KR100712878B1 - Synchronization method in WPAN - Google Patents

Abstract

The present invention relates to a synchronization method in a wireless personalization network, and an object of the present invention is to synchronize the duty cycle generated by each coordinator when any device has a coordinator and at the same time it serves as a coordinator for a subordinate device. The present invention provides a synchronization method in a wireless personalization network.

To this end, the present invention provides a synchronization method of a wireless personalization network for coordinating data between a coordinator and a subordinate device of the coordinator using a superframe, wherein the coordinator includes a beacon, an activation period, and a deactivation period of the subordinate device. Generating its own superframe including position information indicating the position of the beacon of the superframe of the subordinate apparatus allocated to the inactive section for synchronizing with the frame, and transmitting the superframe to the subordinate apparatus and receiving the superframe; The subordinate device generates its own superframe in synchronization with the superframe of the coordinator by using the position information included in the superframe, and the coordinator and the subordinate device communicate with each other using the superframe synchronized. It features.

Description

Synchronization method in wireless personalization network

1 illustrates a peer to peer multihop tree network topology.

2A and 2B show the structure and duty cycle of a conventional superframe.

3 shows a structure of a superframe according to an embodiment of the present invention.

4 illustrates a synchronization relationship between duty cycles of respective devices in an embodiment of the present invention.

5 is a flowchart illustrating a collision avoidance process performed by an apparatus having a coordinator and acting as a coordinator in an embodiment of the present invention.

6 shows the results of simulation of energy consumption according to an embodiment of the present invention.

The present invention relates to a synchronization method in a wireless personalization network. More specifically, by matching duty cycles generated by each coordinator, the wireless device can maintain the deactivation interval of each wireless device to maximize the energy efficiency of the wireless device. The present invention relates to a synchronization method in a wireless personalization network.

IEEE 802.15.4 was developed as a standard for low-speed wireless personal area networks (WPANs), which is suitable for low-speed data transfers required over short distances of less than 10 meters, such as homes. It is characterized by the flexibility of the network by including applications and by supporting very low energy consumption and various network topologies.

Network topologies used in WPAN include star type or peer-to-peer type, and peer-to-peer multihop tree type when WPAN is expanded Network topology is used.

1 illustrates a peer to peer multihop tree network topology. In FIG. 1, the main coordinator CD of the WPAN has devices D1-D5 below it, and the devices D2, D3, D5 have devices D2-1, D2-2 below it. , D3-1, D3-2, D5-1). In addition, the device D2-1 has the device D2-1-1 below it. The devices D2, D3, D5 and D2-1 each have their own coordinator and at the same time they act as coordinators for the subordinate devices.

In FIG. 1, the main coordinator CD and the devices D2, D3, D5, and D2-1 serving as coordinators generate a superframe used for communication between the devices, and activate the superframe. Create a duty cycle in which the active section and the inactive section are repeated periodically.

2A shows a conventional superframe structure and duty cycle. As shown in FIG. 2A, the superframe includes a beacon 10, an activation section 20, and a deactivation section 30, and the activation section is again a contention access period (CAP) 40 and a non-competition section. The contention free period (CFP) is divided into 50, and the non-competition period includes a plurality of reserved slots (GTS: Guaranteed Time Slots) 51 to 53 having one or more slots.

In FIG. 2A, the beacon 10 indicates the boundary of the superframe, and the coordinator periodically broadcasts the beacon 10 to synchronize devices connected to the subordinates. The activation section 20 is a section used for data transmission of each device, and the deactivation section 30 is a section where each device waits without transmitting data and is a section in which energy consumption is almost zero.

The contention access section 40 is a section in which each device competes with another device to transmit channel request data in order to receive a channel from a coordinator existing in its upper layer. with Collision Avoidance).

The non-competition section 50 is a section allocated by the coordinator so that the devices requesting the channel through the contention access section 40 can transmit data, and the devices that succeed in the channel request allocate the reserved slots 51 to 53 allocated thereto. Transmit data without competing with other devices.

When the superframe is determined as described above, the coordinator generates a duty cycle in which the activation period and the inactivation period of the superframe are periodically repeated as shown in FIG. 2B.

In a WPAN using a peer-to-peer multihop tree network topology, when a device has its own coordinator and at the same time itself becomes the coordinator of the subordinate device, each coordinator sends a beacon to the underlying device for communication. Since the transmission time points may be different from each other, the synchronization of duty cycles between upper and lower devices may be inconsistent.

If the duty cycle is not synchronized as described above, since the deactivation intervals are not matched between the coordinator and the lower device, the lower device has to be activated for communication with the coordinator, thereby increasing energy consumption. There is this.

In addition, if the duty cycle is synchronized between the coordinator and the lower device, not only the inactivation section but also the activation section may coincide with each other, and thus there is a problem that data collision may occur due to duplication of reserved slots allocated to the non-competition section of each coordinator. .

