JP5761715B2 - TVWS channel allocation method - Google Patents

Description

  The present invention relates to a TVWS channel assignment method suitable for assigning a TVWS channel even in a device in which a communication enabler capable of communicating with a TVWS database is not installed.

  With the shift from analog TV to digital TV, some frequencies are released and those frequency bands are used for mobile communications. In particular, in recent years when new communication services and various applications are put into practical use one after another, the allocation of the radio band is subdivided and complicated. While the communication services allocated in this way are mixed in the radio band, it is gradually becoming difficult to allocate new communication services to the radio band.

  For this reason, in recent years, standardization of a wireless communication network using TV White Space (TVWS) has been promoted, and standardization of a method for coexisting IEEE 802 standards in TVWS has also been promoted (for example, see Non-Patent Document 1). .) For this reason, it becomes particularly important how these different IEEE 802 standard communication systems coexist in the same frequency band, and in particular, the importance has increased with the recent dramatic increase in radio communication opportunities.

  When actually using the TVWS frequency band, based on so-called cognitive radio communication, the secondary network detects the time when the TV broadcast as the primary network is not performed and the frequency band that is not used. Next, the secondary network confirms whether or not each device in the primary network performs interference by communication by a device belonging to its own system. Wireless communication is performed according to the band or time.

IEEE 802.af "Part11: Wireless Medium Control (MAC) and Physical Layer (PHY) Specification for Wireless Local Area Networks (WLANs): Operation in the TV White Spaces

  However, in TVWS, a fixed device composed of a router or the like that is always fixed and its own position information is known, a first mode device whose own position information is unknown, and a second mode whose own position information is known It can be classified into three types of devices. Of these, the fixed device and the second mode device are each equipped with a communication enabler capable of communicating with the TVWS database, and thus directly access the TVWS database via the communication enabler to obtain information on the empty channel. be able to. In contrast, the first mode device does not have a communication enabler that can communicate with the TVWS database. For this reason, in order to actually exchange information regarding an empty channel with the TVWS database, the first mode device first accesses a fixed device or a second mode device in the surrounding area and is mounted on them. Although it is necessary to access the TVWS database via a communication enabler, a method for realizing these efficiently and reliably has not been proposed in the past.

  Accordingly, the present invention has been devised in view of the above-described problems, and its object is to provide a TVWS channel in a first mode device in which a communication enabler capable of communicating with a TVWS database is not implemented. It is an object of the present invention to provide a TVWS channel allocation method capable of efficiently and reliably allocating.

  The TVWS channel allocation method according to claim 1 is a communication enabler capable of communicating between a TVWS database in which vacant information for each time and position in each channel of TVWS (TV White Space) is recorded, and the TVWS database. In the method for allocating a TVWS channel in a wireless communication system having a second mode device or a fixed device on which is mounted and a first mode device that is initially in an unenabled state because the communication enabler is not mounted, When the mode device receives the enable signal from the communication enabler, the first mode device shifts from the non-enabled state to the enable setup complete state, and sends an enable request to the communication enabler, and the communication enabler. In response to the enable request from the first mode device, the error response is returned and the enable setup completion state is shifted to the enable state, and the empty information received from the TVWS database is described. When a beacon frame is transmitted to the first mode device and the first mode device receives the beacon frame, a standby period is set and a connection confirmation signal is received from the communication enabler within the standby period. In the case where the enable state is maintained and wireless communication is performed based on the TVWS channel based on the empty information and a connection confirmation signal is not received from the communication enabler within the standby period, or An enable release request for releasing the enable state is received. If it is received, it returns to the non-enabled state.

  According to a second aspect of the present invention, there is provided a method for allocating a TVWS channel according to the first aspect of the present invention, wherein the first mode device does not receive the beacon frame in the enable setup completion state or receives the enable release request. In this case, the process returns to the non-enabled state.

  According to a third aspect of the present invention, there is provided a TVWS channel allocation method according to the first or second aspect of the invention, wherein the payload includes control information relating to each information element (IE) described thereafter. Information area, at least a list of frequency channels in TVWS, a frequency channel information area in which a list of channels that can be used through enable processing is described, a timing information area in which information on valid channel time zones is described, and a channel A beacon frame including a position information area in which information related to a position where is valid is described is transmitted.

  According to the present invention having the above-described configuration, the communication enabler mounted on the fixed device or the second mode device even if the position information of the device itself is unknown and the communication enabler is not mounted. The TVWS database can be accessed via the, and free information on the TV channel can be obtained therefrom. Therefore, the first mode device can easily check the currently available TV channel from the available information acquired via the communication enabler, and can select the available channel, time zone, and position. Communication can be started.

