A novel blocking network time slot allocation method

Abstract

The application discloses a novel time slot allocation method for block relay network, and belongs to the field of mobile ad hoc network. The application sets the reply confirmation time slot related to the data sending time slot for the reply confirmation message, and re-plans the time sequence of the whole network. In the block relay network adopting the TDMA scheme with N time slot space multiplexing, the request message and the data packet are sent from the source node, and are diffused outward hop by hop and time slot by time slot until reaching the destination node or naturally disappearing. The reply confirmation message is sent from the destination node, and is propagated to the source node hop by hop. However, since it is a reverse link, there are idle time slots in the propagation process, which is manifested as that all the nodes in the network "stop" for the transmission of effective information in some time slots. The application optimizes the transmission time sequence of the reply confirmation message, and designs a new sending time slot for the packet marked as the reply confirmation message, so that a forward path for the transmission hop by hop and time slot by time slot is simulated under the condition of not violating the basic premise of the TDMA protocol, and the utilization rate of resources is improved.

Description

Technical Field

[0001] This invention belongs to the field of mobile ad hoc networks and mainly relates to a novel time slot allocation method for relay networks. Background Technology

[0002] Mobile ad hoc networks (MANETs) are wireless, multi-hop, self-organizing mobile communication networks that do not rely on fixed infrastructure and can be rapidly deployed anytime, anywhere. Each node in the network is relatively independent yet possesses data reception and transmission capabilities; nodes can move freely, and the network topology dynamically changes; the high degree of cooperation between nodes and the distributed and parallel operation of nodes give the network high robustness and fault tolerance. MANETs have many advantages and were initially applied in the military field, but have since been widely used in environments such as field communications, rescue and disaster relief, and wireless sensor networks that operate outside of backbone networks.

[0003] Barrage Relay Networks (BRNs) are a novel ad hoc networking technology characterized by low latency, low overhead, and high reliability. BRNs are responsive, robust, and highly resilient mobile ad hoc networks that employ a time slot allocation scheme based on Time Division Multiple Access (TDMA) technology. They also possess good scalability and hold great potential for improving protocol models and optimizing network performance. BRNs utilize the blocking capabilities of some nodes to establish controlled interception zones. A controlled interception zone is a closed message area where forwarding of any information will not cross the zone's boundary, ensuring message reliability. Nodes within the controlled interception zone are classified into four types: source nodes, destination nodes, relay nodes, and blocking nodes. Nodes outside the controlled interception zone, not participating in message transmission, are called irrelevant nodes. When a source node sends information to a target node, it first sends and receives control messages. Intermediate nodes allocate time slots for sending tasks by receiving control messages from both the source and target nodes, determine their position in the network, and then determine their role in this communication task (relay node or blocking node), ultimately establishing a controlled interception zone. Once all nodes within the controlled interception zone have confirmed their identities, their processing methods for subsequent received messages are determined. Therefore, they can directly perform corresponding action-level processing (forwarding or discarding) on ​​received messages without needing to pass them to the upper layer, effectively improving the communication speed within the controlled interception zone. Summary of the Invention

[0004] The present invention aims to address the problem of resource waste caused by a large number of idle time slots in the existing time slot allocation scheme based on TDMA technology in relay networks; the present invention provides a novel time slot allocation method for relay networks.

[0005] The technical solution of this invention is a novel time slot allocation method for relay networks, which includes the following cyclic steps:

[0006] A. Request message stage;

[0007] B. Confirmation message stage;

[0008] C. Data transmission stage;

[0009] The request message stage:

[0010] (A1) Initialize nodes in the network to achieve clock synchronization; nodes with unicast stream transmission requirements send requests from the application layer to the lower layer to request a single unicast stream transmission; define the network lifetime TTL, the total number of time slots N, and start counting the time slot counter count.

[0011] (A2) The source node defines its own timeslot number T as 0; it sends a request message RTS containing timeslot T. The RTS message includes: message type declaration, unicast stream source-destination information, local node timeslot information, and hop count d from the source node. S-X Waiting for a confirmation message to arrive;

[0012] (A3) Ordinary nodes keep listening, unpack the first received request message, allocate their own data transmission time slot, and update the d in the message. S-X The field is incremented by 1; when the data transmission slot arrives, the updated request message is broadcast, and duplicate request messages are discarded; its own slot is determined by the first received request message. S-X Fields determined;

[0013] (A4) When the destination node receives the request message for the first time, it confirms that it is the destination node of the unicast stream, allocates its own data transmission time slot, and enters the confirmation message stage.

[0014] The confirmation message phase:

[0015] (B1) The destination node generates a Response Acknowledgment (CTS) message. The CTS message includes: message type, unicast stream source-destination information, and source-destination node hop distance d. S-D hop count d from the destination node X-D Broadcast CTS when the CTS time slot arrives;

[0016] (B2) Ordinary nodes keep listening, unpack the first received acknowledgment message, confirm their identity based on the hop count information in the received CTS message, and determine that a node that meets the judgment formula is a relay node, updating the d in the message. X-DThe field is incremented by 1, and a CTS message is broadcast when the next acknowledgment message slot arrives; nodes that do not meet the conditions are judged as blocking nodes and all subsequent packets are discarded; nodes that do not receive an acknowledgment message are judged as irrelevant nodes.

