KR100673814B1 - Active pnc handover method in wpan - Google Patents

Abstract

The present invention relates to an active PNC handover method in a wireless fan environment. In particular, the present invention relates to a PNC handover selection order (S) of a current state, and to a non-received beacon (LB) set to "0". 1 step (S1); Waiting for the beacon and determining whether the beacon has been received (S2); Receiving a beacon, after resetting the number of beacons (LB) that have not been continuously received to “0”, a third step (S3) of checking a PNC selection order included in the received beacon; A fourth step S4 of determining whether to change the PNC selection order; And a fifth step S5 of waiting for the beacon after resetting the PNC selection order S to the PNC selection order included in the received beacon when the selection order of the PNC is changed, and then waiting for the beacon. The present invention has the effect of solving the problem that the existing piconet may be broken during the PNC handover process and a problem that takes a long time to select a new PNC.

Wireless fan environment, active PNC handover, piconet,

Description

Active PNC HANDOVER METHOD IN WPAN in Wireless Fan Environments             

1 is a piconet configuration in a typical wireless fan environment,

2 is an operational flowchart illustrating an active PNC handover method in a wireless fan environment according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: DEV (device) 20: PNC (Piconet Coordinator)

The present invention relates to an active PNC (Piconet Coordinator) handover method in a wireless fan environment, and more particularly, to select a new PNC using a PNC selection order and a number of beacons that cannot be continuously received. By using the probe request command and the immediate response request (Imm_ACK) in calculating the number of beacons that cannot be received continuously, the piconet saves time for PNC selection and handover. The present invention relates to an active PNC handover method in a wireless fan environment that does not collapse.

As is well known, basically the IEEE 802.15.3 standard specification (IEEE Std 802.15.3, September 2003) is based on a maximum of 243 activated DEV (device) 10 and one PNC 20, as shown in FIG. It consists of a piconet (Piconet). At this time, the PNC 20 manages basic timing of the piconet using a beacon frame. In addition, the PNC 20 manages quality of service (QoS) and power save (Power Save) modes, and controls access to the piconet when security is implemented.

However, since the beacon frame holding the overall information of the piconet does not retransmit and acknowledge, if the beacon frame is lost or not received, the DEVs of the network cannot perform normal communication. When power is suddenly turned off or the piconet is left without a normal handover procedure to transfer the PNC to another DEV, there is a problem that the network itself is broken due to the absence of the PNC managing the piconet.

On the other hand, if all DEVs do not arrive in succession of beacon frames during the four superframe periods, they each start a channel scan as at the initial start of the piconet. As a result, not only data transmission is impossible for a considerable time to set up a new PNC, but also some DEVs are out of the propagation range of the newly set PNC, and thus, they have to form a dependent piconet again.

Therefore, in the existing wireless fan environment, there was a problem in that the piconet was broken and a long time was taken to select a new PNC.

Accordingly, the present invention has been made to solve the conventional problems as described above, an object of the present invention is to solve the problem that the existing piconet may be broken during the PNC handover process and the problem that takes a long time to select a new PNC. The present invention provides an active PNC handover method in a wireless fan environment.

In order to achieve the above object, the active PNC handover method in the wireless fan environment of the present invention basically has a Contention Access Period (CAP) period, and the PNC can always transmit a command during the CAP period. In the active PNC handover method of setting the mode, and allowing up to four candidates that can operate with the PNC,

Setting a PNC handover selection order S of a current state and setting a number of beacons LB not received to " 0 ";

Waiting for the beacon and determining whether the beacon has been received;

Receiving a beacon in the second step, resetting the number of beacons (LB) that have not been continuously received to "0", and then checking a PNC selection order included in the received beacon;

A fourth step of determining whether to change the PNC selection order; And

If the selection order of the PNC is not changed in the fourth step, the process proceeds to the second step again and waits for the beacon. If the selection order of the PNC is changed, the PNC selection order (S) is changed to the PNC selection order included in the received beacon. After resetting, the process proceeds to the second step again, wherein a fifth step of waiting for the beacon is performed.

