JP2010035068A - Wireless network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To monitor the communication quality of a communication route without interrupting normal data communication and to quickly select a more suitable communication route or frequency when detecting the degradation of the communication quality in a wireless network system using multi-hop wireless communication. <P>SOLUTION: The wireless network system 1 is configured by a base station 2 and a plurality of wireless terminals 3. The wireless terminal 3 acting as the base station 2 or a master station transmits communication control information for controlling a communication method of each slave station. A communication control part 11 in each wireless terminal 3 performs communication with its own master station and slave station by a communication method following the communication control information received from the master station, and simultaneously a communication quality measurement part 12 measures the communication quality of a communication route. The base station 2 evaluates the communication quality of each communication route 4 based on the communication qualities collected from a communication quality tabulation part 8 in each wireless terminal 3 to select an optimum communication route to be used for each wireless terminal 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a communication device such as a base station and a wireless terminal constituting a wireless network system represented by a wireless local area network (LAN), a wireless PAN (personal area network), etc., their management method, and wireless communication The present invention relates to a route control method.

  In recent years, wireless LANs, RFIDs, sensor networks, etc., including mobile phones, have been developed and spread, and many conveniences have been brought about. These wireless technologies are used not only in daily life but also in industrial fields. For example, wireless sensors are installed for the purpose of monitoring and controlling various devices in the plant.

  Data acquired by these various sensors is collected in a central operation room via a wireless network and used for management of the entire plant. Accordingly, in the operation of the plant, losing these sensor data may lead to a serious accident, and thus high reliability is required.

  However, in a plant, it is easily affected by fading due to complicated piping and metal facilities, and it is very difficult to perform stable wireless communication. In view of this, Patent Document 1, Patent Document 2, and the like disclose a method for reliably performing data communication by constantly measuring radio wave conditions that change from moment to moment and selecting an optimal communication path.

JP 2003-152786 A JP 2005-252496 A

  In these patent documents, in addition to normal data communication, the error rate and radio wave intensity between links are measured by periodically transmitting and receiving data for path quality measurement, and these measurement data are comprehensively measured. After evaluating the above, the method of selecting a more optimal route is taken.

  However, since data is transmitted and received to measure the quality of the wireless path, for example, when it is desired to transmit / receive sensor data in real time or when more sensor data is to be transmitted / received, the communication speed decreases or the delay increases. Etc. may occur.

  In these patent documents, it is premised that the network is configured using a single frequency. For example, there is no mention of a case where a plurality of frequencies are used simultaneously in order to improve communication reliability. .

  In view of the above problems of the prior art, the present invention uses the synchronization signal between the wireless terminals to monitor the entire wireless path for each frequency, and instructs switching to the selected path or frequency change by the synchronization signal. The purpose is to do.

  In order to achieve the above object, the present invention provides a wireless network system including a plurality of wireless terminals that are connected to each other by wireless signals and perform multi-hop communication, wherein the wireless terminal is connected to another adjacent wireless terminal. Communication quality measuring means for measuring the communication quality of the communication, communication quality aggregating means for sharing the communication quality information with other wireless terminals, and own communication according to the control information received from the other wireless terminals. Communication control means for controlling a route and communication time and generating control information to be transmitted to the other wireless terminal, wherein at least one of the wireless terminals manages overall communication of the wireless network system A communication quality evaluation unit that is a base station and numerically evaluates the communication quality shared by the communication quality aggregation unit to determine superiority or inferiority of a communication path; Route selection means for generating control information so that each of the wireless terminals constituting the wireless network system can select a communication route capable of communicating with the best communication quality, and measuring the communication quality and transmitting the control information It is characterized in that wireless communication is always performed using a communication path with good communication quality by periodically and simultaneously executing it repeatedly.

  According to the present invention, it is possible to suppress an increase in communication load due to a monitoring packet, and an optimum communication means is selected from a plurality of frequencies and communication paths so that normal data communication is not hindered at high speed. It is possible to switch.

  Hereinafter, embodiments of the present invention will be described as examples with reference to the drawings.

  Hereinafter, Example 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a wireless network system 1 according to an embodiment of the present invention. As shown in the figure, the wireless network system 1 includes a wireless terminal base station 2 (hereinafter abbreviated as a base station 2) and a wireless terminal 3.

  A plurality of base stations 2 and wireless terminals 3 may exist and perform data communication with each other wirelessly. Base stations 2 and wireless terminals 3 that cannot communicate directly transmit and receive data by multi-hop communication. As a connection form in multi-hop communication, a star type or tree type configuration may be used, or a mesh type capable of dynamically changing a route may be used. Here, it demonstrates as what can be mutually connected by the communication path | route 4 like FIG.

  As shown in FIG. 2, the base station 2 includes a processing unit 5, a storage unit 6, and a wireless communication unit 7. The processing unit 5 includes a CPU (Central Processing Unit) and the like, and by executing a program stored in the storage unit 6, processing of data transmitted to and received from the wireless communication unit 7, a communication quality totaling unit 8, communication quality described later, The functions of the evaluation unit 9, the route selection unit 10, and the communication control unit 11 are realized. The storage unit 6 functions to hold a program executed by the processing unit 5 and a work area of the processing unit 5.

  Note that the functions of the communication quality evaluation unit 9 and the route selection unit 10 in the processing unit 5 of the base station 2 may be executed by an external device such as a personal computer or a server connected to the base station via a network. The wireless communication unit 7 has a function of performing wireless data communication with other base stations 2 and wireless terminals 3, and a communication quality measuring unit 12 for measuring communication quality with the other base stations 2 and wireless terminals 3. And an antenna 13 for transmitting and receiving radio waves. Examples of communication quality to be measured include radio wave reception intensity, packet error rate, bit error rate, signal / noise ratio, data transfer rate, and the like.

  Similarly to the base station 2, the wireless terminal 3 includes a processing unit 5, a storage unit 6, and a wireless communication unit 7. The functions of the storage unit 6 and the wireless communication unit 7 are the same as those of the base station 2. The processing unit 5 includes a CPU (Central Processing Unit) and the like, and by executing a program stored in the storage unit 6, processing of data transmitted to and received from the wireless communication unit 7, a communication quality totaling unit 8, and a communication control unit 11. Realize the function. Accordingly, since the base station 23 can operate as the wireless terminal 3, the illustration of the wireless terminal 3 is omitted.

  In this specification, in multi-hop communication, the wireless terminal 3 connected on the side close to the base station 2 is defined as the parent station, and conversely, the wireless terminal 3 communicating on the side far from the base station 2 is defined. Is defined as a slave station. In addition, “upper” or “upstream” of communication means that the data transmission direction is toward the base station, and “lower” or “downward” means that the data transmission direction is opposite to the base station. Suppose that

  Therefore, in the network configuration of FIG. 1, the base station 2 is always a master station, and in this case, the radio terminal 3 </ b> A and the radio terminal 3 </ b> B are slave stations of the base station 2. When the wireless terminal 3A or the wireless terminal 3B is a master station, the wireless terminal 3C and the wireless terminal 3D are slave stations.

