Technology for reducing transmission failures in time-slot channel-hopping networks

Abstract

A first node in a TSCH network may receive a message initiation packet from a second node on the TSCH network. Based on information in the message initiation packet, the first node may determine a transmission time of a message content packet associated with the message initiation packet. The first node may generate or modify a node-specific transmission delay that indicates a backoff associated with the second node. The node-specific transmission delay may indicate a number of backoff time slots that the first node delays initiating a transmission with the second node. If the first node receives additional packets destined for the second node during the node-specific transmission delay, the first node may queue the additional packets until the node-specific transmission delay is completed.

Description

Technical Field

[0001] The present disclosure generally relates to the field of message transmission protocols in computer networks, and more specifically, to reducing transmission failures related to message transmission.

Background Art

[0002] A computer network may include one or more computing devices, i.e., nodes, that communicate with other nodes within the computer network. In some cases, a computer network may implement a time-slotted channel hopping (“TSCH”) protocol. In some cases, a computer network implementing the TSCH protocol (“TSCH network”) may include multiple nodes that transmit and receive messages, such as messages containing packets. Nodes included in a TSCH network may transmit and receive messages with neighboring nodes within the network, and such transmissions occur within a specific time slot on a specific channel of the TSCH protocol. In some cases, a TSCH network may include one or more devices operating on a limited power source (such as a battery), one or more devices operating on a stable power source (such as an electrical connection to grid power), or devices using a combination of a limited power source or a stable power source.

[0003] In some cases, the first node may initiate a transmission to a second node in the TSCH network. However, if the second node is already engaged in a transmission with an additional node, the transmission from the first node may fail. For example, the second node may not respond to the transmission from the first node, or the transmission from the first node may be interrupted. In some cases, a failed transmission can lead to inefficient operation of nodes in the TSCH network. For example, the first node may inefficiently use a time slot by attempting to transmit to the second node while the second node is already engaged in a transmission. In addition, the first node may wait for a certain period before attempting to transmit to the second node again, resulting in further inefficiencies associated with the waiting period. In some cases, a battery-powered node may consume energy to attempt a transmission, such as by applying battery power to enhance antenna functionality. If the transmission fails, the battery-powered node may have inefficiently used battery power without completing the transmission attempt. To improve the efficient operation of a TSCH network, it is desirable to reduce transmission failures between nodes within the TSCH network. [Overview of the Initiative]

[0004] According to a particular embodiment, a computer network node in a TSCH network may be configured to receive message initiation packets from additional nodes in the TSCH network. Based on the message initiation packets, the computer network node may determine the number of backoff time slots during which the additional node will transmit message content packets. The message content packets may be associated with the message initiation packets. The computer network node may correct node-specific transmission delays associated with the additional node. The node-specific transmission delays may indicate that the additional node will not be able to receive transmissions during the number of backoff time slots. The computer network node may receive additional message content packets that have a destination for the additional node. Based on the node-specific transmission delays, the computer network node may queue additional message packets for transmission after the number of backoff time slots.

[0005] In some embodiments, a first node may receive a message initiation packet from a second node. Based on the message initiation packet, the first node may determine the transmission time of the message content packet associated with the message initiation packet. The first node may correct a node-specific transmission delay associated with the second node. The node-specific transmission delay may indicate the number of backoff time slots that the first node will delay in initiating transmission to the second node. The first node may determine additional message content packets that have a destination for the second node. Based on the node-specific transmission delay, the first node may queue additional message packets for transmission to the second node after the node-specific transmission delay.

[0006] These exemplary embodiments are mentioned not to limit or define the disclosure, but to provide examples that aid in understanding the disclosure. Additional embodiments are discussed in the detailed description, where further explanation is provided.

[0007] The features, embodiments, and advantages of this disclosure will be better understood by referring to the accompanying drawings and reading the following detailed description. [Brief explanation of the drawing]

[0008] [Figure 1A] Figure 1A (collectively referred to as Figure 1 in this specification, together with Figure 1B) shows an example of a TSCH network including multiple nodes having routing relationships or transmission distances, according to a particular embodiment. [Figure 1B] Figure 1B (collectively referred to as Figure 1 in this specification, together with Figure 1A) shows an example of a TSCH network including multiple nodes having routing relationships or transmission distances, according to a particular embodiment. [Figure 2] This flowchart shows an example of a process for reducing transmission failures between nodes in a TSCH network, according to a specific embodiment. [Figure 3] This flowchart shows an example of a process for calculating the backoff value of nodes in a TSCH network according to a specific embodiment. [Figure 4] This figure shows an example of a transmission environment in which a signal can be transmitted within a TSCH network according to a specific embodiment. [Figure 5] This figure shows an example of a transmission environment in which node-specific transmission delays can be determined for nodes within a TSCH network, according to a specific embodiment. [Figure 6] This figure shows an example of a computing environment that can determine the node-specific transmission delay of nodes in a TSCH network, according to a specific embodiment. [Modes for carrying out the invention]

[0009] As described above, the efficient transmission of messages within a TSCH network can be improved by reducing transmission failures between nodes within the TSCH network. Certain embodiments described herein provide techniques for reducing transmission failures related to receiving nodes that are not ready to receive a message, such as receiving nodes that are already involved in additional transmissions to another node. For example, a sending node may initiate the transmission of a message to another node in the TSCH network. Part of the message may be broadcast to multiple nodes in the TSCH network, such as a message header packet ("header," "header packet") that is broadcast to multiple nodes within the communication range of the sending node. Nodes receiving the header packet may include nodes that are not recipients of the message content and may determine, based on the information contained in the header, that the sending node will be involved in the transmission. For example, non-receiving nodes (e.g., nodes that are not recipients of the message content) may determine, based on the communication mode and message size indicated by the header, that the sending node is involved in the transmission for a certain number of time slots. In addition, non-receiving nodes may determine a node-specific transmission delay associated with the sending node. During the node-specific transmission delay, non-receiving nodes may avoid attempts at additional transmissions with the sending node. For example, a message directed to a sending node may be queued for subsequent transmission after a node-specific transmission delay has been completed. In some cases, determining a node-specific transmission delay for a particular node can reduce the number of transmission attempts to that node while that node is already involved in a transmission, thereby reducing transmission failures with that node. In addition, avoiding transmission attempts with a particular node during a node-specific transmission delay can improve the utilization of network resources on the TSCH network by freeing up communication channels for use by additional nodes for additional transmissions and reducing power consumption associated with failed transmission attempts.

