JPWO2010064654A1 - Communication apparatus and communication method - Google Patents

Abstract

The present invention is a TDMA system in which a base station apparatus dynamically allocates a band, and is intended to realize a communication apparatus having a high communication efficiency by reducing a certain delay that must occur in uplink communication as much as possible. The communication device includes means for securing / releasing a fixed band for uplink communication of the slave station device in the master station device, and requesting the slave station device to secure the bandwidth when performing uplink communication to the master station device. And means for performing uplink communication using a fixedly secured band.

Description

  The present invention relates to a communication device that performs bidirectional data communication between a master station device and a plurality of slave station devices, and more particularly to a communication device or communication method that transmits data from a slave station device to a master station device. is there.

Conventionally, for example, a device that distributes data of home appliances such as a TV, a VCR, and a computer installed in a building such as a house is connected to an outlet without installing a dedicated line. : Power Line Communication), it is possible to connect to an external network such as the Internet connection or to configure a home network.
As an access control method for power line communication, there is a CSMA (Carrier Sense Multiple eAccess) method that is often used in general LANs. However, this method is largely affected by reflection and attenuation due to branching of the power line, and carrier sense is difficult. In many cases, a Time Division Multiple Access (TDMA) method is employed.

When the TDMA method is used, if a time slot is statically assigned to all slave station devices that may be connected by the master station device, communication is performed even if the slave station device is not connected or is connected. Slots allocated to no slave station devices are not used and are wasteful.
In order to solve this problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 2002-246963, the master station device changes the slot assignment according to the number of connected slave station devices and the master station device to the slave station device. Communication (downlink communication) and communication from the slave station device to the master station device (uplink communication) are divided by frequency band.
However, in this case, since the downlink communication and the uplink communication are divided, if either communication is smaller than the allocated band, there is a waste.
In order to avoid this waste, the master station apparatus may be provided with means for allocating slots in accordance with a bandwidth securing request from a slave station apparatus that is requested to transmit data.
However, in this case, if it is desired to perform uplink communication, it is necessary to make a bandwidth request for each frame, so that a certain delay always occurs.
The present invention can reduce the delay and realize power line communication that efficiently performs uplink communication.

JP 2002-246963 A

  In a TDMA (time division multiple access) system that dynamically allocates bandwidth, all allocation of communication bandwidth is managed by the scheduler of the master station apparatus. Therefore, when performing uplink communication, it is necessary to request the master station device to secure a necessary band for each time slot to which the slave station device is assigned in advance. In particular, when communication is performed by following the procedures of (1) connection establishment, (2) data communication, and (3) connection disconnection as in TCP / IP, bidirectional communication is required before actual data communication. The overhead is large and the communication performance is deteriorated.

  The present invention has been made to solve the above-described problems, and the master station device secures a band necessary for uplink communication of the slave station device as necessary, and thereafter It is an object of the present invention to provide an apparatus or a method capable of performing communication without requiring a bandwidth reservation when performing uplink communication.

  According to the communication apparatus or the communication method of the present invention, in the TDMA scheme in which bandwidth allocation is dynamically performed, when the slave station apparatus transmits data to the master station apparatus, the master station apparatus responds to a bandwidth securing request from the slave station apparatus. On the other hand, a fixed band for uplink communication is fixedly secured to the slave station apparatus, and the slave station apparatus uses the fixed band allocated by the master station apparatus for subsequent uplink communications. is there.

  According to the present invention, in a TDMA communication device that dynamically allocates bandwidth, when a slave station device transmits data to the master station device, the slave station device requests bandwidth reservation from the master station device. By securing a fixed bandwidth in accordance with a request from the station apparatus, there is an effect that a bandwidth securing request and a securing response in the subsequent uplink communication are unnecessary, and a certain delay necessary for the uplink communication is eliminated.

