JP2012227864A - Communication node - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress congestion and acceleration thereof appropriately with high accuracy without the significant change of the configuration, at a communication node where transmission or repeating of desired transmission information is carried out on a communication path in which the occupied band of each transmission section is common entirely or partially.SOLUTION: A communication node located on a communication path in which the occupied band of each transmission section is common entirely or partially includes a priority identification means for identifying the priority of the transmission information being transmitted to other communication node on the communication path or being repeated by other communication node, and a control means for setting the standby time preceding transmission of the transmission information based on the priority.

Description

  The present invention relates to a communication node that transmits and relays desired transmission information on a communication path in which the occupied band of each transmission section is common to all or a part thereof.

  Conventionally, a wireless communication system including a plurality of communication terminals is adjacent to wireless ad hoc network technology for constructing an inter-terminal communication network by autonomously determining a communication path in cooperation with adjacent terminals. By combining multi-hop communication technology that relays transmission information in multiple stages using terminals, various communication schemes that enable wireless transmission over a wide geographical area with small transmission power are applied.

  In addition, such communication methods can monitor environmental elements at many observation points by installing sensors that measure environmental elements such as water level, acceleration, rainfall, temperature, illuminance, etc. It is also applied to measurement control systems such as sensor network systems.

In addition, as prior art relevant to the present invention, there are technologies listed below.
(1) “Position fluctuations caused by the collapse of earth and sand are monitored by multiple terminals installed on the slope, and these terminals send anomaly detection information when a predetermined acceleration condition is detected and receive from other terminals. It is characterized by the fact that "flexibility and simplicity of installation of each terminal is ensured" by "collecting abnormality detection information at the highest terminal installed on the monitoring station side" Detection apparatus and method ... Patent Document 1

(2) “provided in a network system having a plurality of terminal devices that transmit and receive data and a communication line that connects these terminal devices to each other, and one terminal device in this network system transfers data to the communication line A network that determines whether or not the communication line is transferring data transmitted from another terminal device when transmitting, and if the data is being transferred, causes the one terminal device to wait for a predetermined time for data transmission In the communication control device, a frequency recognizing unit for recognizing the number of times that the one terminal device waits for data transmission within a predetermined time, a tolerance storage unit for storing a preset allowable number of standby times, and the frequency recognizing unit The number of times recognized by the means is compared with the number of allowable standby times stored by the tolerance value storage means, and if the number of times recognized by the frequency recognition means is greater, the communication line And an overload determining means for determining that the data is in an overload state, and a time changing means for changing the predetermined time so that the waiting time for data transmission is increased when the overload determining means determines that the overload state is present. Thus, a network communication control device characterized by “determining the back-off time according to the line status such as the transmission avoidance frequency or the number of retransmission attempts”.

(3) "In a satellite communication system comprising a satellite and one central station and a plurality of peripheral stations that communicate via the satellite, the peripheral station transmits a data on a time slot as a header. Means for adding the number of data transmission attempts, the central station monitors the presence or absence of normal data reception in each time slot, notifies the peripheral station of data reception confirmation, and receives the data received within a predetermined time Means for judging the traffic state from the number and the sum of the number of transmission attempts and broadcasting the information notifying the traffic state to the peripheral station, and the peripheral station confirms reception from the central station. By including the means for retransmitting the data that was not received and generating a random number at that time and determining the waiting time until the re-transmission. A satellite communication system characterized in that the back-off time is determined according to the line status such as the number of retransmission attempts.

(4) “In the case where communication between the master unit and the slave unit is performed by radio waves, the slave unit includes a transmission means, a reception means, and a return confirmation means for confirming a return from the master unit. A retransmission timer, a retransmission means for retransmitting after a time determined by the retransmission timer if the reply from the master cannot be confirmed by the return confirmation means after transmission by the transmission means, and a number of retransmissions A retransmission counter that counts, and the retransmission timer includes a retransmission time setting unit that changes a value set according to the value of the retransmission counter. Wireless communication device characterized in that "the setting is made" ... Patent Document 4

JP 2006-98128 A JP-A-10-56470 JP-A-6-252917 JP 2005-94429 A

  By the way, the above-described collapse detection apparatus and method require that the information arrival time until the abnormality detection information reaches the highest terminal is short in order for the system administrator to perform a quick response when the abnormality is detected. In order for the terminal to be installed in a place where a power source is not installed, it is possible to drive the battery by battery or natural energy power generation, and the power saving of the terminal is strictly required.

  However, for example, when a synchronous communication method corresponding to a beacon signal is applied between terminals, the beacon signal must be transmitted at a short cycle interval in order to shorten the information arrival time, and is normal. Even at times, frequent repetition of transmission is required, and it becomes difficult to save power. Therefore, an asynchronous communication method may have to be adopted instead of the synchronous communication method.

However, when an asynchronous communication method is applied between terminals, when a plurality of terminals transmit asynchronously, in order to avoid loss of transmission information due to congestion of transmission signals of these terminals, for example, CSMA / CA (Carrier Sense Multiple
In some cases, the “Access / Collision Avoidance” method was also adopted.

  However, in such a CSMA / CA system, transmission is performed to avoid congestion of the transmission signal when it is confirmed that the corresponding radio channel is free under carrier sense performed prior to transmission. The longer the back-off time that should be waited before the transmission time, the more effectively the transmission rate of transmission information becomes slower.

Note that such a delay in transmission speed is improved in the above-described network communication control device, satellite communication system, and wireless communication device.
However, the setting of the back-off time performed in these network communication control devices and satellite communication systems cannot be expected to have an immediate effect due to the restrictions listed below, and may be difficult to realize with simple processing.

(1) In order to obtain an appropriate backoff time, the retransmission must be repeated multiple times.
(2) In a system such as a disaster monitoring system where there is a large difference in traffic between normal times and when a disaster occurs, or between a small disaster and a large-scale disaster, the traffic is determined based on the past transmission standby frequency, the number of retransmissions, etc. In order to be predicted, it is necessary to statistically grasp the transition of traffic.

  Further, in the above-described wireless communication apparatus, the maximum back-off time is set longer according to the number of terminals. Therefore, when the transmission frequency is low even if the number of terminals is large, the back-off time is averaged. The time is set unnecessarily long, and the delay in the transmission speed cannot be shortened effectively and accurately.

  However, especially in disaster monitoring systems such as river flooding and landslides, environmental factors may change continuously, and terminals installed in a wide geographical area may repeatedly attempt to transmit observation results all at once. Therefore, there is a strong demand for a technology that can stably and accurately maintain the real-time performance and reliability of disaster monitoring because traffic is concentrated on a large number of communication paths and increases in a short time.

  An object of the present invention is to provide a communication node that can accurately and appropriately suppress congestion and acceleration of congestion without a significant change in configuration.

  In the first aspect of the present invention, in the communication node arranged on the communication path where the occupied band of each transmission section is common in the whole area or in part, the priority identification means is the other arranged on the communication path. The priority of the transmission information to be transmitted to the other communication node or to be relayed by the other communication node is identified. The control means sets a time to be waited prior to transmission of the transmission information based on the priority.

  That is, since the time to wait before transmission is set based on the priority of transmission information to be transmitted through the communication path, the processing amount required for the setting and the priority are Both of the possibility that transmission of high transmission information is unnecessarily delayed will be kept low.

  According to a second aspect of the present invention, in the communication node according to the first aspect, the control means sets the time by weighting with a random number generated according to the time when the transmission information is obtained or the content of the transmission information. obtain.

  That is, the time point at which transmission is performed after the elapse of the time is set based on the priority of transmission information to be transmitted via the communication path, but weighting by the random number is performed even if the priority is the same. Is distributed on the time axis.

  In the invention according to claim 3, in the communication node according to claim 1 or claim 2, the control means reduces the time as the number of communication nodes adjacent to the communication node on the communication path decreases. Set it short.

  In other words, the lower the possibility of congestion between adjacent communication nodes on the communication path, the shorter the transmission delay due to the collision, and the shorter the time required to recover the transmission delay. .

  According to a fourth aspect of the present invention, in the communication node according to any one of the first to third aspects, the control means is the number of communication nodes that should relay the transmission information on the communication path. The larger the is, the shorter the time is set.

  In other words, the greater the number of relays (number of hops) that are performed in order to transmit the transmission information to the desired destination on the communication path, the shorter the transmission delay due to collision that may occur in each transmission section on the communication path. And a long time required to recover the transmission delay is secured.

  According to a fifth aspect of the present invention, in the communication node according to any one of the first to fourth aspects, the priority identifying means sets the priority to the other information prior to the transmission information. The transmission information transmitted to the communication node and the transmission information relayed by the other communication node are identified as smoothing values of the priority of either or either one.

  In other words, transmission information to be transmitted or relayed in chronological order has a transmission capacity even if the frequency of events in which the priority of these transmission information increases rapidly decreases or decreases while increasing or decreasing. Are distributed high on average.

According to the present invention, the transmission capacity of each transmission section on the communication path is appropriately distributed to transmission information with a wide range of priorities to be transmitted and relayed without greatly complicating the configuration.
Further, according to the present invention, it is possible to flexibly adapt to various arrangements of communication nodes on the communication path.

Furthermore, according to the present invention, it is possible to flexibly adapt to the frequency and form in which transmission information requiring certainty is to be transmitted or relayed.
Therefore, in the communication system and the transmission system to which the present invention is applied, the overall transmission quality and reliability are improved at a low cost and are maintained stably.

It is a figure which shows one Embodiment of this invention. It is an operation | movement flowchart of the processor in this embodiment. It is a figure which supplements operation | movement of this embodiment. It is a figure which supplements the calculation method of the back-off time applicable to this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.
In the figure, this embodiment is configured as a river water level monitoring system, and terminals 10-1 to 10-6 are respectively installed at six sites provided along the river 11, and the terminal 10-7 is downstream of the river 11. Or it is arrange | positioned in the monitoring station building 12 located in the site near a river mouth.

The terminal 10-1 includes the following elements.
(1) Sensor 10S-1 used for detection and measurement of predetermined items
(2) Processor 10P-1 having an input port connected to the output of sensor 10S-1
(3) Radio transceiver 10RF-1 connected to a specific input / output port of processor 10P-1
(4) Antenna 10A-1 in which a feeding point is connected to the antenna terminal of the wireless transceiver 10RF-1

  Here, since the configurations of the terminals 10-2 to 10-7 are the same as the configuration of the terminal 10-1, the description thereof will be omitted here. The same reference numerals with “2” to “7” added in place of them are given.

Further, in the following, for items common to all of the terminals 10-1 to 10-6, any of these suffix numbers “1” to “6” is used instead of the suffix numbers “1” to “6”. A suffix “c” indicating that it can be applied is added to the code of the corresponding component to describe.
The terminal 10-7 is different from the terminals 10-1 to 10-6 in that no sensor corresponding to the sensor 10S-1 described above is provided.

FIG. 2 is an operation flowchart of the processor in this embodiment.
FIG. 3 is a diagram supplementing the operation of the present embodiment.
The operation of this embodiment will be described below with reference to FIGS.

[Basic operation by cooperation of each part]
In the present embodiment, terminals 10-1 to 10-7 are formed with a multi-hop communication system composed of the following three communication paths as shown by dotted lines in FIG.

(1) First communication path formed in the section from terminal 10-1 to terminal 10-6 via terminal 10-3 and terminal 10-5
(2) Second communication path formed in the section from terminal 10-2 to terminal 10-6 via terminal 10-4
(3) Third communication path formed between the terminal 10-6 and the terminal 10-7

  In addition, in each transmission section of the first to third communication paths, a radio channel having the same radio frequency and occupied band is shared, and is included in a packet of a predetermined format and corresponds to a destination of transmission information. An address communication method based on a unique address indicating a terminal (adjacent on the corresponding communication path) is applied. Note that a common modulation scheme and multiple access scheme do not necessarily have to be applied to the wireless channels shared in this way.

  In the terminal 10-c, the processor 10P-c monitors the water level of the river 18 measured by the sensor 10s-c or an increase in the water level at a predetermined frequency, and the water level or the increase exceeds a predetermined threshold value. Then, “abnormality detection information” indicating that is generated. Such abnormality detection information includes, for example, a water level, a water level change value, an occurrence time, and the like.

  Further, the processor 10P-c is referred to as a terminal 10-7 or a terminal adjacent to the terminal 10-7 in a direction close to the terminal 10-7 on a communication path in which the terminal 10-c is incorporated as a communication node (hereinafter referred to as “upper terminal”). ), The abnormality detection information is transmitted via the wireless transmission / reception unit 10RF-c and the antenna 10A-c.

  Further, in the terminal 10-c, the processor 10P-c is a terminal adjacent to the terminal 10-7 on the communication path in which the terminal 10-c is incorporated as a communication node (hereinafter referred to as “lower terminal”). )) And transmission information such as abnormality detection information delivered from any of the above-described host terminals is acquired via the antenna 10A-c and the wireless transmission / reception unit 10RF-c.

  Further, the processor 10P-c notifies the terminal (hereinafter referred to as “downstream terminal”) adjacent to the terminal via the transmission section that follows the communication path, via the radio transmission / reception unit 10RF-c and the antenna 10A-c. By transmitting detection information, the corresponding transmission information is relayed.

  The terminal 10-7 collects anomaly detection information transmitted from any of the terminals 10-1 to 10-6 in this way and performs aggregation, and performs processing suitable for the result of the aggregation (for example, corresponding anomaly detection) Information display and notification to a higher-level observation station or system administrator (not shown).

  In the present embodiment, for example, as indicated by a dotted frame in FIG. 1, a terminal 10 to which a radio signal transmitted to a terminal 10-6 adjacent to the terminal 10-4 is applied with a common radio frequency and occupied band is applied. -5 also arrives at a predetermined level, and at the same time as the radio signal, the terminal 10-5 similarly attempts to transmit any radio signal addressed to the adjacent terminal 10-6. As shown in FIG. 3, 10-5 and 10-6 obtain the transmission right sequentially while avoiding congestion on the physical radio channel by performing the following linkage.

(1) The terminal 10-4 (processor 10P-4) identifies that a carrier signal is not detected in the corresponding radio channel based on the carrier sense CS (FIG. 3 (1)), and then transmits a transmission request RTS (Request to By transmitting (Send) (FIG. 3 (2)), a predetermined wireless packet is transmitted.
(2) On the other hand, the terminal 10-5 (processor 10P-5) similarly determines whether or not transmission to the corresponding radio channel is possible (a carrier signal is detected) based on the carrier sense CS ( In FIG. 3 (3), since the wireless packet (or some carrier signal) has already been transmitted to the wireless channel by the terminal 10-4, transmission is suspended (FIG. 3 (4)).

(3) Upon receiving the wireless packet transmitted by the terminal 10-4, the terminal 10-6 (processor 10P-6) transmits a wireless packet indicating reception ready completion CTS (Clear to Send) (FIG. 3 ( Five)).
(4) The terminal 10-4 (processor 10P-4) responds to the radio packet transmitted by the terminal 10-6 (processor 10P-6) in this manner, and then the terminal 10-6 (processor 10P-6). Identifies that the preparation for reception has been completed (FIG. 3 (6)), and sends desired transmission information as a wireless packet to the terminal 10-6 via the corresponding wireless channel (FIG. 3 (7)).

(5) On the other hand, the terminal 10-5 (processor 10P-5) is in a state in which no terminal is transmitting to the corresponding wireless channel when the transmission of all the wireless packets is completed. When such a state is identified, it is linked in the same manner as the terminal 10-6 (processor 10P-6) instead of the terminal 10-4 (processor 10P-4) (FIG. 3 (2) ', (5 ) ′, (6) ′, (7) ′), the desired transmission information is transmitted to the terminal 10-1.

  The feature of the present invention is that, in this embodiment, the processor 10P-c provided in the terminal 10-c precedes the transmission information transmission (including the transmission accompanying the above-described relay) to the upper terminal described above. The back-off time W indicating the time to be waited for is obtained as follows.

(1) The difference V (= ΔL−th) between the change amount ΔL of the water level L measured by the sensor 10S-c and the predetermined threshold th is obtained as an “abnormal evaluation value” (step S1 in FIG. 2).
(2) Generate a random number Rnd (0 <Rnd ≦ 1) (step S2 in FIG. 2).

(3) Time T (here, assumed to be constant) occupied for transmission of abnormality detection information, a predetermined count α, and the random number Rnd Then, a back-off time W (which is an integral multiple of the time T) expressed by the following equation is calculated for the function ceil () indicating the rounding-down operation below the decimal point (step S3 in FIG. 2).
W = T · ceil (α · V · Rnd) (a)

  The processor 10P-c applies the back-off time W calculated in this way as follows, so that the transmission information that is the target of transmission to the upper terminal (including transmission for relay) corresponds. Reduce the possibility of collisions in subsequent sections of the route.

(1) Under the above-described relationship facing the carrier sense or the downstream terminal, there is no transmission by other terminals located around the terminal 10-c and the host terminal can receive the signal. If this is confirmed, transmission of the corresponding abnormality detection information is tried (step S4 in FIG. 2).

(2) If the transmission is not possible, the transmission is postponed, and after waiting for the back-off time W, the postponed transmission is retried (step S5 in FIG. 2).

(3) If the “ACK response” returned by the upper terminal cannot be received after transmitting the abnormality detection information, the corresponding transmission is performed after waiting for the back-off time W, as in the case where the above transmission is matched. Is retried (step S6 in FIG. 2).

  When transmission to the upper terminal is performed asynchronously in each transmission section on the communication path, a standby for the back-off time W is performed only before retrying transmission that was not normally completed. May be.

  By the way, for the back-off time W, as listed below, the unit of the abnormality evaluation value V, the value of the coefficient α, and the like are set to values suitable for the application.

(1) When T = 100 ms, α = 1, and V = 5 cm, the back-off time W has a maximum value and a minimum value of 500 ms and 100 ms, respectively, and is a time that randomly changes in five steps in units of 100 ms. It becomes.

(2) The following formula (b) including the number N of terminals adjacent to the destination terminal including its own terminal is applied in place of the above-described formula (a). Time W is set longer.
W = T · ceil (α · V · N · Rnd) (b)

(3) The following equation (c) including the number B of terminals (the highest terminal may not be included) placed on the corresponding communication path is applied instead of the above-described equation (a). Thus, the larger the number B, the longer the back-off time W is set, and the promotion of the congestion on the upstream side on the communication path is promoted. W = T · ceil (α · V · (B + 1) · Rnd) ... (c)

(4) Instead of the abnormality evaluation value V, the “abnormality evaluation peak hold value” obtained by smoothing (integrating) the maximum value of the abnormality evaluation value V is applied to the above-described equations (a) to (c). By doing so, for example, even when the abnormal evaluation value V is suddenly decreased, the back-off time W is avoided from being shortened rapidly, and further, for example, calmly calmed down, such as a river increase. Such a flexible adaptation of the back-off time W is possible even in various applications for detecting events in which traffic changes gently, such as natural disasters.

(5) Instead of the abnormality evaluation value V, the “abnormality evaluation peak hold value” obtained by smoothing (integrating) the maximum value of the abnormality evaluation value V is applied to the above-described equations (a) to (c). However, as shown in FIG. 4, the maximum value is the maximum value of the abnormality evaluation value V set in advance when a predetermined time equal to or longer than the back-off time W elapses from the time of update. By suspending the update until the time exceeds, flexible adaptability to the actual occurrence and progress of the desired natural disaster is ensured.

  That is, it is expected that the amount of information transmission of the entire system is already large or will increase soon as the abnormality evaluation value V indicating the possibility of a disaster and the scale of a disaster that has occurred, such as the rate of increase in water level, is large. In a situation where there is a high possibility that the back-off time w is high, the back-off time w is set so as to decrease gradually with the passage of time.

Therefore, according to the present embodiment, the processing performed by the processor 10P-c is not significantly changed or complicated, and any of the following items can be avoided, and congestion avoidance and transmission efficiency can be balanced. At the same time, flexible and optimal transmission capacity is widely distributed.
(1) Unnecessarily long backoff time should be set
(2) Useless retransmissions and congestion until the optimal backoff time is set
(3) Unnecessary retransmission and congestion when a sudden change in detection event occurs

  The present invention is not limited to the river water level monitoring system described above. For example, various measurement control systems in which each terminal is linked to a sensor that measures a desired environmental element such as a water level, acceleration, rainfall, temperature, and illuminance. The same applies to the above.

  In addition, the present invention can be similarly applied to a monitoring system that issues an alarm by predicting the occurrence of a natural disaster such as a landslide under the combination of the above environmental elements.

  Furthermore, the present invention is not limited to monitoring natural phenomena, but may be a system that can infer a trend of increase or decrease in the transmission amount of the entire system from the monitoring status of a specific location, such as road traffic volume or gas or water usage. It is equally applicable.

  In the present invention, the calculation of the back-off time W includes the above-described abnormality evaluation value V, the count α, the random number Rnd, the number N of adjacent terminals, the number B of terminals performing relay processing, and the average value of peak values. As long as it is suitable for the essence of measured values transmitted as transmission information and the form of actual changes, and can reduce unnecessary congestion and increase in transmission capacity associated with transmission and relay of the transmission information, any physical quantity or Attributes may be applied.

  Furthermore, in the present embodiment, the configuration of the first to third communication paths described above may be any.

  In the present embodiment, any frequency arrangement, modulation scheme, multiple access scheme, and channel can be used for the first to third communication paths as long as the above-described effects are obtained under the backoff time W. A control method may be applied.

  Furthermore, the present invention is not limited to a multi-hop communication system in which wireless transmission is performed, and can be applied to, for example, a transmission system formed in a star shape and an ad hoc multi-hop communication system.

  The present invention is also applicable to a communication system formed on a metallic transmission line or an optical transmission line if a communication path in which a desired terminal intervenes as a communication node is formed by address communication between these terminals. Applicable.

  Further, the present invention is not limited to the above-described embodiments, and various configurations can be made within the scope of the present invention, and any improvement may be applied to all or some of the components.

  Hereinafter, among the inventions disclosed in the present application, the configurations, operations, and effects of the invention not described in “Claims” are described in the “Claims” and “Means for Solving the Problems” column. Use a format that conforms to

[Claim 6] In the communication node according to claim 1 or 2,
The control means includes
The communication node is characterized in that the time is set shorter as the number of communication nodes adjacent to the communication node on the communication path is larger.

  In the communication node having such a configuration, the waiting time prior to transmission becomes shorter on average than the communication node according to the third aspect, and transmission can be performed with priority over other nodes.

  Therefore, the present invention is suitable for application to a communication node that requires quick information collection.

[Claim 7] In the communication node according to any one of claims 1 to 3 and claim 6,
The control means includes
The communication node is characterized in that the time is set shorter as the number of communication nodes that should relay the transmission information on the communication path is smaller.

  In the communication node having such a configuration, the waiting time prior to transmission becomes shorter on average than the communication node according to the fourth aspect, and transmission can be performed with priority over other nodes.

  Therefore, the present invention is suitable for application to a communication node that requires quick information collection.

  The communication node according to the present invention is applied, for example, by selecting and applying the invention according to any one of claims 6 and 3 according to the priority, or similarly depending on the priority. By selecting and applying the invention according to any one of claims 7 and 4, it is possible to quickly and preferentially transmit transmission information with high priority.

[Claim 8] In the communication node according to claim 5,
The priority identifying means includes
The communication node, wherein the smoothing value is obtained based on an exponential smoothing method or a moving average method.

  In the communication node having such a configuration, in the communication node according to claim 5, the priority identifying unit obtains the smoothed value based on an exponential smoothing method or a moving average method.

  That is, transmission information to be transmitted and relayed in chronological order is relatively low even if the frequency of events in which the priority of these transmission information becomes high decreases rapidly or decreases. Under a large weighting of the priority of new transmission information, the transmission capacity is distributed high on average.

  Therefore, it is possible to flexibly adapt to the frequency and form of transmission information that requires urgent transmission or relay.

10 terminal 10P processor 10RF wireless transmission / reception unit 10S sensor 11 river 12 monitoring station building

Claims (5)

A communication node arranged on a communication path in which the occupied band of each transmission section is common in the whole area or in part,
Priority identification means for identifying the priority of transmission information to be transmitted to another communication node arranged on the communication path or to be relayed by the other communication node;
And a control means for setting a time to be waited prior to transmission of the transmission information based on the priority. The communication node according to claim 1,
The control means includes
The communication node characterized in that the time is obtained by weighting with a random number generated when the transmission information is obtained or according to the content of the transmission information. In the communication node according to claim 1 or 2,
The control means includes
The communication node is characterized in that the time is set shorter as the number of communication nodes adjacent to the communication node on the communication path is smaller. The communication node according to any one of claims 1 to 3,
The control means includes
The communication node is characterized in that the time is set shorter as the number of communication nodes that should relay the transmission information on the communication path is larger. In the communication node according to any one of claims 1 to 4,
The priority identifying means includes
The priority is a smoothing value of the priority of either or either of the transmission information transmitted to the other communication node prior to the transmission information and the transmission information relayed by the other communication node. A communication node characterized by being identified as