JP2006140821A - Wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the risk of transmission data collision between slave units in its own system and in another system. <P>SOLUTION: A master unit 2 is provided with a time slot assignment inhibit unit 20c. The time slot assignment inhibit unit 20c accesses a time slot table (a table indicating a present operating state of a time slot in one period T) TB, designates a time slot at a reception point of time of measurement data from a slave unit of the other system for a busy slot, and inhibits the assignment of the busy slot to the slave unit of its own system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless communication system between a parent device and a child device that transmits and receives data wirelessly.

  Conventionally, a wireless sensor system as shown in FIG. 25 has been used as this type of wireless communication system (see, for example, Patent Document 1). In the figure, 1 (1-1 to 1-n) is a slave unit (transmitter), 2 is a master unit (receiver), 3 is a controller, and the slave unit 1 is connected to the master unit 2 via a wireless line. The As the subunit | mobile_unit 1, wireless sensors, such as a temperature sensor, a humidity sensor, a flow meter, and a watt-hour meter, are used. The master unit 2 receives the measurement data from the slave unit 1 and transfers it to the controller 3. The controller 3 performs control calculation based on the measurement data, and controls air conditioning equipment such as a VAV (variable air volume adjustment unit) and an FCU (fan coil unit).

  In such a wireless communication system, measurement data is transmitted from the slave unit 1 to the master unit 2 at a constant period T in order to perform smooth control without hunting. That is, the slave units 1-1 to 1-n are registered in the master unit 2, thereby providing a parent-child connection relationship (parent-child relationship) between the master unit 2 and the slave units 1-1 to 1-n. The transmission timing is shifted from the slave units 1-1 to 1-n, and the measurement data is periodically sent to the master unit 2. The transmission timing of measurement data from the slave units 1-1 to 1-n is designated by the master unit 2. That is, base unit 2 designates the transmission timing of the measurement data to slave units 1-1 to 1-n so that the reception timings of the measurement data do not overlap.

  The base unit 2 is often connected to a stand-alone controller 3. That is, a plurality of stand-alone controllers 3 are installed on the same floor, the master unit 2 is connected to each of the stand-alone controllers 3, and the plurality of slave units 1 are connected to the master unit 2 via a wireless line. System configuration is often taken. In this case, a large number of master units 2 and slave units 1 that are not connected to the network exist on the same floor. That is, there are a plurality of wireless communication systems that are not connected to each other on the same floor.

  FIG. 26 shows an example in which two wireless communication systems are provided close to each other. In the figure, reference numeral 100 denotes a first wireless communication system, in which a master unit 2A is connected to a stand-alone controller 3A, and slave units 1A1 to 1An are connected to the master unit 2A via a wireless line. Reference numeral 200 denotes a second wireless communication system in which the parent device 2B is connected to the stand-alone controller 3B, and the child devices 1B1 to 1Bn are connected to the parent device 2B via a wireless line.

Japanese Patent Laid-Open No. 8-130783

  However, in the wireless communication system shown in FIG. 26, when the use frequency band of the handset 1 in the first wireless communication system 100 and the second wireless communication system 200 is the same (usually the same), the radio wave There is a risk of failure.

  For example, when the slave unit 1An in the wireless communication system 100 is provided at a position overlapping the communication area of the wireless communication system 200, for example, measurement data from the slave unit 1B1 in the wireless communication system 200 and the slave unit 1An in the wireless communication system 100 There is a possibility that the measurement data collides, and the measurement data from the slave unit 1B1 is not received by the master unit 2B.

  Furthermore, if the transmission systems of measurement data from the slave unit 1 are the same in the wireless communication systems 100 and 200, once the transmission timing matches and a collision occurs, the collision continues for a long period of time and communication is impossible. A fatal problem occurs.

  Products that eliminate the problems of adjusting antenna directivity and restricting the installation position in consideration of the distance from the noise source, increasing the wireless output, increasing the transmission distance, and simplifying the installation adjustment of wireless devices There is a demand for realizing the specifications. If it is going to respond to such a request, it will become easy to generate radio wave interference in a wider range, and the probability that a collision will occur increases.

The following two methods are conceivable as methods for solving the occurrence of the radio wave interference.
(1) Synchronize among a plurality of systems, and transmit at timed timing so that no collision occurs. That is, the transmission timings are shifted so that no collision occurs by connecting the parent devices to each other via a wired or wireless network and synchronizing the parent devices.
(2) Instead of a fixed transmission cycle, data transmission is performed by shifting the transmission cycle with a random number different for each system. For example, different random numbers are generated for each slave unit, and the transmission cycle is varied based on the random numbers.

However, in the method (1) described above, when there is essentially no point in connecting the parent machines to the network other than synchronizing, the following cases are obtained depending on whether the network connection is wired or wireless. Problems arise.
[When connecting to a wired network]
Extra wiring and construction costs are required.
[When connecting to a wireless network]
Since communication between the parent device and the parent device increases in addition to communication between the parent device and the child device, if communication is performed in the same frequency band, the probability of occurrence of radio wave interference increases due to increased data to be communicated. In addition, a wireless slave unit normally uses a battery as a power source, but this method has a demerit that the communication protocol becomes complicated and the battery life is shortened.
Although a method of performing communication between the parent device and the parent device in a frequency band different from that between the parent device and the child device is also conceivable, the product cost increases because two wireless lines are required.