It is a figure which shows the connection structure of the communication apparatus concerning Embodiment 1 of this invention. It is a figure which shows an example of the frame structure between a master station apparatus and a slave station apparatus. It is a figure which shows an example of the procedure of the uplink communication from a child station apparatus to a parent station apparatus. It is a figure which shows an example of the procedure of the uplink communication from the child station apparatus to the parent station apparatus in the communication apparatus concerning Embodiment 1 of this invention. It is a figure which shows an example of the frame structure in the case of using fixed band allocation. It is a figure which shows an example of the process which allocates a fixed zone | band with a main | base station apparatus. It is an example of a table for managing which slave station device held by the master station device is allocated a fixed band. It is a figure which shows an example of a process of the slave station apparatus in the communication apparatus concerning Embodiment 1 of this invention. It is a figure which shows an example of the procedure which open | releases the fixed zone | band in the communication apparatus concerning Embodiment 2 of this invention. It is a figure which shows an example of the procedure which open | releases the fixed band in the communication apparatus concerning Embodiment 3 of this invention. It is a figure which shows an example of the procedure which open | releases the fixed band in the communication apparatus concerning Embodiment 4 of this invention. It is a figure which shows an example of the procedure which open | releases the fixed band in the communication apparatus concerning Embodiment 4 of this invention. It is an example of the table which manages the elapsed time since releasing the fixed band last time in the communication apparatus concerning Embodiment 5 of this invention for every slave station apparatus of the fixed band hold | maintained at a parent station apparatus. It is a communication apparatus concerning Embodiment 5 of this invention, It is a figure which shows an example of the procedure of the uplink communication from a child station apparatus to a parent station apparatus. It is a communication apparatus concerning Embodiment 5 of this invention, and is a figure which shows an example of the process which allocates a fixed zone | band with a main | base station apparatus. In the communication device according to the sixth embodiment of the present invention, the allocation status for each slave station device of the fixed band held by the master station device, the elapsed time since the last fixed bandwidth was released, and the priority for assigning the fixed bandwidth It is an example of the table which manages. In the communication apparatus concerning Embodiment 6 of this invention, it is a figure which shows an example of the order which a master station apparatus allocates a fixed zone | band with respect to a slave station apparatus. In the communication apparatus according to the sixth embodiment of the present invention, the master station apparatus is a diagram illustrating an example of processing for allocating a fixed band in accordance with a request from the slave station apparatus. In the communication apparatus concerning Embodiment 6 of this invention, it is a figure which shows an example of the process which a parent station apparatus sets the priority of a child station apparatus. In the communication apparatus concerning Embodiment 7 of this invention, it is a figure which shows an example of the structure of the band allocation request | requirement which a slave station apparatus transmits to a master station apparatus. In the communication apparatus according to the seventh embodiment of the present invention, the master station apparatus is a diagram showing an example of processing for allocating a fixed band in accordance with a request from the slave station apparatus. In a communication apparatus concerning Embodiment 7 of this invention, it is a figure which shows an example of the process which a slave station apparatus transmits data to a master station apparatus.

10 master station device 20, 21-2n slave station device

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a connection configuration of a communication apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a frame configuration for communication between the master station device and the slave station device.
FIG. 3 is a diagram illustrating a procedure in which the slave station device 20 performs data communication with the master station device 10.
FIG. 4 is a diagram illustrating a procedure in the case where the master station device 10 assigns a band in a fixed manner when the slave station device 20 performs data communication with the master station device 10.

As shown in FIG. 1, the communication apparatus according to the present embodiment includes a plurality of slave station apparatuses 20 to 2n connected to the master station apparatus 10 by the TDMA method.
Here, the master station device 10 is a device that transmits and receives data by connecting a plurality of slave station devices 20 to 2n by the TDMA method.
Communication between the master station device 10 and the slave station devices 20 to 2n is performed using the frames shown in FIG. The frame is divided into a plurality of slots, and data to be transmitted from a parent station device to a child station device and data to be transmitted from a child station device to the parent station device are assigned to each slot.

In the case of FIG. 2, data transmission from the master station device 10 to the slave station device 2x is assigned to the downlink communication unit, and data transmission from the slave station device 2x to the master station device 10 is assigned to the uplink communication unit.
Note that the master station device assigns “uplink communication or downlink communication” or “to which slave station device is communication” for each slot in the frame shown in FIG.
The number of slots allocated for uplink communication and downlink communication does not necessarily need to be fixed, and may be freely determined according to the communication state at that time.

The procedure when the slave station device 20 performs data communication with the master station device 10 will be described with reference to FIG.
When the slave station device 20 needs to transmit data to the master station device 20 (ST10), the slave station device 20 first requests the master station device 10 to secure a bandwidth necessary for transmitting data ( ST20).
When the master station device 10 receives the bandwidth securing request from the slave station device 20, the scheduler secures a necessary bandwidth in the next time slot (not necessarily all requested bandwidths) (ST11). At the same time, a bandwidth securing response is returned to the slave station device 20 (ST21).

