JP4862418B2 - Wireless communication apparatus and wireless communication system - Google Patents

Wireless communication apparatus and wireless communication system Download PDF

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JP4862418B2
JP4862418B2 JP2006032055A JP2006032055A JP4862418B2 JP 4862418 B2 JP4862418 B2 JP 4862418B2 JP 2006032055 A JP2006032055 A JP 2006032055A JP 2006032055 A JP2006032055 A JP 2006032055A JP 4862418 B2 JP4862418 B2 JP 4862418B2
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beacon
wireless communication
beacon frame
communication device
hibernation
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JP2007214842A (en
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茂 菅谷
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ソニー株式会社
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02DCLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THIR OWN ENERGY USE
    • Y02D70/00Techniques for reducing energy consumption in wireless communication networks
    • Y02D70/20Techniques for reducing energy consumption in wireless communication networks independent of Radio Access Technologies

Description

  The present invention relates to a wireless communication device and a wireless communication system, and more particularly to a wireless communication device and a wireless communication system that form an autonomous distributed ad hoc network with surrounding wireless communication devices.

  A wireless communication system that forms a self-distributed ad hoc network with surrounding wireless communication devices has been proposed as WiMedia MBOA Distributed MAC. In this wireless communication system, a wireless communication device to be activated first sets a superframe period at a predetermined period, and further sets a predetermined beacon period including a plurality of beacon slots in front of the superframe, Is a system that periodically transmits. Further, the wireless communication device that is activated thereafter is configured to transmit a beacon in an empty beacon slot within the above-described beacon period. Thus, all the wireless communication devices transmit beacon signals at predetermined positions, thereby performing wireless data communication while grasping the behavior of wireless communication devices existing in the vicinity.

  In the conventional beacon signal exchange method, one beacon slot is fixedly assigned to a specific wireless communication device. Therefore, a beacon slot in which a beacon is not transmitted is also assigned to a wireless communication device in a sleep operation. It was.

  A hibernation mode is defined as a sleep operation in the same system. In the hibernation mode, a method for notifying that a beacon is transmitted only in a predetermined cycle is defined in information exchanged in advance with a beacon. By this method, a wireless communication device without transmission demand can perform a sleep operation over a plurality of superframe periods, and can suppress power consumption of the wireless communication device.

  Further, for the purpose of providing a communication system capable of increasing power saving, there is a technique disclosed in Japanese Patent Laid-Open No. 2005-269230. In the technique disclosed in this document, a plurality of stations in a wireless network are grouped, beacon reception timing is set for each group, and at least two or more groups have different beacon reception timings. A plurality of data packets transmitted from a point to each station are dispersed in time.

JP 2005-269230 A

  By the way, one beacon slot is always assigned to one wireless communication device. This assignment does not depend on the operation mode of each wireless communication device. For example, the beacon slot is uniformly assigned to the wireless communication device in the hibernation mode. However, a wireless communication device operating in the hibernation mode has no meaning even if traffic information such as time slot information that can be used by the wireless communication device is described unless transmission demand is generated. In other words, a terminal in hibernation mode does not need to broadcast redundant traffic information, and it is sufficient to distribute information indicating its existence, and a beacon slot is uniformly distributed to terminals in hibernation mode. Allocating will lead to waste of limited resources.

  Further, in the configuration of the above Japanese Patent Application Laid-Open No. 2005-269230, unless the access points are grouped in advance, the reception timing is not dispersed, and communication cannot be performed without intervening access points. Further, unless the access point always emits a beacon, the reception timing of the communication terminal cannot be distributed, and the power consumption of the access point is not reduced. For this reason, when applied to an ad hoc network, it is necessary for all wireless communication apparatuses to transmit beacons fairly, and it is necessary to solve a configuration problem that processing of a specific wireless communication apparatus increases.

  The present invention has been made in view of the above-described problems of conventional wireless communication technologies, and the object of the present invention is that the number of beacon slots is insufficient even when a large number of wireless communication devices exist in the same space. New and improved wireless communication that can avoid the decrease that occurs and that can simplify the processing of wireless communication devices operating in hibernation mode and achieve low power consumption operation. An apparatus and a wireless communication system are provided.

  In order to solve the above-described problem, according to a first aspect of the present invention, in an ad hoc network radio communication apparatus that transmits and receives beacon frames at a predetermined cycle, a first including fixed-length data and variable-length data including reservation information. A first beacon frame generator (for example, a normal beacon generator 107 described later) that generates one beacon frame, and a second beacon frame that excludes the reservation information from the first beacon frame And a beacon frame generation unit (for example, a shortened beacon generation unit 109 to be described later), and the first and second beacon frames are switched and transmitted.

  For example, the second beacon frame generation unit can generate the second beacon frame when data transmission / reception is not performed.

  According to such a configuration, when there is no demand for data communication, it is possible to shorten the beacon frame configuration and to speed up the reception process by not describing reservation information or the like. That is, the reservation status can be optimized by not describing the reservation information in the beacon of the wireless communication device that does not perform data communication. In addition, it is not necessary to inadvertently propagate farther reservation information of a wireless communication device not directly related to data communication, so that the minimum necessary reservation setting is possible and the transmission path utilization efficiency is improved. . Further, since the operation of updating available slots, which has been conventionally performed based on the reservation parameter information described in the beacons of surrounding wireless communication devices, can be omitted, the processing of the wireless communication device can be simplified. Play.

  Further, for example, the second beacon frame generation unit can generate the second beacon frame when a hibernation mode for performing a temporary sleep operation is set.

