KR100538944B1 - Apparatus and method for optimizing transmit power of wireless personal ad-hoc network - Google Patents

Abstract

Apparatus and method for performing a protocol for optimizing transmission power in a wireless LAN, in particular, apparatus and method for performing a protocol for optimizing transmission power during multi-point communication (1: N) in a wireless private simple network This is disclosed. An apparatus for optimizing a transmission power of a wireless private simple network includes a communication unit configured to transmit and receive data packets through air; And a controller configured to output a control signal for adjusting transmission power according to the connection information of the data packet received through the communication unit. The connection information includes received signal strength and / or link quality information. According to the apparatus and method for optimizing the transmission power of a wireless private simple network, it is possible to adjust the transmission power while communicating with each node during multi-point communication (1: N) in a wireless private simple network, thereby maintaining an appropriate level of communication quality. The transmission power consumption can be reduced.

Description

Apparatus and method for optimizing transmit power of wireless personal ad-hoc network

The present invention relates to an apparatus and method for performing a protocol for optimizing transmission power in a wireless local area network, and in particular, to optimize transmission power during multi-point communication (1: N) in a wireless private simple network. An apparatus and method for performing a protocol for

Wireless communication technology is a technology that uses radio waves as a transmission medium for information. Wireless communication devices making up a wireless communication system are characterized by mobility, portability and simplicity. In addition, the wireless communication system has a feature that can easily transmit information regardless of the location of the user, the application range is gradually expanding. Among them, wireless local area network (WLAN) compensates for the shortcomings of existing wired LAN through wireless communication technology. Wireless LAN has the advantages of flexibility and ease of installation because the LAN can be extended through wireless channels even in a difficult installation environment of a wired LAN.

On the other hand, the packet transmission method in wireless communication can be divided into centralized and distributed. In the centralized type, communication between the node and the central node, as well as communication between the node and the node, is possible only by the relay of the central node. On the other hand, the distributed structure uses the omni-directional nature of the radio to directly communicate with each other without having a central node. In particular, in the case of a network consisting only of mobile terminals such as a private simple network (PAN), the mobility can be easily secured through a distributed structure.

As described above, a mobile terminal used in a wireless network receives power from a battery. However, the life of the battery is finite. Accordingly, methods for allowing each node to transmit data at a minimum transmit power by exchanging transmit power information in order to prolong the life of the battery are disclosed in US Pat. Nos. 5,450,616 and 5,465,398 (WO 95/10142).

U.S. Patent 5,450,616 discloses a power control apparatus and method in a wireless LAN. First, a transmitting node transmits a data packet including power information for initial packet transmission to a master in a wireless LAN environment. The master calculates a power suggestion value from the received power information data and the signal quality data. The master sends the result of calculating the power proposal value to the slave. The transmitting node adjusts the packet transmission power according to the received power proposal calculation result.

U.S. Patent 5,465,398 (WO 95/10142) also discloses a method for automatically controlling the power level of a packet communication link. The target node compares the received signal strength indicator (RSSI) with the stored minimum signal strength of the received signal. As a result of the comparison, if the received RSSI is not greater than the minimum signal strength, the stored minimum signal strength is updated and the comparison node is informed to the source node. However, as a result of the comparison, if the received RSSI is greater than the minimum signal strength, the stored minimum signal strength is updated and the comparison node is informed to the source node. That is, the power level of the source node is adjusted according to the comparison result of the minimum signal strength with the RSSI of the signal received at the target node.

According to the above two patents, in case of point-to-point (1: 1) communication between two nodes, transmission / reception power between two devices can be properly adjusted. However, in the case of multi-point (1: N) communication, which is generally expected in a wireless LAN, the transmission and reception power of each communication device cannot be optimized by the method of the two patents mentioned above. This is because it is difficult to keep the power of all devices participating in the communication to a minimum by simply increasing and decreasing transmission power. That is, according to the above two patents, the transmission and reception power is optimized based on the connection with the worst transmission state.