  The communication quality totaling unit 8 has a function of storing data of communication quality measured by the communication quality measuring unit 12 in the time series in the storage unit 6 and transmitting the data to the master station by the wireless communication unit 7 at a predetermined timing. In addition, when the mobile station itself is a master station, the communication quality data transmitted from the slave station is stored in the storage unit 6 and transmitted to a higher-order master station at a predetermined timing.

  Therefore, time series data of communication quality of all routes in the wireless network system 1 is collected in the base station 2 by the function of the communication quality totaling unit 8. The communication quality evaluation unit 9 has a function of storing data related to communication quality collected in the base station 2 in the storage unit 6 and numerically evaluating the communication state of all routes of the wireless network system 1.

  Based on the evaluation result of the communication quality evaluation unit 9, the route selection unit 10 determines a communication route 4 on which each wireless terminal 3 can realize data communication most effectively. The communication control unit 11 generates communication control information according to the determination of the route selection unit 10 and transmits the communication control information to the slave station via the wireless communication unit 7. The communication control information includes the communication path of the slave station, information for synchronizing communication, and the like, details of which will be described later.

  A process for selecting the communication path 4 of the base station 2 or the wireless terminal 3 in the wireless network system 1 will be described in detail with reference to the flowchart of FIG.

  First, the base station 2 transmits communication control information to the slave station (process 301). Next, the slave station that has received the communication control information measures the communication quality of the route and saves it in the storage unit 6 or adds it to the data addressed to the master station by the communication quality totaling unit 8 (process 302). ). Here, the slave station may return response data to the master station to indicate that the communication control information has been correctly received. In this case, if there is no response from the slave station, the master station repeats the retransmission process a predetermined number of times (process 303). The master station can also measure the quality of the communication path 4 based on the response data from the slave station. Next, the wireless terminal 3 that has received the communication control information transmits data to its own master station or slave station according to the method defined by the communication control information (process 304). The data may be general user data or control data such as communication control information. The slave station or master station that has received the data measures the communication quality in the same manner as in the process 302 (process 305). Further, with respect to this data, the retransmission process may be repeated a predetermined number of times as in the process 303 (process 306).

  As described above, by repeating the processing from processing 301 to processing 306 a predetermined number of times or for a predetermined time, the communication quality of each path is collected in the base station 2 (processing 307). Therefore, the communication quality evaluation unit and the route selection unit of the base station 2 evaluate the communication quality of all the routes of the wireless network system 1 and select the optimum communication route 4 (processing 308). Details of the communication quality evaluation method and the optimum communication path 4 selection method will be described later. If it is necessary to change the currently used communication path 4 (process 309), the path change information is added to the communication control information to be transmitted next (process 310). Thereafter, by repeatedly executing the processing from the processing 301 again, in the wireless network system 1, the wireless terminals 3 always select a route with good communication quality and communicate with each other.

  Hereinafter, the flow of communication data in the wireless network system 1 of the present invention will be described in detail with reference to FIG. As an example, as shown in FIG. 4A, the base station 2 is connected to the wireless terminal 3A and the wireless terminal 3B as the slave stations, the wireless terminal 3A is connected to the wireless terminal 3C as the slave station, It is assumed that it is connected to a wireless terminal 3D that is a slave station. The address of the base station 2 is set to 00, and the addresses of the wireless terminal 3A, the wireless terminal 3B, the wireless terminal 3C, and the wireless terminal 3D are set to 01, 02, 03, and 04, respectively.

  First, the base station 2 transmits communication control information to the wireless terminal 3A and the wireless terminal 3B (process 401). This communication control information is composed of, for example, a data frame 50 (hereinafter abbreviated as frame 50) as shown in FIG. The communication control information may be individually transmitted to the wireless terminal 3A and the wireless terminal 3B by unicast communication, or may be simultaneously transmitted to the wireless terminal 3A and the wireless terminal 3B by broadcast communication. FIG. 5 shows an example of the frame 50 when performing unicast communication, and FIG. 6 shows an example of the frame 50 when performing broadcast communication.

  Examples of information included in the header information of the frame 50 include a start code, type, frame length, sequence number, number of retransmissions, and the like. Examples of information included in the footer information include redundancy codes such as CRC, end codes, and the like. The order and size of data in the frame 50 are not particularly limited, and may include information related to other existing technologies. The slave station address is set as the destination address, and its own address is set as the source address.

  In addition, the timing at which the slave station performs data transmission, for example, the transmission start time and the allocated transmission time is set in the synchronization information. As an example, in the frame 51, for the wireless terminal 3A, the time for starting data transmission is set to 0, and the allocated time for data transmission is set to 2.

  The start time may be a relative time based on the time when the communication control information is received, or an absolute time may be used. However, when the absolute time is used, the wireless terminal 3 has means for knowing the time, for example, a real time clock.

  In addition, although a simple integer value is used here to set a random value, in practice, the time for the frame 50 to propagate in the air, the data processing time, the retransmission time for the frame 50, and the like are considered. Values may be set in detail. A plurality of patterns may be set for the start time and the allocation time according to the type of the frame 50 and the like.

  Furthermore, a method may be used in which time slots are defined in advance at a predetermined time without using the start time and the assigned time, and the order of the time slots is set. Information related to the communication path 4 of the slave station is set in the path information.

  For example, as in the frame 50 of FIG. 5, the addresses of all the slave stations and whether or not the route is valid are set. In this example, the route information of all the slave stations is set. However, a method may be used in which each wireless terminal 3 individually holds information on the communication route 4 and sets only the difference when the route is changed.

  As shown in FIG. 6, the basic structure of the broadcast frame 50 is the same as that of unicast. However, a broadcast address such as FF is set as the transmission destination address, and synchronization information and path information are set as the data table 60 for each address of the slave station. In the broadcast, the number of transmissions of the frame 50 is suppressed as compared with the unicast, but the length of one frame 50 is increased.

  Hereinafter, unicast communication will be described as an example, but the same can be realized by broadcasting.

  The wireless terminal 3 that has received the communication control information from the base station 2 through the process 401 transmits data at a timing according to the synchronization information. For example, the wireless terminal 3A executes data transmission addressed to the base station 2 (process 402) and transmission of communication control information to the slave station (process 403) within the allocated time. The data transmission in the process 402 and the process 403 may be in the reverse order, may be performed together by broadcast transmission, or may be performed multiple times within the allocated time.

  As shown in FIG. 7, the data addressed to the master station in process 402 is added with the communication quality of the path measured by itself and the information of the communication quality measured by the slave station. For example, as shown in FIG. 7A, the communication quality of all routes is added. Alternatively, as shown in FIG. 7B, even if the data transmission directions are different, regarding the communication quality of the same route, the average value is added, or one of the communication qualities is added.