  According to this configuration, it is possible to simplify unnecessary information collection during the sleep operation by simplifying the beacon of the wireless communication device in the hibernation mode that performs the sleep operation. In other words, the beacon of a wireless communication device operating in hibernation mode is composed only of simple information that does not add redundant traffic information, and only the existence of itself can be notified, so that simple processing can be completed. . Also, it is possible to save the trouble of notifying reservation information that is originally unnecessary. In this case, it is possible to perform simple processing such as using hardware configured with a simple circuit during the sleep operation, and low power consumption operation is possible.

  The first beacon frame generation unit can generate the first beacon frame, for example, when the hibernation mode is changed to the normal operation mode.

  According to such a configuration, the beacon in the normal operation mode notifies the reservation information and the like, so that it is necessary to exchange reservation information with surrounding wireless communication devices during data transmission or the like. When is in an active state, there is an effect that advanced calculation processing can be performed.

  In addition, another wireless communication device of the present invention includes a first beacon frame generation unit (for example, a normal beacon generation unit described later) that generates a first beacon frame including fixed length data and variable length data including reservation information. 107), a second beacon frame generation unit (for example, a shortened beacon generation unit 109 to be described later) that generates a second beacon frame obtained by removing the reservation information from the first beacon frame, and the first beacon A third beacon frame generation unit (for example, a shortened beacon generation unit 109 to be described later) that generates a third beacon frame obtained by removing the variable length data from the frame, and the first to third beacon frames It is characterized by switching and transmitting.

  In the same manner as described above, for example, the second beacon frame generation unit can generate the second beacon frame when data transmission / reception is not performed. Further, for example, the second beacon frame generation unit can generate the second beacon frame when a hibernation mode for performing a temporary sleep operation is set. The first beacon frame generation unit can generate the first beacon frame, for example, when the hibernation mode is changed to the normal operation mode.

  According to such a configuration, it is possible to switch and transmit a third beacon slot that is simpler than the second beacon slot. In this way, even if there are a large number of wireless communication devices in the same space, it is possible to more effectively avoid the decrease in the number of beacon slots, and to operate in hibernation mode. It is possible to simplify the processing of the existing wireless communication device and realize low power consumption operation.

  In order to solve the above problems, according to a second aspect of the present invention, there is provided a wireless communication system in which an ad hoc network is formed by a plurality of wireless communication devices that transmit and receive beacon frames at a predetermined period. The wireless communication apparatus of the present invention is a wireless communication apparatus that operates in a hibernation mode in which a temporary sleep operation is performed when each wireless communication apparatus transmits and receives beacon frames using a predetermined beacon slot to manage an ad hoc network. Defines one beacon slot used for transmission / reception of a beacon frame, and shares the one beacon slot with other wireless communication devices.

  According to such a wireless communication system, it is possible to easily grasp the presence of all the wireless communication devices in the hibernation mode only by receiving the same beacon slot in the surrounding wireless communication devices. In addition, by sharing the beacon slot of the wireless communication device in the hibernation mode, it is possible to compensate for the shortage of the absolute number of beacon slots.

  In the wireless communication device, a normal beacon slot can be used when the hibernation mode is changed to the normal operation mode. That is, when transitioning from the hibernation mode to the normal operation mode, it is possible to use beacon slots that are different from those of other wireless communication devices so as not to compete with other wireless communication devices.

  The shared beacon slot may be defined in advance as a wireless communication protocol (specification), but may be defined when the ad hoc network is constructed. In the ad hoc network, it may be defined by a wireless communication device that first transits to the hibernation mode when there is no wireless communication device that operates in the hibernation mode. Alternatively, a wireless communication device that is about to transition to hibernation mode can exchange information with another wireless communication device that is already operating in hibernation mode, thereby defining a shared beacon slot. Also good.

  In order to solve the above problems, according to a third aspect of the present invention, there is provided a wireless communication system in which an ad hoc network is formed by a plurality of wireless communication devices that transmit and receive beacon frames at a predetermined cycle. The radio communication system according to the present invention sets a hibernation operation cycle that is an integral multiple of a predetermined superframe as a hibernation mode for performing a temporary sleep operation, and is active in each radio communication device that operates in the hibernation mode. The frame is defined as an offset value (hibernation offset).

  According to such a configuration, when a beacon slot of a wireless communication device operating in the hibernation mode is activated at a timing in which the same slot has a different offset value for each superframe and enters an active operation mode, By transmitting a beacon in a normal beacon slot, it is possible to solve the shortage of the number of beacon slots.

  Further, for example, each wireless communication device can transmit a beacon frame using the same beacon slot.

  Each wireless communication device in hibernation mode can use one beacon slot in a time-sharing manner by using an offset superframe, thereby obtaining an effect of compensating for the shortage of beacon slots. As described above, by sharing the beacon slots of the wireless communication devices in the hibernation mode, it is possible to compensate for the shortage of the absolute number of beacon slots.

  The hibernation operation cycle can be set according to the number of wireless communication devices constituting the ad hoc network. For example, when an ad hoc network is configured by eight wireless communication apparatuses, the hibernation operation cycle can be set as eight times (or nine times or more) the superframe.

  In order to solve the above-described problem, according to a fourth aspect of the present invention, there is provided a wireless communication device that forms an autonomous distributed network by a plurality of wireless communication devices that transmit and receive beacon frames at a predetermined cycle, A communication control unit that controls transmission / reception of data while transitioning between a plurality of modes including an operation mode in which data is transmitted / received in a state and a hibernation mode in which a temporary sleep operation is performed, wherein the communication control unit includes the hibernation A wireless communication apparatus is characterized in that, under a mode, a hibernation operation cycle that is an integral multiple of a predetermined superframe is set, and an active period is determined based on an offset value indicating an active superframe. Provided.

