KR200418573Y1 - Apparatus for conserving battery power of mesh points in a mesh network - Google Patents

Abstract

Disclosed is a device for saving power of a battery powered mesh point in a mesh network. In one embodiment, a centralized controller is installed in the mesh network. Each MP signs information associated with MP battery power savings and provides an indication of the battery power associated with each MP to a centralized controller. The centralized controller optimizes the configuration of the mesh network based on MP battery power saving signaling information and battery power level indication. In an alternative embodiment, each MP independently monitors the traffic passing through each MP and the battery power level associated with each MP. Each MP determines whether to activate the power saving function associated with each MP and to sign information associated with MP battery power savings for neighboring MPs in the mesh network.

Description

A device for saving battery power at mesh points in a mesh network {APPARATUS FOR CONSERVING BATTERY POWER OF MESH POINTS IN A MESH NETWORK}

1 is a view showing a wireless mesh network according to the present invention.

2 is a flow chart of a process for saving battery power of an MP using a centralized controller in the mesh network of FIG.

3 is a flow diagram of an alternative process for saving battery power of an MP using a centralized controller in the mesh network of FIG. 1 without using a centralized controller.

4 is a block diagram of an exemplary centralized controller used in the wireless mesh network of FIG.

5 is a block diagram of an exemplary MP used in the wireless mesh network of FIG.

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

110 backbone network (for example, the Internet)

106 mesh portal

120 centralized controller

104 mesh AP

The present invention is directed to a wireless mesh network comprising a plurality of battery-powered mesh points. More specifically, the present invention relates to an apparatus for saving battery power in an MP by implementing a power saving function.

Many schemes have been developed to save battery power of cellular wireless communication system components. For example, a common way to save battery power uses an ideal mode to provide a low duty-cycle background for monitoring the paging channel. However, wireless local area network (WLAN) devices based on IEEE 802.11 cannot efficiently save battery power. Particularly with regard to receive mode operation, it is due to the basic design principle of the wireless multiple access scheme selected by WLAN.

Instantaneous power consumption is generally higher in transmit mode than in receive mode. However, the reception mode is an overall determinant of long-term power consumption in the WLAN device. All incoming packets, regardless of the destination of the incoming packet, are received by the WLAN device based on the distributed coordination function (DCF) or enhanced distributed channel access (EDCA). Because you need to hear about. While the receive mode is in operation, the WLAN device monitors for signal presence on the channel, and when a signal is detected, the WLAN device attempts to decode the preamble and header of the received data packet. If the destination address of the packet conflicts with the address of the device, the device decodes the packet. Otherwise, the packet is discarded.

In some situations, the WLAN must deploy a battery powered MP and mesh access point (MAP), for example for military and / or emergency situations. In such a situation, it would be desirable to provide a system and method for ensuring extended battery life and power efficient operation for battery powered devices.

The present invention is an apparatus for saving the power of the battery power MP in the mesh network. In one embodiment, a centralized controller is provided in the mesh network. Each MP signs information associated with MP battery power savings and provides an centralized controller with an indication of the battery power level associated with each MP. The centralized controller optimizes the configuration of the mesh network based on signaling information and battery power level indication to conserve MP battery power. In an alternate embodiment, each MP separately monitors the traffic flowing through each MP and the battery power level associated with each MP. Each MP determines for neighboring MPs in the mesh network whether to save the power saving function and MP battery power associated with each MP and activate the associated signal information.

The term "wireless transmit / receive unit (WTRU)" herein includes, but is not limited to, a user equipment, mobile terminal, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment.

The present invention is suitable for, but is not limited to, any type of wireless mesh network, including IEEE 802.11x, IEEE 802.15, Bluetooth ^™, HIPERLAN / 2, and the like.

Features of the present invention may be constructed in a circuit that is embedded in an integrated circuit (IC) or that includes a plurality of interconnected components.

