthogonal multiple access is provided to a transmission channel between the N nodes and the destination, wherein the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot, called a retransmission time slot, is T+T max , 1≤T max , wherein the transmission is of frequency division multiplexing type on a band divided into B mutually orthogonal sub-bands, M≤BT. The method comprises:

[0031] - encoding the message before transmission according to an incremental redundancy type encoding generating several redundancies;

[0032] - a first redundancy of messages transmitted from the source during the first phase;

[0033] - receiving scheduling information indicating selected sources for each subband that have not been correctly decoded by the destination, referred to as sources to be assisted, wherein the scheduling information takes into account a constraint on the maximum transmission power of each node;

[0034] - During the retransmission slots of this second phase, for sources for which the device has correct knowledge, a second redundancy of the message of the selected source is transmitted on the corresponding subbands, wherein the transmission of the device on several subbands is constrained by a maximum transmission power.

[0035] Another object of the invention is a telecommunication device for transmitting framed messages intended for use in a telecommunication system comprising N nodes comprising M sources and NM repeaters, N≥M≥2, and a destination d, wherein orthogonal multiple access is provided to the transmission channel between the N nodes and the destination, wherein the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot, called a retransmission time slot, is T+T max , 1≤T max, the transmission is of frequency division multiplexing type carried out on a band divided into B≥2 mutually orthogonal sub-bands, M≤BT, the device corresponding to one of these sources comprises at least one microprocessor, a memory, a transmission chain and a reception chain, the transmission chain comprising an encoder implementing an incremental redundancy type coding generating multiple redundancies of the same message to be transmitted and causing:

[0036] - the transmission chain is capable of transmitting a first redundancy of the message to be transmitted during the first phase;

[0037] -The receive chain is capable of receiving scheduling information of size B The scheduling information indicates the selected sources for each subband that have not been correctly decoded by the destination, referred to as sources to be assisted, and the scheduling information takes into account the constraint of the maximum transmission power of each node;

[0038] - The transmission chain is also capable of transmitting, during the retransmission slots of this phase 2, a second redundancy of the message of the selected source on the corresponding subbands for the sources for which the device has correct knowledge, wherein the transmission on several subbands is subject to a maximum transmission power constraint.

[0039] Another object of the invention is a telecommunication device for transmitting framed messages intended for use in a telecommunication system comprising N nodes comprising M sources and NM repeaters, N≥M≥2, and a destination d, wherein orthogonal multiple access is provided to the transmission channel between the N nodes and the destination, wherein the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot called a retransmission time slot is T+T max , 1≤T max , wherein the transmission is of frequency division multiplexing type on a band divided into B≥2 mutually orthogonal sub-bands, M≤BT. The device corresponding to one of these sources comprises at least one microprocessor, a memory, a transmission chain and a reception chain, and is such that:

[0040] - the receiving chain is capable of simultaneously receiving, during the first phase, on at least M subbands, M first redundancies of the M messages of the M sources;

[0041] - the transmission chain is capable of transmitting scheduling information indicating the selected sources for each subband that have not yet been correctly decoded by the device, called sources to be assisted, the scheduling information taking into account the constraints of the maximum transmission power of each node;

[0042] - The receiving chain is also able to receive, for the same retransmission slot of the phase 2, the same second redundancy of the same selected source on the same subband and originating from a different node having correct knowledge of the same source.

[0043] Another object of the present invention is a telecommunication system comprising a destination and N nodes, the nodes comprising M sources and NM repeaters, M≥2, wherein orthogonal multiple access is used for a transmission channel between the N nodes and the destination, the telecommunication system being capable of implementing the transmission method according to one of the objects of the present invention.

[0044] According to one embodiment, the scheduling information is based on the mutual information for each subband b of the equivalent channel between the nodes having correct knowledge of the same source to be assisted and the destination To be determined.

[0045] The criteria considered by means of mutual information make it possible to tend to maximize the spectral efficiency. The mutual information depends on the number of subbands for which a node is active, i.e. the redundancy of its transmission of the same source or of several sources of these different subbands. The selection of the source to be assisted therefore takes into account the fact that each node that transmits a redundancy of the selected source to be assisted transmits on the allocated subbands and this is the case for the various sources to be assisted of which it has correct knowledge. The determination of this scheduling information is therefore subject to the constraint of the maximum transmission power of each node.

[0046] According to one embodiment, the transmission method further comprises:

[0047] - At the end of this phase 1 transmission slot, the source set is transmitted which is correctly decoded by these nodes.

[0048] The information transmitted by these nodes allows the destination to select sources to assist it in decoding the greatest number of sources.

[0049] According to one embodiment, the transmission method further comprises:

[0050] - receiving, via the nodes, the set of sources correctly decoded by the destination from among the sources received by the destination during the first phase;

[0051] - At the end of this 1st phase, the source set that was correctly decoded by these nodes and not yet correctly decoded by the destination is transmitted via these nodes.

[0052] According to the protocol, after receiving the data transmitted during the 1st transmission time slot, the destination feeds back its correctly decoded set of sources to the node. This feedback can occur via a control channel. According to a particularly simple embodiment, the destination feeds back M bits indicating whether each of the M sources is correctly decoded. If all sources are correctly decoded by the destination, that is, its correctly decoded set of sources contains M sources, a new frame is transmitted. The information transmitted by the node allows the destination to more efficiently select sources to assist it in decoding the maximum number of sources.