  According to another aspect of the present invention, there are provided a program for causing a computer to function as the wireless communication apparatus of the present invention, and a computer-readable recording medium on which the program is recorded. Here, the program may be described in any programming language. In addition, as a recording medium, for example, a recording medium that is currently used as a recording medium capable of recording a program, such as a CD-ROM, a DVD-ROM, or a flexible disk, or any recording medium that is used in the future should be adopted. Can do.

  As described above, according to the present invention, even when a large number of wireless communication devices exist in the same space, it is possible to avoid a decrease in the number of beacon slots being insufficient, and in hibernation mode. It is possible to simplify the processing of the operating wireless communication device and realize low power consumption operation. Other effects of the present invention will be described in detail in the best mode for carrying out the invention described below.

  Exemplary embodiments of a wireless communication apparatus and a wireless communication system according to the present invention will be described below in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  Here, functions realized in the communication system according to the present embodiment will be briefly described. First, it is assumed that a beacon slot is assigned uniformly regardless of the operation mode of a wireless communication device (for example, FIGS. 1 and 111). In this case, one beacon slot is also assigned to the wireless communication device in the hibernation mode, but actually, the wireless communication device transmits a beacon signal in all the beacon slots assigned to itself. As a result, a beacon slot in which no signal is transmitted is generated, and communication resources are wasted. This phenomenon is not a major problem while the number of wireless communication terminals in hibernation mode is small, but it is inevitably in the hibernation mode when the number of wireless communication terminals participating in the ad hoc network is large. The number of terminals also increases, and as a result, the waste of communication resources becomes obvious.

  In the present embodiment, the following method is adopted from the viewpoint of preventing such waste of resources.

  First, several beacon slots within the beacon period are assigned exclusively to wireless communication devices under the hibernation mode, and the number of beacon slots is fixed or variable regardless of the number of wireless communication devices under the hibernation mode. Then, the beacon slot for the hibernation mode is shared among all the wireless communication devices under the hibernation mode. By adopting such a method, even when the number of wireless communication terminals in hibernation mode increases, it is possible to prevent many beacon slots from being wasted and to waste communication resources. It can be effectively prevented. The number of beacon slots for the hibernation mode is arbitrary, and may be one slot or a plurality of slots. In addition, it is arbitrary as to which slot is allocated within the beacon period. Furthermore, when there is no terminal in the hibernation mode, this beacon slot is allocated to the wireless communication apparatus in the normal operation mode. You may do it.

  On the other hand, when the sharing method of the dedicated beacon slot is adopted, one problem arises. That is, if multiple wireless communication devices shift to hibernation mode at the same time, multiple wireless communication devices become active simultaneously in the beacon slot dedicated to this hibernation mode, and a beacon signal collision may occur. That's what it means. Such collision of beacon signals has a low probability of occurrence when the number of wireless communication apparatuses in the hibernation mode is small, and it is not necessary to take a special method for avoiding the collision.

  However, if the number of wireless communication devices in hibernation mode increases to several tens, etc., the collision probability inevitably increases, so it is desirable to take some measures. More specifically, each wireless communication device in hibernation mode should take measures to transmit a beacon signal at a timing when other wireless communication terminals do not use a beacon slot dedicated to hibernation mode. Is desirable.

  Various methods can be considered as a method for preventing such a collision. In the present embodiment, the following method is particularly adopted.

  First, a superframe group composed of a plurality of superframes (that is, an integral multiple of a superframe) is assumed as one period (hereinafter, this period is referred to as a “hibernation period”). If the wireless communication apparatuses under the hibernation mode transmit beacon signals in different superframes included in the superframe group, beacon signals can be prevented from colliding in the hibernation mode beacon slot. .

  In order to realize such a transmission method, in the communication system according to the present embodiment, as an offset value, which radio communication device transmits a beacon signal at what frame from the first super frame of the super frame group. Define in advance. If the offset value is defined in this way, on the basis of this offset value and the hibernation period, in what superframe of the superframe group it is necessary to transit to the active state and transmit a beacon signal. Each wireless communication device can grasp it.

  In addition, in the hibernation mode, there is little information that needs to be notified to surrounding wireless communication devices using beacon information. Accordingly, the amount of information contained in the beacon signal is reduced and the frame length of the beacon frame is shortened. However, this point will be described in detail later.

  Hereinafter, a specific configuration and operation of the present embodiment for realizing the above functions will be described.

(1) Configuration example of wireless ad hoc network (Fig. 1)
FIG. 1 shows a configuration example of a wireless ad hoc network based on autonomous distributed control.

  The wireless communication device # 1 (111) can communicate with the wireless communication device # 2 (112) in the radio wave reachable range 121. The wireless communication device # 2 (112) can communicate with the wireless communication devices # 1 (111), # 3 (113), and # 4 (114) within the radio wave reachable range 122. The wireless communication device # 3 (113) can communicate with the wireless communication devices # 2 (112), # 7 (117), and # 8 (118) within the radio wave reachable range 123. The wireless communication device # 4 (114) can communicate with the wireless communication devices # 2 (112) and # 5 (115) within the radio wave reachable range 124. The wireless communication device # 5 (115) can communicate with the wireless communication devices # 4 (114), # 6 (116), and # 7 (117) in the radio wave reachable range 125. The wireless communication device # 6 (116) can communicate with the wireless communication devices # 5 (115) and # 7 (117) within the radio wave reachable range 126. The wireless communication device # 7 (117) can communicate with the wireless communication devices # 3 (113), # 5 (115), # 6 (116), and # 8 (118) within the radio wave reachable range 127. . The wireless communication device # 8 (118) can communicate with the wireless communication devices # 3 (113) and # 7 (117) within the radio wave reachable range 128.

