KR20040090018A - Method for saving power of wireless LAN card - Google Patents

Abstract

The present invention relates to a power saving method of a WLAN card.

The present invention includes an active state that performs data transmission and reception, and a doze state that does not perform data transmission and reception, and consumes less power. In the doze state, the radio is activated every reaction cycle time to receive a beacon signal from an access point. In addition to the power saving method of the LAN card, when the data transmission or reception is completed in the active state, it has a standby state is maintained for a set waiting time and then switched to the doze state, and the data to be transmitted or received in the standby state When it is confirmed, the process returns to the active state, and when the holding time of the standby state exceeds the set waiting time, the state is switched to the doze state.

Description

Power saving method of wireless LAN card {Method for saving power of wireless LAN card}

The present invention relates to a wireless LAN, and more particularly, to a power saving method for improving a power saving scheme of a wireless LAN card in a wireless LAN described in IEEE 802.11.

A power saving method of a general WLAN card will be described with reference to FIG. 1. 1 is a conceptual diagram illustrating a power saving operation of a conventional WLAN card for each state. As shown in FIG. 1, the state of a conventional WLAN card may be divided into an active state S1 and a doze state S2. Here, the state of the WLAN card is based on the operation of the WLAN card, and it is preferable to understand the mode of the WLAN card when viewed inside the actual WLAN card. That is, it can be said that the power saving method of the WLAN card is achieved as the active mode and the doze mode.

The active state S1 is a waking state in which a WLAN card can transmit or receive a packet. The doze state S2 is a power saving state in which the WLAN card does not transmit or receive a packet and consumes very little power.

Therefore, when an event for transmitting or receiving a packet occurs, the conventional WLAN card switches from the doze state S2 to the active state S1 to perform packet transmission or reception, and then performs packet transmission or reception. After that, when there is no need to perform any further operation, it automatically switches to the doze state S2. Here, the data of the packet received by the WLAN card is provided to the device equipped with the WLAN card, that is, the notebook, the cellular phone, the PDA, etc., and processed.

Meanwhile, the WLAN card wakes up at a predetermined cycle time during the doze state S2 and checks a beacon signal transmitted from an access point to determine whether there is a signal to receive. At this time, a certain period of time that wakes up from the doze state is called a reaction period (listenInterval). The time of the reaction cycle is usually 100 msec. The reaction cycle time is 100 msec because the generation period of the beacon signal transmitted from the access point is 100 msec.

The beacon signal transmitted from the access point includes destination information of data to be transmitted by the access point as well as a media access control (MAC) address of the access point. Accordingly, the WLAN card checks whether there is data to be transmitted from the access point to itself by checking the beacon signal. If it is determined that there is data to be transmitted to the WLAN card, the WLAN card switches from the doze state to the active state. However, if the WLAN card determines that there is no data to transmit to the access point from the access point, the WLAN card continues in the doze state.

Here, when the WLAN card transitions from the doze state to the active state, the WLAN card transmits a PS-Poll packet indicating the state transition to the access point and requests data to be transmitted to the access point.

When the access point receives the PS-Poll packet, the access point determines that the WLAN card is active and starts transmitting data stored in the buffer to the WLAN card. Then, the WLAN card receives data from the access point, and when the data is received, the WLAN card switches to the doze state. At this time, the WLAN card notifies the access point that it has switched to the doze state by setting the power management bit to '1' in the last response packet or any response packet sent to the access point.

When the access point receives a packet having a power management bit of '1', the access point buffers data transmitted to the WLAN card to be received later, and informs the WLAN card of this fact through a beacon signal.

However, the power saving scheme of the conventional WLAN card as described above switches from the active state to the doze state as soon as the data transmission or reception is completed, so that the data transmission and reception between the source node and the target node are repeated several times. There is a problem of not responding properly.

That is, if the WLAN card immediately switches to the doze state when data transmission or reception between the source node and the target node is repeated several times, the data to be transmitted or received within the response cycle time is not processed immediately. There is a problem that the WLAN card waits until the time of waking up with a reaction cycle or is discarded. In addition, the data transmitted or received at a time longer than the reaction cycle time which is not synchronized with the reaction cycle time in the active state immediately switched to the doze state is also not immediately processed.

The present invention is to solve the above-mentioned problems, the data processing is performed immediately in the situation that the data exchange between the source node and the target node is performed immediately to reduce the packet discard rate and improve the quality of the call It is aimed at letting.

1 is a conceptual diagram showing a power saving operation of a conventional WLAN card for each state.

2 is a conceptual diagram illustrating a power saving operation of a WLAN card to which a WLAN card power saving method according to an embodiment of the present invention is applied;

3 is a view showing the internal structure of one cell (cell) in a general WLAN environment to which the present invention is applied.

