JP2009017054A - Communication apparatus and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption and to transmit a large amount of data by changing available time corresponding to the kind of a power source. <P>SOLUTION: When performing radio communication in a group including two or more communication apparatuses, the radio communication part of the own apparatus is controlled to be enabled or to sleep depending on whether the power of the own apparatus is supplied from an external power source or a battery in a band other than the band in which the own apparatus serves as a transmission side or a reception side in communication. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for performing wireless communication in a group formed by a plurality of communication devices.

  Conventionally, in a communication system that consists of a central control station and a terminal station under the control of the central control station and performs time division multiplexing, communication allocated per frame of the terminal station by a polling signal transmitted by the central control station Possible time is determined.

  In such a time-division communication method, since the terminal station normally communicates only in the time allocated to the own station, communication is performed for power saving except for the time allocated to the own station and the time for receiving the polling signal. Part can be put into a sleep state.

  Here, in the PCM communication in IEEE802.11, both the time allocated for bandwidth and the time for contention access are defined. In this case, the terminal station needs to be able to communicate for the polling time and the contention access time in addition to the bandwidth allocated to the terminal station.

  In recent years, high-speed wireless personal area network (WPAN) has been standardized, such as IEEE802.15.3 and WiMedia. Also in these standards, the time for bandwidth allocation and the contention access time are defined.

In recent years, electronic devices with high portability handle large-capacity data such as image data such as digital cameras and PDAs, and the power source is driven by a battery instead of an AC power source. In wireless devices mounted on these devices, both large-capacity communication and power saving are desired.
IEEE802.15.3 MAC WiMedia MAC

  However, the above conventional technique requires a wide band (communication time) in order to perform large-capacity transmission, and there is a trade-off that the power of the communication unit should be turned off as much as possible to save power.

  An object of the present invention is to enable reduction of power consumption and large-capacity communication by changing a communicable time according to the type of power supply.

  The present invention is a communication device that performs wireless communication in a group formed by a plurality of communication devices, the detection means for detecting whether the power supply of the device is an external power supply or a battery, and the device as a transmission side or a reception side Control means for controlling the wireless communication means of its own device to a communicable state or a sleep state in accordance with the result detected by the detecting means, other than the band in which communication is performed.

  Further, the present invention is a communication method executed by a communication device that performs wireless communication in a group formed by a plurality of communication devices, the detection step of detecting whether the power supply of the device is an external power supply or a battery, A control step of controlling the wireless communication means of the device to a communicable state or a sleep state according to a result detected in the detection step other than a band in which the device communicates as a transmission side or a reception side. Features.

  According to the present invention, by changing the communicable time according to the type of power supply, it is possible to make a trade-off between reducing power consumption and increasing communication capacity in wireless communication.

  The best mode for carrying out the invention will be described below in detail with reference to the drawings. In the present embodiment, a case where a master transmits a beacon in a group formed by a plurality of communication devices (wireless stations) and a network is configured by a plurality of slaves that receive the beacon will be described as an example. .

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of a wireless group in the first embodiment. In FIG. 1, 101 to 104 are wireless stations communicating with the same wireless group 10, wireless stations 101 and 102 are driven by an external power source, and wireless stations 103 and 104 are driven by a battery. Reference numeral 111 denotes a wireless station communicating with the wireless group 20, and the beacon of the wireless station 111 is intercepted by the wireless station 103.

  In the example illustrated in FIG. 1, the wireless station 101 transmits a beacon to the wireless stations 102 to 104, forms one wireless group 10, and the wireless station 103 intercepts a beacon transmitted by the wireless station 111 that forms the wireless group 20. It is in a state of being.

  FIG. 2 is a diagram illustrating an example of a basic configuration of a radio station according to the first embodiment. In FIG. 2, reference numeral 201 denotes a control unit that controls the radio station in accordance with a program and control data stored in a ROM described later. A ROM 202 stores a program, control data, and the like of the control unit 201. Reference numeral 203 denotes a RAM as a temporary storage area including a work area and a table used by the control unit 201 when executing processing.