  In the case of the above method (2), the continuation of the collision of the transmission data between the slave units between the systems is prevented, but the possibility of the collision does not become zero. In addition, it is necessary to perform redundant processing such as retransmission, which also has a demerit of shortening the battery life of the slave unit.

  The present invention has been made to solve such a problem. The object of the present invention is to eliminate the possibility of collision of transmission data between slave units between systems without connecting the master units to a network. An object of the present invention is to provide a wireless communication system capable of

  In order to achieve such an object, the present invention (Claim 1 (first invention)) includes a master unit and a master unit and a slave unit that transmits and receives data wirelessly. A unit that divides the period T into time slots, and assigns the time slot to a slave unit of a wireless communication system to which the device belongs, and receives data from a slave unit of another wireless communication system, A time slot assignment prohibiting means for designating a time slot at the time of data reception as a busy slot and prohibiting assignment of the busy slot to a slave unit of the wireless communication system to which the busy slot belongs, and a slave unit of the wireless communication system to which the self belongs Means for notifying the time slot allocated to the slave unit as a transmission slot for data to the slave unit.

  In the present invention, when the master unit receives data from a slave unit of another wireless communication system (another system), it designates the time slot at the time of receiving the data as a busy slot, and the busy slot belongs to itself. Prohibit assignment of wireless communication system (own system) to slave units. When assigning a time slot to a child device of its own system, the parent device assigns a time slot other than the busy slot to the child device. As a result, in the local system, the use of the time slot at the time when data is sent from the slave unit of the other system is avoided, and there is a risk of collision of transmission data between the local system and the slave unit of the other system. This disappears.

  Means for checking whether the reception timing of data from the slave unit of the wireless communication system to which the master unit belongs is within an allowable range within the time slot assigned to the slave unit that is the transmission source of the data in the master unit; If the data reception timing is out of the allowable range, a means for instructing the transmission slave unit to adjust the data transmission timing is provided so that the data reception timing falls within the allowable range. (Claim 2 (second invention)), it becomes possible to prevent repeated collision of transmission data between slave units in the own system due to a shift in transmission timing.

  In addition, when trying to designate a time slot at the time of receiving data from a slave unit of another radio communication system as a busy slot, the time slot may already be assigned to the slave unit of its own radio communication system. . According to the present invention (claim 3 (third invention)), in such a case, an unallocated (unused) time slot other than the busy slot is allocated to the slave unit.

  According to the present invention, data is received from a slave unit of another wireless communication system, the time slot at the time of receiving the data is designated as a busy slot, and the assignment of this busy slot to the slave unit of its own system is prohibited. As a result, in the local system, the use of the time slot when data is sent from the slave unit of another wireless communication system can be avoided, and the slave units between the systems can be connected without connecting the master units to the network. The possibility of collision of transmission data can be eliminated.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a wireless communication system showing an embodiment of the present invention. 25, the same reference numerals as those in FIG. 25 denote the same or equivalent components as those described with reference to FIG. 25, and description thereof will be omitted. In this embodiment, a simple configuration will be described with an example in which the slave unit 1 includes two slave units 1A1 and 1A2 as a system at the start of operation.

  The principal part of the subunit | mobile_unit (transmitter) 1 is shown to Fig.2 (a). The subunit | mobile_unit 1 is provided with the radio | wireless communication control part 1a, the sensor measurement part 1b, the power saving management part 1c, and the transmission timing adjustment part 1d. The wireless communication control unit 1a controls communication with the parent device 2. The sensor measurement unit 1b measures temperature, humidity, and the like, and sends the measurement data to the wireless communication control unit 1a. The power saving management unit 1 c manages power consumption in the slave unit 1. The transmission timing adjustment unit 1d receives a transmission timing adjustment instruction (described later) from the parent device 2, and adjusts the transmission timing of measurement data from the child device 1 to the parent device 2.

  FIG. 2B shows a main part of the parent device (receiver) 2. The base unit 2 includes a host communication unit 2a, a radio communication control unit 2b, and a measurement data management unit 2c. The upper communication unit 2 a controls communication with the controller 3. The wireless communication control unit 2b controls communication with the handset 1. The measurement data management unit 2c manages measurement data from the slave unit 1 via the wireless communication control unit 2b.

In addition, the subunit | mobile_unit 1 and the main | base station 2 are implement | achieved by the hardware which consists of a processor and a memory | storage device, and the program which implement | achieves various functions in cooperation with these hardware.
Hereinafter, the operation at the start of operation in this system will be described in accordance with the sequence shown in FIG.

[Initial processing]
Assuming that the slave unit 1A1 (# 1), the slave unit 1A2 (# 2), and the master unit 2A (# 1) are turned off as a state before the operation is started. When the power of the parent device 2A is turned on from such a state (FIG. 3: arrow (1)), the parent device 2A starts the initial process (FIG. 3: periods t1 to t2).

  In this initial process, base unit 2A performs carrier sense for the frequency band used in its own communication area during period T. That is, during the period T, it is checked whether or not there is a slave unit (carrier) that communicates with the master unit 2A in the used frequency band. Then, based on the result of the carrier sense, a time slot table is created in which one division unit obtained by time division of the period T is a time slot.

  FIG. 4 shows a flowchart of the initial process executed by base unit 2A. When power is turned on, base unit 2A starts counting time of a timer of one period T, and a time slot table (table indicating a time slot usage state) in which one period T is divided into a plurality of time slots. Is set (step 100). Subsequently, base unit 2A sets a timer for one cycle T (step 101), and repeats the time slot table creation process in step 102 until a timeout of the timer for one cycle T is detected in step 103.

