Data transmission methods, communication devices and associated systems.

Abstract

A method for transmitting data between a data server device (1000) and a data receiver client device (1100) in a communication network is described, the server device comprising a memory (1002) containing software code (1008) and a processor (1001) which, when it executes the software code, causes the server device to implement the method, the method comprising: obtaining (201), over a first period of time, a plurality of measurements characterizing a transmission quality between the client device and the server device; determining (202), based on the measurements, information characterizing, as a function of time, a relative transmission quality level during the first period; transmitting (203) the information to the client device.Also described are a transmission method implemented by a client device, a client device, a server device, and a system comprising a client device and at least one server device. Figure for the abstract: 3.

Description

Title of the invention: Data transmission methods, communication devices and associated system. Technical field

[0001] Methods for transmitting data, communication devices for respectively transmitting and receiving the data, an associated system and computer program product are described. The solutions described apply, in a non-limiting manner, in the context of a transmission of data collected recurrently. Technical background

[0002] In many applications, devices accumulate data periodically or non-periodically requiring collection, by a receiving client device, of the data accumulated by a producing server device. This is for example the case of meters of various types, such as electricity, gas, water or even thermal energy meters. Such a device can generate periodic data, for example a value measured repeatedly by the meter over a given period, or in the event of the occurrence of various events. The data is accumulated while awaiting transmission to the collecting client device.

[0003] Communication between the server and the client may take place over a network whose transmission conditions may vary. These devices may, for example, be equipped with a 2G to 5G cellular network interface, which is subject to interference and whose load may vary. In addition, the network may be more or less saturated. Carrying out a transmission under unfavorable conditions has harmful consequences: the frames sent may not be received correctly and it may be necessary to make one or more additional attempts to resend certain frames. This contributes not only to possible network saturation, but also to overconsumption of data by the server device.

[0004] There is a need for an efficient transmission method taking these aspects into account. Summary

[0005] One or more embodiments relate to a method of transmitting data between a data server device and a client device receiving the data in a communication network, the server device comprising a memory comprising software code and a processor which, when it executes the software code, causes the server device to implement the method, the method comprising: - obtaining, over a first period of time, a plurality of measurements characterizing a quality of transmission between the client device and the server device; - the determination, based on the measurements, of information characterizing, as a function of time, a relative level of transmission quality during the first period; - transmission of information to the client device.

[0006] The server device thus collects information characterizing, as a function of time, a relative quality level of transmission during a first period, which will allow the client device to implement this information to decide on a suitable time to request the transmission of data during a future period. In addition, the information characterizes a relative quality level of transmission during the first period, which makes it possible to characterize the best quality level to which the server device can aspire.

[0007] According to one or more embodiments, the first period being subdivided into time intervals, the determination of the information comprises the determination of a quality level for each interval on the basis of the measurements carried out for this interval with respect to one or more thresholds determined from the measurements carried out over the entire first period.

[0008] According to one or more embodiments, the threshold(s) are chosen between the highest and the lowest measurement value of the first period.

[0009] According to one or more embodiments, the determination of the information and the transmission of this information are carried out periodically.

[0010] According to one or more embodiments, the first period is one of: a time slot of a day, a day.

[0011] According to one or more embodiments, the method comprises receiving a request to transmit data from the client device and transmitting data in response to the request.

[0012] One or more embodiments relate to a method of transmitting data between at least one data server device and a data receiver device in a communications network, the receiver device comprising a memory comprising software code and a processor which, when it executes the software code, causes the receiver device to implement the method, the method comprising: - the reception, from a given server device, of information characterizing an evolution of a relative level of transmission quality between the client device and said given server device during a first period of time; - the estimation of the relative transmission quality level during a given time interval of the second period on the basis of said information corresponding to the same time interval of the first period, the time slot covered by the first period including at least the time slot of the second period; - the decision to send a request for data transmission to the given server device during the given interval based on the comparison of the estimate for this interval with a quality threshold.