1 shows a wireless mesh network 100 according to the present invention. The mesh network 100 includes a plurality of MPs 102, a plurality of mesh access points (APs) 104, a mesh portal 106, and a plurality of WTRUs 108. The MP 102 is performed as the basic forwarding and replacement node in the mesh network 100. MP 102 receives the traffic of the incoming link and forwards the traffic of the outgoing link. In addition, the mesh AP 104 is an MP having an interface for providing wireless access to the WTRU 108 to provide WLAN services in some geographic area. The WTRU 108 communicates with other WTRUs in the mesh network or backbone network 110 (such as the Internet) via mesh AP 104 and mesh portal 106.

 The WTRU 108 generally does not realize the presence of the mesh network 100. The mesh AP 104 forwards the traffic generated by the WTRU 108 to another mesh MP 104 or mesh portal 106 by relaying traffic through the intermittent MP 102. Mesh portal 106 provides connectivity to backbone network 110 for mesh network 100. Thus, mesh portal 106 acts as an MP with a particular interface with backbone network 110.

MP 102, mesh AP 104, and mesh portal 106 are battery powered devices. The present invention provides a method and system for saving battery power of such a battery powered device. As used herein, the terms “mesh point” (MP) and reference numeral 102 may be used to collectively refer to MP 102, MAP 104, and mesh portal 106.

2 is a flowchart of a process 200 for saving battery power of an MP in a mesh network according to an embodiment of the present invention. According to the present invention, a centralized controller 120 is provided in the mesh network 100. The centralized controller 120 may reside anywhere in the mesh network. For example, as shown in FIG. 1, the centralized controller 120 may reside in the mesh portal 106. The centralized controller 120 controls and assigns all settings (eg, routing paths, frequencies, etc.) related to power savings for all MPs 102. The MP 102 is under complete and independent control of the centralized controller 120.

In step 202, at least one of the plurality of MPs 102 of the mesh network 100 signs information about the power saving function to the centralized controller 120. The information about the power saving function includes at least one of a power source, a power saving capability, a power saving request, a power saving feature implemented by the MP 102, and an intended power saving action. In step 204, MP 102 provides battery power level indication to centralized controller 120 periodically or when polled by centralized controller 120. The information regarding the power saving function and the battery power level indication is preferably transmitted by means of a layer 2 (L2) or layer 3 (L3) signaling message, and such a centralized controller 120 is an MP (for battery power saving). Know the requirements of 102).

The information is preferably included in a capability field in a medium access control (MAC) layer message, for example a binding, authentication or probe request message. Alternatively, the information may be included in an information element (IE) of a L2 or L3 signaling message, which may be included in any data, a control message or a management message that is replaced on demand or periodically.

With reference to FIGS. 2 and 4, the centralized controller 120 includes a monitoring unit 122 and a power saving controller 124. The monitoring unit 122 of the centralized controller 120 monitors at least one of the wireless environment, the traffic flow of the mesh network 100, and the level of remaining battery power of the MP 102 (step 206). The centralized controller's power saving controller 124 has a predetermined threshold associated with a particular MP 102 associated with at least one of the wireless environment, the traffic flow of the mesh network 100, and the level of remaining battery power of the MP 102. It is determined whether or not it has reached (step 208). When the predetermined threshold is reached, the power saving controller 124 of the centralized controller 120 commands the specific MP 102 to enter the power saving mode while setting the power saving parameters for the remaining MP 102. (Step 210). In order to see if the centralized controller 120 has issued a page to release the power saving mode of the MP 102, in the power saving mode the MP 102 enters a sleep state and any configured wake-up periodically wakes up and listens for beacons

The power saving controller 124 of the centralized controller 120 assigns a parameter that affects the power saving state of the MP 102, and the action of the MP 102 is adjusted by the parameter while in the power saving mode. .

The power saving parameter may be configured to control the frequency channel during MP operation. MP 102 may operate with multiple radios. In such a case, the MP 102 may transmit and receive on one or more frequency channels at the same time. For example, MP 102 may use two way radio with IEEE 802.11g radio for backhaul and additional IEEE 802.11a radio, or MP 102 may use one IEEE 802.11 for Basic Service Setup (BSS). Two additional IEEE 802.11a radios may be used for the radio and backhaul.

