WO2013084520A1

WO2013084520A1 - Wireless communication system, and method for controlling communication pathways in wireless communication system

Info

Publication number: WO2013084520A1
Application number: PCT/JP2012/061742
Authority: WO
Inventors: 誠谷川原; 川口　貴正; 清野　憲二; 徳久柳原; 苗村　万紀子; 藤井　健二郎
Original assignee: 株式会社日立産機システム
Priority date: 2011-12-06
Filing date: 2012-05-08
Publication date: 2013-06-13
Also published as: JP5739794B2; JP2013121010A

Abstract

Provided is a wireless communication system in which communications from non-moving wireless devices are relayed through other wireless devices to a base station, wherein the base station retains position information for the individual wireless devices, and status information for communication among wireless devices. When a pathway from a first wireless device to the base station is sought, a pathway control means of the base station seeks for wireless devices within a cell of a given size including the first wireless device, and on the basis of communication status information, selects a second wireless device having the best communication quality with the first wireless device from among the wireless devices within the cell. A third wireless device evaluated as having quality communication quality within a given threshold value in comparison to that of the second wireless device, as well as being at greater height than the second wireless device, is selected from wireless devices within the search space, and the selected third wireless device is designated as the next wireless device for the first wireless device to communicate with on the pathway. Communication can thereby consistently take place over highly reliable communication pathways in the wireless communication system.

Description

Wireless communication system and communication path control method for wireless communication system

The present invention relates to a radio communication system and a communication path control method of the radio communication system, and more particularly, to an ad hoc network system having a relay function of a radio device, and stable to a base station when the radio device does not move. The present invention relates to a radio communication system suitable for securing a highly reliable communication path and a communication path control method for the radio communication system.

In recent years, a solar power generation system has been introduced in each home, and a smart grid system that wants to use electric power efficiently is being studied as small power generation facilities are dispersed.

In order to realize such a system, it is necessary to adjust the balance between the power generation side (supply side) and the consumption side (demand side) of power from commercial power sources from power companies and power generation facilities owned by companies and individuals. There is. Thus, information on the consumer side (demand side) is fed back, and power is supplied from the nearby power generation side (supply side) to construct a network. For example, a power meter installed in each home is provided with a communication function, and power consumption information is periodically fed back.

However, enormous costs are required to newly wire such a network, and the running cost of communication becomes enormous if a cellular phone communication network is used even when wirelessly realized.

Therefore, building an original network wirelessly is being studied. In particular, the construction of a unique network using a low-power radio in the 900 MHz band such as 915 MHz has been studied. This network becomes an ad hoc network system in which each wireless device relays and transmits information of a power meter (wireless device) having a communication device function to each home to a base station.

For example, Patent Document 1 discloses a conventional technique for an ad hoc network system using wireless communication. In this patent document 1, in an ad hoc network that relays (multi-hops) a wireless device that directly receives electromagnetic waves between wireless devices, the wireless power is not easily turned off in order to minimize the frequency of changing the communication route. There has been disclosed a wireless communication system in which a communication route including a device and a wireless device that is difficult to move is selected as much as possible (see summary, etc.).

Also, in Patent Document 2, each member terminal is equipped with a GPS for positioning, and when communication with an adjacent group is interrupted, a leader terminal belonging to that group corrects the communication route to the adjacent group. An ad hoc network system is disclosed.

JP 2006-020221 A JP 2009-159113 A

In Patent Document 1 and Patent Document 2 of the above prior art, the absolute position is acquired using GPS positioning means, and the routing is determined from the positional relationship with the terminal, the repeater, and the base station, and the value of the radio wave intensity. This search for a communication path generally requires complicated processing and takes time. Immediately after the relay device leaves or enters the network, data packets in the middle of communication are buffered by the relay device until a new transmission destination is found. If the buffer of the relay device overflows, packet loss may occur.

In addition, when searching for a new communication route, it is necessary to transmit a large amount of data packets, so that packet loss due to increased traffic is more likely to occur. Further, packet resending processing frequently occurs at the application level due to packet loss, and there is a possibility that a vicious circle of wasteful data packets increases. Therefore, in such a network, it is important to select in advance a route that does not require route re-search as much as possible.

On the other hand, it is known that in radio communication, generally, the higher the antenna is above the ground surface, the longer the radio wave propagation distance. For example, an antenna at a height of 5 m above the ground has a longer radio wave propagation distance than an antenna at a height of 1 m above the ground. This is due to the influence of reflected waves from the ground.

The present invention has been made to solve the above-described problems, and its object is to provide a stable wireless communication system in which wireless communication is performed from each wireless device that does not move to another base station to the base station. An object of the present invention is to provide a wireless communication system capable of performing communication through a highly reliable communication path.

The wireless communication system according to the present invention relates to a wireless communication system that includes a plurality of wireless devices that do not move and a base station, and each wireless device relays another wireless device and communicates along a route to the base station. Each wireless device includes GPS or other location information acquisition means for acquiring its own location information, and communication status information acquisition means for acquiring information related to communication quality with other wireless devices. Means for receiving position information acquired by each wireless device; a position information table for holding the received position information; and means for receiving information regarding communication quality with other wireless devices acquired by each wireless device; A communication state information totaling table that holds information relating to communication quality with other received wireless devices, and route control means for obtaining a route between the wireless devices.