  FIG. 6A illustrates the time slot table TBA in this case. In this time slot table TBA, as will be described later, information about the usage status of each time slot (S1 to S10) in one period T is written. In the initial state, the time slots S1 to S10 are all unused (empty).

  FIG. 5 shows a flowchart of the time slot table creation processing in step 102. In this time slot table creation process, base unit 2A performs carrier sense (step 201), and when a carrier in the used frequency band is detected (YES in step 202), determines whether the carrier is a slave unit of its own system. Confirm (step 203). If it is not a slave unit of its own system (NO in step 203), that is, if it is a slave unit of another system, the time slot at the time of receiving measurement data from that slave unit is set (designated) as a busy slot (step 204). ). If it is a slave unit of the own system (YES in step 203), the time slot at the time of reception of measurement data from the slave unit is set as a time slot in use (step 205).

  In this example, there are no slave units in other systems, and since the slave units 1-1 and 1-2 of the own system are both turned off, no carrier is detected. Therefore, in the time slot table TBA created in step 102, the information written in the time slots S1 to S10 does not change as shown in FIG.

[Normal mode]
When the power of the child device 1A1 is turned on (FIG. 3: arrow (2)), the child device 1A1 sends a connection request to the parent device 2A (FIG. 3: arrow (3)). The base unit 2A receives the connection request from the slave unit 1A1 (FIG. 7: YES in step 301), confirms that the slave unit 1A1 is a slave unit of its own system (YES in step 302), and then timeslots. It is checked whether there is an empty time slot in the table TBA (FIG. 6B) (step 303). If it is a connection request from a slave unit of another system, nothing is done (NO in step 302). On the other hand, when the measurement data from the slave unit of another system is received (NO in step 300), the master unit 2A designates the time slot at the time of reception of the measurement data from the slave unit as the busy slot (step 308).

  If there is an empty time slot (YES in step 303), base unit 2A assigns an arbitrary empty time slot to slave unit 1A1 (step 304) and notifies the assigned time slot to slave unit 1A1 (step step). 305). If there is no empty time slot (NO in step 303), it is determined that there is an abnormality (step 306), and that fact is notified to the slave unit 1A1 (step 307).

  In this example, since all of the time slots S1 to S10 are empty, the parent device 2A assigns, for example, the time slot S2 as an arbitrary empty time slot to the child device 1A1 (FIG. 3: arrow (4)). The assigned time slot S2 is notified to the slave unit 1A1 (FIG. 3: arrow (5)).

  At this time, the parent device 2A writes information indicating that the child device 1A1 is in use in the time slot S2 in the time slot table TBA (FIG. 6 (c)). Slave unit 1A1 receives notification of time slot S2 from master unit 2A, and transmits measurement data to master unit 2A in the notified time slot S2 (FIG. 3: arrow (7)). The transmission is repeated with a period T.

  In this embodiment, the notification of the time slot S2 from the parent device 2A to the child device 1A1 is performed by the time ts2 from the notification timing of the time slot S2. In this case, the base unit 2A sets the time at the center of the time slot S2 of the next cycle as tTyp, calculates the time ts2 from the notification timing of the time slot S2 to the handset 1A1 to the time tTyp, and uses this time ts2 as the handset. Notify 1A1. The slave unit 1A1 receives the notification of the time ts2 from the master unit 2A, transmits the measurement data when the time ts2 has elapsed from the notification timing of the time ts2, and repeats the transmission of the measurement data at the period T.

  When the power of the slave unit 1A2 is turned on (FIG. 3: arrow (6)), the slave unit 1A2 sends a connection request to the master unit 2A (FIG. 3: arrow (8)). Base unit 2A receives a connection request from slave unit 1A2 (FIG. 7: YES in step 301), and checks whether there is an empty time slot in time slot table TBA (FIG. 6C) ( Step 303).

  In this case, since all except time slot S2 are empty, base unit 2A assigns, for example, time slot S5 as an arbitrary empty time slot to slave unit 1A2 (FIG. 3: arrow (9)), and the assigned time. The slot S5 is notified to the slave unit 1A2 (FIG. 3: arrow (10)). At this time, the parent device 2A writes information indicating that the child device 1A2 is in use in the time slot S5 in the time slot table TBA (FIG. 6 (d)). The slave unit 1A2 receives the notification of the time slot S5 from the master unit 2A, and transmits the measurement data to the master unit 2A in the notified time slot S5 (FIG. 3: arrow (12)).

[When another slave unit is sending measurement data at the time of connection request]
For example, when the power of the slave unit 1A2 is turned on (FIG. 3: arrow (6)) and the connection request is made from the slave unit 1A2 to the master unit 2A (FIG. 3: arrow (8)), unfortunately, The slave unit 1A1 may transmit measurement data to the master unit 2A.

[Operation example 1]
FIG. 8 shows an operation example 1 when another slave unit is transmitting measurement data at the time of a connection request. In this operation example 1, the slave unit 1A2 sends a connection request to the master unit 2A. At the same time, the slave unit 1A2 starts measuring the time for a slot wait timer (soft timer). If the slot wait timer times out, Wait for T to retry.