[0013] According to one or more embodiments, the decision to send is made as time progresses during the second period, until a send results in the successful receipt of said data.

[0014] According to one or more embodiments, said quality threshold is a function of the placement of the given interval in the second period, the quality threshold having a maximum value at the start of the second period and decreasing as time progresses in the second period towards a minimum value.

[0015] According to one or more embodiments, the second period is one of - a part of a day corresponding to the same part of the day covered by the first day on a previous day; - the day following a day covered by the second period.

[0016] According to one or more embodiments, the method comprises receiving information from a plurality of server devices, the decision to send a request to a server device being based on the information received from this server device.

[0017] One or more embodiments relate to a server device comprising a memory comprising software code and a processor which, when executing the software code, causes the server device to implement one of the described methods.

[0018] One or more embodiments relate to a client device comprising a memory comprising software code and a processor which, when executing the software code, causes the client device to implement one of the described methods.

[0019] One or more embodiments relate to a system comprising a client device and at least one server device.

[0020] One or more embodiments relate to a non-transitory recording medium readable by a device having a processor, said medium comprising instructions which, when the program is executed by a processor of a device, cause the device to implement at least one of the methods described. Brief description of the figures

[0021] Other features and advantages will become apparent as you read the description. detailed description which follows for the understanding of which one will refer to the attached drawings among which:

[0022] [Fig.l] - [Fig.l] is a block diagram of a system comprising a server device and a client device according to one or more embodiments;

[0023] [Fig.2] - [Fig.2] is a flowchart of a method implemented by a data server device according to one or more exemplary embodiments;

[0024] [Fig.3] - [Fig.3] is a flowchart of a method corresponding to a step of the method of [Fig.2] according to one or more exemplary embodiments;

[0025] [Fig.4] - [Fig.4] is a flowchart of a method implemented by a data receiving device, or client device, according to one or more exemplary embodiments. Detailed description

[0026] In the following description, identical, similar or analogous elements will be designated by the same reference numbers.

[0027] The block diagrams, flowcharts and message sequence diagrams in the figures illustrate the architecture, functionalities and operation of systems, devices, methods and computer program products according to one or more exemplary embodiments. Each block of a block diagram or each phase of a flowchart may represent a module or a portion of software code comprising instructions for implementing one or more functions. According to certain implementations, the order of the blocks or phases may be changed, or the corresponding functions may be implemented in parallel. The process blocks or phases may be implemented using circuits, software or a combination of circuits and software, in a centralized manner, or in a distributed manner, for all or part of the blocks or phases.The systems, devices, methods and methods described may be modified, added to and / or deleted within the scope of this disclosure. For example, the components of a device or system may be integrated or separated. Also, the described functions may be implemented using more or fewer components or phases, or with other components or through other phases. Any suitable data processing system may be used for the implementation. A suitable data processing system or device may, for example, include a combination of software code and circuitry, such as a processor, controller or other circuitry suitable for executing the software code. When the software code is executed, the processor or controller causes the system or device to implement some or all of the functionalities of the blocks and / or phases of the methods or methods according to the exemplary embodiments.The software code can be . stored in a memory or readable medium accessible directly or through another module by the processor or controller.

[0028] [Fig. 1] is a block diagram of a communication network comprising a device 1000 and a device 1100 capable of communicating through the network in a bidirectional manner, according to a non-limiting exemplary embodiment. The device 1000 is a device which stores accumulated data or accumulates data itself, data of which at least some are to be transmitted to the device 1100. The device 1000 will hereinafter be called 'server' and the device 1100 will be called 'client'. The server device 1000 comprises a processor 1001, a memory 1002, a data source 1003, a user interface 1005, a communication interface 1006 configured to communicate bidirectionally with the client device 1100, a display 1007 adapted for displaying data to a user of the server device 1000, as well as a working memory 1009. The various components of the server device 1000 are connected through a communication bus 1004.The memory 1002 comprises software code 1008. The memory 1009 is used to store and manage the data to be transmitted. When the processor executes the software code 1008, it causes the server device to implement a method according to one or more described embodiments. This data comes for example from the data source 1003. Similarly, the client device comprises a processor 1101, a memory 1102, a mass storage 1103 intended to store the data received from the server or from several servers, a user interface 1105, a communication interface 1106 configured to communicate bidirectionally with the server device 1000, a display 1107, a working memory 1109 and a communication bus 1104. The memory 1102 comprises software code 1108.When the processor executes the software code 1108, it causes the client device to implement a method according to one or more described exemplary embodiments.