[0010] In some embodiments, a first node on a TSCH network may receive a message initiation packet, such as a header packet or a mode switching packet, from a second node on the TSCH network. For example, the second node may broadcast a message initiation packet on the TSCH network to all nodes within its communication range. Based on the information in the message initiation packet, the first node may determine the transmission time of the message content packet associated with the message initiation packet. For example, the message initiation packet may indicate one or more of the size of the message content packet, the communication mode of the message content packet, or any other appropriate information describing the transmission of the message content packet. The transmission time may indicate the number of time slots or the communication channel reserved for the transmission of the message content packet. The first node may generate or modify a node-specific transmission delay that indicates a backoff associated with the second node. For example, the node-specific transmission delay may indicate the number of backoff time slots that cause the first node to delay the start of transmission with the second node. In some cases, the first node may receive a message content packet directed to the second node. If a message content packet is received during a node-specific transmission delay, the first node may queue the message content packet or delay its transmission until the node-specific transmission delay is complete.

[0011] As used herein, the term “TSCH network” may refer to a computer network implementing a Time Slot Channel Hopping ("TSCH") protocol. A TSCH network may, but may not, be a low-power or lossy computer network. In some cases, a TSCH network may include one or more nodes that operate with constraints on one or more of the following: processing power, memory, or energy, e.g., a battery-powered computing device. In addition, a TSCH network may include one or more nodes that are characterized by one or more of the following: a high rate of data message loss (e.g., packet loss), low data rate, or instability in the communication paths between nodes on the computer network.

[0012] In some cases, a TSCH network may include one or more nodes organized according to a routing protocol, such as a protocol for identifying communication paths between two nodes (or three or more nodes) on the TSCH network. Data messages can be transmitted between two or three or more nodes via the identified communication paths. In some cases, the routing protocol identifies a root node (e.g., the root of a communication path). For convenience, and not as an limitation, a routing relationship between two nodes (or three or more nodes) may be called a parent-child relationship. For example, a TSCH network may include a first node configured to transmit messages, such as messages directed to the root node, through a second node. In this exemplary embodiment, the first node may be said to have a child state with respect to the second node, and the second node may be said to have a parent state with respect to the first node. In some cases, a node in a TSCH network may have a parent state with respect to a particular node and a child state with respect to additional nodes. In the above exemplary embodiment, the second node may have a child state with respect to additional nodes in the TSCH network, such as the root node. In some cases, a TSCH network may implement routing protocols according to one or more standards, such as RFC6550 for "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks."

[0013] As used herein, the term “node” may refer to a computing device configured to receive or send messages in a computer network. A node may include, but is not limited to, a router, gateway, endpoint, collector, or any other suitable type of computing device. In some cases, a node may be a virtual node, such as a node implemented as a software-based computing device (e.g., a cloud computing network, a virtual server).

[0014] As used herein, the terms “message” or “data message” may refer to a group of one or more data packets configured to be transmitted between two or more nodes, such as nodes in a TSCH network. A data message may contain information such as information about the node sending the packets (e.g., performance information of the sending node), information from additional nodes on the TSCH network, information from additional computing systems (e.g., computing systems outside the TSCH network), or any other appropriate information. A data message may contain multiple parts, such as one or more message initiation packets or message content packets. In addition, a message initiation packet may contain one or more mode switching packets or header packets. In some cases, an exemplary node on a TSCH network may send a message initiation packet (or a portion of a message initiation packet) to several additional nodes on the TSCH network, such as by broadcasting a mode switching packet to any node within communication distance. In addition, the exemplary node may send the message content packet to specific additional nodes, such as the exemplary node’s parent or child, configured to utilize the data contained in the message content packet. For example, a particular additional node may be configured to modify its own behavior based on the data in the message content packet, or to send the data to an additional parent or child, or to perform other appropriate uses (or combinations of uses) of the data.

[0015] As used herein, the term “communication path” may refer to a link between nodes that enables nodes to send and receive messages via the communication path. A communication path may be established between nodes via any suitable communication technology, such as wired technology (e.g., network cable) or wireless technology (e.g., Wi-Fi, Bluetooth, cellular modem), or a combination of wired and wireless technologies.

[0016] Referring to the drawings, Figures 1A and 1B (collectively referred to as Figure 1 in this specification) illustrate an exemplary TSCH network 100 including multiple nodes. The nodes in the TSCH network 100 may include a root node 110 and one or more additional nodes such as nodes 111, 112, 113, 114, 115, and 116. In some cases, each of nodes 110-116 may be configured to send and receive messages. In addition, the root node 110 may be configured to communicate with one or more additional computer networks, such as additional TSCH networks or non-TSCH networks. In addition, each of nodes 110-116 may have a communication path to one or more additional nodes in the TSCH network 100. For example, nodes 110-116 may communicate via wireless communication technology (e.g., sending and / or receiving messages). For example, nodes 111 and 112 may communicate with each other.

[0017] In some embodiments, the TSCH network 100 is organized based on a routing protocol. Based on the routing protocol, for example, each of nodes 110-116 may establish one or more routing relationships with one or more additional nodes. In some cases, routing relationships between two or more nodes may indicate, for each node, a parent or child state with respect to one or more additional nodes in the TSCH network 100. Based on the routing relationships, the TSCH network 100 may have a single root node (such as root node 110), each non-root node may have a single parent node, and each non-root node may or may not have one or more child nodes.

[0018] Figure 1 illustrates an exemplary set of routing relationships that may be established within the TSCH network 100. For illustrative purposes, exemplary parent-child relationships are illustrated by solid lines between the parent node and the child node, and arrows point from child to parent. In the TSCH network 100, messages can be transmitted from a parent node to a child node, or from a child node to a parent node. The root node 110 may establish one or more child relationships with one or more additional nodes within the TSCH network 100. For example, the root node 110 may establish relationships with nodes 112 and 115, which indicate the parent state of node 110 and the child states of nodes 112 and 115. In addition, the root node 110 may establish additional relationships with additional nodes outside the TSCH network 100 (e.g., relationships with additional nodes in an additional computer network). In some cases, each of the non-root nodes 111-116 may establish a parent relationship with an additional node. Furthermore, non-root nodes 111-116 may establish one or more child relationships with one or more of the additional nodes. For example, node 112 may establish a relationship with node 111, which indicates the parent state of node 112 and the child state of node 111. In addition, node 115 may establish relationships with nodes 116 and 114. The relationship between node 115 and node 116 may indicate the child state of node 116 and the parent state of node 115. The relationship between node 115 and node 114 may indicate the child state of node 114 and the parent state of node 115. Table 1 summarizes the exemplary parent-child relationships illustrated in Figure 1.