When the slave station device 20 receives the bandwidth securing response ST21 from the master station device 10, the slave station device 20 starts data transmission using the bandwidth.
Note that the bandwidth reserved at this time is only valid for one time slot, so if all data could not be transmitted in one time slot or if continuous data transmission is required, It is necessary to transmit a bandwidth securing request for data transmission to the master station device 10 at the same time (ST22).
For this reason, a bandwidth securing request (ST20, ST22) is always made at the start of data transmission, and data transmission (ST22, ST23) is performed after waiting for a bandwidth securing response (ST21). A time slot delay will occur.

Next, a data transmission procedure from the slave station device 20 to the master station device 10 in the communication device according to the present embodiment will be described with reference to FIG.
When the slave station apparatus 20 needs to transmit data to the master station apparatus 20 (ST10), first, the slave station apparatus 20 requests the master station apparatus 10 for a band necessary for transmitting data (ST20). ).
When receiving the bandwidth securing request from the slave station device 20, the master station device 10 secures the requested bandwidth fixedly (ST111) and returns a fixed bandwidth securing response to the slave station device 20. (ST31).
When receiving the fixed band securing response ST31 from the master station apparatus 10, the slave station apparatus 20 starts data transmission using the band (ST23).
When the data transmission is completed (ST13), the slave station device 20 makes a request for releasing the fixed bandwidth secured to the master station device 10 (ST32). When the master station device 10 receives the request for releasing the fixed bandwidth, the slave station device 10 The fixed band reserved for the device 20 is released (ST112), and a fixed band release response (ST33) is returned.

Details of this processing will be described with reference to FIGS.
FIG. 6 is a diagram illustrating a process of assigning a fixed band in the master station device 10.
When receiving the bandwidth securing request from the slave station device 20 (ST60), the master station device 10 confirms whether or not there is a space in the fixed bandwidth area (ST61).
FIG. 5 shows a frame configuration for communication between the master station apparatus and the slave station apparatus when a fixed band is allocated.
A part of the uplink communication unit is assigned to the fixed band area, and a maximum value is determined in order to prevent a specific slave station device from occupying the uplink communication.
If there is free space in the fixed band area, a fixed band is allocated to the requested slave station device (ST62), and the correspondence between the slot in the frame and the slave station is registered in the management table shown in FIG. Thereafter, a fixed band securing response is transmitted to the slave station device (ST63).
If there is no free space in the fixed bandwidth area, it is further checked whether there is free space in the frame (ST610). If there is free space, a bandwidth is allocated (ST611), and a bandwidth securing response is transmitted to the slave station device (ST612). ) If there is no vacant frame, a bandwidth securing failure is transmitted to the slave station device (ST620).

FIG. 8 is a diagram illustrating processing when the slave station device 20 performs uplink communication with the master station device 10.
When the slave station device 20 needs to transmit data to the master station device 10 (ST80), it first checks whether a fixed band for itself is secured in the frame (ST81).
If the fixed bandwidth is not secured, a bandwidth securing request is sent to the master station device 10 (ST82).
If the reply from the master station device (ST83) is a fixed bandwidth securing response, data transmission is performed in the secured bandwidth (ST810). Data transmission is repeated as long as data to be transmitted remains (ST811).
When the data transmission is completed, a request for releasing the fixed band is made to the master station device 10 (ST812), and a response from the master station device is received (ST813).
When a bandwidth securing response is received from the master station device 10, data transmission is performed using the secured bandwidth (ST84), and when data remains (ST85), a bandwidth securing request is made again (ST82). If the master station device fails to secure the bandwidth, it waits for a certain period of time (ST820) and makes a bandwidth securing request again (ST82).

  As described above, when the master station device 10 has a plurality of slave station devices 20 to 2n connected by the TDMA method, the slave station device transmits data to the master station device from the slave station device to the master station device. In this case, it is necessary to request a bandwidth each time, and it is necessary to wait for a bandwidth securing request and a bandwidth securing response for each data transmission. When there is a reservation request, the base station apparatus side can allocate the uplink transmission band in a fixed manner, thereby eliminating the delay time of the next data transmission.

Embodiment 2. FIG.
In the first embodiment, the fixed band secured by the master station device 10 is released by a release request from the slave station device 20, but the timing at which the slave station device 20 next transmits data to the master station device 10 is The station apparatus 20 may not be able to predict.
Also, it can be considered that the slave station device 20 that has once transmitted data is highly likely to immediately transmit the next data.
Therefore, as shown in FIG. 9, the master station device 10 monitors the data transmission from the slave station device 20 and finally receives the data from the slave station device 20, so that a certain time (no transmission time 90) is received. After the elapse, the master station device 10 releases the fixed band assigned to the slave station device 20 (ST112) and transmits a fixed bandwidth release response (ST33) to the slave station device 20.

