KR101401327B1 - Method for collecting low power sensor data of wireless network using periodic preamble sensing and advanced power management - Google Patents

Abstract

The present invention relates to a method for collecting low power sensor data of wireless network using PPS and APM: which variably sets a value of PPSI (periodic preamble sensing interval) for an elastic preamble sensing during a PPS (periodic preamble sensing) mode setting process in a wireless network, for an electricity management using the PSS increasing the value of PPSI when the transmission and receiving of data between one coordinator (repeater) and multiple devices (collector) is intermittent, and reducing the value of PPSI when the transmission and receiving of data is frequent; and activates the devices in the necessary time using the APM (advanced power management) and changes a mode of the devices into a deep sleep mode, thereby reducing the power consumption of the wireless network.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for collecting low-power sensor data in a wireless network using PPS and APM,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of collecting low-power sensor data in a wireless network, and more particularly, to a method of collecting low-power sensor data in a wireless network by periodically preamble (PPSI) Sensing Interval) is variable, and when the transmission and reception of data between one coordinator (a repeater) and a plurality of devices (collectors) is intermittent, the PPSI value is increased, and when data transmission / reception is frequent, In a wireless network using PPS and APM that can reduce power consumption of a wireless network by activating the device only at the time required by APM (Advanced Power Management) as well as power management and switching to Deep Sleep Mode To a method of collecting low-power sensor data.

Generally, a wireless sensor network (WSN) refers to a network that transmits specific information collected by a self-contained sensor between nodes and wirelessly transmits the information to an external device. Typical of these wireless sensor networks

The protocol is the B-MAC (Media Access Control) protocol for ensuring data transmission quality (QoS).

The B-MAC protocol refers to an asynchronous based MAC protocol that does not use a beacon message in consideration of considerable consumption of node energy due to control overhead in synchronizing nodes.

In a wireless sensor network environment where a small amount of data (aka low data) is generated (transmitted / received) frequently, the asynchronous based B-MAC protocol consumes less node energy and transmits data more There is an advantage that it is done quickly. For example, in the B-MAC protocol, there is no energy consumed by the nodes to synchronize and thus the active period is shortened.

FIG. 1 is an explanatory diagram for illustrating a data transmission / reception process of a known B-MAC protocol.

As shown in FIG. 1, all nodes (each of a transmitting node and a receiving node) repeatedly perform an active mode and a sleep mode in a known B-MAC protocol. Here, the sum of the sleep mode execution time (hereinafter referred to as "sleep time ") and the active mode execution time (hereinafter referred to as" active time " In addition, a value obtained by multiplying the active time by a period of "100 " is defined as a duty cycle, which is expressed by the following equation (1).

As mentioned above, in the B-MAC protocol, the node operates asynchronously. In the case of a fixed duty cycle, one cycle is shortened due to the short active time, thereby enabling faster data transmission do.

In the B-MAC protocol, instead of synchronizing with the beacon message, each node has a different active schedule for the active mode. In order to guarantee data communication of each node, a long preamble (Long Preamble) to the network. Here, the time when the transmitting node sends the long preamble is set to be slightly longer than the sleep time of the receiving node.

That is, when the receiver node awakes from the sleep mode and transitions to the active mode, the receiving node receives the long preamble. When receiving the long preamble on the channel, the receiving node transmits a sleep mode So that the active mode is continuously maintained. Such a technique is called low power listening (LPL) technique.

However, in the B-MAC protocol according to the conventional method, all the nodes existing in the one-hop of the transmitting node on the network wake up from the sleep mode and transit to the active mode, All the nodes in the one-hop of the transmitting node can not return to the sleep mode even after the point of time when the channel sampling is performed, and the active mode must be maintained for a long time. There is a problem in that the energy consumption of the node is unnecessarily increased

To solve these problems, Korean Patent No. 10-0893041 has been developed.

In the prior art, a data frame is transmitted from a transmitting node to a receiving node, the data frame including a preload frame consisting of a predetermined number of consecutive preload messages; Data transmitted from the transmitting node to the receiving node; And a request sampling time for changing a channel sampling time of the receiving node, wherein each of the preload messages includes a preamble including synchronization information between the transmitting node and the receiving node; A destination address indicating the receiving node; And a duration representing a remaining time until the transmitting node transmits data, thereby reducing unnecessary node energy consumption due to long preamble overhearing in a wireless sensor network.