[0019] [Table 1]

[0020] In some cases, one or more nodes within the TSCH network 100 may store information regarding additional nodes within the TSCH network 100 in a node state table (e.g., a lookup table) that indicates the state of one or more of the additional nodes. For example, each particular node may generate or modify a node state table that stores information regarding each additional node with which the particular node can communicate. For example, node 115 may generate a node state table that stores information regarding root node 110, node 116, and node 114. In some cases, the node state table of a particular node may include information regarding additional nodes that have a parent or child relationship with the particular node, such as table entries that indicate a parent relationship, a child relationship, a relative signal strength, or additional information related to communication with the additional nodes. Additionally, the node state table of a particular node may include information regarding additional nodes with which the particular node can communicate. For example, if node 115 does not have a parent or child relationship with node 112 but can communicate with node 112 (e.g., is within the distance of a signal transmitted from node 112), node 115 may maintain a node state table entry for node 112. In some cases, the node state table entry associated with node 112 may indicate the absence of a parent or child relationship or additional information related to communication with node 112.

[0021] In the TSCH network 100, one or more messages, such as data messages transmitted between a parent node or child node, may be transmitted between two or more nodes 110-116. Messages transmitted within the TSCH network 100 may include one or more of the following: mode switching packets, message header packets, or message content packets. In the TSCH network 100, the TSCH protocol may be used for transmission between nodes. For example, nodes involved in the transmission of a data message (e.g., a receiving node, a sending node) may reserve one or more communication channels or one or more time blocks for message transmission. The communication channels or time blocks may be reserved according to the TSCH protocol.

[0022] In some embodiments, node 114 may generate (or receive) data for messages, such as information about the operation of node 114. In addition, node 114 may also generate (or receive) data messages 120. Data messages 120 may include message content packets describing data from node 114. In addition, data messages 120 may include message start packets, such as one or more of a mode switching packet 122 or a message header packet 124. In addition, data messages 120 may include one or more message content packets, such as a message content packet 126. For convenience, not as an limitation, data messages 120 are described as having a message content packet 126, but other embodiments are possible. For example, a particular data message on the TSCH network 100 may include multiple message content packets describing data (e.g., having a size larger than a single message content packet).

[0023] Node 114 may send a message start packet of data message 120 to a plurality of nodes on the TSCH network 100. For example, the message start packet of data message 120 may be transmitted to each node within the communication range of node 114 via, for example, a broadcast to at least node 115 and node 113 having a parent or child relationship with node 114. Based on the message start packet, one or more of node 113 or node 115 may determine one or more of the source node or the destination node of data message 120. For example, header packet 124 may include header information identifying node 115 as the destination node targeted, or additional header information identifying node 114 as the source node. In some cases, one or more of node 114 or node 115 may enter a transmission state, such as by reserving a channel and one or more time blocks for the communication of data message 120.

[0024] Based on the information in the message initiation packet, node 113 may determine that one or more of the originating and receiving nodes, namely node 114 or node 115, are involved in the transmission. For example, node 113 may determine that node 114 is the originating node and node 115 is the receiving node for the message content packet 126 associated with the message initiation packet. In addition, node 113 may determine the transmission time of the data message 120, such as the number of time slots. In some cases, the transmission time may indicate the duration of the transmission between the originating and receiving nodes. For example, the transmission time of the data message 120 may include the data of the data message 120, such as the number of time slots in which the message content packet 126 is transmitted over the communication channel in the TSCH network 100. The transmission time may be determined based on information from the message header packet 124, such as header data describing the size of the message content packet 126, the baud rate of the communication channel in which the data message 120 is transmitted, the length of the time slots, or other appropriate information regarding the transmission of the data message 120. For example, node 113 may calculate the transmission time by multiplying (or combining) the size of the message content packet 126 by the baud rate of the communication channel through which the data message 120 is transmitted.

[0025] In some embodiments, node 113 may modify one or more node-specific transmission delays based on the transmission time of data message 120. For example, node 113 may modify a node-specific transmission delay associated with node 114. The node-specific transmission delay may indicate a backoff for node 114. For example, node 113 may modify a node-specific transmission delay to indicate a number of backoff time slots for node 114. During that number of backoff time slots, node 113 delays (or avoids) the initiation of transmission with node 114.

[0026] As a non-limiting example, if a message initiation packet indicates that five time slots are required for the transmission of data message 120, node 113 may modify its node-specific transmission delay to indicate five backoff time slots for node 114. If node 113 receives additional data messages for node 114 during the node-specific transmission delay, node 113 may delay the transmission of the additional data messages. For example, if node 113 generates (or receives) data message 140 for transmission to node 114, node 113 may queue (or delay) data message 140 until the five backoff time slots are complete.

[0027] In some cases, node-specific transmission delays may be stored in a node state table. For example, node 113 may maintain a node state table with an entry associated with node 114. Node 113 may modify the table entry to indicate the communication state of node 114 (e.g., "transmittable" state, "untransmittable" state). In addition, node 113 may modify the table entry to indicate node-specific transmission delays associated with node 114. In some cases, node 113 may modify an additional node-specific transmission delay associated with node 115, for example, if node 113 can communicate with node 115 but does not have a parent or child relationship with node 115.

[0028] In some embodiments, a node may determine a node-specific transmission delay based on an estimated transmission time. The estimated transmission time may be calculated from information indicated by the message initiation packet combined with information determined by the node. In some cases, the estimated transmission time may be calculated based on information associated with the communication mode. In addition, the estimated transmission time may be calculated based on information associated with transmissions to or from the node.

[0029] Figure 1B is a diagram of exemplary transmission distances in a TSCH network 100 that can be associated with specific communication modes. Within a transmission distance 155, for example, one or more of nodes 113, 114, or 115 may be included. The transmission distance 155 can be associated with a first communication mode so that the nodes included within the transmission distance 155 can communicate via the first communication mode. In the TSCH network 100, the first communication mode may be characterized by long-distance transmission at a relatively low transmission speed (e.g., low baud rate, low bandwidth). In addition, one or more of nodes 114 or 115 may be included within a transmission distance 165. The transmission distance 165 can be associated with a second communication mode so that the nodes included within the transmission distance 165 can communicate via the second communication mode. In the TSCH network 100, the second communication mode may be characterized by short-distance transmission at a relatively high transmission speed (e.g., high baud rate, high bandwidth). In some cases, the transmission distances 155 and 165 may be affected by the characteristics of the nodes in the TSCH network 100, such as the receiving sensitivity of the node antenna, the orientation of the node antenna, the transmitting power of the node, the available battery power of the node, or additional characteristics of one or more nodes. In addition, the transmission distances 155 and 165 may be affected by the characteristics of the TSCH network 100, such as the base baud rate of the TSCH network 100, the geographical distance between nodes, the physical features located between nodes (e.g., buildings), or additional characteristics of the TSCH network 100.

