GB2555445A

GB2555445A - Multi-copy data transmission with rate adaptation

Info

Publication number: GB2555445A
Application number: GB1618227.1A
Authority: GB
Inventors: Lorgeoux Mickaël; Le Houerou Brice
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2016-10-28
Filing date: 2016-10-28
Publication date: 2018-05-02
Anticipated expiration: 2036-10-28
Also published as: GB201618227D0; GB2555445B

Abstract

In a communication system 100, at least one full copy of a set of data packets is transmitted from a source device 101 to a sink device 102 via at least two routes RT. Each route comprises at least one wireless path, and the capacity of each route to transmit the data is determined based on the transmission conditions of these paths. Where a selection of routes can each only offer part of the required capacity, a single full copy of the data packets is distributed amongst them for complementary transmission. The system is directed for use in wireless multi-hop networks which use the 60 GHz bandwidth. Each route may have a transmission budget, which relates to its share of the overall time available to transmit data over the network. A selection of routes may be chosen for multi-path, multi-copy data transmission, the selection depending on the number of wired and wireless paths in each route, and considerations about spatial diversity.

Description

(54) Title of the Invention: Multi-copy data transmission with rate adaptation

Abstract Title: Multi-path multi-copy data transmission in a wireless multi-hop network where a single copy may be divided over multiple paths (57) in a communication system 100, at least one full copy of a set of data packets is transmitted from a source device 101 to a sink device 102 via at least two routes RT. Each route comprises at least one wireless path, and the capacity of each route to transmit the data is determined based on the transmission conditions of these paths. Where a selection of routes can each only offer part of the required capacity, a single full copy of the data packets is distributed amongst them for complementary transmission. The system is directed for use in wireless multi-hop networks which use the 60 GHz bandwidth. Each route may have a transmission budget, which relates to its share of the overall time available to transmit data over the network. A selection of routes may be chosen for multi-path, multi-copy data transmission, the selection depending on the number of wired and wireless paths in each route, and considerations about spatial diversity.

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TITLE OF THE INVENTION

MULTI-COPY DATA TRANSMISSION WITH RATE ADAPTATION

FIELD OF THE INVENTION

The invention relates to the field of determining a transmission scheme of data packets in a communication system.

The background of the invention relates to radio communication links between two stations over a “multi-hop” network or “communication system”, in particular, wireless multi-hop networks established using the 60 GHz (Gigahertz) radio bandwidth, for example in a mixed reality system.

A wireless 60 GHz network has a radio bandwidth with a large amount of spectral space (up to 7 GHz), which is of interest for short distance MultiGigabits data rate wireless communications. Such communications are not achievable by wireless local area network (WLAN) standard devices limited to 2.4 GHz and 5 GHz radio bands. The radio bandwidth of the 60 GHz network enables applications requiring gigabit data rates such as for quasi lossless compressed video streaming (between 150 Mbps - megabits per second - and 1 Gbps - gigbits per second) and 1 Gbps file transfer.

The Wireless LAN Medium Access Control (MAC) and Physical LAYER (PHY) Specifications 802.11ad released by the IEEE STANDARDS ASSOCIATION 802.11 2012, in particular Amendment 3: Enhancements for Very High Throughput in the 60GHz Band, defines a standard for 60 GHz communication devices to communicate over 60 GHz unlicensed radio band by describing ’Medium Access Control’ MAC and 'Physical Layer’ PHY specification requirements.

Nevertheless, 60 GHz communications have a link budget issue due to the high path loss inherent to high frequency bands. The wave propagations in 60 GHz are significantly different from those of 2.4 GHz and 5 GHz signals. A 60 GHz wireless propagation is subject to a path loss at least 20 dB (decibels) worse than that of 5 GHz signal propagation. In order to achieve an efficient communication with MultiGigabit performance up to several meters distance, 60 GHz communication devices need to use high gain directional antennas to compensate for attenuation.

Due to shorter wavelengths at 60 GHz, compact directional antenna arrays can be implemented to support beam steering. The amendment 802.11ad defines a specific communication protocol termed “Directional MultiGigabits” or DMG, which is applicable to millimeter wave communications only. The DMG protocol allows high data rate communication modes to be established, achieving up to 7 Gbps data rate transmissions DRT, by simultaneously controlling the beamforming of the transmitter antenna and of the receiver antenna.

In practice, the achievable data rate transmission between two stations will vary from 7 Gbps to 25 Mbps over a distance of approximately ten meters for indoor applications. Consequently, the achievable data rate transmission may vary inadvertently over time, depending on distance and/or change in the environment.

For a station moving at the speed of a user walking (such as a user carrying a cellular phone), the achievable data rate transmission is adapted over time using a data rate transmission selection method in order to obtain a low packet error rate PER (set at 1% in the amendment 802.11 ad) for the upper layer to the MAC.

The use of directional antennas renders 60 GHz communications highly directional and thus highly sensitive to shadowing issues. That is to say, an object or a living organism such as a human positioned in the line of sight between two 60 GHz devices can easily interrupt a communication. High attenuation (from a few dB to 30 dB) thus results, with unpredictable data transfer interruption between two stations.

Figure 1 is a graph-based representation of a multi-hop network or “communication system” 100 used to establish an end-to-end application data transmission from a source station to a sink station. The network comprises a plurality of stations or devices, here 101 to 106, able to exchange data packets.

Station 101 is a source station or “source device”, station 102 is a sink station or “sink device”, and the other stations 103 to 106 are intermediate stations or “extender devices” used to establish paths Pxy, either wired or wireless between the stations, and routes RTn (wherein x is an index relating to one end of the path - here 1 to 6, according to the last number of the station; y is an index relating to the other end of the path - again 1 to 6, according to the last number of the station; and n is an index relating to the number of routes). A route RTn comprises one or more paths between the source station 101 and the sink station 102.

The network 100 thus comprises the paths P12, P13, P15, P16, P34, P42, P52, P56, P62. The paths P13, P34, P42 form an indirect route RT1. The path P12 forms a direct route RT2. The paths P15, P52 form an indirect route RT3. The paths P16, P62 form an indirect route RT4. The paths P15, P56, P62 form an indirect route RT5. The paths P16, P56, P52 form an indirect route RT6.

The different routes are alternatives allowing an application data copy to be transmitted from the source station 101 to the sink station 102. All or some paths are wireless (radio) paths established by using a same radio channel. For example, the paths P12, P13, P15, P16 directly from the source station 101 are wireless (radio) paths and the other paths P34, P42, P52, P56, P62, in particular those directly to the sink station 102, are wired paths. As the wireless paths are subjected to shadowing, a route RT comprising such a path can be interrupted such that at any given time, one or more routes may be unavailable.

A multi-path multi-copy data transmission method may thus be implemented, wherein a time period is allocated to each station to access the wireless medium with the aim of guaranteeing that at least one copy of the data packets of the application stream will arrive at the sink station 102.

However, the allocated time periods may be insufficient to transfer a copy of the application stream due to inadvertent data rate transmission changes performed by wireless controllers independently of the application data rate, as explained above. An “overflow” or an “underflow” may result during a copy data transfer of the application stream over a given path and thus route, wherein an overflow indicates that more data is to be sent than the route can handle, and an underflow indicates that the route can handle more data than is to be sent.

Different conventional methods may be used to optimize a data transmission method.

