Adaptive error avoidance method to improve retransmission reliability of time-slotted communication links

Abstract

The present disclosure relates to an adaptive error avoidance method to improve reliability of retransmission of time-slotted communication links. A network node device of a communication network, comprising: a physical (PHY) layer circuit configured to transmit and receive data packets via the communication network; and a processing circuit connected to the PHY layer circuit. The processing circuit is configured to encode a data packet for transmission according to a first communication protocol to a second network node during a designated communication time slot, initiate a retransmission of the data packet when the second network node does not respond during a designated acknowledgement time slot, and encode the data packet according to a second communication protocol for transmission to the second network node for a last of a limited number of retry attempts, wherein the time of transmission of the data packet formatted in the third communication protocol extends into the designated acknowledgement time slot.

Description

Background Technology

[0001] A communication network transmits data between its nodes. Communication between any two network nodes can use one or more communication channels. Communication channels may be unreliable, and the content of transmitted messages may be corrupted. Summary of the Invention

[0002] This document generally relates to communication networks, and more particularly to techniques for improving the reliability of retransmitted packets using error avoidance mechanisms without affecting time slot duration or requiring time slot reallocation. An example of a method for operating a communication network includes: sending a data packet from a first network node to a second network node during a specified communication time slot, wherein the data packet is formatted according to a first communication protocol; retransmitting the data packet by the first network node when the second network node does not respond during a specified acknowledgment time slot; and retransmitting the data packet for a final retry attempt in a finite number of retries to send the data packet, wherein the first network node retransmits the data packet for the final retry attempt according to a second communication protocol that extends the time for sending the data packet into the specified acknowledgment time slot.

[0003] An example of a network node device in a communication network includes: physical (PHY) layer circuitry configured to transmit and receive data packets via the communication network; and processing circuitry connected to the PHY layer circuitry. The processing circuitry is configured to: encode a data packet for transmission according to a first communication protocol to be transmitted to a second network node during a specified communication time slot; initiate a retransmission of the data packet if the second network node does not respond during a specified acknowledgment time slot; and encode the data packet according to a second communication protocol to be transmitted to the second network node in the last retry attempt out of a finite number of retries, wherein the transmission of the data packet formatted according to the third communication protocol extends into the specified acknowledgment time slot.

[0004] Another example of a network node device in a communication network includes: PHY layer circuitry and processing circuitry connected to the PHY layer. The processing circuitry is configured to: encode an acknowledgment message for transmission when no error is detected in a received data packet; detect that the received data packet contains an error; and decode subsequently received data packets according to a second communication protocol when a first received data packet contains an error.

[0005] This section is intended to provide an overview of the subject matter of this patent application. It is not intended to provide an exclusive or exhaustive interpretation of the invention. Detailed descriptions are included to provide further information regarding this patent application. Attached Figure Description

[0006] In accompanying drawings that are not necessarily drawn to scale, the same numbers may describe similar parts in different views. Similar numbers with different letter suffixes may represent different instances of similar components. The accompanying drawings illustrate, by way of example and not limitation, the various embodiments discussed in this document.

[0007] Figure 1 It is a diagram of a communication network.

[0008] Figure 2 This is a functional block diagram of a network node.

[0009] Figure 3 This is a diagram illustrating the time slots allocated to the communication network.

[0010] Figure 4 This is a timing diagram showing an example of a time slot.

[0011] Figure 5 This is a flowchart illustrating an example of operating a communication network.

[0012] Figure 6-8 This is a diagram illustrating the sending of data packets using different communication protocols. Detailed Implementation

[0013] Figure 1 This is a conceptual diagram of a communication network 100. The communication network 100 includes multiple network nodes 102 and a network manager node 104. Figure 1 In the example, the communication link between network nodes 102 is a wireless link, and any network node 102 can communicate data with any other network node 102 within range. In a variant, the communication link between network nodes 102 is a wired link.

