A reliable multi-source broadcast method for wireless single-hop networks based on piggyback acknowledgement

Abstract

This invention relates to a reliable multi-source broadcast method for single-hop wireless networks based on piggyback acknowledgment. The method is characterized by: multiple broadcast source nodes in the single-hop wireless network, each source node having multiple messages to broadcast; all nodes communicating via the same wireless channel and each equipped with an omnidirectional antenna; channel access using a p-CSMA mechanism; and packet loss including transmission collisions and random transmission losses. This method effectively suppresses unnecessary message retransmissions by piggybacking acknowledgments of the number of times other source nodes have successfully transmitted messages when sending messages, thereby improving broadcast efficiency and channel utilization.

Description

Technical Field

[0001] This invention belongs to the field of wireless broadcasting technology, specifically relating to a multi-source broadcasting method for single-hop wireless networks based on piggyback acknowledgments. This method primarily improves message broadcasting efficiency by piggybacking acknowledgments when other nodes broadcast messages. Background Technology

[0002] In single-hop wireless networks, when the MAC layer uses a shared wireless channel based on p-CSMA for access, transmission collisions and random transmission errors can both lead to message transmission failures. To improve the reliability of message transmission in such wireless networks, nodes can increase the message success rate by retransmitting messages. In broadcast communication without message acknowledgment, given an upper bound on the number of message retransmissions, reducing the number of retransmissions can improve broadcast efficiency. Simultaneously, piggybacking acknowledgments can reduce unnecessary retransmissions from other senders. Summary of the Invention

[0003] This invention relates to a multi-source reliable broadcast method for single-hop wireless networks based on piggybacked acknowledgments. The method is characterized by the presence of multiple broadcast source nodes in the network, each expecting to broadcast its message to all other nodes. Nodes use p-CSMA access to the wireless channel, and wireless links are susceptible to transmission collisions and random transmission losses. By piggybacking a field indicating whether other nodes have successfully transmitted a message a sufficient number of times when sending messages, unnecessary message retransmissions in the network are reduced, thus improving wireless broadcast efficiency. The main components include: a multi-source single-hop wireless network model and a method for calculating the number of reliable broadcast message retransmissions under multi-access shared channel conditions; a message structure and sending method with piggybacked acknowledgments; and a message receiving method based on piggybacked acknowledgments.

[0004] The proposed method addresses multi-broadcast source wireless single-hop network models and the calculation method for reliable broadcast message retransmission times under multi-access shared channel conditions, as follows:

[0005] Let G represent a single-hop wireless network consisting of N nodes, all operating on the same shared wireless channel. Each node is equipped with an omnidirectional antenna, and all nodes can communicate directly with each other, forming a single-hop wireless network. The MAC layer uses p-CSMA for channel access, where p is the channel access probability. Nodes lack collision detection capabilities, and during transmission, packet receivers do not directly acknowledge receipt. In a p-CSMA environment, packet transmission is susceptible to both transmission collisions and random transmission losses. Nodes employ multiple retransmissions to improve the success rate of single packet transmission. It is assumed that message reception success at different receiving nodes is independent of each other. In this patent, packets and messages are equivalent. Let S represent the set of broadcast source nodes. This patent considers multi-source broadcasting; therefore, |S|≥2.

[0006] Let ξ represent the probability of successful transmission, that is, the probability that a single source node sends a packet and all other N-1 nodes receive that packet. Let ε max This represents the maximum probability of packet transmission failure between all node pairs in a single-hop wireless network.

[0007] Without considering transmission collisions and only considering channel transmission loss, to achieve a given target transmission success probability ξ, such as ξ = 0.95, how many times does a packet need to be retransmitted under collision-free conditions? for:

[0008]

[0009] Considering both transmission collisions and random transmission losses, a sending node repeatedly sends a message x. t At this time, the probability that all N-1 other nodes successfully receive the message is:

[0010]

[0011] Where, p col =1-(1-p) N-1 It is the probability of a transmission collision occurring when a node sends a packet.

[0012] In order to achieve the target transmission success probability, i.e. p all ≥ξ, given N, p and ε max Based on the above formula, the minimum number of times x that a node needs to resend a message when there is a channel collision can be calculated. t .

[0013] The following further explains other components involved in this patent, including: the data structure of the message and related operations, and the message receiving and processing method based on piggyback confirmation.

[0014] 1) Message structure and sending method with piggyback acknowledgment

[0015] When each source node x∈S sends broadcast data packets, it uses a window mechanism to number the packets. Let k be the window size, such as k=8. Then the number of the packet to be sent must be an integer within the window range, i.e., 0 to k-1. Each message needs to carry the following information: the content of the message, the message number, and the current node's reception status of all messages currently being sent by other source nodes. For each other source node y∈S-{x}, the message reception status includes the following information: the number of the message that the current node x believes node y is currently sending, and whether x believes that the number of successfully received messages sent by y has been reached. The state is set to 1 if the destination is reached, and 0 otherwise. Based on this, each source node x sets the expected number of times each generated message will be sent to x. t Then, it begins sending the message;

[0016] 2) Message receiving method based on piggyback confirmation

[0017] • The processing steps for a normal node i∈V(G)-S receiving a message:

[0018] If the message is received for the first time, its content is stored locally; otherwise, the message is ignored.

