CN114245474A - Self-organizing time division multiple access method of automatic ship identification system - Google Patents
Self-organizing time division multiple access method of automatic ship identification system Download PDFInfo
- Publication number
- CN114245474A CN114245474A CN202111450444.1A CN202111450444A CN114245474A CN 114245474 A CN114245474 A CN 114245474A CN 202111450444 A CN202111450444 A CN 202111450444A CN 114245474 A CN114245474 A CN 114245474A
- Authority
- CN
- China
- Prior art keywords
- time slot
- time
- sending
- slots
- selecting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 30
- 230000005540 biological transmission Effects 0.000 claims description 7
- 238000010187 selection method Methods 0.000 claims description 7
- 230000014509 gene expression Effects 0.000 claims description 6
- 238000013507 mapping Methods 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 2
- 230000007547 defect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/08—Non-scheduled access, e.g. ALOHA
- H04W74/0833—Random access procedures, e.g. with 4-step access
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/08—Non-scheduled access, e.g. ALOHA
- H04W74/0833—Random access procedures, e.g. with 4-step access
- H04W74/0841—Random access procedures, e.g. with 4-step access with collision treatment
- H04W74/085—Random access procedures, e.g. with 4-step access with collision treatment collision avoidance
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Time-Division Multiplex Systems (AREA)
Abstract
The invention discloses a self-organizing time division multiple access method of an automatic ship identification system. The self-organizing time division multiple access method of the automatic identification system of the ship, which is provided by the invention, adds the feedback information of the time slot reservation conflict on the basis of the original SOTDMA protocol, so that the ship can adjust the time slot with conflict according to the feedback information, thereby reducing the time slot reservation conflict probability of the system. Compared with the prior access method, the invention reduces the interval of time slot selection, thereby reducing the time slot selection delay; in addition, the method can adjust the reserved time slot according to the conflict feedback information, thereby reducing the time slot reservation conflict rate, ensuring that the AIS system can still keep better safety performance under the condition of more users, and effectively improving the time slot utilization rate and the throughput of the channel.
Description
Technical Field
The invention relates to the technical field of ship communication, in particular to a self-organizing time division multiple access method of an automatic ship identification system.
Background
An Automatic Identification System (AIS) on board realizes the functions of channel Access and intercommunication between devices through Self-organized Time-Division Multiple Access (sodma) protocol. The SOTDMA channel access technique allows the AIS system to autonomously select a transmission time slot to transmit information based on the channel occupancy within a frame.
The tdma timeslot access protocol sets the duration of a frame of data to one minute (2250 timeslots, labeled 0-2249), and selects the timeslot generally according to the channel condition sensed in the previous frame (i.e. the previous minute) when each frame autonomously reserves the timeslot. When the time slot reservation conflict occurs, the method can not adjust the reserved time slot in order to avoid the time slot conflict, so that the conflict probability is higher under the condition of a large number of users, and the safety performance of the system under the condition of a crowded sea area is damaged.
Aiming at the defects of the time slot selection method, the invention designs a self-organizing time division multiple access method of an automatic ship identification system in order to effectively reduce the conflict probability and the time slot selection delay.
Disclosure of Invention
The invention aims to provide a self-organizing time division multiple access method of an automatic ship identification system, which adds feedback information of time slot reservation conflict on the basis of the original SOTDMA protocol, so that ships can adjust time slots with conflict according to the feedback information, and the time slot reservation conflict probability of the system is reduced.