[0030] In the TSCH network 100, one or more of the nodes 110-116 may estimate the transmission time for transmission between additional nodes. For example, node 113 may complete a transmission to node 114, such as the transmission of data message 150. In some cases, data message 150 may include data directed to node 115 (or the parent of node 115). After completing the transmission of data message 150 to node 114, node 113 may receive a message initiation packet from node 114. The message initiation packet may be associated with data message 160 for transmission from node 114 to node 115. In some cases, the message initiation packet received by node 113 may include a mode switching packet, such as a mode switching packet indicating a second communication mode for the transmission of data message 160. In addition, the message initiation packet received by node 113 may omit the message header packet. For example, node 114 may transmit a mode switching packet associated with the data message 160 via a first communication mode associated with a transmission distance 155. In addition, node 114 may transmit additional packets associated with the data message 160, such as a header and message content packets, via a second communication mode associated with a transmission distance 165.

[0031] For example, in response to receiving a mode-switching packet associated with data message 160 via a first communication mode, node 113 may estimate the transmission time of data message 160. In some cases, the estimated transmission time may be calculated based on a combination of information contained in the mode-switching packet from node 114 and information stored (or available) at node 113. For example, node 113 may determine that the mode-switching packet is associated (or possibly associated) with data message 150 containing data directed to node 115. In addition, node 113 may determine that the second communication mode indicated by the mode-switching packet has one or more specific transmission characteristics, such as baud rate, bandwidth, or other transmission characteristics. Based on a combination of information from the mode-switching packet and information available to node 113, node 113 may determine the estimated transmission time of data message 160. For example, node 113 may calculate the estimated transmission time based on the size of the data directed to node 115 multiplied (or combined with) the baud rate of the second communication mode. In some cases, node 113 may modify the node-specific transmission delay associated with node 114. For example, node 113 may modify the node-specific transmission delay to indicate the number of backoff time slots calculated from the estimated transmission time. In some cases, one or more nodes in the TSCH network 100 may reduce or avoid failures of transmission attempts with additional nodes, for example, by calculating the node-specific transmission delay of the additional nodes. In addition, a particular node may determine the node-specific transmission delay based on information received in the message initiation packet, information available to the particular node, or a combination of such information.

[0032] Figure 2 is a flowchart illustrating an example of process 200 for reducing transmission failures between nodes in a TSCH network. In some embodiments, such as those described with respect to Figure 1, a computing device configured as a node in a TSCH network may perform the operations described in Figure 2 by executing appropriate program code. For illustrative purposes, process 200 is described with reference to the example shown in Figure 1. However, other embodiments are also possible.

[0033] In block 210, process 200 may include receiving a message initiation packet from a specific node in the TSCH network. The message initiation packet may be received by additional nodes in the TSCH network, such as a message initiation packet received by the first node from a second node. In some cases, the message initiation packet may include one or more of a mode switching packet or a message header packet. For example, node 113 may receive a message initiation packet from node 114, such as one or more of a mode switching packet 122 or a message header packet 124.

[0034] In block 220, process 200 may include determining the transmission time of one or more message content packets associated with the message start packet. The transmission time may, for example, indicate the duration of one or more message content packets. For example, the transmission time may indicate the number of time slots reserved (for example, according to the TSCH protocol) for the transmission of the message content packets. Node 113 may, for example, determine the transmission time associated with message content packet 126.

[0035] In some cases, the transmission time may be determined based on information contained in the message initiation packet. For example, node 113 may determine the transmission time of the message content packet 126 based on information contained in the message header packet 124, such as information describing one or more of the size of the message content packet 126 or the bandwidth of the communication channel through which the data message 120 is transmitted. In addition, the transmission time may be determined based on a combination of information in the message initiation packet and information determined by the node that received the message initiation packet. For example, node 113 may determine the estimated transmission time of the message content packet in the data message 160 based on information in the mode switching packet (e.g., the communication mode selected for the transmission of the data message 160) combined with information available to node 113 (e.g., the size of the message content packet transmitted in the preceding data message 150).

[0036] In block 230, process 200 may include correcting a node-specific transmission delay associated with a particular node (for example, from which a message initiation packet is received). In some cases, the node-specific transmission delay may indicate the number of backoff time slots associated with the particular node. In addition, the node-specific transmission delay may indicate a delay in the initiation of transmission to a particular node by the number of backoff time slots. For example, node 113 may correct the node-specific transmission delay of node 114. The node-specific transmission delay may indicate the number of backoff time slots for node 114. In addition, the node-specific transmission delay may indicate a backoff (for example, the number of backoff time slots) determined based on the transmission time determined or estimated for node 114. In some cases, the node-specific transmission delay indicates a backoff associated with a particular transmission to and from a particular node. For example, node 113 may calculate a first number of backoff time slots associated with the transmission of data message 120 by node 114 based on the transmission time of message content packet 126. In addition, node 113 may calculate a second number of backofftime slots associated with the transmission of data message 160 by node 114, based on the estimated transmission time of data message 160.

[0037] In block 240, process 200 may include determining additional message content packets that have a destination for a particular node. For example, a first node that calculates a node-specific transmission delay associated with a second node may generate (or receive) additional message content packets for the second node, such as a data message 140 generated or received by node 113. Node 113 may determine that the data message 140 has a destination for node 114 (or the parent of node 114).

[0038] In block 250, process 200 may include queuing or delaying additional message content packets. In some cases, delaying additional message content packets may be based on a node-specific transmission delay associated with a particular node. In addition, delaying additional message content packets may include queuing additional message content packets for transmission to a particular node after a node-specific transmission delay. For example, node 113 may queue data message 140 based on a node-specific transmission delay associated with node 114. In addition, node 113 may queue data message 140 for transmission after a number of backoff time slots indicated by the node-specific transmission delay.