  A wireless communication unit 204 performs wireless communication such as IEEE802.15.3 or WiMedia. The wireless communication unit 204 is controlled by the control unit 201 to be in a communicable state or a sleep state depending on whether the power source is an external power source or a battery. This control will be further described in detail.

  Reference numeral 205 denotes a power supply detection unit that detects the type of power supply. Reference numeral 206 denotes a power supply unit such as an external power supply or a battery. Here, the power supply detection unit 205 detects whether the power supply unit 206 is connected to an external power supply or a battery. The detection method may be a known method, and a detailed description thereof is omitted here.

  FIG. 3 is a diagram illustrating a band arrangement and a communication state of each wireless station in the first embodiment. In the upper band shown in FIG. 3, the arrow (↓) in the square indicating the reservation status of each radio station indicates that the upper side is the transmitting side and the lower side is the receiving side. 100 and 100 'are beacon bands. 200 is an Alien BP DRP band reserved for the wireless station 103 to intercept the beacon of the wireless station 111 and protect the beacon band of the wireless group 20. Reference numeral 300 denotes a contention access band for acquiring a right for a plurality of wireless stations to access a communication line (channel).

  Here, BP is an abbreviation for Beacon Period, and DRP is an abbreviation for Distributed Reservation Protocol. In addition, “H”, “S”, and “A” above the square indicating the reserved bandwidth for reserving a channel used for communication by each wireless station indicate the type of reservation. “H” is a Hard DRP, which is a band in which a transmitting station determines a receiving station and performs communication. “S” is Soft DRP, which allows contention access, but the transmitting station acquires the right to access without using the back-off time. “A” is Alien BP DRP.

  Although not shown in FIG. 3, there is also a private DRP as a reservation type. This Private DRP can be freely determined by the participating transmitting station and receiving station in this band, such as a channel access method.

  Also, the lower side of the band shown in FIG. 3 indicates whether the wireless stations 101 to 104 are in a communicable state or a sleep state. When the wireless stations 101 to 104 are Wake Up, that is, when communication is possible, the thick line is “up”, and when the wireless stations are in the sleep state, the thick line is “down”. “Owner” indicates a transmission band reserved by the own station, and “Target” indicates a reception band of the own station. “H” indicates a Hard DRP reserved by other wireless stations as receiving stations other than the own station, and “s” indicates a Soft DRP reserved by other wireless stations as receiving stations other than the own station.

  In WiMedia, the receiving station performs non-contention access communication determined by the Hard DRP band and the Private DRP band reserved by the transmitting station. However, when there is no data or the amount of data is small despite the reserved bandwidth, the transmitting station releases the remaining bandwidth with a signal called UDA. On the other hand, when the receiving station returns a signal called UDR, all the radio stations in the radio group can communicate with each other by using contention access in the remaining band.

  In WiMedia, a transmitting station designates a receiving station and reserves a band in the Soft DRP band reserved by the transmitting station, but basically it is a contention access period. Since the transmitting station does not follow the random back-off procedure in this band, the band can be secured more advantageously than other radio stations. However, when there is no data to be transmitted to the transmitting station or when the amount of data is small, the remaining bandwidth becomes a contention access period by wireless stations in the same wireless group.

  Here, when the wireless stations 101 and 102 are connected to an external power source, it is not very important to reduce power consumption. On the other hand, when a large amount of data is to be transmitted / received, securing a larger bandwidth is an important item.

  On the other hand, when the wireless stations 103 and 104 are driven by batteries, it may be important to transmit and receive large amounts of data, but power saving is prioritized.