Hereinafter, an active PNC handover method in a wireless fan environment according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 is a block diagram showing a piconet configuration in a general wireless fan environment as described above, the present invention is applied to the piconet as shown in FIG.

Then, a method of active PNC handover in a wireless fan environment according to an embodiment of the present invention will be described with reference to FIG. 2. Basically, the PNC 20 is a content access access period (CAP) competition approach. Period). It is an active PNC handover method that sets a mode that can always transmit a command during the CAP period and allows up to four candidates that can operate as the PNC 20.

First, the PNC handover selection order S of the current state is set, and the number of beacons LB not received is set to "0" (S1).

Then, while waiting for the beacon (Beacon) it is determined whether the beacon has been received (S2). At this time, if the beacon is received in the second step (S2) (YES), the number of beacons (LB) that have not been received continuously is reset to "0", and then the PNC selection order included in the received beacon is examined. (S3). Next, it is determined whether the PNC selection order is changed (S4).

If the selection order of the PNC 20 is not changed in the fourth step S4 (NO), the process proceeds to the second step S2 again and waits for a beacon while the selection order of the PNC 20 is changed (YES). After resetting the PNC selection order (S) to the PNC selection order included in the received beacon, the process proceeds to the second step S2 again and waits for the beacon (S5).

On the other hand, if the beacon is not received in the second step (S2) (NO), the number of beacons (LB) that have not been continuously received is increased to “1” (S6). Then, it is determined whether the number of beacons (LB) that have not been successively received is smaller than "9" which is smaller than the number added by "4" to the PNC selection order S, and "1" which is larger than "1" by twice the number of PNC candidates. It is determined (S7).

At this time, the number of beacons LB that have not been continuously received in the seventh step S7 is smaller than the number added by "4" to the PNC selection order S and is larger by "1" than twice the number of PNC candidates. If less than "9" (YES), the six-byte information request field is set to "0" during the CAP period, and a probe request command for requesting immediate reception status (Imm_ACK) is transmitted to the PNC 20 (S8). .

Next, it is determined whether or not "Imm_ACK" is received (S9). At this time, if the "Imm_ACK" is not received in the ninth step S9 (NO), it is determined whether there is a fixedly available channel allocation (PS CTA) (S10).

In the tenth step (S10), if there is a stationary channel assignment (Pseudo Static CTA) that can be used (YES), a message asking whether to receive a beacon during the "PS CTA" and an immediate response when the beacon is received A probe request command requesting (Imm_ACK) is transmitted to the corresponding destination DEV 10 (S11). Then, it is determined whether or not "Imm_ACK" is received (S12).

At this time, if the "Imm_ACK" is not received in the twelfth step S12 (NO), whether the beacon number LB that has not been continuously received is smaller than the number greater than "3" than the PNC selection order S. Determine (S13). If the number of beacons (LB) that are not continuously received in the thirteenth step (S13) is smaller than the number larger than "3" (YES) than the PNC selection order (S), the process proceeds to the second step (S2) again. If large (NO) a new beacon is generated by the new PNC and transmitted (S14).

Meanwhile, the beacon number LB that has not been continuously received in the seventh step S7 is smaller than the number added by "4" to the PNC selection order S, and is "1" larger than the number of PNC candidates twice. If the result of determining whether it is smaller than 9 "is false (NO), or receives" Imm_ACK "in the ninth step (S9) (YES), or receives" Imm_ACK "in the twelfth step (S12) (YES) ), The number of beacons (LB) that have not been continuously received is reset to "0" and then proceeds to the second step S2 again (S15).

In addition, in the tenth step (S10), if there is no fixedly available channel assignment (PS CTA) (NO), the message asking whether to receive a beacon during the "PS CTA" and immediately if a beacon is received The probe request command for requesting a response (Imm_ACK) is transmitted to another DEV 10 based on the previously communicated content and the PNC selection order information, and then the process proceeds to the twelfth step S12 again.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

Although the present invention has been described in more detail with reference to some embodiments, the present invention is not necessarily limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention.