  As described above, by releasing the fixed band allocated to the slave station device 20 by the master station device 10 after the lapse of a predetermined time after the last data from the slave station device is received, the slave station device can When transmission is continuous, an effect is obtained that communication is possible without requesting a bandwidth reservation again.

Embodiment 3 FIG.
In Embodiment 2, if data transmission from the slave station device 20 continues, the fixed band secured by the master station device 10 is not released, and the slave station device 20 that continues data transmission occupies the bandwidth. However, as shown in FIG. 10, after the master station device 10 assigns a fixed band to the slave station device 20 (ST111), a fixed time assigned to the slave station device 20 after a certain time (maximum reserved time 100) has elapsed. By releasing the band (ST112), it is possible to prevent a specific slave station apparatus from occupying the band for uplink communication.

Embodiment 4 FIG.
In the third embodiment, the master station device 10 secures a fixed bandwidth until a certain time elapses regardless of whether or not the slave station device 20 transmits data.
Accordingly, there is a problem in that the bandwidth is secured even when the slave station device 20 is not performing data communication with the master station device 10, and the unused bandwidth is wasted.
As shown in FIGS. 11 and 12, the master station device 10 waits for the elapse of a fixed time (maximum reserved time 100) after allocating a fixed band to the slave station device 20 (ST111), and the slave station device 20 Until the fixed time (non-transmission time 90) elapses after data communication from the master station device 10 to the base station device 10 is completed, and when one of them elapses first, the fixed band is released (ST112).

  As described above, according to the fourth embodiment, a fixed time elapses after the master station device 10 allocates a fixed band to the slave station device 20, or a fixed time elapses after data communication is lost. Alternatively, when either condition is satisfied, the fixed band is released, so that the fixed band can be used efficiently.

Embodiment 5
In the first to fourth embodiments, the master station device 10 is assigned to the fixed bandwidth securing request from the slave station device 20 if there is a vacant fixed bandwidth to be assigned. In this case, the slave station having a high communication frequency is assigned. There is a problem that the establishment that a device receives fixed band allocation becomes high, and a slave station device with low communication frequency performs communication with a large transmission delay.
In the fifth embodiment, a slave station device management table (FIG. 13) is provided in the master station device 10, and for each slave station device (130), the fixed bandwidth allocation status (131) and the previous fixed bandwidth are released. When managing the time (132) and allocating the fixed bandwidth to the slave station device as shown in FIGS. 14 and 15, the fixed bandwidth allocated last time is released (ST112), and then a fixed time (band securing time 140). (ST151) and prohibiting allocation of a fixed band to a slave station device that has not passed a predetermined time, thereby allowing a slave station device that performs data communication during that time to be prohibited. Allows allocation of fixed bandwidth.

  As described above, according to the fifth embodiment, a slave station having a high communication frequency is prohibited by prohibiting the assignment of a fixed band for a certain period of time to a slave station apparatus that has once assigned a fixed band to the master station apparatus 10. This has the effect of preventing the device from occupying a fixed bandwidth.

Embodiment 6
In the fifth embodiment, the master station device 10 prohibits assignment of the fixed band for a certain period of time to the slave station device 20 to which the fixed band is assigned, so that the other slave station devices do not perform data communication and the slave station device. When 20 performs uplink communication, there occurs a time during which no fixed band is allocated even though there is a space in the fixed band area.
In order to avoid this, as shown in FIG. 16, the slave station management table in the master station apparatus 10 is assigned a priority (133) for each slave station apparatus, and the slave station performs uplink communication. While allocating a fixed band to a device, a fixed band is prevented from being occupied by a specific slave station device.

A process in which the master station device 10 sets priority to the slave station devices 20 to 2n will be described with reference to FIG.
The master station device 10 sets priority 1 for all the slave station devices at the start of connection with the slave station devices 20 to 2n (ST190).
Each time the master station device 10 communicates with the slave station devices 20 to 2n (ST191), the master station device 10 checks whether there is a slave station device to which a fixed band is currently allocated (ST192).
If there is a slave station device to which a fixed bandwidth is allocated, it is checked whether the maximum bandwidth securing time has elapsed since the fixed bandwidth was assigned to the slave station device (ST193). The fixed band allocated to the station apparatus is released (ST194), the number N of all the slave station apparatuses connected to the master station apparatus 10 is set as the priority of the slave station apparatus (ST195), and the fixed band is allocated. 1 is subtracted from the priority (ST198) with respect to the slave station apparatus that has not been assigned.
At this time, nothing is done for the slave station apparatus whose priority is already 1.