Then, when the route control means obtains a route from the first wireless device to the base station, the wireless device in the cell which is a three-dimensional search space having a certain size including the first wireless device. A device is obtained, and a second wireless device having the best communication quality with the first wireless device is selected from the wireless devices in the cell based on the communication state information aggregation table.

Then, based on the communication state information aggregation table, the communication quality evaluation with the second wireless device is compared among the wireless devices in the search space, and is within a certain threshold, and the position information A wireless device that selects a third wireless device having a height higher than that of the second wireless device based on the table and communicates the selected third wireless device next to the first wireless device in the path; To do.

In addition, the configuration of another radio system is related to a radio communication system in which a plurality of radio devices that do not move and a base station are included, and each radio device relays another radio device and communicates along a route to the base station. Each radio apparatus acquires position information acquisition means such as GPS for acquiring its own position information, position information transmission / reception means for receiving position information of other radio apparatuses and transmitting its own position information, and acquisition. A position information table that holds the position information of the received wireless device and the received position information of the other wireless device, a communication state information acquisition unit that acquires information about communication quality with the other wireless device, and the received other wireless device A communication state information table that holds information relating to communication quality with the wireless communication device, and a route control unit that obtains a wireless device that performs next relay on the route of the base station from the wireless device. That.

Then, the path control means obtains a wireless device in a cell, which is a three-dimensional search space having a certain size including the wireless device, when obtaining a wireless device to perform the next relay from the wireless device, and performs communication. Based on the state information table, the wireless device having the best communication quality with the wireless device is selected from the wireless devices in the search space, and the wireless device in the search space is selected based on the communication state information table. The communication quality with the wireless device having the best communication quality with the wireless device among the devices is compared, and the communication quality with the wireless device is within a certain threshold and based on the location information table. A wireless device that selects a wireless device having a height higher than the best wireless device as a wireless device that relays from the wireless device, and that communicates the wireless device selected as the relaying wireless device next to the wireless device in the path To.

As described above, in the present invention, radio waves are routed by giving priority to the height direction by using the property that the antenna flies farther as the antenna is higher than the ground. The present invention collects power consumption information by a smart meter. In addition, in multi-hop (multi-stage relay) and ad hoc wireless communication for power generation control such as solar power generation, each wireless device is used in wireless communication that enables mutual communication via a relay device. The frequency of route re-searching is low, and the communication network is sufficiently stable and reliable.

Advantageous Effects of Invention According to the present invention, in a wireless communication system that performs wireless communication from a wireless device that does not move to another base station to a base station, wireless communication that can be stably performed using a highly reliable communication path. A communication system can be provided.

It is a figure which shows the structure of the radio | wireless communications system which concerns on 1st embodiment of this invention. It is a figure which shows the structure of the radio | wireless apparatus which concerns on 1st embodiment of this invention. It is a figure which shows the structure of the base station which concerns on 1st embodiment of this invention. 6 is a diagram illustrating an example of a position information table 270 stored in a storage unit 202a of the wireless device 101. FIG. FIG. 3 is a diagram illustrating an example of messages exchanged between a wireless device 101 and a base station 102. 6 is a diagram illustrating an example of a communication state information table 281 stored in a storage unit 202a of the wireless device 101. FIG. It is a figure which shows the example of the positional information table 280 stored in the memory | storage part 202b of the base station 102. FIG. It is a figure which shows the example of the communication status information total table 281 stored in the memory | storage part 202b of the base station 102. FIG. It is a figure which shows the example of the path | route control table 282 stored in the memory | storage part 202b of the base station 102. FIG. It is a conceptual diagram for demonstrating the process which calculates | requires the path | route from a radio | wireless apparatus to a base station. It is the figure which showed the example of the cell used as the search space of the radio | wireless apparatus used as the next path | route from a certain radio | wireless apparatus (the 1). It is the figure which showed the example of the cell used as the search space of the radio | wireless apparatus used as the next path | route from a certain radio | wireless apparatus (the 2). It is a flowchart which shows the process which calculates | requires the path | route from a radio | wireless apparatus to a base station. It is a figure which shows the structure of the radio | wireless apparatus which concerns on 2nd embodiment of this invention. It is a figure which shows the structure of the base station which concerns on 2nd embodiment of this invention. 6 is a diagram illustrating an example of a position information table 275 stored in a storage unit 202c of a wireless device 101. FIG. 7 is a flowchart illustrating processing for obtaining a wireless device around a certain wireless device for relay in a wireless communication system according to a second embodiment of the present invention.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.

Embodiment 1
The wireless communication system according to the first embodiment of the present invention will be described below with reference to FIGS.
First, the configuration of the wireless communication system according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a diagram showing a configuration of a wireless communication system according to the first embodiment of the present invention.
FIG. 2 is a diagram illustrating the configuration of the wireless device according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating the configuration of the base station according to the first embodiment of the present invention.

In this embodiment, an example will be described in which the base station acquires position information of each wireless device, determines a communication route, and transmits the communication route information to each wireless device.

The wireless communication system 100 according to the first embodiment of the present invention includes

wireless devices

101, 111, 121, a base station 102, and a network 103 as shown in FIG.