  In the example of FIG. 8, the measurement data from the slave unit 1A1 and the connection request from the slave unit 1A2 collide (FIG. 8: arrows (7) and (8)), and the master unit 2A has the measurement data from the slave unit 1A1. However, the connection request from the slave unit 1A2 is not transmitted. Therefore, time slot allocation is not performed in the master unit 2A, and the time slot notification from the master unit 2A to the slave unit 1A2 is not performed. For this reason, the slot waiting timer in the child device 1A2 times out.

  When the slot waiting timer times out, slave unit 1A2 waits for the elapse of period T from the time when this slot waiting timer times out, and again makes a connection request to parent unit 2A (FIG. 8: arrow (10)). In this case, since the transmission timing of the connection request from the slave unit 1A2 is delayed by the time measured by the slot wait timer from the previous one, the measurement data (FIG. 8: arrow (9)) from the slave unit 1A1 and the slave unit 1A2 Will not collide with other connection requests.

  Upon receiving a connection request from the slave unit 1A2, the master unit 2A assigns an arbitrary empty time slot to the slave unit 1A2, for example, assigns a time slot S5 (FIG. 8: arrow (11)), and the assigned time slot S5 Is notified to the slave unit 1A2 (FIG. 8: arrow (12)). The slave unit 1A2 receives the notification of the time slot S5 from the master unit 2A, and transmits the measurement data to the master unit 2A in the notified time slot S5 (FIG. 8: arrow (14)).

[Operation example 2]
FIG. 9 shows an operation example 2 when another slave unit is transmitting measurement data at the time of a connection request. In this operation example 2, before making a connection request from the child device 1A2 to the parent device 2A, carrier sense is performed in the child device 1A2, and when a carrier is detected, the connection request to the parent device 2A is canceled and the cycle T + α Wait for progress and retry.

  In the example of FIG. 9, since the slave unit 1A2 detects the slave unit 1A1 as a carrier (FIG. 9: arrow (8)), carrier sense fails and a connection request to the master unit 2A is not made. Therefore, the measurement data from the child device 1A1 and the connection request from the child device 1A2 do not collide, and the measurement data from the child device 1A1 is transmitted to the parent device 2A (FIG. 9: arrow (7)).

  When canceling the connection request, handset 1A2 waits for the elapse of cycle T + α from that point and makes a connection request to base unit 2A again. In this case, since the transmission timing of the connection request from the child device 1A2 is delayed by α from that of the previous time, the child device 1A1 is not detected as a carrier, and a connection request is sent from the child device 1A2 to the parent device 2A. (FIG. 9: arrow (11)).

  When receiving the connection request from the slave unit 1A2, the master unit 2A assigns, for example, a time slot S5 as an arbitrary empty time slot to the slave unit 1A2 (FIG. 9: arrow (12)), and assigns the assigned time slot S5 to the slave unit 1A2. The slave unit 1A2 is notified (FIG. 9: arrow (13)). The slave unit 1A2 receives the notification of the time slot S5 from the master unit 2A, and transmits the measurement data to the master unit 2A in the notified time slot S5 (FIG. 9: arrow (15)).

[Addition of handset]
FIG. 10 shows a sequence in the case where the slave unit 1A3 (# 3) is added to the system in operation with the powers of the slave units 1A1 and 1A2 turned on. When the child device 1A3 is added and the power is turned on (FIG. 10: arrow (1)), the child device 1A3 sends a connection request to the parent device 2A (FIG. 10: arrow (3)).

  In response to the connection request from the child device 1A3, the parent device 2A assigns, for example, a time slot S9 as an arbitrary empty time slot in the time slot table TBA (FIG. 6 (d)) to the child device 1A3 (FIG. 10: The arrow (4)) and the assigned time slot S9 are notified to the slave unit 1A3 (FIG. 10: arrow (5)). At this time, the parent device 2A writes information indicating that the child device 1A3 is in use in the time slot S9 in the time slot table TBA (FIG. 12A).

The slave unit 1A3 receives the notification of the time slot S9 from the master unit 2A, and transmits the measurement data to the master unit 2A in the notified time slot S9 (FIG. 10: arrow (9)).
If the slave unit 1A1 or 1A2 is transmitting measurement data at the time of the connection request, the slave unit 1A3 shifts the connection request transmission timing in the same manner as in the operation example 1 and operation example 2 described above, and retries. .

[Delete slave unit]
FIG. 11 shows a sequence in the case where the slave unit 1A2 is deleted from the operating system with the slave units 1A1 and 1A2 turned on. When the power of the slave unit 1A2 is turned off (FIG. 11: arrow (5)), the master unit 2A waits for the elapse of time (monitoring time) TC after receiving the last measurement data from the slave unit 1A2, and Stop assigning time slots to the machine 1A2.

  FIG. 13 shows a flowchart of the slave unit deletion process in the master unit 2A. When receiving the measurement data from slave unit 1A2 (YES in step 401), master unit 2A starts a slave unit deletion monitoring timer (soft timer) (step 402). If the next measurement data is received from the slave unit 1A2 before the slave unit deletion monitoring timer times out (YES in step 403), the slave unit deletion monitoring timer is cleared (step 406).

  If the slave unit deletion monitoring timer times out (YES in step 404), that is, if the next measurement data is not received from the slave unit 1A2 even after the monitoring time TC has elapsed, the time allocated to the slave unit 1A2 until then Let slot S5 be an empty time slot (step 405: FIG. 12B).