[0029] The devices 1000 and 1100 are described above for illustrative purposes and may comprise more or fewer functional blocks than those described above, depending on the requirements of a particular context. In particular, the display may be absent.

[0030] According to one or more exemplary embodiments, the server device 1000 is a metrological meter of a physical quantity (typically a measurement of electricity, water, gas, thermal energy, etc.) while the client device 1100 is a device collecting data from different servers on behalf of the distribution network operator. The data source 1003 is, for example, the metrological unit itself of the meter, a unit which produces a value of the quantity being counted. The metrological unit is, for example, responsible for measuring and recording an absolute physical quantity (intensity of a current, pressure of a gas) or cumulative physical quantity (electrical energy or volume of a gas which has passed through). The data may be obtained periodically or aperiodically or comprise a combination of data obtained periodically and aperiodically. The communication network is for example a radio medium of one of the types 2G / 3G / 4G / LTE NB-loT / LTE Cat-Ml / LoRa or other.

[0031] The DLMS or 'Device Language Message Specification' comprises a series of standards developed and maintained by the DLMS Users Association ('DLMS UA') and standardizing the exchange of data from electric meters or others. The DLMS UA maintains in particular the COSEM 'Blue Book' (for Comprehensive Semantic Model for Energy Management). You can refer to the document 'DLMS UA 1000-1', version 15, part 2, version 1.0 of December 21, 2021 for more information concerning the DLMS.

[0032] The server 1000 and the client 1100 of [Fig. 1] may, by way of non-limiting example, be compatible with the DLMS standard, but the reference to this standard is made essentially to illustrate more clearly a concrete example of embodiment, without this limiting the generality of the disclosure. A person skilled in the art will be able to adapt the teachings of the present description to contexts other than the DLMS.

[0033] According to one or more embodiments, a transmission of data from a server device to the client device is carried out at the initiative of the client device. The client device transmits a request to a server, the latter then initiating the transmission of its data to the client device. The client and the server then operate in request transmission mode, called 'pull' mode in English.

[0034] According to one or more embodiments, a server device determines information characterizing the evolution of a relative quality level of the transmission conditions between the client device and the server device over time, over a given reference time period. This information is a function of quality measurements carried out during this period by the server device, and is communicated by the server device to the client device. The latter can then use the information to select the time(s) to request a transmission, by the server device, of useful data during a future time period.

[0035] The period of time during which the client device will use the information is a period for which it is expected that the evolution of the quality level will be substantially identical or at least close to that of the reference period. The determination of the information characterizing the evolution of a quality level of the transmission conditions over time is carried out and obtained on the basis of real measurements to obtain a relative quality level. Indeed, we take into account, for a given server device, values ​​that the measurements actually achieve and not theoretical values ​​that may not be achieved in practice. The same quality level determined by two separate server devices may therefore indicate different transmission conditions, but for example the best quality level will indicate the best transmission conditions that can be expected for both servers.

[0036] According to one or more exemplary embodiments, the reference period and the future period are periods at the same times of two separate days, for example a period from 6 a.m. to noon. A period may also cover a full day.

