JP2007142520A - Wireless communication apparatus and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus and system capable of saving power by changing a communication output in a way of being adaptable to the wireless quality of a communication interval and setting proper power in an ordinary data communication sequence. <P>SOLUTION: The communication apparatus for performing wireless data communication includes: a reception means 104; an arithmetic means 108; and a transmission means 102, the reception means receives data from a transmission side at reception, the arithmetic means calculates the excess value or the deficient value of a proper transmission output from the received data and stores the excess value or the deficient value to an ACK frame, the transmission means returns the resulting frame to a transmission side, the reception means receives the ACK frame returned from a receiver side in transmission, the arithmetic means calculates the proper transmission output on the basis of the excess value or the deficient value stored in the ACK frame, and the transmission means transmits the calculated proper transmission output. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus and a wireless communication system, and in particular, in wireless data communication, communication settings and power control are performed by wireless settings such as transmission output and reception sensitivity suitable for channel quality in the wireless section and communication volume in the wireless section. The present invention relates to a wireless communication apparatus and a wireless communication system.

  In the conventional wireless communication apparatus and wireless communication system, the transmission output is increased step by step, and the transmission output when the frame error rate of the communication partner falls below a predetermined value is set as the initial transmission output. The transmission output that achieves the above is calculated by actual measurement and calculation, and communication in the wireless section is performed with appropriate transmission power. (For example, refer to Patent Document 1).

JP 2000-184435 A

  The conventional wireless communication apparatus and the power control method of the wireless communication system are configured as described above, and since the optimum transmission power is continuously received from the communication partner until the frame error rate reaches a predetermined level, until the actual communication is started. Therefore, there is a problem that communication for setting optimum transmission power hinders communication performance of actual wireless data communication.

  In addition, in the conventional power control method of the wireless communication apparatus and the wireless communication system, the communication for determining the transmission power appropriate value and the communication for performing the actual data communication are different methods, respectively. There was a problem of reducing the speed.

  The present invention has been made in order to solve the above-described problems, and is capable of saving power by changing the transmission output so that it can be adapted to the wireless quality of the communication section. An object of the present invention is to provide a wireless communication apparatus and a wireless communication system capable of setting appropriate power.

  A wireless communication device according to the present invention is a communication device that performs wireless data communication, and includes a reception unit, a calculation unit, and a transmission unit. During reception, the reception unit receives data from the transmission side, and The calculation means calculates the excess / deficiency value of the appropriate transmission output from the received data, stores this excess / deficiency value in the ACK frame, and sends it back to the transmission side by the transmission means. During transmission, the ACK returned from the reception side The frame is received by the receiving unit, and an appropriate transmission output is calculated by the calculating unit based on the excess / deficiency value stored in the ACK frame, and data is transmitted by the transmitting unit with the calculated appropriate transmission output value. It is a thing.

  The radio communication apparatus and radio communication system according to the present invention are configured as described above, and an ACK frame returned to the transmission source at the time of data reception includes an excess of an appropriate transmission output calculated from information at the time of reception such as a reception level and a frame error rate. Since the shortage value is stored and the transmission source resets the transmission output based on the information and communicates, the wireless communication is performed with more power saving than the conventional wireless communication device and wireless communication system. It becomes possible.

  In addition, a sensor such as a humidity sensor is provided so that the transmission output can be set based on the weather conditions obtained by the sensor, and wireless communication can be performed with a transmission output suitable for the weather conditions. It becomes possible to reduce.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a wireless communication apparatus according to the first embodiment. In FIG. 1, an antenna 101 transmits and receives wireless data. The transmission unit 102 is connected to the antenna 101 and performs a communication operation under the control of the control unit 107. The transmission output setting unit 103 sets the power value of the transmission output.

The receiving unit 104 is connected to the antenna 101 and performs a receiving operation. The reception level measurement unit 105 measures RSSI. The line quality measurement unit 106 detects a reception error (FER) when receiving data.
The control unit 107 controls the operation of the entire wireless device. The memory 109 stores a reception error (FER) threshold, a transmission power value, and the like. The calculation unit 108 calculates the optimum transmission power based on FER and RSSI. The external I / F 110 is an interface (I / F) for connecting to an external device such as a server (PC) or a sensor.

  FIG. 2 is a schematic diagram illustrating a configuration of a wireless communication network configured by the wireless communication device according to the first embodiment. In FIG. 2, a public line network 201 is a communication line for performing Internet communication. The server device 202 is connected to the communication line 201, and controls the wireless communication network to perform information communication with the outside.

  The server I / F device 203 is an I / F for the server device 202 to perform data transmission / reception in the wireless section with the wireless relay device or the terminal devices 204 and 205 in the wireless communication network. The wireless relay device 204 performs data relay when data does not reach between the server I / F device 203 and the terminal device 205. The terminal device 205 is configured to transmit data collected from the sensor device 206 to the server device 202 under the control of the server device 202.

  The wireless communication device in FIG. 1 can be used as any of the server I / F device 203, the wireless relay device 204, and the terminal device 205 in the wireless communication network in FIG. With respect to the wireless communication apparatus according to Embodiment 1 configured as described above, an operation for determining an appropriate transmission power value will be described with reference to the flowchart of FIG.

  First, the data transmitting side transmits data from the transmitting unit 102 through the antenna 101 in step (hereinafter abbreviated as ST) 301.

In ST302, the receiving side performs a receiving operation in receiving section 104 through antenna 101, and measures the RSSI by receiving level measuring section 105 in ST303 during data reception.
In ST304, channel quality measurement section 106 checks the received data frame and calculates an error rate.

  In ST305, calculation unit 108 calculates an excess / deficiency value of the transmission output based on the measured RSSI and error rate. When the error rate is 0%, it is considered that the transmission output is excessively high, so surplus power is calculated based on the calculated RSSI. On the other hand, when the error rate is greater than 0%, the transmission power is insufficient, so the RSSI is reduced by the loss due to the radio section, and the error rate is high. Therefore, the shortage is calculated by the following calculation.

In general, the following calculation is established between the error rate and RSSI and the received power.
Rerr (%) = a * Prssi (dBm) + b (1)
Prssi (dBm) = k * Prcv (dBm) + Offset (2)
Here, Rerr is the error rate, Prssi is the RSSI value, Prcv is the received power, a and b, k and Offset are values depending on the configuration of the receiving unit 104, and are set at the time of shipment from the factory and stored in the memory 109. It is what.

In general, the following relational expression is established between transmission power and reception power.
Prcv (dBm) = Psnd (dBm) + Gsnd (dBm) -L (dBm) + Grcv (dBm) (3)
Here, Prcv is the received power, Psnd is the transmission output, Gsnd is the antenna gain on the transmission side, Grcv is the antenna gain on the reception side, and L is the spatial loss in the radio section.

  Since Gsnd and Grcv are design values, they are stored in the memory 109 in advance. L depends on the distance of the wireless section. In the wireless communication network of the present invention, the distance of the wireless section is not uniquely determined. Therefore, calculate Prcv with Rerr = O (%) from Eqs. (1) and (2), calculate Psnd-L back with Eq. In step ST305, the power shortage is calculated.

  Next, in ST306 and ST307, the receiving side apparatus generates an ACK frame in transmitting section 102. At this time, the excess / deficiency value of the transmission power calculated by the calculation unit 108 is stored in the payload of the ACK frame. After that, in ST308, transmission section 102 returns an ACK frame storing the transmission power excess / deficiency value to the data transmission source apparatus via antenna 101.

  The transmission source apparatus waits for an ACK frame to be returned in ST309 after data transmission. When receiving section 104 cannot detect the carrier of the ACK frame for a certain time or more in ST310, it is determined that the data has not reached the counterpart apparatus because the transmission output is low, and transmission output setting section 103 in ST311 and ST312 The transmission output is increased by 1 dBm with respect to the current output, the set transmission power is stored in the memory unit 109, and then transmission is performed again to the counterpart device at ST301 with the set transmission power.

  In ST310, the transmission source apparatus receives the ACK frame when receiving section ACK frame carrier is detected within a predetermined time in ST310. In ST313, receiving section 104 analyzes the payload of the ACK frame and reads the excess / deficiency value of the transmission power. When the excess / deficiency value is 0, the transmission output is not reset and the state transits to the transmission / reception state. If the excess / deficiency value is other than 0, the excess / deficiency power returned by the transmission output setting unit 103 in ST314 and ST315 is added to or subtracted from the current transmission output, and the transmission output is reset. The reset transmission output is stored.

  With the configuration as described above, in the first embodiment, the difference between the minimum transmission output required for the frame error rate to be 0% in the ACK frame and the current transmission output is stored and returned, Since the transmission power is reset based on the deficient value, the transmission power can be converged to an appropriate transmission power during normal data communication, and a more power-saving wireless communication device can be obtained.

  Further, the transmission output set value can be stored in the memory 109 for each communication partner, and wireless data communication can be performed with appropriate transmission power with an error rate of 0% for each communication partner. It is possible to save power with the entire wireless device.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a block diagram showing the configuration of the second embodiment. In this figure, the same or corresponding parts as in FIG. A difference from FIG. 1 is that a nonvolatile memory 111 is provided.

  In the first embodiment described above, the case where the proper transmission power is reset between the devices that are always performing data transmission / reception has been described. However, in the second embodiment, the proper transmission power changes for each counterpart communication device in the memory 109. The power value is updated every time, and the non-volatile memory 111 is provided as shown in FIG. 4 to store the proper transmission power stored for each device in the non-volatile memory 111 when the power is shut down according to an instruction from the server device 202. It is what I did.

  With the above configuration, it is possible to perform wireless data communication with the proper transmission output stored before the power is turned off when the power is restored, and the power can be further saved because the convergence to the proper transmission power is accelerated.

  In addition, in the wireless relay device 204 and the terminal device 205 in which data communication occurs only about several times a day and the power is saved by shutting off the power supply at other times, the appropriate power is determined from the stored value. By performing the setting, the convergence of the appropriate power is performed at an early stage, so that the power consumption can be suppressed.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a diagram showing a format of a proper transmission output history provided in the third embodiment. Since the configuration of the wireless communication apparatus is the same as that of the first embodiment, illustration and description thereof are omitted.

  In the first embodiment, when the proper transmission output is changed, the changed proper transmission output value is stored in the memory 109. However, in the third embodiment, the proper transmission output history table having the format shown in FIG. 501 and the current appropriate transmission output and the maximum value of the appropriate transmission output so far are set for each communication partner.

  With the above configuration, even when communication is interrupted due to fluctuations in the channel quality in the wireless section, it is possible to quickly recover communication using the flow shown in FIG. Hereinafter, the communication section recovery method will be described with reference to the flowchart shown in FIG.

  First, the communication device that detects the communication interruption extracts the maximum value of the appropriate transmission output to the corresponding wireless device from the appropriate transmission output history 501 stored in the memory 109 in ST601 and ST602, and transmits it in the transmission output setting unit 103. Set the output to the maximum value for proper transmission output.

  The transmission side transmits data from the transmission unit 102 through the antenna 101 with the transmission output set by the transmission output setting unit 103 in ST603.

In ST604, the receiving unit 104 performs reception operation through the antenna 101 in ST604, and measures RSSI in the reception level measurement unit 105 in ST605 when receiving data.
In ST606, channel quality measurement section 106 checks the received data frame and calculates an error rate.

  Next, in ST607, operation section 108 calculates an excess / deficiency value of the transmission output based on the measured RSSI and error rate. When the error rate is 0%, it is considered that the transmission output is excessively high, so surplus power is calculated based on the calculated RSSI. Further, when the error rate is greater than 0%, the transmission power is insufficient, so the loss due to the radio section, RSSI decreases, and the error rate is high, so the calculation unit 108 calculates the shortage.

  Thereafter, in ST608 and ST609, the receiving side apparatus generates an ACK frame in transmitting section 102. At this time, the excess / deficiency value of the transmission power calculated by the calculation unit 108 is stored in the payload of the ACK frame. In ST610, transmitting section 102 returns an ACK frame storing the transmission power excess / deficiency value to the data transmission source apparatus via antenna 101.

  The transmission source apparatus waits for an ACK frame to be returned in ST611 after data transmission. In ST612, if receiving section 104 cannot detect the carrier of the ACK frame for a certain time or more, it is determined that data has not arrived at the counterpart apparatus because the transmission output is low, and transmission is performed by transmission output setting section 103 in ST613 and ST614. The output is increased by 1 dBm with respect to the current output, the set transmission power is stored in the memory unit 109, and transmission is performed again to the counterpart device at ST603 with the set transmission power.

  In ST612, the transmission source apparatus receives an ACK frame when receiving section ACK frame carrier is detected within a predetermined time in ST612. In ST615, receiving section 104 analyzes the payload of the ACK frame and reads the excess / deficiency value of the transmission power. When the excess / deficiency value is 0, the transmission output is not reset, and it is assumed that the wireless communication can be restored with the appropriate transmission power value, and the current value and the maximum value of the appropriate transmission output history 501 stored in the memory 109 are set. Update and end the recovery operation. If the excess / deficiency value is other than 0, the excess / deficiency power returned by the transmission output setting unit 103 in ST616 and ST617 is adjusted to the current transmission output, the transmission output is reset, and stored in the memory 109. The current value and the maximum value of the appropriate transmission output history 501 being updated are updated.

  Since the third embodiment is configured as described above and includes means for storing the maximum value of the appropriate transmission output during normal communication for each communication partner, the wireless quality in the wireless section is abruptly deteriorated and communication is performed. Even when the interruption occurs, it is possible to obtain a wireless communication apparatus that sets the appropriate transmission output from the stored maximum value to the appropriate wireless output and quickly restores communication.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a block diagram showing a configuration of the fourth embodiment. In this figure, the same or corresponding parts as in FIG. The difference from FIG. 1 is that a humidity sensor 112 is provided.

  In the first embodiment, the case where the transmission output is converged to an appropriate value by storing the excess / deficiency value of the appropriate transmission output in the ACK frame during normal wireless data communication to save power is described. As shown in FIG. 7, the present embodiment 4 includes a humidity sensor 112 that detects the current humidity and humidity fluctuations, and sets an appropriate transmission power value according to the humidity change during normal communication. It is made to fluctuate with.

  Next, an operation of determining an appropriate transmission power value based on the humidity fluctuation detected by the humidity sensor 112 will be described with reference to the flowchart of FIG. 8 for the wireless communication apparatus according to the fourth embodiment.

  In ST801, transmission output setting section 103 updates the appropriate transmission output value based on the excess / deficiency value of the appropriate transmission output stored in the ACK frame returned from the counterpart device.

  Next, when the humidity sensor 112 detects a change in humidity in ST802 and ST803, the calculation unit 108 determines the appropriate transmission output at the current humidity and the value in ST801 based on the current humidity and the change value sent from the humidity sensor 112. The transmission output difference is calculated.

  In general, the characteristics of humidity vs. propagation loss can be determined at the time of design depending on the frequency used for wireless communication, and the pre-stored value in the memory 109 is pre-stored in the memory 109 at the time of shipment. The transmission output setting unit 103 reflects the excess / deficiency value in the appropriate transmission output. Thereafter, in ST804, the proper transmission output is stored in memory 109.

  Since the fourth embodiment is configured as described above, even if the propagation loss fluctuates due to changes in weather conditions, a wireless communication device with a high power saving effect can be obtained by always performing wireless communication with an appropriate transmission output. Obtainable.

Embodiment 5. FIG.
Next, a fifth embodiment of the present invention will be described. Since the configuration of the wireless communication apparatus is the same as that of the second embodiment, illustration and description thereof are omitted.

  In the second embodiment described above, the case where the proper transmission power is stored in the nonvolatile memory when the power is turned off, and the wireless communication is started with the stored proper transmission power when the power is turned on again. In the fifth embodiment, when the server device 202 restarts the wireless relay device 204 and the terminal device 205, the weather information at the time of restart is notified.

  Next, the operation for determining the initial value of the appropriate transmission power value for the wireless communication apparatus according to the fifth embodiment will be described with reference to the flowchart of FIG.

  In ST 901 and ST 902, server apparatus 202 makes a startup request to radio relay apparatus 204 or terminal apparatus 205 via server I / F apparatus 203. At this time, the transmission output setting unit 103 of the server I / F device 203 performs a transmission operation with an appropriate transmission output value for the communication partner stored in the memory 109. At this time, the server apparatus 202 issues a startup request to the wireless relay apparatus 204 or the terminal apparatus 205, and simultaneously transmits weather information such as humidity at that time, and then transitions to the normal communication state of ST903.

  If the activation request is received from server apparatus 202 in ST904, wireless relay apparatus 204 or terminal apparatus 205 differs from the weather information received from server apparatus 202 to the appropriate transmission output value stored in memory 109 by calculation unit 108 in ST905. The value is calculated and added to the appropriate transmission output value.

  In ST905, transmission output setting section 103 sets the appropriate transmission output value calculated by computing section 108, and transitions to the communication start waiting state in ST906. It should be noted that the wireless relay device 204 and the terminal device 205 also return the appropriate transmission output excess / deficiency value according to the flow of FIG. 3 even during the activation request between the server device 202 and the wireless relay device 204 and the terminal device 205.

  Since the fifth embodiment is configured as described above, the wireless communication apparatus can be used even if the propagation loss of the wireless section changes due to changes in atmospheric weather conditions when the wireless communication apparatus recovers from the standby mode when saving power. When the device 202 requests the restoration operation, the weather information at that time is transmitted at the same time, so that wireless communication can be performed with the initial value of the appropriate transmission output following the change in propagation loss, and the power consumption can be suppressed.

It is a block diagram which shows the structure of the radio | wireless communication apparatus by Embodiment 1 of this invention. It is the schematic which shows the network structure of the radio | wireless communications system by Embodiment 1 of this invention. It is a flowchart which shows the operation | movement of the appropriate transmission power value setting by Embodiment 1 of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus by Embodiment 2 of this invention. It is a figure which shows the format of the transmission output log | history by Embodiment 3 of this invention. It is a flowchart which shows the operation | movement of communication restoration at the time of communication interruption by Embodiment 3 of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus by Embodiment 4 of this invention. It is a flowchart which shows the operation | movement of the appropriate transmission output setting by Embodiment 4 of this invention. It is a flowchart which shows the operation | movement of the appropriate transmission output initial setting by Embodiment 5 of this invention.

Explanation of symbols

101 antenna, 102 transmitting unit, 103 transmission output setting unit, 104 receiving unit,
105 reception level measurement unit 106 line quality measurement unit 107 control unit
108 arithmetic unit, 109 memory, 110 external I / F, 111 non-volatile memory,
112 humidity sensor, 201 public network, 202 server device,
203 server I / F device, 204 wireless relay device, 205 terminal device
206 Sensor device, 501 Appropriate transmission output history table.

Claims (5)

  A communication apparatus that performs wireless data communication includes a receiving unit, a calculating unit, and a transmitting unit. When receiving, data from the transmission side is received by the receiving unit, and proper transmission output is received from the received data by the calculating unit. The excess / deficiency value is calculated, stored in an ACK frame and sent back to the transmission side by the transmission means, and at the time of transmission, the reception means receives the ACK frame returned from the reception side. A wireless communication characterized in that an appropriate transmission output is calculated by the calculating means based on the excess / deficiency value stored in an ACK frame, and data is transmitted by the transmitting means with the calculated appropriate transmission output value. apparatus.   2. The wireless communication apparatus according to claim 1, wherein storage means for storing the appropriate transmission output is provided for each communication partner, and transmission is performed with the appropriate transmission output stored at the time of resumption after communication interruption.   Each communication partner is provided with means for storing a fluctuation value of the transmission output stored in the ACK frame, and when communication is interrupted, transmission is performed by setting a transmission output corresponding to the fluctuation value. The wireless communication apparatus according to claim 1.   The monitoring means for monitoring changes in weather conditions, and correction means for correcting the transmission output from the weather information obtained by the monitoring means, wherein the transmission output is reset according to the weather conditions. The wireless communication device according to 1.   A wireless communication system according to claim 2, wherein monitoring means for monitoring changes in weather conditions is provided in the wireless communication apparatus according to claim 2, and wireless communication is performed with a transmission output corresponding to the weather conditions when restarting after the communication is cut off.

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