FR3053550A1 - METHOD FOR ROUTING A PLURALITY OF DATA STREAMS IN A WIRELESS COMMUNICATION NETWORK - Google Patents

Abstract

The present invention relates to a method of routing a plurality of data streams in a wireless communication network (R) comprising a plurality of nodes connected by wireless communication links, the method comprising steps of: identification (101) ) of at least one group of wireless communication links of the network that would interfere with each other if they were used simultaneously to transmit data, determining (102), for each data stream, a path in the network for transmitting the data stream, each path being characterized by a set of nodes of the network, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules: the total number of nodes to be included in the paths is to be minimized; for each identified group, the capacity utilization rate of the group, by the plurality of data streams, must be less than or equal to a predetermined threshold; each stream is to be transmitted from a predetermined source node of the network to a predetermined destination node of the network; any node not receiving and receiving a stream must retransmit that stream to only one other node; the method further comprising deactivating (103) at least one node of the network that is not included in at least one of the determined paths.

Description

Holder (s): UNIVERSITE PIERRE ET MARIE CURIE (PARIS 6) Public establishment, NATIONAL CENTER FOR SCIENTIFIC RESEARCH (CNRS), UNIVERSITE PARIS-SUD.

Extension request (s)

Agent (s): REGIMBEAU.

to4) METHOD OF ROUTING A PLURALITY WIRELESS COMMUNICATION.

OF DATA STREAMS IN A NETWORK OF

FR 3 053 550 - A1

The present invention relates to a method for routing a plurality of data streams in a wireless communication network (R) comprising a plurality of nodes connected by wireless communication links, the method comprising the steps of: identification (101 ) at least one group of wireless communication links in the network that would all interfere with each other if used simultaneously to transmit data, determining (102), for each data flow, a path in the network for transmitting the data stream, each path being characterized by a set of network nodes, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules: total number of nodes to be included in the paths is to be minimized; for each identified group, the capacity utilization rate of the group, by the plurality of data streams, must be less than or equal to a predetermined threshold; each stream is to be transmitted from a predetermined source node of the network to a predetermined destination node of the network; any node which is not a recipient and which receives a flow must retransmit this flow to only one other node; the method further comprising deactivation (103) of at least one node of the network which is not included in at least one of the determined paths.

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FIELD OF THE INVENTION

The invention relates to the field of telecommunications networks, in particular wireless networks (including in particular ad hoc networks and mesh networks).

STATE OF THE ART

A wireless network includes a plurality of nodes linked together by wireless communication links.

It is well known that nodes close enough to each other in such a wireless network can lead to interference preventing proper transmission of data streams.

To reduce or even eliminate this interference in a network, it has been proposed to route different data streams using a large number of different nodes of the network. The different data streams pass through network paths that are far enough apart from each other not to create interference.

However, such a strategy has the disadvantage of increasing the energy consumption of the network. Indeed, a single active node consumes several watts, even hundreds of watts, even if it has no data to transmit or receive. The joint use of a large number of network nodes therefore consumes a great deal of energy.

STATEMENT OF THE INVENTION

An object of the invention is to route data flows in a wireless network in a manner that reduces the overall energy consumption of the wireless network.

It is therefore proposed, according to a first aspect of the invention, a method of routing a plurality of data streams in a wireless communication network comprising a plurality of nodes connected by wireless communication links, the method including steps of:

• identification of at least one group of wireless communication links in the network which would all interfere with each other if they were used simultaneously to transmit data, • determination, for each data flow, of a path in the network for transmitting the data flow, each path being characterized by a set of network nodes, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules:

o the total number of nodes to be included in the paths is to be minimized, o for each identified group, the capacity utilization rate of the group, by the plurality of data flows, must be less than or equal to a predetermined threshold, o each flow is to be transmitted from a predetermined source node of the network to a predetermined destination node of the network, o any node which is not a recipient and receiving a flow must retransmit this flow to only one other node, • deactivation of at least one node of the network which is not included in at least one of the determined paths.

The rules defined by the system of equations make it possible to obtain solution paths which have nodes in common. In other words, these rules lead to an aggregation of the different data flows to be transmitted on common nodes.

Thus, a large number of network nodes are not part of the paths determined following the resolution of the system of equations defining these rules. By deactivating these nodes in large numbers, the energy consumption consumed by the network to route the plurality of data streams is considerably reduced.