One of the multi-point communication methods in the wireless LAN is Bluetooth technology. Bluetooth technology is a wireless communication method without a centralized management function, which allows data to be transmitted and received through a wireless connection within a short distance without connecting cables between devices equipped with Bluetooth. Bluetooth provides one-to-one or one-to-multiple connections, but because it lacks a central control structure, it is difficult to operate on a simple private network. Two or more units sharing the same channel constitute a Piconet. Therefore, if Bluetooth-equipped devices form a private ad-hoc network (hereinafter referred to as PAN), one of the Bluetooth-equipped devices serves as a master of the piconet to manage the PAN. For convenience, let's call this unit a master. Other devices except the master act as slaves to the piconet, and for convenience, these devices are called slaves. In the PAN configured as described above, the master needs to adjust the transmission power to the slave to the minimum that communication is possible to reduce the power loss and maintain the communication quality constant.

An object of the present invention is an apparatus for performing a protocol for optimizing the transmission power to reduce the power consumption of the transmission power while maintaining the appropriate communication quality of the nodes for multi-point communication (1: N) in a wireless private simple network; To provide a way.

An apparatus for optimizing transmission power in a wireless private simple network according to the present invention for achieving the above object is a communication unit for transmitting and receiving data packets through the air; A power measuring unit measuring a received power of the data packet received through the communication unit and a reception state parameter of the data packet; And a controller for requesting transmission power adjustment to a slave transmitting the data packet based on the received power of the data packet measured by the power measuring unit and the reception state parameter of the data packet.

The apparatus for optimizing the transmission power in the wireless private simple network includes a power adjusting unit for adjusting the transmission power of the communication unit; And a memory for storing transmit power data for each slave.

When the control unit receives a data packet requesting transmission power adjustment through the communication unit, the controller updates the transmission power value of the corresponding slave stored in the memory according to the contents of the data packet requesting the transmission power adjustment, and transmits data to the slave. When transmitting a packet, a transmission power adjustment control signal is output to the power adjustment unit according to the updated transmission power value.

Preferably, the control unit controls the power measurement unit to measure the received power and the received link quality of the received data packet only when a message requesting measurement of transmission power is received through the communication unit.

In addition, the control unit preferably broadcasts a transmission power measurement request message at regular intervals in order to receive the transmission power adjustment request message.

Method for optimizing the transmission power in a wireless private simple network according to a first embodiment of the present invention for achieving the above object; Communication unit for transmitting and receiving data packet through the air, power measurement unit for measuring the power of the data packet received through the communication unit and communication between the corresponding slaves according to the contents of the data packet transmitted through the communication unit. A transmission power optimization method of a transmission power optimization apparatus including a control unit, comprising: receiving a data packet through the communication unit and receiving power parameter of the received data packet measured by the power measuring unit and a reception state parameter of the data packet Measuring a received link quality of a slave from the slave; And transmitting a transmit power adjustment request message to the slave according to the received link quality.

In the measuring of the reception link quality of the slave, it is preferable that the power measuring unit measures the reception power and the reception link quality of the received data packet only when a message requesting measurement of transmission power is received.

Method for optimizing the transmission power of a wireless private simple network according to a second embodiment of the present invention for achieving the above object; A control unit configured to communicate with slaves by controlling a master according to contents of a data packet transmitted through the communication unit, a communication unit for transmitting and receiving data packets through air, a power adjusting unit for adjusting transmission power of the communication unit, and the communication unit; A transmission power optimization method of a transmission power optimization apparatus comprising: receiving a message requesting transmission power adjustment through the communication unit; Updating a transmit power value for a corresponding slave in the memory according to the transmit power adjustment request message; And adjusting a transmission power through the power adjustment unit according to the updated transmission power value obtained from the memory and transmitting a data packet to the slave.

The control unit may further include broadcasting a transmission power measurement request message at a predetermined period in order to receive the transmission power adjustment request message.

In accordance with a third aspect of the present invention, there is provided a method for optimizing a transmission power of a wireless private simple network, by comparing connection information received from one slave with an allowable sensitivity, to determine a reference transmission power between a master and the slave. Determining; And optimizing the transmission power between the master and the remaining slaves.

The connection information is link quality information.

The reference transmission power determining step may include: verifying a current transmission power; initializing a slave counter variable (N); initializing a variable; recording a total number of slaves; receiving first link quality information receiving link quality information from an Nth slave; In a step of comparing the received link quality information with the allowable sensitivity in the first link quality information receiving step, and recording the current transmit power as the reference transmit power when the link quality information is equal to the allowable sensitivity in the first comparing step. A first transmission power recording step of proceeding to a transmission power optimization step, an increase adaptation step of obtaining a reference transmission power while increasing the current transmission power when the link quality information is smaller than the allowable sensitivity in the first comparison step, and a first comparison step If the link quality information is greater than the permissible sensitivity in the And a reduction step to obtain the transmission power adaptation.