4 is a flowchart illustrating a method of power saving of a WLAN card for all data packets according to the first embodiment of the present invention.

5 is a flowchart illustrating a method of power saving of a WLAN card for a real-time voice packet according to a second embodiment of the present invention.

The present invention for achieving the above technical problem is based on the fact that the call quality improvement than the power saving to increase the customer satisfaction. That is, conventionally, when switching from the active state to the doze state immediately, the effect of power saving is great, but in contrast to the disadvantage of not being able to immediately process the transmission or reception data to be processed after the completion of the active state, the present invention provides an active state. Thereafter, a standby state is provided so that data transmitted or received can be processed immediately. The standby state starts when a conventional active state completion condition is satisfied, is maintained for a set wait time, and basically switches to a doze state after the set wait time.

The standby state is a state where the WLAN card is always awake and consumes the same power as the active state. As a result, the standby state may be considered as an extension of the active state.

Since the WLAN card of the present invention has a standby state, the power saving effect is lower than the conventional one by the standby time, but it is possible to immediately process data to be transmitted or received during the standby time, thereby improving the call quality.

Here, the standby state of the WLAN card is switched to the active state immediately after confirming that there is data to be transmitted or received from the access point, or is switched to the doze state when the set waiting time elapses.

Preferably, the waiting time for setting the standby state is a time at which it can be determined that there is no more data to be received and a time at which it can be determined that there is no more data to be transmitted to the target node. This is because the existence of the standby state is meaningless when no further data is exchanged between the source node and the target node.

The set waiting time is obtained by an experiment. According to the experiment, a transmission / reception period of a data packet is about 1 second and a transmission / reception period of general data is about 500 msec.

Accordingly, according to an aspect of the present invention for achieving the above technical problem, a first step of transmitting or receiving data in an active state in the WLAN card power saving method in a wireless LAN environment, and transmitting or receiving data A second step of switching to a standby state and counting the standby state holding time when the completion is completed; and a third step of determining whether the wait state holding time that has been countered has elapsed from the set waiting time in the standby state, and the standby state. In step 4, when the counted standby state holding time has not passed a set time and there is an event of transmitting or receiving data, a fourth step of returning to the active state and returning to the first step, and in the standby state, A fifth step of switching to the doze state when the standby state holding time has passed the set time; and , Each reaction cycle time by receiving a beacon signal from the access point and a sixth step of determining whether there is data to be transmitted or received.

In addition, according to another aspect of the present invention for achieving the above technical problem, the first step of transmitting or receiving data in an active state in the wireless LAN card power saving method in a wireless LAN environment, and transmitting or receiving data Is completed, a second step of determining whether the transmitted or received data is real-time voice data; and if the transmitted or received data is real-time voice data, a third step of switching from the active state to the standby state; A fourth step of switching from the active state to the doze state if the received data is not real time voice data; and a fifth step of counting the standby state holding time at the time of switching when the switch is made to the standby state; In the standby state, when the counted standby state holding time elapses from the set waiting time, the state changes to the doze state, and A sixth step of switching to the active state if there is data to be transmitted or received without the waiting time of the waiting time being set, and receiving and transmitting a beacon signal from the access point at each reaction cycle time in the doze state; Or a seventh step of determining whether there is data to be received.

Hereinafter, with reference to the accompanying Figures 2 to 5 will be described a preferred embodiment of the present invention that can be easily implemented by those skilled in the art.

2 is a conceptual diagram illustrating a power saving operation of a WLAN card to which a WLAN card power saving method according to an embodiment of the present invention is applied. As shown in FIG. 1, the WLAN card of the present invention has three operating states: an active state, a standby state, and a dose state.

The active state is a state under the same condition as the conventional active state and can receive or transmit data as described above, and the dose state can receive or transmit data as a state under the same condition as the conventional doze state. None, but very low power consumption. The standby state is a state in which data can be received or transmitted similarly to the active state, and it is a state of checking whether there is an event to receive or transmit data before the reaction cycle time before switching from the active state to the doze state.

The state according to the power saving method of the WLAN card of the present invention described with reference to FIG. 2 will be clearly understood through the embodiments of the present invention with reference to FIGS.

First, a WLAN environment to which the present invention is applied will be described with reference to FIG. 3.

3 is a diagram illustrating an internal structure of one cell in a general WLAN environment to which the present invention is applied. The present invention applies to all WLAN environments. The WLAN environment is composed of an access point and a wireless terminal (MN). One cell c1 is formed by the access point AP as shown in FIG. 3.