  In the communication control information shown in the frame 51, the wireless terminal 3A is set to 2 as the communication allocation time, and the wireless terminal 3C is set as an effective slave station. Therefore, in the communication control information from the wireless terminal 3A to the slave station, for example, as shown in a frame 53, the start time is set to 1 and the allocated time is set to 1 for the wireless terminal 3C.

  For the route information of the frame 53, nothing is set because the target wireless terminal 3C has no slave station. In data transmission from the wireless terminal 3A to the wireless terminal 3C in the process 403, the communication control information and the general data may be transmitted together or may be divided and transmitted. Next, the wireless terminal 3C that has received the communication control information from the wireless terminal 3A transmits data to the master station according to the set start time and assigned time, similarly to the process 402 (process 404).

  Thereafter, the same applies to the wireless terminal 3B and the wireless terminal 3D. For example, the wireless terminal 3B that has received the communication control information as shown in the frame 52 performs data transmission to the master station (process 405) and communication control information or data transmission to the slave station (process 406). The communication control information to the slave station is set as a frame 54, for example. Thereafter, the wireless terminal 3D performs data transmission to the parent (process 407).

  As described above, information regarding communication quality is collected in the base station 2 from each wireless terminal 3 in the process of repeatedly executing transmission and reception of data. The base station 2 evaluates the communication quality of the entire route and selects a better communication route 4.

  For example, it is assumed that the base station 2 changes the communication path 4 between the wireless terminal 3D and the master station as shown in FIG. The data flow in this case will be described with reference to FIG.

  First, for example, the base station 2 sets communication control information like the frame 55 and the frame 56 and transmits the communication control information to the wireless terminal 3A and the wireless terminal 3B (process 408).

  The wireless terminal 3A transmits data to the master station based on the received communication control information (process 409).

  Further, the communication control information is set and transmitted, for example, as in the frame 53 and the frame 57, to the two slave stations, the wireless terminal 3C and the wireless terminal 3D (process 410 and process 412).

  Next, the wireless terminal 3C and the wireless terminal 3D similarly execute data transmission to the master station (processing 411, processing 413). Here, the processing 410 to the processing 413 may be executed a plurality of times within the range of 3 which is the allocation time set by the frame 55, and the order may be arbitrary.

  Finally, the wireless terminal 3B performs data transmission to the master station (process 414), but since there is no valid slave station, communication control information is not transmitted.

  As described above, the wireless network system 1 measures and evaluates communication quality, and performs optimal route selection. Hereinafter, a communication quality evaluation method and an optimum route selection method will be described in detail with reference to FIGS.

  The base station 2 collects route quality information sent from each wireless terminal 3. For example, as shown in FIG. 8, the communication quality between the base station 2 and the radio terminal 3A is 4, the communication quality between the radio terminal 3A and the radio terminal 3C is 2, and the base station 2 and the radio terminal 3C are Suppose that the communication quality between them is 6. Similarly, the communication quality of other routes is as shown in FIG. The communication quality value may be anything as long as the quality of each communication path 4 can be compared numerically.

  Here, for example, the value of communication quality is handled as the error rate in the route. That is, the base station 2 and the wireless terminal 3A are defined as communicating with an error rate of 4%. The error rate may be simply the error rate of the frame 50 or the bit error rate. As described above, the communication quality may be a value derived based on the received radio wave intensity, the S / N ratio, or the like.

  In this way, the communication quality evaluation unit 9 of the base station 2 first defines the communication quality per hop of each route (processing 901).

  Next, the communication quality evaluation unit 9 calculates the communication quality in multi-hop communication, that is, the total communication quality of all routes from each wireless terminal 3 to the base station 2 (process 902). For example, the data arrival rate when data is transmitted from the wireless terminal 3C to the base station 2 is calculated as follows. Here, the data arrival rate is defined as an establishment in which data is transmitted without error, that is, “100−error rate (%)”. Further, the case of transmitting data via the wireless terminal 3A is abbreviated as “route C → A → base”.

In the route C⇒A⇒group, (100-2) × (100-4) ÷ 100 = 94.08%.
In the route C⇒B⇒group, (100-3) × (100-3) ÷ 100 = 94.09%.
In the route C => group, (100-6) = 94%.

  Similarly, the data arrival rate from the wireless terminal 3D to the base station 2 is calculated as follows.

In the route D⇒A⇒group, (100-4) × (100-4) ÷ 100 = 92.16%.
In the route D⇒B⇒group, (100-2) × (100-3) ÷ 100 = 95.06%.
In the route D => group, (100-8) = 92%.

  Similarly, the communication quality evaluation unit 9 calculates communication quality for all routes, and from the result, the route selection unit 10 selects the communication route 4 with the highest data arrival rate (process 903). For example, the route between the wireless terminal 3C and the base station 2 is “route C → B → base”, and the route between the wireless terminal 3D and the base station 2 is “route D → B → base”. Here, since the wireless terminal 3B is used on either route, there is a concern about an increase in processing load on the wireless terminal 3B.

  Therefore, when there are overlapping routes or wireless terminals 3 in the selected route, the route may be selected in consideration of the influence (processing 904). For example, if there is an overlapping route, it is determined whether or not another route exists as a candidate (processing 905), and if the candidate is a sufficiently good route, it is selected (processing 906). As a criterion for the process 906, a predetermined value may be set in advance in the communication quality evaluation unit 9, or an average value, a standard deviation, or the like may be obtained and a threshold value may be set based on those values.

  In this example, when data is transmitted from the wireless terminal 3C to the base station 2, a high data arrival rate can be realized even if “route C → A → base” is equivalent to “route C → B → base”.

  Therefore, “route C → A → group” may be selected again instead of “route C → B → group” where the routes overlap (processing 903).

  Finally, if there is no problem with the selected route, the route is determined as a valid route (process 907). Here, in the process 902, some weighting is performed so that a route with a small number of hops, that is, a route “Route C⇒Base” or “Route D⇒Base” is selected with higher priority when evaluating each route. May be performed. Moreover, when evaluating the route, the data arrival rate is used here as an example, but it may be performed by simple numerical processing. For example, there is a method of simply adding or multiplying as follows and selecting a route having a small numerical value.

In the route C⇒A⇒group, 4 + 2 = 6 (addition) or 4 × 2 = 8 (multiplication)
In the route C⇒B⇒ group, 3 + 3 = 6 (addition) or 4 × 2 = 8 (multiplication)
6 (addition) or 6 (multiplication) in the route C⇒ group

  Thus, the base station 2 can select the optimum communication path 4 by the communication quality evaluation unit 9 and the path selection unit 10 based on the aggregated communication quality. As described above, according to the present embodiment, in the wireless network system 1, it is possible to measure the communication quality between the wireless terminals 3 at regular intervals and always perform data communication using the optimal communication path 4. .

  Hereinafter, Example 2 of the present invention will be described in detail with reference to the drawings.

  The configuration example of the wireless network system 1 according to the embodiment of the present invention is the same as that shown in FIG.