(2) Super frame configuration example (Fig. 2)
FIG. 2 shows a superframe configuration example. FIG. 2 shows a state in which a superframe period is defined at a predetermined time and is further subdivided into 256 media access slots (MAS) from MAS-0 to MAS-255. In the superframe, a beacon period as a management area and a data transmission area are arranged.

  During the beacon period, beacon slots are set at predetermined intervals, and parameters are exchanged with surrounding wireless communication devices using a unique beacon slot for each wireless communication device. The required length of the beacon period is determined depending on the number of wireless communication apparatuses existing around the beacon period. In the present embodiment, a total of 12 beacon slots from beacon slots BS0 to BS11 are prepared using media access slots MAS-0 to MAS-3.

(3) Beacon slot usage setting example (Fig. 3)
FIG. 3 shows an example of usage settings for beacon slots. Here, the result of selecting the beacon slot used by each wireless communication device that constitutes one network group by notifying the beacon slot that is not used with the surrounding wireless communication device is shown. ing.

  In the example shown in FIG. 3, the wireless communication device # 1 transmits its beacon (beacon is indicated by “B” in the figure. The same applies hereinafter) in the beacon slot 3 (BS3). # 2 transmits its own beacon in beacon slot 8 (BS8), wireless communication device # 3 transmits its beacon in beacon slot 6 (BS6), and wireless communication device # 4 transmits in its beacon slot 2 (BS2). Wireless communication device # 5 transmits its own beacon in beacon slot 4 (BS4), wireless communication device # 6 transmits its own beacon in beacon slot 9 (BS9), and wireless communication device # 5 # 7 transmits its own beacon in beacon slot 5 (BS5), and wireless communication apparatus # 8 transmits its beacon in beacon slot 7 (BS7).

  Furthermore, beacon slot 0 (BS0), beacon slot 1 (BS1), beacon slot 10 (BS10), and beacon slot 11 (BS11) are reserved for the use of wireless communication devices newly entering this network. It is the composition which becomes.

(4) Hibernation mode operation example (Fig. 4)
FIG. 4 shows an example of operation in the conventional hibernation mode.
FIG. 4 shows a method in which a superframe for performing a hibernation operation is defined after an active superframe period and is activated again in an active superframe period. As shown in FIG. 4, a beacon is transmitted in an active superframe period, and a beacon is not transmitted in a superframe that performs a hibernation operation.

(5) Hibernation offset setting (Figure 5)
FIG. 5 is a diagram showing the setting of the hibernation offset according to the present embodiment.
Here, 8 superframes are set as the hibernation cycle, and each wireless communication apparatus is configured to set the hibernation mode according to this cycle.

  As shown in FIG. 5, in superframe-0, the wireless communication apparatus with hibernation offset = 0 becomes active and transmits a beacon. Similarly, the radio communication apparatus with hibernation offset = 1 becomes active in superframe-1. In superframe-2, the wireless communication apparatus with hibernation offset = 2 is active. In superframe-3, the wireless communication apparatus with hibernation offset = 3 becomes active. In the superframe-4, the wireless communication apparatus with the hibernation offset = 4 becomes active. In the super frame-5, the wireless communication apparatus with the hibernation offset = 5 becomes active. In the superframe-6, the wireless communication device with the hibernation offset = 6 becomes active. In the superframe-7, the wireless communication device with the hibernation offset = 7 becomes active.

  Thereafter, when the hibernation period expires, the process returns to superframe-0 and a series of operations are repeated.

  In the present embodiment, there will be described a case where the number of wireless communication apparatuses that construct an ad hoc network is eight, and eight superframes are set as the hibernation period, but the present invention is not limited to this. If it is assumed that a different hibernation offset is set in each wireless communication device, the hibernation cycle can be set according to the number of wireless communication devices. For example, the number of superframes equal to or exceeding the number of wireless communication devices can be set as the hibernation cycle.

(6) Configuration example of normal beacon frame (FIG. 6)
FIG. 6 shows a configuration example of a normal beacon frame. This normal beacon frame is an example of a first beacon frame according to the present invention.

  This normal beacon frame is configured as a beacon frame during normal communication, transmitted during its own beacon slot for transmission, and by receiving beacon frames transmitted by surrounding wireless communication devices during the beacon period, Parameters are exchanged with the wireless communication device.

  As shown in FIG. 6, the normal beacon frame 60 includes MAC header information 61, a header check sequence (HCS) 62, beacon payload information 63, and a frame check sequence (FCS) 64.

  Further, the MAC header information 61 includes frame control information 601, a destination address 602 for identifying a destination wireless communication device, a source address 603 for identifying a source wireless communication device, and sequence control information 604 such as a sequence number. , And access control information 605 describing parameters necessary for access control.

  The beacon payload information 63 includes unique information 606 that is a parameter unique to the wireless communication device, beacon usage information 607 that indicates the use of the beacon slot, capability information 608 that indicates the capability of the wireless communication device, and hibernation mode. The sleep mode information 609 added when operating, the DRP reservation information 610 for notifying the MAS position where the DRP reservation is made, the DRP usage information 611 indicating the MAS position available for the DRP reservation, and the PCA communication It consists of PCA usage information 612 indicating the MAS position that may be used, a transmission display 613 indicating that there is data to be transmitted to the receiving wireless communication apparatus, and the like.