The power saving function is implemented to be turned on and off at least one frequency while in the power saving mode. MP 102 may have a separate modem for each frequency channel, or some of the modems may share multiple frequency channels. In either case, all or part of the modem is turned off, thereby saving battery power. In non-power saving mode, MP 102 transmits and receives on all channels, while in power mode, MP 102 may transmit and receive only on a subset of frequency channels (ie, actually less than its radio frequency (RF) hardware). Allow). The centralized controller 120 may designate a particular frequency channel to be turned off.

Alternatively, the power saving function may be implemented by time adjustment between the MPs 102. When receiving and transmitting data over the mesh network on a particular link, the power saving controller 124 of the centralized controller 102 sets a certain service period interval. (The centralized controller 120 sets an active period and a sleep period for the MP 102.) During a certain sleep period, all the MPs 102 are powered down and no data traffic is transmitted. The centralized controller 120 may adjust the ratio of active period to sleep period in a flexible manner by considering a tradeoff between the capacity of the mesh network 100 and the traffic delay.

In the preferred embodiment, each MP 120 is assigned a separate service time period. Thus, while adjusting the service period between all power saving MPs 102 in the mesh network 100, the centralized controller 120 allocates the service periods for the individual MPs 102. For example, "coordination" of their individual service periods may be implemented by three MPs 102 in a daisy chain, with the first one MP 102 being transmitted only for 0-100 ms. Can sleep at 100 ms-1000 ms, and the second single MP 102 can only receive from 0-100 ms, transmit from 100 ms-200 ms, and sleep at 200-1000 ms. Finally, the third one MP 102 receives at 100 ms-200 ms and sleeps at 0-100 ms and 200 ms-1000 ms. This process is repeated twice each (ie 1000 ms).

The centralized controller 120 may set an algorithm for determining a routing path and connectivity through the mesh network according to the power saving request of the MP. The centralized controller 120 assigns routing paths and data packets. In a method of minimizing the number of MPs in the power saving mode included in the routing path, data packets and routing paths for forwarding patterns through the mesh network 100 are allocated. While the MP is awake to just acknowledge changes in the configured routing path, MPs not included in the routing path may go to sleep. The centralized controller 120 may determine a routing path from the MP 102 taking into account the battery power level indication.

The centralized controller 120 may instruct the MP 102 to collect data packets and transmit them with the same transmission opportunity while in the power transfer mode. This approach reduces the effective transmit and receive periods of the incoming and outgoing data streams, which saves battery power. MP 102 temporarily stores the data packet in a buffer instead of forwarding the data packet each time it receives and bursts in order to maximize the use of any assigned transmission opportunity. This approach minimizes the number of contentions for media access and keeps the RF reception and transmission time low. The centralized controller 120 sets a parameter that takes into account the delay and the required memory. This approach may be applied at both real-time and non-real-time traffic.

In alternative embodiments, the present invention may be implemented in distributed mode. 3 is a flow diagram of a process 300 for conserving battery power of an MP 102 that does not use a centralized controller 120 in accordance with the present invention. The MPs 102 themselves are based on observations of the wireless environment, perceived traffic flows, expected demands, battery power levels, etc., and they themselves are responsible for all power saving parameters (e.g., frequency channels for the user, service intervals for the user, routing paths). , And a set of data packets). The MP 102 is completely autonomous, and entering the power saving mode is under the determination of each independent MP 102.

3 and 5, the MP 102 includes a monitoring unit 502 and a power saving controller 504. The monitoring unit 502 of each MP 102 is a wireless environment, traffic passing through the MP 102 (ie, amount and / or characteristic of traffic (eg, real-time versus non-real time)), MP 102 Monitor at least one of the remaining battery power levels of N, track traffic history and anticipate nearby traffic flow (step 302).