Therefore, as shown in FIG. 3, the radio stations 101 and 102 connected to the external power source are allowed to communicate in all bands other than Alien BP DRP. Thereby, communication in the following time zone becomes possible.
1. Time zone for transmitting and receiving beacons 2. Band reserved for transmission by own station 3. Band reserved for other radio stations in same radio group 10 by setting own station as receiving station 4. Competing access time 5. Time after the receiving station transmits UDR in the Hard DRP band reserved by other wireless stations in the same wireless group 10 as receiving stations other than the own station 6. Other wireless stations in the same wireless group 10 When the transmitting station does not transmit data in the Soft DRP band reserved as a receiving station other than its own station or the remaining time when the communication ends early with less data, on the other hand, in the battery-powered radio stations 103 and 104, Bands reserved by other wireless stations in the same wireless group 10 as receiving stations other than the local station suppress power consumption without performing communication in the sleep state. However, in the Alien BP DRP band 200 reserved by the wireless station 103 by the beacon of the wireless station 111 of the other wireless group 20 detected by the wireless station 103, the wireless station 103 is not put in the sleep state in order to maintain the reservation.

  According to the first embodiment, power consumption in wireless communication is detected by detecting whether the wireless station is connected to an external power source or being driven by a battery, and changing the communicable time according to the detected result. Can be traded off and the capacity of communication can be increased.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described in detail with reference to the drawings. The configuration of the wireless group and the configuration of the wireless station in the second embodiment are the same as those in the first embodiment (FIGS. 1 and 2), and a description thereof is omitted here.

  FIG. 4 is a diagram illustrating a band arrangement and a communication state of each wireless station in the second embodiment. Here, the radio stations 101 to 104 shown in FIG. 4 perform communication similar to that of the first embodiment shown in FIG.

  In the second embodiment, the wireless stations 101 and 102 connected to the external power supply sleep in the Hard DRP band reserved by other wireless stations as receiving stations other than the own station, that is, the band indicated by “h”. Transition to the state. In FIG. 4, the wireless station 102 is in a sleep state in a band indicated by “h”. The battery-driven radio stations H1 and H2 perform the same control as in the first embodiment. When such control is performed, only a radio station that reserves a band in the Hard DRP band and a radio station set as a receiving station can communicate. In the example shown in FIG. 4, the wireless station 101 is a transmitting station and the wireless station 103 is a receiving station. In this way, when there is one receiving station, the transmitting station transmits UDA, and after the receiving station transmits UDR, if the receiving station has data addressed to the transmitting station, data can be transmitted immediately. become.

  The Alien BP DRP 200 and the contention access bandwidth 300 are the same as those in the first embodiment.

  In the example shown in FIG. 4, only Hard DRP has been described as the reserved bandwidth, but the same applies to the case of Private DRP.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described in detail with reference to the drawings. The configuration of the wireless group and the configuration of the wireless station in the third embodiment are the same as those in the first embodiment (FIGS. 1 and 2), and description thereof is omitted here.

  FIG. 5 is a diagram illustrating a band arrangement and a communication state of each wireless station in the third embodiment. Here, the radio stations 101 to 104 shown in FIG. 5 perform the same communication as in the first embodiment shown in FIG.

  In the third embodiment, the battery-powered radio stations 103 and 104 enter a sleep state in the Hard DRP band reserved by other radio stations as a receiving station other than its own station, that is, a band indicated by “h”. Unlike the first embodiment, the battery-powered radio stations 103 and 104 do not enter the sleep state in the Soft DRP band reserved by other radio stations as a receiving station other than the own station, that is, the “s” band. In this way, even if it is a battery-powered radio station, there is a high need for data communication rather than power saving by not going to sleep during the Soft DRP period when there is a high possibility of data communication. It can respond flexibly.

  In the example shown in FIG. 5, only Hard DRP is described as the reserved bandwidth, but the same applies to Private DRP.

[Fourth Embodiment]
Next, a fourth embodiment according to the present invention will be described in detail with reference to the drawings. The configuration of the wireless group and the configuration of the wireless station in the fourth embodiment are the same as those in the first embodiment (FIGS. 1 and 2), and description thereof is omitted here.