A first method consists of providing a single copy of a data packet over a single path. With respect to Figure 1, an end-to-end path is selected using tree-based routing and path selection as defined by the standard IEEE 802.11s. A single copy of the data is then transmitted over the selected path from the station 101 to the station 102. However, when shadowing occurs, path disruption with lost data packets results. In order to seamlessly recover lost data packets, multi-copy data transmission is required.

A second method thus consists of providing multiple copies of a data packet over multiple paths with a selection of reliable paths. Again with respect to Figure 1, multiple copies of data packets of the application stream are transmitted over different routes from the source station 101 to the sink station 102. Nevertheless, the issue of inadvertent data rate transmission change of each route may still occur, with possible congestion between the transmissions of the multiple copy data packets, since the wireless medium access is shared by different stations, taking more time to transmit over one path will impact data transmission on the other paths. Thus, a degradation of the bandwidth on one path will require more time to successfully transmit a copy of the data on that path, as well as to successfully transmit other copies on other paths. Congestion also causes packets to be lost, as data packets that cannot be transmitted are dropped, with the result that the multi-copy multi-path data transmission is no longer efficient and the transmission can still be disrupted by the 60 GHz shadowing issue.

A third method is based on packet routing performed successively by each station over the wireless path. Again with respect to Figure 1, the station 105 has different possibilities for the transmission of a data packet received from the station 101 to the 102 (if path P52 is implemented) directly or indirectly via the station 106. The next path is thus chosen locally by the station in charge of transmitting a received packet. Nevertheless, this method also does not prevent packets from being lost due to 60 GHz shadowing such that a station is unable to forward a received data packet.

It may therefore be desired to provide a multi-path multi-copy data transmission scheme allowing the unpredictable shadowing phenomena to be overcome.

SUMMARY OF THE INVENTION

The present invention has been devised to address at least one of the foregoing concerns.

Embodiments of the invention relate to a method of determining a transmission scheme of at least one full copy of a set of data packets to be transmitted from a source device to a sink device by means of at least two routes of a communication system, each route comprising at least one wireless path, the method comprising the steps of:

determining for each route, based on transmission conditions of its wireless paths, its capacity to transmit at least one complete copy of the set of data packets;

determining, based on the capacities of the routes, whether at least one complete copy can be transmitted; and if the response is yes, then distributing the set of data packets amongst the routes for complementary transmission of the at least one complete copy of the data packet.

According to one embodiment, the method further comprises a step of obtaining input parameters comprising:

transmission budgets available for all the routes, a transmission budget relating to a percentage of the overall time available to transmit data over the network; and an application data rate relating to a data rate required to transmit the data packets over the physical layer.

According to one embodiment, the method further comprises a step of estimating a data rate transmission to be used by each route, the data rate transmission depending on the physical data rates of the one or more wireless paths composing the route.

According to one embodiment, the method further comprises a step of selecting routes among the routes of the communication system for a multi-path multicopy data transmission.

According to one embodiment, the selection of the routes depends on at least one of the following selection criteria:

the routes having the highest number of wired paths; the routes having the highest data rate transmissions; the routes that have already performed data set transmissions; the routes comprising a minimum number of wireless paths; and/or the routes with the least paths in common.

According to one embodiment, the method further comprises a step of determining, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate.

According to one embodiment, the distributing step further comprises the steps of:

determining a number of packets to be transmitted over each selected route; determining which packets of the set of data packets will be transmitted by each selected route; and establishing a transmission sequence of the data packets.

According to one embodiment, the method further comprises a step of determining, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate; and wherein the number of packets to be transmitted over a route is proportional to the ratio associated with the route.

According to one embodiment, the distributing step comprises transmitting data packets of the set over a route of the communication system, and transmitting other data packets of the set over another route.

According to one embodiment, in response to the transmission of at least one full copy, the method further comprises:

updating, for each selected route, its ratio;

determining that only a partial copy of the set of data packets can be transmitted;

determining, for each packet of the set, a number of copies previously transmitted over the selected routes;

selecting for transmission a packet with a lower number of copies; and transmitting the selected packet over a selected route.

Embodiments of the invention also relate to a source device in a communication system further comprising at least one sink device, the source device being configured to determine a transmission scheme of at least one full copy of a set of data packets to be transmitted to the sink device by means of at least two routes of the communication system, each route comprising at least one wireless path, the source device being configured to:

determine for each route, based on transmission conditions of its wireless paths, its capacity to transmit at least one complete copy of the set of data packets;

determine, based on the capacities of the routes, whether at least one complete copy can be transmitted; and if the response is yes, then distribute the set of data packets amongst the routes for complementary transmission of the at least one complete copy of the data packet.

According to one embodiment, the device is further configured to obtain input parameters comprising:

transmission budgets available for all the routes, a transmission budget relating to a percentage of the overall time available to transmit data over the communication system; and an application data rate relating to a data rate required to transmit the data packets over the physical layer.

According to one embodiment, the device is further configured to estimate a data rate transmission to be used by each route, the data rate transmission depending on the physical data rates of the one or more wireless paths composing the route.

According to one embodiment, the device is further configured to select routes among the routes of the communication system for a multi-path multi-copy data transmission.

According to one embodiment, the device is further configured to select the routes depending on at least one of the following selection criteria:

According to one embodiment, the device is further configured to determine, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate.

According to one embodiment, the device is further configured to: determine a number of packets to be transmitted over each selected route; determine which packets of the set of data packets will be transmitted by each selected route; and establish a transmission sequence of the data packets.

According to one embodiment, the device is further configured to determine, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate; and wherein the number of packets to be transmitted over a route is proportional to the ratio associated with the route.

According to one embodiment, the device is further configured to perform the distribution by transmitting data packets of the set over a route of the communication system, and transmitting other data packets of the set over another route.

According to one embodiment, wherein in response to the transmission of at least one full copy, the device is further configured to:

update, for each selected route, its ratio;

determine that only a partial copy of the set of data packets can be transmitted;

determine, for each packet of the set, a number of copies previously transmitted over the selected routes;

select for transmission a packet with a lower number of copies; and transmit the selected packet over a selected route.

BRIEF DESCRIPTION OF THE DRAWINGS

Other particularities and advantages of the invention will also emerge from the following description, illustrated by the accompanying drawings, in which:

Figure 1, previously described, is a graph-based representation of a multi-hop network used to establish an end-to-end application data transmission from a source station to a sink station;

Figures 2A, 2B are a flow chart of a method of determining a multi-path multicopy data transmission scheme according to embodiments of the invention and a list of routes classed according to transfer ratios respectively;

Figures 3A, 3B, 3C, 3D are schematic diagrams of a multi-path multi-copy data transmission scheme determined for different routes according to embodiments of the invention; and

Figure 4 schematically illustrates a configuration of a station implemented in the system.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention relate to adapting a multi-copy data transmission scheme of a multi-hop network communication, taking into account the different data transmission rates of each route and an allocated transmission budget (TXB or “transmission budget” in the following) for the multi-copy multi-path transmit operation. An allocated time duration TD is a ratio of the overall time available for all routes divided by the number of routes, thus the amount of time to access the network over a given route to perform a data transmission, and is expressed as a percentage.

The multi-path corresponds to the use of different routes to establish a data copy transmission from the source station to the sink station. A path is a direct link between two stations. A route is composed of successive paths allowing data to be conveyed from the source station to the sink station, and also corresponds to “multihop networking”. The intermediate stations used to create different paths operate as relays.