  As shown in FIG. 10, the base station 2 in this embodiment includes a processing unit 5, a storage unit 6, and a wireless communication unit 7. The processing unit 5 includes a CPU (Central Processing Unit) and the like, and by executing a program stored in the storage unit 6, processing of data transmitted to and received from the wireless communication unit 7, a communication quality totaling unit 8, a communication quality evaluation unit 9. The functions of the route selection unit 10, the communication control unit 11, and the frequency selection unit 14 are realized. The storage unit 6 functions to hold a program executed by the processing unit 5 and a work area of the processing unit 5.

  The functions of the communication quality evaluation unit 9, the route selection unit 10 and the frequency selection unit 14 in the processing unit 5 of the base station 2 may be executed by an external device such as a personal computer or a server connected to the base station via a network. good.

  The wireless communication unit 7 has a function of performing wireless data communication with other base stations 2 and wireless terminals 3, and a communication quality measuring unit 12 for measuring communication quality with the other base stations 2 and wireless terminals 3. , An antenna 13 for transmitting and receiving radio waves and a frequency switching unit 15 for switching the frequency of wireless communication.

  Similarly to the base station 2, the wireless terminal 3 includes a processing unit 5, a storage unit 6, and a wireless communication unit 7. The functions of the storage unit 6 and the wireless communication unit 7 are the same as those of the base station 2. The processing unit 5 includes a CPU (Central Processing Unit) and the like, and by executing a program stored in the storage unit 6, processing of data transmitted to and received from the wireless communication unit 7, a communication quality totaling unit 8, and a communication control unit 11. Realize the function. Accordingly, since the base station 2 can operate as the wireless terminal 3, the illustration of the wireless terminal 3 is omitted.

  The communication quality totaling unit 8 has a function of storing communication quality data measured by the communication quality measuring unit 12 for each frequency in the time series in the storage unit 6 and transmitting the data to the master station by the wireless communication unit 7 at a predetermined timing. . In addition, when the mobile station itself is a master station, the communication quality data transmitted from the slave station is stored in the storage unit 6 for each frequency, and transmitted to a higher-order master station at a predetermined timing. Therefore, the function of the communication quality totaling unit 8 collects time-series data related to the communication quality for each frequency of all routes in the wireless network system 1 to the base station 2.

  The communication quality evaluation unit 9 has a function of storing data related to communication quality collected in the base station 2 in the storage unit 6 and numerically evaluating the communication state of all routes of the wireless network system 1 for each frequency.

  Based on the evaluation result of the communication quality evaluation unit 9, the route selection unit 10 determines a communication route 4 on which each wireless terminal 3 can realize data communication most effectively. The frequency selection unit 14 determines a frequency at which each wireless terminal 3 is least susceptible to radio wave interference based on the evaluation result of the communication quality evaluation unit 9.

  The communication control unit 11 generates communication control information according to the determination of the route selection unit 10 and the frequency selection unit 14 and transmits the communication control information to the slave station via the wireless communication unit 7. The communication control information includes information for synchronizing the communication path and communication of the slave station, information on the frequency to be used, and the like, which will be described in detail later.

  In the wireless network system 1 of the present embodiment, a process for selecting a frequency to be used with the communication path 4 of the base station 2 or the wireless terminal 3 will be described in detail with reference to the flowchart of FIG.

  First, the base station 2 or the wireless terminal 3 sets a frequency to be used (process 1101). Here, the base station 2 determines the frequency by the frequency selector 14. However, at first, a predetermined pattern and a frequency to be used at random are determined. The wireless terminal 3 determines the frequency according to the communication control information received from the master station.

  Next, the base station 2 or the wireless terminal 3 transmits data to the master station or the slave station (process 1102).

  The slave station or master station that has received the data measures the communication quality of the route, and saves it in the storage unit 6 or adds it to the data addressed to the master station by the communication quality totaling unit 8 (process 1103).

  Here, the receiving side may return response data to indicate that the data has been correctly received, and if the transmitting side cannot receive the response data, the retransmission process may be repeated a predetermined number of times (process 1104). In this case, the transmission side can also measure the quality of the communication path 4 by receiving the response data.

  As described above, the base station 2 and the wireless terminal 3 communicate with each other while changing the frequency, and the communication quality for each frequency of each path is collected in the base station 2 by repeating a predetermined number of times or a predetermined time (processing 1105). ).

  Therefore, the communication quality evaluation unit, the route selection unit, and the frequency selection unit of the base station 2 evaluate the communication quality for every frequency of all the routes, and select the optimum communication route 4 and frequency (processing 1106). Details of the communication quality evaluation method and the optimum communication path 4 and frequency selection method will be described later.

  When the master station needs to change the currently used communication path 4 or frequency (process 1107), it adds path change information or frequency information to be used to communication control information to be transmitted next (step 1107). Process 1108).

  Thereafter, by repeatedly executing the processing from the processing 1101, in the present embodiment, each wireless terminal 3 always selects a path and frequency with good communication quality and communicates with each other.

  Hereinafter, the flow of communication data in the present embodiment will be described in detail with reference to FIG. As an example, as shown in FIG. 12, the base station 2 is connected to the wireless terminals 3A and 3B that are slave stations, the wireless terminal 3A is connected to the wireless terminal 3C that is a slave station, and the wireless terminal 3B is a slave station. It is assumed that it is connected to a certain wireless terminal 3D. The address of the base station 2 is set to 00, and the addresses of the wireless terminal 3A, the wireless terminal 3B, the wireless terminal 3C, and the wireless terminal 3D are set to 01, 02, 03, and 04, respectively.

  First, the base station 2 transmits communication control information to the wireless terminal 3A (process 1201). This communication control information is composed of, for example, a frame 130 as shown in FIG. As in the case of the first embodiment, the communication control information may be individually transmitted to the wireless terminal 3 by unicast communication, or may be simultaneously transmitted to a plurality of wireless terminals 3 by broadcast communication. FIG. 13 shows an example of a frame 130 when unicast communication is performed. The header information, footer information, transmission destination address, transmission source address, synchronization information, and path information of the frame 130 are the same as those of the frame 50 in the first embodiment.

  FIG. 14 shows a frame 130 by broadcasting. The basic structure is the same as in the case of unicast, but a broadcast address such as FF is set as the destination address, and the frequency, synchronization information, and path information are set as the data table 60 for each slave station address. .

  Here, an example in which unicast communication is performed will be described. The frequency used by the wireless terminal 3 that has received the communication control information is set as the master station frequency. The frequency used by the connected slave station is set as the frequency of the slave station in the path information.

  Therefore, there is no need to set whether the connection with the slave station in the route information is valid or invalid. That is, it may be valid if it is the same frequency as the master station, and invalid if it is a different frequency.

  The wireless terminal 3 that has received the frame 131 as communication control information from the base station 2 through the process 1201 sets its own frequency to 1, and transmits data at a timing according to the synchronization information.

