Methods for controlling radio frequency communications receivers

Abstract

Methods for controlling radio frequency communications receivers The present description relates to a method for controlling a radio frequency communications receiver (102) in which intervals between the reception of a header (Header SeqNr N) of a data packet and an acknowledgment sent by the receiver are constant, a method in which, once a packet has been correctly received, circuits of the receiver are put on standby for a duration corresponding to said interval after each reception of a header of the same rank as that of the correctly received packet. Figure for the abstract: Fig. 2

Description

Title of the invention: Methods for controlling radiofrequency communications receivers Technical field

[0001] The present description relates generally to radio frequency communications systems. The present description relates more particularly to radio frequency communications receivers. Prior art

[0002] Communications between a transmitter and a receiver of radio frequency communications can be unstable. Common communication protocols therefore provide for the repeated sending of the same data packet by the transmitter until it is received by the receiver.

[0003] Current protocols, however, result in significant energy consumption by the receiver. Summary of the invention

[0004] There is a need for improvement of radio frequency communication methods and receivers.

[0005] There is in particular a need for a radiofrequency communication method making it possible to save the energy consumed by the receivers as well as for receivers implementing such a method.

[0006] One embodiment overcomes all or part of the drawbacks of known methods and receivers.

[0007] One embodiment provides a method for controlling a radio frequency communications receiver in which intervals between the reception of a data packet header and an acknowledgment sent by the receiver are constant, in which method, once a packet has been correctly received, circuits of the receiver are put on standby for a duration corresponding to said interval after each reception of a header of the same rank as that of the correctly received packet.

[0008] One embodiment provides a radio frequency communications receiver in which intervals between the reception of a data packet header and an acknowledgment sent by the receiver are constant, in which receiver, once a packet has been correctly received, circuits are put on standby for a duration corresponding to said interval after each reception of a header of the same rank as that of the correctly received packet.

[0009] According to one embodiment, after each reception of a header of a rank different from that of the correctly received packet, said receiver circuits remain active for at least minus a part of the corresponding interval.

[0010] According to one embodiment, the data packet of each of the intervals is arranged in a protocol data unit.

[0011] According to one embodiment, the intervals have a size greater than a predetermined maximum size of protocol data units.

[0012] According to one embodiment, each of the intervals comprises a clock adjustment duration between the protocol data unit and the acknowledgment sent by the receiver.

[0013] According to one embodiment, during the adjustment period, said receiver circuits are put on standby.

[0014] According to one embodiment, said receiver circuits are active for sending the acknowledgment.

[0015] One embodiment provides a radio frequency communication system comprising: - a first communication module configured to transmit data packets having a header indicating their respective rank and, - a second communication module configured to implement the method as described above.

[0016] According to one embodiment, the first module is also configured to implement the method as described above.

[0017] According to one embodiment, the first module and the second module are identical.

[0018] According to one embodiment, the first and / or the second modules comprise a radiofrequency signal transmission block and a radiofrequency signal reception block.

[0019] According to one embodiment, the signal transmission block and the reception block, of the first and / or the second module, are connected to a respective antenna via a switch connecting the antenna sometimes to the transmission block, sometimes to the reception block.

[0020] According to one embodiment, the first and / or the second modules comprise a data buffer storage module configured to store an acknowledgment and / or data packets. Brief description of the drawings

[0021] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments and implementations made without limitation in relation to the attached figures among which:

[0022] [Fig.l] very schematically represents an example of a radiofrequency communication system of the type to which the described embodiments apply;

[0023] [Fig.2] illustrates, in the form of a flowchart, a mode of implementation of a radiofrequency communication method; and

[0024] [Fig.3] illustrates, in the form of a timing diagram, a mode of implementation of a radiofrequency communication method. Description of the embodiments

[0025] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0026] For the sake of clarity, only the steps and elements useful for understanding the embodiments and implementations described have been represented and are detailed.

[0027] Unless otherwise specified, when referring to two elements connected between them, it means directly connected without intermediate elements other than conductors, and when we refer to two elements connected (in English "coupled") between them, it means that these two elements can be connected or be linked by means of one or more other elements.

[0028] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made unless otherwise specified to the orientation of the figures.

[0029] Unless otherwise specified, the expressions "approximately", "approximately", "sen "possibly", and "of the order of" mean within 10%, preferably within 5%.

[0030] [Fig.l] represents, in a very schematic manner, an example of a radiofrequency communication system of the type to which the described embodiments apply.

[0031] The system 100 comprises a first 104 and a second 102 communications module configured to exchange data bidirectionally.