The base station 102 is installed in the utility pole 104, the wireless device 101 is installed in the detached house 105, the wireless device 111 is installed in the detached house 115, and the wireless device 121 is installed in the apartment house 106.

The wireless device 101 is a device that wirelessly communicates with the base station 102 and transmits sensor measurement information via

other wireless devices

111 and 121 when radio waves do not reach the base station 102 directly. For example, it is a power meter that measures the power of each household and sometimes transmits meter-reading information that is the basis for calculating the electricity bill.

Here, the sensor information to be measured is an electric power meter, but gas or water may be measured, or power generation amount of the solar power generation system may be measured.

The base station 102 is connected to a plurality of

wireless devices

101, 111, and 121 by wireless communication, collects sensor information measured by the wireless device 101, and collects data from a plurality of base stations (not shown). Send data to the data center.

The network 103 is connected to a plurality of base stations and connected to a data center (not shown).

The utility pole 104 is a wooden or reinforced concrete pole on which the base station 102 is installed. For example, the base station 102 is installed on the utility pole 104 at a height of several meters from the ground surface.

The house 105 is, for example, a detached house, and the wireless device 101 is installed.
Similarly, in the detached house 115, the wireless device 111 is installed.

The apartment house 106 is, for example, a high-rise apartment, and each floor lives in a private room where a plurality of families are sold. A wireless device 101 is installed in each home.

As shown in FIG. 2, the wireless device 101 (same for other wireless devices) includes a CPU 201, a storage unit 202 a, a clock unit 203, a position information acquisition unit 204, a power measurement unit 205, an antenna 206, and a wireless unit 220. Consists of

The CPU 201 is an arithmetic processing device that controls the operation of each unit of the wireless device and executes and processes a program stored in the storage unit 202a. Although not shown, it contains a nonvolatile semiconductor memory whose contents can be changed but the contents disappear when the power is turned off. The semiconductor memory temporarily calls programs and holds variables and table information.

The CPU 201 is connected to the storage unit 202a through a memory bus, and is connected to the clock unit 203 through a signal line. The position information acquisition unit 204 is not necessarily included in the wireless apparatus 101, but is connected via a serial communication interface or the like when included. When not included, for example, short-distance wireless communication, for example, a Bluetooth interface is used. The power measuring unit 205 is connected by, for example, CT. The wireless unit 220 is connected by a serial communication interface such as a clock synchronization method such as SPI.

The storage unit 202a is a non-volatile semiconductor memory or a hard disk drive (HDD) that stores processing programs for a long period of time. The storage unit 202a includes, for example, a reception processing program 211, a transmission processing program 212, a position information table 270, a communication state information table 271, a position information communication program 213, a communication state management program 214, a relay processing program 215, and a power information processing program. 216 is held.

Furthermore, the reception processing program 211 has an LQI calculation unit 216 and a decoding unit 217.

The transmission processing program 212 includes a carrier sense unit 218 and an encoding unit 219.

The clock unit 203 is a device that includes a crystal resonator or a crystal oscillator, and provides a clock signal that serves as a guideline for the operation of the CPU 201. For example, the CPU 201 gives a pulse signal at 24 MHz.

The position information acquisition unit 204 is a part that acquires a position on the earth where the wireless device 101 is installed. For example, it is a system that can acquire the position by a global navigation satellite system of a global satellite positioning system, etc., and measures the latitude / longitude / altitude on the earth and stores the latitude / longitude / altitude information in the storage unit 202a. . It is not necessarily required to be latitude / longitude / altitude, and any device that acquires an absolute position on the earth or a relative position between the base station and another wireless device may be used. The position information acquisition unit 204 may have a resolution with an error of several meters in practice.

Further, as described above, the position information acquisition unit 204 does not necessarily have to be built in, and may be an external device. The position information acquisition unit 204 may use an atmospheric pressure sensor or the like particularly at an altitude. The atmospheric pressure may change depending on the weather, but if the weather is constant, the atmospheric pressure will drop if the altitude rises, and if it is a barometric sensor using 16-bit AD conversion, the floor number such as the first floor, the second floor, etc. is identified. can do.

Further, for example, positioning may be performed from a wireless device 101, a base station 102, or the like, which is a known position reference, using a wireless positioning technology such as TDOA or AOA, and converted into latitude and longitude height. For example, positioning is performed by optics, laser, ultrasonic waves, etc., and converted into latitude and longitude heights.

The power measuring unit 205 is a part called a clamp, for example, which measures a current flowing through a power line or measures a voltage by another means (not shown) to measure power. The measured data is given to the CPU 201 as digital data by A / D conversion, for example.

The antenna 206 is connected to the wireless unit 220 with, for example, a coaxial cable with an impedance of 50 ohms, and is a device for performing transmission and reception by wireless communication with the

other wireless devices

111 and 121. The wireless communication is performed by electromagnetic waves such as radio waves and infrared rays. Here, for example, a UHF band 920 MHz wireless is used. In FIG. 2, two antennas 206 are displayed, but one antenna or a plurality of antennas such as four may be used.