The wireless terminal (MN) has a wireless LAN card with a unique identifier. Since the functions of the wireless terminal (MN) described in the present invention are actually performed by the wireless LAN card, the same reference numerals are given to the wireless LAN card as the wireless terminal.

An access point (AP) is a device that allows all the wireless terminal (MN) located in the cell that is in charge of the access to the WLAN, broadcasts a beacon signal to inform the presence of a certain period time. Then, the WLAN terminal existing in the corresponding cell c1, that is, the WLAN card MN, receives the beacon signal of the access point AP and checks SSID (service set ID) information included in the beacon signal. Determine whether the access point is accessible.

Therefore, each wireless LAN card (MN) is connected to the access point (AP) suitable for its SSID address to perform data transmission and reception with the outside, the access point (AP) broadcast a beacon signal at a predetermined period of 100msec, By performing authentication of the connected WLAN card, the WLAN service is supported for the authenticated WLAN card.

Hereinafter, a power saving method of a WLAN card according to a first embodiment of the present invention will be described with reference to FIG. 4. 4 is a flowchart illustrating a power saving method of a WLAN card for all data packets according to the first embodiment of the present invention.

As shown in FIG. 4, the wireless LAN card (MN) accesses the wireless LAN when authentication is successful in the corresponding cell (S401). The WLAN card (MN) confirms that there is data to be provided to the user in the state of accessing the WLAN through a beacon signal of the access point (AP), or if data to be transmitted internally is generated (S402). From the state to the active state (S404), the data is received or transmitted to complete the data transmission (reception) (S404).

When the WLAN card (MN) completes the transmission (or reception) of the data, the state transitions from the active state to the standby state (S405), and then the time from the time when the transition to the standby state (hereinafter referred to as 'wait time') Count.

The WLAN card (MN) is used as a data to determine whether it is time to switch the counter time to the doze state. That is, the WLAN card MN performs a monitoring operation for comparing the counted waiting time with the setting waiting time (S406), and when the waiting time passes the setting waiting time, the WLAN card (MN) switches from the standby state to the doze state ( S410). At this time, the WLAN card (MN) transmits a signal indicating that the switch to the doze state from the standby state, that is, a signal in which the conventional power management bit includes a '1' to the access point.

However, if there is data to be transmitted or received before the waiting time passes the set waiting time (S407), the WLAN card (MN) switches to the active state again (S408) and transmits or receives the corresponding data (S409). . In addition, the WLAN card MN switches back to the standby state after completing the process S409 (S405), and counters the waiting time to perform the above-described process (process according to the corresponding state in S406 to 410). .

On the other hand, the WLAN card (MN) in the doze state wakes up every 100msec reaction cycle time to check the beacon signal received from the access point (AP) to check whether there is data to be received by itself (S411).

Hereinafter, a second embodiment of the present invention in which power saving operation is performed only when data transmitted and received is a voice packet will be described with reference to FIG. 5. 5 is a flowchart illustrating a method of power saving a WLAN card for a real time voice packet according to a second embodiment of the present invention.

As shown in FIG. 5, the second embodiment of the present invention is similar to the first embodiment of the present invention. However, since the overall operation is for a real-time voice packet, the process of determining whether the data packet being transmitted and received is a voice packet is first performed. It is added to one embodiment.

That is, the wireless LAN card (MN) accesses the wireless LAN (S501), checks whether there is a transmit (receive) packet (S502), and if there exists a transmit (receive) packet, switches to an active state (S503). In step S504, the packet is transmitted (received).

Then, the WLAN card (MN) determines whether the packet being transmitted (received) is a real time voice packet (S505). At this time, the WLAN card MN checks whether the packet transmission period and the packet reception period are the same, and determines that the packet is a real time voice packet when the packet transmission period and the packet reception period are the same.

Therefore, the WLAN card MN cannot determine whether a packet being transmitted and received is a real-time voice packet if the packet is transmitted several times and not received several times.

As a result, the WLAN card MN according to the second embodiment of the present invention adopts the conventional power saving scheme with reference to FIG. 1 until it is determined that the transmitted / received packet is a real time voice packet. That is, the WLAN card MN switches to the doze state immediately after transmitting or receiving data in the active state and switches back to the active state when it is determined whether there is data to be transmitted or received. In this case, when the WLAN card MN switches from the active state to the doze state, a signal indicating that the WLAN card is switched to the doze state, that is, a signal in which the conventional power management bit includes '1' is used as an access point. send.

However, when the WLAN card (MN) determines whether the cycles of the transmitted and received packets are the same several times, that is, if it is determined as a real-time voice packet (S505), the WLAN card (DoN) state after transmitting (receiving) the real-time voice packet The switch to the standby state without switching to (S506). Thereafter, the WLAN card MN performs operations in three states, which are classified into a standby state, a dose state, and an active state, in the same manner as described with reference to FIG. 4.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only and not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

The present invention has an effect of reducing the discard rate of the packet by placing the standby state after the active state, so that the packet can be processed or transmitted within the response period time after the packet is transmitted or received.