The multi-path data transmission is performed by transmitting data over the different possible routes to establish a data transfer between the source station and the sink station. The source station is requested to use a limited transmission budget to perform the data transmission to the sink station, which is particularly relevant when several source stations need to access a shared medium. The limited transmission budget is used to transmit a maximum number of copies using multiple routes so as to favor spatial diversity.

The aim is to maximize the number of data copies transmitted without exceeding the allocated transmission budget TXB, which is split into the time durations TD to be used on each route to perform a transmission sequence. The routes are considered to be equally usable by the source station to transmit the data to the sink station to overcome the shadowing issue. Consequently, the time durations TD are equal.

Nevertheless, in another embodiment, the time durations TD are adjustable to optimize the transmission of at least a data stream copy over the concerned routes.

For each time duration TD, a ratio Tn (wherein n is the index of the route) is estimated between the application data rate ADR and the data rate transmission DRT achievable over the route.

The present invention consists in combining the usable bandwidths over the different routes and, by applying a complementary data set transmission, increasing the number of copies transmitted over the network.

In one embodiment, two distinct dedicated modules are introduced: a Multistream manager module and a stream controller module associated with each source station that transmits a data stream over the wireless network. The multi-stream manager manages bandwidth/resources allocation between data streams by means of control messages exchanged with each stream controller, which then periodically sends robustness metrics to the multi-stream manager. The multi-stream manager is thus able to compute and send a transmission budget for each stream controller. Several iterations of sending robustness metrics and updating transmission budgets may then be performed so as to obtain robustness metrics greater than a predetermined threshold for all data streams within the wireless network.

The number of routes available should be sufficient to support path diversity in order to overcome the shadowing issue of 60 GHz communications. Typically, two to four routes should be considered for establishing a multi-path multi-copy data transmission able to overcome the shadowing issue.

Embodiments of the present invention thus aim to address the problem of establishing a multi-path multi-copy data transmission scheme considering the shadowing phenomena when routes comprise at least one radio path sharing a same radio channel. In particular, a ratio Tn is determined between the application data rate ADR and the data rate transmission DRT achievable over each route.

The wired paths are not integrated in the estimation of the ratio Tn because the shadowing phenomena only impacts wireless paths.

Figure 2A is a flow chart of a method 200 of determining a multi-path multicopy data transmission scheme according to embodiments of the invention. The method 200 comprises the steps 201 to 209, and is preferably an algorithm implemented by a source station (101) performing multi-path multi-copy transmission.

In step 201, the source station 101 obtains input parameters, in particular a transmission budget TXB available for all the routes and an application data rate ADR.

The transmission budget TXB is an input parameter of the algorithm to define the multi-path multi-copy transmission scheme, and is expressed as a percentage % of the overall time available to transmit data over the shared network 100. The transmission budget TXB may be determined as evoked above, wherein a multi-stream manager module determines/updates transmission budgets based on robustness metrics received from at least two stream controller modules.

The application data rate ADR is defined as the equivalent data rate required to transmit the application data stream over the physical layer, taking into consideration the different network overheads (in particular encapsulation and medium access efficiency). As an example, a video compressed stream of 300 Mbps can require an application data rate ADR equal to 430 Mbps with a medium access efficiency of 70%, due to the MAC/PHY layer overheads for transmitting the data application over the network.

For a route comprising only one wireless path, the data rate transmission DRT is equal to the physical PHY data rate (Modulation Coding Scheme - MCS) of the wireless path.

For a route comprising a plurality of wireless paths, the data rate transmission DRT is estimated according to the different PHY data rates (MCS) of the wireless paths. The data rate transmission DRT is equal to the product of the different MCS of each wireless path divided by the sum of products of the different data transmission MCS:

DRT = product(MCS(j), j=1, j=N)/[sum(product(MCS(j), j=1, j=N with j#k)), k=1, k=N] wherein each product is from j equals 1 to N, and the sum is from k equals 1 to N, N being the number of paths of the given route, MCS(j) being the physical PHY data rate (Modulation Coding Scheme - MCS) of each wireless path j from 1 to N, and j and k are path indices from 1 to N.

For example, considering a route comprising three successive wireless paths having a respective physical PHY data rates MCS of 1 Gbit/s, 2 Gbit/s and 3 Gbit/s, the data rate transmission of the route is:

DRT = (1 x 2 x 3) / (2x3 + 1x3 + 1x2) = 0.545 Gbits/s.

Again, wired paths are not taken into account for the determination of the data rate transmission DRT, since the shadowing phenomena only impacts the wireless paths.

In step 202, the source station estimates the data rate transmission DRT to be used by each route, as described just above. First, the scheme MCS is estimated for each radio (wireless) path composing a route. This estimation is provided by each station transmitting over each path. For example, the estimation is performed by using the channel measurement feedback as defined in the standard (IEEE STANDARDS ASSOCIATION 802.11 2012, Part 11: Wireless LAN Medium Access Control (MAC) and Physical LAYER (PHY) Specifications 802.11 ad, Amendments: Enhancements for Very High Throughput in the 60GHz Band).

For example in the above standard, the channel measurement feedback can be used to determine the most appropriate scheme MCS taking into consideration a low packet error rate (for example less than 1% at the physical layer). Alternatively, the packet error rate PER is determined by counting the number of missing acknowledgement messages transmitted by a receiver to the transmitter for each transmitted data packet, allowing the highest scheme MCS satisfying a data transfer with a low packet error rate criteria (for example lower than 1% at the physical layer) to be selected. In conventional approaches, if the packet error rate satisfies the criteria, the scheme MCS is increased. If the packet error rate does not satisfy the criteria, the scheme MCS is decreased until the criteria are satisfied.

For example, with reference to Figure 1, the station 103 estimates the scheme MCS to be used over the path P34 to deliver data packets to the station 104.

In step 203, the source station 101 selects some routes to establish the multipath multi-copy data transmission. The number of selected routes should be sufficient to provide spatial diversity in order to overcome the shadowing issue of 60 GHz communications. Typically, two, three, or four routes should be considered for establishing a multi-path multi-copy data transmission. The number of routes to be used is a robustness criterion to overcome radio path disruption due to 60 GHz shadowing phenomena.

The possible selection criteria are:

- the routes having the highest number of wired paths;

- the routes having the highest data rate transmissions DRT are selected, such that the number of transmitted copies is maximized;

- the routes that have already performed data set transmissions are selected, such that the risk of radio path disruption is reduced;

- the routes comprising a minimum number of radio (wireless) paths are selected, such that the risk of radio path disruption is reduced; and/or

- the routes with the least paths in common are selected, such that spatial diversity is maximized, and a multi-path data transmission is established.

If the source station 101 is able to determine that a route has not been established, is not able to transmit data to the sink station in accordance with a minimum data rate, or is not able to use the Directional Multi-Gigabits (DMG) transmission mode, the route is excluded from the list of routes to be used.

The transmission budget TXB available for the user of source station 101 is distributed between the routes selected to perform the data transmission. By default, the allocated time duration TD for each route is equal. Alternatively, the allocated time duration TD can be weighted according to the data rate transmission DRT and/or the number of paths of the route. The allocated time duration TD is expressed as a percentage % of the overall time used to transmit data over the shared network.