The transmit power optimization step includes a variable increasing step of increasing a slave counter variable (N), a second link quality information receiving step of receiving link quality information from an Nth slave, and a fifth comparing the received link quality information with an allowable sensitivity In the comparison step, when the link quality information received from the Nth slave in the fifth comparison step is smaller than the allowable sensitivity, the third transmission power increase step, which proceeds to the second link quality information reception step after increasing the transmission power, compares fifth A second transmission power recording step of recording the reference transmission power recorded in the reference transmission power recording step as an adapted transmission power when the link quality information received from the Nth slave in step is greater than or equal to the allowable sensitivity; And comparing the total number of slave counter variables and slaves after performing the second transmission power recording step, and proceeding to the variable increasing step when the total number of slaves and the slave counter variable are different, and optimizing the transmission power when the total number of slaves and the slave counter variable are the same. It includes; the transmission power optimization confirmation step of terminating.

In accordance with another aspect of the present invention, there is provided a method for optimizing a transmission power of a wireless private simple network, comprising: selecting a slave for determining a transmission power according to connection information received from slaves constituting the private simple network; And determining the transmission power according to a result of comparing the connection information received from one slave determined in the slave selection step and the allowable sensitivity.

The slave selection step may include receiving connection information from each slave configuring the network; Determining an order of slaves according to strength of received connection information; And determining, as the slave for transmission power determination, the slave having the weakest strength of the connection information from the order of the slaves determined in the slave order determination step.

The transmission power determining step may include identifying a current transmission power; Comparing the connection information and the allowable sensitivity of the slave for determining the transmission power; A transmission power recording step of recording the current transmission power as an adapted transmission power when the connection information is equal to the allowable sensitivity in the comparing step; An increase adaptation step of obtaining an adapted transmit power while increasing the current transmit power when the connection information is smaller than the allowable sensitivity in the comparing step; And a reduced adaptation step of obtaining an adapted transmit power by reducing the current transmit power when the connection information is larger than the allowable sensitivity in the comparing step.

According to a fifth embodiment of the present invention, a method for optimizing a transmission power of a wireless private simple network when leaving a master includes: generating backup master information according to connection information received from slaves constituting the private simple network; A master departure detection step of detecting that the master has deviated from the private simple network; Determining a backup master according to the backup master order generated in the backup master information generation step; Determining a reference transmit power between the backup master and the slave; And optimizing the transmission power between the backup master and the remaining slaves.

In the reference transmission power determination step, the reference transmission power is the maximum transmission power. The transmit power optimization step finds the transmit power adapted to satisfy the allowable sensitivity while reducing the reference transmit power.

In the transmit power optimization step, the reference transmit power is the minimum transmit power. The transmit power optimization step finds the transmit power adapted to satisfy the allowable sensitivity while increasing the reference transmit power.

Using the method disclosed in the present invention, it is possible to optimize the transmission power between the master and the slave in the Bluetooth private simple network.

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

Referring to FIG. 1, the apparatus for optimizing a transmission power of a wireless private simple network according to the present invention includes a communication unit 10 including a transmitter 2 and a receiver 4, a power measurement unit 20, a power adjuster 30, The controller 40 and the memory 50 are included.

The communication unit 10 transmits or receives a data packet through air. The power measuring unit 20 measures the power of the data packet received through the receiving unit 4. The power adjuster 30 adjusts the transmit power of the transmitter 2. The memory 50 stores the transmit power values for the slaves . The control unit 40 includes a link quality measuring unit 32, a link quality comparing unit 34, and a power adjustment value determining unit 36. The link quality measuring unit 32 measures the link quality with a specific slave based on the received power of the data packet and the reception state parameter of the data packet measured by the power measuring unit 20. In this case, a data error rate, an error correction rate, a bandwidth loss, and a delay degree are used as a reception state parameter of a data packet used to measure a link quality with a slave. This measured link quality is defined here as the received link quality. The link quality comparison unit 34 compares the received link quality with a preset reference link quality to find the difference. The power adjustment value determiner 36 determines the increase or decrease of the transmit power to the slave according to the result value calculated by the link quality comparator 34. The control unit 40 broadcasts a packet of contents for requesting transmission power adjustment to the slave through the transmission unit 2 according to the power adjustment value determined by the power adjustment value determination unit 36.