The process can be completed with the following optional features, taken alone or in combination when technically possible:

• the system of equations also defines rules indicative that network coding is to be used to transmit the data streams.

The method comprises a step of configuring at least one node of the network in which two determined paths intersect, so that the node implements network coding of the data passing through the paths that intersect.

• the solution of the system of equations is implemented by a whole number linear program.

• a group of links is a click of a conflict graph comprising vertices representing the wireless communication links of the network, and edges connecting vertices, in which an edge represents interference between the wireless communication links represented by the vertices that the edge connects.

• the resolution of the system of equations produced, for each wireless communication link and for each data flow, a boolean indicating whether the wireless communication link is to be used to transmit or not the data flow, each path being identified by a plurality of such booleans.

• the bandwidth utilization rate of a group is the sum of the capacity utilization rates of the group's links by the plurality of data flows, the capacity utilization rate of a link being a ratio between a capacity consumed on the link to transfer the plurality of data and an empty capacity of the link.

• the predetermined threshold is equal to 1.

According to a second aspect of the invention, there is also proposed a computer program product comprising program code instructions for the execution of the steps of the above method, when this program is executed by at least one processor.

It is further proposed, according to a third aspect of the invention, a device for routing a plurality of data streams in a wireless communication network comprising a plurality of nodes connected by wireless communication links, the device including:

• at least one processor configured to:

o determine at least one group of wireless communication links in the network which would all interfere with each other if the group links were used simultaneously to transmit data, o determine, for each data flow, a path in the network for transmit the data flow, each path being characterized by a set of network nodes, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules:

the total number of nodes to be included in the paths is to be minimized, for each identified group, the capacity utilization rate of the group, by the plurality of data streams, is less than or equal to a predetermined threshold, each stream is at transmit from a predetermined source node of the network to a predetermined destination node of the network, any node not being recipient and receiving a flow retransmits this flow to only one other node, • a control interface configured to control the deactivation of at least a network node which is not included in at least one of the determined paths.

Finally, there is proposed, according to a fourth aspect of the invention, a wireless communication network comprising:

• a plurality of nodes, • a plurality of wireless communication links between nodes, • at least one processor configured to:

o determine at least one group of wireless communication links in the network which would all interfere with each other if the group links were used simultaneously to transmit data, o determine, for each data flow, a path in the network for transmit the data flow, each path being characterized by a set of network nodes, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules:

the total number of nodes to be included in the paths is to be minimized, for each identified group, the capacity utilization rate of the group, by the plurality of data streams, is less than or equal to a predetermined threshold, each stream is at transmit from a predetermined source node of the network to a predetermined destination node of the network, any node not being recipient and receiving a flow retransmits this flow to only one other node, • means for deactivating at least one node of the network which does not is not included in at least one of the determined paths.

DESCRIPTION OF THE FIGURES

Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting, and which should be read with reference to the appended drawings in which:

• Figure 1 schematically shows a wireless communication network and a routing device according to an embodiment of the invention.

FIG. 2 is a flow diagram of steps of a routing method according to an embodiment of the invention.

FIG. 3 illustrates a routing of two data streams implemented by means of a method known from the prior art in an example wireless network.

• Figure 4 illustrates a conflict graph associated with the routing shown in Figure

3.

FIG. 5 illustrates a routing of two data streams implemented by means of a method according to an embodiment of the invention, in the example wireless network represented in FIG. 3.

• Figure 6 illustrates a conflict graph associated with the routing shown in Figure

5.

In all of the figures, similar elements bear identical references.

DETAILED DESCRIPTION OF THE INVENTION

Wireless network and routing device

Referring to Figure 1, a wireless communication network R includes a plurality of nodes connected by wireless communication links. Each node includes means for receiving data and means for transmitting data in a predetermined transmission area.

The network is subject to interference, of which the known model is assumed.

For example, in the case of a two-hop interference model, a given network node interferes with its neighbors and the neighbors of its neighbors, if these nodes were used simultaneously to transmit data.

By "neighbor" is meant a node which is connected directly to the given node by a wireless communication link, without this link passing through other nodes.

The network can be formally represented by a graph G = (V, E), where V is the set of network nodes and E the set of wireless communication links between these nodes. A link (t ,;) belongs to £ if t and j belong to V and if node j is in the transmission area of node t.

Interference between the different wireless communication links in the network can be represented by a second graph, conventionally called a conflict graph. The conflict graph includes vertices representing the wireless communication links of the network, and edges connecting vertices. An edge of the conflict graph represents interference between the wireless communication links represented by the vertices that the edge connects.