In step 204, a ratio Tn is determined for each route Rn. The ratio Tn corresponds to the route n’s capacity to transmit the application data stream (a set of data packets), and is given by the following equation:

Tn = (TD * DRT)/ADR [equation 1]

The ratio Tn is thus expressed as a percentage of the application data rate ADR.

If the ratio Tn is equal to 100%, the route capacity is precisely adapted to fully transmit the application data stream. One complete or “full” copy of the application data stream can be transmitted over this route.

If the ratio Tn is less than 100%, the route capacity is undersized (not adapted to fully transmit the application data stream). The bandwidth is not efficiently used and some packets will be lost due to overflow. Only a part of the application data stream (partial copy) can be transmitted over this route.

If the ratio Tn is greater than 100%, the route capacity is oversized (able to fully transmit the application data stream) but a part of the bandwidth is not efficiently used due to the underflow. More than one copy of the application data stream (for example, at least one full copy plus one partial copy of the application data stream) can be transmitted over this route.

The aim is thus to combine the usage of the different routes having underflow or overflow to create more application data copies by creating complementary sets of packet transmission.

As shown in Figure 2B, the source station 101 classes the N different routes Rn according to the ratio Tn in a list L from route 1 (R1) to route N (RN, here N is equal to six routes, thus R6). The list L is a circular buffer and a pointer p1 returns to the first element after passing the last element. The routes 1 to N are classed in decreasing order of ratios Tn, wherein route 1 (R1) is the route with the highest ratio (T1), and route N (RN) is the route with the lowest ratio (TN). The pointer p1 of the list L is initialized to route 1 (p1 = 1). It may be noted that some routes, such as routes R5, R6 have ratios Rn below a minimum threshold, and are thus not included.

In step 205, the sum of the ratios Tn is calculated, and it is determined whether this sum is greater than or equal to 100%. If the response is yes, the source station 101 is able to transmit at least one full copy of application data stream, and the method proceeds to step 206.

If however the response is no, the source station 101 is not able to transmit at least one full copy of the application data stream, and the method proceeds to step 208.

The routes Rn having the lowest data rate applications (DTr) can be excluded from the list L in the next loop in the step 203. In the case where the sum of the ratios Tn is less than 100% in a first pass and the list L includes only one route, an error indication is transmitted to the video application 407 by a link layer controller 406, described in further detail in relation with Figure 4.

In step 206, the source station 101 determines a list of routes for which the sum of the corresponding ratio Tn is greater than or equal to 100%. The list L of routes preferably comprises at least one route not previously used to transmit a copy of application data, which increases robustness to the 60 GHz shadowing issue by providing radio path diversity. In order to perform such a determination, the source station 101 uses a second pointer p2 in order to obtain a sum of the ratios between pointer p1 and pointer p2 greater than 100%.

In step 207, the source station determines how to transmit a copy of application data over the different selected routes. An application data copy is split into a set of unique data packets (indexed from 0 to NB-1, where NB is the number of unique data packets constituting the set). Each unique data packet is built in order to transmit the same quantity of data application. Preferably, the data packets are constituted by a same size of data application payload. Each unique data packet is transmitted over one of the previously selected routes.

By transmitting one data packet over one selected route, the source station will use a same bandwidth ratio. The set of data packets is split into a number of subsets of data packets. The number of subsets of data packets equals the number of selected routes. Each subset of data packets is transmitted over each selected route. The number of data packets constituting a subset of data packets is proportional to the ratio Tn associated with the corresponding route Rn.

The data packets may be randomly put in the different routes. Alternatively, they are put based on the order of payload storage performed by the application. Preferably, the following description of the invention is illustrated by considering a choice based on the order of presentation performed by the application.

In order to perform a full copy data transmission, the source station transmits the previous set of data packets over the different routes allowing the required bandwidth (100%) to be obtained.

The source station 101 defines a set of data packets to be transmitted over the routes indicated by the pointers p1 to pointer p2. The set is defined as a succession of packets, and is typically considered to be a sequence of a number NB of packets with an index modulo 0 to (NB-1). Each route will be used to transmit at least a portion of the set of NB packets proportional to the associated data rate. For example, the number of packets per set is 10 (NB = 10), providing packets with indices 0 to 9.

The number of packets NPn transmitted over a given route Rn is defined as follows:

NPn = Τη I SUM(Tn_p1 to Tn_p2)*NB wherein Tn is the ratio of the given route, SUM is sum of the ratios between the ratio indicated by pointer p1 (Tn_p1) and the ratio indicated by pointer p2 (Tn_p2).

The number of packets NPn is rounded up or down to the next integer value, taking into account that the transmission of NPn packets should not exceed the route capacity.

The first route [R_p1] indicated by the pointer p1 is used to transmit the packets from index IP(0) to IP(NP_p1 - 1), wherein NP_p1 is the number of packets for that route.

The next route R(p1+1) will be used to transmit the packets from index IP(NP_p1) to IP[NP_p1 + (NP_(p1+1) - 1], wherein NP_(p1+1) is the number of packets for that route.

The next route R(p1+2) will be used to transmit the packets from index IP[NP_p1 + NP_(p1+1)] to IP[NP_p1 + NP_(p1+1) + NP_(p1+2) - 1], wherein NP_p1 is the number of packets for that route, and so forth, each time adding the number of packets of the previous route to the first index value and adding the number of packets of the current route to the second index value.

Examples of the above will be provided in further detail in relation with Figures 3. Nevertheless, this is just one method of determining the packets to be transmitted by each route, and other methods may be applied.

Following this multi-path copy data transmission sequence determination, the ratio of the routes used is updated, that is to say, the difference the number of packets a route could transmit and the number of packets actually transmitted. The used ratio is subtracted from the previous ratio Tn used by the multi-path copy data transmission sequence. The first pointer p1 is then set to pointer p2+1.

The method then returns to step 205, and may repeat steps 206, 207 to determine another multi-path copy data transmission sequence determination.

In step 208, the sum of the remaining ratios of the different routes is insufficient to create a new data set enabling a complete copy of the application data stream to be transmitted.

The rest of bandwidth is used to complete, for each route, the sequence(s) already defined in step 207. The selection of packet indices to transmit is done in order to be complementary to the packet indices transmitted on the other routes.

In step 209, the source station 101 and the relay stations (103 to 106) perform the data transmission over the different routes using the multi-path multi-copy data transmission sequences defined previously.

After the transmission, the method 200 returns to step 201.

In step 201, if the input parameters (the path data transmission rate DTr and the transmission budget TXB) are unchanged from the previous execution of step 201, the source station 101 will perform the same multi-path multi-copy data transmission sequence as previously. Otherwise, the method 200 will be repeated as necessary.

Figures 3A, 3B, 3C, 3D are schematic diagrams of a multi-path multi-copy data transmission scheme 300 determined for different routes according embodiments of the invention. More particularly, these figures illustrate evolutions over time of the multi16 path multi-copy data transmission scheme according to packet errors, route disruption, and the discovery of a new route, as considered by the invention.

Figure 3A illustrates a first multi-path multi-copy data transmission scheme 300A determined by the algorithm of Figure 2.

Figure 3B illustrates the first multi-path multi-copy data transmission scheme 300-A while considering packet errors on a route (R1), thus resulting in a data transmission scheme 300-B.