In addition, the controller 40 may measure the reception power and the reception link quality of the data packet received by the power measurement unit 20 only when a message requesting measurement of the transmission power is received through the reception unit 4. have.

Meanwhile, when a data packet requesting transmission power adjustment is received through the communication unit 10, the controller 40 updates the transmission power value for the corresponding slave stored in the memory 50 according to the transmission power adjustment request. The controller 40 outputs a transmission power adjustment control signal reflecting the updated transmission power value to the power adjustment unit 30 during data packet transmission. The power adjuster 30 outputs the data packet with the adjusted transmit power according to the transmit power adjustment control signal output from the controller 40.

In addition, the controller 40 may broadcast the transmission power measurement request message at regular intervals in order to receive the transmission power adjustment request message.

Hereinafter, a method of optimizing transmission power in a wireless private simple network according to the present invention will be described with reference to FIGS. 2 to 8.

First, referring to FIG. 2, a transmission power optimization method of a wireless private simple network according to a first embodiment of the present invention will be described below.

The data packet is received through the receiver 4 (S1). The power measuring unit 20 measures the received power of the received data packet (S2). The reception link quality measurement unit 32 measures the reception link quality with the slave through the reception power measured by the power measurement unit 20 and the reception state parameter of the received data packet (S3). The link quality comparison unit 34 calculates a difference K between the measured numerical value of the received link quality and the predetermined numerical value of the reference link quality (S4). On the basis of the link quality comparison result value K calculated in the link quality comparison step S4, it is determined whether to request the increase or the decrease of the transmission power to the slave which transmitted the data packet (S5). The transmit power adjustment request message is transmitted to the slave according to the result determined in the transmit power increase or decrease determination step (S5) (S6).

The transmission power increase or decrease determination step (S5) is performed by the following detailed steps.

It is checked whether the absolute value | k | of the link quality comparison result value K is less than the set power adjustment unit size (S5-1). It is determined whether the link quality comparison result value k is greater than '0' (S5-2), and when satisfied, the transmission power with the slave is maintained as the current transmission power, and the transmission power optimization process ends. On the other hand, if the link quality comparison result value k is equal to or less than '0' (S5-2), the controller 40 transmits a transmission power increase request message to the slave (S6-2).

Meanwhile, the absolute value (| k |) of the link quality comparison result value K is equal to or larger than the set power adjustment unit size (S5-1), and the link quality comparison result value k is equal to or greater than '0' (S5-1a). If so, the controller 40 transmits a transmission power reduction request message to the slave (S6-1). However, if the link quality comparison result value k is less than or equal to '0', the controller 40 transmits a transmission power increase request message to the slave (S6-2).

In the above process, if the absolute value (| K |) of the link quality comparison result value (K) is greater than or equal to the set power adjustment unit size (S5-1), and the result value is greater than or equal to '0' (S5-1a), the absolute value The reduction request message will be sent to the slave (S6-1) until the value | k | is within the range of the set power adjustment unit.

In another embodiment, the reception power S2 and the reception link quality of the data packet may be measured (S3) only when a message for requesting measurement of the transmission power is received.

In another embodiment, if the master does not perform the above comparison step, but merely transmits the measurement result to the slave, the slave may perform the comparison step to adjust its power. However, in this case, since all the measurement result values transmitted from each master are calculated in one slave, performing the comparison step in each master has the effect of load balancing.

Referring to FIG. 3, a transmission power optimization method in a slave of a wireless private simple network according to a second embodiment of the present invention will be described below.

The slave checks whether the transmission power adjustment is impossible because the maximum or minimum transmission power is already set when the transmission power adjustment request is received (S11) from any one master (# 1) (S12). If it is determined in step S12 that transmission power adjustment is impossible, the transmission power adjustment impossible message is transmitted to the master # 1 that has made the transmission power adjustment request (S12-1). However, in step S12 of determining whether to adjust the transmission power, if transmission power adjustment is possible, the transmission power value of the previous state stored in the memory 50 is updated at the request of the master # 1 (S13). When the transmission power value update step S13 is completed, when the slave transmits the data packet to the master # 1, the slave transmits the data packet with the updated transmission power value (S14).

The method may further include broadcasting a transmission power measurement request message at a predetermined period in order to receive the transmission power adjustment request message.