However, in the prior art, some nodes in the one-hop of the transmitting node can not return to the sleep mode even after the point of time when the channel sampling is performed, and the active mode must be maintained for a long time.

1. Korean Patent No. 10-0893041 "Adaptive wireless link access control method of sensor network node" (Registered on March 4, 2009)

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus and a method for receiving a data request from a coordinator using a device periodic preamble identification scheme and a data request scheme including a preamble of a coordinator, In a wireless network using a PPS and an APM capable of maintaining a wireless network at a low power level by activating the device only at a necessary time and switching to a deep sleep mode at other times, the data transmission is more flexibly scheduled to minimize unnecessary waiting time And to provide a method for collecting low-power sensor data.

A method for collecting low-power sensor data in a wireless network using a PPS and an APM according to the present invention includes setting a PPSI value of the plurality of devices using a timer installed in a plurality of devices; Determining whether data transmission / reception between the coordinator and the plurality of devices is frequent; If the coordinator transmits and receives data between the coordinator and the plurality of devices frequently, the coordinator transmits a preamble shorter than the PPSI value to the plurality of devices; After the coordinator transmits a preamble shorter than the PPSI value to the plurality of devices, causing the coordinator to reduce a PPSI value set in the plurality of devices; Determining whether data transmission / reception between the coordinator and the plurality of devices is intermittent if transmission / reception of data between the coordinator and the plurality of devices is not frequent; If the transmission and reception of data between the coordinator and the plurality of devices is not intermittent, the process returns to the step of determining whether frequent transmission and reception of data between the coordinator and the plurality of devices is determined, and if transmission / reception of data between the coordinator and the plurality of devices is intermittent, The coordinator transmitting to the plurality of devices a preamble longer than the PPSI value; After the coordinator transmits a preamble longer than the PPSI value to the plurality of devices, the coordinator increases the PPSI value set in the plurality of devices; Determining whether transmission and reception of data between the coordinator and the plurality of devices has been completed; If data transmission / reception between the coordinator and the plurality of devices is not completed, the process returns to the step of determining whether data transmission / reception between the coordinator and the plurality of devices is frequent. If transmission / reception of data between the coordinator and the plurality of devices is completed And switching the plurality of devices to a deep sleep mode.

As described above, the low-power sensor data collection method in the wireless network using the PPS and the APM according to the present invention variably sets the PPSI value so that the PPS mode can be flexibly sensed at the PPS mode setting in the wireless network, When the transmission and reception of data between the plurality of devices is intermittent, the PPSI value is increased, the PPSI value is decreased when the data transmission / reception is frequent, the device is activated only during the required time, The advantage is that data can be collected with low power.

In addition, there is an advantage that system efficiency can be improved by flexible scheduling of data requests.

Brief Description of the Drawings Fig. 1 is an explanatory diagram for illustrating a data transmission / reception process of a known B-MAC protocol. Fig.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for collecting low-power sensor data in a wireless network using a PPS.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for collecting low-power sensor data in a wireless network using PPS.
4 is a flow chart of Fig.
Figure 5 is a flow chart of Figure 3;
FIG. 6 is a diagram illustrating an asynchronous scheduling scheme according to a data request including a preamble of the coordinator of FIG. 3;
FIG. 7 is an explanatory diagram for illustrating a deep sleep switching of a device using an APM in a low power sensor data collection method in a wireless network using an APM according to the present invention; FIG.
FIG. 8 is a flowchart of a periodic preamble identification method and an APM method of a device in a low power sensor data collection method in a wireless network using PPS and APM according to the present invention.
9 is a flowchart of a data requesting method and an APM method including a preamble of a coordinator in a method of collecting low-power sensor data in a wireless network using PPS and APM according to the present invention.

Hereinafter, a method of collecting low-power sensor data in a wireless network using the PPS and APM according to the present invention will be described in detail with reference to the detailed description of embodiments with reference to the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and they may vary depending on the intentions or customs of the client, the operator, the user, and the like. Therefore, the definition should be based on the contents throughout this specification.

Like numbers refer to like elements throughout the drawings.