(7) Hibernation mode information element configuration example (Fig. 7)
FIG. 7 is a configuration example of the hibernation mode information element.
This hibernation mode information element details the contents of the information element configured as the sleep mode information 609 in FIG. This hibernation mode information element is a parameter added to the beacon before transitioning to the sleep state in the hibernation mode.

  As shown in FIG. 7, the hibernation mode information element includes an element identifier 614 indicating that it is a hibernation mode information element, an information length 615 of this information element, and the number of superframes until the hibernation operation starts. Consists of parameters such as a countdown 616, a hibernation sleep duration 617 indicating the number of superframes that perform a sleep operation in hibernation, and a hibernation active period 618 indicating the number of superframes that become active after the hibernation operation according to the present embodiment Is done.

  The normal beacon frame 60 has been described above. In the normal beacon frame 60 shown in FIG. 6, the MAC header information 61, the HCS 62, and the FCS 64 are fixed length data. The beacon payload information 63 includes fixed length data and variable length data. That is, the unique information 606 and the sleep mode information 608 are fixed-length data, and other beacon usage information 607, capability information 608, DRP reservation information 610, DRP usage information 611, PCA usage information 612, transmission display 613, etc. are variable length. It is data. These information elements may be added or deleted as necessary to form the normal beacon frame 60.

(8) Configuration example of shortened beacon frame (FIG. 8)
FIG. 8 shows a configuration example of a shortened beacon frame. This shortened beacon frame is an example of a second beacon frame according to the present invention.

  This shortened beacon frame is used, for example, when the hibernation mode is repeated, and is transmitted during its own transmission beacon slot period of the super frame. In the present embodiment, the parameters of the shortened beacon frame include the following information elements obtained by removing the reservation information from the normal beacon frame 60 described above.

  As shown in FIG. 8, the shortened beacon frame 70 includes MAC header information 71, a header check sequence (HCS) 72, beacon payload information 73, and a frame check sequence (FCS) 74.

  Further, the MAC header information 71 includes frame control information 701, a destination address 702 for identifying a destination wireless communication device, a source address 703 for identifying a source wireless communication device, and sequence control information 704 such as a sequence number. , And access control information 705 describing parameters necessary for access control.

  The beacon payload information 73 includes unique information 706 that is a parameter unique to the wireless communication device, beacon usage information 707 that indicates the use of the beacon slot, capability information 708 that indicates the capability of the wireless communication device, and hibernation mode. It consists of sleep mode information 709 added when operating.

(9) Simple beacon frame configuration example (FIG. 9)
FIG. 9 shows a configuration example of a simple beacon frame. This simple beacon frame is an example of the third beacon frame according to the present invention.

  This simple beacon frame repeats hibernation mode, and when there is no demand for data transmission and reception, and temporarily exists in a deep sleep state, this beacon frame consists of fixed-length frames that simply exchange parameters. Defined. The case of entering a deep sleep state temporarily is, for example, a case where the hibernation mode is set for a certain period or more, or a case where data transmission / reception is not performed for a certain period or more. In the present embodiment, the simple beacon frame parameters include the following information elements obtained by removing variable length data from the normal beacon frame 60.

  As shown in FIG. 9, the simple beacon frame 80 includes MAC header information 81, a header check sequence (HCS) 82, beacon payload information 83, and a frame check sequence (FCS) 84.

  Further, the MAC header information 81 includes frame control information 801, a destination address 802 for identifying a destination wireless communication device, a source address 803 for identifying a transmission source wireless communication device, and sequence control information 804 such as a sequence number. , And access control information 805 describing parameters necessary for access control.

  The beacon payload information 83 includes unique information 806, which is a parameter unique to the wireless communication device, and sleep mode information 807 added when operating in the hibernation mode.

(10) Operation of each wireless communication device in hibernation mode (FIG. 10)
FIG. 10 is a diagram illustrating the operation of each wireless communication device in the conventional hibernation mode. Here, one fixed beacon slot is arranged in each wireless communication device, and each enters a hibernation operation at an independent timing, and a state in which activation / sleeping is repeated at an independent timing is shown.

  For example, since the wireless communication device # 1 that uses the beacon slot 2 (BS2) is always in an active state, it represents a state in which a beacon is transmitted every time. In addition, the wireless communication device # 2 using the beacon slot 3 (BS3) becomes active in the superframe-1 and the superframe-5, but other than that operates in the hibernation mode, so that the beacon transmission is in a sleep state. ing. Similarly, wireless communication device # 3 using beacon slot 4 (BS4) becomes active in superframe-0 and superframe-4, but otherwise operates in hibernation mode, so that the beacon transmission is in a sleep state. Represents.

  Similarly, the wireless communication device # 4 using the beacon slot 5 (BS5) becomes active in the superframes 1, 3, 5, and 7, but other than that, it enters the hibernation mode, so that the beacon transmission is in a sleep state. Represents. The wireless communication device # 5 using the beacon slot 6 (BS6) operates in an active state until the superframe-4, but enters the hibernation mode after the superframe-5 and sleeps the beacon transmission. Represents a state.

  Further, the wireless communication device # 6 using the beacon slot 7 (BS7) is active only in the superframe-6, but otherwise, the wireless communication device # 6 operates in the hibernation mode. In addition, the wireless communication device # 7 using the beacon slot 8 (BS8) becomes active in the superframes 0, 3, 4, and 7, but other than that, the wireless communication device # 7 enters the hibernation mode, and thus the beacon transmission is in a sleep state. ing. In addition, the wireless communication device # 8 using the beacon slot 9 (BS9) is in a sleep state until the superframe-2, but is in an active state after the superframe-3 and transmits a beacon every time. Represents.