[Adjustment of measurement data transmission timing from slave unit]
FIG. 14 shows a flowchart of data transmission timing adjustment processing in base unit 2A. When the master unit 2A receives the measurement data from the slave unit 1 (step 501), the master unit 2A specifies the time slot assigned to the slave unit 1 (step 502).

  In the present embodiment, an allowable range TS is defined for the time slots S (S1 to S10) as shown in FIG. That is, the time at the center of the time slot S is set to tTyp, and the upper limit time tLim1 is set ahead and the lower limit time tLim2 is set behind this time tTyp.

  For example, it is assumed that the parent device 2A has received measurement data from the child device 1A1. In this case, the parent device 2A knows from the time slot table TBA at that time (FIG. 6D) that the time slot S2 is assigned to the child device 1A1. And the reception time of the measurement data from subunit | mobile_unit 1A1 is checked.

  If the reception time of measurement data from slave device 1A1 is earlier than upper limit time tLim1 in time slot S2 (YES in step 503), master device 2A has the reception time of measurement data from slave device 1A1 in time slot S2. The slave device 1A1 is instructed to adjust the transmission timing of the measurement data so that the time tTyp at the center of the current time is reached (step 504).

  If the reception time of the measurement data from the child device 1A1 is later than the lower limit time tLim2 in the time slot S2 (YES in step 505), the parent device 2A receives the measurement data from the child device 1A1 in the time slot S2. The slave device 1A1 is instructed to adjust the transmission timing of the measurement data so that the time tTyp at the center of the current time (step 506).

  In accordance with the instruction from the master unit 2A, the slave unit 1A1 approaches the center time tTyp of the time slot S2 by advancing or delaying the transmission timing of the measurement data by the time designated by the master unit 2A. Needless to say, it is not necessary to accurately match the reception timing of the measurement data from the slave unit 1A1 with the central time tTyp in the time slot S2, and the reception time of the measurement data from the slave unit 1A1 is assigned to itself. It only has to be within the allowable range TS in the time slot S2. By adjusting the transmission timing, repeated transmission data collision between the slave units 1 in the wireless communication system 100 due to the transmission timing shift is prevented.

[Addition of wireless communication system]
FIG. 16 shows an example in which a radio communication system 200 is provided close to the radio communication system 100 in operation. In this example, the slave unit 1A2 of the radio communication system 100 is provided at a position overlapping the communication area of the radio communication system 200, and the measurement data from the slave unit 1A2 is also received by the master unit 2B of the radio communication system 200. It shall be said that. The wireless communication system 200 is assumed to be in a state before the operation is started with the power of the parent device 2B and the child device 1B1 turned off.

[Initial processing]
In the wireless communication system 200 (own system), when the power of the parent device 2B is turned on (FIG. 17: arrow (1)), the parent device 2B starts the initial process (FIG. 17: periods t1 to t2). In this initial process, base unit 2B performs carrier sense of the used frequency band in its own communication area during period T. That is, during the period T, it is checked whether or not there is a slave unit (carrier) that communicates with the master unit 2B in the used frequency band. Then, based on the result of the carrier sense, a time slot table is created in which one division unit obtained by time division of the period T is a time slot.

  This initial process is performed according to the flowchart of FIG. When power is turned on, base unit 2B starts counting time of a timer of one period T, and a time slot table (table indicating a time slot usage state) in which one period T is divided into a plurality of time slots. Is set (step 100). Subsequently, base unit 2B sets a timer of one cycle T (step 101), and repeats the time slot table creation processing in step 102 until a timeout of the timer of one cycle T is detected in step 103.

  FIG. 18A illustrates the time slot table TBB in this case. In this time slot table TBB, information on the usage status of each time slot (S1 to S10) in one period T is written. In the initial state, the time slots S1 to S10 are all unused (empty).

  FIG. 5 shows a flowchart of the time slot table creation processing in step 102. In this time slot table creation process, base unit 2B performs carrier sense (step 201), and when a carrier in the used frequency band is detected (YES in step 202), determines whether the carrier is a slave unit of its own system. Confirm (step 203). If it is not a slave unit of its own system (NO in step 203), that is, if it is a slave unit of another system, the time slot at the time of receiving measurement data from the slave unit is designated as a busy slot (step 204). If it is a slave unit of the own system (YES in step 203), the time slot at the time of reception of measurement data from the slave unit is set as a time slot in use (step 205).

  In this example, since the handset 1A2 of the wireless communication system 100 (another system) is detected as a carrier (FIG. 17: arrow (4)), the time slot table TBB created in step 102 is shown in FIG. ), The time slot S5 at the time of reception of the measurement data from the slave unit 1A2 is designated as a busy slot.

[Normal mode]
When the power of the child device 1B1 is turned on (FIG. 17: arrow (8)), the child device 1B1 sends a connection request to the parent device 2B (FIG. 17: arrow (10)). The base unit 2B receives a connection request from the slave unit 1B1 (FIG. 7: YES in step 301), confirms that the slave unit 1B1 is a slave unit of its own system (YES in step 302), and then timeslots. It is checked whether there is an empty time slot in the table TBB (FIG. 18B) (step 303). If it is a connection request from a slave unit of another system, nothing is done (NO in step 302). On the other hand, when the measurement data is received from the slave unit of another system (NO in step 300), the master unit 2B designates the time slot when the measurement data is received from the slave unit as the busy slot (step 308).

