Method for decoding a radio signal emitted by a connected household object

Abstract

The invention relates to a method for decoding (1) a radio signal (S) emitted by a connected home object, comprising the following steps: (E1) Reception of a radio signal (S) by a receiver in the central unit, (E2) demodulation and conversion of the radio signal into a frame (T) composed of dipoles (Ti), each consisting of a high or low level and a duration equal to that level; (E3j) For each protocol of a plurality of predetermined communication protocols, comparison of the frame to a predetermined pattern (Mj), comprising a succession of dipoles (Mj,k), each consisting of a high or low level and a duration equal to that level, associated with said protocol; (E4j) If a portion of the frame corresponds to the predetermined pattern associated with a protocol, called the detected protocol, decoding of the remainder of the frame based on that detected protocol. Figure to be published with the abstract: Fig. 1

Description

Title of the invention: Method for decoding a radio signal emitted by a connected household object

[0001] The invention relates to the field of home automation. More specifically, the invention relates to a method for decoding a radio signal emitted by a connected domestic object.

[0002] It is known to be able to communicate, via a centralized unit, with connected domestic objects, in particular for remote control purposes. This type of technology makes it possible, for example, to control, using a mobile phone, various equipment in a building such as a heating or air conditioning system, a security system, a watering system, an entertainment system or a lighting system.

[0003] However, the diversity of suppliers of connected equipment has led to the appearance of different wireless communication protocols, thus forcing users either to use only equipment from the same supplier in order to manage a single communication protocol, or to increase the number of centralized units in order to be able to manage different communication protocols.

[0004] This solution is not satisfactory, and there is thus a need for a method allowing a single centralized unit to communicate with connected domestic objects using different communication protocols. It is in particular necessary for this method to allow the centralized unit to decode a radio signal emitted by a connected domestic object and therefore to detect the communication protocol on which the coding of this radio signal is based.

[0005] The present invention is thus placed in this context and aims to meet this need.

[0006] For these purposes, the invention relates to a method of decoding by a centralized unit of a radio signal emitted by a connected household object, the method comprising the following steps: a. Reception of a radio signal by a receiver of the centralized unit, demodulation of said received radio signal and conversion of the demodulated radio signal into a frame composed of a succession of doublets each formed of a high or low level and of a duration of this level; b. For each protocol of a plurality of predetermined communication protocols, comparison of at least a portion of the frame to a predetermined pattern, comprising a succession of doublets each formed of a high or low level and a duration of this level, associated with said protocol; c. If said portion of the frame matches the predetermined pattern associated with a protocol, said detected protocol, of said plurality of communication protocols, decoding the remainder of the frame from this detected protocol.

[0007] It is thus understood that the invention aims to temporally compare a frame obtained from the demodulation of a radio signal received by the centralized unit with several predetermined patterns, each corresponding to a part of a data frame defined beforehand in one of the protocols of the plurality of communication protocols, and which is consequently known to be necessarily present in the data frames transmitted by a connected object using this protocol. In other words, the predetermined pattern associated with a communication protocol will necessarily be present in a frame obtained from the demodulation of a radio signal transmitted by a connected object using this protocol.In the case where this protocol is part of the plurality of communication protocols, it is thus possible to detect this protocol using this temporal comparison, without it being necessary to first understand the frame, and therefore to then decode the rest of the frame. The invention thus achieves its objective, namely to allow the centralized unit to communicate with connected domestic objects using different communication protocols.

[0008] The plurality of communication protocols may for example include one or more of the following communication protocols: Z-Wave, Blyss, ARW, EnOcean, ZigBee.

[0009] In one embodiment of the invention, the reception step comprises a step of listening to a communication channel by the receiver to receive said radio signal, a step of determining a reception power level of said radio signal received on this channel, a step of comparing this determined reception power level with a threshold value, the step of demodulating said received radio signal being implemented only if the determined reception power level is greater than this threshold value. According to this characteristic, for performance purposes, the demodulation of the received radio signal is only carried out when a radio signal, and not noise, is actually received.