  For example, the wireless terminal 3A executes data transmission (process 1202) addressed to the base station 2 and transmission of communication control information to the slave station (process 1205) within the allocated time. The data transmissions of the processing 1202 and the processing 1205 may be performed in reverse order, may be performed collectively by broadcast transmission, or may be performed a plurality of times within the allocated time.

  In the processing 1202, the data addressed to the master station is added with the communication quality of the path measured by itself and information of the communication quality measured by the slave station in the same manner as in the first embodiment. However, information on the used frequency is also added to the communication quality information.

  In the communication control information shown in the frame 131, the wireless terminal 3A is set to 2 as the communication allocation time, and the wireless terminal 3C is set as a slave station of the same frequency. Therefore, in the communication control information from the wireless terminal 3A to the slave station, for example, as shown in a frame 133, the start time is set to 1 and the allocated time is set to 1 for the wireless terminal 3C.

  For the route information of the frame 53, nothing is set because the target wireless terminal 3C has no slave station. 1 is set as the master station frequency. In data transmission from the wireless terminal 3A to the wireless terminal 3C in the process 1205, the communication control information and the general data may be transmitted together or may be transmitted separately.

  Next, the wireless terminal 3C that has received the communication control information from the wireless terminal 3A transmits data to the master station according to the set frequency, start time, and allocated time, similarly to the process 1202 (process 1206).

  Thereafter, the same applies to the wireless terminal 3B and the wireless terminal 3D. For example, the wireless terminal 3B that has received the communication control information as shown in the frame 132 performs data transmission to the master station (process 1204) and communication control information or data transmission to the slave station (process 1207).

  The communication control information to the slave station is set as a frame 134, for example. Thereafter, the wireless terminal 3D performs data transmission to the parent (process 1208). Here, for example, the processing 1203 to the processing 1204 and the processing 1205 to the processing 1206 use different frequencies, so that they may be executed simultaneously, that is, the start times may be the same.

  Next, a data flow when the wireless terminal D changes the parent station from the wireless terminal B to the wireless terminal C and changes the frequency from 1 to 2 by the determination of the base station 2 will be described.

  First, similarly to the process 1201, the base station 2 transmits communication control information as shown in the frame 135 to the wireless terminal A (process 1209).

  Similarly to the processing 1202 and the processing 1205, the wireless terminal A performs data transmission to the base station 2 (processing 1210) and transmission of communication control information or general data (processing 1207) to the wireless terminal C.

  The wireless terminal D transmits data to the wireless terminal A, which is the master station, in the same manner as in the process 1206 (process 1212). Here, as shown in the frame 135, the wireless terminal A recognizes that it is connected to the wireless terminal D at the address 04 at the same frequency 1 as itself.

  Accordingly, the wireless terminal A transmits communication control information as shown in the frame 137, for example, to the wireless terminal D (process 1215). Thereafter, the wireless terminal D transmits data to the wireless terminal A of the master station (process 1216).

  Here, as with the wireless terminal A, the base station transmits communication control information as shown in the frame 136, for example, to the wireless terminal B using the frequency 2 (process 1213).

  Since there is no slave station that communicates with the same frequency 2 as that of the wireless terminal B, the wireless terminal B performs communication only with the base station (process 1214).

  Here, for example, the processing 1211 to processing 1212 and the processing 1213 to processing 1214 use different frequencies, so that they may be executed simultaneously, that is, the start time may be the same. Similarly, processing 1209 to processing 1210 and processing 1207 to processing 1208 may be executed simultaneously.

  In this description, only one frequency is set in the communication control information for the sake of simplicity. However, a method may be used in which a plurality of frequencies are set and selected sequentially or randomly.

  Further, when instructing the frequency change, the target wireless terminal 3, in this example, the wireless terminal D at address 04, is notified in advance of the change as shown in the frame 131 and the frame 132 (2⇒1). By performing this, the frequency can be changed at high speed. In other words, in the process 1215, if the wireless terminal D does not know in advance that the frequency has been changed from 2 to 1, it takes extra time to scan the frequency.

  As described above, in this embodiment, the communication quality is measured and evaluated while changing the frequency, and the optimum path and frequency are selected for communication.

  Hereinafter, a communication quality evaluation method and an optimum route and frequency selection method will be described in detail.

  First, as a first method, there is a method in which the evaluation of the communication path shown in FIGS. 8 and 9 of the first embodiment is performed for each frequency, and the optimum path and frequency are selected. In addition, for example, there are methods as shown below.

  It is assumed that each wireless terminal 3 measures the interference power at each frequency by the communication quality measuring unit 12 while periodically changing the frequency by the frequency switching unit 15 when the wireless terminal 3 is not performing data communication.

  For example, as the communication quality, an interference power distribution 150 for each frequency and time is measured as shown in FIG.

  In this figure, when a frequency is changed in four steps (F = 1 to 4) in a certain wireless terminal 3, the interference power P for each time (T = 0 to 3) is shown in each frequency. For example, the interference power P = 10 at the time T = 0 at the frequency F = 1. Here, the interference power at frequency F = f (f = 0 to 4) and time T = t (t = 0 to 3) is P (f, t).

  That is, P (1, 0) = 10. However, the time T is not an absolute time and may be a measured order. In this example, it is assumed that time T = 0 is the oldest measurement point and time T = 3 is the latest measurement point.

  Further, the frequency is assumed to be frequency bands adjacent to each other in order from F = 1 to 4. That is, the frequency F = 1 and the frequency F = 2 are the most adjacent, and the frequency F = 1 and the frequency F = 4 are the farthest frequencies. Similarly, it is assumed that the frequency F = 2 and the frequency F = 3, and the frequency F = 3 and the frequency F = 4 are adjacent to each other.

  When an interference power distribution 150 as shown in FIG. 15 is given, first, an interference degree 151 considering the passage of time for the frequency F = 1 is obtained. For example, the interference degree is calculated by placing more emphasis on the newly measured interference power than the interference power measured in the past. When it is assumed that the degree of interference 152 considering the passage of time at the frequency F = f is It (f), It (f) is defined by the following equation (1).

  In equation (1), α (t) is a weight related to time. For example, if α (0) = 0, α (1) = 1, α (2) = 2, α (3) = 3, the past Therefore, the new interference power is more important than the interference power. FIG. 15 shows the result of calculating the interference degree from the frequency F = 1 to 4 according to the equation (1). That is, It (1) = 41, It (2) = 10, It (3) = 39, It (4) = 31.

  In response to this result, the frequency F = 2 may be selected as the frequency with the least radio wave interference. Further, as shown below, an interference degree 152 that takes into consideration the interference power of adjacent frequencies may be used. The interference degree in this case is defined as If (f) and is defined by the following equation (2).