FIG. 2 is a diagram illustrating a method of periodically checking a preamble of a device in a method of collecting low-power sensor data in a wireless network using a PPS according to the present invention. FIG. FIG. 4 is a flow chart of FIG. 2, FIG. 5 is a flow chart of FIG. 3, and FIG. 6 is a flow chart of a data collecting method of a low power sensor data collecting method in a network according to an embodiment of the present invention. FIG. 7 is a diagram illustrating an asynchronous scheduling scheme according to a data request including a preamble of the coordinator of FIG. 3. FIG. 7 is a flowchart illustrating an asynchronous scheduling method according to an embodiment of the present invention. FIG. 8 is a diagram illustrating an embodiment for showing a deep sleep transition of a device, 9 is a flowchart of a method of collecting low-power sensor data in a wireless network using a PPS and an APM according to the present invention. And the APM method.

The method for collecting low-power sensor data in a wireless network using PPS and APM according to the present invention is a method for collecting sensor data at low power between one coordinator (relay) and a plurality of devices (collectors) As shown in the figure, the coordinator identifies periodic preambles of the plurality of devices, and requests data including the preamble periodically or at any time to the plurality of devices.

In the method for collecting low-power sensor data in a wireless network using the PPS and the APM according to the present invention, it is confirmed that the active mode and the sleep mode of the device are alternately and periodically changed in the PPS (Periodic Preamble Sensing) mode setting in the wireless network .

Here, PPS is derived from the concept of LPL, and it is possible to periodically convert between active mode and sleep mode according to the PPSI value set by the timer installed in the device.

In addition, the PPSI value can be variably set in the mutual communication between the coordinator and the plurality of devices, so that the PPSI value can be flexibly sensed by the preamble. That is, if the coordinator and the plurality of devices frequently transmit and receive data, the PPSI value is reduced, and if the coordinator and the plurality of devices mutually transmit and receive data intermittently, the PPSI value is increased. The larger the power consumption, the more flexible power management is possible. Therefore, the coordinator must send a preamble longer than the PPSI value to the plurality of devices.

Meanwhile, the coordinator can request data to the plurality of devices at any time periodically or at a desired time. Such a data request first transmits a preamble before a packet to activate all the devices in the PPS. At this time, the length of the preamble should be longer than the PPSI value.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

The periodic preamble confirmation of the device and the APM process (see Fig. 8)

First, the PPSI values of the plurality of devices are set using a timer installed in a plurality of devices (S810).

Then, it is determined whether data transmission / reception between the coordinator and the plurality of devices is frequent (S820).

If it is determined in step S820 that data is frequently exchanged between the coordinator and the plurality of devices, a preamble having a shorter PPSI value is transmitted to the coordinator and the plurality of devices in operation S830. In step S830, the coordinator reduces the PPSI value set in the plurality of devices after transmitting a preamble shorter than the PPSI value to the coordinator and the plurality of devices, thereby decreasing the PPSI value set in the plurality of devices (S840).

If it is determined in step S820 that data transmission / reception between the coordinator and the plurality of devices is not frequent, it is determined in step S850 whether transmission / reception of data between the coordinator and the plurality of devices is intermittent.

If it is determined in step S850 that data transmission / reception between the coordinator and the plurality of devices is not intermittent, the process returns to step S820. In step S850, if transmission / reception of data between the coordinator and the plurality of devices is intermittent, And transmits a preamble longer than the PPSI value to the coordinator and the plurality of devices (S860). In step S860, after the coordinator transmits a preamble longer than the PPSI value to the coordinator and the plurality of devices, the coordinator increases the PPSI value set in the plurality of devices, and the PPSI value set in the plurality of devices increases (S870).

Thereafter, it is determined whether data transmission / reception between the coordinator and the plurality of devices has been completed (S880).

If it is determined in step S880 that data transmission / reception between the coordinator and the plurality of devices has not been completed, the process returns to step S820. In step S880, if transmission / reception of data between the coordinator and the plurality of devices is completed, The plurality of devices are switched to the deep sleep mode (S890).

Here, in step S870, as the PPSI value increases, the power consumption decreases.

The data request including the preamble of the coordinator and the APM process (see FIG. 9)

In step S920, the coordinator requests data from a plurality of devices in step S910. At this time, the coordinator requests data to the plurality of devices at any time periodically or at a desired time.

Thereafter, the coordinator transmits the preamble to the plurality of devices (S920). At this time, the length of the preamble should be longer than the PPSI value.

After that, all the devices under PPS are activated (S930).

Thereafter, the active devices transmit data to the coordinator (S940). At this time, the active devices transmit data in their corresponding slot to the coordinator through asynchronous scheduling.

Then, it is determined whether the data transmission of the active devices is completed (S950).

If it is determined in step S950 that the data transfer of the active devices is not completed, the process returns to step S940. If the data transfer of the active devices is completed in step S950, Mode (S960).