The wireless communication network comprises - or is associated with - a routing device 1.

The routing device 1 is one of the network nodes or a third-party device.

The routing device 1 comprises at least one processor 2, a communication interface 4 with the nodes of the network R, and a memory 6.

Processor 2 is configured to execute a computer program, which is configured to solve a system of equations, that is, to produce a solution of this system of equations.

The computer program includes an integer linear program. Such an integer linear program deals with linear equations and thus consumes the resources of processor 2 and memory 4 in reasonable quantities.

The routing device 1 can also be adapted to remotely control the activation and deactivation of the nodes of the wireless communication network. This control can typically be provided by the computer program, executed by the processor 1, with the assistance of the communication interface 4 of the device, as will be detailed below.

Alternatively, the nodes are configured to detect that they have no data to transmit, for example after a predetermined period of time. When a node detects that it has not received data to transmit within this time, it can deactivate itself.

Method for routing data flows in a wireless network

It is initially considered that all the nodes of the network are active.

The routing device 1 receives via its communication interface 4 data indicating that a plurality of data streams is to be transmitted in the network R.

It is further assumed that the source node from which each data flow comes is predetermined, as well as the destination node to where to transmit each flow (the source nodes of the different flows being potentially different, as are the destination nodes).

At this point, the paths through which to transmit data flows in the network are unknown.

With reference to FIG. 2, a routing method implemented by the routing device 1 - more specifically by the program executed by the processor 2 - comprises the following steps.

In a first step 101, the processor 2 identifies the groups of wireless communication links of the network all interfering with each other when the links of the group are used simultaneously to transmit data.

Each identified group is a click of the conflict graph of the network R. As is known in itself, a click of a graph is a subset of vertices of this graph all connected with each other, the subset being of maximum size in number of vertices which it contains.

In a second step 102, the integer linear program executed by the processor 2 determines a plurality of paths for transferring the data flows in the network (one path per flow).

Each path is characterized by a set of nodes and a set of wireless communications links.

The determination of the paths implemented by the integer linear program includes a resolution of a system of equations of which the paths are solutions.

The data produced by the integer linear program are as follows:

• For each node t of the network, a boolean x, representing the state of node i (equal to 1 if the node is used, ie if it is part of at least one of the paths, 0 if not). The set of booleans x, equal to 1 therefore represent the part of the network which will be used for the transmission of the plurality of data streams.

• For each wireless communication link (i, y) in the network, a boolean x ^f , j representing the use of the link (/, j) for the flow f (equal to 1 if the link (/, j) is used to route the flow f, 0 otherwise). The path to transmit the stream f can therefore be identified by the set of booleans x / j equal to 1.

The integer linear program is configured with the following objective function:

The above data are solutions of a system of equations solved by the integer linear program, the equations forming constraints associated with the objective function. These equations are for example previously stored in the form of code or data in a memory of the device, and read by the linear program in whole numbers with a view to their resolution.

The system of equations includes the following equations:

(1) E _(i , _nec ^ <i, vcec (2) EieKxJ - = 0, Vf EF, Vj EV - D _f } (3) Z (i, sf> EEx { _Sf = 0, Vf EF

K) Y _{Sf , i) EEXs _f i = b Vf EF (5) Σ ( _{Ο /} , 0ε £ ^ _{/ έ} = _θ- Vf EF (6) Z (i, D _f ) E _E x { _Df = 1 , Vf EF (7) Z _fEP x { _} M _f = dij, V (i, f) e E (8) <i, v / eF, vie / - {d _; } (9) vt ev Xi = (° ^{if dii = d] i =} θ 'θ ^{e E 1} kl otherwise

In these equations, the following notations are used:

• F: set of data flows to be transmitted;

• C: all of the cliques identified;

• dij: capacity (for example in bit / s) reserved on the link (/, j) for the transmission of the plurality F of streams;

• Cij: empty capacity (for example in bit / s) of the link (/, j);

• Sf: source node of the flow f;

• Df: destination node of the stream /;

• Mf: bit rate required for the transmission of stream f.

The equation (1) of the system concerns the capacity utilization rates of each click. This equation (1) sets as a rule that this rate of use must not exceed 100% (this rate can be adjusted according to the type of interference).

In equation (1) the capacity utilization rate of a group (a click) is the sum of the capacity utilization rates of the links in the group by the plurality of data flows, the utilization rate in capacity of a link being a ratio between a capacity consumed on the link to transfer the plurality of data and an empty speed of the link.