The power saving controller 504 of the MP 102 controls the action of the M 102 while in the power saving mode. The power saving controller 504 of the MP 102 determines whether a predetermined threshold associated with the particular MP 102 has been reached in relation to at least one of a wireless environment, traffic, and level of remaining battery power (step 304). .

When a certain threshold is reached (eg, traffic below some level or battery power level reaching some level), the power saving controller 504 of the particular MP 102 triggers a power saving mode. After informing the neighboring MP of the triggering of the power saving mode (step 306), the neighboring MP of the triggering of the power saving mode is informed, such as broadcasting a null data frame, and then triggering the power saving mode.

While in the power saving mode, the MP 102 implements one or more schemes to save power, as later stated with respect to the first implementation. The MP 102 may optionally turn on and turn off in at least one frequency channel to save battery power. The MP 102 may enter a sleep state at service intervals agreed upon by the MP 102 specifying the timing to enter a sleep state and to wake up. The MP 102 may determine the routing path in a manner that minimizes the number of MPs in the power saving mode included in the routing path. The MP 102 temporarily stores incoming data packets in a bumper and simultaneously transmits aggregate data packets in order to maximize the use of a given transmission opportunity.

The MP 102 may adjust neighbor MPs for operational changes (eg, frequency channel operation, planned service time intervals, collection of routing paths and traffic data), or simply inform of opportunity changes.

Although the present invention has been described for L2 and / or L3 signaling, it should be noted that it can be implemented with any ISO layer of signaling. For example, a protocol such as CAPWAP RFC will be signed on UDP / IP (ie, at L5). In addition, signaling may be implemented on SNMP or at the application layer using appropriate management of software or firmware.

While features and elements of the present invention have been described in the preferred embodiments in particular combinations, each feature or element may be used alone or in various combinations with or without the features and elements of the present invention without other features and elements of the preferred embodiments. have.

According to the present invention, there is provided a device for extending battery life and power efficient operation for a battery powered device.

Claims (8)

In the mesh point (MP) in the mesh network for routing traffic, (a) a monitoring unit configured to monitor traffic passing through the MP and a battery power level associated with the MP; (b) a power saving controller electrically connected to the monitoring unit, wherein the MP activates a power saving function controlled by the power saving controller and signal information associated with MP battery power conservation for other MPs in the mesh network. Determined whether The mesh point that includes. 2. The mesh point of claim 1 wherein said information associated with said MP battery power savings is transmitted by layer 2 (L2) or layer 3 (L3) signaling. 3. The mesh point of claim 2 wherein said information associated with MP battery power savings is included within a capability field in a medium access control (MAC) header. In an integrated circuit (IC) embedded in a mesh point (MP) in a mesh network for routing traffic, (a) a monitoring unit configured to monitor the traffic passing through the MP and the battery power level associated with the MP (b) a power saving controller electrically connected to the monitoring unit, the IC activating a power saving function controlled by the power saving controller and signaling information associated with MP battery power savings for other MPs in the mesh network. Judge whether or not Integrated circuit (IC) embedded in the mesh point (MP) comprising a. The integrated circuit (IC) of claim 4, wherein said information associated with MP battery power saving is transmitted via layer 2 (L2) or layer 3 (L3) signaling. 6. The integrated circuit (IC) of claim 5 wherein said information associated with MP battery power savings is contained within a capability field in a medium access control (MAC) header. For the mesh point (MP) associated with battery power savings, A monitoring unit configured to monitor a power demand of the MP and remaining battery power; And A power saving controller electrically connected to the monitoring unit, the power saving controller configured to trigger a power saving mode when the power demand exceeds a predetermined threshold value A mesh point associated with battery power savings that includes. In an integrated circuit (IC) embedded in a mesh point (MP) configured to conserve battery power, A monitoring unit configured to monitor power demand of the MP and remaining battery power; And A power saving controller electrically connected to the monitoring unit, the power saving controller configured to trigger a power saving mode when the power demand exceeds a predetermined threshold Integrated circuit (IC) embedded in a mesh point (MP) comprising a.

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