[0053] According to one embodiment, the scheduling information is obtained by comparing the sum of the mutual information on each subband b of the equivalent channels between those nodes having correct knowledge of the same source to be assisted and the destination between the different possible scheduling information of the source to be assisted in each subband.

[0054] According to one embodiment, in the case where the scheduling information comprises B components, these components are determined sequentially one subband after another and, for a given subband b, the component is obtained by determining the maximum value of a sum between the sources to be assisted, the sum comprising, on the one hand, the sum of the mutual information of equivalent channels between these nodes having correct knowledge of the same source to be assisted and the destination over subbands 1 to b-1 and, on the other hand, the mutual information of equivalent channels between these nodes having correct knowledge of the same source to be assisted and the destination for this subband b.

[0055] According to one embodiment, the transmission channel of the subband b between the node a taken from the N nodes and the destination is represented as Among them, h a,b is the amplitude and is the phase factor, which enables each of these nodes with correct knowledge of the same selected source to know the phase of the transmission channel between the node a and the destination When , each of these nodes transmits the same second redundant transmission to the same source modulated by the phase factor, Among them, j 2 = -1, and among them, corresponds to the amplitude h of the transmission channel between the node and the destination a,b The conjugate amount Divide by its norm |h a,b |.

[0056] According to one embodiment, the transmission channel of the subband b between the node a taken from the N nodes and the destination is represented as Among them, h a,d is the amplitude and is a phase factor, wherein the nodes of the subband b having correct knowledge of the same selected source are grouped into a first group of nodes and a second group of nodes, such that each node in the first group knows the phase of the transmission channel between the node and the destination for the subband b And each node in the second group does not know the phase of the transmission channel between the node and the destination of the subband b The method causes the transmission of the same second redundancy to the source via the node a in the first group to be modulated by the phase factor, Among them, j 2= -1, and among them, corresponds to the amplitude h of the transmission channel between the node a and the destination a,b The conjugate amount Divide by its norm |h a,b |, and causes transmission of the same second redundancy to the source via node a in the second group to occur without phase correction.

[0057] According to one embodiment, for the same source, the first redundancy and the second redundancy are different.

[0058] These different embodiments can be combined with each other to form further embodiments.

[0059] The device and system according to the invention are capable of implementing various embodiments of the method according to the invention.

[0060] Another object of the invention is each specific software application on one or more information media, wherein said applications comprise program instructions capable of implementing the transmission method when these applications are executed by a processor.

[0061] Another object of the invention is configured memories comprising instruction codes corresponding respectively to specific applications.

[0062] The memory may be incorporated in any entity or device capable of storing a program. The memory may be of the ROM type (for example a CD ROM or a microelectronic circuit ROM), or even of the magnetic type (for example a USB key or a hard disk).

[0063] Furthermore, each specific application according to the present invention may be downloaded from a server accessible over an Internet type network.

[0064] The optional features explained above within the scope of the transmission method may optionally be applied to the aforementioned software application and memory. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Other characteristics and advantages of the invention will become more clearly apparent after reading the following description of an embodiment provided by way of simple illustrative and non-limiting example and of the accompanying drawings, in which:

[0066] [ Figure 1 ] Figure 1 is a diagram of an example of an OMAMRC (Orthogonal Multiple Access Multiple Relay Channel) system according to the prior art;

[0067] [ Figure 2 ] Figure 2 is a diagram of a transmission period of a frame according to the prior art;

[0068] [ Figure 3 ] Figure 3 is a diagram of a transmission period of a frame according to the present invention;

[0069] [ Figure 4 ] Figure 4 is a diagram of an information exchange protocol between a destination and nodes (i.e., a source and a relay) according to one embodiment of the present invention;

[0070] [ Figure 5 ] Figure 5 is a simplified block diagram of a telecommunication device according to the present invention. DETAILED DESCRIPTION

[0071] exist Figure 1 In the context of the present invention, such a system comprises N nodes, which include nodes belonging to the source set and a destination d. The M sources and the set of repeaters L=NM repeaters. L≥0. N≥M≥2. When N=M, the system includes only two sources and a destination. When N>M, the system includes at least two sources and at least one repeater and a destination.

[0072] exist Figure 3 A diagram of the transmission period of a frame according to the present invention is shown in FIG. Channel usage is the minimum time-frequency resource granularity defined by the system that allows the transmission of modulation symbols. The number of channel usages is related to the available frequency band and the transmission duration.

[0073] gather Each source in communicates with a single destination with the assistance of other sources (also called user collaboration) and cooperating repeaters.

[0074] Nodes include repeaters and sources that can act as repeaters when not transmitting their own messages.

[0075] The N nodes (ie, M sources and L repeaters) access the transmission channel according to an orthogonal frequency multiple access scheme and operate according to a full-duplex mode that allows them to listen to the transmissions of other nodes without any interference.

[0076] The channel band is divided into B subbands. Each subband associated with a time slot t determines F channel usage (F resource elements). In case of transmission with OFDM modulation, a subband may comprise, for example, as many subcarriers as OFDM symbols.