[0014] Figure 2 This is a functional block diagram of network node 102. Network node 102 may include physical layer (PHY) circuitry 206 for transmitting and receiving radio frequency (RF) signals to and from one or more network nodes using one or more antennas 208. PHY circuitry 206 may include circuitry for modulation / demodulation, up-conversion / down-conversion, filtering, amplification, etc. Network node 102 may also include media access control (MAC) layer circuitry 210 for controlling access to the wireless medium and configuring frames or packets for communication over the wireless medium. Network node 102 may also include processing circuitry 212 and a memory 214, arranged to configure the various elements of the network node to perform the operations described herein. Memory 214 may be used to store information for configuring processing circuitry 212 to perform operations.

[0015] Although network node 102 is shown as having multiple individual functional elements, one or more functional elements can be combined and implemented through software configuration of the combination of elements, such as processing elements including a digital signal processor (DSP) and / or other hardware elements of processing circuitry 212. For example, some elements may include one or more microprocessors, DSPs, application-specific integrated circuits (ASICs), radio frequency integrated circuits (RFICs), and combinations of various hardware and logic circuits for performing at least the functions described herein. In some embodiments, a functional element may refer to one or more processes operating on one or more processing elements.

[0016] Embodiments may be implemented as one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage medium that can be read and executed by at least one processor to perform the operations described herein. The computer-readable storage medium may include any non-transitory mechanism for storing information in a machine-readable (e.g., computer-readable) form. For example, a computer-readable storage medium may include read-only memory (ROM), random access memory (RAM), disk storage media, optical storage media, flash memory devices, and other storage devices and media. In these embodiments, one or more processors may be configured with instructions for performing the operations described herein.

[0017] Figure 3 This is for communication networks (e.g.) Figure 1 A diagram illustrating the time slots allocated in the communication network 100. Time-slot communication links quantize time into discrete time periods called time slots, during which node devices send or receive data packets. Data packets are transmitted according to a specified communication protocol, which can define one or more of the following: the format of information in the data packet, the format of the preamble and header required before the data payload, the bit rate of the transmitted data packet, the delay between data transmissions, etc. Typically, one network node will transmit during a time slot, and one or more network nodes will receive transmissions using one or more communication channels. During the next time slot, different nodes and different communication channels will be active.

[0018] Time Division Duplex (TDD) refers to a system that separates the uplink and downlink by allocating different periods within time slots or time slot frames. Ensuring that node devices can only transmit and receive at specific times reduces the likelihood of "collisions" between synchronous devices and multiple devices attempting to transmit simultaneously. In time slot communication, a time slot is a time period allocated to a group of devices for transmitting or receiving data. Time Slot Channel Switching (TSCH) combines time slot communication with synchronization channel switching.

[0019] When transmitting data over a communication channel, there is often a trade-off between raw data throughput and reliability (i.e., the link's resilience to interference and noise). Communication channels can become unreliable, and the transmitted message content may be corrupted. A single weak communication link can affect one or more aspects of the system's timing, throughput, and latency. To improve communication reliability, receiving network nodes (receivers) typically acknowledge packets by sending acknowledgment messages (ACKs) back to sending network nodes (transmitters).

[0020] Figure 4 This is a timing diagram illustrating an example of a time slot. During this time slot, the transmitting node sends packet 420, the receiving node receives packet 422, the receiving node sends ACK (acknowledgment of receipt) 424, and the transmitting node receives ACK message 426. The data packet includes the preamble and header portions required by the protocol, as well as a payload portion containing the useful information to be transmitted.

[0021] If the communication channel is unreliable, data packet messages will not be decoded correctly and will contain errors. Receiver nodes can use error detection circuits, such as cyclic redundancy code (CRC) circuits, to detect errors. If the receiver node detects an error, it will not send an ACK back to the transmitter node. After a period without receiving an ACK, the transmitter node will attempt to send the data packet again. If no ACK is received during the retry attempt, the transmitter node will retry sending the packet a limited number of times and eventually discard the packet (no retry and transmission failure).

[0022] In a time-slot system, a time slot can be roughly divided into the following regions:

[0023] Gap time = Pre-transmission + PKT header + Packet + Turnaround + ACK header

[0024] Header + ACK + gap post-processing.

[0025] in:

[0026] - Pre-transmission may include some processing, transceiver ramp-up and / or protection time.