[0010] For example, the threshold value may be determined from a sliding average of the power of the radio signal received on the channel, in particular from the sliding average of the power of a background noise of the channel, estimated in the absence of a radio signal whose power level in reception would be higher than the threshold value previously determined.

[0011] Demodulation of a radio signal means so-called baseband demodulation, i.e. extraction, from the radio signal, of a signal modulating a carrier wave to form said radio signal. Advantageously, the received radio signal may be demodulated, by default, using amplitude shift keying, also called ASK (from the English Amplitude Shift Keying), and, if the reception power level is constant, using frequency shift keying, also called FSK (from the English Frequency Shift Keying). This characteristic makes it possible to quickly detect the type of modulation used in the communication protocol on which the received radio signal is based. The conversion of the demodulated radio signal into a frame advantageously includes a step of sampling the demodulated radio signal, each doublet thus being sequentially obtained at the end of the sampling.

[0012] Preferably, the steps of listening, determining the reception power level and comparing the determined reception power level with a threshold value may be periodically repeated for different communication channels until the determined reception power level is greater than this threshold value. In other words, according to this characteristic, the listening channel is changed regularly so as in particular to be able to scan all the channels used in home automation. For example, the receiver may change its reception frequency periodically between the frequencies 433.92 MHz and 868.30 MHz.

[0013] If desired, the total renewal period of a communication channel, i.e. the period separating two listenings of the same communication channel, may be less than the smallest total pattern duration, in particular obtained by the sum of the doublet durations of this pattern, of all the patterns associated with the protocols of said plurality of predetermined communication protocols. This ensures that the remainder of the frame can be decoded in full. Alternatively, the total renewal period of a communication channel, i.e. the period separating two listenings of the same communication channel, may be less than the greater of the values ​​between the small total pattern duration and the duration of a previously received frame. This characteristic makes it possible to ensure that the next frame to be received will be decoded, in the case where the portion of the received frame, which must correspond to a pattern, is truncated.This takes advantage of the fact that a connected household object repeatedly sends the same radio signal.

[0014] In one embodiment of the invention, for each protocol of said plurality of predetermined communication protocols, the predetermined pattern associated with this protocol corresponds to a predetermined start of a data frame encoded according to this protocol. For example, this predetermined start may correspond to a preamble, a header and / or a synchronization word provided at the start of each data frame. data encoded according to this protocol. In other words, the comparison step of the method according to the invention is a step of detecting the start of a frame.

[0015] Advantageously, for each protocol of said plurality of predetermined communication protocols, the comparison step comprises: a. an initial step of initializing an index on the first doublet of the pattern associated with this protocol, notably implemented at the start of the conversion of the demodulated radio signal, and b. for each doublet of the frame, in particular resulting successively from the conversion of the demodulated radio signal, a step of comparing this doublet of the frame with the indexed doublet of the pattern, in which: i. if this doublet of the frame corresponds to the indexed doublet of the pattern, the index is incremented and the comparison step is repeated for the next doublet of the frame; ii. if this doublet of the frame is different from the indexed doublet of the pattern and if the index is positioned beyond the first doublet of the pattern, the index is reset to the first doublet of the pattern and the comparison step is repeated for this doublet of the frame; iii. if this doublet of the frame is different from the indexed doublet of the pattern and if the index is positioned on the first doublet of the pattern, the comparison step is repeated for the next doublet of the frame.

[0016] Where appropriate, the comparison step is repeated, for each protocol of the plurality of communication protocols, until the index reaches the last doublet of the pattern, the portion of the frame, formed by all the doublets corresponding to the doublets of the pattern, then corresponding to the pattern. It is therefore understood that when, for one of the protocols, the maximum index of the pattern associated with this protocol is reached, this means that this pattern is present in the frame and therefore that the protocol that was used in the received radio signal has been detected.

[0017] In the comparison step, for example, the level of the frame doublet is compared to the indexed doublet of the pattern and the duration of the level of the frame doublet is compared to the duration of the level of the indexed doublet of the pattern.