  For this reason, in the present invention, it is possible to efficiently and reliably allocate the TVWS channel even in the first mode device in which the communication enabler that can communicate with the TVWS database is not mounted. As a result, it is possible to avoid wasting time until the start of communication, and it is possible to eliminate waste of frequency resources.

It is a figure which shows the structural example of the channel allocation system to the TV band to which this invention is applied. It is a figure shown about transition of three statements in a 1st mode device. It is a flowchart which shows the state transition in a 1st mode device. It is a figure which shows the example of the beacon frame transmitted in step S21.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out a wireless communication method to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration example of a channel allocation system 1 to a TV band in TVWS (TV White Space) to which the present invention is applied. This channel allocation system 1 includes a TVWS database 2 in which vacant information for each time and position in each TVWS channel is recorded, and a fixed device 32 on which a communication enabler capable of communicating between the TVWS database is mounted, A wireless communication network 3 having a mode device 33 and a first mode device 31 that is initially in an unenabled state because the communication enabler is not implemented, and a public communication network 25 are provided. Incidentally, it is sufficient that only one of the fixed device 32 and the second mode device 33 is provided.

  The wireless communication network 3 performs wireless communication based on a wireless communication standard such as WPAN (Wireless Personal Area Network) or WLAN (Wireless Local Area Network). The present invention is particularly preferably used for the wireless communication network 3 that performs wireless communication based on the IEEE 802.15.4 standard WPAN. The first mode device 31 and the second mode device 33 in the wireless communication network 3 selectively use a TV band that is not currently used, thereby performing wireless communication using the TV band in the network. Can also be performed.

  The first mode device 31 and the second mode device 33 include, for example, personal computers (notebook PCs), mobile phones, and various portable information terminals such as high-function mobile phones. The first mode device 31 and the second mode device 33 can directly perform ad hoc wireless communication with each other in a time division manner in the wireless communication network 3 based on at least a standard such as WPAN and WLAN. It is also possible to perform indirect wireless communication with each other via the. The second mode device 33 is provided with a communication enabler (not shown). This communication enabler (not shown) plays a role as a translation means for realizing communication via the public communication network 25 between the second mode device 31 and the TVWS database 2. A communication enabler (not shown) relays communication between the second mode device 31 and the TVWS database 2.

  In contrast, the first mode device 31 is not equipped with such a communication enabler. Therefore, the first mode device 31 first accesses the surrounding fixed device 32 or the second mode device 33 in order to actually exchange information regarding the empty channel with the TVWS database 2, It is necessary to access the TVWS database 2 via the communication enabler implemented in the above.

  The fixed device 32 is a fixed device that exists in the wireless communication network 3, and is configured by, for example, a desktop PC. The fixed device 32 may be set to serve as a wireless access point by the first mode device 31 and the second mode device 33 and to serve as an interface with the public communication network 25. The first mode device 31 and the second mode device 33 can perform data communication with the public communication network 25 via other access points (not shown) themselves, and can also be made public via the fixed device 32. Data communication with the communication network 25 is also possible. The fixed device 32 is mounted with a communication enabler (not shown). This communication enabler (not shown) plays a role as a translation means for realizing communication via the public communication network 25 between the fixed device 32 and the TVWS database 2. A communication enabler (not shown) relays communication between the fixed device 32 and the TVWS database 2.

  The public communication network 25 includes an ISDN (Integrated Services Digital Network) / B (broadband)-connected to a TA / modem including an Internet network that connects the TVWS database 2 and the wireless communication network 3 via a telephone line. A network or the like that enables bidirectional transmission and reception of information, such as ISDN.

  The TVWS database 2 is a database in which vacant information in each TVWS channel is recorded. That is, for example, if the status of the frequency channel currently used by the television system is known, information regarding a currently available channel (hereinafter referred to as channel availability information) can be known at the same time. The TVWS database 2 records, as such channel vacancy information, channel vacancy time and channel vacancy position in each channel. By accessing such a TVWS database 2, it is possible to determine which TVWS channel can be used at what time and at what time.

  In the present invention configured as described above, each of the fixed device 32 and the second mode device 33 is equipped with a communication enabler, and thus can directly access the TVWS database 2 via the public communication network 25. From here, it becomes possible to obtain vacant information for each time and position in each channel of TVWS. As a result, the TVWS database 2 can communicate with the TV band frequency via the public communication network 25 in the time zone, channel, and position not used in TV broadcasting.

  On the other hand, the first mode device 31 in which the communication enabler is not mounted needs to access the TVWS database 2 via the communication enabler mounted in the fixed device 32 or the second mode device 33 as described above. There is.

  Hereinafter, a TVWS channel allocation method using a communication enabler installed in the first mode device 31 and the fixed device 32 or the second mode device 33 will be described in detail.