(11) An example of repeated use of a beacon slot (FIG. 11)
FIG. 11 is an example of repeated use of the beacon slot according to the present embodiment.
Here, a configuration example is shown in which the beacon slot 1 (BS1) is a beacon slot that is repeatedly used.

  In beacon slot 1 (BS1), superframe-0 transmits beacon B1 of wireless communication device # 1, superframe-1 transmits beacon B2 of wireless communication device # 2, and superframe-2 The beacon B3 of the wireless communication device # 3 is transmitted, the beacon B4 of the wireless communication device # 4 is transmitted in superframe-3, and the beacon B5 of the wireless communication device # 5 is transmitted in superframe-4. -5 is transmitted by the beacon B6 of the wireless communication device # 6, super frame -6 is transmitted by the beacon B7 of the wireless communication device # 7, and super frame -7 is transmitted by the beacon B8 of the wireless communication device # 8. It is configured to be.

  In this embodiment, a case where beacon slot 1 (BS1) is defined as a beacon slot shared by wireless communication apparatuses # 1 to # 8 will be described, but other beacon slots may be used. Such shared beacon slots can be defined in various ways. For example, it may be predefined as a wireless communication protocol (specification). It may also be defined when an ad hoc network is constructed. Further, in the ad hoc network, the wireless communication device may be defined by a wireless communication device that first transits to the hibernation mode when there is no wireless communication device that operates in the hibernation mode. Alternatively, a wireless communication device that is about to transition to hibernation mode can exchange information with another wireless communication device that is already operating in hibernation mode, thereby defining a shared beacon slot. Also good.

(12) Beacon slot usage example (Fig. 12)
FIG. 12 is an explanatory diagram showing an example of using an actual beacon slot.
Here, an example is shown in which a part of wireless communication devices constituting one network group repeatedly uses a beacon slot.

  The active wireless communication apparatus # 1 shows a state in which its own normal beacon is transmitted in beacon slot 2 (BS2). The active wireless communication apparatus # 2 shows a state in which its own normal beacon is transmitted in the beacon slot 3 (BS3). The wireless communication apparatus # 3 that continues the hibernation mode shows a state in which a shortened beacon or a simple beacon is transmitted at beacon slot 1 (BS1), for example, at offset-0. The active wireless communication apparatus # 4 indicates a state in which its own normal beacon is transmitted in the beacon slot 4 (BS4). The wireless communication device # 5 that continues the hibernation mode also shows a state of transmitting a shortened beacon or a simple beacon at beacon slot 1 (BS1), for example, at offset-1.

  The active wireless communication device # 6 indicates a state in which its own normal beacon is transmitted in the beacon slot 5 (BS5). The wireless communication device # 7 that continues the hibernation mode shows a state of transmitting a shortened beacon or a simple beacon at beacon slot 1 (BS1), for example, at offset-2. The wireless communication apparatus # 8 that continues the hibernation mode also shows a state of transmitting a shortened beacon or a simple beacon at beacon slot 1 (BS1), for example, at offset-3.

  In the example shown in FIG. 3, the beacon used by each wireless communication device constituting one network group is notified by notifying a beacon slot that is not used with surrounding wireless communication devices. The case where a slot is selected has been described. In the example of FIG. 3, one beacon is set in one beacon slot regardless of the communication status (operation mode) of each wireless communication device. In this regard, in the example of FIG. 12, since the same beacon slot can be used in the wireless communication apparatus in the hibernation mode, the beacon period can be set short.

(13) An example of switching the operation mode (FIG. 13)
FIG. 13 shows an example in which the continuation of the hibernation mode is interrupted and the operation mode is switched as an active wireless communication device.

  Here, when a transition is made from the state in which the hibernation mode is continued to the active operation mode, such as when data transmission occurs in the wireless communication apparatus # 3, the beacon transmission as the offset-0 of the beacon slot 1 (BS1) is stopped, A configuration is shown in which a normal beacon is transmitted by declaring the use of a new unique beacon slot 6 (BS6) that is not used by surrounding wireless communication devices.

  By adopting such a configuration, a normal beacon describing a beacon parameter necessary for data transmission / reception can be exchanged in each wireless communication device according to communication demand.

(14) Configuration example of wireless communication device (FIG. 14)
FIG. 14 is an explanatory diagram illustrating a configuration example of the wireless communication apparatus according to the present embodiment.

  As shown in FIG. 14, the wireless communication device 900 has an antenna 901 for transmitting and receiving a predetermined high-frequency wireless signal on a wireless medium, amplifies the received high-frequency signal, converts it to a received signal, and amplifies the signal to be transmitted. A high-frequency radio processing unit 902 that converts the signal into a high-frequency signal; a physical layer baseband unit 903 that performs a predetermined demodulation process on a desired received signal to construct an information bit; modulates an information bit to be transmitted; , Is configured.

  The wireless communication device 900 further includes a beacon signal analysis unit 904 that analyzes beacons of wireless communication devices existing in the vicinity, a peripheral device management unit 905 that stores parameters such as information described in the collected beacons, , A parameter management unit 906 for managing parameters of a beacon to be transmitted, a normal beacon generation unit 907 for generating a normal beacon transmitted by itself, management of its own hibernation mode, hibernation period and The configuration includes a hibernation unit 908 that manages the setting status of the offset, and a shortened beacon generation unit 909 that generates a shortened beacon or a simple beacon during the hibernation operation. The hibernation unit 908 is also provided with an offset setting management unit 908a that sets a superframe in which the hibernation beacon slot operates as an offset value when the hibernation beacon slot is shared with other wireless communication devices.