[0032] In the example shown, the module 102 and the module 104 are each configured to be used either in a data transmission mode or in a data reception mode. However, it is possible to envisage that one of the modules is solely a data transmitter and the other module is solely a data receiver.

[0033] In the present description, the data transmitted are referred to interchangeably by the terms “data” and “data packets”.

[0034] The module 102 and the module 104 each comprise a radiofrequency signal transmission block (Transmitter) 132, respectively 124, a radiofrequency signal reception block (Receiver) 122, respectively 134, connected to an antenna, 172, respectively 174, via a switch connecting the antenna sometimes to the transmission block, sometimes to the reception block. The transmission and reception blocks of each module are connected to a time counter (TIMER) 112, respectively 114, allowing among other things to synchronize them or to count the different times allocated to each data transmission frame, as provided by the radiofrequency protocol implemented. The radiofrequency signal transmission block 132, respectively 124, and the radiofrequency signal reception block 122, respectively 134, of each module 102, 104, are connected to each other via a data buffer storage module (Receive Packet PDU buffer, in the case of data reception, Transmit Packet PDU buffer, in the case of data transmission) 142, respectively 144.The data received by the receiving block and transmitted to the buffer storage module includes, for example, an acknowledgment of data receipt from the other module.

[0035] By default, both modules are in data receiving or listening mode. When one of the two modules wishes to transmit data, it is switched to data transmission mode.

[0036] The radiofrequency communication protocol implemented comprises successive frames of constant duration. These frames are formed for example of a first duration or field during which a data header is sent. The header contains for example a data rank and indexes the data or data packets according to their rank, in other words according to their sequence number (sequence N, sequence N+1, etc.). The first duration is followed for example by the sending of a protocol data unit (PDU), comprising the data packets, then by a possible response waiting period after which a similar frame or a frame corresponding to another protocol data unit rank is sent. The data packets sent, in other words transmitted, for adjacent frames, may be identical if the reception of these data packets is not confirmed by the module which is supposed to receive them or if the reception is not effective.In another example, the communication protocol provides that, during several successive adjacent frames, data of the same rank is returned whether it is received correctly or not. In one example, when the transmitted packets are received correctly, an acknowledgment is for example sent to the sending module and the data sent in the next frame is that of the next protocol data unit rank.

[0037] The data or data elements contained in the protocol data unit contain, for example, the data and data control elements such as a cyclic redundancy code (CRC) or a checksum.

[0038] The receiver module first reads the header of each data packet to determine the rank of this data packet. When the data packets of a given rank are correctly received by the receiving module, the transmitting block of the receiving module sends an acknowledgment to the other module. If the acknowledgment is not received within the corresponding expected interval by the module that sent the data packets of the same rank, the sending module retransmits data packets of the same rank until it receives the corresponding acknowledgment. For example, as long as the sender does not receive an acknowledgment from the receiver attesting to the correct reception of the data of a given rank, the data of the same rank is resent.

[0039] The time interval between the reception of the header by the receiver and the sending of the acknowledgment of receipt by this receiver will be referred to as "interval". This interval is fixed by the transmission protocol implemented by the transmission-reception system and is constant.

[0040] Each time data packets are sent by the transmitter module, circuits of the receiver read and decode the header of the received data packet. These circuits remain active until the receiver sends the acknowledgment of receipt, possibly with a temporary deactivation of the receiver between the reception of the protocol data unit and the sending of the acknowledgment of receipt.

[0041] In the case where the transmitter has already sent data of a given rank and has not received the acknowledgment of receipt, then this same data packet will be resent and the receiver will remain active to receive a data packet which has therefore already been received in the first place. In this case, the fact that the receiver circuits remain active results in a priori unnecessary energy consumption while the useful data have themselves already been received correctly.

[0042] According to the embodiments described, provision is made to implement a standby or deactivation of receiver circuits for a duration corresponding to the constant interval once a data packet has been correctly received and after each reception of a header of the same rank as that of the correctly received packet. This considerably reduces the energy consumption at the receiver.

[0043] [Fig.2] illustrates, in the form of a flowchart, a mode of implementation of a radiofrequency communication method.

[0044] Steps 202, 204, 210, 212, 214, 216 and 218 describe an operation of the receiver according to which a protocol data unit of a given rank is received by the receiver for the first time.

[0045] Steps 206, 207 and 209 describe an operation of the receiver when a protocol data unit of a given rank has already been received by the receiver at least once.

[0046] In a step 202 (Header received correctly), it is checked whether the header of the packet re- received was received correctly by the receiver.

[0047] If yes, branch “Y”, the receiver sends an acknowledgment and the method goes to step 204 (SeqNr = Previous correctly receive PDU packet SeqNr).