The invention is implemented by the following technical scheme: a self-organizing time division multiple access method of an automatic ship identification system comprises the following steps:
step one, system initialization: starting a system, opening two paths of AIS receivers to respectively monitor two channels A and B for one minute, recording the information of each time slot of the two channels in the minute, and establishing a frame time slot state table of the channels A and B; confirming that the number of times of sending messages per minute of the ship is the report frequency, and recording the report frequency as Rr;
step two, network access: selecting an idle time slot as a first sending time slot by adopting a random access time division multiple access channel access mode according to the frame time slot state table obtained in the step one and taking the current time as the starting time; the first sending time slot is used for sending an AIS message type 3 report to the position of the first sending time slot, so that the first sending time slot can be perceived by other users in the network; after selecting an idle time slot, entering a third step; otherwise, continuing to adopt a random access time division multiple access channel access mode to select until finding an idle time slot;
step three, sending a first frame: according to the idle time slot selected in the step two as a first sending time slot, continuously dividing Rr sending time slots by using an incremental time division multiple access channel access mode and the frame time slot state table obtained in the step one, and sending an AIS message type 3 by using the Rr sending time slots; the system continues to monitor the information of the rest time slots in the frame, and updates the time slot state table according to the monitored information after the frame is finished, and then enters a fourth step;
step four, entering a continuous working mode: the system uses self-organizing time division multiple access method to send message when sending time slot comes; waiting for the arrival of a time slot and judging whether the current time slot is a sending time slot or not; if the current time slot is a sending time slot, entering the step five, otherwise, entering the step eight;
judging whether the time slot timeout value of the current sending time slot is 0 or not; if the time slot timeout value is 0, entering a sixth step, otherwise entering a seventh step;
step six, selecting a reserved time slot: the system uses time slot selection method and last updated frame time slot state table to reserve a new sending time slot for the next frame; if the reservation is successful, a new time slot timeout value is given to the new sending time slot, and a pair of mapping relations formed by the reserved new sending time slot and the current sending time slot is recorded in a local user time slot reservation information table; if the new time slot can not be reserved, the current time slot is taken as the reserved time slot, and a new time slot timeout value is given to the time slot; sending a message with reservation information in a self-organizing time division multiple access mode, and entering the ninth step;
step seven, if the time slot timeout value is not 0, the next frame still uses the current time slot to send information, the time slot timeout value count of the current time slot is reduced by 1, the updated information of the time slot timeout value is sent in a self-organizing time division multiple access mode, and then the step nine is entered;
step eight, receiving the information of the current time slot and analyzing the content of the information: if the current time slot receives the message with the reservation information sent by other users, recording the time slot reservation information into the time slot reservation information table of other users, and entering the ninth step;
step nine, judging whether the current frame is finished, namely judging whether the time slot number of the current time slot is 2249; if the time slot number of the time slot is less than 2249, it indicates that a frame is not finished, at this time, the step four is returned, otherwise, the step ten is entered;
step ten, comparing the reserved time slot of the user recorded in the local user time slot reservation information table in the frame with the reserved time slots of other users in the other user time slot reservation information tables, and judging whether a time slot reservation conflict occurs;
if a time slot reservation conflict occurs, the system gives up the time slot of the reservation conflict as the sending time slot of the next frame, uses the current sending time slot corresponding to the reserved time slot of the conflict as the sending time slot of the next frame according to the mapping relation formed by the reserved sending time slot and the current sending time slot in the time slot reservation information table of the local user, and sets the time slot timeout value as 1; if no slot reservation conflict occurs, the reserved slot is considered as a successful reservation.
Preferably, the timeslot selection method used in the sixth step is specifically:
step (1), obtaining system related parameters including report frequency of
Nominal starting time slot
And sending the information batch
The nominal starting time slot is the first sending time slot selected in the third step;
step (2) calculating a nominal time slot
Nominal increment of
And selecting the interval
The expression is shown as formula (1), formula (2) and formula (3):
wherein the nominal time slot
As the center of the time slot area for selectively sending the position report, the time slot area is a time slot number, the value range is 0-2249, and the nominal increment is
The number of time slots which are different between two adjacent nominal time slots and the interval are selected
Refers to a set of candidate slots for sending reports;
step (3), dividing the selection interval: will select the interval
At nominal time slot
Is divided into a left part and a right part for a boundary line, i.e.