[0018] Advantageously, in the step of comparing the frame doublet to the indexed doublet of the pattern, the duration of the frame doublet may be compared to a duration interval, determined as a function of the duration of the indexed doublet of the pattern. This duration interval may thus be a tolerance range, centered on the duration of the indexed doublet of the pattern, and therefore the limits may be determined in particular as a function of the sampling frequency used for the demodulation of the radio signal. thus allows the method according to the invention to be robust in the face of errors introduced by this sampling.

[0019] Advantageously, the step of decoding the remainder of the frame can be carried out on the fly, each doublet of the frame resulting from the conversion of the demodulated radio signal being successively decoded using the detected protocol. Decoding a frame means the transformation of this frame into binary data.

[0020] According to one embodiment of the invention, the method may comprise a step of detecting the end of the frame. This may, for example, be a step of detecting a time interval, called an “inter-frame”, in which the frame has a doublet formed by a low state and a duration greater than a threshold value defined in the detected protocol. Alternatively, this may be a step of detecting a predetermined frame conclusion defined in the detected protocol. As a further variant, this may be a step of detecting a size or duration of the frame defined in the detected protocol.

[0021] Advantageously, the decoding method may comprise a step of extracting data contained in the decoded frame using the detected protocol. This data extraction step may, for example, be implemented at the end of the step of detecting the end of the frame.

[0022] The invention also relates to a centralized wireless communication unit with a plurality of connected household objects, the centralized unit comprising a radio signal receiver and being arranged to implement the method according to the invention.

[0023] Advantageously, the receiver may comprise several sub-receivers each capable of demodulating a radio signal according to a distinct modulation mode, for example according to amplitude shift keying, also called ASK (from the English Amplitude Shift Keying) or according to frequency shift keying, also called FSK (from the English Frequency Shift Keying). Alternatively, the receiver may be a single receiver capable of simultaneously demodulating a radio signal according to different modulation modes.

[0024] Advantageously, the centralized unit may comprise, for each protocol of said plurality of communication protocols, a state machine capable of implementing the comparison and decoding steps. Advantageously still, the centralized unit may comprise a microcontroller arranged to implement the comparison, decoding, and where appropriate, data extraction steps. Where appropriate, one or more computer programs comprising program code forming said state machines may be recorded on the microcontroller. If desired, the microcontroller may be arranged to control the receiver so as to modify the listening channel of the receiver.

[0025] The present invention is now described with the aid of examples which are purely illustrative and in no way limitative of the scope of the invention, and from the appended drawings, drawings in which the various figures represent:

[0026] [Fig.l] represents, schematically and partially, a method of decoding a radio signal according to an embodiment of the invention;

[0027] [Fig.2] represents, schematically and partially, an example of carrying out a step of the method of [Fig.l]; and

[0028] [Fig.3a] represents, schematically and partially, a stage of the process of [Fig.l];

[0029] [Fig.3b] represents, schematically and partially, a later stage of the process of [Fig.l];

[0030] [Fig.3c] represents, schematically and partially, a later stage of the process of [Fig.l];

[0031] [Fig.3d] represents, schematically and partially, a later stage of the process of [Fig.l];

[0032] [Fig.3e] represents, schematically and partially, a later stage of the process of [Fig.l];

[0033] [Fig.3f] represents, schematically and partially, a later stage of the process of [Fig.l];

[0034] [Fig.3g] represents, schematically and partially, a later stage of the process of [Fig.l];

[0035] [Fig.3h] represents, schematically and partially, a later stage of the process of [Fig.l];

[0036] [Fig.3i] represents, schematically and partially, a later stage of the process of [Fig.l];

[0037] [Fig.3j] represents, schematically and partially, a later stage of the process of [Fig.l].

[0038] In the following description, elements that are identical, by structure or by function, appearing in different figures retain, unless otherwise specified, the same references.

[0039] [Fig.l] shows an exemplary embodiment, according to the invention, of a method 1 for decoding, by a centralized home automation unit, a radio signal S emitted by a connected domestic object, the protocol having enabled the coding of this radio signal S being unknown. The centralized unit comprises a receiver and a microcontroller (not shown).