However, when there are a plurality of antennas 206, the types and installation positions of the antennas are different. For example, if one antenna is a built-in antenna, the other antenna is an external antenna. For example, if both external antennas are installed horizontally, the other is installed vertically. Further, when a laminated chip antenna is used as the built-in antenna, if a certain laminated chip antenna is installed horizontally on the substrate, another laminated chip antenna is installed vertically.

The reference signal generation unit 210 includes, for example, a crystal resonator or a crystal oscillator that generates a reference signal for the wireless unit 220 to transmit / receive a wireless signal, and generates a reference signal such as 32 kHz or 10 MHz, for example. .

The wireless unit 220 includes a transceiver switch 221, a receiver 222, a transmitter 223, an antenna switch 224, an impedance matching circuit 225, and a filter 226. As described above, the CPU 201 is connected by, for example, an SPI or clock synchronous serial communication interface. Further, the reference signal generator 210 is connected by a signal line.

The transceiver switch 221 is connected to the reception unit 222 and the transmission unit 223. For example, the transmission processing unit 226 is normally connected to the reception processing unit 225 through a signal line and disconnected from the transmission processing unit 226. When transmitting, although not shown, the switch is switched according to an instruction from the transmission processing unit 226 and the transmission processing unit 223 and the antenna 206 are connected.

The filter 222 is, for example, a SAW or a band-pass filter, and is a part that prevents unnecessary radiation.

The impedance matching circuit 223 is configured by, for example, a resistor, a capacitor, an inductance, and the like, and is a part that adjusts the impedance of the connection between the wireless unit 220 and the antenna 206 to, for example, 50 ohms.

The antenna switch 224 is a part for switching which antenna to output when there are a plurality of antennas 206. Switching is manual or is changed by a command from the CPU 201.

The receiving unit 225 is a part that receives a radio signal received from the antenna 206 and passes the data to the CPU 201. The reception unit 225 includes a demodulation processing unit 224 and an RSSI measurement unit 225.

The demodulation processing unit 231 is a part that demodulates data from, for example, radio waves of a radio signal received from the antenna 206, generates a reference wave for comparison with a carrier wave from the reference signal generation unit 210, and specifies a modulation scheme designated in advance. Compared with, this is the part where data is extracted.

An RSSI (Received Signal Strength Indicator) measurement unit 232 measures received power when received, converts the radio wave intensity (RSSI) to a value such as dBm, C / N0, and the like, and passes it to the CPU 201. .

The transmission unit 226 is a part that transmits data to the antenna 206 by the CPU 201.
The transmission unit 226 includes a carrier wave generation unit 233 and a modulation processing unit 234.

The carrier wave generation unit 233 is a part that generates a carrier wave from the reference signal generation unit 210, and includes, for example, a PLL frequency synthesizer, and generates, for example, 920 MHz as the carrier wave.

The modulation processing unit 234 performs modulation processing for data to be put on a 920 MHz radio wave. For example, this is a portion that performs modulation processing by PSK (Phase Shift Keying) or FSK (Frequency-Shift Keying).

Next, the reception processing program 211, the transmission processing program 212, the location information communication program 213, the communication state management program 214, the relay processing program 215, and the power information processing program 216 held in the storage unit 202a will be described.

The reception processing program 211 is a program that operates on the CPU 201. The reception processing program 211 acquires the reception data of the reception unit 225 from the wireless unit 220 via a serial communication interface such as SPI, and decodes the received data into a bit string. This is a program for confirming whether the message is addressed to an address and acquiring a payload portion to be described later.

The LQI (Link Quality Indicator) calculation unit 216 is a part that calculates the quality (Quality) of the received radio signal in the process of decoding it into a bit string or performing a parity calculation described later.

The decoding unit 217 acquires the reception data of the reception unit 225 and decodes it into a bit string.

The transmission processing program 218 is a program that determines whether or not it may be transmitted by itself and encodes a previously generated message and passes the data to the transmission unit 225 of the wireless unit 220 if transmission is acceptable. .

The carrier sense unit 218 measures the reception power at the antenna 206 from, for example, the RSSI measurement unit 232 of the reception unit 225. If the reception power is weak, the

other wireless devices

111 and 121, the base station 102, and the like are transmitting It is a part to confirm that it is not.

The encoding unit 219 is a part that encodes a message generated in advance and passes the data to the transmission unit 225 of the wireless unit 220.

The location information communication program 213 is a program for storing the location information of the base station 102 sent from the base station 102 in the location information table 270.

The communication state management program 214 is a program that collects communication states of wireless devices that can communicate around the wireless device 101 and stores them in the communication state information table.

The relay processing program 215 is a program that operates on the CPU 201, and the

wireless devices

101, 111, 121, etc. obtain other destination wireless devices in accordance with the route instructions from the base station 102 and instruct the transmission processing program. It is a program to do.

The power information processing program 216 is a program that operates on the CPU 201, is a program that acquires power information from the power measurement unit 205 via AD conversion and transmits the power information to the base station.

As shown in FIG. 3, the base station 102 includes a CPU 201, a storage unit 202 b, a clock unit 203, a location information acquisition unit 204, an antenna 206, and a radio unit 220.

The base station 102 functions as a gateway for the

wireless devices

101, 111, and 121 to collect power information from each wireless device and report it to the data center via the network 103. Further, the route information of each wireless device is obtained and route information is transmitted.