In another embodiment, if it is impossible to adjust the transmission power separately as described above, the transmission power is adjusted based on the slave linked to the highest received power so as not to degrade the link quality with other slaves. When the transmit power reduction request is generated from slaves other than the reference slave, the master # 1 transmits a transmit power non-adjustment message to the slave requesting the transmit power reduction.

4 to 6, a transmission power optimization method between a master and a slave of a wireless private simple network according to a third embodiment of the present invention will be described below.

A transmission power optimization method between a master and a slave of a wireless private simple network according to the third embodiment of the present invention includes a reference transmission power determination step (S440) and a transmission power optimization step (S480). The reference transmission power determination step (S440) is a step of determining the reference transmission power between the master and the slave by comparing the connection information received from one slave and the allowable sensitivity (Q). The connection information may be information such as link quality information, direction, distance, etc. between the master and the slave, but the present invention will be described using link quality information as an example. The transmission power optimization step (S480) is a step for optimizing the transmission power between the master and the remaining slaves configuring the PAN.

The PAN manager of the master determines a reference transmit power by an HCI command called "Adapt_Transmit_Power" (S440). In the reference transmission power determination step (S440), the PAN manager first checks the current transmission power of the master using an HCI command called Read_Trnasmit_Power presented in the Bluetooth standard (S410). Next, a variable initialization step of initializing the slave counter variable N and recording the total number T of slaves configuring the current PAN is performed (S412). In describing the present embodiment, it is assumed that the initial value of the slave counter variable N is 1 and the total number T of slaves is 5. When the variable initialization step S412 is completed, the PAN manager performs a first link quality information reception step of receiving link quality information Link_Quality from the first slave in step S414. Next, a first comparison step of comparing the link quality information Link_Quality received in the first link quality information reception step S414 and the allowable sensitivity Q is performed (S416). Here, the permissible sensitivity Q is a predetermined value determined when constructing the piconet. The first comparison step S416 is branched into three cases according to the comparison result of the received link quality information and the allowable sensitivity.

<Case 1>

When the link quality information Link_Quality received from the first slave in the first comparing step S416 is equal to the allowable sensitivity Q, the current transmit power checked in the present transmit power checking step S410 is used as the reference transmit power. The first transmission power recording step (S418) of recording is performed, and the transmission power optimization step (S480) is performed.

<Case 2>

If the link quality information Link_Quality received from the first slave in the first comparing step S416 is smaller than the allowable sensitivity Q, the master increases the transmit power to the first slave by a predetermined amount while the reference transmit power RP Performs an incremental adaptation step of In the increase adaptation step, the master first performs a maximum transmit power comparison step S419 for comparing the current transmit power PP with the maximum transmit power MP. If the current transmit power PP and the maximum transmit power MP coincide in the maximum transmit power comparison step S416, it is indicated that the transmit power adaptation has failed and all processing ends (S427). In contrast, when the maximum transmit power PP and the maximum transmit power MP do not coincide in the maximum transmit power comparison step S416, the first transmit power is increased by a predetermined step based on the current transmit power PP. A transmission power increase step is performed (S420). When the first transmission power increase step S420 is completed, the master performs a first link quality information re-receive step of re-receiving link quality information Link_Quality from the first slave (S422). The second comparison step S424 compares the link quality information Link_Quality re-received from the first slave with the allowable sensitivity Q in the first link quality information re-receive step S422. In the second comparing step S424, when the re-received link quality information Link_Quality is smaller than the allowable sensitivity Q, the step of checking whether the upper limit of the transmission power compares the increased transmission power IP and the maximum transmission power MP. Perform (S426). If the current transmission power PP is not equal to the maximum transmission power MP in the step S426 of checking whether the transmission power is the upper limit, the process proceeds to the first transmission power increasing step S420. However, if the current transmission power PP is equal to the maximum transmission power MP in the step of checking whether the transmission power is the upper limit (S426), the process proceeds to the indication of adaptation failure (S427).