[0040] The method 1 comprises a step El of reception, by the receiver of the centralized unit, of a radio signal S emitted by the domestic object connected on a given communication channel. More precisely, step El comprises a step Eli of listening of said communication channel for a given duration, for example of the order of a millisecond, and determining a power level in RSSI reception of a radio signal received by the receiver from this communication channel for this given duration.

[0041] Step E1 comprises, following step E11, a step E12 of comparing the RSSI level to a threshold value SRSsi. In the example described, the threshold value SRSsi may be determined by the receiver by calculating the sliding average, established over a sliding time interval of predetermined size, of the RSSI power level of the radio signal that it picks up on this communication channel.

[0042] The result of this comparison is provided to the microcontroller. If, at the end of the comparison step E12, the RSSI level is lower than the threshold value SRSsi, the microcontroller concludes that there is no radio signal emitted by a domestic object connected to this channel. The microcontroller then controls the receiver to repeat steps E11 and E12 on another communication channel. The receiver thus periodically scans different communication channels until the RSSI level is higher than the threshold value SRSsi, or is higher than the sum of the threshold value SRSsi, a constant margin, for example 6 dB, and a dynamic margin, the microcontroller then detecting the presence of a radio signal actually emitted by a domestic object connected to the listening channel.

[0043] In the example described, the receiver alternates listening to two communication channels operating on the frequencies 433.92 MHz and 868.30 MHz. It may be envisaged, without departing from the scope of the present invention, to alternate listening to more than two communication channels and / or to listen to channels operating on different frequencies than those mentioned.

[0044] At the end of step E12, when the RSSI level is greater than the threshold value SRSsi, the microcontroller proceeds, in a step E2 of method 1, to a demodulation of the radio signal S received in baseband and to a conversion, by sampling, of the demodulated signal into a frame T composed of a succession of doublets T; each formed of a high or low level and of a duration of this level. In [Fig.l], the duration of the level of each doublet T; of the frame T has been reported at the right of this level.

[0045] It should be noted that in the field of home automation, the most commonly used types of modulation are ASK amplitude shift keying and FSK frequency shift keying. Although the protocol defining the type of modulation used for the received radio signal S is still unknown at this stage, it is possible to detect this type of modulation used as a function of the RSSI level of the radio signal, which is constant for FSK type modulation and is variable for ASK type modulation. Thus, by default, in step E2, a ASK demodulation of the radio signal S and on the contrary, FSK demodulation will be carried out if the RSSI level of the radio signal S is constant.

[0046] As is known, the various communication protocols used in home automation employ different types of coding of the binary data to be transmitted. The binary data transported by the radio signal S can thus be coded for example by NRZ (Non Return to Zero) coding, by Manchester coding or by other types of coding. Thus, the frame T obtained at the end of step E2 represents the coding of the binary data transported by the radio signal S, without this coding being known. At this stage, it is therefore not possible to use this frame T to decode this binary data, and it is necessary to determine which protocol the radio signal S is based on.

[0047] For these purposes, a plurality of communication protocols, known and frequently used in home automation, was selected and for each of these protocols, a start of frame was identified, formed of a set of bits, systematically present in each data frame that can be transmitted according to this protocol. It can thus be a frame preamble and / or a synchronization word that it is necessary to add, according to this protocol, upstream of binary data to be transmitted. Each of these start of frames was then converted, by means of NRZ, Manchester, or other coding, defined in its associated protocol, into a predetermined pattern Mj composed of a succession of doublets Mj, k each formed of a high or low level and a duration of this level. These patterns Mj were loaded into a memory of the microcontroller of the centralized unit.

[0048] Without this being limiting, [Fig.l] thus represents three patterns Mb M2 and M3. It will be noted that, without this being limiting, this determination of a predetermined pattern can be carried out for the following protocols: Z-Wave, Blyss, ARW, EnOcean, ZigBee.

[0049] For each of these patterns Mj, a temporal comparison of the frame T with this pattern Mj is thus carried out simultaneously in steps E3j. It is thus understood that when one of the patterns Mj is identified within the frame T, it is possible to conclude that it is the protocol associated with this pattern Mj which was used for the transmission of the radio signal S. In other words, it is possible to detect this protocol and to use it to decode the rest of the frame which follows this pattern Mj.

