SYSTEM AND METHOD FOR TRANSMITTING DATA

• US 20170339045A1
• Filed: 05/17/2017
• Published: 11/23/2017
• Est. Priority Date: 05/20/2016
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: BOUYSSOUNOUSE, Guy, PEREZ, Frdric, DELATTRE, Michel
• Granted Patent: US 10,454,813 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 47/365 Dynamic adaptation of the packet size
• CPC Class Codes: H04L 47/38 by adapting coding or compression rate
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

A method and a system are provided implementing a mechanism for relaying by all the nodes, on all the networks and sub-networks connected and defined by the routing directive: as soon as a number of cells “n” of different index have been received, whatever the sender thereof, making it possible to reconstruct the message and until, on each of the sub-networks, a predefined number of cells of different index has been sent or received. The relaying comprises decoding the message received and recoding it by a sequence of the unique fountain code on each sending of the same message whatever the relay node.

Claims

1. A method for transmitting a message M sent by a source node within a group of nodes each linked to one or more broadcasting sub-networks, at least one relay node between these broadcasting sub-networks and a routing protocol, a message consisting of n cells and comprising information specific to the routing wherein:

at the level of the source node;

choosing a coding of the cells of a message M and of the information specific to the routing, by the source node by using a fountain code adapted for generating n+k cells, so as to constitute p ranges of x cells, with x greater than or equal to n, a cell being tagged by an index in the message,

as a function of routing directives and of its identifier IDn, the source node determines the ranges of x cells to be used to code the message before the sending to the relay node or nodes or to the recipient node or nodes,

the source node groups together the cells to be transmitted into several segments, a segment comprises a number Ns of coded cells and the source node inserts before each segment a header comprising at least the following information;

an item of information making it possible to deduce the index of each cell contained in the segment, an identifier specific to the message to be transmitted and its size,

sending at least one first string of segments {S₁₁(M), . . . , S_1k(M)} of the message M via a first transmission path and at least one second string of segments {S₂₁(M), . . . , S₂₁(M)} of the message M via a second transmission path, at the level of a relay node;

the relay node keeps count per message M and per sub-network SR of the cells of different indices that it sends and that it receives from the other nodes of the sub-network, on the basis of the message identifier contained in the segment header,

as soon as the relay node has at its disposal a number of cells of different indices corresponding to the size of the message M, it reconstructs this message,

as a function of the routing directives contained in the reconstructed message and of its node identifier IDn, the relay node determines the ranges of x cells to be used to recode the message before the sending to the other relay nodes or to the other recipient nodes, and sends on each sub-network a maximum number of cells while taking account of the cells that it has already received on this sub-network,

the relay node stops its sending on the sub-network SR as soon as the number of cells of different indices received and sent on the sub-network makes it possible to reconstruct the message from the other nodes of the sub-network under the assumption of nominal reception,

the recipient nodes belonging to the group of linked nodes and which are not relay nodes reconstruct the message on the basis of segments received from the sub-networks to which they are attached before delivering the message.

2. The method according to claim 1, wherein the algorithm for coding the cells is an algebraic code.

3. The method according to claim 1, wherein the number of cells is chosen as a function of the characteristics of the sub-network for transmitting the message.

4. The method according to claim 1, wherein the number of cells to be transmitted on a sub-network corresponds to the number adapted for the error rate of the transmission sub-network.

5. The method according to claim 1, wherein it uses a function for allocating range of cells to be sent which is adapted for allocating a different range to each (node, sub-network) pair, the sub-networks to be considered being the sub-networks of the routing directive.

6. The method according to claim 1, wherein the controlling of the transmission of the segments takes account of a reception state item of information delivered by the receivers.

7. The method according to claim 1, wherein the transmission of the data is carried out by high-frequency transmission and/or very-high-frequency transmission and/or all IP network transmission.

8. A system for relaying one or more messages within a network comprising several nodes communicating with one another by means of a broadcasting medium, and belonging to a group G, comprising at least the following elements:

a source node of message M to be transmitted on several paths corresponding to at least two sub-networks, the source node comprising at least one processor adapted for executing the steps of the method according to claim 1, a coding algorithm for the data of the message M to be transmitted,

one or more relay nodes each comprising a sender, a receiver, a coding/decoding algorithm for the message M identical to the algorithm for coding the source node, a counter of the cells contained in the coded message that are sent and received per forwarding path of the message M, the coding/decoding algorithm being adapted for the recombining of elements transmitted on various sub-networks, a receiver adapted for receiving the message sent by the source node, a processor adapted for reconstructing the message M, for recoding it on the basis of the information and for transmitting it to a recipient node and for stopping the sending as soon as the number of cells of different indices received and sent on the sub-network makes it possible to reconstruct the message from the other nodes of the sub-network under the assumption of nominal reception.