[0037] The assumption is made that the behavior of the network presents, for example over substantially identical time slots, analogies in the evolution of the quality level over time. Thus, the information provided by the server device to the client device is a prediction - or even a presumed estimate - of the quality at different times of a similar future period, a prediction which the client device uses to choose the appropriate time to request a transmission from a server to improve the chances of correct reception of the data.

[0038] According to one or more embodiments, the reference period is defined by the client device. For example, the client device may determine the start time and duration of a reference period and transmit it to one or more client devices. According to other embodiments, the reference period is fixed.

[0039] According to one or more embodiments, the time period during which the client device will seek to collect data from the server device corresponds to only a portion of the reference period. Indeed, the server device can transmit information for a reference period longer than the transmission period envisaged by the client device.

[0040] According to one or more exemplary embodiments, the client device can receive information characterizing the evolution of a quality level over time from several server devices and thus request the transmission of data in a differentiated manner for each server device. Indeed, the specific location of a server device can impact the transmission conditions and the evolution of the network conditions can be specific to each server device. The information determined by each server device can therefore differ.

[0041] According to one or more exemplary embodiments, the server device determines information characterizing a quality level as a function of time on the basis of measurements collected over a single reference period or, according to a variant, on the basis of measurements collected over several reference periods. Thus, it is possible to limit the impact of noisy measurements.

[0042] According to one or more exemplary embodiments, the determination of the information characterizing a quality level as a function of time includes the analysis of the collected measurements to determine one or more thresholds in the range of values ​​of the collected measurements, for example over a reference period. The determination of the information is then made as a function of these thresholds.

[0043] According to one or more exemplary embodiments, the period is a day or part of a day. According to a variant, it is distinguished among the days of the week. For example, information characterizing the quality level is determined separately for a day of the week and for a weekend day. Other distinctions can be made according to local customs (working day or not, Sunday, public holiday, etc.). According to other embodiments, the reference period is taken during a weekday identical to that of the transmission period by the client device.

[0044] According to one or more exemplary embodiments, the information characterizing the quality level over time is evaluated by the server device over a reference period and used by the client device for the following similar period. For example, the reference period is a day (respectively a time slot of the day) and the period during which the client device uses the information of this reference period during the following day (respectively during the same time slot of the following day). According to other exemplary embodiments, information determined on the basis of a reference period is used during several similar periods.

[0045] According to one or more exemplary embodiments, the information characterizing the quality level is determined on the basis of a plurality of measurements carried out during the reference period, these measurements characterizing the quality of the transmission (for example, the signal power, the signal / noise ratio, etc.). For a 2G cellular network, they may be based, for example, on the received power indicator ('Received Signal Strength Indicator' or 'RSSI' in English). For a 4G, LTE NB-IoT or LTE Cat-M1 network, the power of a received reference signal ('Reference Signal Received Power' or 'RSRP' in English) may be used, or the quality of the received reference signal ('Reference Signal Received Quality' or 'RSRQ' in English), representative of the signal / noise ratio.

[0046] [Fig. 2] is a flowchart of a method implemented by a server device, according to one or more non-limiting embodiments. The method comprises: - 201 - Obtaining at least one measurement characterizing the quality of transmission between the client device and the server device for each interval of a time period PI subdivided into a plurality of intervals Ix, where x is an integer greater than or equal to 2. - 202 - Determination, for each interval, of a quality level of the transmission conditions between the client device and the server device, based on at least one measurement made for this interval in relation to at least one quality threshold determined from the measurements made over the entire reference period. - 203 - Transmission to the client device of quality levels for all in intervals.

[0047] Determining a quality level from several measurements makes it possible to maintain the information transmitted to the client device in a contained volume of data. Depending on the method of determining the quality level based on the measurements, this also makes it possible to reduce any noise in these measurements (the quality level being able to aggregate, in one way or another, all of the measurements associated with an interval), or to obtain a statistical representation thereof, for example based on percentiles.

[0048] The quality threshold(s) can be defined in various ways. Two examples will now be described.