[0027] The -Pk header is the time spent transmitting the preamble, start frame delimiter (SFD), and / or header (if any).

[0028] - Package refers to the actual effective payload time.

[0029] - The turnaround may require some processing at the receiver end to verify the content of the received data, as well as the transceiver turnaround.

[0030] The -ACK header is the time taken to transmit the preamble, SFD, and / or header (if any).

[0031] -ACK refers to the time taken to send an acknowledgment.

[0032] - Gap post-processing refers to the time required for ACK processing, transceiver status control, and other tasks.

[0033] As can be seen from this breakdown of gap time allocation, the gap time (and therefore the effective channel throughput) depends on the transceiver's effective data rate and the size of the payload. A long payload and a low transceiver data rate increase the time required to send the header and payload (packet and ACK), while a short payload has the opposite effect with a high transceiver data rate.

[0034] However, the final effective data rate does not entirely depend on the transceiver's payload size or data rate, because other stages (such as pre-transmission, turnaround, gap post-processing, etc.) do not necessarily change with the transceiver's data rate. Doubling the effective packet and ACK time by changing the PHY mode, coding rate, or transceiver payload size will require more time for these stages, resulting in an increase in slot duration. When link quality degrades, systems using adaptive PHY rates tend to choose different modulation schemes with higher coding rates to improve reliability, but this increases the time spent sending packets and ACKs, leading to longer slots and lower effective throughput.

[0035] An ACK message helps the transmitting node determine whether a data packet has been correctly received by the receiving node. If the data packet has not been correctly received, no ACK is returned, and the transmitting node can attempt to retransmit the packet. When the transmitter needs to retransmit a data packet, the "packet" transmission phase can be extended beyond its normally allocated time, utilizing the time normally allocated to radio turnaround and ACK reception.

[0036] These "un-ACKed" slots will have longer packet phase and will be unidirectional because the receiver node does not return anything during the slot. If the slot is the last retry attempt in a slot frame or measurement interval, the ACK has no effect. The data will be discarded anyway, and the transmitter node does not need to know if the data was received correctly. By switching to a different mode that may be more resilient to errors (at the cost of lower data rates and packet time), the time spent on the ACK for the last retry attempt can be better utilized to ensure a higher chance of success.

[0037] Figure 5 It is to operate a communication network (e.g.) Figure 1The flowchart illustrates an example of a communication network. In 505, the transmitter node's processing circuitry encodes data packets for transmission to one or more receiver nodes during a specified communication time slot. The data packets are formatted according to a first communication protocol that defines one or both of the amount of data in the packet and the rate at which data is transmitted. The receiver node decodes the packets. If the receiver node does not detect an error, its processing circuitry encodes an ACK message to send a message that the data packet has been received to the transmitter node. If an error is detected, the receiver node does not send an ACK message.

[0038] If the transmitter node does not receive an ACK from the receiver node within the specified acknowledgment slot in response to the transmission, then in block 510, the transmitter node's processing circuitry begins retransmitting the data packet. If the receiver node does not respond with an ACK message, the processing circuitry initiates a limited number of retries to retransmit the data packet.

[0039] In box 515, the transmitter node initiates a retransmission of the data packet for a final retry attempt. The transmitter node's processing circuitry encodes the packet from the previous retry attempt according to a different communication protocol that is more robust to errors. The second communication protocol uses one or more methods to reduce or recover from errors, at the cost of a lower data rate and a longer packet transmission time. The final retry attempt extends the packet transmission time by the specified acknowledgment time of the time slot. If no error is detected in the packet, the receiver node decodes the final retry attempt according to the second communication protocol. Regardless of whether the packet was successfully received, the receiver node does not send an ACK message.

[0040] Figure 6 This is a diagram illustrating the transmission of data packets according to non-extended communication protocol format 630 and extended communication protocol format 632. Non-extended protocol format 630 shows the time 634 is reserved in the time slot for the ACK message. Extended communication protocol format 632 shows the time when the payload portion of data packet 636 is transmitted, extending into the time 634 reserved in the time slot for the ACK message. Returning ACK messages is suppressed in extended communication protocol format 632.