[0039] In some embodiments, a specific node in the TSCH network, such as a node performing one or more operations related to process 200, may calculate a backoff value associated with additional nodes in the TSCH network. In some cases, the backoff value may include a default backoff value, such as a default value that can be calculated using one or more characteristics of the specific node or the additional nodes. In addition, the backoff value may include a modified backoff value, such as a value modified from the default value. In some cases, the specific node may modify the backoff value based on information about data messages, such as data messages transmitted to one or more of the specific node or the additional nodes. For example, the first node may modify the backoff value associated with the second node based on information contained in a message initiation packet received from the second node. In addition, the first node may modify the backoff value associated with the second node based on information available to the first node regarding the previous transmission to the second node.

[0040] In some cases, a particular node may calculate multiple backoff values ​​associated with multiple additional nodes in the TSCH network. For example, a particular node may calculate backoff values ​​for all additional nodes in the TSCH network, for each additional node with which the particular node can communicate, for each additional node that has a parent or child relationship with the particular node, or for any other suitable group of nodes in the TSCH network. In some cases, a particular node may generate or modify a node state table containing one or more calculated backoff values. For example, a particular node may generate or modify multiple node state table entries associated with multiple additional nodes. In some cases, each node state table entry may indicate a backoff value associated with each additional node, such as a default backoff value or a modified backoff value. In addition, each node state table entry may indicate a communication state associated with each additional node. In some cases, for example, if an additional node is unable to receive a transmission during a node-specific transmission delay or a number of backoff time slots, the communication state of the additional node may be modified (e.g., by the particular node) to indicate an updated communication state.

[0041] Figure 3 is a flowchart illustrating an example of process 300 for calculating one or more backoff values ​​or backoff time slots for a node in a TSCH network. In some embodiments, such as those described with respect to Figures 1 and 2, a computing device configured as a node in a TSCH network may perform the operations described in Figure 3 by executing appropriate program code. For illustrative purposes, process 300 is described with reference to the examples shown in Figures 1 and 2. However, other embodiments are possible. In some cases, one or more operations described with respect to process 300 may be performed in combination with one or more operations described with respect to process 200.

[0042] In block 310, process 300 may include determining that the message initiation packet is a mode switching packet. The mode switching packet may be received by a first node in the TSCH network from a second node in the TSCH network. In some embodiments, the second node may be a specific node described with respect to process 200 (though not necessarily required). In some cases, the mode switching packet may indicate a communication mode to be applied to the message content packet associated with the mode switching packet. In addition, the communication mode may be applied to the message content packet by the second node. For example, node 113 may receive a mode switching packet associated with data message 160 from node 114. In addition, the mode switching packet may indicate a second communication mode to be applied to the message content packet of data message 160.

[0043] In block 320, process 300 may include calculating the number of backoff time slots associated with the communication mode. In addition, the number of backoff time slots may be associated with a second node. In some cases, the number of backoff time slots may be calculated based on information associated with one or more of the mode switching packets, the first node, or the second node. For example, the first node may determine its own receive sensitivity, such as receive sensitivity based on antenna strength, noise floor, battery status, or other characteristics of the first node. In addition, the first node may determine the transmit power of the second node, such as transmit power indicated by the mode switching packets or additional transmission from the second node. In some cases, one or more of the receive sensitivity or transmit power is calculated based on the transmission history between the first node and the second node. For example, node 113 may calculate one or more of node 113's receive sensitivity or node 114's transmit power based on the transmission history between node 113 and node 114.

[0044] In some cases, node 113 may determine, based on one or more of the calculated received sensitivity or transmitted power, whether node 113 is included in or excluded from the transmission distance 165 (or both). In some cases, node 113 may calculate its own additional transmitted power. The additional transmitted power may be calculated based on antenna strength, noise floor, battery condition, or other characteristics of node 113. In addition, node 113 may provide the additional transmitted power to one or more additional nodes on the TSCH network 100, for example, node 114, or to one or more child nodes of node 113.

[0045] In block 330, process 300 may include calculating one or more default backoff values, such as the default backoff values ​​for one or more nodes on the TSCH network. In some cases, the default backoff values ​​may be associated with a particular communication mode from a set of communication modes. For example, a first node may calculate one or more default backoff values ​​associated with a second node. Each of the default backoff values ​​may be associated with a particular communication mode for the second node, for example, a particular communication mode from a set of communication modes. In some embodiments, the backoff values ​​may describe one or more values ​​for calculating the number of backoff time slots, such as the duration of time (e.g., 100 ms), the duration of a time slot (e.g., 25 ms), the characteristics of a communication mode (e.g., 50 kbps), or other appropriate values.

[0046] For example, node 113 may calculate multiple default backoff values ​​associated with node 114, such as a first default backoff value associated with a first communication mode (e.g., associated with a transmission distance of 155) and a second default backoff value associated with a second communication mode (e.g., associated with a transmission distance of 165). In some embodiments, the multiple default backoff values ​​may be calculated based on a transmission history, such as a transmission history between the first node and the second node. For example, node 113 may calculate a first default backoff value and a second default backoff value based on a transmission history between node 113 and node 114.

[0047] In some cases, one or more operations associated with block 330 may be repeated, such as a node-by-node iteration for a group of nodes in the TSCH network. The first node may determine multiple default backoff values ​​for each node in an additional group of nodes in the TSCH network (for example, for each communication mode in a set of communication modes). The additional group of nodes may include, for example, each node in the TSCH network, each node that the first node can communicate with, each node that has a parent or child relationship with the first node, or another suitable group of nodes in the TSCH network.

[0048] In block 340, process 300 may include identifying a specific default backoff value from a set of default backoff values, etc. The specific default backoff value may be associated with a communication mode indicated by a mode switching packet. In some cases, identifying a specific default backoff value may be in response to receiving a mode switching packet. For example, in response to receiving a mode switching packet associated with data message 160, node 113 may identify a specific default backoff value associated with node 114. In addition, node 113 may identify a specific default backoff value based on information contained in the mode switching packet associated with data message 160. For example, in response to determining that the mode switching packet identifies a second communication mode to be applied to data message 160, node 113 may identify a second default backoff value as a specific default backoff value.

[0049] In block 350, process 300 may determine that a mode switching packet is associated with a prior transmission, such as a prior transmission from a first node to a second node. In some cases, the association between a mode switching packet and a prior transmission is determined based on the message content of the prior transmission, such as message content directed to the parent of the second node. For example, node 113 may determine that a mode switching packet associated with data message 160 is associated with a prior data message 150 transmitted from node 113 to node 114. In some cases, the association between a mode switching packet and the prior data message 150 may be determined in response to the determination that the prior data message 150 contained message content directed to node 115.