Figure 3C illustrates a second multi-path multi-copy data transmission scheme 300-C in response to the packet errors illustrated by Figure 3B.

Figure 3D illustrates a third multi-path multi-copy data transmission scheme 300D in response to the discovery of a new route (R5) and taking into account the already available routes R2, R3, and R4 illustrated in Figure 3C.

In the figures, the source station 101 transmits data sequences Sd (wherein d is an index from 1 to D, here four sequences S1, S2, S3, S4 are shown) to the sink station 102 over a multi-hop network according to the invention as illustrated in Figure 1 according to the method 200 of Figure 2A. Each data sequence Sd comprises ten data packets PdO to Pd9 (d being the index of the sequence, providing index modulos). It may also be noted that the figures do not depict the transmission over time of the data packets on the routes, but merely the chosen data packets for transmission.

In Figure 3A, a first transmission 300-A occurs of a sequence S1 by means of four routes. The routes with corresponding ratios are selected by means of steps 201 to 204 of the method 200, as follows:

R1 = 80%,

R2 = 60%,

R3 = 40%, and

R4 = 40%.

Routes R1, R2, R3, R4 correspond to routes RT2, RT3, RT4, RT1 respectively.

In step 205, the sum (220%) of the ratios Tn is greater than 100%. Thus, in step 206, routes R1, R2 are selected, providing a sum of 140% (pointer p1 at route R1, pointer p2 at route R2 as shown in Figure 2B). As the sum is greater than 100%, the source station 101 will use routes R1, R2 to transmit partial copies each.

In step 207, a sequence transmission is determined for the source station 101. Route R1 has a number of packets NP1 calculated as follows: NP1 = 80 / (80 + 60)*10, which is equal to 5.7, rounded up to 6. Route R2 has a number of packets NP2 calculated as follows: NP2 = 60 / (80 + 60)*10, which is equal to 4.3, rounded down to 4. Route R1 will transmit, for each sequence, six application packets with index modulos from 0 to 5; that is to say, IP(0) to IP[6_NP1 - 1], thus IP(0) to IP(5). Route R2 will transmit, for each sequence, four application packets with index modulos from 6 to 9; that is to say, IP[6_NP1] to IP[6_NP1 + 4_NP2 - 1], thus IP(6) to IP(9). A preliminary multi-copy data transmission scheme is thus obtained.

Thus, the source station 101 transmits in a first sequence transmission ST1 the following:

- Over route R1 the data packets P10 to P15, and

- Over route R2 the data packets P16 to P19.

Each data packet P10 to P19 is thus a complete copy of an application packet. The ratios are updated as follows: T1 = 80% - 60% = 20 % and T2 = 60% - 40% = 20%. That is to say, route R1 could transmit 8 packets (providing 80%) but only transmitted 6 packets (providing 60%), such that a ratio of 20% (2 packets) is still available for transmission. Likewise, route R2 could transmit 6 packets (providing 60%) but only transmitted 4 packets (providing 40%), such that a ratio of 20% (2 packets) is still available for transmission.

The ratios of the list L are updated as follows:

R1: T1 =20%

R2: T2 = 20%

R3: T3 = 40%

R4: T4 = 40%

Returning to step 205, the sum (120%) of the ratios Tn is still greater than 100%. The source station 101 thus should determine a second copy data transmission, and steps 206 and 207 are performed for a second time. The pointer p1 is then set to p2+1, thus here at route R3, and pointer p2 loops around to point at route R1.

Routes R3, R4, R1 are selected as their sum provides a total at least equal to 100%. Route R3 has a number of packets NP3 = 40 / (20 + 40 + 40)*10 = 4 and will transmit, for each sequence, four application packets with index modulos from 0 to 3; that is to say, IP(0) to IP[4_NP3 - 1], thus IP(0) to IP(3). Route R4 has a number of packets NP4 = 40 / (20 + 40 + 40)*10 = 4 and will transmit, for each sequence, four application packets with index modulos from 4 to 7; that is to say, IP[4_NP3] to IP[4_NP3 + 4_NP4 - 1], thus IP(4) to IP(7). Finally, route R1 has a number of packets

NP1 = 20 / (20 + 40 + 40)*10 = 2 and will transmit, for each sequence, two application packets with index modulos 8 and 9; that is to say, IP[4_NP3 + 4_NP4] to IP[4_NP3 + 4_NP4 + 2_NP1 - 1], thus IP(8) to IP(9). The following sequence transmission will be performed - route R3 will transmit four packets with index modulos from 0 to 3, route R4 will transmit four packets with index modulos from 4 to 7, and route R1 will transmit two packets with index modulo from 8 to 9.

Thus, the source station 101 transmits in a second sequence transmission ST2 the following:

- Over route R3 the data packets P10 to P13,

- Over route R4 the data packets P14 to P17, and

- Over route R1 the data packets P18, P19.

A second multi-copy data transmission scheme is thus obtained that is complementary to the previous one determined by using different routes and transmitting different packet indices.

The ratios are updated as follows: T1 = 20% - 20% = 0%, T3 = 40% - 40% = 0%, T4 = 40% - 40% = 0%, providing the following:

R1: T1 = 0%

R2: T2 = 20%

R3: T3 = 0%

R4: T4 = 0%

Returning to step 205, the sum (20%) of the ratios Tn is now lower than 100%. The remaining ratio Tn of the routes is insufficient to create a new data set enabling a full copy of the application data stream to be transmitted. The source station 101 is thus unable to determine a third copy data transmission, and the method proceeds to step 208.

In step 208, the remaining ratio Tn (20%) is used to complete, for each remaining route, the sequence already defined in the previous iteration of step 207. The choice of packet indexes is done in order to be complementary to the packet indexes on the other routes. For each packet index, the number of copies transmitted over the different routes is determined. For the packet index having the lower number of copies, an additional data packet is selected for transmission and added to the multi-path multicopy data transmission scheme and the remaining ratio Tn is modified. Preferably, the additional data packet transmissions are performed over the routes that have not already transmitted the corresponding indexes.

This process is repeated as long as the remaining ratio Tn allows additional data packets to be transmitted.

According to the implementation shown in Figure 3A, route R2 is already transmitting the packets with indices from 6 to 9, and can further transmit an additional 20% of the application data stream, that is to say two packets (NP2 = 20%*10 = 2 packets). It may be noted that as the sum is no longer greater than or equal to 100%, route R2 will thus also transmit the packets with index modulos 4 and 5 in order to complement the packets transmitted over route R3.

Thus, the source station 101 transmits in a third sequence transmission ST3 over route R2 the data packets P14, P15.

In step 209, the source station 101 transmits the application packets over the different routes R1 to R4 using the above-determined multi-path multi-copy data transmission scheme.

At the end of each data sequence Sd, the source station 101 returns to step 201 and may proceed with a different multi-path multi-copy data transmission scheme according to input parameters including the transmission budget, data rate transmission user over each path or the application data rate.