[0077] Each source transmits its framed data to the destination with the help of other sources and repeaters. A frame occupies a time slot when transmitting M messages from M sources.

[0078] The transmission cycle (i.e., the transmission of frames, such as Figure 3 As shown) occurs at T+T used time slots. T≥1 is the number of transmission time slots in phase 1, where one or more subbands of the channel are allocated to each source i. used is the number of retransmission slots in phase 2, where one or more subbands of the channel are allocated to assist each selected source i, T used ≤T max , and T max is the maximum number of retransmission slots.

[0079] The determination of the sources to assist and the allocation of subbands is performed by the scheduler.The described embodiment corresponds to the case where the scheduler is hosted by the destination.

[0080] Assume that for each transmission slot and each retransmission slot, the channel is used the same number of times: B×F.

[0081] R s is a variable representing the initial throughput of source s, which can be assumed to be in the finite set The capacity of the transmission slot is N for each source i. 1,i During the first phase, each source In N 1,s The secondary channel is used to transmit messages during the period k∈{1,…,N 1,s}, where the number of times the channel is used is N 1,s Depends on the source.

[0082] The capacity of the retransmission slot is N for each source i 2 Secondary channel usage. s It represents the ratio N 2 / N 1,s A variable that can be assumed to be in a finite set The value in .

[0083] The initial throughput of the source is usually determined by the destination during an initialization phase before any transmission phase. and ratio The return is performed via a very limited throughput control channel. The initialization phase occurs at most before each transmission phase of the frame.

[0084] When T=1, it is assumed that the number of subbands is greater than or equal to the number of sources: B≥M. When T>1, it is assumed that the number of subbands multiplied by the number of transmission slots is greater than or equal to the number of sources: BT≥M.

[0085] Figure 4 An embodiment of an exchange protocol between a node and a destination is shown in FIG.

[0086] During the first phase, for T first time slots, all sources transmit on one or more subbands assigned to each source, respectively. The allocation of one or more subbands to the sources is defined in partitions, which can be determined by the destination and communicated to the sources by the destination via a control channel. When T=1, all sources transmit simultaneously on one or more subbands assigned to each source, respectively. When T>1, all sources transmit on one or more subbands assigned to each source during one or more transmission time slots. Some sources can transmit on various subbands simultaneously. For each retransmission time slot, no subband, one or more subbands are allocated to the source to be assisted.

[0087] The scheduler (ie, the destination according to the described embodiments) transmits scheduling information, which may be in the form of a vector, to the nodes. The partitioning of the sources to be assisted is determined for each subband. Thus, the partitioning can be different between each retransmission slot. Only nodes of the partition that have correct knowledge of the same source transmit the same redundancy of the same source simultaneously on one or more subbands in the same subband. These nodes include nodes that have correctly decoded the same source and the source itself; these nodes are said to be cooperative.

[0088] By way of simplification of the description, the following assumptions are then made about the OMAMRC system:

[0089] - Source and repeater are equipped with a single transmitting antenna;

[0090] - Source, repeater and destination are equipped with a single receiving antenna;

[0091] - Source, repeater and destination are fully synchronized;

[0092] - the sources are statistically independent (there is no correlation between them);

[0093] - All nodes transmit with the same maximum power P;

[0094] - Using a CRC code, assuming that the CRC code is included in the K of each source i i information bits to determine whether the message was decoded correctly,

[0095] - The links between the nodes experience additive noise and fading. In frames with a maximum duration of T+T max The fading gain is fixed when transmitting in time slots, but can vary independently from one frame to another. max ≥1 is a system parameter;

[0096] - The instantaneous quality of the reception channel / direct link (Channel State Information CSIR at the receiver) is available at the destination, source and repeater;

[0097] - Any feedback is error-free (control signals are error-free).

[0098] Use the following notation:

[0099] Nodes that intervene during phase 2 are denoted as r i , where i∈{1,…,M+L}, if i≤M, then node i is Figure 1 In the expression s source i, i∈{1,…,M}, otherwise, i>M, i∈{M+1,…,M+L}, and the node is Figure 1 Indicated as r 1 ,…,r L Repeater;

[0100] ·s t is the scheduling information. It contains the sources to be assisted for the retransmission slot t during the second phase. When it takes the form of a vector, The scheduling information has dimension B. The vector s t The i-th element s t,b Indicates the source to be assisted for the b-th subband during time slot t, b∈{1,…,B}. The vector s t The order in corresponds to the order of the subbands. The scheduling information may take other forms; the information may be in the form of, for example, an integer Q. For B subbands, the integer Q may be determined as follows: Q = p 0 +p 1 M+…+p B-1 M B-1 , where p i +1 is the identifier of the source (assuming its value is in the set {1,...,M}) associated with the i+1th band (assuming its value is in the set {1,...,B}). For example, an ordered set of three elements belonging to {0,...,9} (e.g., (1,2,3)) can be represented by the integer Q=321 or the base 10 integer 1+2×10+3×10 2 The ordered set of three elements belonging to {0,...,M-1} (for example (p 1 ,p 2 ,p 3 )) can be expressed as an integer Q = p 1 +p 2 ×M+p 3 ×M 2The form of is represented in cardinality M (there is a bijection). Thus, data of cardinality M allow identification of n-tuples whose elements are integers of the set {0, ..., M-1}. The remainder of the description considers that the scheduling information takes the form of a vector.