[0050] It should be noted that the total renewal period of step E1, that is to say the time interval separating two listenings of the same communication channel, is advantageously less than the smallest of the values ​​between the smallest duration of the patterns Mj and the duration of a frame T previously obtained.

[0051] In a step E4j, the remainder of the frame T is thus decoded using the detected protocol, the doublets T; being decoded on the fly, successively one after the other, so as to recover the binary data B transported by the radio signal S.

[0052] This step E4j is carried out until an end of the frame T is detected, in a step E5j. The detected protocol may for example specify a time interval, called “inter-frame” which must separate two successive frames, or a frame conclusion or a frame size. When this end of frame is detected, the complete binary data B can then be analyzed using the detected protocol, in a step E6j, to extract the data transmitted by the connected domestic object, the decoding operations then being completed.

[0053] [Fig.2] shows an exemplary embodiment according to the invention of steps E3j and E4j. [Fig.3a] to [Fig.3i] represent the frame T of [Fig.l] as well as the patterns Mi to M3 of this [Fig.l] at different times of these steps E3j and E4j, in order to illustrate the operation of the method.

[0054] For each protocol, and therefore in each of the steps E3j, during the detection of the radio signal S by the receiver, or during the start of the conversion of this radio signal into the frame T, an index k is initialized in a step E31, which is positioned on the first doublet Mj i of the pattern Mj associated with this protocol.

[0055] Each of the doublets T; of the frame T is then processed successively in a comparison step E32.

[0056] Each doublet T; of the frame which is processed in step E32 (identified by an arrow below the frame T) is thus compared to the indexed doublet Mj, k (identified by an arrow below the pattern Mj). It is thus verified on the one hand whether the level of the doublet T; is identical to the level of the indexed doublet Mj k. It is also verified on the other hand whether the durations of these levels are substantially identical. It should be noted that the duration of the level of the doublet T; may include an error introduced by noise present on the transmission channel of the radio signal S, by the quality of the receiver or even by the sampling carried out during step E2. The duration of the level of the doublet T; is thus compared to a tolerance range centered on the duration of the level of the indexed doublet Mj, k and whose limits are determined in particular as a function of factors relating to the noise of the transmission channel, to the quality of the receiver and to the sampling frequency used in step E2.Without limitation, in the example described, the margin of error for a duration of 105 ps is 30 ps, ​​that for a duration of 210 ps is 40 ps and that for a duration of 315 ps is 50 ps.

[0057] At the end of this comparison, in a step E33a: if the doublet T; corresponds to the indexed doublet Mj k, the index k is incremented to position it on the following doublet Mj, k+i of the pattern Mj. If the index k is less than or equal to the size kmax of the pattern Mj, then repeats step E32 for the next doublet of frame T, namely doublet Ti+1.

[0058] On the contrary, in a step E33b: if the first doublet Ti is different from the indexed doublet Mj and the index k is strictly greater than 1 (and is therefore positioned beyond the first doublet Mji of the pattern), the index k is reset on the first doublet Mj i of the pattern Mj and the step E32 is repeated for the doublet T; of the frame T.

[0059] Finally, in a step E33c: if the first doublet Ti is different from the indexed doublet Mj,k, and the index k is equal to 1 (and is therefore positioned on the first doublet Mj,i of the pattern), step E32 is repeated for the following doublet of the frame T, namely the doublet Ti+i.

[0060] [Fig.3a] thus represents the frame T and the three patterns Mb M2 and M3, as well as the position of the indexes k for each of these patterns during the comparison steps E32 carried out for the first doublet Ti of the frame T. In this figure, the indexes k have just been initialized and are therefore all equal to 1. It can thus be seen that the first doublet Ti corresponds to each of the first doublets Mi, i, M2, i and M3, b Step E33a is thus implemented, each of the indexes k is incremented, without however reaching the maximum size of the patterns Mb M2 and M3 and the steps E32 are therefore repeated for the second doublet T2 of the frame T.