  In this embodiment, the short beacon generation unit 909 is described as generating both a short beacon and a simple beacon. However, the present invention is not limited to this, and a short beacon generation unit that generates a short beacon, And a simple beacon generation unit that generates a separate function unit.

  The operation in the hibernation mode according to the present embodiment is configured such that the hibernation unit 908 and the shortened beacon generation unit 909 operate, and low power consumption operation can be achieved by putting other functional units in a sleep state. The configuration is shown.

  The wireless communication apparatus 900 includes an access control unit 910 that performs data transmission / reception operations in a predetermined procedure in an active superframe, a data buffer 911 that temporarily stores data to be transmitted and received, A buffer management unit 912 that manages the storage location, and an application interface 913 that receives transmission data from an application device connected to the wireless communication apparatus and passes the received data to the application device. The The access control unit 910 includes a transmission / reception setting management unit 910a for setting transmission / reception when data is transmitted / received.

  Further, the wireless communication apparatus 900 includes a user interface 914 for displaying the operation status of the wireless communication apparatus to the user and receiving necessary instructions from the user, a series of operations of the wireless communication apparatus 900, and the present embodiment. As a hibernation operation, a storage unit 915 for storing parameters such as sleep superframe sleep period information, active superframe operation period information, transmission DRP setting information, and usable MAS information, and the wireless communication apparatus A central control unit 916 that centrally manages the operation of 900 is configured.

(15) Operation flow of wireless communication device (FIG. 15)
FIG. 15 is a diagram illustrating an operation flow of the wireless communication device.
Here, a description will be given of an operation flow on the assumption that the processing after the predetermined power-on has already been completed and a steady operation is performed.

  First, if it is an active operation mode (S101), within the beacon period (S102), if it is its own beacon slot position (S103), information on normal beacons is created (S104), and beacon transmission processing is performed (S116). .

  If a beacon is received other than its own beacon slot (S105), and if it is a hibernation beacon slot (S106), information on the hibernation offset value of the wireless communication device performing the hibernation operation is acquired (S107), and then The received beacon parameters are stored (S108). Furthermore, if a reception request is issued to itself by the corresponding beacon (S109), the response parameter is set if necessary (S110), and data reception is set at a designated timing (S111). Here, if the self is operating in the hibernation mode (S112), the existing beacon parameters are acquired, the free information of the normal beacon slot is acquired (S118), and the normal beacon slot used by itself is set. Perform (S119).

  On the other hand, if operating in the hibernation mode in S101, when a superframe in which the self becomes active arrives (S113), information on a shortened beacon is created in the hibernation beacon slot (S114) (S115), Transmission processing is performed (S116). If it is a superframe in which it is active and it is not a hibernation beacon slot, the process proceeds to S102, and beacon reception processing is performed within the beacon period.

  Further, when the self-activation request is accepted except for the super frame in which the self is active (S117), the free information of the normal beacon slot is acquired (S118), and the normal beacon slot used by the self is set (S119). If the self-start request is not accepted, the sleep state is continued. If it is outside the beacon period, when the data transmission timing set in the previous process arrives (S120), the transmission data is acquired (S121), and the designated data transmission process is performed (S122).

  When the data reception timing set in the previous process arrives (S123), a data reception process is performed (S124), and the received data is stored (S125). Further, when data to be transmitted via the interface is accepted (S126), a data transmission request is set in its own transmission beacon (S127), and data transmission is set (S128).

  For example, if there is no data to be transmitted over a predetermined time and no received data, it is determined whether transition to the hibernation mode is possible (S129), and an offset value of the surrounding hibernation beacon slot is obtained (S130). , A value in an unused state is set as its own offset (S131), and a transition is made to the hibernation mode.

  The configuration and operation of the wireless communication device 900 have been described above as an example of the wireless communication device of the present invention. The wireless communication device 900 can cause the computer to function as the wireless communication device 900 by incorporating a computer program for realizing the above functions into the computer. Such a computer program can be distributed in the market in a form recorded on a predetermined recording medium (for example, a CD-ROM) or downloaded via an electronic network.

(Effect of this embodiment)
As described above, according to the present embodiment, the same space can be obtained by switching and transmitting the shortened beacon frame 70 in which reservation information or the like is not described, or the simpler beacon slot 80 excluding variable length data. Even if there are a large number of wireless communication devices on the top, it is possible to effectively avoid a decrease in the number of beacon slots. Furthermore, it is possible to simplify the processing of the wireless communication device operating in the hibernation mode and realize low power consumption operation.

  Furthermore, there is an effect that the existence of all the wireless communication devices in the hibernation mode can be easily grasped only by receiving the same beacon slot (BS1). In addition, by sharing the beacon slot of the wireless communication device in the hibernation mode, it is possible to compensate for the shortage of the absolute number of beacon slots.

  Furthermore, the beacon slot of the wireless communication device operating in the hibernation mode is activated at the timing when the same slot has a different offset value for each superframe, and when the active operation mode is entered, the normal beacon slot By transmitting a beacon with, the shortage of the number of beacon slots can be solved.

  The preferred embodiments of the wireless communication apparatus and the wireless communication system according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, in the above embodiment, the shortened beacon frame generation unit 907 generates the shortened beacon frame 70 when the hibernation mode is set or when data transmission / reception is not performed, and the hibernation mode is set for a certain period or longer. Although the case where the simple beacon frame 80 is generated when it is set or when data transmission / reception is not performed has been described, the present invention is not limited to this. Instead of generating the simple beacon frame 80, only the normal beacon frame 60 and the shortened beacon frame 70 may be switched for transmission.