[0041] The transmission time for the payload portion of data packet 636 can be extended because the payload size is increased to include measures for recovering from data errors during transmission, such as error avoidance coding. Examples of error avoidance coding are error correcting codes (ECC) and forward error correction (FEC).

[0042] Error-correcting codes (ECCs) are algorithms used to encode data bits so that errors can be detected (and potentially corrected) if a received data packet is corrupted. ECC techniques typically involve appending redundant information to the original data payload. The receiver node decodes the ECC and uses it to detect and correct errors in the original payload. Because ECCs are non-zero in size, while these codes offer better reliability and resilience, the overhead associated with them is also significant. Figure 6 In this context, the data payload may include ECC. This results in a larger payload, extending into the 634-minute time slot reserved for the ACK message.

[0043] The time required to transmit the payload portion of data packet 636 can also be extended because one or both of the packet header and payload are transmitted at a slower rate than in non-extended protocols. The processing circuitry of the transmitter network node can change the PHY mode to alter the data rate.

[0044] Figure 7 This is an illustration of sending data packets according to the normal communication protocol format 730 and the extended communication protocol format 732 used for the last retry attempt. The ACK message is suppressed and the data packet is sent at a slower rate (e.g., half the rate of the normal protocol), resulting in a data payload that extends into the time slot reserved for the ACK message 734. Figure 8 This is an illustration of another example of sending data packets according to the normal communication protocol format 830 and the extended communication protocol format 822. In this example, the communication channel is already operating at half the data rate (e.g., to avoid errors), and the data rate is further slowed down to one-third of the data rate.

[0045] like Figure 6-8 As shown, if the time taken for a new packet is less than the time initially allocated to turnaround and ACK, this adaptive method can be used on the same network without affecting the overall size of the time slots.

[0046] Gap time = Pre-transmission + PKT header + Packet + Gap post-processing.

[0047] The interval time will remain constant under the following conditions:

[0048] (Avoid incorrect packets) <= (Packet + Turnover + ACK header + ACK).

[0049] The time taken for the extended last retry packet must be within the allocated gap time limit, and the receiver node needs to be able to detect the transmission pattern (or know it in advance) so that it can receive it correctly. In some examples, the header portion of the extended communication protocol formatted packet indicates that the packet uses the extended communication protocol. This allows the receiver node to receive and decode these packets using the extended communication protocol without any prior notice or entry into transmission scheduling. In some examples, the receiver node's processing circuitry counts the number of retry attempts, which is a predetermined number of attempts. The number of retry attempts can be transmitted between nodes (e.g., by...). Figure 1 (Network Manager node 104 in the example). When the receiver node's processing circuitry detects that the next attempt will be the last retry, the receiver node can switch to an extended communication protocol. These examples are just a few of the many ways a receiver can be used to receive packets in both formats.

[0050] Several examples of the systems, devices, and methods described provide techniques for improving the reliability of retransmitted packets using stronger error avoidance mechanisms without affecting time slot duration or requiring time slot reallocation. Any error avoidance mechanism can be used, as long as the overhead for activating the error avoidance mechanism is within the allocated time slot time for communication.

[0051] Additional notes and aspects

[0052] The first aspect (Aspect 1) includes a subject (e.g., a network node device of a communication network), comprising physical (PHY) layer circuitry configured to transmit and receive data packets via the communication network; and processing circuitry connected to the PHY layer circuitry. The processing circuitry is configured to encode data packets intended for transmission according to a first communication protocol for transmission to a second network node during a specified communication time slot; to initiate a retransmission of the data packets if the second network node does not respond during a specified acknowledgment time slot; and to encode the data packets according to a second communication protocol for transmission to the second network node in a final retry attempt out of a finite number of retries, wherein the time for transmitting the data packets formatted according to the third communication protocol extends into the specified acknowledgment time slot.

[0053] In aspect 2, the subject matter of aspect 1 may optionally include: the processing circuitry is configured to change the PHY mode to reduce the data rate of the data packets.