In summary, the aim is thus to transmit different copies by combining different routes, for example a first combination of routes R1, R2, a second combination of routes R3, R4, R1 taking into consideration the first combination, and so forth. The likelihood of all data packets being delivered in the case of route failure is increased, for example:

- if route R1 fails, its packets (P10 to P15 and P18, P19) are delivered by route R2 (P14, P15, P18, P19) and route R3 (P10 to P13);

- if route R2 fails, its packets (P14 to P19) are delivered by route R1 (P14, P15, P18, P19) and route R4 (P16, P17);

- if route R3 fails, its packets (P10 to P13) are delivered by route R1 (P10 to

R13);

- if route R4 fails, its packets (P14 to P17) are delivered by route R2 (P14 to

P17);

- if routes R1 and R4 fail, their packets (P10 to P19) are delivered by route R2 (P14 to P19) and route R3 (P10 to P13);

- if routes R2 and R3 fail, their packets (P10 to P19) are delivered by route R1 (P10 to P15, P18, P19) and route R4 (P16, P17);

- if routes R3 and R4 fail, their packets (P10 to P17) are delivered by route R1 (P10 to P15) and route R2 (P16, P17);

and so forth.

In Figure 3B, a second transmission 300-B occurs of a sequence S2 by means of four routes since the input parameters have not changed. The same packet attribution is maintained.

However, at some point, route R1 experiences shadowing, such that some data packets (for example packets P23, P24, P25, P28, P29 (represented as crossed out) are lost. Nevertheless, copies of these packets are still transmitted by the other routes.

It is now necessary to modify the transmission scheme as illustrated by Figure 3C.

In Figure 3C, a third transmission 300-C occurs of a sequence S3 by means of three routes since route R1 has been dropped from the list of available routes. The routes R1, R2, R3 with corresponding ratios are selected by means of steps 201 to 204 of the method 200, as follows:

R2 = 80%,

R3 = 50%, and

R4 = 50%.

In the third transmission 300-C, as the route R1 is no longer used to transmit data packets, the time ratio T1 is null, such that the route R1 is no longer selected in step 203.

As the transmission budget TXB is unchanged, the previous time T1 spent to transmit data packets during the transmissions 300-A, 300-B is redistributed over the routes R2, R3, R4 in step 204.

In this example, the number of routes selected in step 202 is four (R1 to R4) for each of the transmissions 300-A, 300-B and is three (R2 to R4) for the transmission 300-C. The time ratios T2, T3, T4 are computed proportionally:

T2 = 60 % x 4/3 = 80%

T3 = 40 % x 4/3 = 50%

T4 = 40 % x 4/3 = 50%

Again, as R1 is not used for the transmission 300-C, the time ratio T1 = 0%.

In step 205, the sum (180%) of the ratios Τη (T2 to T4) is greater than 100%. Thus, in step 206, routes R2, R3 are selected (pointer p1 at route R2, pointer p2 at route R3) since the sum of their ratio equals 130% (which is greater than 100%).

In step 207, a sequence transmission is determined for the source station 101. Route R2 has a number of packets NP2 calculated as follows: NP1 = 80 / (80 + 50)*10, which is equal to 6.1, rounded down to 6. Route R3 has a number of packets NP3 calculated as follows: NP3 = 50 / (80 + 50)*10, which is equal to 3.8, rounded up to 4. Route R2 will transmit, for each sequence, six application packets with index modulos from 0 to 5; that is to say, IP(0) to IP[6_NP2 - 1], thus IP(0) to IP(5). Route R3 will transmit, for each sequence, four application packets with index modulos from 6 to 9; that is to say, IP[6_NP2] to IP[6_NP2 + 4_NP3 - 1], thus IP(6) to IP(9).

Thus, the source station 101 transmits in a fourth sequence transmission ST4 the following:

- Over route R2 the data packets P30 to P35, and

- Over route R3 the data packets P36 to P39.

A first multi-copy data transmission scheme is thus obtained.

The ratios are updated as follows: T2 = 80% - 60% = 20%, T3 = 50% - 40% =

10%.

The ratios of the list L are updated as follows:

R2: T2 = 20%

R3: T3= 10%

R4: T4 = 50%

Returning to step 205, the sum (80%) of the ratios Tn is now lower than 100%. The remaining ratio Tn of the routes is insufficient to create a new data sequence enabling a full copy of the application data stream to be transmitted. The source station 101 is thus unable to determine a second full copy data transmission, and the method proceeds to step 208.

In step 208, the remaining ratio Tn (80%) is used to complete, for each remaining route, the sequence already defined in the previous iteration of step 207. The choice of packet indexes is done in order to be complementary to the packet indexes on the other routes. In particular, the packets sent by routes R3, R4 will be chosen to provide one full sequence.

According to the implementation shown in Figure 3C, route R4 transmits five packets IP(0) to IP(4). Route R2 is already transmitting the packets with indices from 0 to 5, and can further transmit an additional 20% of the application data stream, that is to say two packets, hence those with index modulos IP(6) and IP(7). Route R3 is already transmitting the packets with indices 6 to 9, and can further transmit an additional 10% of the application data stream, that is to say one packet with the index modulo IP(5). The packets sent by routes R3, R4 thus provide one full sequence. All packets, except packets (8) and (9), are sent twice.

Thus, the source station 101 transmits in a fifth sequence transmission ST5 the following:

- Over route R2 the data packets P36 and P37,

- Over route R3 the data packets P35, and

- Over route R4 the data packets P30 to P34.

In step 209, the source station 101 transmits the application packets over the different routes R2 to R4 using the above-determined multi-path multi-copy data transmission scheme.

In Figure 3D, a fourth transmission 300-D occurs of a sequence S4 by means of four routes, wherein a new route R5 has been added to the list, in the place of route R1. The source device has therefore been informed that a new route is available and modifies the scheme in order to utilize the new route R5 (or a new availability of a previous route, such as route R1 becoming available again).

Routes R2, R3, R4, R5 with corresponding ratios are selected by means of steps 201 to 204 of the method 200, as follows:

R2 = 60%,

R3 = 40%,

R4 = 40%, and

R5 = 20%,

In step 205, the sum (160%) of all the ratios Τη (T2 to T5) is greater than 100%. Thus, in step 206, routes R2, R3 are selected (pointer p1 at route R2, pointer p2 at route R3), to obtain a sum equal to 100%.

In step 207, a sequence transmission is determined for the source station 101. Route R2 has a number of packets NP2 calculated as follows: NP1 = 60 / (60 + 40)*10, which is equal to 6. Route R3 has a number of packets NP3 calculated as follows: NP3 = 40 / (60 + 40)*10, which is equal to 4. Route R2 will transmit, for each sequence, six application packets with index modulos from 0 to 5; that is to say, I P(0) to IP[6_NP2 1], thus IP(0) to IP(5). Route R3 will transmit, for each sequence, four application packets with index modulos from 6 to 9; that is to say, IP[6_NP2] to IP[6_NP2 + 4_NP3 - 1], thus IP(6) to IP(9). A preliminary multi-copy data transmission scheme is thus obtained.

Thus, the source station 101 transmits in a sixth sequence transmission ST6 the following:

- Over route R2 the data packets P40 to P45, and

- Over route R3 the data packets P46 to P49.

The ratios are updated as follows: T2 = 60% - 60% = 0%, and T3 = 40% - 40% =

0%

The ratios of the list L are updated as follows:

R2: T2 = 0%

R3: T3 = 0%

R4: T4 = 40%

R5 : T5 = 20%.

Returning to step 205, the sum (60%) of the ratios Τη (T2 to T5) is now lower than 100%. The remaining ratio Tn of the routes is insufficient to create a new data sequence enabling a full copy of the application data stream to be transmitted. The source station 101 is thus unable to determine a second full copy data transmission, and the method proceeds to step 208.