The base station 102 has the same configuration as that of the

wireless devices

101, 111, and 121 for the clock unit 203, the position information acquisition unit 204, the antenna 206, and the wireless unit 220, but does not include the power measuring unit 205. The contents of the program and data stored in the storage unit 202 are different.

The storage unit 202b of the base station 102 includes a position information table 280, a communication state information aggregation table 281, a route control table 282, a reception processing program 211, a transmission processing program 212, a position information communication program 290, a route control processing program 291, A power information aggregation program 295 is stored.

The location information communication program 213 is a program for storing location information sent from each wireless device in the location information table 280.

The route control processing program 291 is a program that calculates the route of each wireless device and transmits route information to each wireless device. The processing of this route control processing program 291 will be described in detail later.

The power information aggregation program 295 is a program that aggregates the power information measured by the power measurement unit 205 of each wireless device and processed by the power information processing program 216 and transmits it to the data center via the network 103.

Next, the data structure of the wireless communication system according to the first embodiment of the present invention will be described with reference to FIGS.
FIG. 4 is a diagram illustrating an example of the position information table 270 stored in the storage unit 202a of the wireless device 101.
FIG. 5 is a diagram illustrating an example of messages exchanged between the wireless device 101 and the base station 102.
FIG. 6 is a diagram illustrating an example of the communication state information table 281 stored in the storage unit 202a of the wireless device 101.
FIG. 7 is a diagram illustrating an example of the position information table 280 stored in the storage unit 202 of the base station 102.
FIG. 8 is a diagram illustrating an example of the communication state information aggregation table 281 stored in the storage unit 202 b of the base station 102.
FIG. 9 is a diagram illustrating an example of the path control table 282 stored in the storage unit 202 b of the base station 102.

The location information table 250 stored in the storage unit 202 of the wireless device 101 holds the location information of its own wireless device 101 and the location information of the base station 102 as shown in FIG.

The location information of the base station 102 is information transmitted from the base station 102. The position information of its own wireless device 101 is information acquired by the position information acquisition unit 204.

In FIG. 4, (x ₁ , y ₁ , z ₁ ) is illustrated, but for example, (latitude, longitude, altitude) is not necessarily latitude / longitude / altitude, but absolute on the earth The position or the relative position between the base station and another wireless device only needs to have a resolution with an error of several meters. For example, (latitude, longitude, sea level), (latitude, longitude, altitude), (latitude, longitude, sea level, floor floor), (latitude, longitude, altitude, floor floor) (latitude, longitude, barometric pressure), etc. May be.

For example, (latitude, longitude, altitude) is (north latitude 35.6888710, east longitude 140.7242, altitude 100 m).

(Latitude, Longitude, Sea level) may be (Latitude 35.698710 North, 140.7242 East, 100 m above sea level), or (Latitude 35.68710 North, 140.7242 East, 100 m above sea level, 3 floors) Information may be added.

The value above sea level is generated, for example, by comparing latitude and longitude information with map data (with sea level and altitude data) of Japan maintained by the Geographical Survey Institute. The collation method is acquired using the network 103 or the like.

Furthermore, it may be (latitude, longitude, barometric pressure value).

Alternatively, (x ₁ , y ₁ , z ₁ ) may be, for example, a 128-bit “location information code” proposed by the Geographical Survey Institute.

Next, message data of radio signals transmitted and received between the radio apparatus 101 and the base station 102 will be described.

The message 400 is a bit string data transmitted and received between wireless devices and between a wireless device and a base station as a wireless signal shown in FIG. 5A, a preamble 401, a destination address 402, a source address 403, a payload. (1) It is composed of 404 and parity 405.

The preamble 401 is a bit string such as “10111” such as an M-sequence GOLD code, and is a bit string for finding a radio signal from noise data.

The destination address 402 and the source address 403 are unique addresses held by the

wireless devices

101, 111, 121, the base station 102, and the like. For example, international addresses such as a 48-bit MAC address and a 64-bit such as EUI-64 are used. It is a globally and uniquely managed address.

The payload 404 is an area for storing data. For example, as shown in FIG. 5B, a message type 411 and message data 412 are stored.

Parity 405 is an area in which a bit string such as a destination address 402, a source address 404, and a payload 404 is calculated by a calculation formula such as CRC16 and a value is stored. Further, it is used for calculation by the LQI calculation unit 216 and the like.

The position information table 280 stored in the storage unit 202a of the wireless device 101 holds the position information of the base station 102 and all the position information of the wireless device 101 in the wireless management area, as shown in FIG. . Here, the device ID of each wireless device is 001-and the device ID of the base station is 000 (hereinafter referred to as "base station 000, wireless device 001, wireless device 002, ...").

As shown in FIG. 6, the communication state information table 271 stored in the storage unit 202a of the wireless device 101 holds each wireless device and communication quality information around it, and in this example, the communication quality is It is evaluated by RSSI. If the wireless device 000 is measuring, the RSSI value with the wireless device 002 is -73.0 [dBm].

The position information table 280 stored in the storage unit 202b of the base station 102 stores the position information of the base station 102 and the position information of all the wireless devices in the communication management area, as shown in FIG. The location information of the base station 102 is information acquired by its own location information acquisition unit 204. The position information of the wireless device is information acquired by the position information acquisition unit 204 from the position information of the wireless device of each device ID and transmitted from the wireless device to the base station.