<Case 3>

When the link quality information Link_Quality received from the first slave in the first comparing step S416 is greater than the allowable sensitivity Q, the master obtains the reference transmit power RP while reducing the current transmit power PP. A reduction adaptation step S430 is performed. In the reduction adaptation step S430, the minimum transmission power determination step S431, the transmission power reduction step S432, the second link quality information re-reception step S433, the third comparison step S434, and the second transmission power increase are performed. Step S436 and a fourth comparison step S438 are included. The minimum transmission power determination step S431 compares the current transmission power PP with the minimum transmission power MinP, and when the current transmission power PP is equal to the minimum transmission power MinP, the first transmission power recording step S418. Proceed to). When the current transmission power PP is not equal to the minimum transmission power MinP in the minimum transmission power determination step S431, a transmission power reduction step S432 for reducing the transmission power to the Nth slave is performed. After the transmission power reduction step S432 is performed, a second link quality information re-reception step S433 for re-receiving link quality information from the N-th slave is performed. In the second link quality information re-receive step (S433), a third comparison step (S434) is performed in which the link quality information re-received from the Nth slave is compared with the allowable sensitivity. In the third comparing step S434, when the re-received link quality information is smaller than the allowable sensitivity Q, the reduced transmit power DP is increased and the second transmit power increasing step proceeds to the transmit power optimization step S480. (S436) is performed. If the link quality information re-received in the third comparison step S434 is not smaller than the allowable sensitivity Q, the current transmission power PP is compared with the minimum transmission power value MinP, and thus the current transmission power PP is minimum. In the case of the transmission power MinP, the fourth comparison proceeds to the reference transmission power recording step S418, and when the current transmission power PP is not equal to the minimum transmission power MinP, the fourth comparison proceeds to the transmission power reduction step S432. Step S438 is performed.

In the transmission power optimization step S480, the variable increase step S452, the second link quality information reception step S454, the fifth comparison step S456, the third transmission power increase step S458, and the second transmission power recording step (S460) and the transmit power optimization step (S462). That is, after the reference transmission power is determined, the slave counter variable N is increased to optimize transmission power with the remaining slaves (S452). Next, the master performs a second link quality information receiving step S454 of receiving link quality information Link_Quality from the Nth slave. The link quality information Link_Quality of the Nth slave received in the second link quality information receiving step S454 is compared with the allowable sensitivity Q (S456). When the link quality information Link_Quality of the Nth slave is less than the allowable sensitivity Q in the fifth comparison step S456, the master increases the transmission power to the Nth slave by a predetermined step and then receives the second link quality information. The third transmit power increasing step S458 proceeds to step S454. However, when the link quality information Link_Quality of the Nth slave is greater than or equal to the allowable sensitivity Q in the third transmit power increasing step S456, the reference transmit power RP is recorded as the adapted transmit power AP. (S460). After performing the transmission power recording step S460, a transmission power optimization checking step S462 is performed to check whether the adapted transmission power AP is optimized for all slaves. In the transmission power optimization check step (S462), the slave counter variable (N) is compared with the total number of slaves (T), and when the slave total number (T) and the slave counter (N) are different, the process proceeds to the variable increasing step (S452). When the total number of slaves T and the slave counter variable N are equal, the transmission power optimization step S480 ends.

The transmit power write step is performed by an HCI command called " Write_Transmit_Power ".

7, a transmission power optimization method for a wireless private simple network according to a fourth embodiment of the present invention will be described below.

A transmission power optimization method of a wireless private simple network according to a fourth embodiment of the present invention includes a slave selection step (S710) and a transmission power determination step (S730). Slave selection step (S710) is a step for selecting a transmission power determination slave according to the connection information received from each of the plurality of slaves constituting the private simple network. The slave selection step S710 is performed by the following detailed steps. First, step S712 of receiving connection information from each slave configuring the network is performed. The order of the slaves is determined according to the strength of the connection information received in the connection information receiving step (S712) (S714). From the order of the slaves determined in the slave order determination step (S714), the slave having the weakest strength of the connection information is determined as the slave for determining the transmission power (S716).

The transmission power determination step S730 determines the transmission power according to a result of comparing the connection information received from one slave determined in the slave selection step S710 and the allowable sensitivity. The transmission power determination step S730 includes the following detailed steps. First, the current transmission power is checked (S732). Next, the connection information and the allowable sensitivity of the slave selected in the transmission power determination slave determination step (S716) are compared (S734). When the connection information of the slave in the comparison step (S734) is equal to the allowable sensitivity (case I), the current transmission power is recorded as the adapted transmission power (S736). On the other hand, when the connection information of the slave is smaller than the allowable sensitivity (case II) in the comparison step (S734), the incremental adaptation step (S738) of obtaining the adapted transmission power while increasing the current transmission power is performed. On the other hand, when the connection information of the slave is larger than the allowable sensitivity (case III) in the comparison step (S734), the reduced adaptation step (S740) to reduce the current transmission power to obtain the adapted transmission power.