[0017] (B3) When the source node receives the reply confirmation message for the first time, it considers that the controlled interception area has been successfully established in this unicast stream transmission and can carry out unicast stream data transmission; it then enters the data transmission phase.

[0018] The data transmission phase:

[0019] (C1) If the node is the source node, it prepares to send a data packet and broadcasts the data packet when its own transmission time slot arrives, that is, when T = count % N;

[0020] (C2) If the node is a relay node and it is receiving this data packet for the first time, then it will forward the data packet when its own transmission time slot arrives, i.e., when T = count % N is satisfied; if a duplicate data packet is received, it will be discarded.

[0021] (C3) If the node is a blocking node, the node will discard the data packet directly after receiving it and will not forward it.

[0022] (C4) If the time slot count is less than the network lifetime TTL, repeat steps C1, C2, and C3; if the time slot count is greater than or equal to the network lifetime TTL, proceed to step C5.

[0023] (C5) All node types are changed to ordinary nodes, the time slot count is cleared to zero, and the node waits for the request message phase to arrive.

[0024] 1) Further, the method for calculating the transmission time slot in step A3 is as follows:

[0025] 2) T=(d s-x +1)%N

[0026] 3) Where % represents the remainder.

[0027] Furthermore, the CTS time slot in step B1 is calculated using the following formula:

[0028] 4)T CTS =(N+M-1-T)%N

[0029] Where M is any non-negative integer.

[0030] Furthermore, the decision formula in step B2 is:

[0031] 5)d S-X +d X-D ≤d S-D .

[0032] In this invention, by setting a reply acknowledgment time slot related to the data transmission time slot for the reply acknowledgment message, the overall network timing is redesigned. In a relay network using a TDMA scheme with N-slot spatial multiplexing, request messages and data packets both originate from the source node and propagate outward hop-by-hop and time-slot-by-time until they reach the destination node or naturally disappear. Reply acknowledgment messages, however, originate from the destination node and propagate hop-by-hop towards the source node. Because it is a reverse link, there are idle time slots during propagation, resulting in a "pause" in the transmission of valid information by all network nodes in certain time slots. This invention optimizes the transmission timing of reply acknowledgment messages by designing a new transmission time slot for packets marked as reply acknowledgment messages. Without violating the basic premises of the TDMA protocol, a forward path of hop-by-hop and time-slot-by-time transmission is simulated, improving resource utilization. Attached Figure Description

[0033] Figure 1 This is a timing diagram of the six-node chain network in this scheme. Detailed Implementation

[0034] To make the objectives, technical methods, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0035] like Figure 1 As shown, there are 6 nodes in the self-organizing network. In the mobile self-organizing network, the nodes are synchronized by default, and the time slot count is cleared after the network life cycle is completed.

[0036] The request message stage:

[0037] (A1) Node initialization in the network to achieve clock synchronization; Nodes with unicast stream transmission requirements send a request from the application layer to the lower layer to request a single unicast stream transmission; Define the network lifetime TTL, the total number of time slots N=3, the non-negative integer M=0, and start the time slot counting;

[0038] (A2) The source node defines its own timeslot number T as 0; it sends a request message (RTS) containing timeslot T. The RTS message includes: message type declaration, unicast stream source-destination information, local timeslot information, and hop count d from the source node. S-X Waiting for a confirmation message to arrive;

[0039] (A3) Ordinary nodes keep listening, unpack the first received request message, allocate their own data transmission time slot, and update the d in the message. S-X The field is incremented by 1; when the data transmission slot arrives, the updated request message is broadcast, and duplicate request messages are discarded; its own slot is determined by the first received request message. S-X The fields are determined, and the allocation algorithm is as follows: where % represents the remainder;

[0040] 6) T=(d s-x +1)%N

[0041] (A4) When the destination node receives the request message for the first time, it confirms that it is the destination node of the unicast stream, allocates its own data transmission time slot, and enters the confirmation message stage.

[0042] The confirmation message phase:

[0043] (B1) The destination node generates a response acknowledgment message (CTS). The CTS message includes: message type, unicast stream source-destination information, and source-destination node hop distance d. S-D hop count d from the destination node X-D ; broadcast an acknowledgment message when the acknowledgment message time slot arrives; allocate ordinary nodes by waiting for time slot allocation; the acknowledgment message time slot is defined by the allocated time slot:

[0044] (B2)T CTS =(N+M-1-T)%N

[0045] (B3) Ordinary nodes maintain listening, unpack the first received acknowledgment message, and confirm their own identity based on the hop count information in the received control message. The decision formula is as follows:

[0046] 7)d S-X +d X-D ≤d S-D

[0047] Nodes that meet the conditions are determined to be relay nodes, and the d value in the update message is updated. X-D The field is incremented by 1, and a CTS message is broadcast when the next acknowledgment message slot arrives. Nodes that do not meet the conditions are identified as blocking nodes and all subsequent packets are discarded. Nodes that do not receive an acknowledgment message are irrelevant nodes that are not related to this unicast stream transmission.