[0101] γ a,c is the average signal-to-noise ratio (SNR) taking into account the effects of path loss and shadowing between node a (source or repeater) and node c (source, repeater or destination).

[0102] ·h a,c is a network between node a (source or repeater) and node c (source, repeater or destination) with zero mean and variance γ a,c The path loss gain (fading) of a complex circularly symmetric Gaussian distribution; the gains are independent of each other.

[0103] ·n t ∈({0,…,B}) M+L is a vector of dimension M+L of the number of subbands for which the node is active or inactive for assisting one or more sources, which varies between 0 (node ​​is not active) and B (node ​​is active for all subbands) for retransmission time slots (time slots) t during the second phase. The vector n t The i-th element n t,i Denote the number of subbands that node i (source or repeater) is active for retransmission time slot (time slot) t, i∈{1,…,M+L}.

[0104] ·T used is the number of retransmission slots (i.e., during the second phase) that results in zero failures for all sources (the individual cutoff events for each source are zero, i.e., ):

[0105]

[0106] Examples of embodiments of the present invention

[0107] During the first phase, each source After encoding, the transmission includes K s information bits of message u s , in, is a two-element Galois field. s Includes permission to inspect messages s CRC type code for the integrity of the message. sIt is encoded according to the initial MCS. Taking into account that the initial MCS between sources may be different, the encoded message length between sources may also be different. The encoding uses incremental redundancy codes. The obtained codewords are split into redundant blocks. The incremental redundancy code can be of a systematic type; then, the information bits are included in the first redundancy. Regardless of whether the incremental redundancy code is of a systematic type, it enables the first redundancy to be decoded independently of other redundancies. For example, the incremental redundancy code can be generated by a finite series of rate-compatible punctured linear codes or a rate-free code modified to operate with a finite length: raptor code (RC), rate-compatible punctured turbo code (RCPTC), rate-compatible punctured convolutional code (RCPCC), rate-compatible low-density parity-check code (RCLDPC). According to Figure 4 In the embodiment described and illustrated in , parameter T = 1. Therefore, during the first phase, the M sources simultaneously transmit the first redundant bits of their respective messages on the allocated subbands during the transmission time slots, respectively using the modulation and coding scheme determined according to the value of the initial throughput of the source.

[0108] In each transmitted message corresponding to the source In the case of , the correctly decoded messages are assimilated with the corresponding sources for labeling.

[0109] Whether this is during the first or second phase, when a node (particularly a source) transmits, the destination and other nodes listen. Each full-duplex node can transmit on one or more subbands and simultaneously listen to all other nodes transmitting on another subband.

[0110] The destination, source, and repeater attempt to decode the message received at the end of the time slot. The success of the decoding at each node is determined by using the CRC. Thus, the destination and node determine their set of sources that have been correctly decoded.

[0111] According to this embodiment, during the second phase, for time slot (also called round) t, destination d uses, for example, the feedback broadcast control channel in the previous time slot At the end, it transmits its correctly decoded source set, t = {1,…,Tu sed}. The feedback may include an M-bit vector.

[0112] If the destination decodes all sources correctly The current cycle is stopped; a new cycle can be started. The transmission cycle of a new frame begins with the repeater and destination being erased from memory and a new message being transmitted by the source. The number of time slots (rounds) used during the second phase is T used ={1,…,T max}Depends on the success of decoding at the destination.

[0113] The set of sources that nodes, sources, and repeaters will correctly decode by the destination With its correctly decoded source set Compare and deduce from them the source set that they can assist the destination

[0114] As usual, Represented by the node The set of correctly decoded messages (or sources) at the end of time slot t (round t), t∈{0,…,T max}, including its own message for the source. The end of time slot (round) t=0 corresponds to the end of the first phase. The number of time slots used during the second phase T used ={1,…,T max}Depends on the success of decoding at the destination.

[0115] If the node set includes nodes not included in the destination set If at least one source is present in the packet, the node uses a dedicated control channel, for example of unicast type, to inform the destination accordingly. The information transmitted by the node may include the knowledge that it has correct knowledge (i.e., it has correctly decoded, including its own knowledge of the message for the source, Or Figure 4 The source set may include sources that it has correct knowledge of and that the destination has not yet correctly decoded.

[0116] During this second phase, the destination follows a specific strategy in order to select one or more sources to assist. The destination transmits a vector of sources to assist for each subband using, for example, a feedback broadcast control channel. to inform the node of the selection. The partitions of the sources to be assisted on the subbands are defined respectively.

[0117] Therefore, the destination uses the feedback channel to control the transmission of the nodes. This improves spectral efficiency and reliability by increasing the probability that the destination can decode all sources.

[0118] For each source of the partition, all nodes with correct knowledge of the source transmit the same redundancy of the same source on one or more of the same subbands for time slot t. The set of redundancy transmitted for time slot t is denoted

[0119] Nodes and destinations may improve their own decoding by exploiting the redundancy of the source for retransmissions on one or more subbands on which it did not transmit, and update their set of correctly decoded sources accordingly.