  If there is an empty time slot (YES in step 303), base unit 2B assigns an arbitrary empty time slot to slave unit 1B1 (step 304), and notifies the assigned time slot to slave unit 1B1 (step step). 305). If there is no empty time slot (NO in step 303), it is determined that there is an abnormality (step 306), and that fact is notified to the slave unit 1B1 (step 307).

  In this example, since the time slot S5 other than the busy slot, that is, the time slots S1 to S4 and S6 to S10 are empty, the parent device 2B uses, for example, the time slot S2 as a child device as an arbitrary empty time slot. 1B1 is assigned (FIG. 17: arrow (11)), and the assigned time slot S2 is notified to the slave unit 1B1 (FIG. 17: arrow (12)).

  At this time, the parent device 2B writes information indicating that the child device 1B1 is in use in the time slot S2 in the time slot table TBB (FIG. 18 (c)). The slave unit 1B1 receives the notification of the time slot S2 from the master unit 2B, and transmits measurement data to the master unit 2B in the notified time slot S2 (FIG. 17: arrow (15)). The transmission is repeated with a period T.

  As can be seen from this operation, in this embodiment, measurement data from the slave unit 1 of the other system 100 is received, the time slot at the time of reception of the measurement data is designated as a busy slot, and the busy slot itself is specified. Since the assignment of the system 200 to the slave unit 1 is prohibited, the use of the time slot when the measurement data is sent from the slave unit 1 of the other system 100 can be avoided, and the master units 2A and 2B are networked together. Thus, the possibility of collision of transmission data between slave units between systems can be eliminated.

[When the slave unit of another system is sending measurement data at the time of connection request]
For example, when the power of the slave unit 1B1 is turned on (FIG. 17: arrow (8)) and the connection request is made from the slave unit 1B1 to the master unit 2B (FIG. 17: arrow (10)), unfortunately, The slave device 1A2 of the other system 100 may transmit measurement data.

[Operation example 1]
FIG. 20 shows an operation example 1 when the slave unit of another system is transmitting measurement data when a connection request is made. In this operation example 1, at the same time as sending a connection request from the slave unit 1B1 to the master unit 2B, the slave unit 1B1 starts counting the time for a slot wait timer (soft timer), and if the slot wait timer times out, Wait for T to retry.

  In the example of FIG. 20, the measurement data from the slave unit 1A2 of the other system 100 and the connection request from the slave unit 1B1 of the own system 200 collide (FIG. 20: arrows (11) and (12)), and the master unit 2B No connection request is transmitted from the slave unit 1B1. Therefore, time slot allocation is not performed in base unit 2B, and time slot notification is not performed from base unit 2B to handset 1B1. For this reason, the slot waiting timer in the child device 1B1 times out.

  When the slot wait timer times out, slave unit 1B1 waits for the elapse of period T from the time when this slot wait timer times out, and again makes a connection request to base unit 2B (FIG. 20: arrow (16)). In this case, since the transmission timing of the connection request from the slave unit 1B1 is delayed by the time measured by the slot wait timer from the previous one, measurement data from the slave unit 1A2 of the other system 100 (FIG. 20: arrow (15)) ) And the connection request from the slave unit 1B1 of the own system 200 do not collide.

  When receiving the connection request from the slave unit 1B1, the master unit 2B allocates, for example, a time slot S2 as an arbitrary empty time slot to the slave unit 1B1 (FIG. 20: arrow (17)), and assigns the allocated time slot S2 to the slave unit 1B1. The slave unit 1B1 is notified (FIG. 20: arrow (18)). The slave unit 1B1 receives the notification of the time slot S2 from the master unit 2B, and transmits measurement data to the master unit 2B in the notified time slot S2 (FIG. 20: arrow (19)).

[Operation example 2]
FIG. 21 shows an operation example 2 when the slave unit of another system is transmitting the measurement data at the time of the connection request. In this operation example 2, before making a connection request from the child device 1B1 to the parent device 2B, carrier sense is performed in the child device 1B1, and when a carrier is detected, the connection request to the parent device 2B is canceled and the cycle T + α Wait for progress and retry.

  In the example of FIG. 21, since the slave unit 1B1 detects the slave unit 1A2 of the other system 100 as a carrier (FIG. 21: arrow (12)), carrier sense fails and no connection request to the master unit 2B is made. Therefore, the measurement data from the child device 1A2 of the other system 100 and the connection request from the child device 1B1 of the own system 200 do not collide (FIG. 21: arrow (11)).

  When the connection request is canceled, the slave unit 1B1 waits for the elapse of the cycle T + α from that point and makes a connection request to the master unit 2B again. In this case, since the transmission timing of the connection request from the child device 1B1 is delayed by α from the previous time, the child device 1A2 of the other system 100 is not detected as a carrier, and the connection request from the child device 1B1 to the parent device 2B is lost. Is sent (FIG. 21: arrow (17)).

  Upon receiving the connection request from the slave unit 1B1, the master unit 2B allocates, for example, a time slot S2 as an arbitrary empty time slot to the slave unit 1B1 (FIG. 21: arrow (18)), and assigns the allocated time slot S2 to the slave unit 1B1. The slave unit 1B1 is notified (FIG. 21: arrow (19)). The slave unit 1B1 receives the notification of the time slot S2 from the master unit 2B, and transmits the measurement data to the master unit 2B in the notified time slot S2 (FIG. 21: arrow (20)).