[0048] (B4) When the source node receives the reply confirmation message for the first time, it considers that the controlled interception area has been successfully established in this unicast stream transmission and can carry out unicast stream data transmission; it then enters the data transmission phase.

[0049] The data transmission phase:

[0050] (C1) If the node is the source node, it prepares to send a data packet and broadcasts the data packet when its own sending time slot arrives, that is, when T = count % 3.

[0051] (C2) If the node is a relay node and it is receiving this data packet for the first time, it will forward the data packet when its own transmission time slot arrives, i.e., when T = count % 3 is satisfied; if a duplicate data packet is received, it will be discarded.

[0052] (C3) If the node is a blocking node, the node will discard the data packet directly after receiving it and will not forward it.

[0053] (C4) If the time slot count is less than the network lifetime TTL, repeat steps C1, C2, and C3; if the time slot count is greater than or equal to the network lifetime TTL, proceed to step C5.

[0054] (C5) If all node types are changed to ordinary nodes, the time slot count is reset to zero, and the system waits for the request message phase to arrive.

[0055] The invention is characterized by:

[0056] Based on TDMA technology, a time slot allocation algorithm for spatial multiplexing of time slots is implemented, which enables nodes to make full use of channel resources for data transmission without causing competition for channel resources between nodes, thereby improving network transmission efficiency.

[0057] The request message phase assigns a time slot number that each node is allowed to send to. The acknowledgment message phase then simulates and plans a time slot-by-time propagation link sequence based on this. Through a more efficient request-acknowledgment interaction process, a link that can be used for message transmission is quickly established, overcoming the potential conflicts and congestion caused by high node density in broadcasting.

[0058] The time slot allocation scheme in this invention solves the topology change problem caused by node movement, dynamic joining and leaving in ad hoc networks by periodizing the three stages.

Claims

1. A novel time slot allocation method for relay networks, comprising the following iterative steps: A. Request message stage; B. Confirmation message stage; C. Data transmission stage; The request message stage: (A1) Initialize nodes in the network to achieve clock synchronization; nodes with unicast stream transmission requirements send requests from the application layer to the lower layer to request a single unicast stream transmission; define the network lifetime TTL, the total number of time slots N, and start counting the time slot counter count. (A2) The source node defines its own timeslot number T as 0; it sends a request message RTS containing timeslot T. The RTS message includes: message type declaration, unicast stream source-destination information, local timeslot information, and hop count d from the source node. S-X ; Waiting for a confirmation message to arrive; (A3) Ordinary nodes keep listening, unpack the first received request message, allocate their own data transmission time slot, and update the d in the message. S-X The field is incremented by 1; when the data transmission slot arrives, the updated request message is broadcast, and duplicate request messages are discarded; its own slot is determined by the first received request message. S-X Fields determined; The method for calculating the transmission time slot is: T = (d s-x +1)%N; Where % represents the remainder; (A4) When the destination node receives the request message for the first time, it confirms that it is the destination node of the unicast stream, allocates its own data transmission time slot, and enters the confirmation message stage; The confirmation message phase: (B1) The destination node generates a Response Acknowledgment (CTS) message. The CTS message includes: message type, unicast stream source-destination information, and source-destination node hop distance d. S-D hop count d from the destination node X-D Broadcast CTS when the CTS time slot arrives; CTS time slots are calculated using the following formula: T CTS = (N + M - 1 - T) % N; where M is any non-negative integer; (B2) Ordinary nodes keep listening, unpack the first received acknowledgment message, confirm their own identity based on the hop count information in the received CTS message, and determine that a node that meets the judgment formula is a relay node, updating the d in the message. X-D The field is incremented by 1, and a CTS message is broadcast when the next acknowledgment message slot arrives; nodes that do not meet the conditions are identified as blocking nodes and all subsequent packets are discarded. Nodes that do not receive an acknowledgment message are considered irrelevant nodes; (B3) When the source node receives the reply confirmation message for the first time, it considers that the controlled interception area has been successfully established in this unicast stream transmission and can carry out unicast stream data transmission; it then enters the data transmission phase. The data transmission phase: (C1) If the node is the source node, it prepares to send a data packet and broadcasts the data packet when its own transmission time slot arrives, that is, when T = count % N; (C2) If the node is a relay node and it is receiving this data packet for the first time, then it will forward the data packet when its own transmission time slot arrives, i.e., when T = count % N is satisfied; if a duplicate data packet is received, it will be discarded. (C3) If the node is a blocking node, the node will discard the data packet directly after receiving it and will not forward it. (C4) If the time slot count is less than the network lifetime TTL, repeat steps C1, C2, and C3; if the time slot count is greater than or equal to the network lifetime TTL, proceed to step C5. (C5) All node types are changed to ordinary nodes, the time slot count is cleared to zero, and the node waits for the request message phase to arrive.

2. The novel time slot allocation method for relay networks as described in claim 1, characterized in that, The decision formula in step B2 is: d S-X +d X-D ≤d S-D 。

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