[0120] Select strategy

[0121] The selection of the source to assist for each subband depends on the channel state between the various nodes transmitting the same redundancy and the destination. The state of the channel can be assessed using mutual information as a function of the SNR of that channel / link.

[0122] By utilizing reference signals (pilot symbols, SRS signals for 3GPP LTE, etc.), the destination can determine the direct link for each subband b∈{1,…,B}: That is, the gains of the source-to-destination link and the relay-to-destination link (CSI: Channel State Information), and hence the average SNR of these links can be derived therefrom.

[0123] It is assumed that the channel statistics of each link follows a centered cyclic complex Gaussian distribution and that the statistics are independent between links. It is then sufficient to consider only the average SNR as a measure of the statistics of the link.

[0124] The signal received by the destination on subband b for retransmission slot t can be expressed as:

[0125]

[0126] in:

[0127] A i is the source s at the end of time slot t-1 i The set of nodes of correct knowledge;

[0128] h eq,Ai,t,b It is during the retransmission time slot t that A i have the same redundant version The equivalent channel generated by the transmission of all nodes on subband b is

[0129] z t,b is a complex circularly symmetric Gaussian random variable such that ( And E[|z t,b | 2 ]=2σ 2 ).

[0130] According to several embodiments, during the second phase, a vector The transmission can continue with the node having the correct knowledge of the selected and identified source to be assisted.

[0131] According to the first embodiment, at the end of time slot t-1, no node a∈A i (A i Formed with source i (ie, by source s i Transmitted message u i) knows the transmission channel h a,b The phase on subband b links it to destination d Then, the source s to be assisted on subband b i The equivalent channel can be expressed as:

[0132]

[0133] This embodiment corresponds to incoherent combining upon reception.

[0134] According to the second embodiment, at the end of time slot t-1, each node a∈A i (A i Formed with source i (ie, by source s i Transmitted message u i ) knows the transmission channel h a,b The phase on subband b links it to destination d

[0135] Upon receiving the source s to be assisted i Vector When each node a∈A i For retransmission time slot t, the transmission on the same subband b is performed by the phase factor Modulation by source s i Transmitted message u i The same redundancy of 2 = -1, and corresponds to the transmission channel h linking node a to destination d a,b The conjugate amount Divide by its norm |h a,b |, so that the node a∈A i All these redundancies of the transmission are received coherently by the destination simultaneously. i The equivalent channel is expressed as:

[0136]

[0137] This transmission mode (called “equal gain combining”) allows to obtain at the destination side a coherent combination of the set of signals transmitted by the nodes that have the i Proper knowledge of the message being transmitted.

[0138] According to a third embodiment, the set of nodes A that have correct knowledge of source i at the end of time slot t-1 is i Divide into two groups of nodes D i and E i . Each node a∈D in the first set of nodes iKnowing the transmission channel h a,b The phase on subband b links it to destination d Each node a∈E in the second group i It is not known what phase the transmission channel has on subband b that links it to destination d

[0139] Upon receiving the vector of the source to be assisted When each node a∈D in the first set of nodes i For retransmission time slot t, the transmission on the same subband b is performed by the phase factor Modulation by source s i Transmitted message u i The same redundancy of 2 = -1, and among them, corresponds to the transmission channel h linking node a to destination d a,b The conjugate amount Divide by its norm |h a,b |, so that all these redundancies transmitted by the nodes in the first group are coherently received by the destination simultaneously. In addition, i Each node transmits the signal received from source s on the same subband b for the retransmission time slot t. i Transmitted message u i The same redundancy of without phase modulation.

[0140] This embodiment may be used, for example, during transient time periods during which the destination is not yet able to determine the phase factor with all nodes. Over time, the destination can provide this information to all nodes in the system, further improving the quality of the transmission.

[0141] According to this embodiment, the equivalent channel can be expressed as:

[0142]

[0143] For all of these embodiments, the signal-to-noise ratio associated with the equivalent channel is Assumptions

[0144] Mutual information associated with equivalent channels is a function of SNR, that is

[0145] The transmission power of a node is frequency-shared across the subbands in which the node is active for the same retransmission slot and cannot exceed a maximum power P. Therefore, the mutual information associated with the equivalent channel is (where i∈{1,…,M},f∈{1,…,B}, and t∈{1,…,T max}) depends on the set A i The node j is the number of active subbands n t,j , i.e., redundancy of the same source or multiple sources is transmitted for these different sub-bands.

[0146] The selection of the source to be assisted takes into account the fact that each node that transmits a redundancy of the selected source to be assisted transmits on the allocated subbands and this is the case for the various sources to be assisted for which it has correct knowledge. The selection of the source is therefore subject to the following constraints: the transmission power of each transmitting node is distributed over the subbands on which it is active.

[0147] According to the first selection mode implemented in Algorithm 1 of the Appendix, for a retransmission time slot t, the scheduler considers all possible vectors s of size B taken from the source to be assisted t ∈{1,…,M} B , that is, these sources are taken from The vector chosen is the one that allows to provide the maximum mutual information, knowing that the mutual information depends for each subband on the equivalent channels between the various nodes transmitting the same redundancy and the destination. The best vector of the source to be assisted for subband B among these various possible vectors is as follows:

[0148]

[0149] Therefore, the optimal vector for retransmission slot t is Including mutual information The sum of all sources on subband B is the highest, where each term of the mutual information is the same as that of the same source to be assisted The error-free knowledge of each node is associated with an equivalent transmission channel established between the destination.