Equations (2) to (6) are representative of a principle of conservation of data flows in the network: any node receiving a flow must, if it is not the recipient, retransmit it to one of its neighbors (2), a flow cannot return to its source or leave its destination (3 and 5), a source must transmit its flow to one of its neighbors and a destination must receive a flow from one of its neighbors (equations 4 and 6).

Equation (7) is representative of a possible aggregation of several of the data streams to be transmitted if necessary via the same wireless communication link: the capacity reserved on a link is equal to the sum of the bit rates requested by each of the feed on this link.

Equation (8) states as a rule that it must be avoided that a flow can follow several paths.

Equation (9) is a condition determining whether a node is used, i.e. if it receives and / or sends traffic on one of its communication links.

The resolution of equations (1) to (9) makes it possible to obtain aggregate solution paths.

However, it may be that the implementation of these equations (1) to (9) only leads to obtaining solution paths which are unsuitable for respecting the transmission rates of the data flows, and therefore to a degradation of the quality of the applications. deployed on the network (audio or video stream for example).

The joint use of network coding is then advantageous to minimize the number of nodes used while maintaining a required level of service.

Consequently, the system of equations advantageously comprises additional equations forming indicative rules that a network coding is to be used to transmit the data streams. These additional equations are as follows:

(10) (ZfEFm { _jk ) -w _ijk = 0, e F (11) (Σολ) ε £ ^m fj _k ) “ ^x ij ^M f = e F, v / e F (12) (z _(i , ₇ -) e £ - x ^f jkM _f = 0, V (/, / c) e E, Vf e F where m { _k is the flow rate consumed by the flow f on the communication link (/, j) when k is the next node visited by the stream f and w _ijk is the overall bit rate consumed by the plurality F of streams on the link (/, j) when k is the next node visited by the stream or streams which have passed through the link (t ,;).

It should be noted that these additional equations are in synergy with the previous equations (1) to (9): indeed, beyond the advantages associated with the implementation of network coding in the network, these equations allow even better aggregated paths.

In a third step 103, the program executed by the processor 2 can command the deactivation of at least one network node which does not belong to any of the paths which have been determined at the end of the second step, via the communication interface 4.

This deactivation can for example include the sending of a deactivation message to each node concerned via the communication interface 4 of the routing device. The deactivation of a node can be a standby or extinction of this node . A standby or off node consumes at most a few milliwatts, which in itself is a first energy saving. Furthermore, such a node no longer sends information (in particular signaling) and no longer interferes with its neighborhood, further increasing this energy saving.

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In a fourth step 104, the routing device 4 configures the nodes of the network so that the data streams can be transmitted in the network via the paths previously determined. This configuration can typically include the sending by the device 1 via the communication interface 4 to the various nodes left active of the network of the routing rules indicating to each node to which other neighbor (and therefore on which link) to transmit data from. a data stream it receives.

In a fifth step 105, the data streams f are transmitted in the network via the paths determined previously.

To better highlight the advantages of the routing process thus implemented, let us take the example of the wireless communication network illustrated in FIG. 3 comprising ten nodes in which two flows are to be transmitted at the same time, from node 1 to node 5 and from node 10 to node 6, respectively.

The implementation of a routing process looking for shorter paths in number of hops leads to the determination of the paths (a) and (b) represented by two arrows.

The wireless communication links which are part of the two determined paths are the following: {(1 2), (2 3), (3 4), (4 5)} and {(10 9), (9 8), ( 8 7), (7 6)}.

It is assumed that the interference model of this network is two hops (a node interferes with its neighbors and their neighbors). The conflict graph associated with the routing implemented in FIG. 3 is that represented in FIG. 4.

This conflict graph includes five clicks at C ₅ , including the following wireless communication links:

• Ci = {(1 - -2), (2- -3), (3- -4), (4- > 5), (8- > 7)} • c ₂ = {(7 - -6), (8- -7), (9- -8), (10- -9), (3- -4)} • C ₃ = {(3 - -4), (4- -5), (8- -7), (9- > 8), (10- -9)} • C ₄ = {(2 - -3), (3- -4), (4- -5), (8- > 7), (9- > 8)} • C ₅ = {(1 - -2), (2- -3), (3- -4), (8- > 7), (7 - > 6)}

Assuming that the wireless communication links each have a total capacity of 100 units and that the data flows each require a throughput of 20 units, the click-through rates in the sense of equation (1) would be all 100%:

• Ç: 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 100% • C ₂ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 100 % • C ₃ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 100% • C ₄ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 100% • C ₅ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 100%

In this case, the bit rates required to transmit the two flows can be respected; flows could be routed via the shortest paths in number of hops without degradation of throughput. However, all nodes are active, consuming a lot of energy.