  In Expression (2), i represents the degree of adjacency with respect to the frequency F = f. That is, if i = −1 with respect to f = 2, the adjacent frequency f = 2−1 = 1 is indicated. Similarly, for f = 2, if i = 1, the frequency f = 2 + 1 = 3 is indicated. However, if i = 0, it indicates its own frequency, and i = -2 and i = 2 are invalid because there is no corresponding frequency in this example, and the value is calculated as 0.

  Further, β (i) is a weighting for the interference degree of adjacent frequencies. For example, β (0) = 1, β (−1) = β (1) = 0.5, β (−2) = β (2 ) = 0.1, the closer the interference frequency, the greater the influence. In this case, the result of calculating the interference 152 for the frequency F = 1 to 4 is shown in FIG.

  That is, If (1) = 64.4, If (2) = 53.1, If (3) = 63.6, If (4) = 51.5. Accordingly, when taking into account the degree of interference between adjacent frequencies, the frequency F = 4 can be selected as the frequency with the least interference. The numerical values used in this example are merely examples, and there are no particular restrictions on the type and number of frequencies and the number of times.

  Thus, based on the interference power measured in each wireless terminal 3, an optimum frequency in that wireless terminal 3 can be selected. According to the present embodiment, in the wireless network system 1, it is possible to measure the communication quality between the wireless terminals 3 at a fixed period and always perform data communication using the optimal communication path 4 and frequency. .

  Hereinafter, Example 3 of the present invention will be described in detail with reference to the drawings.

  The configuration example of the wireless network system 1 according to the embodiment of the present invention is the same as that shown in FIG.

  As shown in FIG. 16, the base station 2 in this embodiment includes a processing unit 5, a storage unit 6, and a plurality of wireless communication units 7. The processing unit 5 includes a CPU (Central Processing Unit) and the like, and by executing a program stored in the storage unit 6, processing of data transmitted to and received from a plurality of wireless communication units 7, a communication quality totaling unit 8, a communication quality The functions of the evaluation unit 9, the route selection unit 10, the communication control unit 11, and the frequency selection unit 14 are realized.

  The storage unit 6 functions to hold a program executed by the processing unit 5 and a work area of the processing unit 5. The wireless communication unit 7 has the same function as the wireless communication unit 7 in the second embodiment. However, the frequency switching unit may not be provided. Note that the functions of the communication quality evaluation unit 9 and the route selection unit 10 in the processing unit 5 of the base station 2 may be executed by an external device such as a personal computer or a server connected to the base station via a network.

  Similar to the base station 2, the wireless terminal 3 includes a processing unit 5, a storage unit 6, and a plurality of wireless communication units 7. The functions of the storage unit 6 and the wireless communication unit 7 are the same as those of the base station 2. The processing unit 5 includes a CPU (Central Processing Unit) and the like, and by executing a program stored in the storage unit 6, processing of data transmitted to and received from the wireless communication unit 7, a communication quality totaling unit 8, and a communication control unit 11. Realize the function.

  Accordingly, since the base station 2 can operate as the wireless terminal 3, the illustration of the wireless terminal 3 is omitted. Since the base station 2 and the wireless terminal 3 of this embodiment have a plurality of wireless communication units 7, if each wireless communication unit uses a different frequency, it is possible to communicate with the plurality of wireless terminals 3 at the same time. .

  The communication quality totaling unit 8 stores the communication quality data measured for each frequency by the communication quality measuring unit 12 of the plurality of radio communication units 7 in the time series in the storage unit 6 and any one of the radio communication units at a predetermined timing. 7 has a function of transmitting to the master station.

  In addition, when the mobile station itself is a master station, the communication quality data transmitted from the slave station is stored in the storage unit 6 for each frequency, and transmitted to a higher-order master station at a predetermined timing.

  Therefore, the function of the communication quality totaling unit 8 collects time-series data regarding the communication quality for each frequency in each wireless communication unit 7 of all routes in the wireless network system 1 in the base station 2.

  The communication quality evaluation unit 9 stores data related to communication quality collected in the base station 2 in the storage unit 6 and numerically evaluates the communication state of all routes of the wireless network system 1 for each wireless communication unit 7 and each frequency. It has a function.

  The route selection unit 10 determines, for each wireless communication unit 7, a communication route 4 on which each wireless terminal 3 can realize data communication most effectively based on the evaluation result of the communication quality evaluation unit 9. The frequency selection unit 14 determines, for each wireless communication unit 7, a frequency at which each wireless terminal 3 is least susceptible to radio wave interference based on the evaluation result of the communication quality evaluation unit 9.

  The communication control unit 11 generates communication control information according to the determination of the route selection unit 10 and the frequency selection unit 14 of the base station 2 and transmits the communication control information to the slave station via the wireless communication unit 7. At that time, the wireless communication unit 7 to be used is also selected. The communication control information includes information on the communication path of the slave station and communication synchronization, the frequency to be used, information on the wireless communication unit 7, and the like, which will be described in detail later.

  In the wireless network system 1 according to the present embodiment, the processing for selecting the communication path 4 of the base station 2 or the wireless terminal 3 and the frequency to be used can be executed in the same manner as in the first embodiment or the second embodiment, and thus description thereof is omitted. To do.

  Hereinafter, the flow of communication data in the present embodiment will be described in detail with reference to FIG. As an example, as shown in FIG. 17, the base station 2 is connected to the wireless terminal 3A and the wireless terminal 3B at different frequencies, the wireless terminal 3A is connected to the wireless terminal 3C and the wireless terminal 3D, and the wireless terminal 3B is connected to the wireless terminal 3C. In addition, it is assumed that the wireless terminal 3D is connected.

  The address of the base station 2 is set to 00, and the addresses of the wireless terminal 3A, the wireless terminal 3B, the wireless terminal 3C, and the wireless terminal 3D are set to 01, 02, 03, and 04, respectively.

  First, the base station 2 transmits communication control information at different frequencies simultaneously to the wireless terminal 3A and the wireless terminal 3B (processing 1701, processing 1702).

  This communication control information is composed of, for example, a frame 180 as shown in FIG.

  As in the case of the first and second embodiments, the communication control information may be individually transmitted to the wireless terminal 3 by unicast communication, or simultaneously transmitted to a plurality of wireless terminals 3 by broadcast communication. Also good.

  FIG. 18 shows an example of a frame 180 when unicast communication is performed. The header information, footer information, transmission destination address, transmission source address, synchronization information, and path information of the frame 130 are the same as those of the frame 50 in the first embodiment.

  FIG. 19 shows a broadcast frame 180. The basic structure is the same as in the case of unicast, but a broadcast address such as FF is set as the destination address, and the frequency, synchronization information, and path information are set as the data table 60 for each slave station address. .

  Here, an example in which unicast communication is performed will be described.

  One or more frequencies used by each wireless communication unit of the wireless terminal 3 that has received the communication control information are set as the master station frequency. The frequency used by the connected slave station is set as the frequency of the slave station in the path information.