[0150] In other words, the destination selects the vector of sources to assist for which the average "harvested" mutual information is maximal. This average mutual information is the sum of the equivalent SNRs of each subband, so the optimization must be combined over all subbands, since the power transmitted by a node must be shared among the subbands in which the node is active.

[0151] According to the second selection mode implemented in Algorithm 2 of the Appendix, the destination selects the source to assist sequentially, subband by subband. Thus, for a retransmission time slot t, for each of the successively adopted subbands b, the destination selects from the source to assist is denoted as The source of , so that:

[0152]

[0153] Selected source for subband b is the source in the source to be assisted This source maximizes the sum consisting of, on the one hand, the sum of the mutual information of the equivalent channels of each of these subbands over subbands 1 to b-1 On the other hand, the mutual information of the equivalent channel of subband b is

[0154] The second selection mode is no more complicated than the first mode.

[0155] Of course, each selection mode is combined with the various transmission modes described above.

[0156] Figure 5 is a simplified block diagram of an embodiment of a telecommunication device DIS according to an embodiment of the present invention.

[0157] The device DIS is intended for use in an OMAMRC telecommunication system comprising N nodes including M sources s and destinations d. i (i∈{1,…,M}) and NM repeaters, N≥M≥2.

[0158] The access to the transmission channel between the node and the destination is of the orthogonal multiple access type. The exchange protocol between the node and the destination defines a maximum number of time slots per transmission frame, T+T, distributed between a first phase of T time slots and a second phase of at least one time slot, called a retransmission slot. max , 1≤T max .

[0159] The device DIS comprises at least one microprocessor μP, a memory MEM, a transmission chain EM and a reception chain RE, connected to one another by a bus Bu, the operation of which is controlled by executing a program Pg, the instructions of which allow the transmission method according to the invention to be implemented. Of course, the constituent elements of the device DIS may also be connected by means of connections other than a bus.

[0160] The microprocessor μP controls the operation of the device DIS. The memory unit MEM stores at least a program Pg for implementing a method to be performed by the processor μP according to one embodiment of the invention, and miscellaneous data such as parameters for calculations performed by the microprocessor μP, intermediate data for calculations performed by the microprocessor μP, etc. The microprocessor μP may be formed by any known and suitable hardware or software, or by a combination of hardware and software. For example, the microprocessor μP may be formed by dedicated hardware such as a processing circuit, or may be formed by a programmable processing unit such as a central processing unit, which executes a program stored in its memory.

[0161] The memory MEM may be formed by any suitable device capable of storing the program Pg or the program and data in a computer-readable manner. Examples of the memory MEM include non-transitory computer-readable storage media such as semiconductor memory devices and magnetic, optical or magneto-optical storage media loaded into the read and write units.

[0162] During initialization, the code instructions of the program Pg are loaded into a buffer memory, for example, before being executed by the processor μP. The microprocessor μP controls the individual components of the device DIS.

[0163] Thus, by executing the instructions, the microprocessor μP allows the device DIS to implement a transmission method according to one embodiment of the invention.

[0164] According to one embodiment of the present invention, the device DIS is a source of M i One of i∈{1,…,M}. According to this embodiment, the device DIS may be a mobile terminal. According to this embodiment, the device DIS is capable of transmitting frame messages. Of course, the device may transmit several messages in succession. The transmission method implemented by the device is such that it comprises an incremental redundancy type encoding implemented by an encoder of the transmission chain EM, which encoder generates several redundancies of the same message to be transmitted. The transmission performed by the device is a frequency division multiplexing type transmission on a band divided into B mutually orthogonal sub-bands, M≤BT. The method for transmitting via the device DIS further comprises:

[0165] - a first redundancy of the transmission of the message to be transmitted during phase 1, which is implemented by the transmission chain EM;

[0166] - Receive scheduling information The scheduling information indicates the selected sources for each subband that have not been correctly decoded by the destination, referred to as sources to be assisted, wherein the scheduling information takes into account the constraint of the maximum transmission power of each node, which is implemented by the receiving chain RE;

[0167] - During the retransmission slots of this phase 2, for sources for which the device has correct knowledge, a second redundancy of the message of the selected source is transmitted on the corresponding subband, this being implemented by the transmission chain EM.

[0168] By executing the instructions, the microprocessor μP checks that the transmission of the device DIS on a number of sub-bands does not exceed the maximum transmission power constraint of the device.

[0169] According to one embodiment of the invention, the device DIS corresponds to a destination d of an OMAMRC telecommunication system. According to this embodiment, the device may be a base station. The device is then intended for use in an OMAMRC telecommunication system comprising N nodes and the device acting as destination d.

[0170] Thus, by executing the instructions, the microprocessor μP allows the device DIS to implement a transmission method comprising:

[0171] - receiving M first redundancies of M messages from M sources simultaneously on at least M subbands during phase 1, which is implemented by the reception chain RE;

[0172] -Transmission scheduling information The scheduling information indicates selected sources per subband that have not been correctly decoded by the device, referred to as sources to be assisted, wherein the scheduling information takes into account a constraint on the maximum transmission power of each node, which is implemented by the transmission chain EM;

[0173] - Receiving the same second redundancy of the same selected source si on the same subband and originating from a different node having correct knowledge of the same source for the same retransmission slot of this phase 2, this is implemented by the reception chain RE.