According to the fourth embodiment of the present invention, since the transmission power is optimized for the slave having the lowest strength of the received connection information, there is an advantage in that the reference transmission power setting step as in the third embodiment is not required.

Referring to FIG. 8, a method of optimizing a transmission power of a wireless private simple network at the time of master detachment according to the fifth embodiment of the present invention will be described.

The master periodically establishes the order of backup masters for the slaves during normal operation so that a new PAN can be configured by the remaining slaves even if the master deviates from the currently configured PAN. The transmission power optimization method of the private simple network at the time of master departure includes a backup master information generation step (S810), a master departure detection step (S820), a backup master determination step (S830), a reference transmission power determination step (S840), and a transmission power optimization step (S860). The backup master information generating step (S810) generates backup master information according to the connection information received from the slaves constituting the private simple network. In order to generate backup master information, the master receives connection information from each slave to verify that all slaves in the PAN are in radio communication range. The connection information may be Received Signal Strength Indication (RSSI) and / or Link Quality Information. The received signal strength is a value measured by the slave and informed to the master, which is closely related to the distance from the master. The link quality information is a value that can know the data error rate between the master and the slaves and is a value related to the distance between two devices and the presence of a shield. The slave can know the strength of the signal received from the master with the "Read-RSSI" HCI command defined in the Bluetooth standard. The slave can obtain the quality information of the link indicated by the number of 1 byte by using a standard HCI command called "Get_Link_Quality". The higher the value, the better the received signal strength and link quality information. The master determines the order of the backup masters in the order of the highest numerical value indicating received signal strength and / or link quality. This is because when the master is separated, the slave closest to the master needs to be the new master, so it is highly likely to reconfigure the PAN with the remaining slaves. The master transmits the determined order of backup masters to the slaves through the broadcast channel. The master reorders the backup masters at regular intervals because the positions of the slaves can be moved. If the master leaves the PAN due to exhaustion or artificial manipulation of the power supply, the PAN is reconfigured around the new master to replace the detached master according to the order of the backup master as described above.

After the backup master information is generated as described above, a master departure detection step (S820) of detecting that the master has detached from the private simplified network is performed. First, whether the master is disconnected from the already configured Bluetooth PAN is detected by detecting the disconnection between the master and the slaves. According to the Bluetooth standard version 1.0, Bluetooth-equipped devices can set a link supervision timer to check the connection status between specific periods (0.625 ms to 40.9 sec). If the result of the test is disconnected, it is reported to the host as a disconnection_complete event. The period for checking the connection with the master can be determined according to the value of the link supervision timer. The slave uses it to periodically check the connection with the master. If it is confirmed that the master has left the PAN, the backup master determination step (S830) is performed. The slaves assume the first backup master as a new master. The remaining slaves establish a connection with the new master to form a new PAN based on the new master. The new master establishes a connection with the rest of the slaves in the PAN and ensures that all are connected. If there is a slave that is not connected to the new master, the information of the disconnected slave is broadcasted to the connected slaves. If the first backup master is also detached, one of the slaves becomes a master of the newly configured PAN according to a predetermined order. When the new master is determined, the reference transmission power between the new master and the remaining slaves is determined (S840). In the reference transmission power determination step (S840), the reference transmission power may be the maximum transmission power or the minimum transmission power. If the reference transmit power is the maximum transmit power in the step S840 of determining the reference transmit power, the transmit power may be optimized to satisfy the allowable sensitivity while reducing the transmit power in a similar manner to the decrease adaptation step of the third embodiment. On the other hand, when the reference transmit power is the minimum transmit power, the transmit power may be optimized to satisfy the allowable sensitivity while increasing the transmit power in a manner similar to the increase adaptation step of the third embodiment.

The transmit power recording step records the current transmit power in any storage location in the Bluetooth module and is used as a reference value of increasing or decreasing the transmit power until the transmit power optimization step is completed.

Using the method disclosed in the present invention, it is possible to optimize the transmission power of a master and a slave in a wireless private simple network. Also. Even if the master fails, one of the backup masters can be set as a new master to form a new PAN and optimize the transmission power between the new master and the slaves. Therefore, by controlling the transmission power in the wireless private simple network, it is possible to reduce the transmission power consumption while maintaining an appropriate communication quality.