[0054] In aspect 3, one or both of aspects 1 and 2 may optionally include the following: the processing circuitry is configured to reformat the data packet in the last retry attempt to increase data redundancy in the data packet from the first communication protocol.

[0055] In aspect 4, the subject matter of one or any combination of aspects 1-3 may optionally include: the processing circuitry being configured to reformat the data packet in the last retry attempt to increase the payload of the data packet.

[0056] In aspect 5, the subject matter of one or any combination of aspects 1-4 may optionally include: the processing circuitry being configured to reformat the data packet in the last retry attempt to increase the number of copies of data in the payload of the data packet, and to protect each copy with error avoidance coding.

[0057] In aspect 6, the subject matter of one or any combination of aspects 1-5 may optionally include: the processing circuitry being configured to format the header of the data packet in the last retry attempt to indicate that the data packet uses a second communication protocol.

[0058] Aspect 7 includes a subject (e.g., a method of operating a communication network), or may optionally be combined with one or any combination of aspects 1-6 to include a subject comprising: sending a data packet from a first network node of the communication network to a second network node during a specified communication time slot, wherein the data packet is formatted according to a first communication protocol; retransmitting the data packet by the first network node when the second network node does not respond during a specified acknowledgment time slot; and retransmitting the data packet for the last retry attempt in a finite number of retries to send the data packet, wherein the first network node retransmits the data packet for the last retry attempt according to a second communication protocol that extends the time for sending the data packet into the specified acknowledgment time slot.

[0059] In aspect 8, the subject matter of aspect 7 may optionally include: sending at least a portion of the data packet at a lower rate than the first protocol.

[0060] In aspect 9, one or both of aspects 7 and 8 may optionally include the following: the first network node reformatting the data packet to increase the payload of the data packet.

[0061] In aspect 10, the subject matter of one or any combination of aspects 7-9 may optionally include: the first network node reformatting the data packet to increase data redundancy in the data packet relative to the first communication protocol.

[0062] In aspect 11, the subject matter of one or any combination of aspects 7-10 may optionally include: the first network node formatting the header of the data packet to indicate that the data packet uses the second communication protocol.

[0063] In aspect 12, the subject matter of one or any combination of aspects 7-11 may optionally include: the second network node determining that the next retry attempt is the last retry attempt in the finite number of retry attempts, and changing to the second communication protocol in response to the determination.

[0064] Aspect 13 includes a subject matter (e.g., a network node device for a communication network), or may optionally be combined with one or any combination of aspects 1-12 to include a subject matter comprising: physical PHY layer circuitry configured to transmit and receive data packets via a communication network, and processing circuitry connected to the PHY layer circuitry. The processing circuitry is configured to decode received data packets according to a first communication protocol; encode an acknowledgment message for transmission when no error is detected in the received data packets; detect one or more received data packets containing errors; and decode subsequently received data packets according to a second communication protocol when the one or more received data packets contain errors.

[0065] In aspect 14, the subject matter of aspect 13 may optionally include: the processing circuitry being configured to decode a header in a subsequently received data packet, the header indicating that the subsequently received data packet will be decoded in accordance with a second communication protocol.

[0066] In aspect 15, one or both of aspects 13 and 14 may optionally include the following: the processing circuitry is configured to: count retry attempts of sending a first data packet in one or more received data packets; and when the count of retry attempts reaches a predetermined number or retry attempts, change to decoding subsequently received data packets according to a second communication protocol.

[0067] Aspect 16 includes a subject (or may optionally be combined with one or any combination of aspects 1-15 to include such a subject), such as a computer-readable storage medium containing instructions that, when executed by processing circuitry of a network node device of a communication network, cause the processing circuitry to perform actions including: encoding a data packet for transmission to a second network node device during a specified communication time slot, wherein the data packet is formatted according to a first communication protocol; initiating a retransmission of the data packet when the second network node device does not respond during a specified acknowledgment time slot; and encoding the data packet according to a second communication protocol for transmission of the last retry attempt in a finite number of retries for transmitting the data packet, wherein encoding the data packet of the last retry attempt extends the time for transmitting the data packet into the specified acknowledgment time slot.