  FIG. 6 is a diagram illustrating a band arrangement and a communication state of each wireless station in the fourth embodiment. Here, the radio stations 101 to 104 shown in FIG. 6 perform the same communication as that of the first embodiment shown in FIG.

  In the fourth embodiment, a radio station without parentheses as a receiving station within a square indicating the reserved bandwidth of each radio station is a radio station that the transmitting station originally intends to transmit data. A radio station with parentheses is a radio station added as a receiving station. As described above, in the fourth embodiment, the wireless stations 101 and 102 connected to the external power source are set as receiving stations even in bands where other wireless stations are reserved as receiving stations, and communication is possible in those bands. It becomes a state.

  That is, as shown in FIG. 6, the wireless stations 101 and 102 are in a communicable state in a very large band. This is because the wireless stations 101 and 102 of the external power source are communicable after the bandwidth is released because the wireless stations other than the local station are reserved as receiving stations even in the band of the original receiving station. is there.

  In addition, since the wireless stations 101 and 102 of the external power supply are reserved as receiving stations even in the band of the original receiving station, the wireless stations other than the own station can perform communication by competitive access.

  In addition, the battery-powered radio station can communicate only with the band reserved by itself and the band designated as the receiving station and the competitive access band 300, and enters a sleep state in other bands, so that power consumption can be reduced. .

[Fifth Embodiment]
Next, a fifth embodiment according to the present invention will be described in detail with reference to the drawings. The configuration of the wireless group and the configuration of the wireless station in the fifth embodiment are the same as those in the first embodiment (FIGS. 1 and 2), and a description thereof is omitted here.

  FIG. 7 is a diagram illustrating a band arrangement and a communication state of each wireless station in the fifth embodiment. Here, the radio stations 101 to 104 shown in FIG. 7 perform the same communication as that of the first embodiment shown in FIG.

  In the fifth embodiment, a wireless station without parentheses as a receiving station within a square indicating the reserved bandwidth of each wireless station is a wireless station that the transmitting station originally intends to transmit data. A radio station with parentheses is a radio station added as a receiving station. As described above, in the fifth embodiment, the wireless stations 101 and 102 connected to the external power source are also set as receiving stations in the Soft DRP band in which other wireless stations are reserved as receiving stations. Communication is possible in the band.

  In addition, the wireless stations 101 and 102 connected to the external power supply shift to the sleep state in the Hard DRP band reserved by other wireless stations as a receiving station other than the own station, that is, the band indicated by “h”. When such control is performed, only a radio station reserved as a band in the Hard DRP band and a radio station set as a receiving station can communicate. In particular, when there is one receiving station, after the transmitting station transmits UDA and the receiving station transmits UDR, if the receiving station has data addressed to the transmitting station, data transmission can be performed immediately. .

  The Alien BP DRP 200 and the contention access band 300 are the same as in the fourth embodiment.

  In the example shown in FIG. 7, only Hard DRP is described as the reserved bandwidth, but the same applies to the case of Private DRP.

[Sixth Embodiment]
Next, a sixth embodiment according to the present invention will be described in detail with reference to the drawings. The configuration of the wireless group and the configuration of the wireless station in the sixth embodiment are the same as those in the first embodiment (FIGS. 1 and 2), and description thereof is omitted here.

  FIG. 8 is a diagram illustrating a band arrangement and a communication state of each wireless station in the sixth embodiment. Here, the radio stations 101 to 104 shown in FIG. 8 perform communication similar to that of the first embodiment shown in FIG.

  In the sixth embodiment, a radio station without parentheses as a receiving station within a square indicating a reserved bandwidth of each radio station is a radio station that the transmitting station originally intends to transmit data. A radio station with parentheses is a radio station added as a receiving station so that it can communicate when it becomes accessible in a designated band.