SUMMARY OF THE INVENTION The present invention solves the above problems, and an object of the present invention is to match the synchronization of duty cycles generated by each coordinator when any device has an coordinator and at the same time it acts as coordinator for the subordinate device. The present invention provides a synchronization method in a wireless personalization network that can be enabled.

Another object of the present invention is to synchronize in a wireless personalization network that can prevent duplication of reserved slots that may occur due to duty cycle matching when any device has a coordinator and at the same time it serves as a coordinator for subordinate devices. To provide a method.

 According to an aspect of the present invention, a coordinator and a subordinate device of the coordinator are in a method of synchronizing a wireless personalization network for data communication using a superframe, wherein the coordinator is configured to beacon, activate, and deactivate the subordinate device. Creates and transmits its own superframe including location information indicating the position of the beacon of the superframe of the sub-device allocated to the inactive section to synchronize with the superframe including the section, and transmits to the sub-device. The subordinate device receiving the frame generates its own superframe in synchronization with the superframe of the coordinator by using the position information included in the superframe, and the coordinator and the subordinate device generate their superframes synchronized with each other. It is characterized by communicating by using.

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The present invention for achieving another object of the present invention uses a superframe between a higher coordinator, a lower device, and a next higher coordinator having the higher coordinator adjusting itself to a higher coordinator and the lower coordinator having a lower coordinating device himself. A synchronization method in a wireless personalization network for performing data communication, the synchronization method comprising: a higher coordinator generating its own superframe including position information for synchronizing with the next higher coordinator, and a position included in the superframe of the higher coordinator The next higher coordinator generates its own superframe, including position information for synchronizing with the superframe of the upper coordinator using the information and synchronizing with the lower device, and included in the superframe of the next higher coordinator. The number of the next higher coordinator using the location information Aligning the frame and the sync and that the slave unit generate their own superframe, characterized in that the communication using the parent coordinator, the second-level adjuster, and the super frame of each of the slave units the synchronization.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

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3 shows a structure of a superframe according to an embodiment of the present invention. As shown in FIG. 3, the superframe according to the embodiment of the present invention includes a beacon 10, an activation section 20, and a deactivation section 30, and the activation section is again a contention access section 40 and a non-competition section. The non-competition section includes a plurality of reserved slots 51 to 53 having one or more slots, and the inactive section 30 includes the last time slot of the superframe, that is, the last time slot of the inactive section. It includes one or more beacon reserved slots (GTS For Beacon, GFS) (61 ~ 63) allocated from.

Of the beacon 10, the activation section 20, the competitive access section 40 and the non-competition section 50, the non-competition section 50 shown in Figure 3 of the reserved slots (51 ~ 53) Since the purpose and function are the same as those shown in FIG. 2, description thereof will be omitted.

Beacon Reserved Slots (GFS) 61-63 assigned to the inactive interval 30 are assigned to the coordinator of their parent when any device has its own coordinator and at the same time it is itself the coordinator of the subordinate device. The allocation of the beacon reserved slot is requested. Then, the beacon is transmitted to the subordinate device using the allocated beacon reserved slot, and the subordinate devices generate the beacons of the superframe based on the position of the transmitted beacon reserved slot. You can match the synchronization of the duty cycle of the devices in the.

In order to synchronize the duty cycle, the allocated beacon reserved slots 61 to 63 become closer to the last slots of the superframe, so the duty cycle and delay difference of the lower device become smaller, thereby improving synchronization efficiency.

Therefore, when the coordinator allocates beacon reserved slots to subordinate devices, priority can be given to particular devices or randomly assigned by applying priorities between devices according to circumstances.

4 illustrates a synchronization relationship between duty cycles of respective devices according to an embodiment of the present invention. As shown in FIG. 4, the coordinator 100 resides on top of device 1 110 and has beacon reserved slots 100-1, 100-2 in order to synchronize the duty cycle with the devices below it. Allocate The beacon reserved slot 100-1 was used to match the duty cycle with other sub-units not shown, and the beacon reserved slot 100-2 was assigned to match the duty cycle with the underlying device 1 100.

Device 1 110 is a lower device of the coordinator 100 and at the same time serves as a coordinator as the higher device of the device 1-1 120. Device 1 110 adjusts the duty cycle with the coordinator 100 by assigning a beacon of the superframe to the position of the beacon timeslot 100-2 assigned by the coordinator 100 to device 1 110. A common section P1 between the deactivation section of 100 and the deactivation section of the device 1110 may be secured as a substantially deactivation section.

The device 1-1 120 is a subordinate device of the device 1 110 and at the same time serves as a coordinator of a device (not shown). The device 1-1 120 matches the duty cycle with the device 1 110 by allocating a superframe beacon at the position of the beacon time slot 110-1 allocated by the device 1 110. ) And a common section P2 between the deactivation section of the device 1-1 and the device 1-120 as a substantially deactivation section.

When the duty cycles of the devices are synchronized in the relationship between the coordinator 100, the device 1 101, and the device 1-1 120 shown in FIG. 4, the inactive as well as the non-competition periods (CFPs) are the same time. In this case, the reserved slots GTS allocated in the non-competition interval CFP may overlap each other.