  FIG. 2 shows three statement transitions in the first mode device 31. The first mode device 31 can be broadly classified into three categories: a non-enable state, an enable setup completion state, and an enable state. The non-enable state here indicates a state in which the first mode device 31 is completely inaccessible to the TVWS database 2 via the communication enabler mounted on the fixed device 32 or the second mode device 33. . The enable setup completion state is a state in which the first mode device 31 enters a standby state for a beacon frame in which empty information is described via a communication enabler mounted on the fixed device 32 or the second mode device 33. Is shown. The enabled state refers to a state in which the first mode device 31 can indirectly access the TVWS database 2 via a communication enabler mounted on the fixed device 32 or the second mode device 33.

  First, the first mode device 31 waits for an enable signal from the communication enabler in the non-enabled state. When the first mode device 31 receives an enable signal from the communication enabler in the non-enabled state, the first mode device 31 shifts to an enable setup completion state. Incidentally, this enable signal may be included in a beacon. When a connection confirmation signal (Contact Verification signal; hereinafter referred to as CV signal) cannot be received in the enable setup completion state, or when an enable release request is received, the state returns to the non-enable state again. On the other hand, when the first mode device 31 receives the enable response signal in the enable setup completion state, the state shifts to the enable state.

  When the first mode device 31 shifts to the enable state, the first mode device 31 accesses the TVWS database 2 via the communication enabler, and communicates with the frequency of the TVWS band in the time zone, channel, and position that are not used in TV broadcasting. Can be performed. At this time, by continuing to receive the CV signal, the enable state is maintained. However, when the CV signal cannot be received or when an enable release request is received, the non-enable state is again entered. Will return.

  Hereinafter, the flow of these state transitions between the first mode device 31 and the communication enabler mounted on the fixed device 32 or the second mode device 33 will be described.

  FIG. 3 is a flowchart showing the state transition process. These processes are executed between the first mode device 31 and the communication enabler 35 mounted on the fixed device 32 or the second mode device 33. Specifically, in the first mode device 31, This is performed via MLME (MAC Layer Management Entity) 31a and DME (DME: Device Management Entity) 31b, and MLME 35a and DME 35b in communication enabler 35. The MLMEs 31a and 35a are for managing predetermined operations related to the MAC layer, and the DMEs 31b and 35b are for managing the entire device and enabler, respectively.

  At the start of this flow, when the first mode device 31 is in the non-enabled state, the DME 35b in the communication enabler 35 first transmits a start request for transmitting an enable signal to the MLME 35a in step S11. . In response to the start request, the MLME 35a transmits an enable signal to the MLME 31a in the first device 31 (step S12). When the MLME 31a receives the enable signal, the MLME 31a transmits a signal reception notification for notifying the fact to the DME 31b (step S13). When the DME 31b receives the signal reception notification, the first mode device 31 shifts from the non-enabled state to the enable setup complete state.

  In the enable setup completion state, processing within the range surrounded by the dotted line is executed. First, an enable request is notified from the DME 31b to the MLME 31a (step S14). When receiving the enable request, the MLME 31a generates an enable request signal and transmits it to the MLME 35a in the communication enabler 35 (step S15). When the MLME 35a receives the enable request signal, the MLME 35a transmits an enable request instruction based on the enable request signal to the DME 35b (step S16).

  Next, the DME 35b receives the enable request instruction and notifies the MLME 35a of an enable response to the enable request instruction (step S17). In response to this, the MLME 35a transmits an enable response signal to the MLME 31a in the first mode device 31 (step S18). When the enable response signal is received, the state shifts from the enable setup completion state to the enable state. When the MLME 31a receives the enable response signal, the MLME 31a notifies the DME 31b of an enable response confirmation (step S19).

  Next, in step S20, the DME 35b in the communication enabler 35 notifies the beacon transmission request to the MLME 35a. In response to the beacon transmission request, the MLME 35a transmits a beacon frame to the MLME 31a in the first mode device 33 (step S21). The beacon frame transmission process in step S21 is the same as the enable signal transmission process in step S12. For this reason, step S21 may be introduced into the process as an option, or may be omitted by including it in step S12. In such a case, the beacon frame in step S21 is sent as the enable frame in step S12.

  Incidentally, in this beacon frame, empty information received from the TVWS database 2 is described. As described above, this vacant information is composed of the time and position at which each TVWS channel is vacant. When the MLME 31a receives such a beacon frame, the MLME 31a transmits a reception notification to that effect to the DME 31b (step S22). The DME 31b can receive channel reception information in the TV band described above upon receiving such reception notification.

  Incidentally, if the first mode device 31 cannot receive this beacon frame through the processing of steps S20 to S22, or if it receives an enable release request, it returns to the non-enabled state.