On the other hand, in the method of collecting low-power sensor data in a wireless network using PPS and APM according to the present invention, continuous global time synchronization is not achieved. Therefore, the synchronization of performing the PPS between the coordinator and the plurality of devices may not be synchronized with time, and even synchronization among the plurality of devices may not be performed. That is, the PPS can be performed at different time zones without performing the PPS in the same time zone. Therefore, there is a need to synchronize the multiple devices that perform PPS at different times.

Referring to FIG. 6, since the plurality of devices that perform PPS at different time intervals synchronize the communication for on-demand communication at every time the coordinator requests data, , And synchronize with the new criteria at the next new data request.

Meanwhile, referring to FIG. 7, as described above, each device can minimize power consumption by using APM (Advanced Power Management) technique as well as power management through PPS. Therefore, more aggressive power management is performed by activating the device only at a necessary time to transmit data and switching to a deep sleep mode rather than at the other times.

Here, the data request of the coordinator is transmitted to all the devices that are performing the PPS, and the devices selected in the data request transmit data in its corresponding slot to the coordinator through the above-described asynchronous scheduling. At this time, the PPS is not performed until the time until the transmission slot of its own based on the data request and the time of the end of the entire data transmission after the own transmission slot, and is in a deep sleep state.

Also, devices that are not selected for a data request are in a deep sleep state without performing a PPS from the time the request is finished until the time the entire data transmission ends. This allows each device to save even more energy by eliminating unnecessary PPS.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Various changes, modifications or adjustments to the example will be possible. Therefore, the scope of protection of the present invention should be construed as including all changes, modifications, and adjustments that fall within the spirit of the technical idea of the present invention.

Claims (6)

A step (S810) of setting the PPSI values of the plurality of devices using a timer mounted in the plurality of devices;
A step (S820) of determining whether data transmission / reception between the coordinator and the plurality of devices is frequent;
If the coordinator transmits and receives data frequently between the coordinator and the plurality of devices in step S820, the coordinator transmits a preamble shorter than the PPSI value to the plurality of devices in operation S830;
In step S830, the coordinator transmits a preamble shorter than the PPSI value to the plurality of devices, and then the coordinator reduces the PPSI value set in the plurality of devices (S840);
If it is determined in step S820 that data transmission / reception between the coordinator and the plurality of devices is intermittent (S850), if data transmission / reception between the coordinator and the plurality of devices is not frequent.
If the transmission and reception of data between the coordinator and the plurality of devices are not intermittent at step S850, the process returns to step S820. If the coordinator and the plurality of devices transmit and receive data intermittently at step S850, (S860) transmitting a preamble longer than the PPSI value to the device of the mobile station;
(S870), after the coordinator transmits a preamble longer than the PPSI value to the plurality of devices in step S860, the coordinator increases the PPSI value set in the plurality of devices;
Determining whether transmission / reception of data between the coordinator and the plurality of devices is completed (S880); And
If it is determined in step S880 that the transmission / reception of data between the coordinator and the plurality of devices is not completed, the process returns to step S820. In step S880, if the data transmission / reception between the coordinator and the plurality of devices is completed, The method comprising the steps of: (a) changing a sleep mode of the wireless network to a sleep mode; and (S890) switching to a sleep mode.
The method according to claim 1,
Wherein the power consumption is reduced as the PPSI value increases in step S870.
The method according to claim 1,
In operation S820, the coordinator requests data from a plurality of devices in operation S910.
The coordinator transmitting the preamble to the plurality of devices (S920);
Step S930 in which all the devices in the PPS are activated;
Transmitting the data to the coordinator (S940);
Determining whether data transmission of the active devices is completed (S950); And
If it is determined in step S950 that the data transmission of the active devices has not been completed, the process returns to step S940. If the data transfer of the active devices is completed in step S950, (S960). The method of collecting low-power sensor data in a wireless network using PPS and APM.
The method of claim 3,
Wherein the coordinator requests data from the plurality of devices at any time periodically or at a desired time in step S910.
The method of claim 3,
The controller synchronizes the plurality of devices with on-demand data every time the coordinator requests data from the plurality of devices in step S910. The low-power sensor data collection method in the wireless network using the PPS and APM .
The method of claim 3,
Wherein the devices transmit data in their corresponding slots to the coordinator through asynchronous scheduling in step 940. The low power sensor data collection method in a wireless network using PPS and APM.

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