By applying the method of the invention to this same network, the paths determined are those shown in FIG. 5. These two paths do not request the nodes 7, 8 and 9 (which are therefore put on standby or switched off).

The wireless communication links included in the determined paths are the following: {(1 - + 2), (2 - + 3), (3 - + 4), (4 - + 5)} and {(10 -> 5), (5 -> 4), (4 -> 3), (3 -> 2), (2 -> 1), (1 -> 6)}.

The energy consumption of the network when this routing is implemented is therefore reduced compared to the routing according to FIG. 3.

The determination of the preceding paths and the deactivation of the nodes not used for the routing of the data flows leads to the conflict graph represented in FIG. 6. The clicks of this different conflict graph are then as follows:

Ci = {(1 - > 2), (2- > 3), (3— > 4), (4- > 5), (3- > 2), (4- > 3), (2- + 1)} c ₂ = {(2 - > 1), (3- > 2), (4- > 3), (5— > 4), (2- > 3), (3- > 4), (4- + 5)} C ₃ = {(1 - > 6), (2- > 1), (3- > 2), (4- > 3), (1 - > 2), (2- > 3), (3- + 4)} C ₄ = {(10- -5), (3- -4), (4- -5), (3- -2), (4- -3), (5- - + 4)}

If equation (1) and additional equations (10) to (12) were not taken into account during the determination of the paths, the click-through rates would be:

• Ç: 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 140% • C ₂ : 20/100 + 20/100 + 20/100 + 20 / 100 + 20/100 + 20/100 + 20/100 = 140% • C ₃ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 140 % • C ₄ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 = 120%

The network is then saturated.

Equation (1) must therefore be taken into account so as not to saturate the network, but to respect it in the example considered, the transmission transmission rates should not exceed 14.28 in order not to overload the clicks:

• Ç: 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 = 99.96 (- 100%) • C ₂ : 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 = 99 .96 (-100%) • C ₃ : 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 +14.28 / 100 = 99.96 (-100%) • C ₄ : 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 + 14.28 / 100 = 85.68%

Energy consumption is therefore reduced, but to the detriment of the quality of the applications deployed.

By associating aggregation and network coding, i.e. taking into account all the equations defined above (not only equations (1) to (9) but also equations (10) to (12 )), nodes 2, 3 and 4 can reduce their number of transmissions by combining the data received on their various input links.

Network coding works in the following way in the example shown in Figure 5.

Node 1 sends first data (belonging to a first stream) to node 2, and stores it temporarily.

Node 3 sends second data (belonging to a second stream) to node 2, and stores it temporarily.

Node 2 receives from node 1 the first data from the first flow, and also receives from node 3 second data from the second flow.

Node 2 combines the first data and the second data. This combination and for example a bitwise sum by means of the operator XOR; However, other combinations are possible.

Node 2 transmits this combination to each of nodes 1 and 3. As the network is a wire network, the node actually only implements a single multidirectional transmission of data, this data being able to be picked up by neighboring nodes 1 and 3 which are in range.

Node 1 receiving the calculated combination can find the value of the second data by combining the received combination with the first ones it had memorized.

In the case of the sum with operator XOR, the node 1 can find the second data by carrying out in its turn a sum XOR bit by bit of the combination received with the first data which it had memorized.

Similarly, node 3 receiving the calculated combination can find the value of the first data by combining the received combination with the second that it had stored.

The same network coding is also implemented by nodes 3 and 4.

It is thus understood that network coding makes it possible to reduce the number of transmissions to be carried out to transmit the same volume of data in the wireless network, thereby increasing the bit rates.

Under these conditions, to take the example above, in which it was considered that the streams should be transmitted with a bit rate of 20 units, the clicks utilization rates with implementation of network coding become:

• Ç: 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100

- (20/100 + 20/100) * = 100% • C ₂ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100

- (20/100 + 20/100) * = 100% • C ₃ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100

- (20/100 + 20/100) * = 100% • C ₄ : 20/100 + 20/100 + 20/100 + 20/100 + 20/100 + 20/100

- (20/100) * = 100%

In the numerical example calculations set out above, the terms with an asterisk (*) represent the capacity recovered thanks to network coding limiting the number of transmissions.