The communication state information aggregation table 281 stored in the storage unit 202b of the base station 102 is a table that holds communication quality information with surrounding wireless devices sent from each wireless device, as shown in FIG. The RSSI is recorded for the pair of the wireless device ID of the measurement source and the wireless device ID that is the measurement target.

As shown in FIG. 9, the route control table 282 stored in the storage unit 202b of the base station 102 is a table representing a route from the wireless device having each device ID to the base station. The address of each wireless device is stored. Here, ad (00i) represents the address of the wireless device 00i with the device ID = 00i. For example, the second entry indicates that the route from the wireless device 002 with the device ID = 002 to the base station 000 is the base station 000. ← Wireless device 001 ← Indicates that the route is wireless device 002. The information in the route information table 270 is transmitted to the wireless device having each device ID. For example, the second entry is transmitted to the wireless device 002 having the device ID = 002.

Next, processing for calculating a route from the wireless device to the base station in the wireless communication system according to the first embodiment of the present invention will be described with reference to FIGS.
FIG. 10 is a conceptual diagram for explaining processing for obtaining a route from a wireless device to a base station.
FIG. 11A and FIG. 11B are diagrams illustrating an example of a cell serving as a search space for a wireless device that is the next route from a certain wireless device.
FIG. 12 is a flowchart illustrating processing for obtaining a route from the wireless device to the base station.

In the processing in this embodiment, as shown in FIG. 10, a wireless device that is a route of a base station is sequentially obtained from wireless devices in a radio wave management area of a certain base station.

This processing is performed by the CPU 201 executing the route control processing program 291 of the base station 102.

First, the base station collects location information from each wireless device and stores it in the location information table 270 shown in FIG. 6 (S01).

Next, the base station collects the communication quality information of the adjacent wireless device from each wireless device, reports it to the base station, and stores it in the communication quality information totaling table 281 shown in FIG. 8 (S02). ).

When transmitting the communication quality information of the adjacent wireless device from each wireless device, it is only necessary to exclude a wireless device with too poor communication quality from candidates in advance. For example, in FIG. 6, the wireless device 008 and the wireless device 009 whose communication quality is lower than −85 [dBm] are prevented from sending information to the base station.

Next, i ← 0 is set (S03).

Next, rs (i) ← the wireless device at the start point is set (S03). Here, rs (i) represents the i-th wireless device.

Next, it is determined whether rs (i) is a base station (S05).

If rs (i) is a base station, the search is complete, rs (0) = starting radio apparatus, rs (1),..., rs (i−1), rs (i) = base station Are stored in the routing control table shown in FIG. 9 (S12), and the process is terminated.

If rs (i) is not a base station, cell (i) is set (S06). Here, cell (i) represents the i-th cell. The cell is a search space for finding an optimal wireless device as a route from rs (i) to rs (i + 1) (FIG. 10). As a model of the cell, as shown in FIG. 11A, a straight line is drawn from rs (i) to the base station, and from there to −π / 4 to π / 4 [rad] (that is, 90 degrees) In the meantime, a shape (a shape when the watermelon is cut) obtained by cutting out a sphere centered at rs (i) (a point within a certain distance from rs (i) in a three-dimensional space) is used. Further, as shown in FIG. 11B, a shape in which a straight line is drawn from rs (i) to the base station, and a pillar body is cut out from −π / 4 to π / 4 on the waterside surface therefrom. In this way, the cell shape is determined by searching for a wireless device heading in the direction of the base station and excluding a wireless device that is too far from rs (i) from wireless device candidates for the next route in advance. There is a meaning to do. Here, in any type of cell, the angle taken from the direction of the base station may be widened or narrowed. In general, the more the number of wireless devices that are candidates in the search space, the narrower the angle to be cut, and the more the number of wireless devices that are candidates, the wider the angle to be cut.

Next, it is determined whether or not there is a wireless device in cell (i) (S07).

If there is no wireless device in cell (i), an error is made (S13), and the cell size which is the search space is reset, and the process for obtaining the route is re-executed.

When there is a wireless device in cell (i), the one with the highest communication quality (that is, the one with the large RSSI) is set as rs _Q (S08).

_{Then, RSSI (rs Q) -RSSI (} rs) <ε, a, and selects a wireless device rs in height (rs) is the largest cell (i) (S09). Here, RSSI (rs) is the RSSI value of the wireless device rs, and ε is a predetermined threshold value. Further, height (rs) is the height of the wireless device rs evaluated from the position information.

Next, i ← i + 1 is set (S10).

Next, rs (i) ← the selected rs is set (S11), the process returns to S05, and the process is repeated.

In this embodiment, the communication quality between the wireless devices is evaluated by the RSSI value, but may be evaluated by another index, for example, the LQI value.

As described above, in the wireless communication system according to the present embodiment, when selecting a route between wireless devices, a radio wave is simply determined in consideration of the height, not the adjacent radio wave intensity, to determine the device to be relayed to the base station. Therefore, stable and reliable communication quality can be obtained.