[0049] According to a first embodiment, the determination of the quality level from the measurements is done in relation to one or more thresholds pre-programmed in the server device.

[0050] According to a non-limiting example, two thresholds are implemented, a first threshold, called high threshold (Threshold_H) and a second threshold, called low threshold (Threshold_B). Above the high threshold, the quality is judged to be good, below the low threshold, the quality is judged to be poor and between the two thresholds, the quality is judged to be average. The pre-programmed thresholds may for example have been determined according to the cases on the basis of typical values ​​for the network considered.

[0051] According to a second embodiment, the determination of the quality level from the measurements is done by learning. One or more thresholds are obtained from the measurements carried out for the entire reference period. This makes it possible, in particular, as indicated previously, to establish the quality threshold(s) in relation to values ​​actually reached by the measurements.

[0052] According to a non-limiting example illustrated by the algorithm of [Fig.3], the server device carries out a multitude of measurements over the entire reference period in 301. Determination of one or more quality thresholds S_i with i being an integer greater than or equal to 1, the thresholds being placed between the highest value and the lowest value measured over the reference period.

[0053] For example, if the reference period is one day and we consider that the quality is measured using the RSRQ, a measurement can be carried out every minute, which which will give 1440 RSRQ measurements. It is assumed in the following that a first measurement value higher than a second measurement value will indicate a quality better than the quality indicated by the second measurement value. The person skilled in the art will know how to adapt the described method if a first value lower than a second value is indicative of a quality better than that corresponding to the second value.

[0054] Once the measurements have been carried out for the reference period, one or more thresholds S_i, with i an integer greater than or equal to 1. A threshold is placed so that Qi% of the best measurements in terms of indicated quality are above this threshold, with i an integer greater than or equal to 1 and with Qi an increasing function of i. This amounts to processing the measurements by percentiles.

[0055] As a numerical example, it was found that a value of i equal to 2 made it possible to obtain good results in an experimental context. As above, these thresholds will be designated by high threshold (S_H) and low threshold (S_B) and above the high threshold, the quality is judged to be good, below the low threshold, the quality will be judged to be poor and between the two thresholds, the quality will be judged to be average. For example, the high threshold could be defined as being a threshold above which the 25% of the best values ​​among the measurements carried out are found, while the low threshold could be defined as being the threshold above which 75% of the best values ​​are placed. Of course, the percentages above are given for illustrative purposes and may have different values.

[0056] According to a variant of the second embodiment, the threshold(s) are determined from measurements carried out over several periods and not just one.

[0057] According to one or more exemplary embodiments, the first embodiment of the determination of the thresholds with preprogrammed value is used while waiting for learning according to the second embodiment to be able to be carried out.

[0058] Once the threshold(s) have been obtained, for each interval of the reference period, a quality level is determined (303) based on the threshold(s) and the measurements corresponding to the interval considered.

[0059] According to a non-limiting example, N quality levels are determined, from the worst quality to the best quality, with N being an integer greater than 2. A quality level is assigned based on the distribution of the measurement values ​​relative to the thresholds.

[0060] For example, we consider two thresholds (high threshold S_H, low threshold S_B), five quality levels (with for example level +2 representing very good quality and level -2 representing very poor quality), a reference period of one day divided into 96 fifteen-minute intervals, with a quality measurement obtained every minute. An example of assigning one of the five quality levels Ki for a given interval is as follows: - We consider the sixteen measures of an interval Ki 1. If 75% (or more) of the measurements are greater than or equal to the upper threshold, then we award level +2 2. Otherwise, if 50% of the measurements are greater than or equal to the upper threshold, then level +1 is assigned. 3. Otherwise, if 75% of the measurements are below the low threshold, then level -2 is assigned. 4. Otherwise, if 50% of the measurements are below the low threshold, then level -1 is assigned. 5. Otherwise, level 0 is assigned.

[0061] The above values ​​are integers centered around zero for illustrative purposes; other scales can of course be used.