[0174] appendix

[0175] Algorithm 1 Selection strategy

[0176] Algorithm 2 Selection strategy

[0177]

[0178]

Claims

1. A method for transmitting a framed message intended for use in a telecommunication system comprising a destination (d) and N nodes comprising M sources (s i i∈{1,…,M}) and NM relays, N≥M≥2, in, The transmission channel between the N nodes is orthogonal multiple access, and the maximum number of time slots per transmission frame distributed between the first phase of T time slots and the second phase of at least one time slot called a retransmission time slot is T+T max , 1≤T max , wherein the message of the source has been encoded before transmission according to an incremental redundancy type encoding generating a number of redundancies, the transmission being a frequency division multiplexing type transmission carried out on a band divided into B≥2 mutually orthogonal sub-bands, M≤BT, so that the method comprises: - transmitting during the first phase M first redundancies of the M messages of the M sources; and Characterized in that the method further comprises: - Receive scheduling information via these nodes The scheduling information indicates the selected sources for each subband that have not been correctly decoded by the destination, referred to as sources to be assisted, and the scheduling information takes into account the constraint of the maximum transmission power of each node; - For the same retransmission slot of this stage 2, transmit the same selected source (s i ) is called an active node, where it has the same second redundancy of the same message from the same source, where the node's transmission on several subbands is constrained by the node's maximum transmission power.

2. The transmission method according to claim 1, further comprising: include: - At the end of this phase 1 transmission slot, the source set is transmitted which is correctly decoded by these nodes.

3. The transmission method according to claim 1, further comprising: include: - receiving, via the nodes, the set of sources correctly decoded by the destination from among the sources received by the destination during the first phase; - At the end of this 1st phase, the source set that was correctly decoded by these nodes and not yet correctly decoded by the destination is transmitted via these nodes.

4. The transmission method according to any one of claims 1 to 3, in, The scheduling information is obtained by comparing the sum over subband B of the mutual information for each subband b of the equivalent channels between those nodes having correct knowledge of the same source to be assisted and the destination between the different possible scheduling information of the source to be assisted for each subband.

5. The transmission method according to any one of claims 1 to 4, in, In this scheduling information In the case of B components, these components are determined sequentially one subband after another and, for a given subband b, this component is obtained by determining the maximum of a sum between the various sources to be assisted, said sum comprising, on the one hand, the sum over subbands 1 to b-1 of the mutual information of equivalent channels between those nodes that have correct knowledge of the same source to be assisted and the destination and, on the other hand, the mutual information of equivalent channels between those nodes that have correct knowledge of the same source to be assisted and the destination for said subband b.

6. The transmission method according to any one of claims 1 to 5, in, The transmission channel of the subband b between the node a taken from the N nodes and the destination (d) is represented as Among them, h a,b is the amplitude and is the phase factor. This method makes it possible to have the same selected source (s i Each of these nodes knows the phase of the transmission channel between the node a and the destination (d). When each of these nodes is connected to the same source (s i ) is modulated by the phase factor, Among them, j 2 = -1, and among them, corresponds to the amplitude h of the transmission channel between the node and the destination (d) a,b The conjugate amount Divide by its norm |h a,b |.

7. The transmission method according to any one of claims 1 to 5, in, The transmission channel of the subband b between the node a taken from the N nodes and the destination (d) is represented as Among them, h a,d is the amplitude and is the phase factor, where the subband b has the same selected source s i The nodes having correct knowledge of are grouped into a first group of nodes and a second group of nodes, such that each node in the first group knows the phase of the transmission channel between the node and the destination (d) of the subband b And each node in the second group does not know the phase of the transmission channel between the node and the destination (d) of the subband b The method enables the source s to be sent to the node a in the first group. i The transmission of the same second redundancy is modulated by the phase factor, Among them, j 2 = -1, and among them, corresponds to the amplitude h of the transmission channel between the node a and the destination (d) a,b The conjugate amount Divide by its norm |h a,b |, and make the source s i The transmission of the same second redundancy occurs without phase correction.

8. A method for transmitting framed messages implemented by a telecommunications device and intended for a telecommunications system, the telecommunications system having N nodes and a device (d), the nodes including M sources (s i i ∈ {1,…, M}) and N - M repeaters, N ≥ M ≥ 2, in, Orthogonal multiple access transmission channel between the N nodes, wherein the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot called a retransmission time slot is T+T max , 1≤T max , wherein the message of the source has been coded before transmission according to an incremental redundancy type coding generating a number of redundancies, the transmission being a frequency division multiplexing type transmission carried out on a band divided into B mutually orthogonal sub-bands, M≤BT, so that the method comprises: - receiving, by the device during the first phase, M first redundancies of the M messages of the M sources simultaneously on at least M subbands; Characterized in that the method further comprises: - The device transmits scheduling information The scheduling information indicates selected sources per subband that have not been correctly decoded by the device, referred to as sources to be assisted, wherein the scheduling information takes into account a constraint on a maximum transmission power of each node; - The device receives the same selected source (s) on the same subband for the same retransmission slot of the second phase i ) and originates from the same second redundancy of a different node having correct knowledge of the same source.