[0048] If no, branch “N”, the method goes to step 216 (Send Not Acknowledge).

[0049] In step 204, the rank of the data packet linked to the received header is read and is noted for example SeqNr. If the rank SeqNr is the same as that of the previously received header then the “Y” branch is taken towards step 206 (PDU packet already correctly received).

[0050] Otherwise, the “N” branch is followed to implement step 210 (Receive and store PDU payload).

[0051] In step 210, the data packet contained in the protocol data unit is received, read and stored by circuits of the receiver for example to the buffer 142.

[0052] Then, the receiver is stopped or put on standby during a step 212 (Stop receive) between the end of reception of the protocol data unit and the sending of the acknowledgment of receipt by the receiver.

[0053] Following step 212, a step 214 (PDU payload received correctly) consists of checking whether the protocol data unit of rank SeqNr has been correctly received. If not, (branch N), a step 216 (Send Not Acknowledge) is carried out by sending, from the receiver, a message indicating the incorrect reception of the protocol data unit. If so, (branch “Y”), a step 218 (Send Ack-nowledgement) is carried out by sending an acknowledgment of receipt with the receiver.

[0054] In step 206, if the protocol data unit of rank SeqNr has already been received correctly during the previous interval, then the branch "Y" is taken up to step 207 (Stop receive). In this case, the protocol data unit of the same rank is not stored again in the buffer 142.

[0055] Otherwise, branch “N” is followed to implement step 210.

[0056] In step 207, circuits of the receiver or the entire receiver are disabled or put on standby and step 209 (Count remaining time) is implemented.

[0057] In step 209, a counter, for example counter 112, determines the duration during which circuits of the receiver or the receiver as a whole remain deactivated until an acknowledgment is sent. This deactivation duration begins, for example, after reading the header.

[0058] The deactivation duration is for example constant and can be predetermined in the communication protocol as a function of a maximum length of the authorized protocol data unit. The deactivation duration begins for example after reading the header. The predetermined deactivation duration is for example greater than the maximum length of the authorized protocol data unit while being less than the duration provided in the protocol between the end of the header and the sending of the acknowledgment of receipt. The deactivation duration includes, for example, an adjustment duration (Delay to Ack), after the duration corresponding to the reception of the maximum length (duration) of the protocol data unit allowed by the protocol, until the time provided in the protocol for sending the acknowledgment of receipt. The adjustment duration is used, for example, to take into account variations in clock frequency between the receiver and the transmitter, which can be of the order of 80 parts per million (ppm). The duration corresponding to the length of the protocol data unit is obtained by multiplying the length of the protocol data unit, expressed in bits, by the bit rate.

[0059] In another example, the deactivation duration begins after reading the header and has a duration, counted from the end of the header, corresponding to the length of the protocol data unit of the same rank that has already been received in a previous interval. In this example, the receiver can be woken up or reactivated after the duration corresponding to the length of the protocol data unit of the same rank that has already been received in a previous interval and after, for example, an adjustment duration (Delay to Ack) until the time provided in the protocol for sending the acknowledgment.

[0060] At the end of step 209, step 218 is implemented by sending an acknowledgment with the receiver.

[0061] Steps 206 to 209 make it possible to receive the protocol data unit of a given rank only once, which makes it possible to save the energy consumed by the receiver.

[0062] [Fig.3] represents a timing diagram of a communication method according to one embodiment.

[0063] More precisely, [Fig.3] represents an example of radiofrequency communication between two communication modules (Transmitter side, Receiver side).

[0064] At a time t0 until a time t1, the header (Header SeqNr N) of a protocol data unit (PDU payload) of rank N is sent by a module in transmitter mode to a module in receiver mode.

[0065] Between time t1 and a later time t2, said protocol data unit is also sent by the transmitter and correctly received by the receiver.

[0066] Between time t2 and time t5, the transmitter is configured to wait for and / or receive a response from the receiver.

[0067] Between the time t2 which corresponds to the end of the reception of the protocol data unit of rank N and a later time t3, the receiver is for example deactivated to observe the adjustment duration (Delay to Ack).

[0068] Between time t3 and a later time t4, before a time t5, the receiver is reactivated and it returns an acknowledgment (Ack). However, in the example in [Fig.3], the transmitter, waiting for the receiver's response, does not receive this acknowledgment (No reception).

[0069] Between times t4 and t5, a buffer period is provided to compensate for, for example, differences in clock frequencies between transmitter and receiver.