[0062] Table 1 is an example of the structure of the useful data included in a frame used for the transmission, by the server device to the client device, of information characterizing the evolution of a quality level of the transmission conditions over time in the form of quality levels per time interval, the table containing a quality level (coded, according to the example, on three bits) per interval of the reference period (i.e., according to the example, 96 intervals). The useful data may have a simpler structure, which for example simply comprises a list of three-bit values ​​in the chronological order of the intervals in the reference period, the interval concerned by a value being implicitly identified by the order of the values.

[0063] [Tables 1] Interval Ki 1 2 n 95 96 Quality level 3 bits 3 bits 3 bits 3 bits 3 bits 3 bits

[0064] According to one or more exemplary embodiments, the transmission, from the server device to the client device, of the information characterizing the evolution of a quality level of the transmission conditions over time is carried out at the end of the reference period or just before or even at the very beginning of the period during which the client device must use it.

[0065] According to one or more exemplary embodiments, the client device implements the information characterizing the evolution of a quality level of the transmission conditions during a reference period received from a given server to determine, during a similar period, the appropriate moments to initiate a data transfer from this server.

[0066] According to one or more exemplary embodiments, if the client device does not receive the information characterizing the evolution of a level of quality of the conditions of transmission over time from a given server device, the client device uses information previously received from that server device.

[0067] The period during which the transmission of data by the server device is subdivided into several sub-periods each covering several contiguous intervals. Taking the sub-periods in chronological order, the client device will search, in a sub-period, whether this period includes one or more intervals having at least one given quality (for example a quality level among N, to take a non-limiting example already described), by lowering the required quality level as the sub-periods progress. If at least one time interval meeting this criterion is found, the client device will transmit to the server device, at the start of each of the intervals found, a message to request the transmission of useful data, until the transmission of the data requested from the server device has been correctly carried out.If no interval matching the quality criterion is found in a sub-period, then no request for transmission of the useful data is transmitted to the server device. If several intervals match, a request is transmitted interval by interval matching the criterion, until the useful data has been correctly received. At the end of a sub-period, we move on to the next sub-period, with a lowering of the required quality level.

[0068] When the end of the period is reached without a correct transmission of the useful data having been able to take place, the method ends. According to a variant, a new test is carried out during another period.

[0069] The progressive lowering of the required quality level initially makes it possible, at the beginning of the period, to search for the intervals giving the best chances of resulting in a successful transmission of the data. The cost in terms of quantity of data transmitted is thus reduced. In the event of failure, as the period progresses, the requirement is lowered. Poorer transmission conditions are then accepted, which may require several transmission attempts for the data to be correctly received. This makes it possible, if necessary, to receive the data, but at a higher cost in terms of quantity of data transmitted.

[0070] According to one or more exemplary embodiments, the number of sub-periods is at least equal to N, where N represents the number of quality levels.

[0071] Table 2 represents an example of the minimum requirement according to the sub-periods. I represents the maximum quality level and 1-6 the minimum quality level. For example, for sub-period 3, the quality criterion required for the interval is that the quality level must be equal to 1, 1-1 or 1-2 for the client device to issue a request for transmission of the useful data during this in- interval.

[0072] In the table, I is an integer in this example, but of course the information characterizing the quality can be coded differently. In addition, the lowering illustrated by Table 1 of a sub-period is one level, but it is possible to lower by several levels and to lower by a different number of levels from one sub-period to another.

[0073] [Tables2] Sub-period 1 2 3 4 5 6 7 Minimum quality level for an interval required to initiate a transmission during this interval I 1-1 1-2 1-3 1-4 1-5 1-6

[0074] Depending on the embodiments, the sub-periods may have substantially equal or very different durations.