As described above, according to the active PNC handover method in the wireless fan environment according to the present invention, in order to solve the problem that the existing piconet breaks down and takes a long time to select a new PNC, By selecting a new PNC using the number of beacons that cannot be continuously received, and using a probe request command and an immediate response request (Imm_ACK) in calculating the number of beacons that are not continuously received. This saves time for PNC selection and handover, as well as preventing the piconet from breaking down.

Claims (4)

By default, the PNC has a Contention Access Period (CAP) period. In the active PNC handover method that is set to the mode that can always transmit a command during the CAP interval, and allows up to four candidates that can operate as a PNC, Setting a PNC handover selection order S of a current state and setting a number of beacons LB not received to " 0 "; Waiting for the beacon and determining whether the beacon has been received; Receiving a beacon in the second step, resetting the number of beacons (LB) that have not been continuously received to “0” and then checking a PNC selection order included in the received beacon; A fourth step of determining whether to change the PNC selection order; And If the selection order of the PNC is not changed in the fourth step, the process proceeds to the second step again and waits for the beacon. If the selection order of the PNC is changed, the PNC selection order (S) is changed to the PNC selection order included in the received beacon. And a fifth step of waiting for a beacon after resetting to the second step. The method of claim 1, If the beacon is not received in the second step, a sixth step of increasing the number of beacons (LB) that have not been continuously received; A judgment for determining whether the number of beacons (LB) that have not been successively received is smaller than "9", which is smaller than the number added by "4" to the PNC selection order S, and "1" which is "1" larger than twice the number of PNC candidates. 7 steps; If the number of beacons (LB) that have not been continuously received in the seventh step is smaller than the number added by "4" to the PNC selection order S and smaller than "9" which is "1" larger than twice the number of PNC candidates, An eighth step of setting a six-byte information request field to "0" during the CAP period and transmitting a probe request command to the PNC requesting an immediate reception state (Imm_ACK); A ninth step of determining whether to receive “Imm_ACK”; A tenth step of determining whether there is a fixedly available channel allocation (PS CTA) if the “Imm_ACK” is not received in the ninth step; If there is a fixedly available channel assignment (PS CTA) in the tenth step, a probe request requesting whether a beacon is received during the "PS CTA" and an immediate response (Imm_ACK) when a beacon is received. An eleventh step of transmitting a command to a corresponding destination DEV; A twelfth step of determining whether to receive “Imm_ACK”; A thirteenth step of determining whether the beacon number LB that has not been continuously received is smaller than the number greater than "3" than the PNC selection order S when the "Imm_ACK" is not received in the twelfth step; And If the number of beacons (LB) that have not been continuously received in the thirteenth step is smaller than the number greater than "3" than the PNC selection order (S), the process proceeds to the second step again, and when the beacon number LB is large, a new beacon is generated by a new PNC. The PNC handover method in a wireless fan environment, characterized by further comprising the fourteenth step of transmitting. The method of claim 2, Whether the beacon number LB that has not been continuously received in the seventh step is smaller than the number added by " 4 " to the PNC selection order S and smaller than " 9 " If the result of the determination is false, or receives "Imm_ACK" in the ninth step, or "Imm_ACK" in the twelfth step, after resetting the number of beacons (LB) that have not been continuously received to "0" And further comprising a fifteenth step proceeding back to the second step. The method of claim 2, Probe for requesting the beacon reception during the "PS CTA" and an immediate response (Imm_ACK) when the beacon is received if there is no fixedly available channel assignment (PS CTA) in the tenth step Active PNC hand in a wireless fan environment further comprising a sixteenth step of transmitting a request command to another DEV based on the information previously communicated and the PNC selection order information, and then proceeding to the twelfth step again. Over way.

Images