[0061] As shown in [Fig.3b], none of the second doublets Mi,2, M2,2 and M3,2 corresponds to the second doublet T2 of the frame T, since the duration of this doublet (221 ps) is not included in one of the tolerance ranges of the durations of these second doublets Mi,2, M2,2 and M3,2 (namely 75 ps - 135 ps for Mi 2 and M3 2 and 265 ps - 365 ps for M2 2). At the end of the comparison, step E33b is implemented, and the indexes k are therefore reset and steps E32 are repeated for the second doublet T2 of the frame T.

[0062] As shown in [Fig.3c], the second doublet T2 of the frame T also does not correspond to the first doublets Mi, b M2, i and M3, b the level of the second doublet being different. At the end of the comparison, step E33c is implemented, and steps E32 are repeated for the third doublet T3 of the frame T (as shown in [Fig.3d]).

[0063] [Fig.3e] and [Fig.3f] show that steps E32 are repeated until reaching doublet T7 of frame T. However, it can be seen that doublets T7 to Tu of frame T correspond to doublets Mi, i to Mi, 5 of the first pattern Mi. From then on, steps E33a are successively implemented, at the end of comparisons E32 for each of these doublets Mi, i to Mi, 5, so that the index k of the first pattern Mi reaches the end of this pattern ([Fig.3e]. It is thus possible for the microcontroller to conclude that this first pattern Mi is present in frame T and therefore to detect that it is the protocol associated with this pattern Mi which was used for the emission of the radio signal S. It is then possible to move on to the decoding step E4j.

[0064] In this decoding step E4j, and similarly to the comparison step E3j, each of the doublets T; of the frame T following the last doublet of the frame T which was detected as being part of the pattern Mb, namely the doublet Tu, is successively compared to doublets Wjjk of coding symbols Wj of binary data according to the coding mode, NRZ, Manchester or other, specified in the detected protocol. Thus, in a manner equivalent to the comparison step E3j, an index k is thus initialized at the start of each of the symbols Wj, and each of the doublets Ti of the frame is compared on the fly to the doublet Wj, k indexed by each of these symbols Wj, by incrementing or not the indexes k according to this comparison, a symbol Wj being detected in the frame T when the index k of this symbol reaches the last doublet of this symbol.

[0065] [Fig.3g] to [Fig.3j] thus represent the first decoding steps E4j of the frame T represented in [Fig.3a] to [Fig.3g]. In this example, without this being limiting, the protocol detected at the end of step E3i specifies a coding of the binary data according to a Manchester code using the symbols Wi and W2 represented in these [Fig.3g] to [Fig.3j].

[0066] We can thus see that at the end of [Fig.3h], the symbol Wi has been detected in the frame T, at the level of the symbols Tn and Tn, thus meaning that the first binary data of the radio signal S following the preamble is a 0.

[0067] Similarly, at the end of [Fig.3j], the symbol Wi has again been detected in the frame T, at the level of the symbols Ti 4 and Ti 5, thus meaning that the second binary data of the radio signal S is a 0. It should be noted that in the comparison carried out in the decoding steps E4j, only the level of the doublet T; of the frame T and the indexed doublet Wjjk are compared. When the duration of a doublet T; is substantially outside the tolerance range defined for the duration of the indexed doublet Wj >k but the levels of these doublets correspond (as in [Fig.3j]), the duration of the indexed doublet Wj >k is then subtracted from the duration of the doublet T; to consider the level of the doublet T; and the result of this subtraction as a new doublet of the frame T to be the subject of the following comparison.

[0068] It should be noted that when the decoding of step E4i reaches the doublet Ti8, this doublet will be detected in step E5j of [Fig.l] as corresponding to an “inter-frame” time, thus signifying that the decoding of the frame T is thus finished, all of the binary data detected during steps E4i can then be analyzed to extract therefrom, in step E6i, the data transmitted by the connected domestic object.

[0069] The preceding description clearly explains how the invention makes it possible to achieve the objectives it has set itself, and in particular by proposing a method for decoding a radio signal emitted by a connected domestic object which temporally compares a frame resulting from the demodulation of this radio signal to a plurality of predetermined patterns each associated with a given communication protocol. In this way, it is possible to detect which communication protocol has been used and to decode this frame.