[0075] For example, if the period is six hours long, then it can be divided into two two-hour sub-periods, followed by one one-hour sub-period; followed by one 30-minute sub-period and two 15-minute sub-periods. Or, if the period is 8 hours long, then it can be divided into two three-hour sub-periods, followed by one one-hour sub-period, followed by two 30-minute sub-periods.

[0076] According to one or more embodiments, when the minimum level of quality indicated by the information is reached for a given sub-period, it is this same minimum level which is applied for one or more possible following sub-periods, if such sub-periods exist.

[0077] For example; if we take the previous example of distribution into sub-periods, consider five distinct quality levels, consider the highest quality level for the first sub-period, then at least the following quality level for the following sub-period, etc., then the lowest quality level will be required from the first 15-minute sub-period.

[0078] According to certain embodiments, a period can be divided into intermediate periods, each of which is itself divided into sub-periods. The method described above is then applied to each of the intermediate periods, until the collection of data by the client device from the server device in question has been correctly carried out. This makes it possible to repeat the entire method several times per period, starting again for each sub-period from the initial quality requirement. The information characterizing the evolution of the quality level of the transmission conditions over time will have been previously received for the entire period.

[0079] For example, a day is divided into four intermediate periods of six hours, each intermediate period being divided into sub-periods according to the example given previously.

[0080] [Fig.4] is a flowchart illustrating a method implemented by a client device according to one or more exemplary embodiments. The method of [Fig.4] applies for a given server device, but can be used in parallel for several servers.

[0081] Firstly, the client device obtains information characterizing the evolution of the quality level of the transmission conditions during a reference period for a given server device (401).

[0082] The client device will proceed by sub-periods of the period during which it seeks to obtain the transmission of useful data from the server device. For each sub-period, starting with the first (402) and with a maximum required quality level (403), the client device will determine whether a current time interval corresponds to the required quality criterion, namely whether the quality level predicted for this interval in the received information is at least equal to a minimum level depending on the sub-period. This verification is carried out in 404. If the verification is positive, then a request for the transmission of useful data is sent to the server device (408). If the data is correctly received (verification in 409), then the process ends. If the data is not correctly received, then the next interval meeting the quality criterion is awaited (407).

[0083] It is also tested whether the current time interval belongs to the sub-period currently considered (403). If this is not the case and the entire period envisaged for the transmission has not elapsed (verification in 405), then the next sub-period is approached and the required quality level is lowered if it is not at the minimum level (in 406). If the current interval belongs to the current sub-period, step 404 is approached as described in the previous paragraph.

[0084] According to the example of [Fig.4], the determination of whether a time interval meets the quality criterion is performed in real time. However, according to other embodiments, the determination of the intervals corresponding to the criteria is performed in advance and the result of this determination is applied when these intervals occur.

[0085] According to one or more exemplary embodiments, if at the end of the period, no transmission could be requested or if no data transmission could be carried out correctly, a new attempt is made during a subsequent period.

[0086] According to one or more exemplary embodiments, the client device interacts with several server devices. It is then possible to implement the method in parallel for as many server devices as needed, with information on quality evolution specific to each server device.

[0087] According to one or more exemplary embodiments, the duration of a sub-period is dynamically adapted by advancing the start in the previous sub-period. This is possible in particular when all the servers requested during the previous period have successfully transmitted their data. Thus, the duration of a sub-period can be increased - the quality level required for the intervals that were previously part of the previous sub-period will be reduced, which will potentially give the client device more opportunities to request the transmission of useful data.

[0088] According to one or more exemplary embodiments, the duration of the sub-periods for a given server device is a function of the information characterizing the evolution of the quality level over time of this server device. The client device can then adapt the duration of the sub-periods. For example, if the server device has overall poor transmission quality, the client device can provide a duration of the late sub-periods that is longer than the duration of the initial sub-periods. In the latter case, this will increase the number of intervals meeting the quality criterion at the end of the period, increasing the probability of successful transmission of the useful data.

[0089] For purely illustrative purposes, a six-hour period will be divided, for example, into three one-hour periods, followed by two 1.5-hour periods.