[Embodiment 2]
Hereinafter, the radio | wireless communications system which concerns on 2nd embodiment of this invention is demonstrated using FIG. 13 thru | or FIG.
First, the configuration of a wireless communication system according to the second embodiment of the present invention will be described with reference to FIGS.
FIG. 13 is a diagram illustrating a configuration of a wireless device according to the second embodiment of the present invention.
FIG. 14 is a diagram illustrating a configuration of a base station according to the second embodiment of the present invention.
FIG. 15 is a diagram illustrating an example of the position information table 275 stored in the storage unit 202 c of the wireless device 101.

In the first embodiment, the example in which the base station acquires the position information of each wireless device and determines the communication path has been described. In the present embodiment, each wireless device collects position information from surrounding wireless devices and determines a wireless device to be a next route.

Since the hardware configurations of the wireless device 101 and the base station 102 are the same as those in the first embodiment, different points will be mainly described.

As shown in FIG. 13, the storage unit 202 c of the wireless device 101 has a reception processing program 211, a transmission processing program 212, a position information table 275, a communication state information table 271, a position information communication program 285, and a path control processing program 286. The relay processing program 215 and the power information processing program 216 are held.

Among these, the reception processing program 211, the transmission processing program 212, the communication state information table 271, the relay processing program 215, and the power information processing program 216 are the same as those in the first embodiment.

The position information communication program 285 differs from the position information communication program of the first embodiment in that in addition to setting the position information of the base station in the position information table 275, the position information communication program 285 is transmitted from wireless devices around its own wireless device. This is a program for storing the received position information in the position information table 275.

The route control processing program 286 is a program for selecting a wireless device to be a next route among wireless devices around the wireless device.

The location information table 275 is different from the location information table 270 of the first embodiment. As shown in FIG. 15, in addition to the location information of the base station and its own location information, the location information table 275 is the wireless It also holds device position information.

In this embodiment, it is assumed that a protocol for exchanging position information with other wireless devices is provided, and the path control processing program 286 stores the received position information of the wireless device in the position information table 275.

The storage unit 202d of the base station 102 holds a position information communication program 290 and a power information totaling program 295 as shown in FIG.

The location information communication program 290 and the power information aggregation program 295 are the same as those described in the first embodiment. In this embodiment, since the route is determined on the wireless device side, no route processing program is required on the base station side.

Next, with reference to FIG. 16, a description will be given of processing for obtaining a surrounding wireless device for relaying from a certain wireless device in the wireless communication system according to the second embodiment of the present invention.
FIG. 16 is a flowchart showing processing for obtaining a surrounding wireless device for relaying from a certain wireless device in the wireless communication system according to the second embodiment of the present invention.

This processing is performed by the CPU 201 executing the route control processing program 286 of the wireless device 101.

First, the base station collects position information from surrounding wireless devices and stores it in the position information table 275 shown in FIG. 15 (S20).

Next, the communication quality information of the surrounding wireless devices is collected and set in the communication quality information table 271 shown in FIG. 7 (S21).

Next, the cell is set around itself (S22). The idea about the cell is the same as in the first embodiment.

Next, it is determined whether there is a wireless device in the cell (S23).

If there is no wireless device in the cell, as an error (S27), the cell is re-established to expand the size of the search space, and the process for obtaining the route is re-executed.

When there is a wireless device in the cell, the one with the highest communication quality (that is, the one with the highest RSSI) is set as rs _Q (S24).

Then, the radio device rs in the cell that has RSSI (rs _Q ) −RSSI (rs) <ε and the largest height (rs) is selected (S25). The meaning of the symbols is the same as in the first embodiment.

Then, rs is determined as the transmission destination (relaying wireless device) (S26), and the process is terminated.

This embodiment has a feature that the processing load of the base station is reduced because the route selection is performed by each wireless device as compared with the first embodiment.

101 ... Wireless device 102 ... Base station 103 ... Network 104 ... Telephone pole 105 ... Housing 106 ... Apartment house 201 ... CPU
202a, 202b, 202c, 202d ... saving unit 203 ... clock unit 204 ... position information acquisition unit 205 ... power measurement unit 206 ... antenna 207 ... antenna switch 208 ... impedance matching circuit 209 ... filter 210 ... reference signal generation unit 220 ... wireless Unit 221 ... transceiver switch 222 ... reception unit 223 ... transmission unit 224 ... antenna switch 225 ... impedance matching circuit 226 ... filter