And
selecting an interval
And selecting the interval
The expressions are shown in formula (4) and formula (5), respectively:
step (4) judging the current sending information batch
Parity of (A), if
When the number is odd, the interval is preferably selected
Selecting a time slot, and then entering the step (5); if it is
When even, it is preferable to select the interval
Selecting time slot internally, and entering the step (9);
step (5) selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (6); the idle time slot refers to a time slot which is not used in the receiving range of the AIS equipment, and a time slot which is marked to be occupied by other AIS equipment but has no message received in the time slot for three minutes;
step (6) in the selection interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, and entering the step (13) if the number of the time slots in the selectable time slot set is equal to 4; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is still less than 4, the step (7) is carried out;
step (7) of selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (8);
step (8) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set; if the number of time slots in the optional time slot set is equal to 4 or is within
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is more than 0, the step (13) is carried out; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is 0, the step (14) is carried out;
step (9) of selecting a selection interval
In which all time slots free on both channels are addedIf the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (10);
step (10) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, and entering the step (13) if the number of the time slots in the selectable time slot set is equal to 4; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is still less than 4, the step (11) is carried out;
step (11), selecting the selection interval
If the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (12);
step (12) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, if the number of the time slots in the selectable time slot set is equal to 4 or is within the range of 4
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is more than 0, the step (13) is carried out; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is 0, then the process is proceededEntering a step (14);
step (13), randomly selecting a time slot from the candidate time slot set as the next frame in the current nominal time slot
A lower transmission time slot;
step (14), if the current sending time slot is still available, continuing to use the current sending time slot; otherwise no time slot is reserved.
Preferably, in the third step, the holding flag in the communication state of the incremental tdma channel access mode is set to 1, and a corresponding time slot timeout value is generated for each transmission time slot, where the time slot timeout value is a random integer between 3 and 7.
Preferably, after the step ten, the method further includes updating the frame time slot state table according to the processed information of all reserved time slots, and clearing the local user time slot reservation information table and other user time slot reservation information tables; then step four is entered, and the slot information of the next frame is processed.
The invention has the advantages that:
compared with the existing access method, the self-organizing time division multiple access method of the automatic ship identification system provided by the invention has the advantages that the time slot selection interval is shortened, and the time slot selection delay is reduced; in addition, the method can adjust the reserved time slot according to the conflict feedback information, thereby reducing the time slot reservation conflict rate, ensuring that the AIS system can still keep better safety performance under the condition of more users, and effectively improving the time slot utilization rate and the throughput of the channel.
Description of the drawings:
in order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a time slot selection flowchart of a self-organizing time division multiple access method of an automatic ship identification system according to an embodiment of the present invention.
The specific implementation mode is as follows:
the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, a self-organizing time division multiple access method of an automatic ship identification system includes the following steps:
step one, system initialization: starting a system, opening two paths of AIS receivers to respectively monitor two channels A and B for one minute, recording the information of each time slot of the two channels in the minute, and establishing a frame time slot state table of the channels A and B; confirming that the number of times of sending messages per minute of the ship is the report frequency, and recording the report frequency as Rr;
step two, network access: selecting an idle time slot as a first sending time slot by adopting a random access time division multiple access channel access mode according to the frame time slot state table obtained in the step one and taking the current time as the starting time; the first sending time slot is used for sending an AIS message type 3 report to the position of the first sending time slot, so that the first sending time slot can be perceived by other users in the network; after selecting an idle time slot, entering a third step; otherwise, continuing to adopt a random access time division multiple access channel access mode to select until finding an idle time slot;
step three, sending a first frame: according to the idle time slot selected in the step two as a first sending time slot, continuously dividing Rr sending time slots by using an incremental time division multiple access channel access mode and the frame time slot state table obtained in the step one, and sending an AIS message type 3 by using the Rr sending time slots; the system continues to monitor the information of the rest time slots in the frame, and updates the time slot state table according to the monitored information after the frame is finished, and then enters a fourth step;
step four, entering a continuous working mode: the system uses self-organizing time division multiple access method to send message when sending time slot comes; waiting for the arrival of a time slot and judging whether the current time slot is a sending time slot or not; if the current time slot is a sending time slot, entering the step five, otherwise, entering the step eight;