Claims (12)

An active state for performing data transmission and reception, and a dosing state that does not perform data transmission and reception, and consumes a small amount of power. In the doze state, the WLAN card is activated every reaction cycle time to receive a beacon signal from an access point. In the power saving method, When the data transmission or reception is completed in the active state, the standby state is maintained for a set waiting time and then switched to the doze state, When the data to be transmitted or received in the standby state is confirmed, switch back to the active state, and when the standby time exceeds the set standby time, switch to the doze state. Way. The method according to claim 1, The wireless LAN card in the standby state transmits a signal indicating that the switch to the doze state to the access point at the time when the standby time exceeds the set standby time. How to save LAN card. The method according to claim 1, The WLAN card in the active state switches to the standby state if the data to be transmitted and received is real-time voice data, and if the data to be transmitted and received is not the real-time voice data, the WLAN card power saving method, characterized in that for switching . In the WLAN power saving method in a WLAN environment, A first step of transmitting or receiving data in an active state; A second step of switching to a standby state when the transmission or reception of data is completed and counting the standby state holding time; A third step of checking whether the counted waiting time holding time has elapsed in the waiting condition; A fourth step in the standby state, when the counted standby state holding time has not passed a set time and there is an event of transmitting or receiving data, switching to the active state and returning to the first step; A fifth step of, in the standby state, switching to a doze state when the counted standby state holding time elapses after a set time; And And a sixth step of determining whether there is data to be transmitted or received by receiving a beacon signal from the access point at each reaction cycle time in the doze state. The method according to claim 4, The setting standby time is a time for determining that there is no more data to be received by the WLAN card, and a time for determining that there is no more data to be transmitted to the target node. Way. The method according to claim 4, The fifth step is a power saving method of a WLAN card, characterized in that for transmitting a signal indicating that the state transition to the doze state from the standby state. In the WLAN power saving method in a WLAN environment, A first step of transmitting or receiving data in an active state; Determining whether the transmitted or received data is real-time voice data when transmission or reception of data is completed; A third step of transitioning from the active state to the standby state if the transmitted or received data is real time voice data; A fourth step of switching from the active state to the doze state if the transmitted or received data is not real time voice data; A fifth step of counting the standby state holding time at the point of switching when the state is switched to the standby state; In the standby state, when the counted standby state holding time elapses from the set waiting time, the state is switched to the doze state, and if there is data to be transmitted or received without passing the set waiting time, the active state. Switching to the sixth step; And And a seventh step of determining whether there is data to be transmitted or received by receiving a beacon signal from the access point at each response cycle time in the doze state. The method according to claim 7, The setting standby time is a time for determining that there is no more data to be received by the WLAN card, and a time for determining that there is no more data to be transmitted to the target node. Way. The method according to claim 7, The fourth step is a power saving method of a WLAN card, characterized in that for transmitting to the access point a signal informing the switch to the doze state from the active state. The method according to claim 7, In the sixth step, the WLAN card power saving method, characterized in that for transmitting to the access point a signal informing that the transition to the doze state. On your computer, A first step of transmitting or receiving data in an active state; A second step of switching to a standby state when the transmission or reception of data is completed and counting the standby state holding time; A third step of checking whether the waiting state holding time which has been counted in the waiting state has passed a setting waiting time; A fourth step in the standby state, when the counted standby state holding time has not passed a set time and there is an event of transmitting or receiving data, switching to the active state and returning to the first step; A fifth step of, in the standby state, switching to a doze state when the counted standby state holding time elapses after a set time; And The computer-readable recording medium having recorded thereon a program capable of executing a sixth step of determining whether there is data to be transmitted or received by receiving a beacon signal from the access point in the doze state. On your computer, A first step of transmitting or receiving data in an active state; Determining whether the transmitted or received data is real-time voice data when transmission or reception of data is completed; A third step of transitioning from the active state to the standby state if the transmitted or received data is real time voice data; A fourth step of switching from the active state to the doze state if the transmitted or received data is not real time voice data; A fifth step of counting the standby state holding time at the point of switching when the state is switched to the standby state; In the standby state, when the counted standby state holding time elapses from the set waiting time, the state is switched to the doze state, and if there is data to be transmitted or received without passing the set waiting time, the active state. A sixth step of switching to; And The computer-readable recording medium having recorded thereon a program capable of executing a seventh step of determining whether there is data to be transmitted or received by receiving a beacon signal from the access point in the doze state.