FIG. 17 shows an example of how the priority of each slave station device becomes five when a certain slave station device transmits data to the master station device every time communication is performed.
FIG. 18 shows an example of processing in which the master station device 10 allocates a fixed bandwidth in the sixth embodiment.
When receiving a bandwidth securing request from a plurality of slave station devices (ST180), master station device 10 confirms whether there is a vacant area in the fixed bandwidth within the frame (ST181).
If there is a vacancy in the area, the master station device 10 assigns a fixed bandwidth to the requested slave station device with the lowest priority (ST182, ST183) and sets the maximum secured time for the slave station device. A value obtained by dividing a predetermined time (maximum reserved time 100) by priority n is set (ST184).

  As described above, according to the sixth embodiment of the present invention, a specific slave station device does not occupy a fixed bandwidth, and a fixed bandwidth is allocated when there is a slave station device performing uplink communication. Is possible.

Embodiment 7
In the first embodiment, the slave station device 20 gives priority to the bandwidth securing request as shown in FIG. 20, and when the priority of the transmission data is high as shown in FIG. 10 allocates the fixed bandwidth secured by ST10 (ST223).
Further, as shown in FIG. 21, the master station device 10 refers to the priority (ST211) with respect to the bandwidth securing request (ST210) from the slave station device, and only when the priority is higher than the priority specified in advance. A fixed bandwidth is allocated (ST213).

  As described above, when the slave station device performs uplink communication, even when data with high priority and data with low priority are mixed, a fixed bandwidth is allocated only to data with high priority. It is possible to reliably transmit high data without delay.

Claims (8)

A master station device and one to a plurality of slave station devices connected in time division multiple access to the master station device, and a fixed band for transmitting data from the slave station device to the master station device in the master station device And a means for securing a bandwidth in accordance with a transmission request from the slave station device to the master station device, and a transmission bandwidth when performing transmission to the master station in the slave station device. A communication apparatus comprising: means for making a transmission request for allocation; and means for transmitting data to the master station apparatus using the allocated bandwidth. 2. The communication apparatus according to claim 1, further comprising means for releasing a reserved band when there is no data transmission from the slave station apparatus in the master station apparatus for a predetermined time. The master station device includes means for releasing a fixedly secured band for the slave station device after a lapse of a fixed time after the master station device has assigned a bandwidth to the slave station device. The communication device according to claim 1. In the master station device, a fixed bandwidth is not released for the slave station device after a certain period of time has elapsed since the master station device fixedly assigned the bandwidth to the slave station device. The communication apparatus according to claim 2, further comprising means for releasing a fixedly secured band. A slave station device management table is provided in the master station device, and each time the master station device receives a transmission request from the slave station device, the slave station device management table is referred to, and the band allocated for the fixed bandwidth is currently free. In addition to confirming whether there is a fixed bandwidth, if the time since the last release of the fixed bandwidth is shorter than the specified time, the fixed bandwidth is not allocated, and if it is longer than the specified time, the bandwidth is allocated. 5. The communication apparatus according to claim 4, wherein the communication apparatus is managed so as not to occupy a fixedly allocated band by a specific slave station apparatus. The priority for each slave station device is added to the slave station device management table in the master station device, and the master station device is connected to the master station device as the priority of the slave station device when the fixed band for the slave station device is released Means for subtracting 1 from the priority of the other slave station devices and setting a fixed bandwidth to the slave station device having the lowest priority among the slave station devices that have received the transmission request. 6. The communication apparatus according to claim 5, wherein the communication device is set to a value obtained by dividing a predetermined time until allocation of the bandwidth shown in claim 3 by the priority. A priority is added to the transmission request and transmission data from the slave station device, and the master station device refers to the priority in the transmission request from the slave station device, and is fixed only to a higher priority. The communication according to claim 1, further comprising means for allocating a band, wherein the slave station apparatus includes means for transmitting transmission data having a high priority using a transmission band fixedly allocated by the parent station apparatus. apparatus. A communication method using a master station device and a communication device comprising one to a plurality of slave station devices connected in time division multiple access to the master station device, wherein the slave station device to the master station device in the master station device A step of securing and releasing a band for transmitting data to the fixed station, and a step of securing a band fixedly in accordance with a transmission request from the slave station device to the master station device. A communication method comprising: a transmission request for allocating a transmission band when transmitting to a station; and a step of transmitting data to a master station device using the allocated band.

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