judging whether the time slot timeout value of the current sending time slot is 0 or not; if the time slot timeout value is 0, entering a sixth step, otherwise entering a seventh step;
step six, selecting a reserved time slot: the system uses time slot selection method and last updated frame time slot state table to reserve a new sending time slot for the next frame; if the reservation is successful, a new time slot timeout value is given to the new sending time slot, and a pair of mapping relations formed by the reserved new sending time slot and the current sending time slot is recorded in a local user time slot reservation information table; if the new time slot can not be reserved, the current time slot is taken as the reserved time slot, and a new time slot timeout value is given to the time slot; sending a message with reservation information in a self-organizing time division multiple access mode, and entering the ninth step;
step seven, if the time slot timeout value is not 0, the next frame still uses the current time slot to send information, the time slot timeout value count of the current time slot is reduced by 1, the updated information of the time slot timeout value is sent in a self-organizing time division multiple access mode, and then the step nine is entered;
step eight, receiving the information of the current time slot and analyzing the content of the information: if the current time slot receives the message with the reservation information sent by other users, recording the time slot reservation information into the time slot reservation information table of other users, and entering the ninth step;
step nine, judging whether the current frame is finished, namely judging whether the time slot number of the current time slot is 2249; if the time slot number of the time slot is less than 2249, it indicates that a frame is not finished, at this time, the step four is returned, otherwise, the step ten is entered;
step ten, comparing the reserved time slot of the user recorded in the local user time slot reservation information table in the frame with the reserved time slots of other users in the other user time slot reservation information tables, and judging whether a time slot reservation conflict occurs;
if a time slot reservation conflict occurs, the system gives up the time slot of the reservation conflict as the sending time slot of the next frame, uses the current sending time slot corresponding to the reserved time slot of the conflict as the sending time slot of the next frame according to the mapping relation formed by the reserved sending time slot and the current sending time slot in the time slot reservation information table of the local user, and sets the time slot timeout value as 1; if no slot reservation conflict occurs, the reserved slot is considered as a successful reservation.
In this embodiment, the timeslot selection method used in the sixth step specifically includes:
step (1), obtaining system related parameters including report frequency of
Nominal starting time slot
And sending the information batch
The nominal starting time slot is the first sending time slot selected in the third step;
step (2) calculating a nominal time slot
Nominal increment of
And selecting the interval
The expression is shown as formula (1), formula (2) and formula (3):
wherein the nominal time slot
As the center of the time slot area for selectively sending the position report, the time slot area is a time slot number, the value range is 0-2249, and the nominal increment is
The number of time slots which are different between two adjacent nominal time slots and the interval are selected
Refers to a set of candidate slots for sending reports;
step (3), dividing the selection interval: will select the interval
At nominal time slot
Is divided into a left part and a right part for a boundary line, i.e.
And
selecting an interval
And selecting the interval
The expressions are shown in formula (4) and formula (5), respectively:
step (4) judging the current sending information batch
Parity of (A), if
When the number is odd, the interval is preferably selected
Selecting a time slot, and then entering the step (5); if it is
When even, it is preferable to select the interval
Selecting time slot internally, and entering the step (9);
step (5) selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (6); the idle time slot refers to a time slot which is not used in the receiving range of the AIS equipment, and a time slot which is marked to be occupied by other AIS equipment but has no message received in the time slot for three minutes;
step (6) in the selection interval
In and pressSelecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, and entering the step (13) if the number of the time slots in the selectable time slot set is equal to 4; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is still less than 4, the step (7) is carried out;
step (7) of selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (8);
step (8) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set; if the number of time slots in the optional time slot set is equal to 4 or is within
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is more than 0, the step (13) is carried out; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is 0, the step (14) is carried out;
step (9) of selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if optionalIf the number of the time slots in the slot set is less than 4, entering the step (10);
step (10) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, and entering the step (13) if the number of the time slots in the selectable time slot set is equal to 4; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is still less than 4, the step (11) is carried out;
step (11), selecting the selection interval
If the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (12);
step (12) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, if the number of the time slots in the selectable time slot set is equal to 4 or is within the range of 4
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is more than 0, the step (13) is carried out; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is 0, the step (14) is carried out;
step (13), randomly selecting a time slot from the candidate time slot setAt the current nominal time slot for the next frame
A lower transmission time slot;
step (14), if the current sending time slot is still available, continuing to use the current sending time slot; otherwise no time slot is reserved.