  The shortened beacon frame generation unit 907 can also generate the simple beacon frame 80 immediately when the hibernation mode is set or when data transmission / reception is not performed. In this case, the shortened beacon frame generation unit 907 performs transmission by switching between the normal beacon frame 60 and the simple beacon frame 80 without generating the shortened beacon frame 70.

(Industrial applicability)
The present invention can be used for a wireless communication device and a wireless communication system, and in particular, can be used for a wireless communication device and a wireless communication system that form an autonomous distributed ad hoc network with surrounding wireless communication devices.

It is explanatory drawing which shows the structural example of a wireless ad hoc network. It is explanatory drawing which shows the example of a super-frame structure. It is explanatory drawing which shows the usage setting example of a beacon slot. It is explanatory drawing which shows the operation example of hibernation mode. It is explanatory drawing which shows the setting of a hibernation offset. It is explanatory drawing which shows the structural example of a normal beacon frame. It is explanatory drawing which shows the structural example of a hibernation mode information element. It is explanatory drawing which shows the structural example of a shortened beacon frame. It is explanatory drawing which shows the structural example of a simple beacon frame. It is explanatory drawing which shows operation | movement of each radio | wireless communication apparatus in hibernation mode. It is explanatory drawing which shows an example of repeated use of a beacon slot. It is explanatory drawing which shows the usage example of a beacon slot. It is explanatory drawing which shows an example in the case of switching operation modes. It is explanatory drawing which shows the structural example of a radio | wireless communication apparatus. It is explanatory drawing which shows the operation | movement flow of a radio | wireless communication apparatus.

Explanation of symbols

60 Normal beacon frame (first beacon frame)
70 shortened beacon frame (second beacon frame)
80 Simple beacon frame (third beacon frame)
100 Ad-hoc network 111, 112,..., 118 Wireless communication device 121, 121,..., 128 Radio wave reachable range 900 Wireless communication device 901 Antenna 902 Peripheral device management unit 906 Parameter management unit 907 Normal beacon generation unit (first beacon frame generation unit)
908 hibernation unit 908a offset setting management unit 909 shortened beacon generation unit (second and third beacon frame generation unit)
910 Access control unit 910a Transmission / reception setting management unit 911 Data buffer 912 Buffer management unit 913 Application interface 914 User interface 915 Storage unit

Claims (10)

  1. In an ad hoc network wireless communication device that transmits and receives beacon frames at a predetermined cycle,
    A first beacon frame generating unit that generates a first beacon frame including variable length data including reservation information and fixed length data ;
    A second beacon frame generation unit for generating a second beacon frame obtained by removing the reservation information from the first beacon frame;
    With
    A wireless communication apparatus, wherein the first and second beacon frames are switched and transmitted.
  2.   The wireless communication apparatus according to claim 1, wherein the second beacon frame generation unit generates the second beacon frame when data transmission / reception is not performed.
  3.   The wireless communication apparatus according to claim 1, wherein the second beacon frame generation unit generates the second beacon frame when a hibernation mode for performing a temporary sleep operation is set. .
  4.   The wireless communication apparatus according to claim 3, wherein the first beacon frame generation unit generates the first beacon frame when the hibernation mode is changed to the normal operation mode.
  5. In an ad hoc network wireless communication device that transmits and receives beacon frames at a predetermined cycle,
    A first beacon frame generating unit that generates a first beacon frame including variable length data including reservation information and fixed length data ;
    A second beacon frame generation unit for generating a second beacon frame obtained by removing the reservation information from the first beacon frame;
    A third beacon frame generating unit for generating a third beacon frame obtained by removing the variable length data from the first beacon frame;
    With
    A wireless communication apparatus, wherein the first to third beacon frames are switched and transmitted.
  6. The second beacon frame generation unit generates the second beacon frame when data transmission / reception is not performed,
    The wireless communication apparatus according to claim 5, wherein the third beacon frame generation unit generates the third beacon frame when the transmission / reception of the data is not performed for a certain period or longer.
  7. The second beacon frame generation unit generates the second beacon frame when a hibernation mode for performing a temporary sleep operation is set,
    6. The wireless communication apparatus according to claim 5, wherein the third beacon frame generation unit generates the third beacon frame when the hibernation mode is set for a certain period or longer.
  8.   The radio communication apparatus according to claim 7, wherein the first beacon frame generation unit generates the first beacon frame when the hibernation mode is changed to the normal operation mode.
  9. A computer program for causing a computer to function as a wireless communication device of an ad hoc network that transmits and receives beacon frames at a predetermined cycle,
    Said computer,
    First beacon frame generating means for generating a first beacon frame including variable length data including reservation information and fixed length data ;
    Second beacon frame generating means for generating a second beacon frame obtained by removing the reservation information from the first beacon frame;
    Transmission means for switching and transmitting the first and second beacon frames;
    A computer program that functions as a computer.
  10. A computer program for causing a computer to function as a wireless communication device of an ad hoc network that transmits and receives beacon frames at a predetermined cycle,
    Said computer,
    First beacon frame generating means for generating a first beacon frame including variable length data including reservation information and fixed length data ;
    Second beacon frame generating means for generating a second beacon frame obtained by removing the reservation information from the first beacon frame;
    Third beacon frame generating means for generating a third beacon frame obtained by removing the variable length data from the first beacon frame;
    Transmission means for switching and transmitting the first to third beacon frames;
    A computer program that functions as a computer.

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