In step 208, the remaining ratio Tn (60%) is used to complete, for each remaining route, the sequence already defined in the previous iteration of step 207. The choice of packet indexes is done in order to be complementary to the packet indexes on the other routes.

According to the implementation shown in Figure 3D, route R4 transmits four packets IP(6) to IP(9), to be complementary to route R3, and route R5 transmits two packets I P(4) and I P(5).

Thus, the source station 101 transmits in a seventh sequence transmission ST7 the following:

- Over route R4 the data packets P46 to P49, and

- Over route R5 the data packets P44 and P45.

In step 209, the source station 101 transmits the application packets over the different routes R2 to R5 using the above-determined multi-path multi-copy data transmission scheme.

Figure 4 schematically illustrates a configuration of a station 400 (or “communication device”) implemented in the system 100, for example the source station 101, the sink station device 102, or an intermediate station 103, 104, 105, 106.

A communication device 400 generally comprises:

- a processor 401 (PROC), such as a micro-controller or a central processing unit CPU;

- at least one Random Access Memory 402 (RAM);

- a Read-Only Memory 403 (ROM);

- a first communication interface 404 (I NT1);

- a second communication interface 405 (INT2);

- a link layer controller 406 (LINK);

- a video application module 407 (VA); and

- a communication bus 408 (CB).

The processor 401, memories 402, 403, first and second communication interfaces 404, 405, the link layer controller 406, and the video application module 407 exchange data and control information via the communication bus 408.

The first communication interface 404 may be a wireless communication interface such as specified by the standard 802.11 ad, enabling communications on a wireless network. In this case, the first communication interface 404 further comprises, in the case of a 60 GHz wireless communication interface, a physical layer module 409 (PHY1) and a medium access controller 410 (MAC1), and is coupled to an interface communication means 411 (CM1), here an antenna.

The physical layer module 409 is configured to process a signal supplied by the medium access controller 410 before it is sent out by the communication means 411, such as by modulation, frequency transposition and power amplification processes. The physical layer module 409 is also configured to process a signal received by the communication means 411 before it is supplied to the medium access controller 410.

The medium access controller 410 is configured to manage accesses to the communication means 411, as well as provide synchronization control, that is to say controls synchronization relative to a beacon interval, scheduling transmissions via the communication means 411. More specifically, the medium access controller 410 is configured to schedule the beginnings and the ends of data emissions and receptions in the network by the communication means 411. The communication means 411 (antenna) is configured to support directional MultiGigabits data transfer by allowing a sector for transmitting and receiving signals to be selected.

The second communication interface 405 may be a wired communication interface such as specified by the Ethernet standard, enabling communications on a wired network, for example. In this case, the second communication interface 405 further comprises a physical layer module 412 (PHY2) and a medium access controller 413 (MAC2), and is coupled to an interface connection means 414 (CM2), for example a physical cable for wired interface.

The physical layer module 412 is configured to process a signal supplied by the medium access controller 413 before it is sent out by the communication means 414, for example ensuring that it conforms to the electrical specifications and access mode of the communication means 414. The physical layer module 412 is also configured to process a signal received by the communication means 414 before it is provided to the medium access controller 413.

The processor 401 is capable of executing instructions from the memory 402 pertaining to a computer program stored in an internal memory, such as the memory 403, or from an external memory (not shown), the computer programs (algorithms) described in further detail in relation to Figure 2A. In particular, the computer program may be a non-transitory computer readable medium storing a program which when executed by a microprocessor of a computer system in a device, such as the source device 101, causes the device to the perform the method 200 described in relation with Figure 2A.

The processor 401 controls the overall operation of the communication device 400, and acts as a data analyser unit to analyze the useful data payload (also referred as MAC payload) of a packet received from another communication device, received via the first or second communication interface.

The communication device 400 may acquire and reproduce an application over a link 415 (LNK) coupled to the video application module 407. The application may be a compressed video stream, file storage, a video camera output, or a display input for example. The video application module 407 is configured to convert application data into data packets able to be transmitted over one of the communication networks, and thus packetizes the application data and transmits it to the link layer controller LINK 406. Conversely, the video application module 407 is also configured to convert packets received from the link layer controller 406 into data applications to be sent to the application over the link 415. One preferred embodiment type of data packet managed by the video application module 407 is TCP/IP or UDP/IP video lossless compressed data with data rate around 100 to 400 Mbps.

The link layer controller 406 is configured to establish the link between the source and sink stations so that the packets may be sent and received between the video application module 407 and the communication interfaces 404 and/or 405. For a source station 101, the link layer controller 406 generates and transmits data packets as described in further detail in relation with the preceding figures. For an intermediate station 103 to 106, the link layer controller 406 decodes multi-copy data packets received from the first communication network 404 (60 GHz) and will either generate and analyze control packets or else forward data packets to the sink station 102. For a sink station 102, the link layer controller 406 will implement methods (algorithms) for data packet reception and control the transmission and reception of data packets.

Consequently, the communication device 400 may be a wireless and a wired device, comprising both the wireless communication interface and the wired communication interface. Alternatively, the communication device 400 may be a wired device or a wireless device, in which case the wireless communication interface or the wired communication interface are not present respectively.

For example, a source station 101 that is a portable device (such as a cellular phone) may only comprise the wireless communication interface, a sink station 102 that is a fixed device (for example a server) may only comprise the wired communication interface, and the intermediate stations 103 to 106 may comprise both the wireless and the wired communication interfaces, in order to communicate with both the source station 101 and the sink station 102. Furthermore, in the case of the intermediate stations 103 to 106, the video application module 407 may not be present, as there is no need to perform video applications.

The interfaces 404, 405, as well as the video application module 407 and their connections are thus shown in dotted lines as they are optional features.

An aspect of the invention relates to a communication system comprising at least one source device according to an embodiment of the invention and at least one sink device, the source device being configured to determine a transmission scheme of at least one full copy of a set of data packets to be transmitted to the sink device by means of at least two routes of the communication system, each route comprising at least one wireless path.

Another aspect of the invention relates to a non-transitory computer readable medium storing a program which when executed by a microprocessor or computer system in a device causes the device to perform the method according to one embodiment of the invention.

Another aspect of the invention relates to a method of determining a 10 transmission scheme substantially as hereinbefore described with reference to, and as shown in Figure 2A.

Although the present invention has been described hereinabove with reference to specific embodiments, the present invention is not limited to the specific embodiments, and modifications which lie within the scope of the present invention will be apparent to a person skilled in the art. In particular different features from different embodiments may be interchanged, where appropriate. Many further modifications and variations will suggest themselves to those versed in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only and which are not intended to limit the scope of the invention as determined by the appended claims.

Claims

1. A method of determining a transmission scheme of at least one full copy of a set of data packets to be transmitted from a source device to a sink device by means of at least two routes of a communication system, each route comprising at least one wireless path, the method comprising the steps of:

2. The method according to claim 1, further comprising a step of obtaining input parameters comprising:

3. The method according to claim 2, further comprising a step of estimating a data rate transmission to be used by each route, the data rate transmission depending on the physical data rates of the one or more wireless paths composing the route.

4. The method according to one of claims 1 to 3, further comprising a step of selecting routes among the routes of the communication system for a multi-path multicopy data transmission.