  Therefore, there is no need to set whether the connection with the slave station in the route information is valid or invalid. That is, it may be valid if it is the same frequency as the master station, and invalid if it is a different frequency. The wireless terminal 3A that has received the frame 181 as the communication control information from the base station 2 by processing 1701 sets any one frequency of the wireless communication unit 7 to 1, and transmits data at a timing according to the synchronization information. . Further, any one of the remaining wireless communication units 7 is set to 2.

  Here, for example, the wireless terminal 3A executes data transmission addressed to the base station 2 (process 1703) and transmission of communication control information to the slave station (process 1705, process 1709) within the allocated time. The data transmission of processing 1703, processing 1705, and processing 1709 may be in different orders, may be executed collectively by broadcast transmission, or may be performed multiple times within the allocated time.

  In the processing 1702, the data addressed to the master station is added with the communication quality of the path measured by itself and the information of the communication quality measured by the slave station as in the first embodiment. Here, the wireless terminal 2 can simultaneously measure the communication quality not only at the frequency 1 but also at the frequency 2. However, information about the used frequency and the wireless communication unit 7 is also added to the communication quality information.

  In the communication control information shown in the frame 181, the wireless terminal 3A is set to 3 as the communication allocation time, and the wireless terminal 3C and the wireless terminal 3D are set as slave stations of the same frequency 1. Therefore, communication control information from the wireless terminal 3A to the slave station is set as shown in a frame 183 or a frame 184, for example.

  The data transmission from the wireless terminal 3A to the slave station in the processing 1705 and the processing 1709 may be performed by transmitting the communication control information and the general data together or may be divided and transmitted. Next, the wireless terminal 3C or the wireless terminal 3D that has received the communication control information from the wireless terminal 3A transmits data to the master station according to the set frequency, start time, and allocated time, similarly to the processing 1703 (processing 1708, Process 1711).

  On the other hand, for the wireless terminal 3B that has received the frame 182 as the communication control information from the base station 2 by the processing 1702, as in the case of the wireless terminal 3A, any one frequency of the wireless communication unit 7 is set to 2 and synchronized. Data is transmitted at the timing according to the information. Also, one of the remaining radio communication units 7 is set to 1.

  Thereafter, similarly, data transmission to the master station (process 1704), communication control information transmission to the slave station, and data transmission (process 1706, process 1709) are executed. An example of setting communication control information for the wireless terminal 3C and the wireless terminal 3D is shown in a frame 185 and a frame 186 in FIG. The slave station that has received the communication control information from the wireless terminal 3B performs data transmission to the master station in exactly the same manner (process 1708 and process 1712).

  In the above processing, the communication processing between the wireless terminal 3A and the slave station and the communication processing between the wireless terminal 3B and the slave station can be executed simultaneously because different frequencies 1 and 2 are used. The optimum communication path and the optimum frequency selection method can be performed in the same manner as in the first and second embodiments.

  As described above, according to this embodiment, high-speed data communication is possible by using different frequencies in the plurality of wireless communication units 7. Furthermore, since communication quality measurement data of different frequencies can be collected at the same time, communication can be performed by selecting an optimum path and frequency faster than in the first and second embodiments.

  The present invention can be widely used for communication equipment such as a base station and a wireless terminal constituting a wireless network system represented by a wireless LAN (Local Area Network), a wireless PAN (Personal Area Network), and the like.

1 is a diagram illustrating a configuration example of a wireless network system 1 according to the present invention. FIG. 3 is a diagram illustrating a configuration example of a wireless terminal base station 2 according to the first embodiment. 3 is a flowchart illustrating an example of communication quality measurement and route selection processing in the wireless network system 1 according to the first embodiment. FIG. 3 is a sequence diagram illustrating an example of a data flow in the wireless network system 1 according to the first embodiment. It is the figure which showed the example of the data frame 50 in the unicast communication of communication control information. It is the figure which showed the example of the data frame 50 in the broadcast communication of communication control information. It is the figure which showed the example of data of communication quality. It is the figure which showed the example of the measurement result of communication quality. 5 is a flowchart showing an example of processing for determining an optimum communication path 4; FIG. 6 is a diagram illustrating a configuration example of a wireless terminal base station 2 according to the second embodiment. 5 is a flowchart showing an example of communication quality measurement, path and frequency selection processing in the wireless network system 1; FIG. 10 is a sequence diagram illustrating an example of a data flow in the wireless network system 1 according to the second embodiment. It is the figure which showed the example of the data frame 130 in the unicast communication of communication control information. It is the figure which showed the example of the data frame 130 in the broadcast communication of communication control information. It is the figure which showed the example of data of communication quality. 6 is a diagram illustrating a configuration example of a wireless terminal base station 2 according to Embodiment 3. FIG. FIG. 10 is a sequence diagram illustrating an example of a data flow in the wireless network system 1 according to the third embodiment. It is the figure which showed the example of the data frame 180 in the unicast communication of communication control information. It is the figure which showed the example of the data frame 180 in the broadcast communication of communication control information.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless network system 2 Wireless terminal base station 3 Wireless terminal 4 Communication path 5 Processing part 6 Storage part 7 Wireless communication part 8 Communication quality totaling part 9 Communication quality evaluation part 10 Path selection part 11 Communication control part 12 Communication quality measurement part 13 Antenna 14 Frequency selection unit 15 Frequency switching unit,
50, 130, 180 frames

Claims (15)