[0090] Whether a server device has good or poor overall transmission quality can, for example, be assessed by comparing the average level of quality in the received information against a threshold. REFERENCE SIGNS

[0091] 1000 - Server device

[0092] 1001 - Processor

[0093] 1002 - Memory

[0094] 1003 - Data source

[0095] 1004 - Communication bus

[0096] 1005 - User Interface

[0097] 1006 - Bidirectional communication interface

[0098] 1007 - Display

[0099] 1008 - Software code

[0100] 1009 - Working memory

[0101] 1100 - Client Device

[0102] 1101 - Processor

[0103] 1102- Memory

[0104] 1103 - Mass storage

[0105]

[0106]

[0107]

[0108]

[0109]

[0110] 1104 - Communication Bus 1105 - User Interface 1106 - Bidirectional Communication Interface 1107 - Display 1108 - Software Code 1109 - Working Memory

Claims

Claims

1. A method of transmitting data between a data server device (1000) and a data receiving client device (1100) in a communication network, the server device comprising a memory (1002) comprising software code (1008) and a processor (1001) which, when it executes the software code, causes the server device to implement the method, the method comprising: - obtaining (201), over a first period of time, a plurality of measurements characterizing a quality of transmission between the client device and the server device; - determining (202), as a function of the measurements, information characterizing, as a function of time, a relative quality level of transmission during the first period; - transmitting (203) the information to the client device.

2. A method according to claim 1, the first period being subdivided into time intervals, the determination of the information comprising the determination (303) of a quality level for each interval on the basis of the measurements carried out for this interval in relation to one or more thresholds determined (302) from the measurements carried out over the whole of the first period.

3. Method according to claim 2, in which the threshold(s) are chosen between the highest and the lowest measurement value of the first period.

4. Method according to one of claims 1 to 3, in which the determination of the information and the transmission of this information are carried out periodically.

5. Method according to one of claims 1 to 4, in which the first period is one of: a time slot of a day, a day.

6. A method according to one of claims 1 to 5, comprising receiving a request to transmit data from the client device and transmitting the data in response to the request.

7. A method of transmitting data between at least one data server device (1000) and a data receiver device (1100) in a communication network, the receiver device comprising a memory (1102) comprising software code (1108) and a processor (1101) which, when it executes the software code, causes the receiving device to implement the method, the method comprising: - receiving (401), from a given server device, information characterizing an evolution of a relative quality level of transmission between the client device and said given server device during a first time period; - estimating (404) the relative quality level of transmission during a given time interval of the second period on the basis of said information corresponding to the same time interval of the first period, the time slot covered by the first period including at least the time slot of the second period; - deciding to send (408) a request for transmission of the data to the given server device during the given interval based on the comparison of the estimation for this interval with a quality threshold.

8. The method of claim 7, wherein the decision to send is made as time progresses during the second period, until (409) a send results in the successful receipt of said data.

9. Method according to one of claims 7 or 8, in which said quality threshold is a function of the placement of the given interval in the second period, the quality threshold having a maximum value at the start of the second period and decreasing (406) as time progresses in the second period towards a minimum value.

10. Method according to one of claims 7 to 9, in which the second period is one of - a part of a day corresponding to the same part of a day covered by the first day on a previous day; - the day following a day covered by the second period.

11. A method according to one of claims 7 to 10, comprising receiving information from a plurality of server devices, decision to send a request to a server device based on information received from that server device.

12. A server device (1000) comprising a memory (1002) comprising software code (1008) and a processor (1001) which, when executing the software code, causes the server device to implement the method according to one of claims 1 to 6.

13. A client device (1100) comprising a memory (1102) comprising software code (1108) and a processor (1101) which, when executing the software code, causes the client device to implement the method according to one of claims 7 to 11.

14. A system comprising a client device (1100) according to claim 13 and at least one server device (1000) according to claim 12.

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