[0050] In block 360, process 300 may include modifying a specific default backoff value. In addition, a specific default backoff value may be modified based on one or more of the communication mode or the size of the preceding transmission indicated by the mode switching packet. In some cases, the first node may modify a specific default backoff value associated with one or more of the second node or communication modes. The modification of a specific default backoff value may be based on the calculation of the time slots required to transmit a data message having the size of the preceding transmission at the bandwidth (or other transmission characteristics) of the communication mode indicated by the mode switching packet. For example, node 113 may calculate the number of time slots in which the message content from the preceding data message 150 can be transmitted at the bandwidth of the second communication mode. In addition, node 113 may modify a default backoff value associated with node 114 (for example, associated with the second communication mode) to indicate the calculated number of backoff time slots.

[0051] In some embodiments, node-specific transmission delays may be generated or modified based on the modified backoff value. For example, the number of backoff time slots indicated by the node-specific transmission delay may be modified to include the number of time slots calculated for the modified backoff value.

[0052] In some embodiments, a node in a TSCH network may determine a conflict avoidance delay. This delay may be included in the node-specific transmission delay, or otherwise combined with it. In some cases, the conflict avoidance delay may be applied by a node to further reduce transmission failures in the TSCH network. For example, a particular node in a TSCH network may generate a conflict avoidance delay based on a random (or pseudo-random) number of backoff time slots. In addition, a particular node may add a conflict avoidance delay to its node-specific transmission delay. For example, if a node parent has several children, including a particular node, queuing data messages directed to the parent, the parent node may receive multiple transmission requests at the expiration of each child's node-specific transmission delay determined by the children. To reduce transmission failures resulting from multiple transmission requests from children, each child node, including a particular node, may determine its own conflict avoidance delay. In addition, each child node may modify its node-specific transmission delay to include its own conflict avoidance delay. In some cases, modifying the node-specific transmission delay to include a conflict avoidance delay can reduce transmission failures in a TSCH network.

[0053] Figure 4 shows an example of a transmission environment 400 in which a signal having communication channels and transmission times can be transmitted. For example, the transmission environment 400 may include a plurality of time slots 401a to 401s (collectively referred to herein as time slot 401). In addition, the transmission environment 400 may include a plurality of communication channels 402a to 402i (collectively referred to herein as communication channels 402). Each of the channels 402 may include one or more center frequencies or frequencies within a range. In some cases, a data message may be transmitted over one or more of the communication channels 402. In addition, a data message may be transmitted over one or more durations of the time slots 401. In some cases, the transmission environment 400 may be associated with the TSCH protocol. In addition, the transmission environment 400, or the data messages transmitted in the transmission environment 400, may conform to local or global standards. Not as an limitation, but as an example, the transmission environment 400 and / or the data message being transmitted may conform to standards set by, for example, the Federal Communications Commission (FCC), such as CFR Title 47 Part 15.

[0054] In transmission environment 400, transmission 420 may be transmitted over communication channel 402d between time slots 401b to 401h. For example, a particular node on the TSCH network may transmit a data message via transmission 420 (e.g., to a parent node or a child node). In some cases, transmission 420 may include one or more of a message initiation packet or at least one message content packet. In some cases, additional transmissions within transmission environment 400 may utilize more or fewer time slots 401.

[0055] In some embodiments, additional nodes on the TSCH network may attempt to initiate a transmission with a specific node during transmission 420. For example, an additional node may attempt to initiate transmission 410 on communication channel 402f during time slots 401d–401j. Transmission 410 may fail if the additional node is not configured to utilize one or more techniques to mitigate transmission failures, such as determining node-specific transmission delays for a particular node. In some cases, an attempt to initiate transmission 410 may inefficiently utilize resources within the transmission environment 400. For example, communication channel 402 may be reserved by the additional node for one or more of the time slots 401d–401j. In addition, reserving communication channel 402 for transmission 410 can prevent other nodes in the TSCH network from using communication channel 402 for additional transmissions, such as potentially successful transmissions with nodes not involved in transmission 420.

[0056] Figure 5 shows an example of a transmission environment 500 that may be utilized by one or more nodes configured to determine node-specific transmission delays associated with additional nodes. In some cases, the TSCH network 100 may utilize the transmission environment 500. Signals having communication channels and transmission times may be transmitted in the transmission environment 500. The transmission environment 500 may include a plurality of time slots 501a to 501s (collectively referred to herein as time slot 501). In addition, the transmission environment 500 may include a plurality of communication channels 502a to 502i (collectively referred to herein as communication channels 502). Each of the channels 502 may include one or more center frequencies or frequencies within a range. In some cases, data messages may be transmitted over one or more of the communication channels 502. In addition, data messages may be transmitted over one or more durations of the time slots 501. In some cases, the transmission environment 500 may be associated with the TSCH protocol, global standards, local standards, or other appropriate protocols or standards.

[0057] In the transmission environment 500, transmission 520 may be transmitted over communication channel 502d between time slots 501b to 501h. In some cases, transmission 520 may include the transmission of a data message 120 from node 114 to node 115. In addition, transmission 520 may include at least one message initiation packet, such as a message initiation packet 522. The message initiation packet 522 may include one or more of a mode switching packet 122 or a message header packet 124. In some cases, the message initiation packet 522 in time slot 501b may include a mode switching packet 122. In addition, the message header packet 124 may be transmitted as a subsequent packet, such as a packet in time slot 501c.

[0058] In some embodiments, one or more additional nodes, such as node 113, may receive the message initiation packet 522. In addition, one or more additional nodes may receive node 114 or node 115 Each node may generate or correct a node-specific transmission delay associated with one or more of the following. In the transmission environment 500, resources can be used more efficiently (compared to, for example, the transmission environment 400) by utilizing one or more techniques to reduce transmission failures such as node-specific transmission delays. For example, node 113 may initiate transmission 540 associated with data message 140 after the completion of the node-specific transmission delay associated with transmission 520. For example, in response to node 114 deciding to be involved in transmission 520, node 113 may queue or delay data message 140. In addition, node 113 may initiate transmission 540 after the completion of the node-specific transmission delay associated with node 114.

[0059] In some embodiments, a node may modify the queue position of one or more data messages based on node-specific transmission delays. For example, during node-specific transmission delays of node 114, node 113 may modify its message queue to transmit additional data messages for additional nodes (e.g., other than node 114 or node 115). If node 113 receives additional data messages during node-specific transmission delays, node 113 may modify the queue position of the additional data messages to a position prior to the queue position of data message 140, for example. In addition, node 113 may initiate transmission 580 during node-specific transmission delays, for example, to transmit additional data messages to additional nodes before transmitting data message 140.