  As shown in FIG. 8, the battery-powered radio stations 103 and 104 enter a sleep state in a Hard DRP band that is not reserved as a band to be transmitted / received by the own station, that is, a band indicated by “h”. In this band, all the radio stations 101 to 104 can communicate.

  In the example shown in FIG. 8, only Hard DRP is described as the reserved bandwidth, but the same applies to the case of Private DRP.

  In the embodiment described above, the trade-off between the reduction in power consumption and the increase in communication capacity can be handled according to the priority of each radio station by changing the communicable time depending on the type of power supply. Moreover, although the example which changes the time which can communicate uniformly according to the power supply type was shown, you may change the time which can communicate individually according to the priority of each radio station.

  Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it is applied to an apparatus (for example, a copier, a facsimile machine, etc.) composed of a single device. It may be applied.

  In addition, a recording medium in which a program code of software for realizing the functions of the above-described embodiments is recorded is supplied to the system or apparatus, and the computer (CPU or MPU) of the system or apparatus stores the program code stored in the recording medium. Read and execute. It goes without saying that the object of the present invention can also be achieved by this.

  In this case, the program code itself read from the computer-readable recording medium realizes the functions of the above-described embodiments, and the recording medium storing the program code constitutes the present invention.

  As a recording medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  In addition, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the following cases are included. That is, based on the instruction of the program code, an OS (operating system) running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing. .

  Further, the program code read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. After that, based on the instruction of the program code, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing. Needless to say.

It is a figure which shows the structure of the radio | wireless group in 1st Embodiment. It is a figure which shows an example of the fundamental structure of the radio station in 1st Embodiment. It is a figure which shows the band arrangement | positioning and communication state of each radio station in 1st Embodiment. It is a figure which shows the band arrangement | positioning and communication state of each radio station in 2nd Embodiment. It is a figure which shows the band arrangement | positioning and communication state of each radio station in 3rd Embodiment. It is a figure which shows the band arrangement | positioning and communication state of each radio station in 4th Embodiment. It is a figure which shows the band arrangement | positioning and communication state of each radio station in 5th Embodiment. It is a figure which shows the band arrangement | positioning and communication state of each radio station in 6th Embodiment.

Explanation of symbols

10 radio group 20 radio group 101 radio station 102 radio station 103 radio station 104 radio station 111 radio station 201 control unit 202 ROM
203 RAM
204 Wireless communication unit 205 Power supply detection unit 206 Power supply unit

Claims (8)

A communication device that performs wireless communication in a group formed by a plurality of communication devices,
Detection means for detecting whether the power supply of the device is an external power supply or a battery;
Control means for controlling the wireless communication means of the own apparatus to a communicable state or a sleep state according to the result detected by the detecting means other than the band in which the own apparatus communicates as the transmitting side or the receiving side. A communication device.   The control means controls the wireless communication means of the own apparatus to a communicable state when the power supply of the own apparatus is an external power supply, and to a sleep state when the power supply is a battery. The communication apparatus according to 1.   The control means controls the wireless communication means of the own apparatus to a sleep state when the power supply of the own apparatus is an external power supply and in a band where communication is permitted by permitting competing access of another communication apparatus. The communication device according to claim 1.   The control means controls the wireless communication means of the own device to be in a communicable state when the power supply of the own device is a battery and in a band where communication is permitted by permitting competing access of another communication device. The communication device according to claim 1.   5. The communication apparatus according to claim 1, further comprising a setting unit configured to perform communication with the own apparatus as a receiving side when the power supply is an external power supply. A communication method executed by a communication device that performs wireless communication in a group formed by a plurality of communication devices,
A detection process for detecting whether the power supply of the device is an external power supply or a battery;
A control step of controlling the wireless communication means of the device to a communicable state or a sleep state according to a result detected in the detection step other than a band in which the device communicates as a transmission side or a reception side. A characteristic communication method.   A program for causing a computer to execute the communication method according to claim 6.   A computer-readable recording medium on which the program according to claim 7 is recorded.

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