9. The transmission method according to claim 8, further comprising: include: - the device transmits the set of sources correctly decoded by the device among the sources received by the device during the first phase; - At the end of this 1st phase, the device receives the set of sources that were correctly decoded by the nodes and not yet correctly decoded by the device.

10. A method for transmitting framed messages implemented by a telecommunication device, intended for use in a telecommunication system having N nodes and a destination (d), the nodes comprising M sources (s i i∈{1,…,M}) and NM repeaters, N≥M≥2, the device forms one of these sources, in, orthogonal multiple access to the transmission channel between the N nodes and the destination, wherein the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot called a retransmission time slot is T+T max , 1≤T max , the method comprises encoding the message before transmission according to an incremental redundancy type coding generating a number of redundancies, wherein the transmission is a frequency division multiplexing type transmission carried out on a band divided into B mutually orthogonal sub-bands, M≤BT, so that the method further comprises: - a first redundancy of messages transmitted from the source during the first phase; Characterized in that the message further includes: - Receive scheduling information The scheduling information indicates selected sources for each subband that have not been correctly decoded by the destination, referred to as sources to be assisted, wherein the scheduling information takes into account a constraint on the maximum transmission power of each node; - During the retransmission slots of this second phase, for sources for which the device has correct knowledge, a second redundancy of the message of the selected source is transmitted on the corresponding subbands, wherein the transmission of the device on several subbands is constrained by a maximum transmission power.

11. The transmission method according to any one of claims 1 to 10, in, For the same source, the first redundancy and the second redundancy are different.

12. The transmission method according to any one of claims 1 to 11, in, The scheduling information is based on the mutual information for each subband b of the equivalent channel between those nodes having correct knowledge of the same source to be assisted and the destination To be determined.

13. A telecommunication device (DIS) intended for use in a telecommunication system for transmitting framed messages, the telecommunication system comprising N nodes including M sources (s i i∈{1,…,M}) and NM relays, N≥M≥2, in, Orthogonal multiple access to the transmission channel between the N nodes and the destination, wherein the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot called a retransmission time slot is T+T max , 1≤T max , the transmission is of frequency division multiplexing type carried out on a band divided into B≥2 mutually orthogonal sub-bands, M≤BT, the device corresponding to one of these sources comprises at least one microprocessor μP, a memory (MEM), a transmission chain (EM) and a reception chain (RE), the transmission chain (EM) comprising an encoder implementing an incremental redundancy type coding generating multiple redundancies of the same message to be transmitted such that: the transmission chain (EM) is capable of transmitting a first redundancy of the message to be transmitted during the first phase; - The receive chain (RE) is capable of receiving scheduling information of size B The scheduling information indicates the selected sources for each subband that have not been correctly decoded by the destination, referred to as sources to be assisted, the scheduling information taking into account the constraint of the maximum transmission power of each node; - The transmission chain (EM) is also capable of transmitting, during the retransmission slots of the phase 2, a second redundancy of the message of the selected source on the corresponding subbands for which the device has correct knowledge, wherein the transmission on several subbands is subject to the constraint of a maximum transmission power.

14. A telecommunication device (DIS) for transmitting framed messages intended for use in a telecommunication system comprising N nodes and a destination (d), the nodes comprising M sources (s i i∈{1,…,M}) and NM relays, N≥M≥2, in, Orthogonal multiple access to the transmission channel between the N nodes and the destination, wherein the maximum number of time slots per transmission frame distributed between a first phase of T time slots and a second phase of at least one time slot called a retransmission time slot is T+T max , 1≤T max , the transmission is of frequency division multiplexing type carried out on a band divided into B≥2 mutually orthogonal sub-bands, M≤BT, the device corresponding to one of these sources comprises at least one microprocessor (μP), a memory (MEM), a transmission chain (EM) and a reception chain (RE) such that: - the receiving chain (RE) is capable of receiving simultaneously during the first phase M first redundancies of the M messages of the M sources on at least M subbands; - This transport chain (EM) is capable of transmitting scheduling information The scheduling information indicates selected sources for each subband that have not been correctly decoded by the device, referred to as sources to be assisted, the scheduling information taking into account a constraint on the maximum transmission power of each node; - The receiving chain (RE) is also capable of receiving the same selected source (s) on the same subband for the same retransmission slot of the second stage i ) and originates from the same second redundancy of a different node having correct knowledge of the same source.

15. A telecommunication system comprising a destination (d) and N nodes, the nodes comprising M sources (s i i∈{1,…,M}) and NM relays, M≥2, in, Orthogonal multiple access is used for the transmission channel between the N nodes and the destination, and the telecommunication system is suitable for implementing the transmission method according to any one of claims 1 to 12.

16. A computer program on a storage medium, the program comprising program instructions capable of implementing the method according to any one of claims 1 to 12 when the program is loaded and executed in a telecommunication device.

17. An information medium comprising program instructions capable of implementing the method according to any one of claims 1 and 12 when said program is loaded and executed in a telecommunication device.

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