That is, the device 1 110 shown in FIG. 4 has the coordinator 100 at the upper side and serves as the coordinator of the device 1-1 120 at the lower side. If the reserved slot allocated by the device 1 110 from the coordinator 100 and the reserved slot allocated by the device 1 110 to the device 1-1 120 below it are the same, the device 1 110 is the same. A collision occurs because data must be transmitted and received in time.

5 is a flowchart illustrating a collision avoidance process performed by an apparatus having a coordinator and acting as a coordinator in an embodiment of the present invention. That is, as in the device 1 of FIG. 4, a method for avoiding collision by preventing a device in the middle of the coordinator and the lower device from being allocated a reserved slot at the same time is shown.

First, the device 1 requests the reserved coordinator to allocate a reserved slot (step S10). Then, it is checked whether a reserved slot has been allocated from the coordinator (step S20). If the reserved slot is allocated from the coordinator, it is checked whether an allocation request for the reserved slot occurs from the device 1-1 (step S30). If it is confirmed that the device 1-1 does not request the allocation of the reserved slot, the process returns to the step (step S30) of checking whether a request for the reserved slot allocation occurs again.

If the device 1-1 requests the allocation of the reserved slot, the position of the requested reserved slot is compared with the position of the reserved slot allocated by the coordinator (step S40). If the two positions are the same as the result of the comparison, the device 1 allocates the reserved slot for the device 1-1 to a position different from the one to which it has been allocated so as not to overlap with its assigned position (step S50), If not, the device 1 allocates the reserved slot to the location of the reserved slot requested by the device 1-1.

Then, in the step of confirming whether the reserved slot is allocated from the coordinator (step S20), if it is determined that the reserved slot has not been allocated, it is checked whether there is a request for reserved slot allocation from the device 1-1 (step S70). As a result of the check, if there is a request, the reserved slot is allocated to the requested position (step S80), and if there is no request, the process returns to the step of confirming the allocation request of the reserved slot (step S70).

After allocating the reserved slot to the position requested by the device 1-1, the device 1 checks whether the reserved slot has been allocated from the coordinator (step S90), and if not, repeats the current step (step S90) and assigns the reserved slot. If so, the device 1 checks whether the position of the reserved slot allocated to the device 1-1 is the same as the position of the reserved slot assigned to the device 1 (step S100).

As a result of the check, if the two positions are the same, the device 1 requests the coordinator to reassign the allocation of the reserved slot or in some cases abandons the transmission (step S110), and if the two positions are not the same, the collision avoidance process is terminated.

6 shows the results of simulation of energy consumption according to an embodiment of the present invention. The simulations show an embodiment of the present invention in comparison with slotted CSMA-CA with beacon reserved slots and unslotted CSMA-CA without beacon reserved slots. The device to be simulated is limited to a device having coordinator and subordinate devices simultaneously in a peer-to-peer multihop tree topology.

6, the embodiment of the present invention shows that energy consumption is lower than that of the slotted CSMA-CA and the unslotted CSMA-CA which do not use the beacon reserved slot.

According to the present invention, by assigning a beacon reserved slot to the last part of the deactivation interval of the superframe, the duty cycle between the devices can be synchronized using the beacon reservation slot, and the duty cycle is synchronized so that each device can maximize its deactivation interval. It can secure the energy efficiency. When the duty cycles between the devices are synchronized, the devices located in the middle of the reserved slots are allocated to prevent the collision of the reserved slots so that the positions of the reserved slots do not overlap, thereby increasing the data transmission rate and channel utilization efficiency of each device. .

Claims (4)

A method of synchronizing a wireless personalization network for coordinating data between a coordinator and a subordinate device of the coordinator using a superframe, The supervisor includes position information indicating the position of the beacon of the superframe of the lower device allocated to the inactive section for synchronizing with the superframe including the beacon, the activation section, and the deactivation section of the lower device. Generates a frame and sends it to the lower device, The lower device that receives the superframe generates its own superframe in synchronization with the superframe of the coordinator by using the position information included in the superframe, And the coordinator and the subordinate device communicate using their synchronized superframes. delete delete A method of synchronization in a wireless personalization network for data communication using a superframe between a higher coordinator, a lower device, and a next higher coordinator having the higher coordinator coordinating itself at a higher coordinator and the lower coordinator coordinating itself at a lower coordinator. To The upper coordinator generates its own superframe, including position information for synchronizing with the next higher coordinator, The next higher coordinator generates its own superframe, including the position information for synchronizing with the super frame of the upper coordinator using the position information included in the super frame of the upper coordinator and synchronizing with the lower device. , The subordinate device generates its own superframe in synchronization with the superframe of the next higher coordinator by using position information included in the superframe of the next higher coordinator; And And the higher coordinator, the next higher coordinator, and the lower device communicate using their synchronized superframes.

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