  The DME 31b that has transitioned to the enable state requests data in step S23. In response to the data request, the MLME 31a transmits a request frame to the MLME 35a in the communication enabler 35 (step S24). The MLME 35a that has received this request frame transmits a request to that effect to the DME 35b (step S25).

  The first mode device 31 sets a standby period having a predetermined length when a beacon frame is received in step S21. This standby period is for waiting for a CV signal transmitted from the communication enabler 35.

  In response to the step request notification in step S25 described above, the DME 35b transmits a CV signal transmission instruction to the MLME 35a (step S26). When receiving the CV signal transmission instruction, the MLME 35a transmits the CV signal to the first mode device 31b (step S27). When the MLME 31a can capture the CV signal within the standby period, the MLME 31a proceeds to step S28 and notifies the DME 31b that the CV signal has been received (step S28). ). By receiving the notification, the DME 31b can identify that the first mode device 31 has received the CV signal, and continues to maintain the enabled state. On the other hand, if the CV signal cannot be received within the standby period in step S27, it can be identified that the first mode device 31 has not been able to receive the CV signal. It becomes possible to release the enable state and return to the non-enable state. Incidentally, in this standby period, when an enable release request other than the above-described CV signal is notified, the non-enable state is similarly returned.

  Through the above-described flow, even if the first mode device 31 has its own position information unknown and no communication enabler is mounted, it does not pass through the communication enabler mounted on the fixed device 32 or the second mode device 33. The TVWS database 2 can be accessed, and from there, vacant information regarding the TV channel can be acquired. For this reason, the first mode device 31 can easily check the currently available TV channel from the available information acquired via the communication enabler, and selects the available channel, time zone, and position. Communication can be started.

  Therefore, in the present invention, the TVWS channel can be allocated efficiently and reliably even in the first mode device 31 in which the communication enabler that can communicate with the TVWS database is not mounted. As a result, it is possible to avoid wasting time until the start of communication, and it is possible to eliminate waste of frequency resources.

  FIG. 4 shows an example of a beacon frame transmitted in step S21. The preamble 11 provided at the head is followed by a header 12 in which various management information is written, and a payload 13 in which actual data is written.

  In the payload 13, an IE (Information Elements) control information area 14, a frequency channel information area 15, a timing information area 16, a position information area 17, and an output control information area 18 are written. The IE control information area 14 includes control information related to each information element (IE) described thereafter. The frequency channel information area 15 describes a list of frequency channels in TVWS, a list of channels that can be used through enable processing, and the like. In the timing information area 16, it is described in which time zone the effective channel is effective. In the position information area 17, information on the position where the channel is effective is described so that the first mode device 31 can easily switch to the effective channel. Further, in the output control information area 18, information related to operation output proposed from the viewpoint of achieving better coexistence with the TV system is described.

  By acquiring the beacon frame having the above-described configuration, the first mode device 31 can easily check the currently available TV channel, and the available channel, time zone, position It becomes possible to select and start communication.

1 channel allocation system 2 TVWS database 3 wireless communication network 11 preamble 12 header 13 payload 14 control information area 15 frequency channel information area 16 timing information area 17 position information area 18 output control information area 25 public communication network 31 first mode device 32 fixed Device 33 Second mode device

Claims (3)

A second mode device or a fixed device in which a TVWS database in which vacant information for each time and position in each channel of TVWS (TV White Space) is recorded and a communication enabler capable of communicating with the TVWS database are mounted; In the method for allocating a TVWS channel in a wireless communication system having a first mode device that is initially in an unenabled state because the communication enabler is not implemented,
When the first mode device receives the enable signal from the communication enabler, the first mode device shifts from the non-enabled state to the enable setup complete state and makes an enable request to the communication enabler.
When the communication enabler receives the enable request from the first mode device, it returns an enable response and shifts from the enable setup completion state to the enable state, and the empty information received from the TVWS database is described. Transmitted beacon frame to the first mode device,
When the first mode device receives the beacon frame, a standby period is set. When the connection confirmation signal is received from the communication enabler within the standby period, the enable state is maintained. Wireless communication is performed based on the TVWS channel based on the vacant information and a connection confirmation signal is not received from the communication enabler within the standby period, or an enable cancellation request for canceling the enabled state is issued. A TVWS channel allocation method, comprising: returning to the non-enabled state when received. 2. The non-enable state is returned when the first mode device does not receive the beacon frame or receives the enable release request in the enable setup completion state. TVWS channel allocation method. The payload includes an IE (Information Elements) control information area including control information on each information element (IE) described later, at least a list of frequency channels in the TVWS, and a channel that can be used through enable processing. A beacon frame including a frequency channel information area in which a list of channels is described, a timing information area in which information on valid channel time zones is described, and a position information area in which information on positions where channels are valid are described are transmitted. The method of allocating a TVWS channel according to claim 1 or 2.

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