[0068] In aspect 17, the subject matter of aspect 16 may optionally include: instructions to cause the processing circuitry to perform actions, the actions including: encoding at least a portion of the data packet at a rate lower than that of the first communication protocol according to the second communication protocol.

[0069] In aspect 18, one or both of aspects 16 and 17 may optionally include: causing the processing circuitry to execute instructions including actions such as reformatting the data packet according to the second communication protocol to increase the payload of the data packet from the first communication protocol.

[0070] In aspect 19, the subject matter of one or any combination of aspects 16-18 may optionally include: instructions to cause the processing circuitry to perform actions, the actions including encoding the data packet according to the second communication protocol to increase data redundancy in the data packet relative to the first communication protocol.

[0071] In aspect 20, the subject matter of one or any combination of aspects 16-19 may optionally include: causing the processing circuitry to execute instructions including encoding the header portion of the data packet to indicate that the data packet is using the second communication protocol.

[0072] These non-limiting aspects can be combined in any arrangement or combination. The above detailed description includes reference to the accompanying drawings, which form a part of the detailed description. The drawings illustrate specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” All publications, patents, and patent documents mentioned in this document are incorporated herein by reference in their entirety, as if individually incorporated by reference. In the event of any inconsistency between the usage of this document and the documents merged by reference, the usage in the merged reference shall be considered supplementary to this document; in the case of irreconcilable inconsistencies, the usage in this document shall prevail.

[0073] In this document, the terms "a" or "an," as is common in patent documents, include one or more, independent of any other instance or use of "at least one" or "one or more," and unless otherwise stated, "A or B" includes "A but not B," "B but not A," and "A and B." In the appended claims, the terms "comprising" and "wherein" are used as the corresponding terms "including" and "in." Furthermore, in the following claims, the terms "comprising" and "including" are open-ended, meaning that a system, apparatus, article, or process that includes elements in addition to those listed after the term in the claim is still considered to fall within the scope of that claim. Additionally, in the following claims, the terms "first," "second," and "third," etc., are used merely as labels and are not intended to impose numerical requirements on their objects. The examples of methods described herein may be implemented at least in part by a machine or computer.

[0074] The above description is intended to be illustrative and not restrictive. For example, the examples (or one or more aspects thereof) described above may be used in combination with each other. Other embodiments may be used, for example, as would be employed by one of ordinary skill in the art upon review of the above description. The abstract is provided in accordance with 37 C. FR § 1.72(b) to enable the reader to quickly determine the nature of the technical disclosure. It is understood that this application is not intended to interpret or limit the scope or meaning of the claims. Furthermore, in the detailed description above, various features may be grouped together to simplify this disclosure. This should not be construed as meaning that any unclaimed disclosed feature is necessary for any claim. Rather, the subject matter of the invention may not include all features of a particular disclosed embodiment. Therefore, the following claims are hereby incorporated into the detailed specification, each claim being an independent embodiment. The scope of the invention should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. A network node device for a communication network, the network node device comprising: The physical (PHY) layer circuitry is configured to send and receive data packets via a communication network; and The processing circuitry, connected to the PHY layer circuitry, is configured to: Encode the data packets intended for transmission according to the first communication protocol so that they can be transmitted to the second network node during a specified communication time slot; If the second network node does not respond during the specified acknowledgment time slot, it initiates a retransmission of the data packet; and The data packet is encoded according to a second communication protocol and sent to the second network node for the last retry attempt in a limited number of retries, wherein the time for sending the data packet formatted according to the second communication protocol extends into the specified acknowledgment slot of the last retry attempt.

2. The network node device of claim 1, wherein the processing circuitry is configured to change the PHY mode to reduce the data rate of the data packets.

3. The network node device of claim 1, wherein the processing circuitry is configured to reformat the data packet in the last retry attempt to increase data redundancy in the data packet from the first communication protocol.

4. The network node device of claim 1, wherein the processing circuitry is configured to reformat the data packet in the final retry attempt to increase the payload of the data packet.

5. The network node device of claim 1, wherein the processing circuitry is configured to reformat the data packet in the last retry attempt to increase the number of copies of data in the payload of the data packet and to protect each copy with error avoidance coding.