[0060] In some cases, resources within the transmission environment 500 may be utilized more efficiently during node-specific transmission delays associated with transmission 520. For example, node 113 may initiate transmission 580 during node-specific transmission delays, for example, while node 113 is not involved in a transmission attempt with node 114 which is occupied. As an additional example, another node in the TSCH network 100 may utilize one or more time slots before transmission 540, such as a potentially successful transmission via communication channel 502f with a node not involved in transmission 520. In some cases, the operation for determining node-specific transmission delays may involve communication channel 502 or time slots. 501 This may not include reserving a time slot. In addition, the operation of determining node-specific transmission delays may allow nodes in the TSCH network 100 to reduce transmission failures within the transmission environment 500 without occupying resources in the transmission environment 500 (e.g., channel 502, time slot 501).

[0061] Any suitable computing system or group of computing systems can be used to perform the operations described herein. For example, Figure 6 shows an example of a computing environment that can determine the node-specific transmission delay of nodes in a TSCH network according to a particular embodiment.

[0062] An example of node 601 shown in the diagram may include one or more processors 602 communicatively coupled to one or more memory devices 604. The processors 602 may execute computer executable program code or access information stored in the memory devices 604. Examples of processors 602 may include microprocessors, application-specific integrated circuits ("ASICs"), field-programmable gate arrays ("FPGAs"), or any other suitable processing devices. The processors 602 may include any number of processing devices, including one.

[0063] The memory device 604 may include any suitable non-temporary computer-readable medium for storing one or more of the following: node-specific transmission delays 620, node state tables 630, message start packets 640, data messages 650, or other received or determined values ​​or data objects. The computer-readable medium may include any electronic, optical, magnetic, or other storage device that can provide the processor with computer-readable instructions or other program code. Non-limiting examples of the computer-readable medium may include magnetic disks, memory chips, ROMs, RAMs, ASICs, optical storage devices, magnetic tapes or other magnetic storage devices, or any other medium from which the processing device can read the instructions. The instructions may include processor-specific instructions generated by a compiler or interpreter from code written in any suitable computer programming language, including, for example, C, C++, C#, Visual Basic, Java, Python, Perl, JavaScript, and ActionScript.

[0064] Node 601 may also include several external or internal devices, such as input and output devices. For example, Node 601 is shown with an input / output ("I / O") interface 608 that can receive input from an input device or provide output to an output device. Node 601 may also include a bus 606 that can communicatively connect one or more components of Node 601.

[0065] Node 601 may execute program code that configures processor 602 to perform one or more of the operations described herein with respect to Figures 1 to 5. The program code may include, for example, a node-specific transmission delay 620, a node state table 630, a message initiation packet 640, a data message 650, or operations related to one or more of other suitable applications or memory structures that perform one or more of the operations described herein. The program code may reside in memory device 604 or any suitable computer-readable medium and may be executed by processor 602 or any other suitable processor. In some embodiments, the program code, node-specific transmission delay 620, node state table 630, message initiation packet 640, and data message 650 described above may be stored in memory device 604 as shown in Figure 6. In additional or alternative embodiments, one or more of the node-specific transmission delay 620, node state table 630, message initiation packet 640, data message 650, or program code described above may be stored in one or more memory devices accessible over a data network, such as a memory device accessible over a cloud service.

[0066] Node 601, shown in Figure 6, may include at least one network interface 610. The network interface 610 may include any device or group of devices suitable for establishing a wired or wireless data connection to one or more data networks 612. Non-exclusive examples of the network interface 610 may include an Ethernet network adapter, a modem, and the like. One or more nodes, such as node 660, may be connected to node 601 via network 612. Network 612 may include a TSCH network as described herein. In some cases, network 612 may include additional networks such as (but not limited to) the Internet, a private network (including a virtual private network), or any other suitable network. Node 601 may communicate with one or more of the nodes 660 using the network interface 610.

[0067] General Considerations In order to provide a complete understanding of the claimed subject matter, numerous specific details are provided herein. However, those skilled in the art will understand that the claimed subject matter may be implemented without these specific details. In other instances, methods, apparatus, or systems that are publicly known to those skilled in the art are not described in detail so as not to obscure the claimed subject matter.

[0068] Unless otherwise specified, any use of terms such as “processing,” “computing,” “calculating,” “determining,” and “identifying” throughout this specification is understood to refer to the operation or process of a computing device, such as one or more computers or one or more similar electronic computing devices, that manipulates or transforms data represented as physical electronic or magnetic quantities in the memory, registers, or other information storage devices, transmission devices, or display devices of a computing platform.

[0069] The one or more systems discussed herein are not limited to any particular hardware architecture or configuration. A computing device may include any suitable arrangement of components that provide results conditional on one or more inputs. A suitable computing device includes a multipurpose microprocessor-based computer system that accesses stored software to program or configure a computing system from a general-purpose computing device to a dedicated computing device implementing one or more embodiments of this subject. Any suitable programming language, scripting language, or other type of language or combination of languages ​​may be used to implement the teachings contained herein in software to be used for programming or configuring a computing device.

[0070] Embodiments of the methods disclosed herein may be carried out in the operation of such computing devices. The order of the blocks presented in the above examples can be changed, and for example, the blocks can be rearranged, combined, and / or divided into subblocks. Certain blocks or processes can be carried out in parallel.

[0071] The use of “adapted to” or “configured to” in this specification means an open, inclusive expression that does not exclude devices adapted or configured to perform additional tasks or steps. In addition, the use of “based on” means an open, inclusive expression that a process, step, calculation, or other operation “based on” one or more described conditions or values ​​may actually be based on additional conditions or values ​​beyond those described. The headings, lists, and numbering included herein are for illustrative purposes only and are not intended to limit the scope of the explanation.

[0072] While the subject matter is described in detail with respect to its specific embodiments, those skilled in the art will understand that, having attained the above understanding, modifications, variations, and equivalents of such embodiments can be readily constructed. Therefore, it should be understood that this disclosure is presented for illustrative purposes only, not limitation, and does not preclude such modifications, variations, and / or additional inclusions to the subject matter that would be readily apparent to those skilled in the art.