5. The method according to claim 4, wherein the selection of the routes depends on at least one of the following selection criteria:

the routes having the highest number of wired paths;

the routes having the highest data rate transmissions;

the routes that have already performed data set transmissions;

the routes comprising a minimum number of wireless paths; and/or the routes with the least paths in common.

6. The method according to one of claims 4 or 5, further comprising a step of determining, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate.

7. The method according to one of claims 4 to 6, wherein the distributing step further comprises the steps of:

8. The method according to claim 7, further comprising a step of determining, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate; and wherein the number of packets to be transmitted over a route is proportional to the ratio associated with the route.

9. The method according to one of claims 1 to 8, wherein the distributing step comprises transmitting data packets of the set over a route of the communication system, and transmitting other data packets of the set over another route.

10. The method according to one of claims 6 to 9, wherein in response to the transmission of at least one full copy, the method further comprises:

updating, for each selected route, its ratio;

11. A source device in a communication system further comprising at least one sink device, the source device being configured to determine a transmission scheme of at least one full copy of a set of data packets to be transmitted to the sink device by means of at least two routes of the communication system, each route comprising at least one wireless path, the source device being configured to:

12. The device according to claim 11, wherein the device is further configured to obtain input parameters comprising:

13. The device according to claim 12, wherein the device is further configured to estimate a data rate transmission to be used by each route, the data rate transmission depending on the physical data rates of the one or more wireless paths composing the route.

14. The device according to one of claims 11 to 13, wherein the device is further configured to select routes among the routes of the communication system for a multi-path multi-copy data transmission.

15. The device according to claim 14, wherein the device is further configured to select the routes depending on at least one of the following selection criteria:

the routes having the highest number of wired paths;

the routes having the highest data rate transmissions;

the routes that have already performed data set transmissions;

16. The device according to one of claims 14 or 15, wherein the device is further configured to determine, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate.

17. The device according to one of claims 14 to 16, wherein the device is further configured to:

determine a number of packets to be transmitted over each selected route; determine which packets of the set of data packets will be transmitted by each selected route; and establish a transmission sequence of the data packets.

18. The device according to claim 17, wherein the device is further configured to determine, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate; and wherein the number of packets to be transmitted over a route is proportional to the ratio associated with the route.

19. The device according to one of claims 11 to 18, wherein the device is further configured to perform the distribution by transmitting data packets of the set over a route of the communication system, and transmitting other data packets of the set over another route.

20. The device according to one of claims 16 to 19, wherein in response to the transmission of at least one full copy, the device is further configured to:

update, for each selected route, its ratio;

Amendments to the claims have been made as follows:

01 09 17

1. A method of determining a transmission scheme of at least one full copy of a set of data packets to be transmitted from a source device to a sink device by means

5 of at least two routes of a communication system, each route comprising at least one wireless path, the method comprising the steps of:

determining, based on the capacities of the routes, whether at least one 10 complete copy can be transmitted; and if the response is yes, then distributing at least two subsets of data packets amongst the routes based on the determined capacities of the routes for complementary transmission of at least one complete copy of the set of data packets.

15 2. The method according to claim 1, further comprising a step of obtaining input parameters comprising:

transmission budgets available for all the routes, a transmission budget relating to a percentage of the overall time available to transmit data over the network; and

20 an application data rate relating to a data rate required to transmit the data packets over the physical layer.

3. The method according to claim 2, further comprising a step of estimating a data rate transmission to be used by each route, the data rate transmission depending

25 on the physical data rates of the one or more wireless paths composing the route.

the routes having the highest number of wired paths; the routes having the highest data rate transmissions;

35 the routes that have already performed data set transmissions;

01 09 17 the routes comprising a minimum number of wireless paths; and/or the routes with the least paths in common.

6. The method according to one of claims 4 or 5, further comprising a step of 5 determining, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate.

7. The method according to one of claims 4 to 6, wherein the distributing step

10 further comprises the steps of:

8. The method according to claim 7, further comprising a step of determining, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate; and wherein the number of packets to be transmitted over a route is proportional to 20 the ratio associated with the route.

9. A method of transmitting at least one full copy of a set of data packets from a source device to a sink device by means of at least two routes of a communication system, each route comprising at least one wireless path, according to a transmission

25 scheme determined by the method according to one of claims 1 to 8, further comprising the steps of:

transmitting a subset of data packets of the at least two subsets over a route of the communication system, and transmitting at least another subset of data packets of the at least two subsets 30 over another route.

10. The method according to claim 9, wherein in response to the transmission of at least one full copy, the method further comprises:

updating, for each selected route, its ratio;

01 09 17 determining that only a partial copy of the set of data packets can be transmitted;

5 selecting for transmission a packet with a lower number of copies; and transmitting the selected packet over a selected route.

11. A source device in a communication system, the communication system further comprising at least one sink device, the source device being configured to

10 determine a transmission scheme of at least one full copy of a set of data packets to be transmitted to the sink device by means of at least two routes of the communication system, each route comprising at least one wireless path, the source device being configured to:

determine for each route, based on transmission conditions of its wireless

15 paths, its capacity to transmit at least one complete copy of the set of data packets;

determine, based on the capacities of the routes, whether at least one complete copy can be transmitted; and if the response is yes, then distribute at least two subsets of data packets amongst the routes based on the determined capacities of the routes for

20 complementary transmission of at least one complete copy of the set of data packets.

transmission budgets available for all the routes, a transmission budget

25 relating to a percentage of the overall time available to transmit data over the communication system; and an application data rate relating to a data rate required to transmit the data packets over the physical layer.

30 13. The device according to claim 12, wherein the device is further configured to estimate a data rate transmission to be used by each route, the data rate transmission depending on the physical data rates of the one or more wireless paths composing the route.

01 09 17

5 15. The device according to claim 14, wherein the device is further configured to select the routes depending on at least one of the following selection criteria:

the routes having the highest number of wired paths;

the routes having the highest data rate transmissions;

the routes that have already performed data set transmissions;

10 the routes comprising a minimum number of wireless paths; and/or the routes with the least paths in common.

16. The device according to one of claims 14 or 15, wherein the device is further configured to determine, for each selected route, a ratio corresponding to the

15 capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate.

20. The device according to claim 19, wherein in response to the transmission of at least one full copy, the device is further configured to:

10 update, for each selected route, its ratio;

15 select for transmission a packet with a lower number of copies; and transmit the selected packet over a selected route.

Intellectual

Property

Office

Application No: Claims searched:

GB 1618227.1 1-20

20 determine a number of packets to be transmitted over each selected route;

determine which packets of the set of data packets will be transmitted by each selected route; and establish a transmission sequence of the data packets.

25 18. The device according to claim 17, wherein the device is further configured to determine, for each selected route, a ratio corresponding to the capacity of a route to transmit the set of data packets, expressed as a percentage of the application data rate; and wherein the number of packets to be transmitted over a route is proportional to

30 the ratio associated with the route.

19. A source device in a communication system, the communication system further comprising at least one sink device, the source device being configured to determine a transmission scheme of at least one full copy of a set of data packets to be

35 transmitted to the sink device by means of at least two routes of the communication

01 09 17 system according to one of claims 11 to 18, each route comprising at least one wireless path, the source device being further configured to:

transmit a subset of data packets of the at least two subsets over a route of the communication system, and

5 transmit at least another subset of data packets of the at least two subsets over another route.