6. The network node device of claim 1, wherein the processing circuitry is configured to format the header of the data packet in the last retry attempt to indicate that the data packet uses a second communication protocol.

7. A method for operating a communication network, the method comprising: During a specified communication time slot, data packets are sent from a first network node to a second network node in a communication network, wherein the data packets are formatted according to a first communication protocol; If the second network node does not respond during the specified acknowledgment time slot, the first network node will resend the data packet. and The data packet is retransmitted for the last retry in a limited number of retries to send the data packet, wherein the first network node retransmits the data packet for the last retry according to a second communication protocol that extends the time for sending the data packet to a specified acknowledgment slot of the last retry.

8. The method of claim 7, wherein retransmission according to the second communication protocol includes transmitting at least a portion of the data packet at a lower rate than the first communication protocol.

9. The method of claim 7, wherein the data packet is retransmitted according to the second communication protocol, including reformatting the data packet by the first network node to increase the payload of the data packet.

10. The method of claim 7, wherein retransmission according to the second communication protocol includes the first network node reformatting the data packet to increase data redundancy in the data packet relative to the first communication protocol.

11. The method of claim 7, wherein retransmission according to the second communication protocol includes the first network node formatting the header of the data packet to indicate that the data packet uses the second communication protocol.

12. The method of claim 7, further comprising the second network node determining that the next retry attempt is the last retry attempt in the finite number of retry attempts, and changing to the second communication protocol in response to the determination.

13. A network node device for a communication network, the network node device comprising: The physical PHY layer circuitry is configured to send and receive data packets via a communication network. and The processing circuitry, connected to the PHY layer circuitry, is configured to: During the specified communication time slot, the received data packets are decoded according to the first communication protocol, and a limited number of retries are performed; During the specified acknowledgment time slot, if no error is detected in the received data packet, the acknowledgment message to be sent is encoded. Detect one or more errors in the received data packets; and When one or more received data packets contain errors, the data packets subsequently received in the last retry attempt are decoded according to the second communication protocol, wherein the time for receiving the subsequently received data packets extends into a specified acknowledgment slot.

14. The network node device of claim 13, wherein the processing circuitry is configured to decode a header in a subsequently received data packet, the header indicating that the subsequently received data packet will be decoded according to a second communication protocol.

15. The network node device of claim 13, wherein the processing circuitry is configured to: Count the retries for sending the first data packet in the one or more received data packets; and When the count of retry attempts reaches a predetermined number of retry attempts, the system changes to decode subsequently received data packets according to the second communication protocol.

16. A non-transitory computer-readable storage medium containing instructions that, when executed by processing circuitry of a network node device of a communication network, cause the processing circuitry to perform actions including: Encode data packets intended to be sent to a second network node device during a specified communication time slot, wherein the data packets are formatted according to a first communication protocol; If the second network node device does not respond during the specified acknowledgment time slot, it initiates a retransmission of the data packet; and The data packet is encoded according to a second communication protocol for sending the last retry attempt in a finite number of retries for sending the data packet, wherein the encoding of the data packet for the last retry attempt extends the time for sending the data packet to the specified acknowledgment slot of the last retry attempt.

17. The non-transitory computer-readable storage medium of claim 16, further comprising instructions for causing the processing circuitry to perform an action, the action comprising: At least a portion of the data packet is encoded according to the second communication protocol at a rate lower than that of the first communication protocol.

18. The non-transitory computer-readable storage medium of claim 16, further comprising instructions for causing the processing circuitry to perform actions including reformatting the data packet according to the second communication protocol to increase the payload of the data packet from the first communication protocol.

19. The non-transitory computer-readable storage medium of claim 16, further comprising instructions for causing the processing circuitry to perform actions, the actions including encoding the data packet according to the second communication protocol to increase data redundancy in the data packet relative to the first communication protocol.

20. The non-transitory computer-readable storage medium of claim 16, further comprising causing the processing circuitry to execute instructions including encoding a header portion of the data packet to indicate that the data packet is using the second communication protocol.

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