In conclusion, taking network coding into account in the equations solved by the integer linear program thus allows the deactivation of 30% of the nodes, while guaranteeing the rates required by the flows and respecting the network capacity.

As indicated previously, the routing device can quite well be itself a node of the network.

It can for example be provided that each node of the network implements the routing process, and deactivates itself if it comes to the conclusion that it is not itself part of one of the paths that it has determined. A node can also deactivate other nodes on the network.

Claims (11)

1. A method of routing a plurality of data streams in a wireless communication network (R) comprising a plurality of nodes connected by wireless communication links, the method comprising steps of: • identification (101) of at least one group of wireless communication links in the network which would all interfere with each other if they were used simultaneously to transmit data, • determination (102), for each data flow, of a path in the network to transmit the data flow, each path being characterized by a set of nodes of the network, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules: o the total number of nodes to be included in the paths is to be minimized, o for each identified group, the capacity utilization rate of the group, by the plurality of data flows, must be less than or equal to a predetermined threshold, o each flow is to be transmitted from a predetermined source node of the network to a predetermined destination node of the network, o any node which is not a recipient and receiving a flow must retransmit this flow to only one other node, • deactivation (103) of at least at least one node of the network which is not included in at least one of the determined paths. 2. Method according to the preceding claim, wherein the system of equations further defines rules indicative that a network coding is to be used to transmit the data streams. 3. Method according to the preceding claim, comprising a configuration step (104) of at least one node of the network in which two determined paths intersect, so that the node implements a network coding of the data passing through the paths which cross. 4. Method according to one of the preceding claims, in which the resolution of the system of equations is implemented by an integer linear program. 5. Method according to one of the preceding claims, in which a group of links is a click of a conflict graph comprising vertices representing the wireless communication links of the network, and edges connecting vertices, in which an edge represents interference between the wireless communication links represented by the vertices that the edge connects. 6. Method according to one of the preceding claims, in which the resolution of the system of equations produces, for each wireless communication link and for each data stream, a boolean indicating whether the wireless communication link is to be used for whether or not to transmit the data stream, each path being identified by a plurality of such Booleans. 7. Method according to one of the preceding claims, in which the bandwidth utilization rate of a group is the sum of the capacity utilization rates of the links of the group by the plurality of data streams, the rate of capacity utilization of a link being a ratio between a capacity consumed on the link to transfer the plurality of data and an empty capacity of the link. 8. Method according to one of the preceding claims, in which the predetermined threshold is equal to 1. 9. A computer program product comprising program code instructions for executing the steps of the method according to one of the preceding claims, when this program is executed by at least one processor. 10. Routing device (1) of a plurality of data streams in a wireless communication network comprising a plurality of nodes connected by wireless communication links, the device comprising: • at least one processor (2) configured to: o determine at least one group of wireless communication links in the network which would all interfere with each other if the group links were used simultaneously to transmit data, o determine, for each data flow, a path in the network for transmit the data flow, each path being characterized by a set of network nodes, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules: the total number of nodes to be included in the paths is to be minimized, for each identified group, the capacity utilization rate of the group, by the plurality of data streams, is less than or equal to a predetermined threshold, each stream is at transmit from a predetermined source node of the network to a predetermined destination node of the network, any node not being recipient and receiving a flow retransmits this flow to only one other node, • a control interface (4) configured to control the deactivation of 'at least one node of the network which is not included in at least one of the determined paths. 11. Wireless communication network (R) comprising: • a plurality of nodes, • a plurality of wireless communication links between nodes, • at least one processor (2) configured to: o determine at least one group of wireless communication links in the network which would all interfere with each other if the group links were used simultaneously to transmit data, o determine, for each data flow, a path in the network for transmit the data flow, each path being characterized by a set of network nodes, the determination comprising a resolution of a system of equations whose paths are solutions, the system of equations defining the following rules: the total number of nodes to be included in the paths is to be minimized, for each identified group, the capacity utilization rate of the group, by the plurality of data streams, is less than or equal to a predetermined threshold, each stream is at transmit from a predetermined source node of the network to a predetermined destination node of the network, any node not being recipient and receiving a flow retransmits this flow to only one other node, • means (1, 4) for deactivating at least one node of the network which is not included in at least one of the determined paths. 1/4