A wireless network system composed of a plurality of wireless terminals connected to each other by wireless signals and performing multi-hop communication,
The wireless terminal is
Communication quality measuring means for measuring communication quality with other adjacent wireless terminals;
Communication quality totaling means for sharing the communication quality information with other wireless terminals;
Communication control means for controlling its own communication path and communication time according to the control information received from the other wireless terminal, and generating control information to be transmitted to the other wireless terminal;
At least one of the wireless terminals is a base station that manages communication of the wireless network system,
A communication quality evaluation unit that numerically evaluates the communication quality shared by the communication quality totaling unit and determines the superiority or inferiority of a communication path;
Path selection means for generating control information so as to select a communication path through which each of the wireless terminals constituting the wireless network system can communicate with good communication quality,
A wireless network system characterized in that wireless communication is performed using a communication path with good communication quality by repeatedly and periodically executing the measurement of the communication quality and the transmission of the control information. In wireless terminals that connect to each other by wireless signals and perform multi-hop communication,
Communication quality measuring means for measuring communication quality with other adjacent wireless terminals;
Communication quality totaling means for sharing the communication quality information with other wireless terminals;
Communication control means for controlling its own communication path and communication time according to the control information received from the other wireless terminal and generating control information to be transmitted to the other wireless terminal;
A wireless terminal characterized in that wireless communication is performed using a communication path with good communication quality by repeatedly performing the measurement of the communication quality and the transmission of the control information periodically and simultaneously. The wireless terminal according to claim 2,
The wireless terminal is
A communication quality evaluation means for numerically evaluating the communication quality shared in a wireless network system and determining superiority or inferiority of a communication path;
Path selection means for generating control information so as to select a communication path through which each of the wireless terminals constituting the wireless network system can communicate with the best communication quality,
A wireless terminal that manages communication of the entire wireless network system by repeatedly measuring the communication quality and transmitting the control information periodically and simultaneously. In a route selection method for selecting a communication route of a wireless terminal in multi-hop communication,
Calculate the communication quality between the wireless terminals adjacent to each other, and then calculate the communication quality when passing through the plurality of wireless terminals in multi-hop communication, and the communication quality is high and overlaps with other selected routes A route selection method characterized by selecting a route with few locations as a route with good communication quality. In a communication control method for controlling a communication method of a wireless terminal in multi-hop communication,
Information for synchronizing communication times of a plurality of wireless terminals and information for determining a communication path are transmitted as control information to other wireless terminals, and at the same time, communication quality of the communication path is measured by transmitting and receiving the control information. The communication control method characterized by performing. A wireless network system composed of a plurality of wireless terminals connected to each other by wireless signals and performing multi-hop communication,
The wireless terminal is
Communication quality measurement means for performing communication while switching frequencies, and measuring communication quality with other adjacent wireless terminals for each frequency,
Communication quality totaling means for sharing the communication quality information with other wireless terminals;
In accordance with control information received from the other wireless terminal, communication control means for controlling its own communication path, communication time and frequency, and generating control information to be transmitted to the other wireless terminal,
At least one of the wireless terminals is a base station that manages communication of the wireless network system,
Communication quality evaluation means for numerically evaluating the communication quality shared by the communication quality totaling means and determining the superiority or inferiority of the communication path for each frequency;
A path selection means for generating control information so as to select a communication path and a frequency with which the wireless terminals constituting the wireless network system can communicate with each other with good communication quality;
A wireless network system for performing wireless communication using a communication path and a frequency having good communication quality by periodically and simultaneously performing measurement of the communication quality and transmission of the control information. . In wireless terminals that connect to each other by wireless signals and perform multi-hop communication,
Communication quality measurement means for performing communication while switching frequencies, and measuring communication quality with other adjacent wireless terminals for each frequency,
Communication quality totaling means for sharing the communication quality information with other wireless terminals;
In accordance with control information received from the other wireless terminal, communication control means for controlling its own communication path, communication time and frequency, and generating control information to be transmitted to the other wireless terminal,
A wireless terminal that performs wireless communication using a communication path and frequency with good communication quality by periodically and simultaneously repeating measurement of the communication quality and transmission of the control information. In claim 7,
The wireless terminal is
Communication quality evaluation means for numerically evaluating the communication quality shared in a wireless network system and determining the superiority or inferiority of a communication path for each frequency;
Path selection means for generating control information so as to select a combination of a communication path and a frequency with which each of the wireless terminals composing the wireless network system can communicate with the best communication quality,
A wireless terminal that manages overall communication of the wireless network system. In a frequency selection method for selecting a frequency of a wireless terminal in multihop communication,
The communication quality between the wireless terminals adjacent to each other is calculated for each frequency, the communication quality is evaluated by adding a weight according to the time when the communication quality is measured and the degree of adjacency of the frequency, and the communication quality is increased. A frequency selection method characterized by selecting a frequency as described above. In a communication control method for controlling a communication method of a wireless terminal in multi-hop communication,
Information for synchronizing communication times of a plurality of the wireless terminals, information for determining a communication path, and information for determining a frequency are transmitted to other wireless terminals as control information, and at the same time, the control A communication control method, comprising: measuring communication quality of a communication path for each frequency by transmitting and receiving information. A wireless network system composed of a plurality of wireless terminals connected to each other by wireless signals and performing multi-hop communication,
The wireless terminal is
Means for communicating simultaneously with a plurality of said wireless terminals using a plurality of frequencies;
Communication quality measuring means for simultaneously measuring a plurality of communication qualities with other adjacent wireless terminals for each frequency;
Communication quality totaling means for sharing the communication quality information with other wireless terminals;
Communication control means for controlling a plurality of communication paths and communication times and frequencies of the communication terminal according to the control information received from the other wireless terminal, and generating control information to be transmitted to the other wireless terminal;
At least one of the wireless terminals is a base station that manages communication of the wireless network system,
A communication quality evaluation unit that numerically evaluates the communication quality shared by the communication quality totaling unit and determines the superiority or inferiority of the communication path for each frequency;
A path selection means for generating control information so as to select a communication path and a frequency at which each of the wireless terminals constituting the wireless network system can communicate with good communication quality;
Wireless communication using a plurality of communication paths and frequencies with good communication quality by periodically and simultaneously performing measurement of the communication quality and transmission of the control information. Network system. In wireless terminals that connect to each other by wireless signals and perform multi-hop communication,
Means for communicating simultaneously with a plurality of said wireless terminals using a plurality of frequencies;
Communication quality measuring means for simultaneously measuring a plurality of communication qualities with other adjacent wireless terminals for each frequency; and
Communication quality totaling means for sharing the communication quality information with other wireless terminals;
Communication control means for controlling a plurality of communication paths and communication times and frequencies of the communication terminal according to the control information received from the other wireless terminal, and generating control information to be transmitted to the other wireless terminal;
Wireless communication using a plurality of communication paths and frequencies having good communication quality by periodically and simultaneously performing measurement of the communication quality and transmission of the control information. Terminal. In claim 12,
The wireless terminal is
Communication quality evaluation means for numerically evaluating the communication quality shared by the communication quality totaling means and determining the superiority or inferiority of the communication path for each frequency;
A path selection means for generating control information so as to select a communication path and frequency at which each of the wireless terminals constituting the wireless network system can communicate with the best communication quality;
A wireless terminal that manages overall communication of the wireless network system. In claim 12,
The wireless terminal is a base station that manages the overall communication of the wireless network system,
A communication quality evaluation unit that numerically evaluates the communication quality shared by the communication quality totaling unit and determines the superiority or inferiority of the communication path for each frequency;
Route selection means for generating control information so as to select a communication route and a frequency at which the wireless terminals constituting the wireless network system can communicate with each other with good communication quality;
Wireless communication using a plurality of communication paths and frequencies having good communication quality by periodically and simultaneously performing measurement of the communication quality and transmission of the control information. Terminal. In claim 12,
The wireless terminal is
Means for communicating simultaneously with a plurality of said wireless terminals using a plurality of frequencies;
Communication quality measuring means for simultaneously measuring a plurality of communication qualities with other adjacent wireless terminals for each frequency; and
Communication quality totaling means for sharing the communication quality information with other wireless terminals;
Communication control means for controlling a plurality of communication paths and communication times and frequencies of the communication terminal according to the control information received from the other wireless terminal, and generating control information to be transmitted to the other wireless terminal;
Communication quality measuring means for measuring the communication quality with other wireless terminals in the vicinity for each frequency,
A wireless terminal that transmits information on the communication quality to another wireless terminal and sets its own communication path and frequency according to a control command from the other wireless terminal.

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