Claims

1. A method for managing node transmission in a computer network using a time-slot channel hopping protocol ("TSCH network"), the method comprising an operation performed by the processor of a first node included in the TSCH network, the operation being: The first node receives a message initiation packet from the second node, The first node determines the transmission time of the message content packet associated with the message initiation packet based on the message initiation packet, The first node modifies a node-specific transmission delay associated with the second node, wherein the node-specific transmission delay indicates the number of backoff time slots that cause the first node to delay the start of transmission to the second node. The first node determines an additional message content packet that has a destination for the second node, The first node queues the additional message content packets for transmission to the second node after the node-specific transmission delay, based on the node-specific transmission delay. Methods that include...

2. It is determined that the message initiation packet is a header packet from the second node, Determining the size of the message content packet associated with the header packet, Determining the communication mode indicated by the header packet, The number of backofftime slots is calculated based on the size of the message content packet and the communication mode. The method according to claim 1, further comprising:

3. The first node determines, based on the message initiation packet, the receiving node for the message content packet associated with the message initiation packet, and further determines that the receiving node is a node other than the first node. Correcting the node-specific transmission delay associated with the second node is a response to the determination that the receiving node is a node other than the first node. The method according to claim 1.

4. The determination that the message initiation packet is a mode switching packet from the second node, wherein the mode switching packet indicates and determines the communication mode applied to the message content packet by the second node. Determining the receiving sensitivity of the first node, Determining the transmit power of the second node, Based on the receiving sensitivity and the transmitting power, the number of backoff time slots associated with the communication mode is calculated, The method according to claim 1, further comprising:

5. The method according to claim 4, wherein one or more of the receiving sensitivity or the transmitting output power are determined based on the transmission history between the first node and the second node.

6. The calculation of a plurality of default backoff values ​​based on the transmission history between the first node and the second node, wherein each of the plurality of default backoff values ​​is associated with a specific communication mode within a set of communication modes. In response to receiving the mode switching packet, identify a specific default backoff value associated with the communication mode indicated by the mode switching packet, In response to determining that the mode switching packet is associated with a prior transmission from the first node to the second node, (i) modify the specific default backoff value based on the size of the prior transmission and (ii) the communication mode indicated by the mode switching packet. It further includes, Calculating the number of backoff time slots associated with the communication mode includes calculating the number of backoff time slots based on a modified backoff value. The method according to claim 4.

7. Determining the aforementioned additional message content packets is: Receiving the additional message content packets from the third node, or The first node generates the additional message content packets, The method according to claim 1, comprising one or more of the above.

8. Updating the node state table to include the communication state associated with the second node, wherein the updated communication state indicates that the second node is unable to receive transmissions during the number of backoff time slots. The method according to claim 1, further comprising:

9. The first node identifies a queued message packet having a destination for the third node, wherein the queued message packet has a queue position after the additional message content packet. In response to the third node determining that it can receive the transmission during the number of backoff time slots, the queue position of the queued message packets is modified so that it precedes the additional message content packets. The method according to claim 1, further comprising:

10. The method according to claim 1, wherein correcting the node-specific transmission delay includes adjusting the number of backoff time slots to include a conflict avoidance delay.

11. A computer network node configured to manage node transmission in a computer network using a time-slot channel hopping protocol ("TSCH network"), wherein the computer network node is Receiving message initiation packets from additional nodes in the aforementioned computer network, Based on the message initiation packet, the additional node determines the number of backoff time slots in which it transmits the message content packet associated with the message initiation packet, Correcting node-specific transmission delays associated with the additional nodes, such that the node-specific transmission delays indicate that the additional nodes are unable to receive transmissions during the number of backoff time slots. Receiving additional message content packets that have a destination for the aforementioned additional node, Based on the node-specific transmission delay, the additional message packets are queued for transmission after the aforementioned number of backoff time slots, A computer network node, including a processor configured to perform operations including those mentioned above.

12. Determining the aforementioned number of backoff time slots is It is determined that the message initiation packet is a header packet from the additional node, Determining the size of the message content packet associated with the header packet, Determining the communication mode indicated by the header packet, Calculating the number of backoff time slots based on the size of the message content packet and the communication mode, A computer network node according to claim 11, including the computer network node described in claim 11.

13. The aforementioned processor, The computer network node determines, based on the message initiation packet, the receiving node for the message content packet associated with the message initiation packet. It is further configured in this way, The receiving node is a node other than the computer network node, Correcting the node-specific transmission delay associated with the additional node is a response to the determination that the receiving node is a node other than the computer network node. A computer network node according to claim 11.

14. Determining the aforementioned number of backoff time slots is Determining that the message initiation packet is a mode switching packet from the additional node, the mode switching packet indicates or determines the communication mode used by the additional node. Determining the receiving sensitivity of the aforementioned computer network node, Determining the transmit power output of the additional node, Based on the receiving sensitivity and the transmitting power, the number of backoff time slots associated with the communication mode is identified, A computer network node according to claim 11, including the computer network node described in claim 11.

15. The computer network node according to claim 14, wherein one or more of the receiving sensitivity or the transmitting power are determined based on the transmission history between the computer network node and the additional node.

16. The aforementioned processor, Based on the transmission history between the computer network node and the additional node, a plurality of default backoff values ​​are calculated. The configuration is further configured such that each of the multiple default backoff values ​​is associated with a specific communication mode within a set of communication modes. The aforementioned processor, In response to receiving the mode switching packet, identify a specific default backoff value associated with the communication mode indicated by the mode switching packet. In response to determining that the mode switching packet is associated with a prior transmission from the computer network node to the additional node, the specific default backoff value is modified based on (i) the size of the prior transmission and (ii) the communication mode indicated by the mode switching packet. It is further configured in this way, Determining the number of backoff time slots for which the additional nodes transmit the message content packets associated with the message initiation packet includes calculating the number of backoff time slots based on a modified backoff value. A computer network node according to claim 14.

17. Receiving the aforementioned additional message content packets means that Receiving the additional message content packets from further nodes in the computer network, or The computer network node generates the additional message content packets. A computer network node according to claim 11, comprising one or more of the above.

18. The aforementioned processor, Update the node state table to include the communication state associated with the additional node. The further configured and updated communication state indicates that the additional node is unable to receive transmissions during the aforementioned number of backoff time slots. A computer network node according to claim 11.

19. The aforementioned processor, The computer network node identifies a queued message packet that has a destination for further nodes in the computer network and has a queue position after the additional message packet. In response to determining that the additional nodes can receive the transmission during the aforementioned number of backoff time slots, the queue position of the queued message packets is modified so that it precedes the additional message content packets. A computer network node according to claim 11, further configured as follows.

20. Correcting the node-specific transmission delay includes adjusting the number of backofftime slots to include a conflict avoidance delay, according to claim 11.

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