[0070] In any event, the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to all equivalent means and to any technically effective combination of these means.

Claims

Claims

1. Method for decoding (1) by a centralized unit a radio signal (S) emitted by a connected domestic object, the method comprising the following steps: • (El) Reception of the radio signal (S) by a receiver of the centralized unit, (E2) demodulation of said received radio signal and conversion of the demodulated radio signal into a frame (T) composed of a succession of doublets (Tj) each formed of a high or low level and a duration of this level; • (E3j) For each protocol of a plurality of predetermined communication protocols, comparison of at least a portion of the frame with a predetermined pattern (Mj), comprising a succession of doublets (Mj>k) each formed of a high or low level and a duration of this level, associated with said protocol;• (E4j) If said portion of the frame corresponds to the predetermined pattern associated with a protocol, called detected protocol, of said plurality of communication protocols, decoding the remainder of the frame from this detected protocol; characterized in that the reception step (El) comprises a step of listening (El 1) to a communication channel by the receiver to receive said radio signal (S), a step of determining a reception power level (RSSI) of said radio signal received on this channel, a step of comparing (E12) this determined reception power level to a threshold value (SRSsi), the step of demodulating (E2) said received radio signal being implemented only if the determined reception power level is greater than this threshold value.;

2. Decoding method (1) according to the preceding claim, in which the steps of listening (Eli), determining the reception power level (RSSI) and comparing (E12) the determined reception power level with a threshold value (Srssi) are periodically renewed for different channels of communication until the determined receive power level is higher than this threshold value.

3. Decoding method (1) according to the preceding claim, wherein the total renewal period of a communication channel is less than the smallest total pattern duration of all the patterns (Mj) associated with the protocols of said plurality of predetermined communication protocols.

4. Decoding method (1) according to one of the preceding claims, in which, for each protocol of said plurality of predetermined communication protocols, the predetermined pattern (Mj) associated with this protocol corresponds to a predetermined start of a data frame encoded according to this protocol.

5. Decoding method (1) according to the preceding claim, in which, for each protocol of said plurality of predetermined communication protocols, the comparison step (E3j) comprises: • (E31) an initial step of initializing an index (k) on the first doublet (Mj i) of the pattern associated with this protocol, and • for each doublet (Tj) of the frame (T), a step of comparing (E32) this doublet of the frame to the indexed doublet (Mjjk) of the pattern, in which: • (E33a) if this doublet (T; j) of the frame corresponds to the indexed doublet of the pattern, the index is incremented and the comparison step is repeated for the next doublet (T; +[) of the frame; • (E33b) if this doublet (T;) of the frame is different from the indexed doublet of the pattern and if the index is positioned beyond the first doublet of the pattern, the comparison step is reinitialized. the index on the first doublet of the pattern and we repeat the comparison step for this doublet (Tj) of the frame;• (E33c) if this doublet (T;) of the frame is different from the indexed doublet of the pattern and if the index is positioned on the first doublet of the pattern, we repeat the comparison step for the following doublet (T; +i) of the frame; the comparison step being repeated, for each protocol of the plurality of communication protocols, until the index reaches the last doublet of the pattern, the portion of the frame, formed by all the doublets corresponding to the doublets of the pattern, then corresponding to the pattern.

6. Decoding method (1) according to the preceding claim, in which, in the step of comparing (E32) the doublet (T;) of the frame (T) to the indexed doublet (Mjjk) of the pattern (Mj), the duration of the doublet of the frame is compared to a duration interval determined as a function of the duration of the indexed doublet of the pattern.

7. Decoding method (1) according to one of claims 4 to 6, characterized in that it comprises a step of detecting (E5j) the end of the frame (T).

8. Decoding method (1) according to one of the preceding claims, characterized in that it comprises a step of extracting (E6j) data contained in the frame (T) decoded using the detected protocol.

9. Centralized unit for wireless communication with a plurality of connected household objects, the centralized unit comprising a radio signal receiver and being arranged to implement the method (1) according to one of claims 1 to 8.

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