In this embodiment, the holding flag in the communication state of the incremental tdma channel access scheme in step three is set to 1, and a corresponding time slot timeout value is generated for each transmission time slot, where the time slot timeout value is a random integer between 3 and 7.
In this embodiment, the step ten is further followed by updating the frame slot state table according to the processed information of all reserved slots, and clearing the local user slot reservation information table and other user slot reservation information tables; then step four is entered, and the slot information of the next frame is processed.
Compared with the existing access method, the self-organizing time division multiple access method of the automatic ship identification system provided by the invention has the advantages that the time slot selection interval is shortened, and the time slot selection delay is reduced; in addition, the method can adjust the reserved time slot according to the conflict feedback information, thereby reducing the time slot reservation conflict rate, ensuring that the AIS system can still keep better safety performance under the condition of more users, and effectively improving the time slot utilization rate and the throughput of the channel.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (4)
1. A self-organizing time division multiple access method of an automatic ship identification system is characterized by comprising the following steps:
step one, system initialization: starting a system, opening two paths of AIS receivers to respectively monitor two channels A and B for one minute, recording the information of each time slot of the two channels in the minute, and establishing a frame time slot state table of the channels A and B; confirming that the number of times of sending messages per minute of the ship is the report frequency, and recording the report frequency as Rr;
step two, network access: selecting an idle time slot as a first sending time slot by adopting a random access time division multiple access channel access mode according to the frame time slot state table obtained in the step one and taking the current time as the starting time; the first sending time slot is used for sending an AIS message type 3 report to the position of the first sending time slot, so that the first sending time slot can be perceived by other users in the network; after selecting an idle time slot, entering a third step; otherwise, continuing to adopt a random access time division multiple access channel access mode to select until finding an idle time slot;
step three, sending a first frame: according to the idle time slot selected in the step two as a first sending time slot, continuously dividing Rr sending time slots by using an incremental time division multiple access channel access mode and the frame time slot state table obtained in the step one, and sending an AIS message type 3 by using the Rr sending time slots; the system continues to monitor the information of the rest time slots in the frame, and updates the time slot state table according to the monitored information after the frame is finished, and then enters a fourth step;
step four, entering a continuous working mode: the system uses self-organizing time division multiple access method to send message when sending time slot comes; waiting for the arrival of a time slot and judging whether the current time slot is a sending time slot or not; if the current time slot is a sending time slot, entering the step five, otherwise, entering the step eight;
judging whether the time slot timeout value of the current sending time slot is 0 or not; if the time slot timeout value is 0, entering a sixth step, otherwise entering a seventh step;
step six, selecting a reserved time slot: the system uses time slot selection method and last updated frame time slot state table to reserve a new sending time slot for the next frame; if the reservation is successful, a new time slot timeout value is given to the new sending time slot, and a pair of mapping relations formed by the reserved new sending time slot and the current sending time slot is recorded in a local user time slot reservation information table; if the new time slot can not be reserved, the current time slot is taken as the reserved time slot, and a new time slot timeout value is given to the time slot; sending a message with reservation information in a self-organizing time division multiple access mode, and entering the ninth step;
step seven, if the time slot timeout value is not 0, the next frame still uses the current time slot to send information, the time slot timeout value count of the current time slot is reduced by 1, the updated information of the time slot timeout value is sent in a self-organizing time division multiple access mode, and then the step nine is entered;
step eight, receiving the information of the current time slot and analyzing the content of the information: if the current time slot receives the message with the reservation information sent by other users, recording the time slot reservation information into the time slot reservation information table of other users, and entering the ninth step;
step nine, judging whether the current frame is finished, namely judging whether the time slot number of the current time slot is 2249; if the time slot number of the time slot is less than 2249, it indicates that a frame is not finished, at this time, the step four is returned, otherwise, the step ten is entered;
step ten, comparing the reserved time slot of the user recorded in the local user time slot reservation information table in the frame with the reserved time slots of other users in the other user time slot reservation information tables, and judging whether a time slot reservation conflict occurs;
if a time slot reservation conflict occurs, the system gives up the time slot of the reservation conflict as the sending time slot of the next frame, uses the current sending time slot corresponding to the reserved time slot of the conflict as the sending time slot of the next frame according to the mapping relation formed by the reserved sending time slot and the current sending time slot in the time slot reservation information table of the local user, and sets the time slot timeout value as 1; if no slot reservation conflict occurs, the reserved slot is considered as a successful reservation.