[Addition of handset]
FIG. 22 shows a sequence in the case where the slave unit 1A3 (# 3) is added to another system 100 that is operating with the slave units 1A1 and 1A2 turned on. In addition, this subunit | mobile_unit 1A3 shall be provided in the position which overlaps with the communication area of the radio | wireless communications system 200. FIG.

  When the child device 1A3 is added and the power is turned on (FIG. 22: arrow (1)), the child device 1A3 sends a connection request to the parent device 2A (FIG. 22: arrow (4)). In response to the connection request from the child device 1A3, the parent device 2A assigns, for example, a time slot S9 as an arbitrary empty time slot in the time slot table TBA (FIG. 6 (d)) to the child device 1A3 (FIG. 22: The arrow (5)) and the assigned time slot S9 are notified to the slave unit 1A3 (FIG. 22: arrow (7)). At this time, the parent device 2A writes information indicating that the child device 1A3 is in use in the time time slot S9 in the time slot table TBA (FIG. 12 (a)).

  Slave unit 1A3 receives notification of time slot S9 from master unit 2A, and transmits measurement data to master unit 2A in the notified time slot S9 (FIG. 22: arrow (14)). Measurement data from the slave unit 1A3 of the other system 100 is also received by the master unit 2B of the own system 200. When the master unit 2B of the own system 200 receives the measurement data from the slave unit 1A3 of the other system 100, the time slot at the time of reception of this measurement data is designated as a busy slot (FIG. 22: arrow (16), FIG. 19 (a)).

  At this time, the time slot at the time of reception of measurement data from the slave unit 1A3 of the other system 100 may already be assigned to the slave unit 1 of the own system 200. In this case, there is a possibility that the measurement data from the child device 1A3 of the other system 100 and the measurement data from the child device 1 of the own system 200 may collide. In this case, since the master unit 2B cannot receive any data, the slave unit 1 detects that the communication with the master unit 2B is not successful, shifts the time slot slightly (with carrier sense), and Request reassignment.

[Delete slave unit]
FIG. 23 shows a sequence in the case where the slave unit 1A2 is deleted from the other system 100 in operation with the slave units 1A1 and 1A2 turned on.

  When the power of the slave unit 1A2 is turned off (FIG. 23: arrow (9)), the master unit 2A of the other system 100 receives the last measurement data from the slave unit 1A2 and the time (monitoring time) TC Waiting for the passage of time, the assignment of the time slot to the child device 1A2 is stopped. The master unit 2B of the own system 200 waits for the elapse of time (monitoring time) TC from the reception of the last measurement data from the slave unit 1A2, and then the time slot when the measurement data is received from the slave unit 1A2. Stop specifying a busy slot for.

  That is, when the master unit 2A of the other system 100 receives the measurement data from the slave unit 1A2 (FIG. 13: YES in step 401), it starts the slave unit deletion monitoring timer (step 402). If the slave unit deletion monitoring timer times out (YES in step 404), that is, if the next measurement data is not received from the slave unit 1A2 even after the monitoring time TC has elapsed, the time allocated to the slave unit 1A2 until then Let slot S5 be an empty time slot (step 405: FIG. 12B).

  When the master device 2B of the own system 200 receives the measurement data from the slave device 1A2 of the other system 100 (YES in step 401), the master device 2B starts a slave device deletion monitoring timer (step 402). If the slave unit deletion monitoring timer times out (YES in step 404), that is, if the next measurement data is not received from the slave unit 1A2 of the other system 100 even after waiting for the monitoring time TC to pass, The time slot S5 that has been a busy slot until that time is the time slot when the measurement data is received from the slave unit 1A2 is set as an empty time slot (step 405: FIG. 19B).

  FIG. 24 shows a functional block diagram of the main part of the base unit 2. The radio communication control unit 2b of the base unit 2 includes a carrier detection unit 20a, a time slot allocation unit 20b, a time slot allocation prohibition unit 20c, a reception timing check unit 20d, a notification unit 20e, and a time slot table TB. I have. The carrier detection unit 20a includes a first carrier detection unit 20a1 that detects a carrier (child device) of its own system and a second carrier detection unit 20a2 that detects a carrier of another system.

  When the first carrier detection unit 20a1 receives the connection request from the slave unit of its own system, the first carrier detection unit 20a1 sends the connection request to the time slot allocation unit 20b. The time slot assigning unit 20b accesses the time slot table TB, assigns any empty time slot in the time slot table TB to the child device, and notifies the child device via the notification unit 20e of the assigned time slot. To do. In addition, information indicating that the child device is in use is written in the assigned time slot in the time slot table TB.

  Further, when the first carrier detection unit 20a1 receives measurement data from the slave unit of its own system, the first carrier detection unit 20a1 sends the reception timing of the measurement data to the reception timing check unit 20d. The reception timing check unit 20d accesses the time slot table TB and knows the time slot assigned to the slave unit that is the transmission source of the measurement data. Then, it is checked whether the reception timing of the measurement data is within the allowable range in the time slot assigned to the transmission source slave unit. If it is out of the allowable range, the reception timing of the measurement data is within the allowable range. So that the transmission timing of the data is adjusted to the transmission source slave unit via the notification means 20e.