Claims

In a wireless communication system comprising one or more wireless devices and a base station, wherein each wireless device relays another wireless device and performs communication according to a route to the base station,
Each of the wireless devices is
Position information acquisition means for acquiring own position information;
Communication state information acquisition means for acquiring information related to communication quality with other wireless devices,
The base station
Means for receiving location information acquired by each of the wireless devices;
Means for holding the received position information;
Means for receiving information related to communication quality with other wireless devices acquired by each of the wireless devices;
Means for holding information on communication quality with the other received wireless device;
Route control means for obtaining a route between the wireless devices,
The route control means includes
When obtaining a route from the first wireless device to the base station,
Seeking a wireless device in a three-dimensional search space having a certain size including the first wireless device;
Based on the information regarding the communication quality with other wireless devices acquired by each wireless device, the communication quality in communication with the first wireless device is the best among the wireless devices in the search space. Choose a good second wireless device and
Based on the information regarding the communication quality with other wireless devices acquired by each of the wireless devices, the evaluation of the communication quality with the second wireless device is compared among the wireless devices in the search space. Selecting a third wireless device within a certain threshold and having a height higher than that of the second wireless device based on the received position information,
The wireless communication system, wherein the selected third wireless device is a wireless device that communicates next to the first wireless device in the path.
In a communication path control method of a wireless communication system, comprising one or more wireless devices and a base station, each wireless device communicating with another wireless device according to a route to the base station,
Each of the wireless devices is
Position information acquisition means for acquiring own position information;
Communication state information acquisition means for acquiring information related to communication quality with other wireless devices,
The base station
Means for receiving location information acquired by each of the wireless devices;
A position information table for holding the received position information;
A communication status information aggregation table that holds information related to communication quality with other wireless devices acquired by each wireless device;
Communication means for holding information relating to communication quality with the other received wireless device;
Route control means for obtaining a route between the wireless devices,
Each of the wireless devices acquires the position information of itself by the position information acquisition means;
Each of the wireless devices transmits the acquired location information of the device, and the base station receives the location information;
The base station holding the received location information in the location information table;
Each of the wireless devices acquires information on communication quality with other wireless devices by the communication state information acquisition means;
Each of the wireless devices transmits the acquired information on the communication quality with the other wireless device, and the base station receives the information on the communication quality with the other wireless device;
The base station holds the received information regarding the communication quality with the other wireless device in the communication state information aggregation table;
When the route control means obtains a route from the first wireless device to the base station, it obtains a wireless device in a three-dimensional search space having a certain size including the first wireless device. Steps,
A second wireless device having the best communication quality in communication with the first wireless device from among the wireless devices in the search space based on the communication state information aggregation table; A step of selecting
The route control means compares the evaluation of communication quality with the second wireless device from the wireless devices in the search space based on the communication state information aggregation table, and is within a certain threshold. And selecting a third wireless device having a height higher than that of the second wireless device based on the received position information;
The path control means sets the selected third wireless device as a wireless device that communicates next to the first wireless device in the route;
A communication path control method for a radio communication system, comprising: the base station transmitting path information including an address of the third radio apparatus to the first radio apparatus.
In a wireless communication system comprising one or more wireless devices and a base station, wherein each wireless device relays another wireless device and communicates according to a route to the base station,
Each of the wireless devices is
Position information acquisition means for acquiring own position information;
Position information transmitting / receiving means for receiving position information of another wireless device and transmitting its own position information;
Means for holding the acquired position information and the position information for holding the received position information of the other wireless device;
Communication state information acquisition means for acquiring information related to communication quality with other wireless devices;
Means for holding information on communication quality with the other received wireless device;
Path control means for obtaining a radio device to perform the next relay in the route of the base station from the radio device,
The route control means includes
When seeking a wireless device for the next relay from the wireless device,
Seeking a wireless device in a three-dimensional search space having a certain size including the wireless device;
Based on the information on the communication quality with the other wireless device, the wireless device having the best communication quality in communication with the wireless device is selected from the wireless devices in the search space,
Based on the information on the communication quality with the other wireless device, the communication quality with the wireless device having the best communication quality in the communication with the wireless device is evaluated from the wireless devices in the search space. In comparison, based on the received position information and based on the received position information, a wireless device having a height higher than that of the wireless device having the best communication quality with the wireless device is relayed from the wireless device. Select as a wireless device to
A wireless communication system, wherein a wireless device selected as the relaying wireless device is a wireless device that communicates with the wireless device next to the route.
In a communication path control method of a wireless communication system, comprising one or more wireless devices and a base station, each wireless device communicating with another wireless device according to a route to the base station,
Each of the wireless devices is
Position information acquisition means for acquiring own position information;
Position information transmitting / receiving means for receiving position information of another wireless device and transmitting its own position information;
A position information table that holds the acquired position information of the device and the received position information of the other wireless device;
Communication state information acquisition means for acquiring information related to communication quality with other wireless devices;
A communication state information table that holds information about the acquired communication quality;
Path control means for obtaining a radio device to perform the next relay in the route of the base station from the radio device,
The wireless device acquires the position information of itself by the position information acquisition means;
The wireless device holding the acquired location information of the device in the location information table;
Receiving the position information of the other wireless device by the position information transmitting / receiving means;
The wireless device holding the received location information of the other wireless device in the location information table;
The wireless device acquires information on communication quality with other wireless devices by the communication state information acquisition means;
The wireless device holding information on the acquired communication quality in the communication state information table;
The wireless device holding the position information of the wireless apparatus in the position information table;
When the wireless device seeks a wireless device to relay next, the route control means seeks a wireless device in a three-dimensional search space having a certain size including the wireless device,
The route control means selects a wireless device having the best communication quality in communication with the wireless device from wireless devices in the search space based on the communication state information table,
Based on the communication state information table, the route control means compares the evaluation of communication quality with the wireless device having the best communication quality with the wireless device among the wireless devices in the search space. Based on the received position information, a wireless device having a height higher than that of the wireless device having the best communication quality in communication with the wireless device is relayed from the wireless device. Selecting as a wireless device to perform,
And a step of making the wireless device selected as the relaying wireless device a wireless device that communicates next to the wireless device on the route.