2. The self-organizing time division multiple access method of the automatic ship identification system according to claim 1, wherein the time slot selection method used in the sixth step is specifically:
step (1), obtaining system related parameters including report frequency of
Nominal starting time slot
And sending the information batch
The nominal starting time slot is the first sending time slot selected in the third step;
step (2) calculating a nominal time slot
Nominal increment of
And selecting the interval
The expression is shown as formula (1), formula (2) and formula (3):
wherein the nominal time slot
As the center of the time slot area for selectively sending the position report, the time slot area is a time slot number, the value range is 0-2249, and the nominal increment is
The number of time slots which are different between two adjacent nominal time slots and the interval are selected
Refers to a set of candidate slots for sending reports;
step (3), dividing the selection interval: will select the interval
At nominal time slot
Is divided into a left part and a right part for a boundary line, i.e.
And
selecting an interval
And selecting the interval
The expressions are shown in formula (4) and formula (5), respectively:
step (4) judging the current sending information batch
Parity of (A), if
When the number is odd, the interval is preferably selected
Selecting a time slot, and then entering the step (5); if it is
When even, it is preferable to select the interval
Selecting time slot internally, and entering the step (9);
step (5) selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (6); the idle time slot refers to a time slot which is not used in the receiving range of the AIS equipment, and a time slot which is marked to be occupied by other AIS equipment but has no message received in the time slot for three minutes;
step (6) in the selection interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, and entering the step (13) if the number of the time slots in the selectable time slot set is equal to 4; if at
After all time slot multiplexing rules are used, the number of time slots in the candidate time slot set is still less than 4, and then the process is carried outEntering a step (7);
step (7) of selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (8);
step (8) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set; if the number of time slots in the optional time slot set is equal to 4 or is within
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is more than 0, the step (13) is carried out; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is 0, the step (14) is carried out;
step (9) of selecting a selection interval
All idle time slots on two channels are added into a candidate time slot set, and if the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (10);
step (10) of selecting an interval
Priority order according to time slot multiplexing ruleSequentially selecting time slots and adding the time slots into the candidate time slot set, and entering the step (13) if the number of the time slots in the selectable time slot set is equal to 4; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is still less than 4, the step (11) is carried out;
step (11), selecting the selection interval
If the number of the time slots in the optional time slot set is more than or equal to 4, the step (13) is carried out; if the number of the time slots in the selectable time slot set is less than 4, entering the step (12);
step (12) of selecting an interval
Selecting time slots according to the priority order of the time slot multiplexing rule and adding the time slots into the candidate time slot set, if the number of the time slots in the selectable time slot set is equal to 4 or is within the range of 4
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is more than 0, the step (13) is carried out; if at
After all the time slot multiplexing rules are used, if the number of the time slots in the candidate time slot set is 0, the step (14) is carried out;
step (13), randomly selecting a time slot from the candidate time slot set as the next frame in the current nominal time slot
A lower transmission time slot;
step (14), if the current sending time slot is still available, continuing to use the current sending time slot; otherwise no time slot is reserved.
3. The ad-hoc tdma access method of an automatic ship identification system according to claim 1, wherein in said third step, a holding flag in said communication status of incremental tdma channel access mode is set to 1, and a corresponding time slot timeout value is generated for each transmission time slot, wherein the time slot timeout value is a random integer between 3 and 7.