  When the second carrier detection unit 20a2 receives the measurement data from the slave unit of another system, the second carrier detection unit 20a2 sends the reception timing of the measurement data from the slave unit to the time slot allocation prohibition unit 20c. The time slot allocation prohibition unit 20c accesses the time slot table TB, designates the time slot at the time of receiving measurement data from the slave unit as a busy slot, and prohibits the allocation of this busy slot to the slave unit of its own system. .

  In this embodiment, in order to extend the battery life of the handset 1 that operates on a battery, the handset 1 is allowed to perform unidirectional communication as much as possible. When synchronizing with the time slot in communication between the slave unit and the master unit, the slave unit will normally synchronize with the beacon signal etc. emitted by the master unit. Need to be received, and low power consumption cannot be achieved. On the other hand, in the present embodiment, the parent device 2 takes over control for synchronizing the child device 1. Although it is necessary for the slave unit 1 to adjust timing in accordance with an instruction from the master unit 2, the slave unit 1 only needs to instantaneously turn on the reception circuit immediately after data transmission, and a considerable reduction in power consumption can be achieved.

It is a block diagram of the radio | wireless communications system which shows one embodiment of this invention. It is a block diagram which shows the principal part of the main | base station used for this radio | wireless communications system, and a subunit | mobile_unit. It is a sequence diagram which shows the operation | movement at the time of the operation start in this radio | wireless communications system. It is a flowchart of the initial process which a main | base station performs at the time of an operation start. It is a flowchart of a creation process of a time slot table. It is a figure which shows the change of the write information to a time slot table. It is a flowchart of the slot allocation process in the parent machine in the normal mode. It is a sequence diagram which shows the operation example 1 when the other subunit | mobile_unit is transmitting measurement data at the time of a connection request | requirement. It is a sequence diagram which shows the operation example 2 when the other subunit | mobile_unit is transmitting measurement data at the time of a connection request | requirement. It is a sequence diagram in the case of adding a slave unit. It is a sequence diagram in the case of deleting a child machine. It is a figure which shows the change of the write information to the time slot table at the time of adding and deleting a subunit | mobile_unit. It is a flowchart of the deletion processing of the child device in the parent device. It is a flowchart of a data transmission timing adjustment process in the master unit. It is a figure which shows the tolerance | permissible_range of the reception timing of the measurement data defined in a time slot. It is a figure which shows the example which provided another radio | wireless communications system (own system) adjacent to the radio | wireless communications system (other system) in operation. It is a sequence diagram which shows the operation | movement at the time of the operation start in this radio | wireless communications system. It is a figure which shows the change of the write information to the time slot table in the main | base station of an own system. It is a figure which shows the change of the write information to the time slot table in the main | base station of the own system at the time of adding and deleting a subunit | mobile_unit to another system. It is a sequence diagram which shows the operation example 1 when the subunit | mobile_unit of other systems is transmitting measurement data at the time of a connection request | requirement. It is a sequence diagram which shows the operation example 2 when the subunit | mobile_unit of other systems is transmitting measurement data at the time of a connection request | requirement. It is a sequence diagram in the case of adding a handset to another system. It is a sequence diagram in the case of deleting a handset from another system. It is a functional block diagram which shows the principal part of the main | base station in the radio | wireless communications system which concerns on this invention. It is a figure explaining the conventional radio | wireless communications system. It is a figure which shows the example which provided the two radio | wireless communications system close.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Wireless communication system (other systems), 200 ... Wireless communication system (own system), 1 (1A1 to 1An, 1B1 to 1Bn) ... Slave unit (transmitter), 2 (2A, 2B) ... Master unit (reception) Machine), 3 (3A, 3B) ... controller, 1a ... wireless communication control unit, 1b ... sensor measurement unit, 1c ... power saving management unit, 1d ... transmission timing adjustment unit, 2a ... upper communication unit, 2b ... wireless communication control Part, 2c ... measurement data management part, TBA, TBB ... time slot table, S1 to S10 ... time slot, TS ... allowable range, 20a ... carrier detection part, 20a1 ... first carrier detection part, 20a2 ... second carrier Detection unit, 20b ... Time slot allocation unit, 20c ... Time slot allocation prohibition unit, 20d ... Reception timing check unit, 20e ... Notification unit.

Claims (3)

In a wireless communication system comprising a parent device and a child device that transmits and receives data wirelessly with the parent device,
The base unit is
Means for assigning the time slot to a slave unit of the wireless communication system to which the time slot belongs as a time slot, which is a time division unit of the period T;
Receives data from a slave unit of another wireless communication system, designates the time slot at the time of receiving the data as a busy slot, and prohibits assignment of the busy slot to the slave unit of the wireless communication system to which it belongs Time slot allocation prohibition means;
A wireless communication system, comprising: means for notifying a slave unit of a wireless communication system to which the slave unit belongs a time slot assigned to the slave unit as a transmission slot for data to the slave unit. The wireless communication system according to claim 1, wherein
The base unit is
Means for checking whether or not the reception timing of data from the slave unit of the wireless communication system to which it belongs is within an allowable range within the time slot assigned to the slave unit that is the source of the data;
Means for instructing the slave unit of the transmission source to adjust the transmission timing of the data so that the reception timing of the data falls within the allowable range when the reception timing of the data is out of the allowable range; A wireless communication system comprising: The wireless communication system according to claim 1 or 2,
Means for assigning an unassigned time slot other than the busy slot to the slave unit when the time slot to be designated as the busy slot has already been assigned to the slave unit of its own wireless communication system; A wireless communication system.

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