In the above, certain preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. will be.

1 is a block diagram showing an apparatus for optimizing a transmission power of a wireless private simple network according to the present invention;

2 is a flowchart illustrating a transmission power optimization method in a master of a wireless private simple network according to a first embodiment of the present invention;

3 is a flowchart illustrating a transmission power optimization method in a slave of a wireless private simple network according to a second embodiment of the present invention;

4 is a flowchart showing a transmission power optimization method of a wireless private simple network according to a third embodiment of the present invention;

FIG. 5A is a flowchart illustrating a detailed process of determining the minimum transmit power shown in FIG. 4; FIG.

FIG. 5B is a flowchart showing a detailed process of performing the reduction adaptation step shown in FIG. 4; FIG.

FIG. 6 is a flowchart illustrating a detailed process of performing the transmission power optimization step shown in FIG. 4; FIG.

7 is a flowchart showing a transmission power optimization method of a private simple network according to a fourth embodiment of the present invention; And

8 is a flowchart illustrating a transmission power optimization method of a private simple network according to a fifth embodiment of the present invention.

Explanation of symbols on main parts of drawing

2: transmitter 4: receiver

10: communication unit 20: power measurement unit

30: power adjustment unit 32: link quality measurement unit

34: link quality comparison unit 36: power adjustment value determination unit

40: control unit 50: memory

Claims (15)

In the system for controlling the transmission power of the transmitting device in a wireless network environment, A transmission device for transmitting a data packet including a transmission power measurement request message requesting transmission power measurement and controlling transmission power according to a transmission power adjustment request message received in response to the transmission power measurement request message; And When the data packet including the transmission power measurement request message is received, the reception power of the data packet of the transmission device is measured, and the data packet including the transmission power adjustment request message for controlling the transmission power of the transmission device is measured. A receiving device for generating and transmitting to the transmitting device; Including, The transmission power adjustment request message includes information on a difference between a link quality of the transmission device and a reference link quality stored in the reception device, which are determined using the reception power of the transmission device data packet. System to control the transmission power. The method of claim 1, The wireless network environment is a system for controlling the transmission power of a transmitting device, characterized in that the wireless LAN. The method of claim 1, And the link quality of the transmitting device is determined based on a reception power and a reception state parameter of the transmission device data packet. The method of claim 3, And the reception state parameter is measured using at least one of a data error rate, an error correction rate, a bandwidth loss, and a delay degree. The method of claim 1, The reference link quality comprises a reference transmit power of the receiving device. The method of claim 1, And the transmission power adjustment request message is a message requesting increase or decrease of transmission power of the transmission device. The method of claim 1, The transmission power adjustment request message further includes a power adjustment value determined by the difference between the link quality of the transmission device and the reference link quality. In the control method of the system for controlling the transmission power of the transmitting device in a wireless network environment, Transmitting a data packet including a transmission power measurement request message requesting transmission power measurement of the transmitting device from the transmitting device to a receiving device; Measuring a reception power of a data packet of the transmission device when the transmission power measurement request message is received; In response to the transmission power measurement request message, determining a link quality of the transmission device using the reception power of the transmission device data packet; Comparing the determined link quality of the transmitting device with a reference link quality stored in the receiving device to obtain a difference; Transmitting a data packet including a transmission power adjustment request message including the difference from the receiving device to the transmitting device; And   And controlling the increase or decrease of the transmit power of the transmitting device in accordance with the transmitted transmit power adjustment request message. The method of claim 8, And the wireless network environment is a wireless LAN. The method of claim 8, And determining a power adjustment value according to the difference between the link quality of the transmitting device and the reference link quality. The method of claim 8, And a link quality of the transmitting device is determined based on a reception power and a reception state parameter of the transmission device data packet. The method of claim 11, And the reception state parameter is measured using at least one of a data error rate, an error correction rate, a bandwidth loss, and a delay degree. The method of claim 8, And wherein the reference link quality comprises a reference transmit power of the receiving device. The method of claim 8, And the transmission power adjustment request message is a message requesting an increase or decrease of the transmission power of the transmission device. The method of claim 8, And the transmission power adjustment request message further comprises a power adjustment value determined according to a difference between the link quality of the transmission device and the reference link quality.