4. The ad-hoc time division multiple access method of an automatic ship identification system according to claim 1, wherein the step ten is followed by updating the frame slot state table according to the processed information of all reserved slots, and emptying the local user slot reservation information table and other user slot reservation information tables; then step four is entered, and the slot information of the next frame is processed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111450444.1A CN114245474A (en) | 2021-12-01 | 2021-12-01 | Self-organizing time division multiple access method of automatic ship identification system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111450444.1A CN114245474A (en) | 2021-12-01 | 2021-12-01 | Self-organizing time division multiple access method of automatic ship identification system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114245474A true CN114245474A (en) | 2022-03-25 |
Family
ID=80752488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111450444.1A Pending CN114245474A (en) | 2021-12-01 | 2021-12-01 | Self-organizing time division multiple access method of automatic ship identification system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114245474A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115696448A (en) * | 2023-01-03 | 2023-02-03 | 成都实时技术股份有限公司 | AIS self-organizing time division multiple access network implementation method and device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113709899A (en) * | 2021-08-16 | 2021-11-26 | 杭州电子科技大学 | Self-organizing time division multiple access method of automatic ship identification system |
-
2021
- 2021-12-01 CN CN202111450444.1A patent/CN114245474A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113709899A (en) * | 2021-08-16 | 2021-11-26 | 杭州电子科技大学 | Self-organizing time division multiple access method of automatic ship identification system |
Non-Patent Citations (1)
| Title |
|---|
| 爱学习文库: "ITU-R M1371-5建议书", 《豆丁网》, pages 3 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115696448A (en) * | 2023-01-03 | 2023-02-03 | 成都实时技术股份有限公司 | AIS self-organizing time division multiple access network implementation method and device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11071093B2 (en) | Link adaption by channel bundling in a wireless communication system | |
| Zhao et al. | A dynamic queue protocol for multiaccess wireless networks with multipacket reception | |
| CA1242537A (en) | Multiple access communications system | |
| KR100772351B1 (en) | Method and apparatus for transmitting information within a communication system | |
| EP2489219B1 (en) | Coding methods and apparatus for broadcast channels | |
| CN111683350B (en) | Method for realizing shipborne VDES access protocol based on conflict feedback | |
| CN110611915B (en) | Method for self-adaptive control of self-organizing frequency hopping network frequency | |
| KR20090107031A (en) | Method of congestion management in a wireless mesh network | |
| EP2587855B1 (en) | Method and base station for adjusting carrier resources dynamically | |
| CN113709899B (en) | Self-organizing time division multiple access method for ship automatic identification system | |
| JP5391419B2 (en) | Wireless device and wireless communication system including the same | |
| CN112261678A (en) | Self-adaptive frequency hopping method and system suitable for ad hoc network | |
| CN102196587B (en) | Wireless-resource-dispatching method during multi-cell cooperation in relay-aided communication system | |
| CN114245474A (en) | Self-organizing time division multiple access method of automatic ship identification system | |
| Ma et al. | A novel contention-based MAC protocol with channel reservation for wireless LANs | |
| CN101755425B (en) | Method of managing transmission within a wireless communications network | |
| CN106879031A (en) | A kind of channel wireless radio multi Mesh network resource negotiation method based on double receipts single-shots | |
| JP2009124686A (en) | Method for multiple power-multiple access in wireless communication networks, and the network | |
| JP7339451B2 (en) | Resource allocation method, device and equipment | |
| CN102104517A (en) | Random number statement-based multiple access method | |
| KR20080098263A (en) | Communication method in ad-hoc network | |
| Fayaz et al. | Ez-channel: A distributed mac protocol for efficient channelization in wireless networks | |
| EP2555578A1 (en) | Wireless networks over frequency agil radio systems | |
| CN102413540A (en) | Self-organizing network unicast method with combination of cognitive network coding and routing based on cognition | |
| CN115208511A (en) | Configuration method and device of modulation and coding strategy and electronic equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |