JP2012209972A - Communication device, communication method, and communication program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable use of a carrier sense level optimal for an intermittent operation and flexible adjustment of the carrier sense level when performing a reception operation intermittently for a predetermined period.SOLUTION: A communication device includes radio communication means having a carrier sense part, transmission control means, reception control means, and carrier sense switching means for switching a carrier sense level of the carrier sense part to a level at receiving a packet. Further, the transmission control means causes start-request packets to be continually transmitted incessantly at transmission of a data packet, and causes the data packet to be transmitted after receiving a start-response packet; the carrier sense part intermittently performs plural times of carrier sense for a predetermined period; the reception control means, having received a start-request packet within a predetermined reception period after starting with the intermittent carrier sense, causes a transmission destination to respond with a start-response packet and stands by to receive data.

Description

  The present invention relates to a communication device, a communication method, and a communication program. For example, the present invention is applied to a communication device, method, and program in which a large number of wireless communication nodes distributed in a space such as a sensor network perform data communication with each other using wireless communication. It is possible.

  For example, nodes constituting a communication system such as a sensor network are required to save power.

  Non-Patent Document 1 describes a technique in which a wireless device performs communication while performing an intermittent activation operation (hereinafter also referred to as an intermittent operation). FIG. 2 is an explanatory diagram illustrating the technology described in Non-Patent Document 1.

  As shown in FIG. 2, the technology described in Non-Patent Document 1 turns on the wireless device for a short time every predetermined period T and waits for reception, and turns off the power supply during other periods. This is intended to save power. Hereinafter, this periodic reception standby timing is referred to as “sniff timing”.

  In FIG. 2, in order to transmit a data packet from the transmission node A to the reception node B, the transmission node A needs to transmit in accordance with the sniff timing of the reception node B. It is difficult to know the sniff timing.

  Therefore, as shown in FIG. 2, when traffic occurs, the transmission node A continuously transmits activation request packets. By doing so, the activation request packet can be given during the sniff timing period of the receiving node B which is the destination.

  Thereafter, the receiving node B returns a start response packet to the transmitting node A, so that the transmitting node A can know that the receiving node B which is the transmission destination is in a reception standby state, and transmits the data packet correctly. be able to.

The technique described in Non-Patent Document 1 is called “power saving listening”, which is a very simple method and a method that can expect a power saving effect.
En-Yi A. Lin, Jan, M. Rabaey, Adam Wolisz, “Power-Efficient Rendez-Vous Shemes for Dense Wireless Sensor Networks”, IEEE International Conference on Communications 2004.

  The technology described in Non-Patent Document 1 can be expected to further improve the power saving effect as the reception standby time at the sniff timing is shortened.

  On the other hand, if the reception waiting time is too short, only a part of the transmitted activation request packet can be received as shown in FIG. 3, and the activation request packet from another node may be missed.

  At this time, the activation request packet cannot be received, but a part of the packet has been received, so the received power intensity is a high value.

  Therefore, as a method of solving the problem by using this, if the default reception standby time is shortened, carrier sensing is performed continuously after the reception standby time, and the state where the reception power intensity is high continues, the reception standby time There is a method of extending (see FIG. 3). As a result, since the reception waiting time can be extended, the activation request packet can be received.

  Here, the reference level for determining whether the received power intensity is high or low is referred to as “carrier sense level”. This carrier sense level is a parameter related to a collision avoidance method such as CSMA (Carrier Sense Multiple Access) performed at the time of packet transmission. Generally, the carrier sense level value takes into consideration that packet transmission does not interfere with other systems. Is decided.

  Therefore, it is an appropriate value for avoiding a collision by CSMA or the like, but it is an appropriate value for determining whether an activation request packet is transmitted from a neighboring node at the sniff timing in the power saving listening method. There is no problem.

  In addition, in order to determine whether the activation request packet is transmitted from the neighboring node, the appropriate carrier sense level value varies depending on the node arrangement and the radio wave environment, and it may be expensive to design in advance. There is.

  Therefore, when intermittently performing a reception operation for a predetermined time, a communication device, a communication method, and a communication program that can use the optimum carrier sense level for the intermittent operation and can flexibly adjust the carrier sense level. It has been demanded.

  In order to solve such a problem, the first aspect of the present invention is a communication device that intermittently performs a reception operation for a predetermined reception time. (1) It has a carrier sense unit that performs carrier sense at the start of communication, and performs wireless communication. (2) a transmission control means for controlling transmission processing of the wireless communication means at the time of data packet transmission; (3) a reception control means for controlling reception processing of the wireless communication means; and (4) a carrier. Carrier sense switching means for switching the carrier sense level of the sense unit to the carrier sense level at the time of packet reception, and the transmission control means continuously sends the activation request packet in succession at the time of data packet transmission, and the activation response from the transmission destination When the packet is received, the data packet is transmitted, and the carrier sense unit performs a plurality of times of carrier for a predetermined time. If the activation control packet is received within a predetermined reception time after activation by intermittent carrier sense by the carrier sense unit, the reception control means A communication apparatus is characterized in that it returns an activation response packet and waits for data reception from the transmission source.

  According to a second aspect of the present invention, in a communication apparatus that intermittently performs a reception operation for a predetermined reception time, (1) a wireless communication unit that includes a carrier sense unit that performs carrier sense at the start of communication and performs wireless communication; 2) Carrier sense switching means for switching the carrier sense level of the carrier sense unit to the carrier sense level at the time of packet reception, and the wireless communication means continuously transmits the activation request packet in succession at the time of data packet transmission. When receiving the activation response packet, the wireless communication means transmits the data packet. When the wireless communication means receives the activation request packet within a predetermined reception time after activation, the activation response packet is transmitted to the transmission source of the activation request packet. The communication apparatus is characterized in that it waits for data reception from the transmission source.

  According to a third aspect of the present invention, in a communication apparatus that intermittently performs a reception operation for a predetermined reception time, (1) a wireless communication unit that includes a carrier sense unit that performs carrier sense at the start of communication and performs wireless communication; 2) At the time of data packet transmission, transmission control means for controlling the transmission processing of the wireless communication means, (3) reception control means for controlling the reception processing of the wireless communication means, and (4) the carrier sense level of the carrier sense unit, Carrier sense switching means for switching to the carrier sense level at the time of packet reception, and the transmission control means continuously transmits the activation request packet in succession at the time of data packet transmission, and receives the activation response packet from the transmission destination, the data packet It is a communication apparatus characterized by transmitting.

  According to a fourth aspect of the present invention, in a communication device that intermittently performs a reception operation for a predetermined reception time, the communication device includes a carrier sense unit that performs carrier sense at the start of communication, and includes a wireless communication unit that performs wireless communication. Is a communication device that continuously transmits activation request packets in succession at the time of data packet transmission, and transmits the data packet when receiving the activation response packet from the transmission destination.

  According to a fifth aspect of the present invention, there is provided a computer of a communication apparatus that intermittently performs a reception operation for a predetermined reception time. (1) A wireless communication unit that includes a carrier sense unit that performs carrier sense at the start of communication and performs wireless communication; (2) At the time of data packet transmission, transmission control means for controlling the transmission processing of the wireless communication means, (3) reception control means for controlling the reception processing of the wireless communication means, and (4) the carrier sense level of the carrier sense unit, the packet When functioning as a carrier sense switching means for switching to the carrier sense level at the time of reception, the transmission control means continuously transmits the activation request packet continuously at the time of data packet transmission, and receives the activation response packet from the transmission destination, The data sense is transmitted, and the carrier sense unit intermittently performs a plurality of carrier senses for a predetermined time. When receiving the activation request packet within a predetermined reception time after activation by intermittent carrier sense by the carrier sense unit, the reception control means causes the activation response packet to be returned to the transmission source of the activation request packet. It is a communication program characterized by waiting for data reception.

  According to a sixth aspect of the present invention, a computer of a communication apparatus that intermittently performs a reception operation for a predetermined reception time has a carrier sense unit that performs carrier sense at the start of communication and functions as a wireless communication unit that performs wireless communication. The wireless communication means is a communication program characterized by continuously transmitting activation request packets in succession at the time of data packet transmission, and transmitting the data packet when receiving an activation response packet from a transmission destination.

  According to a seventh aspect of the present invention, there is provided a communication method for intermittently performing a reception operation for a predetermined reception time. (1) A wireless communication unit includes a carrier sense unit that performs carrier sense at the start of communication, and performs wireless communication. A communication step, (2) a transmission control step in which the transmission post-transmission means controls transmission processing of the wireless communication means at the time of data packet transmission, and (3) reception control in which the reception control means controls reception processing of the wireless communication means. And (4) a carrier sense switching means for switching the carrier sense level of the carrier sense unit to a carrier sense level at the time of packet reception, and the transmission control means is activated at the time of data packet transmission. When the request packet is continuously transmitted continuously and the activation response packet is received from the transmission destination, the data packet is transmitted, and the carrier sense unit The carrier sense is intermittently performed a plurality of times for a predetermined time, and the reception control means receives an activation request packet within a predetermined reception time after activation by intermittent carrier sensing by the carrier sense unit. A communication method is characterized in that an activation response packet is returned to a packet transmission source and data reception standby from the transmission source is performed.

  According to an eighth aspect of the present invention, in the communication method of intermittently performing a reception operation for a predetermined reception time, the wireless communication unit includes a carrier sense unit that performs carrier sense at the start of communication, and includes a wireless communication step of performing wireless communication. The wireless communication means is a communication method characterized by continuously transmitting activation request packets in succession at the time of data packet transmission, and transmitting the data packet when receiving an activation response packet from a transmission destination.

  According to the present invention, when a reception operation for a predetermined time is intermittently performed, a carrier sense level optimum for the intermittent operation can be used, and the carrier sense level can be flexibly adjusted.

(A) 1st Embodiment Below, the 1st Embodiment of the communication apparatus of this invention, a communication method, and a communication program is described with reference to drawings.

  In the first embodiment, for example, an embodiment in which the present invention is applied to a communication apparatus included in a node configuring a sensor network will be described.

(A-1) Configuration of the first embodiment In the first embodiment, the sensor network is configured to have a large number of nodes distributed in space. In addition, each node realizes communication toward a transmission destination (for example, a sink node) by exchanging information data with other nodes in the vicinity.

  In addition, when performing wireless communication, each node performs communication correctly while performing an intermittent operation such as turning off a wireless device that is not used regularly in order to save power consumption.

  FIG. 1 is an internal configuration diagram illustrating an internal configuration of a communication device of a node according to the first embodiment. In FIG. 1, a communication device 10 according to the first embodiment includes at least a transmission control unit 1, a reception control unit 2, and a wireless communication unit 3.

  The wireless communication unit 3 wirelessly communicates packets according to a predetermined wireless communication method. Under the control of the transmission control unit 1 and the reception control unit 2, the wireless communication unit 3 is intermittently activated by turning on the power and entering the activated state (active state) or entering the sleep state by turning off the power. The starting operation is performed to perform packet communication. In this way, power saving can be performed by switching between the active state and the sleep state for communication.

  The wireless communication unit 3 includes a carrier sense unit 31. That is, the wireless communication unit 3 can apply, for example, a CSMA method as a communication method, and widely applies a method that is performed after carrier sensing whether other nearby nodes are communicating at the start of communication.

  The transmission control unit 1 controls transmission processing of the wireless communication processing unit 3. When receiving a packet transmission request, the transmission control unit 1 activates the wireless communication unit 3 to control transmission processing based on the power saving listening method.

  Here, the technique described in Non-Patent Document 1 can be applied to the power saving listening method. Also, when a packet transmission request is received, for example, when a sensor (not shown) acquires sensor information or when information data of another node is transferred.

  The transmission control unit 1 includes a radio unit activation processing unit 11, a CS (carrier sense) level switching processing unit 12, and a transmission processing unit 13 as main functions.

  The wireless unit activation processing unit 11 switches the wireless communication unit 3 to an activated state (active state) when receiving a packet transmission request.

  The CS level switching processing unit 12 confirms the carrier sense level of the wireless communication unit 3. If the CS level switching processing unit 12 is not at the transmission CS level at the time of packet transmission, the CS level switching processing unit 12 sets the carrier sense level of the wireless communication unit 3 at the transmission CS level. The level is changed.

  Here, the CS level at the time of transmission indicates a value of a carrier sense level optimum for performing collision avoidance using CSMA.

  In this way, by setting the carrier sense level of the wireless communication unit 3 to the CS level at the time of transmission, it is determined that there is a carrier when a reception intensity equal to or higher than the CS level at the time of transmission is detected, and when there is less than that, it can.

  The CS level switching processing unit 12 does not change the carrier sense level when the CS level at the time of transmission is reached.

  The transmission processing unit 13 continuously transmits activation request packets in order to activate a transmission destination node during packet transmission. The transmission processing unit 13 repeatedly transmits continuously until an activation response is returned from the transmission destination node. In addition, the transmission processing unit 13 may make a transmission failure when the activation response is not returned even after the specified time has elapsed. Further, the transmission processing unit 13 sets the state of the wireless communication unit 3 to the sleep state after completing the transmission of the data packet when the transmission fails or when the activation response is returned, and succeeding in the transmission. It is to switch.

  The reception control unit 2 controls the intermittent activation operation of the wireless communication unit 3 and controls the reception process of the wireless communication unit 3.

  The reception control unit 2 includes a reception processing unit 21, an intermittent operation control timer 22, a radio unit activation processing unit 23, a CS level switching processing unit 24, and a sniff operation unit 25.

  The reception processing unit 21 performs reception processing of the received packet given from the wireless communication unit 3, and determines whether it is a control packet or a higher-level processing packet based on the header information of the received packet To do. When the received packet is an activation response packet, the reception processing unit 21 notifies the transmission processing unit 13 that the activation response packet has been received. Other upper processing packets are notified to the upper processing unit.

  The intermittent operation control timer 22 is a timer that controls the timing of the intermittent operation of the wireless communication unit 3. For example, when operating at a period T, the intermittent operation control timer 22 provides timer information to the wireless unit activation processing unit 23 every T seconds. The intermittent operation control timer 22 functions as a trigger for starting the sniff operation, and can thereby activate the wireless communication unit 3.

  When the wireless unit activation processing unit 23 receives timer information from the intermittent operation control timer 22, the wireless unit activation processing unit 23 activates the wireless communication unit 3 (active state). Thereby, it can switch to the state which can receive a packet.

  The CS level switching processing unit 24 checks the carrier sense level of the wireless communication unit 3, and when the sniff operation is not at the sniff CS level, the carrier sense level of the wireless communication unit 3 is changed to the sniff time CS. The level is to change.

  The sniff CS level is a value of a carrier sense level for determining whether or not other neighboring nodes are transmitting start request packets. The sniff CS level value is desirably set lower than the transmission CS level value.

  Thereby, the reception of the packet can be detected even when the reception power intensity is weak by carrier sense during the sniff timing period by the sniff operation unit 25 described later, and the sniff timing period of the sniff operation unit 25 is set. The packet reception can be completed by the extension.

  If the sniffing CS level is set too low, the packet reception standby period is unnecessarily extended due to noise, and wasteful power consumption may be consumed.

  Further, when the sniffing CS level is set, the CS level switching processing unit 24 does not change the carrier sense level of the wireless communication unit 3.

  The sniff operation unit 25 performs carrier sense during the sniff timing period. Further, the sniff operation unit 25 determines that there is a predetermined number of carriers or more during the sniff timing period, determines that there is a high possibility of receiving a part of the packet, and extends the sniff timing period. is there. That is, the period of the activation state of the wireless communication unit 3 is extended only by the extended sniff timing period.

(A-2) Operation of the First Embodiment Next, the operation of processing in the communication device 10 of the node of the first embodiment will be described with reference to FIGS.

  In the following description, node A will be described as a packet transmission node and node B as a packet reception node. The sniffing CS level is set to a level lower than the transmitting CS level, and the transmission CS level of the nodes A and B is set to -77 dBm, and the sniffing CS level is set to -85 dBm. .

  In FIG. 2, first, the wireless communication unit 3 of the node A (transmission node) is in a sleep state.

Thereafter, when traffic destined for the node B is generated, in the node A, the wireless unit activation processing unit 11 gives an operation mode switching signal to the wireless communication unit 3 to switch the wireless communication unit 3 to the activated state.

  In node A, the CS level switching processing unit 12 confirms the carrier sense level, and switches the carrier sense level to the CS level during transmission when it is not the CS level during transmission. Thereby, it is possible to switch to an optimum carrier sense level for performing CSMA.

  Thereafter, the transmission processing unit 13 of the node A continuously gives activation request packets addressed to the node B to the wireless communication unit 3, and the wireless communication unit 3 continuously transmits the activation request packets. As a result, the activation request packet can be transmitted by the power saving listening method.

  On the other hand, in the node B (receiving node), the wireless communication unit 3 performs an intermittent activation operation under the control of the reception control unit 2.

  That is, in the reception control unit 2 of the node B, when the intermittent operation control timer 22 measures the period T, the wireless unit activation processing unit 23 gives an operation mode switching signal to the wireless communication unit 3. As a result, the wireless communication unit 3 turns on the power for a predetermined short sniff timing after receiving the operation mode switching signal to enter a packet reception standby state, and then turns off the power and cannot receive the packet. I have to.

  In the node B, the CS level switching processing unit 24 checks the carrier sense level, and switches the carrier sense level to the sniff CS level when it is not the sniff CS level.

  After switching to the CS level at the time of sniffing, the sniff operation unit 25 performs the sniff operation only during a predetermined sniff timing period. As described above, the activation request packet from the node A can be received by performing the sniffing operation after switching to the CS level at the time of sniffing.

  Here, the sniff operation will be described. The sniff operation unit 25 continues to perform carrier sense for a predetermined time.

  For example, it is assumed that the sniff operation unit 25 performs carrier sense 200 times in a predetermined time.

During this time, if the reception processing unit 21 can receive the activation request packet, the reception processing unit 21 notifies the transmission processing unit 13 to that effect, the transmission processing unit 13 returns an activation response, and the reception processing unit 21 receives the data packet. It becomes a reception standby state.

  In the node A, when the reception processing unit 21 receives the activation response, the transmission processing unit 13 is notified that the activation response has been received. Thereby, it is confirmed that both the node A and the node B are in the active state, and the transmission processing unit 13 of the node A transmits the data packet addressed to the node B.

  At this time, in the node B, the sniff operation unit 25 determines that there is a carrier even if the sniff operation unit 25 detects a predetermined number of times or more within the period of the sniff timing. When the carrier is detected a predetermined number of times or more in this way, it is highly likely that only a part of the activation request packet as shown in FIG. 3 has been received. Therefore, the sniff operation unit 25 sets the sniff timing period. Try to extend.

  Here, if the time for performing the sniffing operation is shortened, it is possible to obtain a high power saving effect because the time for keeping the wireless communication unit 3 active is reduced. There is a relation that only a part of the packet can be received.

  Therefore, if the sniff operation unit 25 receives the activation request packet as a result of performing the sniff operation, the sniff operation unit 25 extends the sniff operation period until the data packet is received thereafter. Thereafter, the sniff operation unit 25 switches the wireless communication unit 3 to the sleep state.

  If the activation request packet cannot be received, the sniff operation unit 25 immediately switches the wireless communication unit 3 to the sleep state.

  Here, the CS level during transmission and the CS level during sniff will be described.

  When the node A, which is the transmission node, continuously transmits the activation request packet, as described above, the wireless communication unit 3 of the node A sets the carrier sense level to the CS level during transmission.

  At this time, if the CS level at the time of transmission is set too low, carrier sense by CSMA reacts sensitively in the wireless communication unit 3 of the node A, and the transmission opportunity from the node A is reduced. There is a possibility that the continuous transmission interval of request packets becomes wide, and the probability of failure to receive the activation request packet at the Node B may increase.

  Therefore, it is more effective to set the CS level at the time of transmission as high as possible in consideration of the radio law and interference, for example.

  When the sniffing operation is performed in the node B that is the receiving node, the wireless communication unit 3 of the node B sets the carrier sense level to the CS level at the time of sniffing.

  Here, when performing the sniff operation, many wireless communication units 3 compliant with IEEE802.15.4 can receive a packet having an intensity of about −90 dBm. Therefore, for example, when the activation request packet of node A arrives at −80 dBm, even if only a part of the activation request packet can be received as shown in FIG. 3, the carrier sense level of the wireless communication unit 3 of node B Is −77 dBm (CS level during transmission), it is determined that there is no carrier, and the activation request packet cannot be received without shifting to a long sniffing operation.

  However, in the first embodiment, at the time of the sniffing operation, the CS level switching processing unit 24 of the reception control unit 2 switches the carrier sense level of the wireless communication unit 3 to the sniffing CS level (for example, −85 dBm). When the carrier sense is continuously performed by the operation 25, it can be determined that there is a carrier, and it is possible to receive the activation request packet by extending the sniff time.

(A-3) Effect of First Embodiment As described above, according to the first embodiment, the carrier sense level of the wireless communication unit is switched to the CS level during transmission during packet transmission, and during the sniff operation during sniffing. By switching to the CS level, the carrier can be detected at a level different from the carrier sense level of CSMA at the time of the sniffing operation. Therefore, while receiving a start request packet in a short sniff time and obtaining a high power saving effect, the sniffing The operation time can be extended, and failure to receive the activation request packet can be avoided.

(B) Second Embodiment Hereinafter, a second embodiment of the communication device, the communication method, and the communication program of the present invention will be described with reference to the drawings.

  The second embodiment will also be described by exemplifying an embodiment in which the present invention is applied to, for example, a communication device provided in a node constituting a sensor network.

(B-1) Configuration of the Second Embodiment In the first embodiment, the case where the sniff CS level is statically determined has been described. In the second embodiment, the case where the CS level is dynamically determined is described. To do.

  FIG. 4 is an internal configuration diagram illustrating an internal configuration of the node 20 according to the second embodiment. In FIG. 4, the node 20 of the second embodiment includes a transmission control unit 1, a reception control unit 2, and a wireless communication unit 3 as in the first embodiment.

  The reception control unit 2 includes, as main functions, a reception processing unit 21, an intermittent operation control timer 22, a radio unit activation processing unit 23, a CS level switching processing unit 24, a sniff operation unit 25, and a CS sniff level control unit 26. Have

  The second embodiment is different from the first embodiment in that the reception control unit 2 includes the CS level control unit 26, and other configuration requirements include the configuration described in the first embodiment. Therefore, in FIG. 4, the same or corresponding components as those in the first embodiment are denoted by the same reference numerals as those shown in FIG.

  The CS level control unit 26 adjusts the carrier sense level switched by the CS level switching processing unit 24 based on the sniff operation result of the sniff operation unit 25 and the reception result of the reception processing unit 21.

  For example, the sniff operation unit 25 that has determined that there is a high possibility that a part of the received packet has been received extends the period of the sniff timing as described in the first embodiment. Even in this case, when the reception processing unit 21 cannot receive the activation request packet, the CS level control unit 26 adjusts to increase the CS level at the time of sniffing.

  This is because the CS level at the time of sniffing is too low to react to noise and extend the sniff timing period even though the activation request packet has not arrived. Therefore, the adjustment as described above makes it difficult to extend the sniff time.

  Further, for example, when the sniff operation unit 25 does not extend the sniff time at all for a predetermined time (predetermined number of sniffs) or the reception processing unit 21 does not receive the activation request packet, the CS level control unit 26 Adjust to lower the CS level when sniffing.

  This is because reception of the activation request packet could not be detected because the CS level at the time of sniffing is high. Therefore, the adjustment is performed as described above.

  As a method for adjusting the sniff time CS level, for example, the CS level control unit 26 increases or decreases a predetermined value within a predetermined range between the upper limit value and the lower limit value of the sniff time CS level. realizable.

(B-2) Operation of Second Embodiment Next, the operation of processing in the node 20 of the second embodiment will be described with reference to FIG.

  Here, it is assumed that the packet transmission node is node A and the reception node is node B.

Also, for convenience of explanation, the initial value of the CS level at the time of sniffing is set to a sufficiently small value so that even if the reception intensity such as noise is small, it reacts as there is a carrier.

  First, in the node B (receiving node), the wireless communication unit 3 repeats the intermittent activation operation under the control of the reception control unit 2.

  At this time, since the sniff operation control unit 26 has selected a small value of the CS level at the time of sniffing, the carrier sense is likely to react sensitively, and the reception processing unit 21 may have received only a part of the activation request packet. It becomes easy to judge that is high.

  For this reason, the sniff operation unit 25 extends the sniff timing period. However, since the activation request packet is not actually transmitted, the reception processing unit 21 cannot receive the activation request packet.

  At this time, that is, when the CS level control unit 26 detects that the sniff operation period has been extended and the activation request packet has not been received yet, the sniffing CS level is adjusted to be increased by a predetermined value.

  The CS level control unit 26 repeats the operation again after adjusting the CS level at the time of sniffing, so that the sniff time is not unnecessarily extended due to the influence of noise or the like.

  If the CS level at the time of sniffing increases too much, it becomes difficult to receive the activation request packet, so that the CS level control unit 26 operates to lower the CS level at the time of sniffing.

  As described above, the CS level control unit 26 adjusts the sniff CS level, so that the appropriate value is settled in the course of operation without setting an appropriate value in advance.

(B-3) Effects of the Second Embodiment As described above, according to the second embodiment, the sniff CS level is dynamically changed based on the reception strength of the activation request packet from the transmission node. Therefore, it is not necessary to determine the CS level at the time of sniffing in advance, and it is possible to flexibly cope with node arrangement, radio wave environment and the like.

  As a result, in addition to the effects of the first embodiment, the second embodiment can reduce the cost of appropriately designing the sniff CS level and can avoid losing the activation request packet.

(C) Other Embodiments (C-1) The functional configurations of the wireless communication unit, transmission control unit, and reception control unit described in the first and second embodiments are block diagrams in FIGS. 1 and 4 for convenience of explanation. It showed in. The arrangement of each functional configuration is not limited to that shown in FIGS. 1 and 4, and may be arranged in a distributed manner as long as each function can be realized.

(C-2) The processing of each constituent requirement of the communication device according to the first and second embodiments is realized by software processing. For example, each component is configured to have a CPU, ROM, RAM, EEPROM, etc., and the CPU executes a processing program stored in the ROM using data necessary for processing. The functions described in the first and second embodiments can be realized. Of course, it may be realized by a hardware configuration.

It is an internal block diagram which shows the internal structure of the node of 1st Embodiment. It is explanatory drawing explaining the intermittent operation | movement of a node. It is explanatory drawing explaining sniff operation | movement. It is an internal block diagram which shows the internal structure of the node of 2nd Embodiment.

  DESCRIPTION OF SYMBOLS 10 and 20 ... Communication apparatus, 1 ... Transmission control part, 2 ... Reception control part, 3 ... Wireless communication part, 11 ... Radio | wireless part starting process part, 12 ... CS level switching process part, 13 ... Transmission process part, 21 ... Reception Processing unit, 22 ... intermittent operation control timer, 23 ... wireless unit activation processing unit, 24 ... CS level switching processing unit, 25 ... sniff operation unit, 26 ... CS level control unit.

Claims (15)

In a communication device that intermittently performs a reception operation for a predetermined reception time,
A wireless communication means having a carrier sense unit for performing carrier sense at the start of communication and performing wireless communication;
A transmission control means for controlling the transmission processing of the wireless communication means at the time of data packet transmission;
Reception control means for controlling reception processing of the wireless communication means;
Carrier sense switching means for switching the carrier sense level of the carrier sense unit to the carrier sense level at the time of packet reception;
With
The transmission control means, when transmitting a data packet, continuously transmits the activation request packet in succession, and upon receiving the activation response packet from a transmission destination, transmits the data packet,
The carrier sense part intermittently performs a plurality of carrier senses for a predetermined time,
The reception control means, when receiving an activation request packet within a predetermined reception time after activation by intermittent carrier sense by the carrier sense unit, causes an activation response packet to be returned to the transmission source of the activation request packet, A communication device for waiting for data reception from a transmission source. In a communication device that intermittently performs a reception operation for a predetermined reception time,
A wireless communication means having a carrier sense unit for performing carrier sense at the start of communication and performing wireless communication;
Carrier sense switching means for switching the carrier sense level of the carrier sense unit to the carrier sense level at the time of packet reception;
With
The wireless communication means continuously transmits the activation request packet in succession at the time of data packet transmission, and transmits the data packet when receiving the activation response packet from the transmission destination.
When the wireless communication means receives an activation request packet within a predetermined reception time after activation, the wireless communication means returns an activation response packet to the transmission source of the activation request packet and waits for data reception from the transmission source. A communication device. In a communication device that intermittently performs a reception operation for a predetermined reception time,
A wireless communication means having a carrier sense unit for performing carrier sense at the start of communication and performing wireless communication;
A transmission control means for controlling the transmission processing of the wireless communication means at the time of data packet transmission;
Reception control means for controlling reception processing of the wireless communication means;
Carrier sense switching means for switching the carrier sense level of the carrier sense unit to the carrier sense level at the time of packet reception;
With
The transmission apparatus, wherein when transmitting a data packet, the activation request packet is continuously transmitted continuously, and when the activation response packet is received from a transmission destination, the data packet is transmitted. In a communication device that intermittently performs a reception operation for a predetermined reception time,
A carrier sense unit that performs carrier sense at the start of communication, and includes wireless communication means that performs wireless communication,
The communication device, wherein the wireless communication means continuously transmits the activation request packet in succession at the time of data packet transmission, and transmits the data packet when the activation response packet is received from a transmission destination.   The communication apparatus according to claim 2, wherein the carrier sense unit intermittently performs a plurality of carrier senses for a predetermined time.   The communication device according to claim 1, wherein the carrier sense switching unit switches a carrier sense level of the carrier sense unit to a carrier sense level at the time of packet transmission.   The communication device according to claim 1, wherein a carrier sense level at the time of packet transmission is different from a carrier sense level at the time of packet reception.   The communication device according to claim 1, wherein the carrier sense switching unit switches the carrier sense level to a packet transmission level after the wireless communication unit is activated.   9. The communication apparatus according to claim 1, further comprising a reception level adjustment unit that dynamically adjusts a reception level based on a reception state of a reception packet. When the carrier sense unit determines that there is a carrier by carrier sense during reception standby within the reception time, and a packet has not been received,
The communication apparatus according to claim 9, wherein the reception level adjustment unit adjusts the reception level to increase. When the carrier sense unit determines that there is no carrier for a predetermined period by carrier sense during reception standby within the reception time,
The communication apparatus according to claim 9 or 10, wherein the reception level adjusting means adjusts the reception level so as to decrease. A computer of a communication device that intermittently performs a reception operation for a predetermined reception time,
A wireless communication means having a carrier sense unit for performing carrier sense at the start of communication and performing wireless communication;
A transmission control means for controlling the transmission processing of the wireless communication means at the time of data packet transmission;
Reception control means for controlling reception processing of the wireless communication means;
Carrier sense switching means for switching the carrier sense level of the carrier sense unit to the carrier sense level at the time of packet reception;
As a function,
The transmission control means, when transmitting the data packet, continuously transmits the activation request packet continuously, and upon receiving the activation response packet from the transmission destination, causes the data packet to be transmitted,
The carrier sense unit intermittently performs a plurality of carrier senses for a predetermined time,
The reception control means, when receiving an activation request packet within a predetermined reception time after activation by intermittent carrier sense by the carrier sense unit, causes an activation response packet to be returned to the transmission source of the activation request packet, A communication program characterized by waiting for data reception from a transmission source. A computer of a communication device that intermittently performs a reception operation for a predetermined reception time,
It has a carrier sense unit that performs carrier sense at the start of communication, and functions as a wireless communication unit that performs wireless communication.
The wireless communication means continuously transmits the activation request packet in succession at the time of data packet transmission, and transmits the data packet when receiving the activation response packet from a transmission destination. In a communication method for intermittently performing a reception operation for a predetermined reception time,
The wireless communication means has a carrier sense unit that performs carrier sense at the start of communication, and performs a wireless communication step of performing wireless communication;
A transmission control step in which the transmission post-transmission means controls the transmission processing of the wireless communication means at the time of data packet transmission,
A reception control step, wherein the reception control means controls the reception processing of the wireless communication means;
A carrier sense switching step, wherein the carrier sense switching means switches the carrier sense level of the carrier sense unit to the carrier sense level at the time of packet reception;
Have
The transmission control means, when transmitting the data packet, continuously transmits the activation request packet continuously, and upon receiving the activation response packet from the transmission destination, causes the data packet to be transmitted,
The carrier sense unit intermittently performs a plurality of carrier senses for a predetermined time,
The reception control means, when receiving an activation request packet within a predetermined reception time after activation by intermittent carrier sense by the carrier sense unit, causes an activation response packet to be returned to the transmission source of the activation request packet, A communication method characterized by waiting for data reception from a transmission source. In a communication method for intermittently performing a reception operation for a predetermined reception time,
The wireless communication means has a carrier sense unit for performing carrier sense at the start of communication, and has a wireless communication step for performing wireless communication,
The wireless communication means continuously transmits the activation request packet continuously at the time of data packet transmission, and transmits the data packet when receiving the activation response packet from a transmission destination.

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