[0070] The example of [Fig.3] between the successive instants t0 and t5 corresponds to the sequence of the steps of [Fig.2], 202, 204, 210, 212, 214 and 218. The example of [Fig.3] between the successive instants t5 and t9 corresponds to the sequence of the steps of [Fig.2], 202, 204, 206, 207, 209, 214 and 218.

[0071] The interval between times t0 and t5 corresponds to a first attempt at data transmission. Since the transmitter does not receive the acknowledgment, it will try to send the same protocol data unit again (Re-transmit#1).

[0072] For this, at time t5 and until a later time t6, the header (Header SeqNr N) of the protocol data unit (PDU payload) of rank N is returned by the module in transmitter mode to the module in receiver mode. After reading and identifying rank N of the header by the receiver, the receiver or part of its circuits are deactivated until a time t7 (remaining receive time) and, after having respected the adjustment duration (Delay to Ack) between time t7 and a time t8, a new acknowledgment of receipt is sent by the reactivated receiver between time t8 and a time t9.

[0073] Since the protocol data unit of rank N has already been received during the first interval (transmit#1), the receiver, which is deactivated during the resending of the already received data unit, does not have to use energy to receive a protocol data unit already received.

[0074] At time t8, the receiver is reactivated so that a new acknowledgment of receipt (Ack) is retransmitted by the receiver and received this time by the transmitter. The reception of the acknowledgment of receipt by the transmitter results, after time t9, in the sending of the header and a protocol data unit of the next rank N+1 (Transmit packet #2).

[0075] Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these various embodiments and variants could be combined, and other variants will appear to those skilled in the art. In particular, the protocol may provide for a systematic repetition of sendings of protocol data units of the same rank. In this case, the disclosed method makes it possible, for each repetition of sending of the same protocol data unit, to deactivate the receiver.

[0076] The example of [Fig.3] graphically presents the sending and receiving of protocol data units or the sending and receiving of acknowledgments as simultaneous, however, the person skilled in the art will understand that there is a certain time lag. in the time between transmission and reception.

[0077] Finally, the practical implementation of the embodiments and variants described is within the reach of the person skilled in the art from the functional indications given above. In particular, as regards the implementation of the adjustment duration, this can be optional or adjusted according to the clock technologies used.

Claims

Claims

1. Method for controlling a receiver (102) for radiofrequency communications in which intervals between the reception of a header (Header SeqNr N) of a data packet and an acknowledgment sent by the receiver are constant, method in which, once a packet has been correctly received, circuits of the receiver are put on standby for a duration corresponding to said interval after each reception of a header of the same rank as that of the correctly received packet.

2. Receiver (102) for radiofrequency communications in which intervals between the reception of a header (Header SeqNr N) of a data packet and an acknowledgment sent by the receiver are constant, receiver in which, once a packet has been correctly received, circuits are put on standby for a duration corresponding to said interval after each reception of a header of the same rank as that of the correctly received packet.

3. Method according to claim 1, or receiver according to claim 2, in which after each reception of a header of rank different from that of the correctly received packet, said circuits of the receiver remain active for at least part of the corresponding interval.

4. A method according to claim 1 or 3, or a receiver according to claim 2 or 3, wherein the data packet of each of the intervals is arranged in a protocol data unit (payload PDU).

5. A method or receiver according to claim 4, wherein the intervals have a size greater than a predetermined maximum size of protocol data units.

6. A method or receiver according to claim 5, wherein each of the intervals comprises a clock adjustment time (Delay to Ack) between the protocol data unit and the acknowledgment sent by the receiver.

7. A method or receiver according to claim 6, wherein during the adjustment period, said receiver circuits are put into standby.

8. A method according to any one of claims 1 or 3 to 7, or a receiver according to any one of claims 2 to 7, wherein said receiver circuitry is active for sending the acknowledgment.

9. Radio frequency communication system comprising: - a first communication module configured to transmit data packets having a header indicating their respective rank and, - a second communication module configured to implement the method according to any one of claims 1 or 3 to 8.

10. The system of claim 9, wherein the first module is also configured to implement the method of any one of claims 1 or 3 to 8.

11. The system of claim 10, wherein the first module and the second module are identical.

12. System according to claim 10 or 11, wherein the first and / or the second modules comprise a radio frequency signal transmission block (132, 124) and a radio frequency signal reception block (122, 134).

13. System according to claim 12, in which the signal transmission block (132, 124) and the reception block, of the first and / or the second module, are connected to a respective antenna (172, 174) via a switch connecting the antenna sometimes to the transmission block, sometimes to the reception block.

14. The system of any one of claims 9 to 13, wherein the first and / or second modules comprise a data buffer storage module (142, 144) configured to store an acknowledgment and / or data packets.

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