[0019] • The processing steps for a broadcast source node x∈S receiving a message:

[0020] The message processing method is as follows: If the message is received for the first time, the message content is stored locally, and the successful reception count for this message is recorded as 1; if it is not the first time, further checks are performed: if the locally recorded successful reception count for this message has already reached... If the message is received twice, it is ignored; otherwise, the number of successful receptions of the message recorded locally is incremented by 1.

[0021] How to handle the part that includes confirmation:

[0022] (a) If the message number you are sending shown in the piggyback confirmation does not match the message number you are actually sending or preparing to send, ignore the confirmation; otherwise, proceed to the next step.

[0023] (b) If the status bit displayed in the ride confirmation is 0, ignore the confirmation; otherwise, proceed to the next step.

[0024] (c) When the status bit displayed in the piggyback confirmation is 1, the current node stops sending its current message and begins preparing to send the next message.

[0025] Thus, the multi-source broadcast method based on piggyback acknowledgment can effectively suppress excessive message retransmission in wireless single-hop networks.

Claims

1. A reliable multi-source broadcast method for wireless single-hop networks based on piggyback acknowledgment, characterized in that: In a single-hop wireless network, there are multiple broadcast source nodes, each with multiple messages to broadcast to all other nodes. All nodes operate on the same wireless channel and are equipped with omnidirectional antennas. Channel access uses the p-CSMA mechanism. Packet loss includes both transmission collisions and random transmission loss. By piggybacking confirmations of the number of times other source nodes have successfully sent messages when sending messages, unnecessary message retransmissions by other nodes are effectively suppressed, improving broadcast efficiency and channel utilization. The main components of this method include: a multi-broadcast source wireless single-hop network model and a method for calculating the number of reliable broadcast message retransmissions under multi-access shared channel conditions; a message structure and sending method with piggybacking confirmations; and a message receiving method based on piggybacking confirmations. This method addresses the multi-broadcast-source wireless single-hop network model and the reliable broadcast message retransmission count calculation method under multi-access shared channel conditions, as detailed below: Let G represent a single-hop wireless network consisting of N nodes, all operating on the same shared wireless channel. Each node is equipped with an omnidirectional antenna, and all nodes can communicate directly with each other, forming a single-hop wireless network. The MAC layer uses p-CSMA for channel access, where p is the channel access probability. Nodes do not have collision detection capabilities, and during transmission, the packet receiver does not directly acknowledge receipt. In the p-CSMA environment, packet loss can occur due to transmission collisions or random transmission loss. Nodes use multiple retransmissions to improve the success rate of single packet transmission. It is assumed that the success or failure of message reception at different receiving nodes is independent of each other. In this method description, packets and messages are equivalent. Let S represent the set of broadcast source nodes. This method considers multi-source broadcasting, therefore |S|≥2. Let ξ represent the probability of successful target transmission, that is, the probability that a single source node sends a packet and all other N-1 nodes receive that packet; let ε max This represents the maximum probability of packet transmission failure between all node pairs in a single-hop wireless network. Ignoring transmission collisions and considering only channel transmission loss, how many times does a packet need to be retransmitted under collision-free conditions to achieve a given target transmission success probability ξ? for: Considering both transmission collisions and random transmission losses, a sending node repeatedly sends a message x. t At this time, the lower bound of the probability that all N-1 other nodes have successfully received the message is: Where, p col =1-(1-p) N-1 It is the probability of a transmission collision occurring when a node sends a packet; In order to achieve the target transmission success probability, i.e. p all ≥ξ, given N, p and ε max Based on the above formula, the minimum number of times x that a node needs to resend a message when there is a channel collision can be calculated. t .

2. The reliable multi-source broadcast method for wireless single-hop networks based on piggyback acknowledgment according to claim 1, characterized in that: The message structure and sending method with piggyback acknowledgment, and the message receiving method based on piggyback acknowledgment, are detailed below: The message structure and sending method for attaching a confirmation are as follows: When each source node x∈S sends broadcast data packets, it uses a window mechanism to number the packets. Let k be the window size, then the number of the packet to be sent must be an integer within the window range, i.e., 0 to k-1. Each message needs to carry the following information: the message content, the message number, and the current node's reception status of all messages currently being sent by other source nodes. For each other source node y∈S-{x}, the message reception status includes the following information: the number of the message that the current node x believes node y is currently sending, and whether x believes that the number of successfully received messages sent by y has been reached. The state is set to 1 if the destination is reached, and 0 otherwise. Based on this, each source node x sets the expected number of times each generated message will be sent to x. t Then, it begins sending the message; The message receiving method based on piggyback confirmation is as follows: • The processing steps for a normal node i∈V(G)-S receiving a message: If the message is received for the first time, its content is stored locally; otherwise, the message is ignored. • The processing steps for a broadcast source node x∈S receiving a message: The message processing method is as follows: If the message is received for the first time, the message content is stored locally, and the successful reception count for this message is recorded as 1; if it is not the first time, further checks are performed: if the locally recorded successful reception count for this message has already reached... If the message is received successfully, it is ignored; otherwise, the local record of successful reception of the message is incremented by 1. The handling of piggybacked acknowledgments is as follows: (a) If the message number you are sending shown in the piggyback confirmation does not match the message number you are actually sending or preparing to send, ignore the confirmation; otherwise, proceed to the next step. (b) If the status bit displayed in the ride confirmation is 0, ignore the confirmation; otherwise, proceed to the next step. (c) When the status bit displayed in the piggyback confirmation is 1, the current node stops sending its current message and begins preparing to send the next message.

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